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After a 25-year hiatus, the Unites States has produced its first non-weapons grade plutonium needed to power space probes when solar energy won’t suffice.
NASA has been using a radioactive material called plutonium-238 to power its deep space probes since the 1970s. The nuclear-powered spacecraft include the twin Voyager probes, now heading out of the solar system, the Mars Viking landers, the Galileo and Cassini missions at Jupiter and Saturn, respectively, and most recently the Mars Curiosity rover, which is seven months into a planned two-year mission.
The plutonium naturally radiates heat as it decays, which can be converted into electricity with a device known as a radioisotope thermoelectric generator, or RTG. The U.S. produced its own supply of plutonium-238 until the late 1980s, when the Department of Energy’s reactors at the Savannah River Site in South Carolina, where the plutonium was generated, were shut down for safety and environmental issues. NASA then turned to Russia to purchase plutonium, but that supply line dried up in 2010. Since then, the Department of Energy (DOE), working in collaboration with NASA, has been trying to restart domestic production of plutonium-238. Early results are promising. After encapsulating the radioactive starter material neptunium, putting it into a reactor at Oak Ridge National Laboratory in Tennessee and radiating it for a month, the DOE did successfully generate plutonium, said Jim Green, chief of NASA’s planetary science division. “This is a major step forward,” Green said at recent Mars exploration planning group meeting. “We’re expecting reports from (the DOE) later this year on a complete schedule that would then put plutonium on track to be generated at about 1.5 kilograms (3.3 pounds) a year, so it’s going quite well,” Green said. The fresh plutonium has the added benefit of reviving NASA's small and decaying supply of older plutonium still in storage. “It fairly old -- more than 20 years,” Green said, “When we add newly generated plutonium through this process to the older plutonium in a mixture of one new-to-two old units, we can actually revive that and get he energy density we need. So for every 1 kilogram (2.2 pounds), we really revive two other kilograms of the older plutonium by mixing it.” “It’s a critical part of our process to be able to utilize our existing supply at the energy density that we want it at,” he added. Among the upcoming missions that likely will need nuclear power is a follow-on Mars rover based on Curiosity’s design and now-proven sky crane landing system.
Within a nanometer-scale device, visible light travels infinitely fast—by one measure—a team of physicists and engineers reports. The gizmo won't lead to instantaneous communication—the famous speed limit of Albert Einstein's theory of relativity remains in force—but it could have a variety of uses, including serving as an element in a type of optical circuitry. "The demonstration of such a thing is definitely very interesting and possibly useful," says Wenshan Cai, an electrical engineer at the Georgia Institute of Technology in Atlanta, who was not involved in the work. In empty space, light always travels at 300,000,000 meters per second. In a material such as glass, it travels slower. The ratio of light's speed in the vacuum to its speed in a material defines the material's "index of refraction," which is typically greater than one. However, scientists have begun to manipulate the interactions of light and matter to tune the index of refraction in weird ways, such as making it negative, which leads to an unusual bending of light. Now, Albert Polman, a physicist at the FOM Institute for Atomic and Molecular Physics in Amsterdam; Nader Engheta, an electrical engineer at the University of Pennsylvania; and colleagues have pulled off a particularly odd feat. They've developed a tiny device in which the index of refraction for visible light is zero—so that light waves of a particular wavelength move infinitely fast. The device consists of a rectangular bar of insulating silicon dioxide 85 nanometers thick and 2000 nanometers long surrounded by conducing silver, which light generally doesn't penetrate. The result is a light-conveying chamber called a waveguide. Researchers fashioned different devices in which the width of the silicon dioxide ranged from 120 to 400 nanometers. Light behaves differently in such a waveguide, because the electromagnetic fields must obey certain "boundary conditions" on the sides of the device. Short-wavelength light bounces back and forth between the ends of the guide, and the peaks and troughs of the counter-propagating light waves overlap to create a pattern of bright and dark bands much like the pressure patterns with a ringing organ pipe. Above a "cutoff" wavelength, light doesn't flow at all. Right at the cutoff wavelength, things get interesting. Instead of producing a banded pattern, the whole waveguide lights up. That means that instead of acting as waves with equally spaced peaks, or "phase fronts," the wave behaves as if its peaks are moving infinitely fast and are everywhere at once. So the light oscillates in synchrony along the length of the waveguide. Engheta and company had previously created an index of refraction of zero for longer-wavelength radiation called microwaves. Repeating the feat for visible light was harder, as the new widget is too small to contain a light source. Instead, the researchers shot in a beam of electrons to generate light of all wavelengths within the waveguide and measured the light leaking out of it. The amount of light shining out at a particular wavelength depends on whether the electron beam enters at a point where there should be a dark or a bright spot for that wavelength. So by scanning the beam along the waveguide and monitoring the output, researchers traced the light pattern at each wavelength. "It is nanofabrication and characterization at its best," says Che Ting Chan, a physicist at the Hong Kong University of Science and Technology. So how does an everywhere-at-once light wave not violate relativity? Light has two speeds, Engheta explains. The "phase velocity" describes how fast waves of a given wavelength move, and the "group velocity" describes how fast the light conveys energy or information. Only the group velocity must stay below the speed of light in a vacuum, Engheta says, and inside the waveguide, it does. The device could hav e various uses, Engheta says. Because the light leaking out of the waveguide is all in synch, the waveguide might be bent to form an antenna that emits light wave with sculpted phase fronts, he says. It might also make a conduit for a hoped-for type of nanoscale optical circuitry, he says. An array of such waveguides might even make a bulk material with zero index of refraction. But fabricating that array would be very challenging, Cai says: "In theory it's easy; experimentally it's very hard."
