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World's Smallest Battery: Real-Time Observation of Nanowire Anode to Help Improve Lithium Batteries ScienceDaily (Dec. 10, 2010) — A benchtop version of the world's smallest battery -- its anode a single nanowire one seven-thousandth the thickness of a human hair -- has been created by a team led by Sandia National Laboratories researcher Jianyu Huang. To better study the anode's characteristics, the tiny rechargeable, lithium-based battery was formed inside a transmission electron microscope (TEM) at the Center for Integrated Nanotechnologies (CINT), a Department of Energy research facility jointly operated by Sandia and Los Alamos national laboratories. Says Huang of the work, reported in the Dec. 10 issue of the journal Science, "This experiment enables us to study the charging and discharging of a battery in real time and at atomic scale resolution, thus enlarging our understanding of the fundamental mechanisms by which batteries work." Because nanowire-based materials in lithium ion batteries offer the potential for significant improvements in power and energy density over bulk electrodes, more stringent investigations of their operating properties should improve new generations of plug-in hybrid electric vehicles, laptops and cell phones. "What motivated our work," says Huang, "is that lithium ion batteries [LIB] have very important applications, but the low energy and power densities of current LIBs cannot meet the demand. To improve performance, we wanted to understand LIBs from the bottom up, and we thought in-situ TEM could bring new insights to the problem." Battery research groups do use nanomaterials as anodes, but in bulk rather than individually -- a process, Huang says, that resembles "looking at a forest and trying to understand the behavior of an individual tree." The tiny battery created by Huang and co-workers consists of a single tin oxide nanowire anode 100 nanometers in diameter and 10 micrometers long, a bulk lithium cobalt oxide cathode three millimeters long, and an ionic liquid electrolyte. The device offers the ability to directly observe change in atomic structure during charging and discharging of the individual "trees." An unexpected find of the researchers was that the tin oxide nanowire rod nearly doubles in length during charging -- far more than its diameter increases -- a fact that could help avoid short circuits that may shorten battery life. "Manufacturers should take account of this elongation in their battery design," Huang said. (The common belief of workers in the field has been that batteries swell across their diameter, not longitudinally.) Huang's group found this flaw by following the progression of the lithium ions as they travel along the nanowire and create what researchers christened the "Medusa front" -- an area where high density of mobile dislocations cause the nanowire to bend and wiggle as the front progresses. The web of dislocations is caused by lithium penetration of the crystalline lattice. "These observations prove that nanowires can sustain large stress (>10 GPa) induced by lithiation without breaking, indicating that nanowires are very good candidates for battery electrodes," said Huang. "Our observations -- which initially surprised us -- tell battery researchers how these dislocations are generated, how they evolve during charging, and offer guidance in how to mitigate them," Huang said. "This is the closest view to what's happening during charging of a battery that researcher have achieved so far." Lithiation-induced volume expansion, plasticity and pulverization of electrode materials are the major mechanical defects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, Huang said. "So our observations of structural kinetics and amorphization [the change from normal crystalline structure] have important implications for high-energy battery design and in mitigating battery failure." The electronic noise level generated from the researchers' measurement system was too high to read electrical currents, but Sandia co-author John Sullivan estimated a current level of a picoampere flowing in the nanowire during charging and discharging. The nanowire was charged to a potential of about 3.5 volts, Huang said. A picoampere is a millionth of a microampere. A microampere is a millionth of an ampere. The reason that atomic-scale examination of the charging and discharging process of a single nanowire had not been possible was because the high vacuum in a TEM made it difficult to use a liquid electrolyte. Part of the Huang group's achievement was to demonstrate that a low-vapor-pressure ionic liquid -- essentially, molten salt -- could function in the vacuum environment. Although the work was carried out using tin oxide (SnO2) nanowires, the experiments can be extended to other materials systems, either for cathode or anode studies, Huang said. "The methodology that we developed should stimulate extensive real-time studies of the microscopic processes in batteries and lead to a more complete understanding of the mechanisms governing battery performance and reliability," he said. "Our experiments also lay a foundation for in-situ studies of electrochemical reactions, and will have broad impact in energy storage, corrosion, electrodeposition and general chemical synthesis research field." Other researchers contributing to this work include Xiao Hua Liu, Nicholas Hudak, Arunkumar Subramanian and Hong You Fan, all of Sandia; Li Zhong, Scott Mao and Li Qiang Zhang of the University of Pittsburgh; Chong Min Wang and Wu Xu of Pacific Northwest National Laboratory; and Liang Qi, Akihiro Kushima and Ju Li of the University of Pennsylvania. Funding came from Sandia's Laboratory Directed Research and Development Office and the Department of Energy's Office of Science through the Center for Integrated Nanotechnologies and the Energy Frontier Research Centers program. Sursa
