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Japan invents speech-jamming gun that silences people mid-sentenceUpdated: Friday, 02 Mar 2012, 6:43 PM ESTPublished : Friday, 02 Mar 2012, 8:26 AM ESTTOKYO (Newscore) - Japanese researchers have invented a speech-jamming gadget that painlessly forces people into silence.Kazutaka Kurihara of the National Institute of Advanced Industrial Science and Technology, and Koji Tsukada of Ochanomizu University, developed a portable "SpeechJammer" gun that can silence people more than 30 meters away.The device works by recording its target's speech then firing their words back at them with a 0.2-second delay, which affects the brain's cognitive processes and causes speakers to stutter before silencing them completely.Describing the device in their research paper, Kurihara and Tsukada wrote, "In general, human speech is jammed by giving back to the speakers their own utterances at a delay of a few hundred milliseconds. This effect can disturb people without any physical discomfort, and disappears immediately by stopping speaking."They found that the device works better on people who were reading aloud than engaged in "spontaneous speech" and it cannot stop people making meaningless sounds, such as "ahhh," that are uttered over a long time period.Kurihara and Tsukada suggested the speech-jamming gun could be used to hush noisy speakers in public libraries or to silence people in group discussions who interrupt other people's speeches."There are still many cases in which the negative aspects of speech become a barrier to the peaceful resolution of conflicts," the authors said.
Oh, sure, just like the flying cars we were supposed to have by now.
How Cellulose Could Make Fibers As Strong As Steelby Francie Diep26 March 2012 05:57 PM ET Researchers are working on different applications for an extremely porous, light and strong "aerogel" made of cellulose. This photo shows a non-cellulose, NASA-made aerogel. Credit: NASA People have long used cellulose — the indigestible, woody fibers in plants — to make paper, but one group of scientists is looking to make cellulose items that are a little more sophisticated. On March 25, materials scientist Olli Ikkala presented one cellulose-based material he made that's almost as strong as steel and another that can float while carrying cargo 1,000 times its own weight. He was part of a round of presentations dedicated to cellulose at the American Chemical Society's national meeting in San Diego. People are interested in sustainable and renewable things, Harry Brumer, a chemist at the University of British Columbia, said during a press conference. So he and his colleagues thought this was the right time for a scientific meeting about some of the most abundant, renewable stuff on Earth. Ikkala is especially interested in cellulose as a future replacement for petroleum, which is a key ingredient in everything from plastics to tire rubber. "It's going to happen sooner or later that the oil-based materials become—the price becomes less and less competitive," he said during the conference.In 2010, Ikkala, who researches at Helsinki University of Technology in Finland, and several colleagues published a way of making an extraordinarily light, porous material called an aerogel out of cellulose produced by bacteria. They found that cellulose makes a flexible aerogel, unlike other aerogels, which are stiff and can't bend. They also magnetized the material in a bath of cobalt and iron. The material could be used in electronics and in industrial devices that need to control tiny amounts of fluid, they wrote. Since then, they've worked to make other interesting versions of their aerogel, which is comprised of tiny, nano-size fibers of cellulose.They have created a material that repels water, which could be used for self-cleaning surfaces and to make surfaces that don't accumulate ice. They combined the aerogel with graphene, carbon arranged in a layer one atom thick. The result was a material whose strength is "in the range of steel, or even higher than some grades of steel," Ikkala told InnovationNewsDaily during a phone call before the press conference started. He presented about the material at the American Chemical Society conference and is in the process of publishing his findings from that experiment, he said. In 2011, his team covered the aerogel's cellulose fibers with titanium dioxide, which repels water but absorbs oil. Such a material could work like a "diaper" for absorbing oil spills, he said. They made the diaper-style material extremely buoyant, so workers could float it on spill-polluted waters to clean up the oil. Afterward, cleanup crews could collect the oil for reuse or burn it.Scientists have long been interested in reproducing nature's materials and fabrics, such as spider silk, which researchers are interested in for its strength, flexibility and low weight. "The problem in those materials is that the biosynthesis is extremely slow," Ikkala told InnovationNewsDaily. Besides his cellulose work, he is trying to find faster, easier ways of reproducing silk and nacre, the material that oysters use to make pearls. Though the eco-friendly materials he studies aren't ready for consumer products yet, people are likely to see nature-inspired materials in a few years, Ikkala said. "This is an ongoing and extremely important field to make lightweight construction materials, but it's still in progress."
