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Friday, 30 September 2011

Scientists and engineers create the ‘perfect plastic’

University of Leeds
Sept 30, 2011

Researchers at the University of Leeds and Durham University have solved a long-standing problem that could revolutionise the way new plastics are developed.

The breakthrough will allow experts to create the 'perfect plastic' with specific uses and properties by using a high-tech 'recipe book'. It will also increase our ability to recycle plastics. The research is published in the journal Science.

The paper's authors form part of the Microscale Polymer Processing project, a collaboration between academics and industry experts which has spent 10 years exploring how to better build giant 'macromolecules'. These long tangled molecules are the basic components of plastics and dictate their properties during the melting, flowing and forming processes in plastics production.

Low-density polyethylenes (LDPEs) are used in trays and containers, lightweight car parts, recyclable packaging and electrical goods. Up until now, industry developed a plastic then found a use for it, or tried hundreds of different "recipes" to see which worked. This method could save the manufacturing industry time, energy and money.

The mathematical models used put together two pieces of computer code. The first predicts how polymers will flow based on the connections between the string-like molecules they are made from. A second piece of code predicts the shapes that these molecules will take when they are created at a chemical level. These models were enhanced by experiments on carefully synthesised 'perfect polymers' created in labs of the Microscale Polymer Processing project.
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World's first energy-storage membrane outstrips existing rechargeable batteries and supercapacitors

Sept 30, 2011

The cost-effective and environmentally-friendly energy-storage membrane developed by NUS researchers 

Researchers from the NUS Nanoscience and Nanotechnology Initiative (NUSNNI) have developed the world's first energy-storage membrane, answering the need for cost-effective and environmentally friendly energy storage and delivery solutions.

The research team, led by Principal Investigator Dr Xie Xian Ning, used a polystyrene-based polymer to deposit the soft, foldable membrane converted from organic waste which, when sandwiched between and charged by two graphite plates, can store charge at 0.2 farads per square centimetre. This capability was well above the typical upper limit of 1 microfarad per square centimetre for a standard capacitor. The cost involved in energy storage is also drastically reduced with this invention, from about US$7 to store each farad using existing technologies based on liquid electrolytes to about US$0.62 per farad.

Dr Xie said: "Compared to rechargeable batteries and supercapacitors, the proprietary membrane allows for very simple device configuration and low fabrication cost. Moreover, the performance of the membrane surpasses those of rechargeable batteries, such as lithium ion and lead-acid batteries, and supercapacitors."

Supported by grants from the Singapore-MIT Alliance for Research & Technology (SMART) and the National Research Foundation, the research took about one and a half years to reach its current status and the team has also successfully filed a US patent for this novel invention.

The discovery has also attracted the attention of scientific journals worldwide, and was featured in Energy & Environmental Science and highlighted by renowned international journal Nature.

"With the advent of our novel membrane, energy storage technology will be more accessible, affordable, and producible on a large scale. It is also environmentally-friendly and could change the current status of energy technology," Dr Xie said.

Going forward, the team will explore more applications for this efficient energy storage solution. It is also looking into opportunities to work with venture capitalists to commercialise the invention.

Source: National University of Singapore

Automotive manufacturer Unveil New Hybrid Systems

Sept 30, 2011

Hybrid cars normally combine conventional engines with battery-powered electric motors. But many carmakers are developing alternative types of hybrids—some of which were on display this month at the Frankfurt Motor Show in Germany.

Hybrid systems recover kinetic energy—from the engine or from the vehicle itself—and use it to boost the efficiency of the engine. A typical hybrid car does this by charging up a battery.

Scuderi, based in West Springfield, Massachusetts, has altered the way the internal combustion engine operates to convert kinetic energy into the potential energy of high-pressure air. It splits the four parts of the internal combustion cycle across two cylinders synchronized on the same crankshaft. One cylinder handles the air intake and compression part of the cycle, pumping compressed air via a crossover passage into the second cylinder. The crossover contains the fuel-injection system, and combustion and exhaust are handled in the second cylinder.

When the vehicle does not need power—when traveling downhill, braking, or decelerating—the second cylinder is disabled and the first cylinder's air is diverted into a high-pressure air-storage tank. This air can be used to help run the engine, boosting its efficiency.