It wasn't just £20k bling headphones to be found at the Harrods Technology 2.0 showcase, as Spymaster - best known for its security devices - had something far cooler and far pricier on show: a mock-up of a $2-million private submarine. Yes, you read that right. While many might describe this mini marvel as an overpriced toy, who wouldn't want to go exploring the underwater depths by themselves? It's all very James Bond... or is that more James Cameron? The 22ft-long, 4-tonne Orcasub is built to Lloyd's Register standards and the base model can descend to 1,000ft without a hitch. It's designed to be controlled by joystick and pedals and based on the principles of flight: by using thrust, lift and drag the made-to-order sub can bank, curve and turn much like a private plane. The battery-powered Orcasub comes with 80 hours of life support in each of its two 360-degree open-view pods, has multi-beam collision-avoidance sonar so you know what's going on around you, a digital long-range underwater communication system to keep in contact with the world above and a 60,000 lumen Nuytco NewtSun ultra-LED lighting system to light up the surrounding water. Although we doubt that the muddied waters of Margate will be all too appealing to prospective buyers, the Orcasub sure does sound like the ultimate gadget - if it can even be called that - for those beautiful, clear waters of the world. You know, the kind of places where the rich own their own private islands and, in the not too distant future, their own private submarines too. If 2,000ft isn't deep enough for your likes then prepare to delve deeper into the abyss of those apparently bottomless pockets: varying depth-capable productions are available to order, maxing out at the $9.32-million version that can descend to 6,000ft. Spymaster will throw in five day's training into the price which, given the multimillion-dollar cost price, seems, we suppose, fairly reasonable. Now all we just need is for Spymaster to team up with Lotus to make that ultimate fantasy car-meets-sub a reality so the mega rich can play out theirJames Bond dreams like never before.
Researchers at Brown University have succeeded in creating the first wireless, implantable, rechargeable, long-term brain-computer interface. The wireless BCIs have been implanted in pigs and monkeys for over 13 months without issue, and human subjects are next. A tether limits the mobility of the patient, and also the real-world testing that can be performed by the researchers. Brown’s wireless BCI allows the subject to move freely, dramatically increasing the quantity and quality of data that can be gathered — instead of watching what happens when a monkey moves its arm, scientists can now analyze its brain activity during complex activity, such as foraging or social interaction. Obviously, once the wireless implant is approved for human testing, being able to move freely — rather than strapped to a chair in the lab — would be rather empowering. Inside the device, there’s a li-ion battery, an inductive (wireless) charging loop, a chip that digitizes the signals from your brain, and an antenna for transmitting those neural spikes to a nearby computer. The BCI is connected to a small chip with 100 electrodes protruding from it, which, in this study, was embedded in the somatosensory cortex or motor cortex. These 100 electrodes produce a lot of data, which the BCI transmits at 24Mbps over the 3.2 and 3.8GHz bands to a receiver that is one meter away. The BCI’s battery takes two hours to charge via wireless inductive charging, and then has enough juice to last for six hours of use.
One of the features that the Brown researchers seem most excited about is the device’s power consumption, which is just 100 milliwatts. For a device that might eventually find its way into humans, frugal power consumption is a key factor that will enable all-day, highly mobile usage. Amusingly, though, the research paper notes that the wireless charging does cause significant warming of the device, which was “mitigated by liquid cooling the area with chilled water during the recharge process and did not notably affect the animal’s comfort.” Another important factor is that the researchers were able to extract high-quality, “rich” neural signals from the wireless implant — a good indicator that it will also help human neuroscience, if and when the device is approved.
A revolutionary liquid-cooled computer server that could slash the carbon footprint of the internet is being tested at the University of Leeds. While most computers use air to cool their electronics, all of the components in the new server are completely immersed in liquid. The power-hungry fans of traditional computing are replaced by a silent next-generation liquid cooling process that relies on the natural convection of heat. But the significance of the new Iceotope server lies less in the novelty of its design than in the bite it could take out of the huge electricity demands of the internet servers that form the fabric of our online lives. Its designers calculate that the server cuts energy consumption for cooling by between 80 percent and 97 percent. While the information industry enjoys an image of hyper efficiency and environmental friendliness, all internet use relies on remote servers, which are usually housed in large data centres that must be constantly cooled to remain operational. The reality is that the mobile apps, networked devices and 24-hour internet access on which we have come to rely are very energy hungry. A 2011 report by Datacenter Dynamics estimated that the world’s data centres currently use 31 gigawatts of power, the equivalent of about half of the UK’s total peak electricity demand. A 2008 report by McKinsey and Company projected that data centre carbon emissions will quadruple by 2020 and a year-long investigation by the New York Times, published in September, criticized the industry for its energy waste.
Firefighters put their lives on the line in some of the most dangerous conditions on Earth. One of their greatest challenges, however, is seeing through thick veils of smoke and walls of flame to find people in need of rescue. A team of Italian researchers has developed a new imaging technique that uses infrared (IR) digital holography to peer through chaotic conflagrations and capture potentially lifesaving and otherwise hidden details. The team describes its breakthrough results and their applications in a paper published today in the Optical Society’s (OSA) open-access journal Optics Express.
Firefighters can see through smoke using current IR camera technology. However, such instruments are blinded by the intense infrared radiation emitted by flames, which overwhelm the sensitive detectors and limit their use in the field. By employing a specialized lens-free technique, the researchers have created a system that is able to cope with the flood of radiation from an environment filled with flames as well as smoke.
“IR cameras cannot ‘see’ objects or humans behind flames because of the need for a zoom lens that concentrates the rays on the sensor to form the image,” says Pietro Ferraro of the Consiglio Nazionale delle Ricerche (CNR) Istituto Nazionale di Ottica in Italy. By eliminating the need for the zoom lens, the new technique avoids this drawback.