New Method for Continuous Production of Carbon NanotubesScienceDaily (Apr. 12, 2012) — A group of researchers from Universiti Sains Malaysia (USM) have successfully created a new method for producing carbon nanotubes. The new method is capable of reducing the price of carbon nanotubes from $100 - $700 US to just $15 to $35 US for each gram, much lower than world market prices.The method known as the Continuous Production Method of Carbon Nanotubes using Rotation Reactor is the first ever created in Southeast Asia.Carbon nanotubes are widely used in the production of end products such as memory chips, rechargeable batteries, tennis rackets, badminton rackets, bicycles, composite to manufacture cars, airplanes and so forth.The research team leader, Assoc. Dr. Abdul Rahman Mohamed said, a new rotation of the reactor system is designed to enable the continuous production of carbon nanotubes without compromising the quality and authenticity."The system is capable of producing up to 1000 grams of carbon nanotubes a day,'' he said.He added that the developed system is also environmentally friendly as it operates at atmospheric conditions, cost effective and does not require a large space to operate the reactor.
TV as Thin as a Sheet of Paper? Printable Flexible Electronics Just Became Easier With Stable ElectrodesScienceDaily (Apr. 19, 2012) — Imagine owning a television with the thickness and weight of a sheet of paper. It will be possible, someday, thanks to the growing industry of printed electronics. The process, which allows manufacturers to literally print or roll materials onto surfaces to produce an electronically functional device, is already used in organic solar cells and organic light-emitting diodes (OLEDs) that form the displays of cellphones.Although this emerging technology is expected to grow by tens of billions of dollars over the next 10 years, one challenge is in manufacturing at low cost in ambient conditions. In order to create light or energy by injecting or collecting electrons, printed electronics require conductors, usually calcium, magnesium or lithium, with a low-work function. These metals are chemically very reactive. They oxidize and stop working if exposed to oxygen and moisture. This is why electronics in solar cells and TVs, for example, must be covered with a rigid, thick barrier such as glass or expensive encapsulation layers.However, in new findings published in the journal Science, Georgia Tech researchers have introduced what appears to be a universal technique to reduce the work function of a conductor. They spread a very thin layer of a polymer, approximately one to 10 nanometers thick, on the conductor's surface to create a strong surface dipole. The interaction turns air-stable conductors into efficient, low-work function electrodes.The commercially available polymers can be easily processed from dilute solutions in solvents such as water and methoxyethanol."These polymers are inexpensive, environmentally friendly and compatible with existent roll-to-roll mass production techniques," said Bernard Kippelen, director of Georgia Tech's Center for Organic Photonics and Electronics (COPE). "Replacing the reactive metals with stable conductors, including conducting polymers, completely changes the requirements of how electronics are manufactured and protected. Their use can pave the way for lower cost and more flexible devices."To illustrate the new method, Kippelen and his peers evaluated the polymers' performance in organic thin-film transistors and OLEDs. They've also built a prototype: the first-ever, completely plastic solar cell."The polymer modifier reduces the work function in a wide range of conductors, including silver, gold and aluminum," noted Seth Marder, associate director of COPE and professor in the School of Chemistry and Biochemistry. "The process is also effective in transparent metal-oxides and graphene."
New Alloy Can Convert Heat Directly Into Electricity By Rebecca Boyle Posted 06.22.2011 at 5:45 pm 35 Comments Multiferroic Material A new multiferroic material begins as a non-magnetic material then suddenly becomes strongly magnetic as the piece of copper below it is heated a small amount. University of Minnesota A new alloy with unique properties can convert heat directly into electricity, according to researchers at the University of Minnesota. The alloy, a multiferroic composite of nickel, cobalt, manganese and tin, can be either non-magnetic and highly magnetic, depending on its temperature.Multiferroic materials possess both magnetism and ferroelectricity, or a permanent electric polarization. Materials with both of these properties are very rare; check out this explainer from the National Institute of Standards and Technology if you’re interested in the electron orbital arrangements that cause these phenomena. In this case, the new alloy — Ni45Co5Mn40Sn10 — undergoes a reversible phase transformation, in which one type of solid turns into another type of solid when the temperature changes, according to a news release from the University of Minnesota. Specifically, the alloy goes from being non-magnetic to highly magnetized. The temperature only needs to be raised a small amount for this to happen.When the warmed alloy is placed near a permanent magnet, like a rare-earth magnet, the alloy’s magnetic force increases suddenly and dramatically. This produces a current in a surrounding coil, according to the researchers, led by aerospace engineering professor Richard James. Watch a piece of the alloy leap over to a permanent magnet in the video clip below.A process called hysteresis causes some of the heat energy to be lost, but this new alloy has a low hysteresis, the researchers say. Because of this, it could be used to convert waste heat energy into large amounts of electricity.One obvious use for this material would be in the exhaust pipes of vehicles. Several automakers are already working on heat transfer devices that can convert a car’s hot exhaust into usable electricity; General Motors is using alloys called skutterudites, which are cobalt-arsenide materials doped with rare earths.Rare earth magnets are already a necessity in many hybrid car batteries, so heat-capture devices made of the new multiferroic compound could be placed near the magnets. The material could also be used in power plants or even ocean thermal energy generators, the researchers said.A paper on the alloy was published in the journal Advanced Energy Materials.