Recently, Scuderi has combined this system with a "Miller-cycle" turbocharger, which picks up energy off the exhaust and uses it to compress air into the intake cylinder. This allows the compression side to be shrunk down and reduces the amount of work done through the crankshaft. "The engine is producing much higher output at higher efficiency, we're producing less emissions, and our torque level is very high," said Scuderi group president Sal Scuderi at the Frankfurt show. "Our gasoline engine will rival the torque of any diesel engine on the market, but it does that while maintaining low pressure inside the cylinders, which reduces wear and tear."

Scuderi has now released results of a computer simulation of its engine against a European economy-class engine of comparable power. The air hybrid achieved a fuel economy figure of 65 miles per gallon, compared with 52 miles per gallon for the conventional engine. It also emitted 85 grams per kilometer of carbon dioxide, compared with 104 grams per kilometer for the conventional engine.

Across the Atlantic, a team that formerly worked for the Renault Formula 1 team has adapted its motorsport-developed flywheel system for use with conventional vehicles. The team has formed a company, Flybrid Systems, to commercialize the technology, and has teamed up with Jaguar Land Rover to trial the Flybrid technology that was originally developed as the kinetic energy recovery system (KERS) used in Formula 1 racing to provide a boost during racing. But while most KERS systems work by using a flywheel to charge an onboard battery or supercapacitor, Flybrid uses a gearbox system to transfer kinetic energy directly to and from the wheels.

Flybrid cars transfer energy via either a continuously variable transmission or a less complex three-gear system, which allows 15 different gear ratios on a standard five-gear model. "There are always efficiency losses when you convert energy," explains Flybrid's technical director, Doug Cross. "This system eliminates those losses, making it far more efficient."

The flywheel weighs five kilograms and is made from carbon fiber wrapped around a steel core. Because it is so light, it has to spin fast—at 60,000 rpm—which means that its rim is traveling at supersonic speeds. As a result, it has to operate in a vacuum, and Flybrid has developed special seals so that the wheel can be fully enclosed inside a safety container in case of a crash. At top speed, the flywheel can store 540 kilojoules of energy, which is sufficient to accelerate an average-sized automobile from a standing start to 48 kilometers per hour.

"One way you can use this technology is to boost the car during a cruise," Cross said. "We have a system installed on a Jaguar saloon, and that has shown that during a cruise, you can actually switch the engine off for 65 percent of the journey. With a V6 diesel engine, it cuts fuel use by 26 percent, but gives you the power of a V8 petrol engine."

Source: Technology Review

Nissan's Cars Will Read Your Mind

Sept 30, 2011

In the future--don't ask how distant--your car may be able to read your mind.

Nissan announced that it would be collaborating with the École Polytechnique Fédérale de Lausanne in Switzerland (EPFL) on a car that would be able to make an educated guess about what a driver's intentions are. The idea isn't quite to have a car be steered by the driver's mind alone--as in this German concept proposing that a car brake for you, based on brain signals. Rather, the car would read the driver's mind and prepare itself for a manually executed maneuver. Think about turning to the right, for instance, and the car will adopt the appropriate speed and road position.

How could a car know what you're thinking? For one thing, it would use brain-computer interface (BCI) technology developed at EPFL. The Swiss researchers, led by Professor José del R. Millán, are acknowledged leaders in this space, having created an interface that enables the steering of a wheelchair (first video)by thought alone, for instance.

But the car would read more than the driver's mind. The car's sensors could scan around the car itself, effectively cross-checking what the driver is thinking with what's actually out there. You may want to turn left--but if there's a Mack truck in your blind spot, your car will know better. By combining brain and environmental data, the car (and driver) makes smarter choices. "The idea is to blend driver and vehicle intelligence together in such a way that eliminates conflicts between them, leading to a safer motoring environment," José del R. Millán recently said.

EPFL isn't the first academic institution to dabble in hands-free driving. A German university-- Freie Universität Berlin--got there first.

But to the best of my knowledge, this is the first time a major car manufacturer has joined the effort, bringing the research into the realm of commercial, mass-market reality. The EPFL collaboration is part of a six-year plan Nissan calls "Power 88"; other technology projects include smart cruise control, distance control assist, and moving object detection--basically, more and more ways of automating the driving experience.