“It became clear to us that we had in our hands a technology that could be exploited by emergency responders and firefighters at a fire scene to see through smoke without being blinded by flames, a limitation of existing technology,” Ferraro says. “Perhaps most importantly, we demonstrated for the first time that a holographic recording of a live person can be achieved even while the body is moving.”
Holography is a means of producing a 3-D image of an object. To create a hologram, such as those typically seen on credit cards, a laser beam is split into two (an object beam and a reference beam). The object beam is shone onto the object being imaged. When the reflected object beam and the reference beam are recombined, they create an interference pattern that encodes the 3-D image.
In the researchers’ new imaging system, a beam of infrared laser light is widely dispersed throughout a room. Unlike visible light, which cannot penetrate thick smoke and flames, the IR rays pass through largely unhindered. The IR light does, however, reflect off of any objects or people in the room, and the information carried by this reflected light is recorded by a holographic imager. It is then decoded to reveal the objects beyond the smoke and flames. The result is a live, 3-D movie of the room and its contents.
The internet connects people all over the world. But could the internet also connect us with dolphins, apes, elephants and other highly intelligent species? In a bold talk in Session 10 of TED2013, four incredible thinkers come together to launch the idea of the interspecies internet. Each takes four minutes to talk, then passes the metaphorical baton, building the narrative in parts. The talk begins with Diana Reiss, a cognitive psychologist who studies intelligence in animals. She shows us a video of an adorable dolphin twirling in the water. But the dolphin isn’t spinning playfully for the camera — the dolphin is watching itself in a two-way mirror. “A dolphin has self-awareness,” says Reiss. “We used to think this was a uniquely human quality, but dolphins aren’t the only non-human animals to show self-recognition in a mirror. Great apes, our closest relatives, also show this ability.” Ditto for elephants and even magpies. Reiss shares her work with dolphins — she’s been teaching them to communicate through an underwater keyboard of symbols that correspond to whistles and playful activities. Through this keyboard, the dolphins learned to perform activities on demand, and also to express their desire for them.
Researchers at The Ohio State University (OSU) have successfully completed more than 200 hours of continuous operation of their patented Coal-Direct Chemical Looping (CDCL) technology - a one-step process to produce both electric power and high-purity carbon dioxide (CO2). The test, led by OSU Professor Liang-Shih Fan, represents the longest integrated operation of chemical looping technology anywhere in the world to date. The test was conducted at OSU’s 25 kilowatt thermal (kWt) CDCL combustion sub-pilot unit under the auspices of DOE’s Carbon Capture Program, which is developing innovative environmental control technologies to foster the use of the nation’s vast coal reserves. Managed by the Office of Fossil Energy’s National Energy Technology Laboratory, the program’s specific goal is to develop CO2 capture and compression technologies that can reduce the capital cost and energy penalty of CO2 capture by more than half—equivalent to CO2 capture at less than $40 per metric ton—when integrated into a new or existing coal fired power plant. The successful test moves chemical-looping a step closer to full scale. Chemical looping is an advanced technology that offers several advantages over traditional combustion. In a chemical-looping system, a metal oxide, such as an iron oxide, provides the oxygen for combustion. The metal oxide releases its oxygen in a fuel reactor with a reducing atmosphere, and the oxygen reacts with the fuel. The reduced metal cycles back to an oxidation chamber where the metal oxide is regenerated by contact with air. The metal oxide is then reintroduced into the fuel reactor, thus completing the loop. Since CO2 separation occurs simultaneously with coal conversion, chemical looping offers a low-cost scheme for carbon capture. The process can produce power, synthesis gas, or hydrogen in addition to high-purity CO2. OSU reports that the CDCL plant’s 200+ hours of operation, using metallurgical coke and subbituminous and lignite coals, shows the robustness of its novel moving-bed design and non-mechanical valve operation. The combination resulted in nearly 100 percent solid fuel conversion and a CO2 stream more than 99 percent pure, making it applicable to CO2 enhanced oil recovery operations. The OSU project is expected to benefit the DOE Carbon Capture Program by identifying oxygen carriers and a chemical looping process having the potential to control multiple pollutants, including sulfur dioxide (SO2) and nitrogen oxides (NOx), along with CO2. OSU research aims to identify potential barriers and optimize the CDCL technology and provide realistic data for future technological and economic analysis.
Transparent solar panels -- think about it for a moment: Sheets of glass or transparent plastic films that also generate electricity. The concept of transparent solar panels isn’t new, of course, but it now looks like they’re finally finding their way to market: Ubiquitous Energy, a startup that was spun off from MIT last year, is developing a technology and patent portfolio and hopes to bring affordable transparent solar panels to market soon. At this point, you might be wondering how transparent solar cells actually work — after all, if it’s transparent, how can it absorb light energy? The simple answer is that light energy comes in many frequencies (colors), but as far as we humans are concerned, it is only the visible wavelengths — from blue, through green and yellow, to red — that really matter. The Sun, however, pumps out a huge amount of infrared light, and some ultraviolet light — both of which are invisible to the human eye, but which can also generate large amounts of electricity if captured by a solar cell. The trick, then, is creating a solar cell that only absorbs IR and UV radiation, while letting visible light pass straight through. According to Technology Review, Ubiquitous Energy’s transparent solar cell is built up from a series of organic layers on glass or a flexible film. We don’t know the exact nature of the organic materials being used, but other organic solar cells generally use organic polymers that might’ve had their molecular makeup altered to absorb specific wavelengths of light. There are other ways of building transparent solar cells, though: As we reported last year, researchers at UCLA and UC Santa Barbara made a flexible, high-efficiency cell from a mesh of transparent, photovoltaic silver nanowires.
A quantum computer doesn't need to be a single large device but could be built from a network of small parts, new research from the University of Bristol has demonstrated. As a result, building such a computer would be easier to achieve.
