wired – Page 71 – Tech Today w/ Ken May

Wires smaller in diameter than light waves boost solar cell efficiency

Electron micrograph of indium phosphide (InP) nanowires. Each is 180 nanometers in diameter; this diameter allows them to capture more light, making them effective in a photovoltaic solar cell. Wallentin et al. In the continuing quest to create solar cells, researchers seek new materials, use clever techniques, and look for novel physical phenomena to extract the maximum electricity out of sunlight for the lowest cost. One method of extracting more power at a lower cost relies on creating arrays of nanowires that stand vertically on inexpensive substrates. In contrast to the material in ordinary solar cells, nanowires use less material, can potentially be built with less costly materials, and in principle trap more light thanks to the geometry of the arrays. However, most nanowire solar cells are currently outperformed by their conventional counterparts. A new effort used indium phosphide (InP) nanowires with diameters smaller than the wavelength of the light they were trapping. That trick enabled Jesper Wallentin and colleagues to reach comparable efficiencies and slightly higher voltage than a conventional InP solar cell. While the wires only covered 12 percent of the surface area, they exploited a principle known as resonant trapping to extract over half as much current as a full planar cell of InP. This approach could lead to even greater efficiency at lower cost for solar cells. Many candidates for the next generation of photovoltaic (PV) solar cells are being investigated. Research in this area has two goals that don’t always overlap: maximizing the efficiency of converting sunlight into electric current, and reducing cost per unit of electricity. The advantage of nanowire-based cells lies in using a lot less material, since the entire surface need not be covered in PV material. Additionally, the wires themselves can be fabricated from relatively inexpensive semiconductor materials. Read 7 remaining paragraphs | Comments

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Wires smaller in diameter than light waves boost solar cell efficiency

Metamaterials perform image compression before light reaches the sensor

This metamaterial is the aperture of the new microwave imaging device. John Hunt Add image compression to the list of nifty applications for metamaterials. Metamaterials guide light waves to create “ invisibility cloaks ” and bend sound waves to make theoretical noise reduction systems for urban areas. But these materials are tuned to particular wavelengths; some invisibility cloaks don’t work at all visible wavelengths because they leak those wavelengths of light. Now researchers have capitalized on that leakiness to build a new functional device: a microwave imaging system that compresses an image as it’s being collected—not afterward as our digital cameras do. Every pixel in a picture from our digital cameras corresponds to a pixel of information recorded on the detector inside the camera. Once a camera collects all the light intensity information from a scene, it promptly discards some of it and compresses the data into a JPEG file (unless you explicitly tell it to save raw data). You still end up with a decent picture, though, because most of the discarded data was redundant. Compressive sensing aims to ease this process by reducing the amount of data collected in the first place. One way to do this is with a single pixel camera , developed in 2006. These devices capture information from random patterns of pixels around the image, essentially adding the light intensity values of several pixels together. If you know something about the structure of that image—say clusters of bright stars set against a dark sky—you’ll be able to capture that image with fewer measurements than a traditional camera. Read 8 remaining paragraphs | Comments

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Metamaterials perform image compression before light reaches the sensor

FCC adds spectrum to Wi-Fi—but you likely need a new router to use it

Jason Alley The Federal Communications Commission last week said it will add 195MHz of spectrum to Wi-Fi’s 5GHz band. This move is designed to relieve congestion in Wi-Fi networks, particularly in areas of widespread simultaneous usage like airports and sports stadiums . It could help your home network too, but not right away—routers available in stores today may not be able to use the new spectrum at all . Finding out definitively whether today’s routers will support the new spectrum is difficult, partly because the FCC still has to issue specific rules governing its use. We’ve hit up router vendors and other industry people to find out whether software updates might let current routers access the new spectrum. While the results were a bit muddled, it seems safe to say no one is guaranteeing today’s routers will get the benefit of the new 195MHz. Even the latest routers supporting the ultra-modern 802.11ac standard may be left behind. Cisco refused to comment at all, telling us only “Cisco has not made any announcements about this so cannot discuss at this time.” Buffalo told us “the chip vendors will need to work on it” and that “they will at least to have to make changes to the hardware driver. … The magnitude of that change will determine if Buffalo is able to use the same hardware.” Read 21 remaining paragraphs | Comments

