Microsoft vient d’annoncer la date de sortie précise de la version Windows 8 de sa Surface Pro.
Avec la Surface RT, Microsoft nous proposait une première tablette 100% maison, mais loin d’être exempte de défauts. Des tares principalement dues à son système d’exploitation, Windows RT, un OS mobile à la conception assez discutable. Du coup, l’arrivée d’une version Pro de la tablette, équipée de Windows 8, pourrait donner un nouvel intérêt à l’appareil.
Initialement attendue pour le mois de janvier, la Surface Pro arrivera finalement le 9 février prochain, aux États-Unis et au Canada dans un premier temps. Si aucune date n’a été précisée pour l’Europe, on peut décemment espérer une mise en vente dans les semaines suivantes. La Surface Pro pourra être acquise sur la boutique en ligne de Microsoft (microsoftstore.com), dans les MS Store « physiques » et quelques enseignes de grande distribution (Staples, Best Buy). Elle sera vendue à partir de 899$, en version 64 ou 128 Go.
Pour rappel, la Surface Pro est équipée d’un processeur Intel Core i5 et son écran de 10,6 pouces affiche une définition de 1920 x 1080 pixels. Le format reste le même que celui de la version RT, à ceci près qu’elle fait 13.46 mm d’épaisseur, contre 9.39 mm, et pèse 903 grammes. Plus proche de l’ultrabook que de la tablette, elle serait, d’après les premiers retours de confrères américains, dotée d’une autonomie de 5 heures et propose une qualité d’affichage excellente. Il nous tarde en tout cas de mettre la main dessus.
June 26, 2013 — Energy conservation in a small number of households could go a long way to reducing greenhouse gas emissions, scientists are reporting.
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Their study, which measured differences in energy demands at the household level, appears in the ACS journal Environmental Science & Technology.
Dominik Saner and colleagues point out that the energy people use to power their homes and to satisfy their mobility needs accounts for more than 70 percent of emissions of carbon dioxide, the main greenhouse gas involved in global climate change. To cope with that problem, policymakers and environmentalists have focused largely on the supply side, for instance, electric power plants, heating systems and cars that release carbon dioxide into the atmosphere. Saner and his team decided to take a close look at the other end of the equation -- how energy consumption for housing and land-based mobility at the household level impacts greenhouse gas emissions.
Their study of more than 3,000 households in a Swiss town found that only 21 percent of the households accounted for almost 50 percent of greenhouse gas emissions. The biggest factors contributing to a few families having a disproportionately large environmental footprint were large living spaces (which use energy for heating, lighting and cooling) and long commutes in private vehicles. "If their emissions could be halved, the total emissions of the community would be reduced by 25 percent," the scientists concluded.
The authors acknowledge funding from the Competence Center for Energy & Mobility and Swisselectric Research.
La société américaine Media Development Investment Fund (MDIF), basée à New York, s'est lancée dans un projet fou : donner accès à Internet depuis l'espace. C'est en partant du constat que seuls 60% de la population mondiale avait accès à Internet que la firme a eu l'idée d'Outernet.
Pour réaliser ce projet, MDIF envisage déjà de lancer des centaines de satellites low cost miniatures qu'ils ont appelé "CubeSats". Miniatures oui, car ils ne font que 1,33 kg et 10 cm3. Ces satellites, en orbite autour de notre planète, permettraient de matérialiser l'Outernet et nous donneraient une connexion Wifi. Une connexion Wifi mondiale ET gratuite ! L'équipe chargée d'Outernet met tout en œuvre pour que le projet se concrétise vraiment à partir de juin 2015.
Cette technologie existe déjà et ne date pas d'hier puisque ces CubeSats ont été développés en 1999 par deux universités américaines, Stanford et Cal Poly. Ils sont par ailleurs toujours utilisés et aident à certaines missions scientifiques. MDIF souhaite utiliser les installations et les équipements de la station spatiale internationale de la Nasa en septembre 2014 et utilisera aussi la technologie UDP, User Datagram Protocol qui permettra le partage des données. Étant une organisation à but non lucratif, la firme espère réussir à lever des dizaines de millions de dollars pour finaliser le projet Outernet. S'ils réussissent ces paris, Outernet devrait bel et bien voir le jour.
La gratuité d'Outernet et son impact mondial permettra également de déjouer la censure dont certains pays sont victimes. Mieux encore, Outernet jouera un rôle extrêmement important en cas de catastrophes naturelles grâce à son système de notification global.
Attendu avec impatience par les fans de Marvel, le prochain opus de Captain America, nommé le Soldat de l'hiver, doit sortir dans les salles le mercredi 26 mars. Ce deuxième opus prends place peu de temps après les évènements de The Avengers (deux ans pour être exact).
Alors que le valeureux puceau au bouclier (incarné par Chris Evans) essaie de s'adapter au monde moderne après la défaite de Loki, les intrigues du SHIELD le rattrapent. Et il devra faire face à un ancien ami : Bucky, alias le Soldat de l'hiver. Heureusement, la Veuve Noire (aka Black Widow), incarnée par Scarlett Johansson, sera là pour épauler le justicier au drapeau américain.
Un Marathon Marvelien au Grand Rex
Avec une pensée pour les fans impatients, le Grand Rex et Marvel ont organisé pour le dimanche 23 mars un marathon des films liés à Captain America, qui se terminera par une avant-première de Captain America, Le Soldat de l'hiver.
La journée commencera à 13h30 avec Captain America, First Avenger, suivi de The Avengers à 16h00 et de l'avant-première à 19h15. On retrouvera donc les autres Avengers pour un Marvelthon qui devrait ravir les fans (à l'exception des puristes).
Il faudra compter 20 euros pour ce marathon, qui commencera donc à 13h30 pour ce finir aux alentours de 21h30. On ne sait pas pour vous, mais on attends avec impatience ce nouvel opus. Et promis, on ne spoilera pas (trop) le film après l'avoir vu.
En attendant l'avant-première (une situation légèrement cocasse), vous pouvez toujours vous arrachez les cheveux de frustration, ou regardez la dernière bande-annonce du film en VF ou VOSTFR (et baver) :
June 3, 2013 — Laser researchers in Munich are challenging a basic assumption of engineering: "You can't have it all." They have shown that for certain kinds of laser applications in biomedical imaging, material processing, and communications, a new approach could deliver the desired capabilities with no problematic tradeoffs: in compact, inexpensive, efficient and long-lived devices that produce ultrashort, high-energy light pulses.
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This research is a close collaboration between members of the Electrical Engineering and Information Technology Department at the Technische Universitaet Muenchen (TUM) and the Physics Department of LMU Munich.
Their latest paper, published in Nature Communications, describes experiments showing that cheap, robust semiconductor lasers can produce high-energy light pulses as short as 60 picoseconds (trillionths of a second) without the drawbacks of previous approaches in terms of power consumption and device size. At the same time it presents theoretical results predicting that this technique will break the next barrier for such lasers: subpicosecond pulses.
"Our models and simulations actually let us identify changes in the experimental setup that could yield a further thousand-fold improvement in performance," says Dr. Christian Jirauschek of TUM, "potentially producing pulses shorter than 30 femtoseconds."
Reshaping continuous wave output to short intense pulses
The Munich researchers' approach employs a relatively new kind of laser in a novel configuration. Dr. Robert Huber, leader of the LMU group, is co-inventor of this device, the Fourier domain mode-locked (FDML) laser. Rather than emitting light centered on one highly specific "color," the FDML laser rapidly and repeatedly sweeps through a range of wavelengths. The idea behind the experiment now is to reshape the continuous wave output from the FDML laser to short intense pulses.
"The advantage of this experimental configuration," Huber explains, "comes from storing the entire energy of each FDML laser sweep directly as a light field -- spread out like colors of an infrared rainbow -- in a kilometer-long optical fiber inside the laser resonator." This is more efficient than storing the energy in the semiconductor structure of the laser source. The different wavelength components travel at different speeds and enter a second optical fiber, outside the laser, at different times. This second fiber is laid out so that the different speeds exactly compensate for the different entry times: All colors exit the second fiber at the same time, forming a short laser pulse. This is the key to preserving high output energy even while shortening the pulse time -- without increasing power consumption or requiring the use of a larger device.
This research was supported by the Emmy Noether program of the German Research Foundation (DFG) -- HU 1006/2-1, JI 115/1-1; by the DFG project JI 115/2-1; and by the European Union through FUN OCT (FP7 HEALTH, contract number 201880) and FDML-Raman (ERC contract 259158).