All of which raises the question: won't mind-reading cars be obsolete in an era of driverless cars (second video)?

Source: Technology Review

Thursday, 29 September 2011

Engineers “Cook” Promising New Heat-Harvesting Nanomaterials in Microwave Oven

Sept 29, 2011

Engineering researchers have developed new thermoelectric nanomaterials, pictured above, that could lead to techniques for better capturing and putting this waste heat to work. The key ingredients for making marble-sized pellets of the new material are aluminum and a common, everyday microwave oven.

Waste heat is a byproduct of nearly all electrical devices and industrial processes, from driving a car to flying an aircraft or operating a power plant. Engineering researchers at Rensselaer Polytechnic Institute have developed new nanomaterials that could lead to techniques for better capturing and putting this waste heat to work. The key ingredients for making marble-sized pellets of the new material are aluminum and a common, everyday microwave oven.

Harvesting electricity from waste heat requires a material that is good at conducting electricity but poor at conducting heat. One of the most promising candidates for this job is zinc oxide, a nontoxic, inexpensive material with a high melting point. While nanoengineering techniques exist for boosting the electrical conductivity of zinc oxide, the material’s high thermal conductivity is a roadblock to its effectiveness in collecting and converting waste heat. Because thermal and electrical conductivity are related properties, it’s very difficult to decrease one without also diminishing the other.

However, a team of researchers led by Ganpati Ramanath, professor in the Materials Science and Engineering Department at Rensselaer, in collaboration with the University of Wollongong, Australia, have demonstrated a new way to decrease zinc oxide’s thermal conductivity without reducing its electrical conductivity. The innovation involves adding minute amounts of aluminum to zinc oxide, and processing the materials in a microwave oven. The process is adapted from a technique invented at Rensselaer by Ramanath, graduate student Rutvik Mehta, and Theo Borca-Tasciuc, associate professor in the Department of Mechanical, Aerospace, and Nuclear Engineering (MANE). This work could open the door to new technologies for harvesting waste heat and creating highly energy efficient cars, aircraft, power plants, and other systems.

“Harvesting waste heat is a very attractive proposition, since we can convert the heat into electricity and use it to power devices — like in a car or a jet — that is creating the heat in the first place. This would lead to greater efficiency in nearly everything we do and, ultimately, reduce our dependence on fossil fuels,” Ramanath said. “We are the first to demonstrate such favorable thermoelectric properties in bulk-sized high-temperature materials, and we feel that our discovery will pave the way to new power harvesting devices from waste heat.”

Results of the study are detailed in the paper “Al-Doped Zinc Oxide Nanocomposites with Enhanced Thermoelectric Properties,” published recently by the journal Nano Letters.

To create the new nanomaterial, researchers added minute quantities of aluminum to shape-controlled zinc oxide nanocrystals, and heated them in a $40 microwave oven. Ramanath’s team is able to produce several grams of the nanomaterial in a matter of few minutes, which is enough to make a device measuring a few centimeters long. The process is less expensive and more scalable than conventional methods and is environmentally friendly, Ramanath said. Unlike many nanomaterials that are fabricated directly onto a substrate or surface, this new microwave method can produce pellets of nanomaterials that can be applied to different surfaces. These attributes, together with low thermal conductivity and high electrical conductivity, are highly suitable for heat harvesting applications.

“Our discovery could be key to overcoming major fundamental challenges related to working with thermoelectric materials,” said project collaborator Borca-Tasciuc. “Moreover, our process is amenable to scaling for large-scale production. It’s really amazing that a few atoms of aluminum can conspire to give us thermoelectric properties we’re interested in.”

Source: Rensselaer Polytechnic Institute

Silicon Ink Is Spot On, NREL Experiments Show

National Renewable Energy Laboratory (NREL)
Sept 29, 2011

Ink can cause a mess, but the Silicon Ink developed by Innovalight behaves itself so well that when it is added to a solar cell it doesn't clump or spill, instead it boosts the cell's power by a startling, profit-boosting 5 to 7 percent.

Both solar cells and T-shirts can be enhanced with a screen printer, some ink and a squeegee.

But it takes a real special ink to suspend silicon nanoparticles so uniformly that it can lay down the precise microns-thick lines needed to dope the silicon emitter exactly under the front metal contacts. Those contacts make a solar cell work.