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FCC adds spectrum to Wi-Fi—but you likely need a new router to use it

Leader of BitTorrent piracy ring sentenced to five years in prison

The leader of the notorious IMAGiNE BitTorrent piracy ring, Jeramiah Perkins, was sentenced on Thursday to five years in prison, the largest sentence for the group’s five top administrators. In August 2012, Perkins pleaded guilty to one count of conspiracy to commit criminal copyright infringement. After being given the maximum sentence today, Perkins was also ordered to serve three years under “supervised release” and must pay $15,000 in restitution. As we reported in April, the group used infrared and FM receivers and camcorders to capture new releases in movie theaters. In a statement , the Department of Justice cited testimony from the Motion Picture Association of America, calling the group “the most prolific motion picture piracy release group operating on the Internet from September 2009 through September 2011.” Read 2 remaining paragraphs | Comments

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Leader of BitTorrent piracy ring sentenced to five years in prison

Earthworm guts become factory for nanoparticles

Enlarge / Meet the latest quantum dot assembly factory. Colorado State Quantum dots are nanoscale-sized pieces of semiconductor. Their small size ensures that quantum effects, like the Pauli exclusion principle, influence the behavior of electrons within them. This gives the dots properties that a bulk material with the same composition lacks, and it makes them appealing candidates for things like tiny lasers, photovoltaic materials, and LEDs. Another area where they’ve shown promise is medical imaging. In terms of absorbing and emitting light, quantum dots behave much like the fluorescent molecules we can use to label cells of interest. But, since their fluorescent properties depend on the shape of the particles rather than the chemical structure of a molecule, they are much less prone to undergoing reactions that destroy their fluorescence. The problem is that most semiconductors aren’t especially biocompatible, meaning additional chemical reactions need to be performed before the dots can attach to or enter cells. Some researchers have started to look towards making the dots in biological systems, figuring that the output would necessarily be biocompatible. After some successes with bacteria and yeast, they’ve moved on to a larger target: the earthworm. And it appears to work very well. Read 6 remaining paragraphs | Comments

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Earthworm guts become factory for nanoparticles

“Neuristor”: Memristors used to create a neuron-like behavior

A cartoon showing spikes of activity traveling among neurons. UC Berkeley Computing hardware is composed of a series of binary switches; they’re either on or off. The other piece of computational hardware we’re familiar with, the brain, doesn’t work anything like that. Rather than being on or off, individual neurons exhibit brief spikes of activity, and encode information in the pattern and timing of these spikes. The differences between the two have made it difficult to model neurons using computer hardware. In fact, the recent, successful generation of a flexible neural system required that each neuron be modeled separately in software in order to get the sort of spiking behavior real neurons display. But researchers may have figured out a way to create a chip that spikes. The people at HP labs who have been working on memristors have figured out a combination of memristors and capacitors that can create a spiking output pattern. Although these spikes appear to be more regular than the ones produced by actual neurons, it might be possible to create versions that are a bit more variable than this one. And, more significantly, it should be possible to fabricate them in large numbers, possibly right on a silicon chip. The key to making the devices is something called a Mott insulator. These are materials that would normally be able to conduct electricity, but are unable to because of interactions among their electrons. Critically, these interactions weaken with elevated temperatures. So, by heating a Mott insulator, it’s possible to turn it into a conductor. In the case of the material used here, NbO 2 , the heat is supplied by resistance itself. By applying a voltage to the NbO 2 in the device, it becomes a resistor, heats up, and, when it reaches a critical temperature, turns into a conductor, allowing current to flow through. But, given the chance to cool off, the device will return to its resistive state. Formally, this behavior is described as a memristor. Read 4 remaining paragraphs | Comments