Mar. 27, 2013 — Electronic computing speeds are brushing up against limits imposed by the laws of physics. Photonic computing, where photons replace comparatively slow electrons in representing information, could surpass those limitations, but the components of such computers require semiconductors that can emit light.
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Now, research from the University of Pennsylvania has enabled "bulk" silicon to emit broad-spectrum, visible light for the first time, opening the possibility of using the element in devices that have both electronic and photonic components.
The research was conducted by associate professor Ritesh Agarwal, postdoctoral fellow Chang-Hee Cho and graduate students Carlos O. Aspetti and Joohee Park, all of the Department of Materials Science and Engineering in Penn's School of Engineering and Applied Science.
Their work was published in Nature Photonics.
Certain semiconductors, when imparted with energy, in turn emit light; they directly produce photons, instead of producing heat. This phenomenon is commonplace and used in light-emitting diodes, or LEDs, which are ubiquitous in traffic signals, new types of light bulbs, computer displays and other electronic and optoelectronic devices. Getting the desired photonic properties often means finding the right semiconducting material. Agarwal's group produced the first ever all-optical switch out of cadmium sulfide nanowires, for example.
Semiconducting materials -- especially silicon -- form the backbone of modern electronics and computing, but, unfortunately, silicon is an especially poor emitter of light. It belongs to a group of semiconducting materials, which turns added energy into heat. This makes integrating electronic and photonic circuits a challenge; materials with desirable photonic properties, such as cadmium sulfide, tend to have poor electrical properties and vice versa and are not compatible with silicon-based electronic devices.
"The problem is that electronic devices are made of silicon and photonic devices are typically not," Agarwal said. "Silicon doesn't emit light and the materials that do aren't necessarily the best materials for making electronic devices."
With silicon entrenched as the material of choice for the electronics industry, augmenting its optical properties so it could be integrated into photonic circuitry would make consumer-level applications of the technology more feasible.
"People have tried to solve this problem by doping silicon with other materials, but the light emission is then in the very long wavelength range, so it's not visible and not very efficient and can degrade its electronic properties," Agarwal said. "Another approach is to make silicon devices that are very small, five nanometers in diameter or less. At that size you have quantum confinement effects, which allows the device to emit light, but making electrical connections at that scale isn't currently feasible, and the electrical conductivity would be very low."
To get elemental, "bulk" silicon to emit light, Agarwal's team drew upon previous research they had conducted on plasmonic cavities. In that earlier work, the researchers wrapped a cadmium sulfide nanowire first in a layer of silicon dioxide, essentially glass, and then in a layer of silver. The silver coating supports what are known as surface plasmons, waves that are a combination of oscillating metal electrons and of light. These surface plasmons are highly confined to the surface where the silicon dioxide and silver layers meet. For certain nanowire sizes, the silver coating creates pockets of resonance and hence highly confined electromagnetic fields -- in other words, light -- within the nanostructure.
Normally, after excitation the semiconductor must first "cool down," releasing energy as heat, before "jumping" back to the ground state and finally releasing the remaining energy as light. The Penn team's semiconductor nanowires coupled with plasmonic nanocavities, however, can jump directly from a high-energy excited state to the ground state, all but eliminating the heat-releasing cool-down period. This ultra-fast emission time opens the possibility of producing light from semiconductors such as silicon that might otherwise only produce heat.
"If we can make the carriers recombine immediately," Agarwal said, "then we can produce light in silicon."
In their latest work, the group wrapped pure silicon nanowires in a similar fashion, first with a coating of glass and then one of silver. In this case, however, the silver did not wrap completely around the wire as the researchers first mounted the glass-coated silicon on a sperate pane of glass. Tucking under the curve of the wire but unable to go between it and the glass substrate, the silver coating took on the shape of the greek letter omega -- Ω -- while still acting as a plasmonic cavity.
Critically, the transparent bottom of the omega allowed the researchers to impart energy to the semiconductor with a laser and then examine the light silicon emitted.
Even though the silicon nanowire is excited at a single energy level, which corresponds to the wavelength of the blue laser, it produces white light that spans the visible spectrum. This translates into a broad bandwidth for possible operation in a photonic or optoelectronic device. In the future, it should also be possible to excite these silicon nanowires electrically.
"If you can make the silicon emit light itself, you don't have to have an external light source on the chip," Agarwal said. "We could excite the silicon electrically and get the same effect, and we can make it work with wires from 20 to 100 nanometers in diameter, so it's very compatible in terms of length scale with current electronics."
The research was supported by the U.S. Army Research Office and the National Institutes of Health.
Nov. 25, 2013 — Kansas State University researchers are improving astronauts' outerwear for outer space.
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The collaborative team -- which includes electrical and computer engineering professors and more than a dozen students -- envisions a future spacesuit that could monitor astronauts' health and use body heat to power electronics. By working with a model spacesuit, the engineers are exploring how wearable medical sensors can be used in future space missions to keep astronauts healthy.
The project is supported by a three-year, $750,000 NASA grant and involves the College of Engineering's electrical and computer engineering department, the Electronic Design Laboratory and the College of Human Ecology, including the kinesiology department and the apparel, textiles and interior design department.
William Kuhn, professor of electrical and computer engineering, and Steven Warren, associate professor of electrical and computer engineering, are two key faculty members working on the engineering portion.
"This project supports a number of undergraduate and graduate students in doing systems-level engineering research and making them the technologists of the future," Kuhn said.
The project involves five parts, with several students involved in each part:
* Developing and testing biosensors that can monitor astronauts' vital data, such as breathing rate or muscle activity.
* Creating a specialized wireless network so that spacesuit biosensors can communicate with each other and with a space station.
* Using energy harvesting technology to power radios and biosensors while an astronaut is in a spacesuit.
* Building hardware prototypes for biosensors and energy harvesting electronics.
* Producing spinoff technologies, such as new radio technologies and devices that apply to home care.
"This project is a good example of how when you do something in space, everything needs to be rethought -- human elements and nonhuman elements of the system," Warren said. "We have a lot to learn about human physiology and what happens to a person as they physically change in a reduced-gravity environment."
The engineers are using 3D electromagnetic field simulators and a spacesuit model. Because real spacesuits cost $13 million, Erin Monfort-Nelson, master's student in apparel, textiles and interior design, Iola, built a replica of the spacesuit used in the space shuttle program. The suit replica is made of multiple layers of material, including metalized fabrics to model the layers in real suits that protect astronauts and keep them warm.
Batteries are too dangerous to place in a spacesuit's oxygen-rich environment, so the team is developing new energy harvesting methods to gather energy. These methods use the temperature difference between body heat and the spacesuit's cooling garment to power radios and other electronics inside the spacesuit.
"This is a systems-level project where we bring together integrated circuit design, software design, biomedical sensors and the biology of people," Kuhn said.
Added to the communication and power challenges in space is that astronauts' bodies also change in space. Muscle mass and bone density decrease and an astronaut's vision can change. Warren is working with Thomas Barstow, professor of kinesiology, and a team of students to develop sensors that astronauts can wear to measure their health and predict fatigue onset. Studies have involved simulated lunar tasks -- such as climbing ladders or collecting rock samples -- while wearing both commercial sensors and devices developed by the Kansas State University team.
Some of these wearable body area network sensors include:
* Electromyographic sensors to monitor muscle activity.
* Accelerometers to measure movement.
* Pulse oximetry sensors worn on the forehead, wrist or finger to measure blood oxygen saturation and heart rate.
* Chest-worn respiration belts to measure breathing rate.
The engineers also are developing ways for these sensors to communicate with each other in the suit and to a spacesuit hub that transmits the information back to the space station.
"This project is a fantastic community and team-building effort," Warren said. "It offers a good venue to establish a local community of researchers that have a fruitful and frequent dialogue to accomplish the same goal. We can move new ideas into the classroom and teach them to students."
Feb. 17, 2013 — University at Buffalo engineers have created a more efficient way to catch rainbows, an advancement in photonics that could lead to technological breakthroughs in solar energy, stealth technology and other areas of research.
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Qiaoqiang Gan, PhD, an assistant professor of electrical engineering at UB, and a team of graduate students described their work in a paper called "Rainbow Trapping in Hyperbolic Metamaterial Waveguide," published Feb. 13 in the online journal Scientific Reports.
