Posts belonging to Category electronics



How To Harvest More of the Sun’s Energy

As solar panels become less expensive and capable of generating more power, solar energy is becoming a more commercially viable alternative source of electricity. However, the photovoltaic cells now used to turn sunlight into electricity can only absorb and use a small fraction of that light, and that means a significant amount of solar energy goes untapped.

A new technology created by researchers from Caltech, and described in a paper published online in Science Express, represents a first step toward harnessing that lost energy.

Sunlight is composed of many wavelengths of light. In a traditional solar panel, silicon atoms are struck by sunlight and the atoms’ outermost electrons absorb energy from some of these wavelengths of sunlight, causing the electrons to get excited. Once the excited electrons absorb enough energy to jump free from the silicon atoms, they can flow independently through the material to produce electricity. This is called the photovoltaic effect—a phenomenon that takes place in a solar panel‘s photovoltaic cells.

Although silicon-based photovoltaic cells can absorb light wavelengths that fall in the visible spectrum—light that is visible to the human eye—longer wavelengths such as infrared light pass through the silicon. These wavelengths of light pass right through the silicon and never get converted to electricity — and in the case of infrared, they are normally lost as unwanted heat.

nanospheres
An ultra-sensitive needle measures the voltage that is generated while the nanospheres are illuminated

The silicon absorbs only a certain fraction of the spectrum, and it’s transparent to the rest. If I put a photovoltaic module on my roof, the silicon absorbs that portion of the spectrum, and some of that light gets converted into power. But the rest of it ends up just heating up my roof,” says Harry A. Atwater, Professor of Applied Physics at the Resnick Sustainability Institute, who led the study. Now, Atwater and his colleagues have found a way to absorb and make use of these infrared waves with a structure composed not of silicon, but entirely of metal.

The new technique they’ve developed is based on a phenomenon observed in metallic structures known as plasmon resonance. Plasmons are coordinated waves, or ripples, of electrons that exist on the surfaces of metals at the point where the metal meets the air. While the plasmon resonances of metals are predetermined in nature, Atwater and his colleagues found that those resonances are capable of being tuned to other wavelengths when the metals are made into tiny nanostructures in the lab.

Normally in a metal like silver or copper or gold, the density of electrons in that metal is fixed; it’s just a property of the material,” Atwater says. “But in the lab, I can add electrons to the atoms of metal nanostructures and charge them up. And when I do that, the resonance frequency will change.”

We’ve demonstrated that these resonantly excited metal surfaces can produce a potential“—an effect very similar to rubbing a glass rod with a piece of fur: you deposit electrons on the glass rod. “You charge it up, or build up an electrostatic charge that can be discharged as a mild shock,” he says. “So similarly, exciting these metal nanostructures near their resonance charges up those metal structures, producing an electrostatic potential that you can measure.” This electrostatic potential is a first step in the creation of electricity, Atwater says. “If we can develop a way to produce a steady-state current, this could potentially be a power source.” He envisions a solar cell using the plasmoelectric effect someday being used in tandem with photovoltaic cells to harness both visible and infrared light for the creation of electricity.

Source: http://www.caltech.edu/

Control Google Glass Directly By Your Mind

The british company This Place wants to change the future of usability for everyone. As a digital design agency, they are acutely aware of the importance of accessibility and potential for digital technologies to enhance the lives of millions of people who live with disabilities. In order to make a difference, the company focus on cutting out the need for a high level of dexterity to operate computers, and instead focus on utilising the power of the mind. Basically the device called MindRDR read brain waves in your mind.

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Do you want to take a pic and to send it to your friends through Twitter? MindRDR will read the waves of your mind and operates the internet commands for you using your Google Glass.

mindRDR

Next step: control a computer remotely just with your mind, or just as you use an imaginary keyboard to control your computer

The mindRDR and the NeuroSky MindWave system could be great news for all humans stuck paralyzed in wheel chairs.

Source: http://www.thisplace.com/

S Hawking: highly intelligent machines, the “worst mistake in history”

Dismissing the implications of highly intelligent machines could be humankind’s “worst mistake in history“, write astrophysicist Stephen Hawking, computer scientist Stuart Russell, and physicists Max Tegmark and Frank Wilczek in the Independent. “Self-awaremachines have received the Hollywood treatment in the Johnny Depp film Transcendence, but the subject should receive serious consideration, they say.

Successfully creating artificial intelligence would be “the biggest event in human history“, they write, and the possible benefits for everyday human life are enormous. There could come a time, however, when machines outpace human achievement. If and when that day arrives, they wonder, will the best interest of humans still factor into their calculations?
terminator
One can imagine such technology outsmarting financial markets, out-inventing human researchers, out-manipulating human leaders, and developing weapons we cannot even understand,” they write. “Whereas the short-term impact of AI depends on who controls it, the long-term impact depends on whether it can be controlled at all.”

And what are we humans doing to address these concerns, they ask. Nothing.

All of us should ask ourselves what we can do now to improve the chances of reaping the benefits and avoiding the risks,” they conclude.

