Graphene supports a ratchet motion of electrons when placed in a magnetic field

http://www.nanowerk.com/news2/newsid=29166.php

Graphene supports a ratchet motion of electrons when placed in a magnetic field

(Nanowerk News) A ratchet supports one-way traffic. One can pull it back and forth, but it only moves forwards. Mechanical ratchets, used to pull or hold heavy objects, are familiar examples. Also, some electronic devices are based on ratchets. Transistors are made out of diodes, which rectify electrical currents: however hard one pushes electrons in both directions, they flow only in one. Now an international consortium consisting of research groups from Germany, Russia, Sweden, and the U.S., led by the experimental group of Prof. Dr. Sergey Ganichev from the University of Regensburg and supported by the theoretical group of Prof. Dr. Sergey Tarasenko (St. Petersburg) and Prof. Dr. Jaroslav Fabian (Regensburg), has demonstrated that electronic ratchets can be successfully scaled down to one-atom thick layers.
The researchers showed that graphene, a single layer of carbon atoms arranged in a honeycomb lattice, supports a ratchet motion of electrons when placed in a magnetic field. They applied terahertz laser fields to push the electrons back and forth, while the magnetic field acted as a valve to let only those electrons moving in one direction go on, stopping the others. The results of the research group are reported in an issue ofNature Nanotechnology ("Magnetic quantum ratchet effect in graphene").
Graphene may be the ultimate electronic material, possibly replacing silicon in electronic devices in the future. It has attracted worldwide attention from physicists, chemists, and engineers. Its discoverers, A. Geim and K. Novoselov, were awarded the physics Nobel Prize for it in 2010. The discovery of the ratchet motion in graphene greatly adds to the technological potential of this material and to the prospects of further miniaturization of electronic devices. Before carbon based electronics might take over from silicon many fundamental physical challenges need to be addressed.
In Regensburg, research activities on graphene are embedded in larger research programs, funded by the German Science Foundation (DFG). These are a PhD program on carbon based electronics (DFG-Research Training Group GRK 1570, spokesperson: Prof. Dr. Milena Grifoni) and a Collaborative Research Center (SFB 689, spokesperson: Prof. Dr. Dieter Weiss) funding more than 40 PhD students, as well as projects within a DFG Priority Programm (SPP 1459, spokesperson: Prof. Dr. Thomas Seyller, Chemnitz). The international cooperation on terahertz physics and technology is coordinated by the Regensburg Terahertz Center (TerZ, directed by Prof. Dr. Sergey Ganichev), also funded by the International Bureau of the German Ministry of Education and Research.
Source: University of Regensburg

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Posted: Feb 18th, 2013

World Economic Forum identifies top 10 emerging technologies for 2013

(Nanowerk News) New challenges need new technologies to tackle them. Here, the World Economic Forum’s Global Agenda Council on Emerging Technologies identifies the top 10 most promising technology trends that can help to deliver sustainable growth in decades to come as global population and material demands on the environment continue to grow rapidly. These are technologies that the Council considers have made development breakthroughs and are nearing large-scale deployment.

OnLine Electric Vehicles (OLEV) Wireless technology can now deliver electric power to moving vehicles. In next-generation electric cars, pick-up coil sets under the vehicle floor receive power remotely via an electromagnetic field broadcast from cables installed under the road. The current also charges an onboard battery used to power the vehicle when it is out of range. As electricity is supplied externally, these vehicles need only a fifth of the battery capacity of a standard electric car, and can achieve transmission efficiencies of over 80%. Online electric vehicles are currently undergoing road tests in Seoul, South Korea.

3-D printing and remote manufacturing Three-dimensional printing allows the creation of solid structures from a digital computer file, potentially revolutionizing the economics of manufacturing if objects can be printed remotely in the home or office. The process involves layers of material being deposited on top of each other in to create free-standing structures from the bottom up. Blueprints from computer-aided design are sliced into cross-section for print templates, allowing virtually created objects to be used as models for “hard copies” made from plastics, metal alloys or other materials.