They developed a "hyperbolic metamaterial waveguide," which is essentially an advanced microchip made of alternate ultra-thin films of metal and semiconductors and/or insulators. The waveguide halts and ultimately absorbs each frequency of light, at slightly different places in a vertical direction, to catch a "rainbow" of wavelengths.
Gan is a researcher within UB's new Center of Excellence in Materials Informatics.
"Electromagnetic absorbers have been studied for many years, especially for military radar systems," Gan said. "Right now, researchers are developing compact light absorbers based on optically thick semiconductors or carbon nanotubes. However, it is still challenging to realize the perfect absorber in ultra-thin films with tunable absorption band.
"We are developing ultra-thin films that will slow the light and therefore allow much more efficient absorption, which will address the long existing challenge."
Light is made of photons that, because they move extremely fast (i.e., at the speed of light), are difficult to tame. In their initial attempts to slow light, researchers relied upon cryogenic gases. But because cryogenic gases are very cold -- roughly 240 degrees below zero Fahrenheit -- they are difficult to work with outside a laboratory.
Before joining UB, Gan helped pioneer a way to slow light without cryogenic gases. He and other researchers at Lehigh University made nano-scale-sized grooves in metallic surfaces at different depths, a process that altered the optical properties of the metal. While the grooves worked, they had limitations. For example, the energy of the incident light cannot be transferred onto the metal surface efficiently, which hampered its use for practical applications, Gan said.
The hyperbolic metamaterial waveguide solves that problem because it is a large area of patterned film that can collect the incident light efficiently. It is referred to as an artificial medium with subwavelength features whose frequency surface is hyperboloid, which allows it to capture a wide range of wavelengths in different frequencies including visible, near-infrared, mid-infrared, terahertz and microwaves.
It could lead to advancements in an array of fields.
For example, in electronics there is a phenomenon known as crosstalk, in which a signal transmitted on one circuit or channel creates an undesired effect in another circuit or channel. The on-chip absorber could potentially prevent this.
The on-chip absorber may also be applied to solar panels and other energy-harvesting devices. It could be especially useful in mid-infrared spectral regions as thermal absorber for devices that recycle heat after sundown, Gan said.
Technology such as the Stealth bomber involves materials that make planes, ships and other devices invisible to radar, infrared, sonar and other detection methods. Because the on-chip absorber has the potential to absorb different wavelengths at a multitude of frequencies, it could be useful as a stealth coating material.
Additional authors of the paper include Haifeng Hu, Dengxin Ji, Xie Zeng and Kai Liu, all PhD candidates in UB's Department of Electrical Engineering. The work was sponsored by the National Science Foundation and UB's electrical engineering department.
Mar. 6, 2014 — Have you ever wondered why your laptop or smartphone feels warm when you're using it? That heat is a byproduct of the microprocessors in your device using electric current to power computer processing functions -- and it is actually wasted energy.
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Now, a team led by researchers from the UCLA Henry Samueli School of Engineering and Applied Science has made major improvements in computer processing using an emerging class of magnetic materials called "multiferroics," and these advances could make future devices far more energy-efficient than current technologies.
With today's device microprocessors, electric current passes through transistors, which are essentially very small electronic switches. Because current involves the movement of electrons, this process produces heat -- which makes devices warm to the touch. These switches can also "leak" electrons, making it difficult to completely turn them off. And as chips continue to get smaller, with more circuits packed into smaller spaces, the amount of wasted heat grows.
The UCLA Engineering team used multiferroic magnetic materials to reduce the amount of power consumed by "logic devices," a type of circuit on a computer chip dedicated to performing functions such as calculations. A multiferroic can be switched on or off by applying alternating voltage -- the difference in electrical potential. It then carries power through the material in a cascading wave through the spins of electrons, a process referred to as a spin wave bus.
A spin wave can be thought of as similar to an ocean wave, which keeps water molecules in essentially the same place while the energy is carried through the water, as opposed to an electric current, which can be envisioned as water flowing through a pipe, said principal investigator Kang L. Wang, UCLA's Raytheon Professor of Electrical Engineering and director of the Western Institute of Nanoelectronics (WIN).
"Spin waves open an opportunity to realize fundamentally new ways of computing while solving some of the key challenges faced by scaling of conventional semiconductor technology, potentially creating a new paradigm of spin-based electronics," Wang said.
The UCLA researchers were able to demonstrate that using this multiferroic material to generate spin waves could reduce wasted heat and therefore increase power efficiency for processing by up to 1,000 times. Their research is published in the journal Applied Physics Letters.
"Electrical control of magnetism without involving charge currents is a fast-growing area of interest in magnetics research," said co-author Pedram Khalili, a UCLA assistant adjunct professor of electrical engineering. "It can have major implications for future information processing and data-storage devices, and our recent results are exciting in that context."
The researchers previously applied this technology in a similar way to computer memory.
Sergiy Cherepov, a former UCLA postdoctoral scholar, was the lead author on the research. Cherepov, Khalili and Wang are members of the National Science Foundation-funded Center for Translational Applications of Nanoscale Multiferroic Systems (TANMS), which focuses on multiferroic device applications.
The research was funded by the Defense Advanced Research Projects Agency's Non-Volatile Logic program and the by the Nanoelectronics Research Initiative through the WIN.
Other authors included Juan G. Alzate, Kin Wong , Mark Lewis, Pramey Upadhyaya, Jayshankar Nath and Mingqiang Bao of UCLA's electrical engineering department; Alexandre Bur, Tao Wu and TANMS director Gregory Carman of UCLA's mechanical and aerospace engineering department; and Alexander Khitun, adjunct professor of electrical engineering at UC Riverside's Bourns College of Engineering.
Energy conservation is the practice of reducing the use of energy in order to increase national security, personal security, save money, be more comfortable and/or help clean the environment..
Alors que le nombre de testeurs des Google Glass a augmenté récemment, les avis à propos des nouvelles lunettes intelligentes de Google s'opposent de plus en plus. En témoigne aujourd'hui, l'agression d'une femme à San Fransisco pour l'unique motif qu'elle portait les fameuses lunettes dans un bar.
Depuis quelques temps déjà, les critiques envers les Google Glass se font de plus en plus nombreuses, et particulièrement contre le fait qu'elles offrent la possibilité de filmer n'importe quand, n'importe où. Alors que certains établissements publics les ont déjà interdites dans leurs locaux, notamment des bars et restaurants, on se demande s'ils ne devraient pas tous le faire pour éviter les débordements. En effet, la Glass Explorer Sarah Slocum s'est faite agresser le week-end dernier à la sortie d'un bar par des Google Glass haters. D'après le rapport de police, il semblerait que l'attaque ait eu lieu après que la testeuse ait expliqué au directeur de l'établissement le fonctionnement et les possibilités des lunettes, entrainant le mécontentement de certains clients du bar. Sarah a posté un message sur son profil Facebook directement après :
"OMG so you'll never believe this but... I got verbally and physically asaulted and robbed last night in the city, had things thrown at me because of some wanker Google Glass haters, then some *bleeeeeeeeeep* tore them off my face and ran out with them then and when I ran out after him his *bleeeeeeep* friends stole my purse, cellphone walet and everything."
"Oh mon dieu, vous n’allez jamais croire ça... J’ai été verbalement et physiquement agressée et volée la nuit dernière en ville. Tout ça à cause de quelques Google Glass haters. Ensuite un d’eux me les a arrachées et s’est enfui avec. J’ai tenté de le poursuivre mais son ami en a profité pour voler mon sac, mon téléphone, mon portefeuille et tout le reste."
Les réactions quant à ce poste sont néanmoins opposées et les sources qui témoignent de l'incident divergent en partie du rapport de police. En effet, il semblerait que certaines personnes dans le bar lui aient demandé à plusieurs reprises de retirer les lunettes, ce à quoi elle aurait répondu négativement. Un des amis de la jeune femme aurait ensuite répondu aux mécontents par la force. Les divergences de témoignages montrent bien la tension qui règne entre les partisans et les opposants de ce type de technologie et prouvent qu'il s'agit d'un sujet sensible.
En réponse aux problèmes engendrés par les lunettes connectées, Google a rédigé une Charte de bonne conduite pour les porteurs de Google Glass, mais il semblerait que la démarche soit trop faible pour rassurer les opposants aux lunettes intelligentes du géant.