Many groups of research scientists around the world are trying to build a quantum computer to run algorithms that take advantage of the strange effects of quantum mechanics such as entanglement and superposition. A quantum computer could solve problems in chemistry by simulating many body quantum systems, or break modern cryptographic schemes by quickly factorising large numbers.
Previous research shows that if a quantum algorithm is to offer an exponential speed-up over classical computing, there must be a large entangled state at some point in the computation and it was widely believed that this translates into requiring a single large device.
In a paper published in the Proceedings of the Royal Society A, Dr Steve Brierley of Bristol's School of Mathematics and colleagues show that, in fact, this is not the case. A network of small quantum computers can implement any quantum algorithm with a small overhead.
The key breakthrough was learning how to efficiently move quantum data between the many sites without causing a collision or destroying the delicate superposition needed in the computation. This allows the different sites to communicate with each other during the computation in much the same way a parallel classical computer would do.
McLaughlin Crater is 90.92 km (56.50 mi) in diameter and 2.2 km (1.4 mi) deep with a floor that is well below Martian “sealevel” and contains clays that bear iron and magnesium as well as carbonate. By the time eukaryotic life or photosynthesis evolved on Earth, the martian surface had become extremely inhospitable, but the subsurface of Mars could potentially have contained a vast microbial biosphere. Crustal fluids may have welled up from the subsurface to alter and cement surface sediments, potentially preserving clues to subsurface habitability. Many ancient, deep basins lack evidence for groundwater activity. However, McLaughlin Crater, one of the deepest craters on Mars, contains evidence for Mg–Fe-bearing clays and carbonates that probably formed in an alkaline, groundwater-fed lacustrine setting. This environment strongly contrasts with the acidic, water-limited environments implied by the presence of sulphate deposits that have previously been suggested to form owing to groundwater upwelling. Deposits formed as a result of groundwater upwelling on Mars, such as those in McLaughlin Crater, could preserve critical evidence of a deep biosphere on Mars. Scientists suggest that groundwater upwelling on Mars may have occurred sporadically on local scales, rather than at regional or global scales. “This environment strongly contrasts with the acidic, water-limited environments implied by the presence of sulphate deposits that have previously been suggested to form owing to groundwater upwelling.” Water-made channels which are now dry, appear to flow down the walls of McLaughlin Crater and stop well above the crater floor, which indicates they once provided water to a lake. “The deposits in McLaughlin Crater could have very high preservation potential for organic materials, in much the same manner as turbidites do on Earth.” Cyanobacteria, which are common in alkaline lakes on Earth may have aided in the formation of carbonate minerals in lakes such as the McLAughlin Crater on Mars. Sometimes these bacteria become form microscopic fossils. If similar conditions existed in the craters ancient alkaline lake fossils of micro-organisms may still be there awaiting us.
Temporary electronic tattoos could soon help people fly drones with only thought and talk seemingly telepathically without speech over smartphones, researchers say. Commanding machines using the brain is no longer the stuff of science fiction. In recent years, brain implants have enabled people to control robotics using only their minds, raising the prospect that one day patients could overcome disabilities using bionic limbs or mechanical exoskeletons. But brain implants are invasive technologies, probably of use only to people in medical need of them. Instead, electrical engineer Todd Coleman at the University of California at San Diego is devising noninvasive means of controlling machines via the mind, techniques virtually everyone might be able to use. His team is developing wireless flexible electronics one can apply on the forehead just like temporary tattoos to read brain activity. “We want something we can use in the coffee shop to have fun,” Coleman says. The devices are less than 100 microns thick, the average diameter of a human hair. They consist of circuitry embedded in a layer or rubbery polyester that allow them to stretch, bend and wrinkle. They are barely visible when placed on skin, making them easy to conceal from others. The devices can detect electrical signals linked with brain waves, and incorporate solar cells for power and antennas that allow them to communicate wirelessly or receive energy. Other elements can be added as well, like thermal sensors to monitor skin temperature and light detectors to analyze blood oxygen levels. Using the electronic tattoos, Coleman and his colleagues have found they can detect brain signals reflective of mental states, such as recognition of familiar images. One application they are now pursuing is monitoring premature babies to detect the onset of seizures that can lead to epilepsy or brain development problems. The devices are now being commercialized for use as consumer, digital health, medical device, and industrial and defense products by startup MC10 in Cambridge, Mass.
German and Hungarian researchers have brought sight to nine blind patients with hereditary retinal degeneration, using a subretinally implanted microelectronic chip with 1500 pixels. The chip size is approximately 3mm x 3mm and is surgically implanted below the fovea (area of sharpest vision in the retina). It provides a diamond-shaped visual field of 15 degrees diagonally across chip corners. It is powered by a subdermal coil behind the ear that is powered from a battery via transdermal inductive transmission. The core of the implant is a microchip with 1,500 pixels, each 70 x 70 microns. Photocells, an amplifying circuit, and a stimulation electrode are attached to each pixel. The photocells absorb the light entering the eye, transforming it into electrical signals. A tiny power line provides energy from the subdermal coil Sixteen additional electrodes are placed for testing purposes at the tip of the implant. The incoming light intensity controls the amount of current released by each electrode, stimulating the neighboring intact retinal nerve cells electrically. The nerve impulses generated by the retinal cells are processed in the remaining neuronal network of the retina and transmitted via the optic nerve to the visual cortex, creating visual sensations. An unimpaired, regularly functioning optic nerve is required.
“So far, our approach using subretinal electronic implants is the only one that has successfully mediated images in a trial with freely moving blind persons by means of a light sensor array that moves with the eye,” the scientists said. “All the other current approaches require an extraocular camera that does not link image capture to eye movements, which, therefore, does not allow the utilization of microsaccades for refreshing the perceived images.” In most hereditary retinal diseases, such as retinitis pigmentosa, the photoreceptors progressively degenerate, often causing blindness in adult life, and there is no therapy available to treat this disease.