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It's official, Wave fans: the Apache Software Foundation has accepted Wave for its incubator program. What's this mean? Well, the group will oversee future development of the Wave Federation protocols and the Wave In A Box product -- and those of you who absolutely cannot live without your Waves won't be left out in the cold. Rounding out support from Apache and Google are representatives from Solute, Novell, SESI, University Duisburg-Essen, and Wikileaks (OK, we made that last one up). Best of luck to ya! Sursa
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Amazon's investment of $100-150 million in Groupon competitor LivingSocial will be announced later today, a source familiar with the situation tells us. All Things D's Kara Swisher reported that the two companies were close to an agreement yesterday. The investment is said to value LivingSocial at "several billion dollars." The news comes as Groupon is reportedly considering a $6 billion acquisition offer ($5.3 billion plus a $700,000 earnout) from Google. An official announcement is expected within the next few hours. Critics of Google's bid have pointed out that the model has very low barriers to entry, with hundreds of competitors. But it's worth pointing out that LivingSocial is the only competitor that has reached a scale remotely close to Groupon's. An industry source estimates that the next nearest competitors -- Tippr and BuyWithMe -- are probably about a tenth the size of LivingSocial. Sursa
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Latest 10 virus alerts - Top 10 virus hoaxes
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What Einstein called his worst mistake, scientists are now depending on to help explain the universe. In 1917, Albert Einstein inserted a term called the cosmological constant into his theory of general relativity to force the equations to predict a stationary universe in keeping with physicists' thinking at the time. When it became clear that the universe wasn't actually static, but was expanding instead, Einstein abandoned the constant, calling it the '"biggest blunder" of his life. But lately scientists have revived Einstein's cosmological constant (denoted by the Greek capital letter lambda) to explain a mysterious force called dark energy that seems to be counteracting gravity — causing the universe to expand at an accelerating pace. A new study confirms that the cosmological constant is the best fit for dark energy, and offers the most precise and accurate estimate yet of its value, researchers said. The finding comes from a measurement of the universe's geometry that suggests our universe is flat, rather than spherical or curved. Geometry of the universe Physicists Christian Marinoni and Adeline Buzzi of the Universite de Provence in France found a new way to test the dark energy model that is completely independent of previous studies. Their method relies on distant observations of pairs of galaxies to measure the curvature of space. "The most exciting aspect of the work is that there is no external data that we plug in," Marinoni told SPACE.com, meaning that their findings aren't dependent on other calculations that could be flawed. The researchers probed dark energy by studying the geometry of the universe. The shape of space depends on what's in it — that was one of the revelations of Einstein's general relativity, which showed that mass and energy (two sides of the same coin) bend space-time with their gravitational force. Marinoni and Buzzi set out to calculate the contents of the universe — i.e. how much mass and energy, including dark energy, it holds — by measuring its shape. There were three main options for the outcome. Physics says the universe can either be flat like a plane, spherical like a globe, or hyperbolically curved like a saddle. Previous studies have favored the flat universe model, and this new calculation agreed. Flat universe The geometry of space-time can distort structures within it. The researchers studied observations of pairs of distant galaxies orbiting each other for evidence of this distortion, and used the magnitude of the distortion as a way to trace the shape of space-time. To discover how much the galaxy pairs' shapes were being distorted, the researchers measured how much each galaxy's light was red-shifted — that is, budged toward the red end of the visual spectrum by a process called the Doppler shift, which affects moving light or sound waves. The redshift measurements offered a way to plot the orientation and position of the orbiting pairs of galaxies. The result of these calculations pointed toward a flat universe. Marinoni and Buzzi detail their findings in the Nov. 25 issue of the journal Nature. Understanding dark energy By providing more evidence that the universe is flat, the findings bolster the cosmological constant model for dark energy over competing theories such as the idea that the general relativity equations for gravity are flawed. "We have at this moment the most precise measurements of lambda that a single technique can give," Marinoni said. "Our data points towards a cosmological constant because the value of lambda we measure is close to minus one, which is the value predicted if dark energy is the cosmological constant." Unfortunately, knowing that the cosmological constant is the best mathematical explanation for how dark energy is stretching out our universe doesn't help much in understanding why it exists at all. "Many cosmologists regard determining the nature of dark energy and dark matter as the most important scientific question of the decade," wrote Alan Heavens of Scotland's University of Edinburgh in an accompanying essay in the same issue of Nature. "Our picture of the universe involves putting together a number of pieces of evidence, so it is appealing to hear of Marinoni and Buzzi's novel technique for testing the cosmological model, not least because it provides a very direct and simple measurement of the geometry of the universe." Sursa