Self-healing materials One of the defining characteristics of living organisms is their inherent ability to repair physical damage. A growing trend in biomimicry is the creation of non-living structural materials that also have the capacity to heal themselves when cut, torn or cracked. Self-healing materials which can repair damage without external human intervention could give manufactured goods longer lifetimes and reduce the demand for raw materials, as well as improving the inherent safety of materials used in construction or to form the bodies of aircraft.

Energy-efficient water purification Water scarcity is a worsening ecological problem in many parts of the world due to competing demands from agriculture, cities and other human uses. Where freshwater systems are over-used or exhausted, desalination from the sea offers near-unlimited water but a considerable use of energy – mostly from fossil fuels – to drive evaporation or reverse-osmosis systems. Emerging technologies offer the potential for significantly higher energy efficiency in desalination or purification of wastewater, potentially reducing energy consumption by 50% or more. Techniques such as forward-osmosis can additionally improve efficiency by utilizing low-grade heat from thermal power production or renewable heat produced by solar-thermal geothermal installations.

Carbon dioxide (CO2) conversion and use Long-promised technologies for the capture and underground sequestration of carbon dioxide have yet to be proven commercially viable, even at the scale of a single large power station. New technologies that convert the unwanted CO2 into saleable goods can potentially address both the economic and energetic shortcomings of conventional CCS strategies. One of the most promising approaches uses biologically engineered photosynthetic bacteria to turn waste CO2 into liquid fuels or chemicals, in low-cost, modular solar converter systems. Individual systems are expected to reach hundreds of acres within two years. Being 10 to 100 times as productive per unit of land area, these systems address one of the main environmental constraints on biofuels from agricultural or algal feedstock, and could supply lower carbon fuels for automobiles, aviation or other big liquid-fuel users.

Enhanced nutrition to drive health at the molecular level Even in developed countries millions of people suffer from malnutrition due to nutrient deficiencies in their diets. Now modern genomic techniques can determine at the gene sequence level the vast number of naturally consumed proteins which are important in the human diet. The proteins identified may have advantages over standard protein supplements in that they can supply a greater percentage of essential amino acids, and have improved solubility, taste, texture and nutritional characteristics. The large-scale production of pure human dietary proteins based on the application of biotechnology to molecular nutrition can deliver health benefits such as muscle development, managing diabetes or reducing obesity.

Remote sensing The increasingly widespread use of sensors that allow often passive responses to external stimulae will continue to change the way we respond to the environment, particularly in the area of health. Examples include sensors that continually monitor bodily function – such as heart rate, blood oxygen and blood sugar levels – and, if necessary, trigger a medical response such as insulin provision. Advances rely on wireless communication between devices, low power-sensing technologies and, sometimes, active energy harvesting. Other examples include vehicle-to-vehicle sensing for improved safety on the road.

Precise drug delivery through nanoscale engineering Pharmaceuticals that can be precisely delivered at the molecular level within or around a diseased cell offer unprecedented opportunities for more effective treatments while reducing unwanted side effects. Targeted nanoparticles that adhere to diseased tissue allow for the micro-scale delivery of potent therapeutic compounds while minimizing their impact on healthy tissue, and are now advancing in medical trials. After almost a decade of research, these new approaches are finally showing signs of clinical utility.

Organic electronics and photovoltaics Organic electronics – a type of printed electronics – is the use of organic materials such as polymers to create electronic circuits and devices. In contrast to traditional (silicon-based) semiconductors that are fabricated with expensive photolithographic techniques, organic electronics can be printed using low-cost, scalable processes such as ink jet printing, making them extremely cheap compared with traditional electronics devices, both in terms of the cost per device and the capital equipment required to produce them. While organic electronics are currently unlikely to compete with silicon in terms of speed and density, they have the potential to provide a significant edge in cost and versatility. The cost implications of printed mass-produced solar photovoltaic collectors, for example, could accelerate the transition to renewable energy.