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Researchers at the University of California, Berkeley have created the first ever graphene audio speaker: an earphone. In its raw state, without any kind of optimization, the researchers show that graphene’s superior physical and electrical properties allow for an earphone with frequency response comparable to or better than a pair of commercial Sennheiser earphones. A loudspeaker (or earphone or headphone) works by vibrating a (usually) paper diaphragm (aka a cone), creating pressure waves in the air around you. Depending on the frequency of these waves, different sounds are created. Human ears, depending on their age, can usually hear frequencies between 20Hz (very low pitch) and 20KHz (very high). Generally, the quality of a speaker is defined by how flat its frequency response is — in other words, whether it produces sounds equally well, no matter where they fall on the 20Hz to 20KHz scale. A poor speaker, or, say, a bassy set of headphones, might be very strong in the lower ranges, but weaker at the top. In Berkeley’s graphene earphone, the diaphragm is made from a 30nm-thick, 7mm-wide sheet of graphene. This diaphragm is then sandwiched between two silicon electrodes, which are coated with silicon dioxide to prevent any shorting if the diaphragm is driven too hard. By applying power to the electrodes, an electrostatic force is created, which causes the graphene diaphragm to vibrate, creating sound. By oscillating the electricity, different sounds are created.
Given graphene’s status as a wonder material we shouldn’t really be surprised, but it turns out that this graphene speaker — the first of its kind — has intrinsically excellent performance. As you can see in the graph above, the graphene earphone’s frequency response is superb. The reason for this is down to the graphene diaphragm’s simplicity: Whereas most diaphragms/cones must be damped (padded, restricted) to prevent undesirable frequency responses, the graphene diaphragm requires no damping. This is because graphene is so strong that the diaphragm can be incredibly thin — and thus very light. Instead of being artificially damped, the graphene diaphragm is damped by air itself. As a corollary, the lack of damping means that the graphene diaphragm is also very energy efficient — which could be important for reducing the power usage of smartphone and tablet speakers.
It was incredible the first time the system kicked in and healed itself. It felt like we were witnessing the next step in the evolution of integrated circuits," says Ali Hajimiri, professor of electrical engineering at Caltech. "We had literally just blasted half the amplifier and vaporized many of its components, such as transistors, and it was able to recover to nearly its ideal performance."
Imagine if the chips in your phone or computer could fix themselves almost instantly from problems such as battery power loss and transistor failure. It might sound like the stuff of science fiction, but a team of engineers at the California Institute of Technology (Caltech), for the first time ever, has developed just such self-healing integrated chips. The team demonstrated this self-healing capability in tiny power amplifiers. The amplifiers are so small that 76 of the chips—including everything they need to self-heal—could fit on a single penny. In perhaps the most dramatic of their experiments, the team destroyed various parts of their chips by zapping them multiple times with a high-power laser, and then observed as the chips automatically developed a work-around in less than a second. Until now, even a single fault has often rendered an integrated-circuit chip completely useless. The engineers wanted to give integrated-circuit chips a healing ability akin to that of our own immune system—something capable of detecting and quickly responding to any number of possible assaults in order to keep the larger system working optimally. The power amplifier they devised employs a multitude of robust, on-chip sensors that monitor temperature, current, voltage, and power. The information from those sensors feeds into a custom-made application-specific integrated-circuit (ASIC) unit on the same chip, a central processor that acts as the “brain” of the system. The brain analyzes the amplifier’s overall performance and determines if it needs to adjust any of the system’s actuators—the changeable parts of the chip. Interestingly, the chip’s brain does not operate based on algorithms that know how to respond to every possible scenario. Instead, it draws conclusions based on the aggregate response of the sensors. “You tell the chip the results you want and let it figure out how to produce those results,” says Steven Bowers, a graduate student in Hajimiri’s lab and lead author of the new paper. “The challenge is that there are more than 100,000 transistors on each chip. We don’t know all of the different things that might go wrong, and we don’t need to. World of possibilities: The team chose to demonstrate this self-healing capability first in a power amplifier for millimeter-wave frequencies. Such high-frequency integrated chips are at the cutting edge of research and are useful for next-generation communications, imaging, sensing, and radar applications. By showing that the self-healing capability works well in such an advanced system, the researchers hope to show that the self-healing approach can be extended to virtually any other electronic system. “Bringing this type of electronic immune system to integrated-circuit chips opens up a world of possibilities,” says Hajimiri. “It is truly a shift in the way we view circuits and their ability to operate independently. They can now both diagnose and fix their own problems without any human intervention, moving one step closer to indestructible circuits.”