Sep. 4, 2013 — Researchers in the College of Engineering at Oregon State University have made a significant advance in the function of metal-insulator-metal, or MIM diodes, a technology premised on the assumption that the speed of electrons moving through silicon is simply too slow.
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For the extraordinary speed envisioned in some future electronics applications, these innovative diodes solve problems that would not be possible with silicon-based materials as a limiting factor.
The new diodes consist of a "sandwich" of two metals, with two insulators in between, to form "MIIM" devices. This allows an electron not so much to move through materials as to tunnel through insulators and appear almost instantaneously on the other side. It's a fundamentally different approach to electronics.
The newest findings, published in Applied Physics Letters, have shown that the addition of a second insulator can enable "step tunneling," a situation in which an electron may tunnel through only one of the insulators instead of both. This in turn allows precise control of diode asymmetry, non-linearity, and rectification at lower voltages.
"This approach enables us to enhance device operation by creating an additional asymmetry in the tunnel barrier," said John F. Conley, Jr., a professor in the OSU School of Electrical Engineering and Computer Science. "It gives us another way to engineer quantum mechanical tunneling and moves us closer to the real applications that should be possible with this technology."
OSU scientists and engineers, who only three years ago announced the creation of the first successful, high-performance MIM diode, are international leaders in this developing field. Conventional electronics based on silicon materials are fast and inexpensive, but are reaching the top speeds possible using those materials. Alternatives are being sought.
More sophisticated microelectronic products could be possible with the MIIM diodes -- not only improved liquid crystal displays, cell phones and TVs, but such things as extremely high-speed computers that don't depend on transistors, or "energy harvesting" of infrared solar energy, a way to produce energy from Earth as it cools during the night.
MIIM diodes could be produced on a huge scale at low cost, from inexpensive and environmentally benign materials. New companies, industries and high-tech jobs may ultimately emerge from advances in this field, OSU researchers say.
The work by Conley and OSU doctoral student Nasir Alimardani has been supported by the National Science Foundation, the U.S. Army Research Laboratory and the Oregon Nanoscience and Microtechnologies Institute.
Jan. 27, 2014 — A new type of electrical generator uses bacterial spores to harness the untapped power of evaporating water, according to research conducted at the Wyss Institute of Biologically Inspired Engineering at Harvard University. Its developers foresee electrical generators driven by changes in humidity from sun-warmed ponds and harbors.
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The prototype generators work by harnessing the movement of a sheet of rubber coated on one side with spores. The sheet bends when it dries out, much as a pine cone opens as it dries or a freshly fallen leaf curls, and then straightens when humidity rises. Such bending back and forth means that spore-coated sheets or tiny planks can act as actuators that drive movement, and that movement can be harvested to generate electricity.
"If this technology is developed fully, it has a very promising endgame," said Ozgur Sahin, Ph.D., who led the study, first at Harvard's Rowland Institute, later at the Wyss Institute, and most recently at Columbia University, where he's now an associate professor of biological sciences and physics. Sahin collaborated with Wyss Institute Core Faculty member L. Mahadevan, Ph.D., who is also the Lola England de Valpine professor of applied mathematics, organismic and evolutionary biology, and physics at the School of Engineering and Applied Sciences at Harvard University, and Adam Driks,Ph.D., a professor of microbiology and immunology at Loyola University Chicago Stritch School of Medicine. The researchers reported their work yesterday in Nature Nanotechnology.
Water evaporation is the largest power source in nature, Sahin said. "Sunlight hits the ocean, heats it up, and energy has to leave the ocean through evaporation," he explained. "If you think about all the ice on top of Mt. Everest -- who took this huge amount of material up there? There's energy in evaporation, but it's so subtle we don't see it."
But until now no one has tapped that energy to generate electricity.
As Sahin pursued the idea of a new humidity-driven generator, he realized that Mahadevan had been investigating similar problems from a physical perspective. Specifically, he had characterized how moisture deforms materials, including biological materials such as pinecones, leaves and flowers, as well as human-made materials such as a sheet of tissue paper lying in a dish of water.
Sahin collaborated with Mahadevan and Driks on one of those studies. A soil bacterium called Bacillus subtilis wrinkles as it dries out like a grape becoming a raisin, forming a tough, dormant spore. The results, which they reported in 2012 in the Journal of the Royal Society Interface, explained why.
Unlike raisins, which cannot re-form into grapes, spores can take on water and almost immediately restore themselves to their original shape. Sahin realized that since they shrink reversibly, they had to be storing energy. In fact, spores would be particularly good at storing energy because they are rigid, yet still expand and contract a great deal, the researchers predicted.
"Since changing moisture levels deform these spores, it followed that devices containing these materials should be able to move in response to changing humidity levels," Mahadevan said. "Now Ozgur has shown very nicely how this could be used practically."
When Sahin first set out to measure the energy of spores, he was taken by surprise.
He put a solution thick with spores on a tiny, flexible silicon plank, expecting to measure the humidity-driven force in a customized atomic force microscope. But before he could insert the plank, he saw it curving and straightening with his naked eye. His inhaling and exhaling had changed the humidity subtly, and the spores had responded.
"I realized then that this was extremely powerful," Sahin said.
In fact, simply increasing the humidity from that of a dry, sunny day to a humid, misty one enabled the flexible, spore-coated plank to generate 1000 times as much force as human muscle, and at least 10 times as much as other materials engineers currently use to build actuators, Sahin discovered. In fact, moistening a pound of dry spores would generate enough force to lift a car one meter off the ground.
To build such an actuator, Sahin tested how well spore-coated materials such as silicon, rubber, plastic, and adhesive tape stored energy, settling on rubber as the most promising material.
Then he built a simple humidity-driven generator out of Legos™, a miniature fan, a magnet and a spore-coated cantilever. As the cantilever flips back and forth in response to moisture, it drives a rotating magnet that produces electricity.
Sahin's prototype captures just a small percentage of the energy released by evaporation, but it could be improved by genetically engineering the spores to be stiffer and more elastic. Indeed, in early experiments, spores of a mutant strain provided by Driks stored twice as much energy as normal strains.
"Solar and wind energy fluctuate dramatically when the sun doesn't shine or the wind doesn't blow, and we have no good way of storing enough of it to supply the grid for long," said Wyss Institute Founding Director Don Ingber, M.D., Ph.D. "If changes in humidity could be harnessed to generate electricity night and day using a scaled up version of this new generator, it could provide the world with a desperately needed new source of renewable energy."
The work was funded by the U.S. Department of Energy, the Rowland Junior Fellows Program, and the Wyss Institute for Biologically Inspired Engineering at Harvard University. In addition to Sahin, Driks and Mahadevan, the authors included Xi Chen, a postdoctoral research associate at Columbia University.
Dec. 8, 2013 — The energy needed to change the magnetic orientation of a single atom -- which determines its magnetic stability and therefore its usefulness in a variety of future device applications -- can be modified by varying the atom's electrical coupling to nearby metals.
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This striking result was published today in the journal Nature Nanotechnology by an international group of scientists working at the London Centre for Nanotechnology (LCN) at UCL (UK), the Iberian Nanotechnology Laboratory (Portugal), the University of Zaragoza (Spain), and the Max Planck Institute of Microstructure Physics (Germany).
Anyone playing with two magnets can experience how they repel or attract each other depending on the relative orientation of their magnetic poles. The fact that in a given magnet these poles lie along a specific direction rather than being randomly oriented is known as magnetic anisotropy, and this property is exploited in a variety of applications ranging from compass needles to hard drives.
"For 'large' pieces of magnetic material," emphasized Dr Joaquín Fernández-Rossier from the INL, "magnetic anisotropy is determined primarily by the shape of a magnet. The atoms that form the magnetic material are also magnetic themselves, and therefore have their own magnetic anisotropy. However, atoms are so small that it is hardly possible to ascribe a shape to them, and the magnetic anisotropy of an atom is typically controlled by the position and charge of the neighbouring atoms."
Using a scanning tunnelling microscope, an instrument capable of observing and manipulating an individual atom on a surface, LCN researchers and their colleagues discovered a new mechanism that controls magnetic anisotropy at the atomic scale.
In their experiment, the research team observed dramatic variations in the magnetic anisotropy of individual cobalt atoms depending on their location on a copper surface capped with an atomically-thin insulating layer of copper nitride.