Innovalight, a small start-up from Sunnyvale, Calif., came up with an ingenious way to suspend silicon in a solution without the tiny particles glomming onto one another or sinking to the bottom of the container.

But could that Silicon Ink prove useful for solar cells?

Researchers at the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) proved that the answer is "yes." And the winners could be the solar cell industry and the environment, because Silicon Ink, when added to the manufacturing process, can make solar cells more efficient and save a large plant hundreds of millions of dollars each year.

NREL and Innovalight shared a coveted R&D 100 award for 2011 for the Silicon Ink technology. Given by R&D 100 Magazine, the R&D 100 awards are referred to in the industry as the "Oscars of Invention." Silicon Ink's ability to boost efficiency in such a low-cost way prompts some in the industry to label it "liquid gold."

Impurities in Silicon Are Key to Making Contacts, Making Electricity

Silicon is the key ingredient in most of the billions of solar cells made each year worldwide.

Dopants or impurities are used to change the conductivity of silicon and to create the internal electric fields that are needed to turn photons into electrons and thus into electricity. One of the great challenges is to distribute the exact concentrations of dopants in precisely the correct locations throughout the device.

Innovalight scored big with Silicon Ink because it found a way to suspend silicon nanoparticles evenly in a solution. Those silicon nanoparticles contain dopant atoms that can be driven into silicon solar cell to form a selective emitter.

What Innovalight's potential customers and investors wanted to know was whether the ink can deliver high concentrations of dopants to extremely localized regions of the emitter and increase a solar cell's efficiency.

NREL Senior Scientists Kirstin Alberi and David Young listened to what Innovalight wanted to prove and then suggested some experiments that could help them prove it.

"The question was, 'can you print this ink in very well defined lines and drive in dopants only in the material underneath the lines to create a well-defined selective emitter," said Alberi, who began at NREL three years ago as a post-doctorate researcher. If so, the increased concentration of dopants right under the contacts would lower the resistance at the metal contact, while the rest of the cell contained low-doped silicon — and that would mean jumps in efficiency and savings of huge amounts of money.

"On some level, you want the emitter to be highly doped so it makes a better contact with the metal," Alberi said. "But if it's too heavily doped elsewhere, that's bad."

That's why a "selective emitter" that is heavily doped only in precise portions of a solar cell is such a promising technology.
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New technology uses solar UV to disinfect drinking water

Sept 29, 2011
Civil engineering professor Ernest "Chip" R. Blatchley III inspects a parabolic reflector for a prototype water-disinfection system he built as part of an effort to help provide safe drinking water to a large segment of the world's population in developing nations. The system uses ultraviolet radiation from the sun to kill waterborne pathogens. Sunlight is captured by the reflector and focused onto a UV-transparent pipe though which water flows continuously. (Purdue University photo/Andrew Hancock)

A team of Purdue University researchers has invented a prototype water-disinfection system that could help the world's 800 million people who lack safe drinking water.

The system uses the sun's ultraviolet radiation to inactivate waterborne pathogens. Sunlight is captured by a parabolic reflector and focused onto a UV-transparent pipe though which water flows continuously.

"We've been working on UV disinfection for about 20 years," said Ernest "Chip" R. Blatchley III, a professor of civil engineering. "All of our work up until a couple years ago dealt with UV systems based on an artificial UV source. What we are working on more recently is using ultraviolet radiation from the sun."

Motivating the research is the need to develop practical, inexpensive water-treatment technologies for a large segment of the world's population in developing nations.

"More than 800 million people lack access to what we consider to be 'improved' water," Blatchley said. "The water available for people to drink in many developing countries hasn't been treated to remove contaminants, including pathogenic microorganisms. As a result, thousands of children die daily from diarrhea and its consequences, including dehydration. Half of the world's hospital beds are occupied by people who are sickened by the water they drink."

Blatchley built the parabolic reflector in his garage. The team, including an undergraduate student supported by a National Science Foundation program, finished the prototype in the lab, lining it with aluminum foil. The system was then tested on the roof of Purdue's Civil Engineering Building.

"It turns out that the solar radiation we receive in Indiana at some times of year is intense enough to inactivate some waterborne microorganisms with this type of system," he said. "We demonstrated that we can disinfect water using sunlight. The reactor was very inexpensive to build, less than $100 for the materials."