A while back, we wondered about the implications of machine journalists. But maybe we should just be thankful that at least something will be around to write long-form essays on the last days of humankind.

Source: http://www.bbc.com/

Graphene soaks up Carbon, Cause of Global Warming

Chemists and engineers at Oregon State University (OSU) have discovered a fascinating new way to take some of the atmospheric carbon dioxide that’s causing the greenhouse effect and use it to make an advanced, high-value material for use in energy storage products.This innovation in nanotechnology won’t soak up enough carbon to solve global warming, researchers say. However, it will provide an environmentally friendly, low-cost way to make nanoporous graphene for use in “supercapacitors” – devices that can store energy and release it rapidly. Such devices are used in everything from heavy industry to consumer electronics.

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There are other ways to fabricate nanoporous graphene, but this approach is faster, has little environmental impact and costs less,” said Xiulei (David) Ji, an OSU assistant professor of chemistry in the OSU College of Science and lead author on the study. “The product exhibits high surface area, great conductivity and, most importantly, it has a fairly high density that is comparable to the commercial activated carbons. “And the carbon source is carbon dioxide, which is a sustainable resource, to say the least,” Ji said. “This methodology uses abundant carbon dioxide while making energy storage products of significant value.”

The findings were just published in Nano Energy by scientists from the OSU College of Science, OSU College of Engineering, Argonne National Laboratory, the University of South Florida and the National Energy Technology Laboratory in Albany, Ore. The work was supported by OSU.

Source: http://oregonstate.edu/

A Billion Holes Make a Postage Stamp Battery

Researchers at the University of Maryland (UMD) have invented a single tiny structure that includes all the components of a battery that they say could bring about the ultimate miniaturization of energy storage components.
nanopores
A billion nanopores could fit on a postage stamp
The structure is called a nanopore: a tiny hole in a ceramic sheet that holds electrolyte to carry the electrical charge between nanotube electrodes at either end. The existing device is a test, but the bitsy battery performs well. First author Chanyuan Liu, a Ph.D. student in materials science, says that it can be fully charged in 12 minutes, and it can be recharged thousands of time.

Many millions of these nanopores can be crammed into one larger battery the size of a postage stamp. One of the reasons the researchers think this unit is so successful is because each nanopore is shaped just like the others, which allows them to pack the tiny thin batteries together efficiently.The space inside the holes is so small that the space they take up, all added together, would be no more than a grain of sand.
Now that the scientists have the battery working and have demonstrated the concept, they have also identified improvements that could make the next version 10 times more powerful. The next step to commercialization: the inventors have conceived strategies for manufacturing the battery in large batches.

A team of UMD chemists and materials scientists collaborated on the project: Gary Rubloff, director of the Maryland NanoCenter, Sang Bok Lee, a professor in the Department of Chemistry and seven of their Ph.D. students.
Source: http://www.umdrightnow.umd.edu/

Electric Car Batteries Charged In A Few Minutes For 500 km Range

A car powered by its own body panels could soon be driving on our roads after a breakthrough in nanotechnology research by a team from the Queensland Institute of Technology (QUT) in Australia. Researchers have developed lightweight and cheap “supercapacitors” that can be combined with regular batteries to dramatically boost the power of an electric car.
The discovery was made by Dr Jinzhang Liu, Professor Nunzio Motta and PhD researcher Marco Notarianni, from QUT, and fellows from Rice University in Houston, in the United States.
The supercapacitors – a “sandwich” of electrolyte between two all-carbon electrodes – were made into a thin and extremely strong film with a high power density.
The film could be embedded in a car’s body panels, roof, doors, bonnet and floorstoring enough energy to turbocharge an electric car’s battery in just a few minutes.
ElectricCARSAfter one full charge this car should be able to run up to 500km (310 miles) – similar to a petrol-powered car and more than double the current limit of an electric car
Supercapacitors offer a high power output in a short time, meaning a faster acceleration rate of the car and a charging time of just a few minutes, compared to several hours for a standard electric car battery.”
In the future, it is hoped the supercapacitor will be developed to store more energy than a Li-Ion battery while retaining the ability to release its energy up to 10 times faster – meaning the car could be entirely powered by the supercapacitors in its body panels, Mr Notarianni said.

The findings, published in the Journal of Power Sources and the Nanotechnology journal, mean a car partly powered by its own body panels could be a reality within five years, Mr Notarianni said.
Source; https://www.qut.edu.au/

Fuel Cells For Hydrogen-powered Car

University of Utah engineers developed the first room-temperature fuel cell that uses enzymes to help jet fuel produce electricity without needing to ignite the fuel. These new fuel cells can be used to power portable electronics, off-grid power and sensors.

Fuel cells convert energy into electricity through a chemical reaction between a fuel and an oxygen-rich source such as air. If a continuous flow of fuel is provided, a fuel cell can generate electricity cleanly and cheaply. While batteries are used commonly to power electric cars and generators, fuel cells also now serve as power generators in some buildings, or to power fuel-cell vehicles such as prototype hydrogen-powered cars (See: http://nanocomputer.com/).