Army Looks to Strike Foes with Lightning WeaponInnovationNewsDaily Staff22 June 2012 01:24 PM ET A guided lightning bolt travels horizontally, then hits a car when it finds the lower resistance path to ground in a U.S. Army test.CREDIT: U.S. Army | Picatinny Arsenal View full size image Today's military lasers can blind spy satellites or burn enemy vehicles, but tomorrow's could guide lightning bolts to strike and destroy battlefield targets.A U.S. Army lab is testing how lasers can create an energized plasma channel in the air — an invisible pathway for electricity to follow. The laser-guided lightning weapon could precisely hit targets such as enemy tanks or unexploded roadside bombs, because such targets represent better conductors for electricity than the ground."We never got tired of the lightning bolts zapping our simulated (targets)," said George Fischer, lead scientist on the project at the U.S. Army's Armament Research, Development and Engineering Center at Picatinny Arsenal in New Jersey. The weapon idea mimics the way that lightning leaps from thunderclouds to strike the ground — the electricity follows the path of least resistance, Fischer explained.Army researchers used an "ultra-short-pulse laser of modest energy" that keeps the laser beam focused through its own intensity. The laser's electro-magnetic field can harvest electrons from air molecules to create the plasma pathway for electricity to follow."During the duration of the laser pulse, it can be putting out more power than a large city needs, but the pulse only lasts for two-trillionths of a second," Fischer said.Such a "laser-induced plasma channel" could also direct high-powered microwave pulses as well as electricity, according to a 2009 Wired article. Microwave pulses have already become weapons in Air Force missiles used to burn out the electronic systems of air defense centers, military jets or drones.Army soldiers may not get to target enemies with Zeus-like lightning bolts anytime soon — the technology remains a lab prototype. But the idea joins a growing arsenal of possible futuristic weapons such as the Navy's railgun superweapon capable of hurling hypersonic projectiles over 50 to 100 miles, or the Army's hypersonic weapon for striking targets anywhere on Earth within an hour.
Printable, Electrically Conductive Gel With Unprecedented Electrical Performance SynthesizedScienceDaily (July 4, 2012) — Stanford researchers have invented an electrically conductive gel that is quick and easy to make, can be patterned onto surfaces with an inkjet printer and demonstrates unprecedented electrical performance.The material, created by Stanford chemical engineering Associate Professor Zhenan Bao, materials science and engineering Associate Professor Yi Cui and members of their labs, is a kind of conducting hydrogel -- a jelly that feels and behaves like biological tissues, but conducts electricity like a metal or semiconductor.That combination of characteristics holds enormous promise for biological sensors and futuristic energy storage devices, but has proven difficult to manufacture until now.The research recently appeared in the journal Proceedings of the National Academy of Sciences.Printing Jell-OBao and Cui made the gel by binding long chains of the organic compound aniline together with phytic acid, found naturally in plant tissues. The acid is able to grab up to six polymer chains at once, making for an extensively cross-linked network."There are already commercially available conducting polymers," said Bao, "but they all form a uniform film without any nanostructures."In contrast, the new gel's cross-linking makes for a complex, sponge-like structure. The hydrogel is marked with innumerable tiny pores that expand the gel's surface area, increasing the amount of charge it can hold, its ability to sense chemicals, and the rapidity of its electrical response.Still, the gel can be easily manipulated. Because the material doesn't solidify until the last step of its synthesis, it can be printed or sprayed as a liquid and turned into a gel after it's already in place -- meaning that manufacturers should be able to construct intricately patterned electrodes at low cost."You can't print Jell-O," said Cui. "But with this technique, we can print it and make it Jell-O later."Soft electrodesThe material's unusual structure also gives the gel what Cui referred to as "remarkable electronic properties."Most hydrogels are tied together by a large number of insulating molecules, reducing the material's overall ability to pass electrical current. But phytic acid is a "small-molecule dopant" -- meaning that when it links polymer chains, it also lends them charge. This effect makes the hydrogel highly conductive.The gel's conductance is "among the best you can get through this kind of process," said Cui. Its capacity to hold charge is very high, and its response to applied charge is unusually fast.The substance's similarity to biological tissues, its large surface area and its electrical capabilities make it well suited for allowing biological systems to communicate with technological hardware.The researchers envision it being used in everything from medical probes and laboratory biological sensors to biofuel cells and high-energy density capacitors."And all it's made of are commercially available ingredients thrown into a water solution," said Bao.The paper's first authors are Guihua Yu, a postdoctoral fellow in chemical engineering at Stanford, and Lijia Pan, a visiting scholar in chemical engineering from Nanjing University, China.Stanford's Precourt Institute for Energy funded the research.