Fourth-generation reactors and nuclear-waste recycling Current once-through nuclear power reactors use only 1% of the potential energy available in uranium, leaving the rest radioactively contaminated as nuclear “waste”. While the technical challenge of geological disposal is manageable, the political challenge of nuclear waste seriously limits the appeal of this zero-carbon and highly scalable energy technology. Spent-fuel recycling and breeding uranium-238 into new fissile material – known as Nuclear 2.0 – would extend already-mined uranium resources for centuries while dramatically reducing the volume and long-term toxicity of wastes, whose radioactivity will drop below the level of the original uranium ore on a timescale of centuries rather millennia. This makes geological disposal much less of a challenge (and arguably even unnecessary) and nuclear waste a minor environmental issue compared to hazardous wastes produced by other industries. Fourth-generation technologies, including liquid metal-cooled fast reactors, are now being deployed in several countries and are offered by established nuclear engineering companies.

This list has been compiled by the World Economic Forum’s Global Agenda Council on Emerging Technologies, of which David King is currently chair. For a full list of the Council’s members see here

Source: World Economic Forum

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The Music Man | Steve James

from Focus Forward Films PRO 5 months ago NOT YET RATED

MUSIC MAN tells the story of professor and inventor Ge Wang who teaches computer music at Stanford University where he began the innovative Stanford Laptop Orchestra. Wang believes everyone who loves music should be able to play it. To that end, Wang was the first to turn the IPhone into a musical instrument when he created the “Ocarina” phone app which became one of the most popular in the world when it was launched in 2009.

Join the conversation and tweet #MusicManDoc to have your tweet featured on the GE FOCUS FORWARD website. Go tofocusforwardfilms.com/films/63/the-music-man to see the discussion.

Watch more GE FOCUS FORWARD films at vimeo.com/focusforwardfilms/films.

A NONFICTION production
Director: Steve James
Producer: Max Fink
Editor: Steve James
Photographed by Josh Salzman
Sound Recordist: Dan Jasper
Gaffers: Frank Strzalkowski and Lisa Quinn
Grip/pa: Adan Pulido
Assistant Editor: Nora Gully
Thanks: GE Wang, Jeff Smith, Stephanie Lai, Turner Kirk, Patrick Degan, CCRMA, Stanford, Smule

The Auto-Tune Effect | Stanley Nelson

from Focus Forward Films PRO 7 months ago NOT YET RATED

You’re humming along, tapping your toe, maybe nodding your head, listening to your favorite song, the artist’s vocals ascending higher and higher up the scale to that heart-stopping, tear inducing pitch perfect note. Flawless. Inhuman? Auto-tune is transforming music. Listening will never be the same.

Join the conversation and tweet #AutoTuneDoc to have your tweet featured on the GE FOCUS FORWARD website. Go tofocusforwardfilms.com/films/43/the-auto-tune-effect to see the discussion.

Watch more GE FOCUS FORWARD films at vimeo.com/focusforwardfilms/films.

Director: Stanley Nelson
Producer: Cyndee Readdean
Editor: Lewis Erskine
Directors of Photography: Dan Huiting, Owen Bissell, Christopher Wiggins, Eli Ljung

Speaking With Light | Alex Gibney on Vimeo

Speaking With Light | Alex Gibney

from Focus Forward Films PRO 5 months ago NOT YET RATED

Dr Edie Widder takes us on a journey deep under the sea. She’s used pioneering research with bioluminescent sea creatures to help us shine a light on the levels of pollution we’re producing above the ground. Edie’s love of the sea - and the simplicity of good science - shine through this journey of wonder.

Join the conversation and tweet #LightsTalk to have your tweet featured on the GE FOCUS FORWARD website. Go tofocusforwardfilms.com/films/58/speaking-with-light to see the discussion.