The natural UV system inactivated E. coli bacteria. However, the system must be able to kill dangerous pathogens such as Vibrio cholerae, which causes cholera, and Salmonella typhi, which causes typhoid, and Cryptosporidium parvum, which causes cryptosporidiosis, a parasitic disease that causes diarrhea.

"In the future we want to prove that our solar-UV system is going work against these other pathogens," said Blatchley, who has worked on the project with doctoral student Eric Gentil Mbonimpa, who is from Rwanda, and Bryan Vadheim, an undergraduate from Montana State University. "We also want to automate it and build sensors for it so that we know how fast the water should be pumped through the system, depending on how sunny it is at any particular time."

The NSF funded Vadheim's work through its Research Experiences for Undergraduates program.

The parabolic reflector is made out of a wood called paulownia.

"That material was selected because the tree grows very rapidly in regions near the equator, where many people lack safe drinking water," Blatchley said. "It is very light, strong and stable, so it's not going to twist or warp or bend or crack in a climate that's alternating between humid and dry."

Natural UV has a longer wavelength than most artificial UV sources, which means it has less energy. Blatchley's hypothesis, however, is that UV from sunlight will inactivate pathogens via the same mechanism as artificial UV: The radiation damages the genetic material of microbes, preventing them from reproducing.

"We are looking at other inexpensive reflecting materials, for example metalized plastic," Blatchley said. "It's similar to the material that's used to make potato chip bags. We've done measurements, and some of these materials are about twice as reflective as aluminum foil."

Improving water quality in developing countries is one of 14 "grand challenges" established by the National Academy of Engineering and also has been named a "millennium development goal" by the United Nations.

Blatchley also is working on an inexpensive filtration system that uses layers of sand and gravel to clean water. The filters were developed by Aqua Clara International, a Michigan-based non-profit corporation. Purdue and Aqua Clara are teaming up with Moi University in Kenya on that project. Purdue students tested the behavior of the filters in a Global Design Team project in Africa through Purdue's Global Engineering Program.

Water flows slowly through the filter, allowing a bacterial film to establish near the top of the filter to remove organic contaminants while certain pathogens also are removed by attachment to the sand.

However, the water may still require disinfection to kill remaining pathogens, and it might be possible to use the slow-sand filters in combination with a water-disinfection system like the new solar UV approach.

"We want to develop drinking water treatment systems that improve water quality for people in developing countries, using Kenya as an example," Blatchley said.

Aqua Clara has developed a business model for the filtration system.

"This provides business opportunities for local entrepreneurs who are trained how to make these filters out of locally available materials," he said. "You can build one of these things for $10, and it's capable of producing something like 40 liters of water a day. It's intended to produce enough water for a family of four."

The use of the filters is becoming more widespread.

"About 1,900 of the sand filters have been installed in villages throughout Kenya," said William Anderson, director of the Global Engineering Program. "More and more, Purdue's faculty and students are extending our land-grant tradition for the benefit of people throughout the world."

Source: Purdue University

New Battery Could Be Just What the Grid Ordered

Technology Review
Sept 29, 2011

Utilities need cheap, long-lasting ways to store the excess energy produced by power plants, especially as intermittent power from solar and wind farms is added to the mix. Unfortunately, the batteries available for grid-level storage are either too expensive or don't last for the thousands of cycles needed to make them cost-effective.

A new battery developed by Aquion Energy in Pittsburgh uses simple chemistry—a water-based electrolyte and abundant materials such as sodium and manganese—and is expected to cost $300 for a kilowatt-hour of storage capacity, less than a third of what it would cost to use lithium-ion batteries. Third-party tests have shown that Aquion's battery can last for over 5,000 charge-discharge cycles and has an efficiency of over 85 percent.

The company has now received $30 million in venture capital to step up manufacturing of its sodium-ion batteries. The new technology could be the cheapest way to store large amounts of energy for the power grid using batteries, says Jay Whitacre, the company's founder and chief technology officer.