Tucson fuel cell
The major advance in this research is the ability to use Jet Propellant-8 (JP-8) directly in a fuel cell without having to remove sulfur impurities or operate at very high temperature,” says the study’s senior author, Shelley Minteer, a University of Utah professor of materials science and engineering, and also chemistry. “This work shows that JP-8 and probably others can be used as fuels for low-temperature fuel cells with the right catalysts.” Catalysts are chemicals that speed reactions between other chemicals.
A study of the new cells appears online today in the American Chemical Society journal ACS Catalysis.

Source: http://unews.utah.edu/

NanoRobots Manufacture Devices At NanoScale

What does it take to fabricate electronic and medical devices tinier than a fraction of a human hair? Nanoengineers at the University of California, San Diego recently invented a new method of lithography in which nanoscale robots swim over the surface of light-sensitive material to create complex surface patterns that form the sensors and electronics components on nanoscale devices. Their research, published recently in the journal Nature Communications, offers a simpler and more affordable alternative to the high cost and complexity of current state-of-the-art nanofabrication methods such as electron beam writing.
Led by distinguished nanoengineering professor and chair Joseph Wang, the team developed nanorobots, or nanomotors, that are chemically-powered, self-propelled and magnetically controlled. Their proof-of-concept study demonstrates the first nanorobot swimmers able to manipulate light for nanoscale surface patterning. The new strategy combines controlled movement with unique light-focusing or light-blocking abilities of nanoscale robots.

nanorobotNanoengineers have invented a spherical nanorobot made of silica that focuses light like a near-field lens to write surface patterns for nanoscale devices. In this image, the red and purple areas indicate where the light is being magnified to produce a trench pattern on light-sensitive material

All we need is these self-propelled nanorobots and UV light,” said Jinxing Li, a doctoral student at the Jacobs School of Engineering and first author. “They work together like minions, moving and writing and are easily controlled by a simple magnet.

Source: http://www.jacobsschool.ucsd.edu/

Nano Light Consumes Hundred Times Less Than A LED

Scientists from Tohoku University in Japan have developed a new type of energy-efficient flat light source based on carbon nanotubes with very low power consumption of around 0.1 Watt for every hour‘s operation — about a hundred times lower than that of an LED. Electronics based on carbon, especially carbon nanotubes (CNTs), are emerging as successors to silicon for making semiconductor materials, And they may enable a new generation of brighter, low-power, low-cost lighting devices that could challenge the dominance of light-emitting diodes (LEDs) in the future and help meet society’s ever-escalating demand for greener bulbs.
nanolightPlane-lighting homogeneity image of a planar light source device through a neutral density filter
Our simple ‘diode’ panel could obtain high brightness efficiency of 60 Lumen per Watt, which holds excellent potential for a lighting device with low power consumption,” said Norihiro Shimoi, the lead researcher and an associate professor of environmental studies at the Tohoku University. “We have found that a cathode with highly crystalline single-walled carbon nanotubes and an anode with the improved phosphor screen in our diode structure obtained no flicker field emission current and good brightness homogeneity,” Shimoi said.
Source: http://www.aip.org/

Electric Car: Hydrogen Fuel Cells 40 Times Cheaper

Researchers from Umea University – Sweden – and chinese collegues show how a unique nano-alloy composed of palladium nano-islands embedded in tungsten nanoparticles creates a new type of catalysts for highly efficient oxygen reduction, the most important reaction in hydrogen fuel cells. Fuel cell systems represent a promising alternative for low carbon emission energy production. Traditional fuel cells are however limited by the need of efficient catalysts to drive the chemical reactions involved in the fuel cell. Historically, platinum and its alloys have frequently been used as anodic and cathodic catalysts in fuel cells, but the high cost of platinum, due to its low abundance, motivates researchers to find efficient catalysts based on earth-abundant elements. The explanation for the very high efficiency is the unique morphology of the alloy. It is neither a homogeneous alloy, nor a fully segregated two-phase system, but rather something in between.

hydrogen fuel cellsCaption: A schematic model of the unique morphology of the alloy. The Pd-islands (light-brown spheres) are embedded in an environment of tungsten (blue spheres). Oxygen are represented by red spheres, and hydrogen by white spheres.

In our study we report a unique novel alloy with a palladium (Pd) and tungsten (W) ratio of only one to eight, which still has similar efficiency as a pure platinum catalyst. Considering the cost, it would be 40 times lower,” says Thomas Wågberg, Senior lecturer at Department of Physics, Umeå University.
The unique formation of the material is based on a synthesis method, which can be performed in an ordinary kitchen micro-wave oven purchased at the local supermarket. If we were not using argon as protective inert gas, it would be fully possible to synthesize this advanced catalyst in my own kitchen! ,” says Thomas Wågberg.
The findings are published in the scientific journal Nature Communications.

Source: http://www.teknat.umu.se/