These variations were correlated with large changes in the intensity of another phenomenon -- the Kondo effect -- that arises from electrical coupling between a magnetic atom and a nearby metal. With the help of theoretical and computational modelling performed in Germany and Portugal, the researchers found that, in addition to the conventional structural mechanisms, the electronic interactions between the metal substrate and the magnetic atom can also play a major role in determining magnetic anisotropy.
"Electrical control of a property that formerly could only be tuned through structural changes will enable significant new possibilities when designing the smallest possible devices for information processing, data storage, and sensing," said LCN researcher Dr Cyrus Hirjibehedin.
In contrast to the more conventional mechanisms, this contribution to the magnetic anisotropy can be tuned electrically using the same process that drives many transistors, the field effect. These results are particularly timely because they support efforts to find material systems with large magnetic anisotropy that are free of rare earth elements, scarce commodities whose mining has large environmental impact.
June 11, 2013 — Imagine a number of different companies sharing a single fleet of electric vehicles... Fraunhofer IAO and eight project partners are busy working out just how to make this vision a reality. Funded by the German Federal Ministry of Economics and Technology, the Shared E-Fleet research project aims not only to work up suitable IT solutions, but also to design the smart energy management and profitable business models that are called for.
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While electric vehicles are becoming a more common sight in Germany, the government's target of having one million of them on the country's roads by the year 2020 still seems a long way off; it will take a definite jump in user acceptance to meet this target. Corporate fleets represent a promising market segment for electric vehicles, and they could act as a strong signal to the public at large that the tide is turning.
Right now in Germany, some 100,000 companies are using corporate fleets, with most fleets run by small and medium-sized companies. And it is for this kind of user in particular that fleet sharing is a viable alternative to the expense of buying and maintaining a fleet of their own.
As part of the Shared E-Fleet project, Fraunhofer IAO and its eight project partners are busy developing suitable concepts for how a single fleet of electric vehicles could be shared by many different companies. Key questions include how to make vehicle reservations user-friendly, billing straightforward, and vehicle charging ecologically sound and cost-effective. Shared E-Fleet will use real application scenarios to work up and test solutions in a variety of pilot schemes. Pilot users for these tests will include the Stuttgarter Engineering Park (STEP) and Münchner Technologiezentrum (MTZ) technology parks.
According to a recent survey, potential users view electromobility in a fundamentally positive light. What is more, the conditions for when it makes sense to use electric vehicles are effectively already being met: business journeys are generally no more than 100 kilometers, for example. What future users are skeptical about is the profitability of electric vehicles in a business context.
This highlights how important it is to establish profitable business models -- which is one of the topics Fraunhofer IAO is addressing as part of the Shared E-Fleet project. Another topic that will prove critical to the success of electric vehicle fleets is that of smart energy management. In tackling this issue, Fraunhofer IAO is exploring how to reconcile fleet vehicles' charging needs with their operating schedules. Once the conceptual design and implementation phase is completed, the Shared E-Fleet pilot scheme is set to get underway in early 2014.
The Shared E-Fleet consortium is made up of Carano Software Solutions GmbH (consortium leader), baimos technologies gmbh, Fraunhofer IAO, LMU Munich university, Marquardt GmbH, MGH-Münchner Gewerbehof- und Technologiezentrumsgesellschaft mbH, Siemens AG, STEP Stuttgarter Engineering Park GmbH, and TWT GmbH Science & Innovation.
For more information, visit: http://www.shared-e-fleet.de/
Aug. 6, 2013 — The Online Electric Vehicle (OLEV), developed by the Korea Advanced Institute of Science and Technology (KAIST), is an electric vehicle that can be charged while stationary or driving, thus removing the need to stop at a charging station. Likewise, an OLEV tram does not require pantographs to feed power from electric wires strung above the tram route.
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Following the development and operation of commercialized OLEV trams (at an amusement park in Seoul) and shuttle buses (at KAIST campus), respectively, the City of Gumi in South Korea, beginning on August 6th, is providing its citizens with OLEV public transportation services.
Two OLEV buses will run an inner city route between Gumi Train Station and In-dong district, for a total of 24 km roundtrip. The bus will receive 20 kHz and 100 kW (136 horsepower) electricity at an 85% maximum power transmission efficiency rate while maintaining a 17cm air gap between the underbody of the vehicle and the road surface.
OLEV is a groundbreaking technology that accelerates the development of purely electric vehicles as a viable option for future transportation systems, be they personal vehicles or public transit. This is accomplished by solving technological issues that limit the commercialization of electric vehicles such as price, weight, volume, driving distance, and lack of charging infrastructure.
OLEV receives power wirelessly through the application of the "Shaped Magnetic Field in Resonance (SMFIR)" technology. SMFIR is a new technology introduced by KAIST that enables electric vehicles to transfer electricity wirelessly from the road surface while moving. Power comes from the electrical cables buried under the surface of the road, creating magnetic fields. There is a receiving device installed on the underbody of the OLEV that converts these fields into electricity. The length of power strips installed under the road is generally 5%-15% of the entire road, requiring only a few sections of the road to be rebuilt with the embedded cables.
OLEV has a small battery (one-third of the size of the battery equipped with a regular electric car). The vehicle complies with the international electromagnetic fields (EMF) standards of 62.5 mG, within the margin of safety level necessary for human health. The road has a smart function as well, to distinguish OLEV buses from regular cars -- the segment technology is employed to control the power supply by switching on the power strip when OLEV buses pass along, but switching it off for other vehicles, thereby preventing EMF exposure and standby power consumption. As of today, the SMFIR technology supplies 60 kHz and 180 kW of power remotely to transport vehicles at a stable, constant rate.
Dong-Ho Cho, a professor of the electrical engineering and the director of the Center for Wireless Power Transfer Technology Business Development at KAIST, said: "It's quite remarkable that we succeeded with the OLEV project so that buses are offering public transportation services to passengers. This is certainly a turning point for OLEV to become more commercialized and widely accepted for mass transportation in our daily living."
After the successful operation of the two OLEV buses by the end of this year, Gumi City plans to provide ten more such buses by 2015.
Fantasme de l'écolière, films X avec de nombreuses scènes de viol, vente de petites culottes usagées ou de parfums très douteux pour poupées gonflables, il suffit de faire un tour dans un sex shop au Japon pour découvrir la perversion de certains de ses habitants. Mais qu'elle est l'origine réelle de cette perversion. S'agit-il d'une réaction vis à vis d'une interdiction ou de l'héritage d'un passé déluré ? C'est ce que nous allons tenter de comprendre à travers ce dossier au coeur des pratiques japonaises les plus perverses.
Le culte shintoïste
L'une des origines de la "perversion" de certains Japonais ou plus précisément de leurs moeurs sexuelles plus libérées que dans d'autres pays, se trouve très probablement dans la religion Shinto. Pratiquée par de très nombreux Japonais elle repose sur un principe de séparation du corps et de l'esprit, comme c'est le cas dans l'Islam, le Christianisme ou le Judaïsme. Toutefois, le Shinto se différencie des trois grandes religions par l'importance accordée au bonheur du corps qui est égale à celle dédiée à l'esprit. Le sexe est donc beaucoup moins tabou au Japon que dans d'autres pays. Faire l’amour est considéré comme un acte sacré, qui participe de l’acte divin.
L'image de la femme au Japon
Une autre raison de la perversion de certains japonais est à chercher dans l'image de la femme dans la société japonaise. Cette dernière prend plusieurs visages. La première est celle de la mère. Culturellement dévouée à son mari et à ses enfants. La mère japonaise occupe une place presque sacrée dans la famille japonaise. Et de nombreux fils rechercheront cette image maternelle lors de leur émancipation et durant la quête d'une femme. Une démarche qui peut conduire à un certain retour en arrière dans la manière d'aborder l'amour. Un retour en adolescence qui peut notamment expliquer l'intérêt très prononcé pour les étudiantes et notamment leur tenue d'école. On débarque très logiquement sur le phénomène kawaii et sa déclinaison vestimentaire. Littéralement, le mot kawaii signifie mignon et touche de nombreux domaines comme les animaux, la mode, les chansons...