Want to wirelessly upload hundreds of movies to a mobile device in a few seconds? Researchers at Georgia Tech have drawn up blueprints for a wireless antenna made from atom-thin sheets of carbon, or graphene, that could allow terabit-per-second transfer speeds at short ranges. “It’s a gigantic volume of bandwidth. Nowadays, if you try to copy everything from one computer to another wirelessly, it takes hours. If you have this, you can do everything in one second—boom,” says Ian Akyildiz, director of the broadband wireless networking laboratory at Georgia Tech. A terabit per second could be done at a range of about one meter using a graphene antenna, which would make it possible to obtain 10 high-definition movies by waving your phone past another device for one second. Akyildiz and colleagues have also calculated that at even shorter ranges, such as a few centimeters, data rates of up to 100 terabits per second are theoretically possible. Graphene is a sheet of carbon just one atom thick, in a honeycomb structure, and it has many desirable electronic properties. Electrons move through graphene with virtually no resistance—50 to 500 times faster than they do in silicon. To make an antenna, the group says, graphene could be shaped into narrow strips of between 10 and 100 nanometers wide and one micrometer long, allowing it to transmit and receive at the terahertz frequency, which roughly corresponds to those size scales. Electromagnetic waves in the terahertz frequency would then interact with plasmonic waves—oscillations of electrons at the surface of the graphene strip—to send and receive information. “This points out and provides a set of classical calculations on estimates of sizes and performance: it points out that there is something worthwhile here,” says Phaedon Avouris, an IBM fellow who leads graphene and other nanometer-scale technology at IBM Research in Yorktown Heights, New York. “It doesn’t solve the whole problem, but points out an opportunity.” As well as facilitating high-speed communication between devices, graphene antennas could enable faster wireless connections between nanoscale components on chips. “Antennas made of graphene can be made much smaller in all dimensions than a metal wire antenna. It can be made to be on the order of a micrometer or a few nanometers,” Avouris says. “The significance is that the antenna can be incorporated in a very small object.” Of course, myriad challenges lie ahead. Antennas don’t work alone; they rely on many other components—such as signal generators and detectors, amplifiers, and filters—all of which would have to be fabricated at similar scales and with similar speeds in order to make a complete device. Researchers also need to work out how to do the manufacturing. Working with the material is extremely tricky, because its properties change when it comes in contact with other materials. However, the Georgia Tech group hopes to make a prototype of an antenna within a year, Akyildiz added, and other components after that.
The world of rechargeable batteries is full of trade-offs. While lithium-ion (Li-ion) batteries are currently the most commercially successful, their low energy density doesn't allow for a long driving range. They are also very expensive, often accounting for half the price of electric vehicles. One alternative is lithium-sulfur (Li-S) batteries, which are attractive for their high gravimetric energy density that allows them to store more energy than Li-ion batteries. And although they still use some lithium, the sulfur component allows them to be much cheaper than Li-ion batteries. But one of the biggest drawbacks of Li-S batteries is their short cycle life, which causes them to lose much of their capacity every time they are recharged.
Now a team of researchers led by Yi Cui, a professor of materials science and engineering at Stanford University, has developed a Li-S battery that can retain more than 80% of its 1180 mAh/g capacity over 300 cycles, with the potential for similar capacity retention over thousands of cycles. In contrast, most Li-S batteries lose much of their capacity after a few tens of cycles. To achieve this improvement, the researchers first identified a new mechanism that causes capacity decay in Li-S batteries after cycling. In order for a Li-S battery to successfully recharge, the lithium sulfide in the cathode must be bound to the cathode surface—in this case, the inner surface of the hollow carbon nanofiber that encapsulates it. This binding creates a good electrical contact to allow for charge flow. But the researchers found that, during the discharge process, the lithium sulfide detaches from the carbon, resulting in a loss of electrical contact that prevents the battery from fully recharging. After identifying the problem, the researchers set about fixing it by adding polymers to the carbon nanofiber surface in order to modify the carbon-sulfur interface. The polymers are amphiphilic, meaning they are both hydrophilic (water-loving) and lipophilic (fat-loving), similar to soap. This property gives the polymers anchoring points that allow the lithium sulfides to bind strongly with the carbon surface in order to maintain strong electrical contacts. As experiments showed, sulfur cathodes containing the amphiphilic polymers had very stable performance, with less than 3% capacity decay over the first 100 cycles, and less than 20% decay for more than 300 cycles. Although the improvement is a big step forward, the capacity retention still doesn't compare to Li-ion batteries, some of which have lifespans approaching 10,000 cycles. In order to avoid having to replace the battery every few years, electric vehicles require these longer lifespans. But Cui says that Li-S batteries have the potential to close this gap in the foreseeable future. "Using the amphiphilic polymer idea here in this paper, together with nanoscale materials design and synthesis, it is possible to improve the cycle life up to 10,000 cycles," Cui told Phys.org. "My group is working on this. Our recent results on nanomaterials design already improved to 1000 cycles." In the future, Cui think Li-S batteries will give Li-ion batteries some serious competition. "The Li-S batteries become pretty promising for electric vehicles," he said. "The life cycle needs to improve further. The lithium metal anodes' safety problem needs to be solved. It is possible to get around Li metal anodes with Si anodes."
The world should unite to establish a defense system against space objects that threaten Earth, Russian Deputy Prime Minister Dmitry Rogozin says. Rogozin, speaking Saturday at a ceremony marking Defender of the Fatherland Day in the Moscow suburb of Krasnogorsk, told members of his Rodina Party the effort should be undertaken under the umbrella of the United Nations, RIA Novosti reported. The Russian leader said the threat from asteroids, meteorites, comets and other stray space objects should serve to "unite humanity in the face of a common enemy." "This system should become global and universal in its technical and political sense and is a matter of agreement in the framework of the United Nations," Rogozin said. The call came as Russia is recovering from a Feb. 15 meteorite strike near Chelyabinsk in the Ural Mountains region that created a massive shock, blowing out windows, damaging thousands of buildings and injuring 1,200 people, mainly from flying glass. More than 50 people were hospitalized and damage from the shock wave has been estimated at $33 million. Creating an effective protection against stray space objects is a task that no country, including the United States, would be able to be able to cope with alone, Rogozin said, asserting that no one system of aerospace defense on the planet could handle the threat. The problem with current anti-missile systems and other aerospace defense technologies is that they're designed to track incoming objects launched from the ground, rather than those coming from space, Rogozin said. To protect against such "cosmic enemies," he said, the world would need a system able to recognize the risk in advance. "The great space powers, including Russia, could make in-kind contributions with the technology and programs that have already been established," he said. "We need to find such technical decisions, which we don't have now, such capabilities which could change the flight path of a dangerous space object at a long distance from the Earth or destroy it." However, Rogozin added, if such a worldwide anti-asteroid system were to be established, some countries could use it as a pretext to deploy nuclear weapons in space, Interfax reported. "An undesirable effect of this might be that, under the guise of countering asteroids, some countries, which I prefer not to name, might use this as a pretext for deploying nuclear weapons in outer space," he said. Alexander Bagrov, a senior researcher at the Institute of Astronomy of the Russian Academy of Sciences, told the Voice of Russia such a worldwide defense system against space objects can be created.