Watch more GE FOCUS FORWARD films at vimeo.com/focusforwardfilms/films

DIRECTOR: Alex Gibney
PRODUCER: Alexis Bloom
EDITOR: Marc Vives
PHOTOGRAPHY: Dr Edith Widder and ORCA – teamorca.org
TIMELAPSE PHOTOGRAPHY: Colin Rich
MUSIC: Ghost

Graphene supercapacitors are 20 times as powerful, can be made with a DVD burner | ExtremeTech

http://www.extremetech.com/extreme/122763-graphene-supercapacitors-are-20-times-as-powerful-can-be-made-with-a-dvd-burner

• By Sebastian Anthony on March 19, 2012 at 8:05 am
• 31 Comments

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A team of international researchers have created graphene supercapacitors using a LightScribe DVD burner. These capacitors are both highly flexible (pictured below) and have energy and power densities far beyond existing electrochemical capacitors, possibly within reach of conventional lithium-ion and nickel metal hydride batteries.

The team, which was led by Richard Kaner of UCLA, started by smearing graphite oxide — a cheap and very easily produced material — films on blank DVDs. These discs are then placed in a LightScribe drive (a consumer-oriented piece of gear that costs less than $50), where a 780nm infrared laser reduces the graphite oxide to pure graphene. The laser-scribed graphene (LSG) is peeled off and placed on a flexible substrate, and then cut into slices to become the electrodes. Two electrodes are sandwiched together with a layer of electrolyte in the middle — and voila, a high-density electrochemical capacitor, orsupercapacitor as they’re more popularly known.

Now, beyond the novel manufacturing process — the scientists are confident it can be scaled for commercial applications, incidentally — the main thing about LSG capacitors is that they have very desirable energy and power characteristics. Power-wise, LSG supercapacitors are capable of discharging at 20 watts per cm³, some 20 times higher than standard activated carbon capacitors, and three orders of magnitude higher than lithium-ion batteries. Energy-wise, we’re talking about 1.36 milliwatt-hours per cm³, about twice the density of activated carbon, and comparable to a high-power lithium-ion battery.

These characteristics stem from the fact thatgraphene is the most conductive material known to man — the LSG produced by the scientists showed a conductivity of 1738 siemens per meter (yes, that’s a real unit), compared to just 100 siemens for activated carbon. The performance of capacitors is almost entirely reliant on the surface area of the electrodes, so it’s massively helpful that one gram of LSG has a surface area of 1520 square meters (a third of an acre). As previously mentioned, LSG capacitors are highly flexible, too, with no effect on its performance (pictured right).

These graphene supercapacitors could really change the technology landscape. While computing power roughly doubles every 18 months, battery technology is almost at a standstill. Supercapacitors, which suffer virtually zero degradation over 10,000 cycles or more, have been cited as a possible replacement for low-energy devices, such as smartphones. With their huge power density, supercapacitors could also revolutionizeelectric vehicles, where huge lithium-ion batteries really struggle to strike a balance between mileage, acceleration, and longevity. It’s also worth noting, however, that lithium-ion batteries themselves have had their capacity increased by 10 times thanks to the addition of graphene. Either way, then, graphene seems like it will play a major role in the future of electronics.

Read more at Science (paywalled)

[Image credit]

The Super Supercapacitor | Brian Golden Davis on Vimeo

THE SUPER SUPERCAPACITOR is a Finalist in the $200,000 GE FOCUS FORWARD Filmmaker Competition. Learn more about the Competition and FOCUS FORWARD at focusforwardfilms.com Ric…

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Hilary Mantel · Royal Bodies · LRB 21 February 2013

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At least 3,000 died in residential schools, research shows - Canada - CBC News

At least 3,000 children, including four under the age of 10 found huddled together in frozen embrace, are now known to have died while they were attending Canada's aboriginal residential schools, according to new unpublished research.

via cbc.ca

#P4SPChat Recap: Cognitive Computing

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Exxon, You Can't Silence Us: A Public Letter

A crowdfunded Climate Change PSA was supposed to air on Fox - until Exxon threatened it off-air at the last minute. Let Exxon know: YOU CAN'T SILENCE US.

via other98.com