Le kawaii intervient dans le mode de consommation de la sexualité par les japonais à travers les Maid Café. Décorés comme des chambres de petites filles, on vient ici pour se faire servir par des jeunes filles habillées en uniforme de domestique. Les clients, essentiellement des otaku (personne très casanière vouant une passion pour les mangas, animés...) s'alcoolisent et finissent parfois déguisés en train de se prendre en photo avec des serveuses qui les frappent avec des massues en plastique. On se croirait au jardin d'enfants, mais avec des adultes. Si la frontière entre la prostitution ou la pédophilie n'est pas loin, elle ne semble pas être franchie. En effets, les attouchements ne sont pas de la partie, mais la lubricité se lit dans les yeux des participants. Avec le temps, les Maid Café se sont largement diversifiés et on en trouve même où les jeunes filles se griment en vieillardes.
Le culte de la petite culotte
Le fétichisme est également partie intégrante de la sexualité au Japon. Et à ce petit jeu, la petite culotte figure en haut de l'échelle des objets les plus convoités. On aperçoit le bout de tissu dans la plupart des mangas, le super-héros Hentai Kamen tire même son pouvoir en se mettant une petite culotte sur le visage. Mais l'une des variantes les plus extrêmes est certainement le Burusera shop. Ce magasin d'un genre un peu spécial, vend presque exclusivement des petites culottes usagées et portées par des étudiantes. Trace de transpiration, d'urine, voire pire, on en trouve pour tous les goûts. Plus que la perversion, c'est ici le vice qui entre en jeu. Notez que les étudiantes vendent souvent très cher leur sous-vêtements sales pour financer leurs études. Les Burusera shop ont fait l'objet de nombreuses tentatives de fermeture, mais, aux dernières nouvelles, de tels magasins existeraient encore.
Les poupées gonflables connaissent également un très grand succès au Japon. Rien de très original ici. Toutefois, ces dernières s'accompagnent de tout un attirail d'accessoires. A ce propos, nous vous parlions il a quelques temps de la panoplie de parfums pour poupées gonflables. Parmi les odeurs disponibles : transpiration d'une jeune sportive, pied, anus de garçon, éjaculation féminine.
La frustration à l'origine de certaines perversions
Frustrés et conditionnés dès leur plus tendre enfance, certains Japonais en deviennent pervers. Ajoutez à cela un stress omniprésent au travail et des temps de repos très limités. Par ailleurs, si le sexe n'est pas tabou, la manifestation des émotions l'est beaucoup plus. Montrer ses sentiments est très compliqué et déclaré sa flamme à une femme prend plusieurs semaines et tout est orchestré par des tierces personnes. La recherche perpétuelle de l'exemplarité est également un phénomène qui accentue le "défoulement" dans la sphère privée. Et en effet, quand les Japonais se lâchent, ils le font sans retenue. On retrouve ce phénomène à la sortie des bureaux, quand les employés fréquentent les bars et en ressortent le plus souvent dans un état d'ébriété avancé. Il en est de même dans la sexualité, où la recherche du jusqu'au boutisme est parfois un moteur qui pousse à des pratiques très étranges.
"Les films pornographiques sont toujours floutés pour cacher les parties intimes des acteurs et actrices. Hallucinant !"
Notez que cette perversion dans la sexualité est surtout présente chez les hommes de plus de 50 ans qui ont passé toute leur vie à travailler et veulent rattraper le temps perdu de la manière la plus régulière et parfois la plus trash. Il faut également composer avec la vision très négative du divorce au Japon qui pousse certains couples à rester ensemble toute leur vie, se privant parfois de sexualité et allant chercher cette dernière ailleurs et d'une manière bien plus trash. Comble de l'ironie, un arrêté de 1956 interdit toujours la prostitution. Par ailleurs, les films pornographiques sont toujours floutés pour cacher les parties intimes des acteurs et actrices. Hallucinant !
Des pratiques extrêmes
Si vous avez déjà été choqué par certaines pratiques évoquées ci-dessus, passez votre chemin sur ce dernier chapitre qui va aller un cran plus loin dans le vice et la perversion. Commençons de manière assez soft avec l'eye ball licking ou oculolinctus. Oui, vous avez bien compris, il s'agit de se faire lécher le globe oculaire avec tous les risques d'infections oculaires que cette pratique comporte. Et on remercie les enfants japonais qui pratiquent ça durant les pauses à l'école. Continuons avec le bukkake. Si à l'origine, il s'agit d'un plat de nouilles, le terme à été repris par le monde pornographique pour désigner une éjaculation collective sur le visage et le corps d'un homme ou d'une femme. L'éjaculation se pratique également directement dans la rue chez les spécimens les plus dérangés qui se masturbent littéralement sur les passants. Une variante dans les transports en commun est également répandue, tout comme celle, beaucoup plus courante du tripotage dans les wagons bondés. Passons brièvement sur les films mettant en scène des viols, des pratiques SM extrêmes ou sur les adeptes de la scatophilie et du vomi. Trop basique ! Pour les amoureux des animaux, le Genki-Genki est une forme de zoophilie qui apparait dans certains films et séries photos. Petite particularité, on y croise des espèces très variées comme des poissons (surtout des anguilles qui s'immiscent dans des orifices), des poulpes, des crapauds, des larves d'insectes...
Photos de Daikichi Amano illustrant le Genki-Genki
Notez que certaines pratiques évoquées dans ce dossier le sont également dans beaucoup d'autres pays et qu'il n'est pas question de faire passer les Japonais pour des obsédés sexuels. Cependant, le Japon fait parfois figure d'exception dans sa manière d'accepter, voire même de banaliser certaines pratiques sexuelles. La notion de tabou étant beaucoup moins importante au Japon, des formes de sexualité sont plus facilement abordées. Par ailleurs, le Japon est parfois le pays d'origine de pratiques sexuelles qui en s'exportant véhicule l'image de la perversion japonaise.
June 4, 2013 — A new study finds that utilities aren't rewarded for adopting energy efficiency programs, and that reforms are needed to make energy efficiency as attractive as renewables.
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The article, just published in the current issue of Environmental Law, examines key differences between energy efficiency projects and renewable resources. Author Inara Scott, an assistant professor at Oregon State University, outlines ways to increase the amount of energy utilities save each year through efficiency programs.
"Right now, the system actually discourages utilities from building programs to increase efficiency," she said. "We need to start addressing efficiency as we do renewable energy -- by looking at it systemically and removing the barriers."
Scott spent a decade as a lawyer specializing in energy and regulatory law. Her research in the College of Business centers on the transformation of utility systems, clean energy, energy efficiency, and utility regulation.
Her study makes four key recommendations: redesigning rate structures, setting hard targets, streamlining cost-effective tests and addressing market barriers.
Cost-recovery systems for many investor-owned utilities in the United States are based on an old rate structure model -- the more energy that is produced, the higher return for shareholders. "You don't want to penalize utilities for selling less energy," Scott said.
Instead, she said, states can use ratemaking mechanisms to decouple the link between utility sales and revenues and establish performance incentives for the adoption of efficiency programs.
"Decoupling mechanisms may add complexity to utility rate structures, but they are essential to eliminating environmentally nonsensical ratemaking models that reward utilities for higher sales and penalize them for efficiency."
Setting hard targets is doable, she said. The state of Oregon has set a goal for 25 percent of its energy to be consumed through renewables by 2025. Scott said other states also could set aspirational goals for energy efficiency.
"If states are committed to reducing the strain on the electric grid, diversifying utility resource portfolios, reducing dependence on foreign markets, and reducing carbon emissions through the adoption of renewable resources, they should be just as willing to do so through the adoption of energy efficiency as they are through the purchase of renewable resources."
Streamlining cost-effectiveness tests will be difficult, Scott said, because a simple, accurate way to measure energy efficiency does not exist. "The difficulty is that you're trying to measure energy you didn't use. So really, you're measuring something that doesn't exist."
Many of the tests that do exist are so complicated that they may discourage utilities from adopting energy efficiency. Issues with cost-effectiveness testing will be difficult to fully remedy, Scott said, but these steps -- conducting assessments at a programmatic level, streamlining the precision of tests, and considering the development of national standards -- will move the bar forward.
Market barriers, Scott said, can be addressed through incentives. Some states, including Colorado and Michigan, have increased the size of incentives for consumers to take on energy efficiency programs (including, in some cases, reimbursing consumers 100 percent of their investment) and finding ways to make incentives more attractive to customers through advertising and education.
"There needs to be better marketing around efficiency," Scott said. "We need to make increasing energy efficiency as attractive as opting for 'green' or 'salmon-friendly' renewables."
Apr. 19, 2013 — A local power failure in Ohio ten years ago caused a series of cascading power failures that resulted in a massive blackout that affected 50 million people and caused billions of dollars in damage and lost revenue.