The DARPA Tactical Technology Office is soliciting proposals on the design, development and demonstration of a vertical takeoff and landing (VTOL) experimental aircraft (X-Plane) with exceptional performance in vertical and cruise flight, and operational capability through transition from vertical to forward flight Higher speeds, increased efficiency, elegant designs are the focus of DARPA’s new VTOL X-Plane. The versatility of helicopters and other vertical take-off and landing (VTOL) aircraft make them ideal for a host of military operations.
Helicopters are slower — leaving them more vulnerable to damage from enemy weapons. Special operations that rely on lightning-quick strikes and medical units that transport patients to care facilities need enhanced speed to shorten mission times, increase mission range, reduce the number of refueling events and, most important, reduce exposure to the adversary. However, “for the past 50 years, we have seen jets go higher and faster while VTOL aircraft speeds have flat-lined and designs have become increasingly complex,” saidAshish Bagai, DARPA program manager. “To overcome this problem, DARPA has launched the VTOL X-Plane program to challenge industry and innovative engineers to concurrently push the envelope in four areas: speed, hover efficiency, cruise efficiency and useful load capacity.” “We have not made this easy,” he continued. “Strapping rockets onto the back of a helicopter is not the type of approach we’re looking for. The engineering community is familiar with the numerous attempts in the past that have not worked. This time, rather than tweaking past designs, we are looking for true cross-pollinations of designs and technologies from the fixed-wing and rotary-wing worlds. The elegant confluence of these engineering design paradigms is where this program should find some interesting results.”
Northwestern University’s Yonggang Huang and the University of Illinois’ John A. Rogers are the first to demonstrate a stretchable lithium-ion battery -- a flexible device capable of powering their innovative stretchable electronics. No longer needing to be connected by a cord to an electrical outlet, the stretchable electronic devices now could be used anywhere, including inside the human body. The implantable electronics could monitor anything from brain waves to heart activity, succeeding where flat, rigid batteries would fail. Huang and Rogers have demonstrated a battery that continues to work -- powering a commercial light-emitting diode (LED) -- even when stretched, folded, twisted and mounted on a human elbow. The battery can work for eight to nine hours before it needs recharging, which can be done wirelessly. The new battery enables true integration of electronics and power into a small, stretchable package. Huang and Rogers have been working together for the last six years on stretchable electronics, and designing a cordless power supply has been a major challenge. Now they have solved the problem with their clever “space filling technique,” which delivers a small, high-powered battery. For their stretchable electronic circuits, the two developed “pop-up” technology that allows circuits to bend, stretch and twist. They created an array of tiny circuit elements connected by metal wire “pop-up bridges.” When the array is stretched, the wires -- not the rigid circuits -- pop up. This approach works for circuits but not for a stretchable battery. A lot of space is needed in between components for the “pop-up” interconnect to work. Circuits can be spaced out enough in an array, but battery components must be packed tightly to produce a powerful but small battery. There is not enough space between battery components for the “pop-up” technology to work. Huang’s design solution is to use metal wire interconnects that are long, wavy lines, filling the small space between battery components. The power travels through the interconnects. The unique mechanism is a “spring within a spring”: The line connecting the components is a large “S” shape and within that “S” are many smaller “S’s.” When the battery is stretched, the large “S” first stretches out and disappears, leaving a line of small squiggles. The stretching continues, with the small squiggles disappearing as the interconnect between electrodes becomes taut. “We call this ordered unraveling,” Huang said. “And this is how we can produce a battery that stretches up to 300 percent of its original size.” The stretching process is reversible, and the battery can be recharged wirelessly. The battery’s design allows for the integration of stretchable, inductive coils to enable charging through an external source but without the need for a physical connection. Huang, Rogers and their teams found the battery capable of 20 cycles of recharging with little loss in capacity. The system they report in the paper consists of a square array of 100 electrode disks, electrically connected in parallel.
The team created rainfall maps for the whole of the Netherlands by using data from a mobile network in the country. This was based on measurements of the attenuation of microwave signal levels across 2400 network links over a four-month period. The resulting maps had a strong correlation with the same measurements taken by the conventional techniques of weather radar and rain gauges. The research was carried out by Aart Overeem and colleagues, from both Wageningen University and the Royal Netherlands Meteorological Institute. "Microwave links are used in telecommunication networks to transmit signals from the antenna of one telephone tower to the antenna of another telephone tower," said Overeem, who led the study. "When it rains the signal is attenuated, which is noticed as a decrease of the received power measured by these telephone towers. The average rainfall intensity...can be computed from the decrease in power during rainy periods with respect to the power during dry periods." The team looked at the minimum and maximum received signal power at each telephone tower over 15 minute periods. Passing through falling raindrops absorbs part of the incident microwave transmission and causes minor beam scattering, lowering the power that ultimately reaches the receiving tower. The more raindrops in the beam's path – or the larger the drops are – the more signal power is lost. By comparing received powers for each network link with reference values for known dry periods – and factoring in accounts for humidity and the water films that can develop on the communications antennae – rainfall densities along each path can be calculated. These values are then treated as point measurements at the centre of each network link and used to extrapolate the larger rain distribution maps. In the frequencies employed in these links, attenuation caused by raindrops is the main source of power reductions, beyond free space losses. Typically, the microwave network links operate at least 10 m off the ground and use frequencies between 13 and 40 GHz.