Photovoltaics from Any Semiconductor: Opens Door to More Widespread Solar Energy DevicesScienceDaily (July 26, 2012) — A technology that would enable low-cost, high efficiency solar cells to be made from virtually any semiconductor material has been developed by researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley. This technology opens the door to the use of plentiful, relatively inexpensive semiconductors, such as the promising metal oxides, sulfides and phosphides, that have been considered unsuitable for solar cells because it is so difficult to taylor their properties by chemical means."It's time we put bad materials to good use," says physicist Alex Zettl, who led this research along with colleague Feng Wang. "Our technology allows us to sidestep the difficulty in chemically tailoring many earth abundant, non-toxic semiconductors and instead tailor these materials simply by applying an electric field."Zettl, who holds joint appointments with Berkeley Lab's Materials Sciences Division and UC Berkeley's Physics Department where he directs the Center of Integrated Nanomechanical Systems (COINS), is the corresponding author of a paper describing this work in the journal Nano Letters. The paper is titled "Screening-Engineered Field-Effect Solar Cells." Co-authoring it were William Regan, Steven Byrnes, Will Gannett, Onur Ergen, Oscar Vazquez-Mena and Feng Wang.Solar cells convert sunlight into electricity using semiconductor materials that exhibit the photovoltaic effect -- meaning they absorb photons and release electrons that can be channeled into an electrical current. Photovoltaics are the ultimate source of clean, green and renewable energy but today's technologies utilize relatively scarce and expensive semiconductors, such as large crystals of silicon, or thin films of cadmium telluride or copper indium gallium selenide, that are tricky or expensive to fabricate into devices."Solar technologies today face a cost-to-efficiency trade-off that has slowed widespread implementation," Zettl says. "Our technology reduces the cost and complexity of fabricating solar cells and thereby provides what could be an important cost-effective and environmentally friendly alternative that would accelerate the usage of solar energy."This new technology is called "screening-engineered field-effect photovoltaics," or SFPV, because it utilizes the electric field effect, a well understood phenomenon by which the concentration of charge-carriers in a semiconductor is altered by the application of an electric field. With the SFPV technology, a carefully designed partially screening top electrode lets the gate electric field sufficiently penetrate the electrode and more uniformly modulate the semiconductor carrier concentration and type to induce a p-n junction. This enables the creation of high quality p-n junctions in semiconductors that are difficult if not impossible to dope by conventional chemical methods."Our technology requires only electrode and gate deposition, without the need for high-temperature chemical doping, ion implantation, or other expensive or damaging processes," says lead author William Regan. "The key to our success is the minimal screening of the gate field which is achieved through geometric structuring of the top electrode. This makes it possible for electrical contact to and carrier modulation of the semiconductor to be performed simultaneously."Under the SFPV system, the architecture of the top electrode is structured so that at least one of the electrode's dimensions is confined. In one configuration, working with copper oxide, the Berkeley researchers shaped the electrode contact into narrow fingers; in another configuration, working with silicon, they made the top contact ultra-thin (single layer graphene) across the surface. With sufficiently narrow fingers, the gate field creates a low electrical resistance inversion layer between the fingers and a potential barrier beneath them. A uniformly thin top contact allows gate fields to penetrate and deplete/invert the underlying semiconductor. The results in both configurations are high quality p-n junctions.Says co-author Feng Wang, "Our demonstrations show that a stable, electrically contacted p-n junction can be achieved with nearly any semiconductor and any electrode material through the application of a gate field provided that the electrode is appropriately geometrically structured."The researchers also demonstrated the SFPV effect in a self-gating configuration, in which the gate was powered internally by the electrical activity of the cell itself."The self-gating configuration eliminates the need for an external gate power source, which will simplify the practical implementation of SFPV devices," Regan says. "Additionally, the gate can serve a dual role as an antireflection coating, a feature already common and necessary for high efficiency photovoltaics."
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