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Such blackouts could be prevented in the future, thanks to a new piece of equipment developed by engineering researchers at the University of Arkansas. The device regulates or limits the amount of excess current that moves through the power grid when a surge occurs.
"We didn't invent the fault current limiter," said Alan Mantooth, Distinguished Professor and executive director of the National Center for Reliable Electric Power Transmission, based at the university. "But we have developed the first one using a silicon-carbide semiconductor device and technology, which we have developed over the past five years. The significance of this material cannot be overestimated. It is much more durable and responds so much faster than materials currently used in systems on the U.S. power grid."
A fault current, also known as a surge, occurs when too much current flows through the electrical power grid in an uncontrolled manner. A fault current is typically caused by an accident or unintended event, such as lightning or contact between power lines and trees. These events cause short-circuits, which result in a rapid increase in the electricity drawn from power sources within the grid.
When these sources do not have extra power to give, cascading or rolling blackouts can occur. This is what happened in Ohio, much of the northeast United States and parts of Canada in 2003.
A fault current limiter can be thought of as a giant surge protector. When excess current travels through a power line, the limiter absorbs it and then sends only what is necessary farther down the line, Mantooth said. The system thus ensures uninterrupted service when the fault is intermittent. Most consumers would not even detect a problem. Furthermore, if the fault is more permanent and will require repair to power lines, Mantooth said, the device then opens much like a normal circuit breaker, which would thus prevent further damage due to excess current.
Proper coordination and device placement will prevent cascading outages, he said.
"This device really can mean the difference between 25,000 customers or 5 million customers being affected," Mantooth said.
The U of A researchers worked with silicon-carbide, a semiconducting material that is stronger and faster than conventional materials used in the power grid. High-speed switching devices within the limiter rapidly insert energy-absorbing impedance into the circuit or use advanced control techniques to limit the fault current, Mantooth said.
Silicon-carbide has other benefits as well. Its properties allow for extremely high voltage, and it is a good thermal conductor, which means that it can operate at high temperatures without requiring extra equipment to remove heat. Overall, use of the material will reduce the mass and volume of equipment needed on a power grid.
Mantooth envisions the device working in concert with circuit breakers on individual buildings, especially critical facilities such as hospitals. It could also serve neighborhoods, where one limiter could regulate current and thus preserve power for many houses. Depending on the size of the building or neighborhood, devices would vary in terms of amperage and voltage.
Mantooth said the U of A's system, and fault current limiters in general, are examples of devices that will make and serve a "smart" grid, meaning they will play an integral role in the U.S. Department of Energy's vision for a more efficient and more reliable power grid.
The National Center for Reliable Electric Power Transmission is funded as part of the federal government's focus on research and development on smart grid and renewable technologies. The center is one of only a few university-based research centers chosen by the Energy Department to investigate electronic systems to make the nation's power grid more reliable and efficient.
The Energy Department has funded the center since 2005 because of the university's research expertise in advanced power electronics and long-term investigation of silicon-carbide.
Mantooth is holder of the Twenty-First Century Chair in Mixed-Signal Integrated Circuit Design and Computer-Aided Design in the College of Engineering.
Sep. 10, 2013 — A device developed at The University of Alabama in Huntsville has become a valuable tool in researchers' quest to determine how lightning is spawned in clouds, to map strikes from beginning to end and to better predict severe weather.
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The Huntsville Alabama Marx Meter Array (HAMMA) sensor literally resides under a large inverted metal salad bowl to protect the electronics from rain. A modern electronic reinvention of a sensor first developed in the 1950s, it detects the radiated electric field in the atmosphere when lightning strikes.
"We take the lightning induced change in the electric field and it's converted to a voltage reading by our equipment and that's transmitted to our computer," said Dr. Phillip Bitzer, an assistant professor of atmospheric science, co-developer of the HAMMA device and the lead author of the study showing its usefulness.
Using the data from a network of HAMMA sensors, the computer generates maps showing the intensity and distribution of the lightning.
Very low frequency
Operating in the very low frequency (VLF) spectrum, HAMMA can detect both the intensity and duration of a bolt, called its energetics, and provide scientists with more information than previous mapping array instruments, which usually operate in the very high frequency (VHF) spectrum.
VHF equipment is better at detecting the smaller discharge processes from a lightning strike, while the VLF HAMMA device reads large discharges that are associated with more energetic processes, like the bright return stroke, Dr. Bitzer said. "The combination of VLF and VHF measurements may tell us a whole lot more about what is going on in the flash than either one by itself."
HAMMA may also help with one of the mysteries of nature -- exactly how a lightning bolt gets started in the clouds, an event scientists call initiation.
"We really don't know how initiation works," said Dr. Bitzer. "One of the big unanswered questions of lightning research is initiation, and that's one we are interested in. We're trying to get a handle on how lightning starts. How does all of this work?"
It's known that lightning is caused by buildup of positive and negative electrical charges inside a cloud. In the cloud, an embryonic version of hail called graupel collides with ice crystals. This collision usually leads to graupel acquiring a negative charge and ice a positive charge. These separate in a thunderstorm updraft to produce the electric field necessary to produce lightning. However, researchers have never measured an electric field sufficiently strong to itself initiate a lightning strike. Something else must happen to trigger the event, and there are two primary theories about that.
The first theory postulates that the electric field is locally enhanced by the hydrometeors in the cloud, thus enabling lightning to initiate. A competing theory suggests that cosmic rays bombarding Earth from outer space initiate lightning by introducing high-energy electrons that begin the cascade leading to a strike. HAMMA now gives researchers a front-row seat to the processes going on at initiation.
"What we're able to detect is the initiation of the lightning, which is typically about 30 milliseconds ahead of the lightning stroke," said Dr. Bitzer. This is the point in a lightning strike when the bolt sends down electrical "leaders" that eventually meet with ascending leaders from Earth to form the pathway the stroke then follows.
"One thing we've been able to show is that using VLF measurements in a network like HAMMA can give us a better idea of the location of different-scale processes that occur during initiation," Dr. Bitzer said. "In addition, you are able to estimate the strength of a flash."
Historic databases created from past storms can be valuable in predicting the behavior of future ones, Dr. Bitzer said, because there is a significant uptick in lightning strikes that precedes the main event as a storm arrives.
"If you include lightning data with currently used observations, we're better able to forecast severe weather," he said. "This system will show whether we are able to incorporate energetics to then increase lead time to predict a severe storm."
More tools ahead
UAH researchers are working on more tools to get to the core of the process that causes lightning to strike, including development of a Geostationary Lightning Mapper (GLM). The GLM will allow UAH scientists to view storms from space in a geostationary orbit ¬-a fixed position relative to Earth -- providing unprecedented ability to track lightning activity.
Similar measurements are currently provided by the Lightning Imaging Sensor (LIS); however, this instrument is on a satellite that is in low-earth orbit, which means it is unable to track changes in lightning activity over the lifetime of a storm. Another version of LIS built at the same time as the first is scheduled by NASA to be mounted on the International Space Station. UAH engineers are testing and calibrating it now.
In 2015, the GLM will fly on the Geostationary Operational Environmental Satellite R-Series (GOES-R) a joint effort between NASA and the National Oceanic and Atmospheric Administration (NOAA). Engineers at UAH are helping to build GLM and UAH scientists are working on how the GLM will gather information. Other UAH researchers are working on how to transition the gathered data to weather forecasters in a form that is most useful to them for predictions.
HAMMA will play a key role in validating GLM performance and further understanding of the data it provides. The measurements from space are well correlated to VLF measurements that HAMMA provides. "HAMMA is a great complement to all the lightning research UAH is actively pursuing," Dr. Bitzer said.
Après un appareil photo hybride avec une mise au point ultra rapide, Sony vient de dévoiler quelques nouveautés dans sa gamme HX qui regroupe principalement des appareils photo avec un zoom optique puissant. Pour cette annonce, ce sont les HX60V et HX400 qui se dévoilent.
Sony HX60V, le compact expert, complet, avec zoom optique 30x
Si les photographes avancés ne font pas la course au zoom, les photographes occasionnels aiment pouvoir capturer tout type de sujet et à toute distance avec un faible encombrement. La réponse de Sony à cette problématique est le HX60V, un produit complet et performant.