Astronomers trace the origin of a meteor that injured about 1,000 people after breaking up over central Russia earlier this month. Using the footage and the location of an impact into Lake Chebarkul, Jorge Zuluaga and Ignacio Ferrin, from the University of Antioquia in Medellin were able to use simple trigonometry to calculate the height, speed and position of the rock as it fell to Earth. To reconstruct the meteor's original orbit around the Sun, they used six different properties of its trajectory through Earth's atmosphere. Most of these are related to the point at which the meteor becomes bright enough to cast a noticeable shadow in the videos. The Chelyabinsk meteor (labelled ChM) appears to have been on elliptical orbit around the Sun before it collided with Earth. The researchers then plugged their figures into astronomy software developed by the US Naval Observatory. The results suggest the meteor belongs to a well known family of space rocks - known as the Apollo asteroids - that cross Earth's orbit. Of about 9,700 near-Earth asteroids discovered so far, about 5,200 are thought to be Apollos. Asteroids are divided into different groups such as Apollo, Aten, or Amor, based on the type of orbit they have. D.r Stephen Lowry, from the University of Kent, said the team had done well to publish so quickly. "It certainly looks like it was a member of the Apollo class of asteroids," he told said. "Its elliptical, low inclination orbit, indicates a solar system origin, most likely from the asteroid belt between Mars and Jupiter. Dr. Lowry added: "Perhaps with more data, we can determine roughly where in the asteroid belt it come from."
A new discovery by researchers at the ICFO has revealed that graphene is even more efficient at converting light into electricity than previously known. Graphene is capable of converting a single photon of light into multiple electrons able to drive electric current. The discovery is an important one for next-generation solar cells, as well as other light-detecting and light-harvesting technologies. A paradigm shift in the materials industry is likely within the near-future as a variety of unique materials replaces those that we commonly use today, such as plastics. Among these new materials, graphene stands out. The single-atom-thick sheet of pure carbon has an enormous number of potential applications across a variety of fields. Its potential use in high-efficiency, flexible, and transparent solar cells is among the potential applications. Some of the other most discussed applications include: foldable batteries/cellphones/computers, extremely thin computers/displays, desalination and water purificationtechnology, fuel distillation, integrated circuits, single-molecule gas sensors, etc.
A new video standard enables a fourfold increase in the resolution of TV screens, and an MIT chip was the first to handle it in real time. It took only a few years for high-definition televisions to make the transition from high-priced novelty to ubiquitous commodity — and they now seem to be heading for obsolescence just as quickly. At the Consumer Electronics Show (CES) in January, several manufacturers debuted new ultrahigh-definition, or UHD, models (also known as 4K or Quad HD) with four times the resolution of today’s HD TVs.
In addition to screens with four times the pixels, however, UHD also requires a new video-coding standard, known as high-efficiency video coding, or HEVC. Also at CES, Broadcom announced the first commercial HEVC chip, which it said will go into volume production in mid-2014.
At the International Solid-State Circuits Conference this week, MIT researchers unveiled their own HEVC chip. The researchers’ design was executed by the Taiwan Semiconductor Manufacturing Company, through its University Shuttle Program, and Texas Instruments (TI) funded the chip's development.
Although the MIT chip isn’t intended for commercial release, its developers believe that the challenge of implementing HEVC algorithms in silicon helps illustrate design principles that could be broadly useful. Moreover, “because now we have the chip with us, it is now possible for us to figure out ways in which different types of video data actually interact with hardware,” says Mehul Tikekar, an MIT graduate student in electrical engineering and computer science and one of the paper's co-authors.
A new method of capturing images based on a flat, flexible, transparent, and potentially disposable polymer sheet has been developed by a team of researchers at Johannes Kepler University Linz in Austria. The new imager, which resembles a flexible plastic film, uses fluorescent particles to capture incoming light and channel a portion of it to an array of sensors framing the sheet. With no electronics or internal components, the imager’s simple design makes it ideal for a new breed of imaging technologies, including user interface devices that can respond to gestures (touch not required).
“To our knowledge, we are the first to present an image sensor that is fully transparent – no integrated microstructures, such as circuits – and is flexible and scalable at the same time,” says team leader Oliver Bimber. The sensor is based on a polymer film known as a luminescent concentrator (LC). It is suffused with tiny fluorescent particles that absorb a very specific wavelength (blue light for example) and then reemit it at a longer wavelength (green light for example). Some of the reemitted fluorescent light is scattered out of the imager, but a portion of it travels throughout the interior of the film to the outer edges, where arrays of optical sensors (similar to 1-D pinhole cameras) capture the light. A computer then combines the signals to create a gray-scale image. “With fluorescence, a portion of the light that is reemitted actually stays inside the film,” says Bimber. “This is the basic principle of our sensor.” For the luminescent concentrator to work as an imager, Bimber and his colleagues had to determine precisely where light was falling across the entire surface of the film. This was the major technical challenge because the polymer sheet cannot be divided into individual pixels like the CCD camera inside a smartphone. Instead, fluorescent light from all points across its surface travels to all the edge sensors. The solution came from the phenomenon of light attenuation, or dimming, as it travels through the polymer. The longer it travels, the dimmer it becomes. So by measuring the relative brightness of light reaching the sensor array, it was possible to calculate where the light entered the film. The main application the researchers envision for this new technology is in touch-free, transparent user interfaces that could seamlessly overlay a television or other display technology. This would give computer operators or video-game players full gesture control without the need for cameras or other external motion-tracking devices.
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wow. intercontinental flying in just 1.5 hrs. By 2050 I would be about to die. And the acceleration might mean we would age faster.