Steam for Linux beta now open to the public

Good news for those who didn’t score an invite to the first round of Valve’s closed beta of Steam for Linux . The service is now available to anyone running Linux the latest build of Ubuntu (still no word on when the service is coming to other distros) (seems it runs on multiple different Linux builds now. Apologies). The new, wider release comes with a handy installer package , but those who are already in the closed beta can just upgrade to the latest version within Steam. Valve has also opened up a new Github repository to organize bug tracking for beta testers. That’s what you Linux people like to do, right? Find and catalog bugs? Since the closed beta launch in early November, Steam has expanded its selection of available Linux games from 24 to 39, a list still dominated by indie games. However, THQ president Jason Rubin recently tweeted that the struggling publisher was “evaluating cost/benefit” of Linux development, based on fan feedback in the wake of the company’s successful Humble Bundle experiment . Read on Ars Technica | Comments

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Steam for Linux beta now open to the public

Anonymous sets sights on an old enemy—the Westboro Baptist Church

That link? It leads to a survey entitled, “Interactive Butthurt Report v. 2.0.” Nothing is beneath the Westboro Baptist Church, as evidenced by the group’s announcement to picket outside Sandy Hook Elementary School in wake of the recent tragedy. The group’s most recent, perhaps most deplorable decision has apparently irked one of its oldest enemies : infamous hacker collective Anonymous. In response to the WBC’s plans early today, Anonymous tweeted , “It’s so nice of #WBC to provide the internet with a list of their twitter handles…” Roughly one hour later, they revealed their plans for the WBC : “#WBC GodHatesFags Site Admin gets #DOX’d via: Anonymous.” DOX, of course, refers to the work Anonymous did to find and publish a list of WBC members complete with e-mails, phone numbers, and even home addresses—all for the adoring public to access. In addition to the DOXing, Anonymous has repeatedly promoted a whitehouse.org petition to have the WBC recognized legally as a hate-group . The petition was created on Friday and it has already doubled the required 25,000 signatures. Read 1 remaining paragraphs | Comments

Google phasing out ActiveSync push mail for free customers

Calling it “Winter cleaning,” Google has announced that from January 30, 2013, users of Google Mail, Calendar, and Contacts will no longer receive Exchange ActiveSync (EAS) support on their accounts. EAS provides push mail and synchronization of contacts and calendars to a number of mobile platforms, including iOS, Symbian, and Windows Phone. It’s also one of the protocols that Windows 8’s Metro Mail app uses, as does Outlook 2013. Currently, users of Google’s services can enable EAS support to use their Google accounts with suitable devices. After the cut off, existing users will continue to be able to use EAS with their devices, but those users won’t be able to add new devices. All future devices will have to use IMAP for their mail, CalDAV for calendar sync, and CardDAV for contact sync. Android and iOS users can use these protocols, but many others will be left high and dry. Push mail, in particular, could be left behind, as many platforms (including iOS) don’t support the IMAP IDLE push mail feature. Read 4 remaining paragraphs | Comments

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Google phasing out ActiveSync push mail for free customers

Seattle announces its own gigabit Internet service

This map only shows some parts of the city that Seattle Gigabit aims to serve. Gigabit Seattle One day after Google’s executive chairman, Eric Schmidt, proclaimed Google Fiber was ” not an experiment ,” the Emerald City decided that it too wants in on some of that sweet gigabit speed . On Thursday, Seattle Mayor Mike McGinn announced the city reached an agreement with Gigabit Squared and the University of Washington to bring 1 Gbps connections, taking advantage of the city’s own underused fiber. Seattle abandoned its plan for a municipal network last summer. A connected city wireless network, which would obviously be slower, is also in the works. “The plan will begin with a demonstration fiber project in twelve Seattle neighborhoods and includes wireless methods to deploy services more quickly to other areas,” the city wrote in an online statement . Read 5 remaining paragraphs | Comments

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Seattle announces its own gigabit Internet service