Présenté comme le compagnon idéal des voyageurs, le Sony HX60V est un appareil photo numérique compact équipé d'un capteur rétro-éclairé CMOS Exmor RTM accompagné d'une optique Sony G et un processeur de traitement BIONZ X. A titre de comparaison, ce processeur de traitement est annoncé comme 3 fois plus performant que celui du HX50V, ça promet. Pour une grande polyvalence, l'appareil propose un zoom 30x optique accompagné d'un système de stabilisation puissant sur 5 axes en vidéo Full HD.
Le HX60V propose également une connexion WiFi accompagnée du NFC pour un jumelage instantané avec l'application dédiée pouvant être installée sur smartphone ou tablette et non seulement Xperia. Le pilotage à distance de l'appareil photo est également possible. Grâce au WiFi, il est également possible d'installer des applications gratuites ou payantes PlayMemories Camera Apps. Le GPS est également de la partie sur le HX60V et non sur le HX60. Pour le reste, Sony annonce une autonomie de 380 photos ce qui est plutôt convenable et la sortie HDMI est capable de sortir des images en 4K.
Enfin, l'appareil photo sera commercialisé dans quelques jours à 380 euros en version HX60 sans GPS et 400 euros en HX60V avec puce GPS intégrée.
Sony HX400V, un bridge au zoom optique 50x
Si le marché du bridge n'est pas particulièrement actif dans le monde, les français ont encore un gros faible pour ces produits proposant le plus souvent un grand zoom avec une très bonne prise en main. Sony présente aujourd'hui son HX400V, un appareil photo numérique complet proposant un zoom optique Carl ZEISS Vario-Sonnar T* 50x avec fonction Clear Image Zoom 100x. Comme sur le précédent modèle présenté dans cet article, un système de stabilisation performant optique sur 5 axes est disponible.
Le bridge est également équipé d'un capteur CMOS Exmor RTM de 20,4 millions de pixels avec processeur de traitement d'image BIONZ X. En plus de proposer une prise en main de type reflex, l'appareil photo offre également un viseur électronique Tru-Finder (201 points) et propose des réglages manuels. Un écran orientable lui a également été greffé sur l'arrière pour faciliter la prise de vue à main levée.
Comme c'est à la mode chez Sony, le HX400V est également équipé d'une connexion WiFi accompagné du NFC One-Touch pour des transferts d'information rapides. Du côté des dimensions, cet appareil photo mesure 129,6 x 93,2 x 103,2 mm et proposera une autonomie d'environ 300 images.
Disponible à la vente au mois de mars, il faudra débourser 480 euros pour l'acquérir.
Vous vous dites Geek et vous n'avez pas encore entendu parler de Cube World ? Voilà un problème de taille qu'on se doit de réparer tout de suite. Mieux que de vous expliquer uniquement de quoi il s'agit, nous allons même vous donner nos premières impressions car, chez Hitek, nous l'avons déjà testé.
Cube World est le nouveau jeu qui fait un carton avant même la sortie de sa version définitive. En effet, le buzz a tellement été important que le jeu a subit une attaque "DDoS" soit une surcharge du site car les demandes de téléchargement ont été trop nombreuses d'un coup, et trop importante par rapport à ce qu'avaient prévu les développeurs. Et en parlant des développeurs du Cube World, il s'agit d'un couple (dans la vie comme dans le travail) qui ont développé seuls le jeu. D'un côté, Wollay s'est occupé de tout le développement du jeu et de l'autre son épouse qui a créé le design et les modèles des personnages. Côté puissance, le jeu est très léger et optimisé et ne nécessite donc pas une machine puissante pour jouer. Il est pour le moment disponible que sur Windows mais une version Mac et Linux est prévue. Disponible qu'en version alpha, les mises à jour sont très régulières et on sait déjà que les futurs ajouts seront, entre autres, de nouveaux environnements, de nouvelles classes, un mode de jeu MMORPG et du PvP (mode joueur contre joueur).
Il s'agit d'un jeu de type Sand box mais avec un graphisme à la RPG. Le jeu reprend le style graphique simpliste et cubique d'un Minecraft avec tout ce qui fait le charme des RPG : explorer un monde unique qui a la particularité d'être illimité car généré à la volée, créer son propre personnage en lui attribuant une race / une classe, mais aussi pouvoir monter en niveau et augmenter la puissance de son équipement et ses capacités (le levelling est illimité). Par exemple, un mage peut choisir la voie de l'eau ou celle du feu, et ainsi apprendre des capacités en rapport, c'est-à-dire l'explosion pour le feu et sorts de soin pour l'eau.
Après toutes ces précisions techniques, c'est l'heure pour nous de vous dire ce qu'on a pensé des premières heures de jeu sur Cube World. Nous avons joué 3-4 heures, fait une quinzaine de niveaux, à trois en ligne hébergé sur un PC personnel. Voici nos premières impressions :
- On ne voit pas le temps passer: un univers infini, pleins de choses a découvrir, et on s'habitue vite aux graphismes même pour ceux qui n'ont jamais joué à Minecraft.
- Le jeu est un peu compliqué au début. Pour ma part, j'ai choisi un mage qui est doté d'emblée de deux attaques souris, un sort faible et rapide, ainsi qu'un sort fort mais lent. On apparait dans un environnement forestier, c'est le niveau 1.
- Conseil : faire bien attention à son environnement dès le début. Notamment, chaque ennemi à une couleur ayant une signification sur son nom : blanc, il est moins fort que vous ; bleu, au même niveau ; orange, il commence à être fort et rouge, c'est la mort assurée !
- On peux immédiatement aller au village le plus proche pour se familiariser avec le jeu, parler aux perso non joueurs pour lancer des quêtes, observer qu'un système de crafting d'objet est présent (forge, machine à coudre, etc). Et plus on s'éloigne de son point de départ, plus les monstres sont forts !
- Il y a également des éléments de décors attaquables, tel que des buissons, des fleurs de coton. En les détruisant, on obtient des matériaux utilisables dans les forges et autres. On peux aussi ramasser des fleurs de coeurs qui permettront de fabriquer des potions de soins avec des fioles remplies d'eau.
- Après quelques monstres tués, qui vous donnent chaque fois quelques points d'expériences, parfois de l'argent ou des objets, j'obtiens quelque chose de particulier : un croissant. On m'explique alors que certains objets dans le jeu permettent de capturer un animal ! Je tends le croissant, prévu pour obtenir un chien, et au premier chien que je croise, j'ai un animal de compagnie. Lui aussi a des niveaux et il va m'aider contre les monstres pour me faciliter le jeu.
- Le passage à la nuit est vraiment très sombre et on n'y voit plus rien. Il faut absolument utiliser sa torche pour avancer et donc essayer d'avoir une torche rare pour y voir plus loin. Petite astuce : plus le village de départ est loin, plus la torche proposée par le vendeur est rare.
- On décide de faire notre premier donjon après une dizaine de niveaux gagnés, un animal valable, et quelques capacités montées. Je passe mage de l'eau, augmente mon sort de soin, prends la capacité d'utiliser un deltaplane, et enfin celui de pouvoir grimper sur mon animal pour marcher plus vite grâce à lui !
- Premier donjon : un château sous le sol, les monstres sont regroupés en petits pack. Il faut bouger tout le temps et bien soigner mes partenaires guerrier et archer. Nous croisons même un troll dans les couloirs qui tourbillonne sur nous avec sa massue (tourbilol !). Fin de donjon, un boss est là à nous attendre, un mage aussi. Après bien 5-10 minutes de combat, celui-ci meurt et laisse tomber des objets rares. Génial, l'équipement a des niveaux de rareté.
-Retour au village, on peux personnaliser son arme comme on le souhaite avec les matériaux récupérés précédemment : cube de bois pour les bâtons, cube de fer pour les épées etc...
- On termine notre session de jeu avec l'archer qui nous montre une petite astuce : il a une capacité qui lui permet de sauter en arrière, et couplé au deltaplane, il avance "à la vitesse de la lumière" au moins 10 fois plus vite que n'importe quel personnage.
Nous avons trouvé le jeu très addictif et vraiment très sympa. Tout a été pensé ! On pourrait y passer des heures, surtout que des sommes astronomiques d'ajouts sont prévus par son créateur. Seulement 15 euros pour tant de plaisir, on dit go go go ! Pour le télécharger, rendez-vous directement sur le site Pricroma.
Et voici les premières impressions en vidéo par Fanta (compter 22 minutes mais présentation top) :