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World, Meet RockMelt Hello Interwebs! The rumors are true… starting today, we’re offering access to an early version of RockMelt, a new browser designed around you and how you use the Web. RockMelt does more than just navigate Web pages. It makes it easy for you to do the things you do every single day on the Web: share and keep up with your friends, stay up-to-date on news and information, and search. And of course, RockMelt is fast, secure, and stable because it’s built on Chromium, the open source project behind Google’s Chrome browser. It’s your browser – re-imagined and built for how you use the Web. If you can stand a few kinks and bugs, sign up for early access, and we’ll get you an invitation as soon as we can. We’d love to know what you think. Your World Built into Your Browser With RockMelt we’ve re-thought the user experience because a browser can and should be about more than simply navigating Web pages. Today, the browser connects you to your world. Why not build your world right into your browser? Your friends are important to you, so we built them in. Now you’re able to chat, share that piano-playing-cat video everyone’s going to love, or just see what your friends are up to, regardless of what site you’re on. Your favorite sites are important to you, so we built them in too. Now you can access them from anywhere, without leaving the page you’re on. And RockMelt will tell you when something new happens. Share or tweet links often? Yeah, us too. No more wading through each site’s goofy share widget or copy-pasting URLs. We built sharing directly into the browser, right next to the URL bar. Like a site or story? Click “Share” and BAM – link shared. You can use it on any site to post to Facebook or tweet about it on Twitter. It’s just one click away. That easy. Personalized and Backed by the Cloud Wherever you go on the Internet, RockMelt makes the Web a personal experience. Because RockMelt is the first browser you log into, it unlocks your Web experience with your Facebook friends, your feeds, your favorite services, even your bookmarks and preferences. RockMelt is also the first browser to be fully backed by the cloud. This means you can access your personal browsing experience from anywhere, and you get quick updates from the people and sites that are important to you. Behind the scenes, RockMelt is always working on your behalf. Do you visit the same site 10 times a day, checking for new posts or updates? Well, RockMelt keeps track of all your favorite sites for you, alerting you when a new story comes out, a friend posts new pictures, or a new video is available. And when you open a RockMelt feed, the content is already waiting for you. You can Like, comment, reply, retweet, share - all the actions you’ve come to expect from each service you follow. Faster Search Last but not least, RockMelt makes search faster. And better. We got tired of clicking back and forth trying to find the right search result. So we made search as simple as leafing through a magazine. With RockMelt, you can use your keyboard to flip through Google search results and pick the one you want. Super fast. Super cool. Rock Solid Foundation Any intro to RockMelt wouldn’t be complete without recognizing all the tremendous work that came before us—and which we’ve built upon. We’re based on Chromium, the open source project behind Google’s Chrome browser, which in turn is based on WebKit, the open source HTML layout engine used by Apple, as well as a host of other projects from Mozilla and others. These projects, which we contribute to, represent the best browser technology out there. RockMelt wouldn’t be possible without these projects, as well as the open APIs, help and support we’ve received from Facebook, Twitter, and others. We’re proud and deeply grateful to be able to build on the shoulders of these giants. Thanks friends! Get Your RockMelt On! After two years of work, RockMelt is still a baby. It’s our baby and we’re proud of it, but we’re most excited about what it will grow into. We’ve just scratched the surface of what we want to do. If you’re on Mac or Windows and you don’t mind some kinks and bugs, we hope you’ll sign up for early access and let us know what you think! We are sending out invitations as fast as we can, while making sure our service scales up. We hope you like RockMelt as much as we do. You can follow our blog or our Twitter account or like us on Facebook for updates. Happy browsing! YouTube - RockMelt - Your Browser. Re-Imagined. Our First Update to RockMelt Beta! Sursa
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Arithmetic Challenge are doar 60 de secunde
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Many people believe that chess is the ultimate game. It requires skill, strategy and the ability to think ahead. There are some moves, however, that can bring crushing defeat to an opponent very early on, sometimes before they even know what hit them. This guide provides step by step instructions on how to execute a classic chess strategy that will defeat inexperienced players in just four short moves. Instructions Things You'll Need: Chess board Opponent 1. 2. 3. 4. Tips & Warnings This strategy may not work every time. A player may see this coming, or inadvertently move a piece that throws a wrench in the monkey works. It is still good to try the first time you play someone so that you will have a feel for how advanced your opponent is. Inexperienced chess players usually fall for this move very easily. Be warned, however, that experienced players will often consider it to be a cheap shot and will try very hard to take you down if they see you attempting this tactic. sursa
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The number system what we use today (1,2,3,4,5…) is called Arabic Numbers System. We also have Roman Numbers System (I, II, III, IV, V, …) which is rarely being used. Have you ever thought WHY One is 1, Two is 2, Three is 3 … and so on? It is all because of Angles. Yes, it is the number of angles in each letter. The following image has ancient Arabic numbers. All the angles that are formed in these letters are mentioned by the letter o. The number of angles gives meaning to each letters. Number 1 has one angle Number 2 has two angles Number 3 has three angles Sursa
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SMS la 330 text: 100 min pentru 100 de minute in reteaua orange; cost mesaj zero Sursa
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"fumatul ucide încet dar sigur, nu ne grabim!"