Aquion's battery uses an activated carbon anode and a sodium- and manganese-based cathode. A water-based electrolyte carries sodium ions between the two electrodes while charging and discharging. The principle is similar to lithium-ion, but sodium ions are more abundant and hence cheaper to use. Compared to solvent-based electrolytes, the aqueous electrolyte is also easier to work with and cheaper. Even better, the materials are nontoxic and the battery is 100 percent recyclable, Whitacre says.

Grid-scale trials of the technology are next. Aquion has started shipping pre-production battery prototypes to off-grid solar power companies. Next month, a 1,000-volt module will go to KEMA, a Dutch energy consulting and testing outfit, which has a facility outside Philadelphia.

Utilities use stored energy to meet electrical demand during peak usage periods, a practice called peak shaving, which helps keep the grid reliable and efficient and electricity prices low. Whitacre says Aquion's battery is designed for these grid applications. "It's very well-suited for off-grid solar and wind support, and also for peak shaving," he says. "It's two very different applications, and our battery has been shown to be effective in both."
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Analysis says electric vehicles sales not affected by incentives

Sept 29, 2011

A study by JATO Dynamics suggests government incentives are having little impact on the sales of electric vehicles.

According to JATO, demand for electric vehicles (EV) increased ten-fold to 5,220 across Europe in the first half of this year compared to the 500 registered in the same period last year.

Germany, where incentives amount to around €380 (£330) per vehicle, is the leading EV market with January–June registrations of around 1,000. Denmark has incentives which amount to some €20,600 over five years of ownership but registered fewer than 300 EVs in the same period.

Where incentives are similar — such as Spain and the UK at around €6,500 per vehicle — there is a wide gap between registrations. The UK registered 599 EVs and Spain 122.

Gareth Hession, JATO’s vice-president for research, said: ‘The discrepancies highlight the apparently low influence of price on purchase decisions across the region.

‘Given this, it’s reasonable to conclude that sales are more affected by other factors such as the degree of urban geography, market maturity and charging infrastructure than was previously thought.’

Other factors that JATO believes influences EV ownership are the rights to use bus lanes and free city centre parking, such as in Oslo, and exemption from congestion charges as in London.

Europe’s biggest EV markets in the first half of this year after Germany were France (950 units), Norway (850), the UK (600), Austria (350) and Denmark (280). Spain (120) and Italy (100) were at the bottom of the table.

In a statement Hession said the EV market is set for significant growth, adding: ‘As the market matures we might expect subsidies to exert greater influence as other considerations such as charging infrastructure are addressed.

‘As it stands today, even the large subsidies don’t address the majority of end user concerns around real world application, flexibility and fitness for purpose.

‘It will be critical for manufacturers to better understand the factors if they are to maximise customer engagement and sales growth.’

Source: The Engineer

Additional Information:

Laser polishes components to a high-gloss finish

Sept 29, 2011

At present, components used in areas such as tool and die making generally have to be painstakingly polished by hand – but a recently developed automated process could soon offer a much faster solution. From November 29 to December 2 at the 2011 EuroMold exhibition in Frankfurt, Fraunhofer researchers will be presenting a machine tool that uses laser polishing to give even complex 3D surfaces a high-gloss finish.

Millimeter by millimeter, the polisher uses grinding stones and polishing pastes to polish the surface of a metal mold, working at a rate of some ten minutes per square centimeter. This activity is time-consuming and hence incurs a significant cost. What is more, many companies are struggling to find new recruits for such a challenging yet monotonous task.

But the era of laborious hand polishing could soon be over: In collaboration with the companies Maschinenfabrik Arnold and S&F Systemtechnik, researchers at the Fraunhofer Institute for Laser Technology ILT have developed a novel type of machine tool which can polish both simple and complex surfaces using laser beams. "Conventional methods remove material from the surface to even it out. Our method is different: It uses a laser to melt a thin surface layer roughly 20 to 100 µm deep," says Dr.-Ing. Edgar Willenborg, Section Head at the ILT in Aachen. "Surface tension – a property that applies to all liquids – ensures that the layer of liquid metal solidifies evenly."

Depending on the material, the project team can already produce surfaces with an average roughness (Ra) of between 0.1 and 0.4 µm. "Hand polishing can still get better results than that," Willenborg admits, "but the point is that in many applications – for example molds for glass-making, forming and forging tools – a medium-quality surface is all that is needed". The new machine developed at the Aachen-based ILT has the potential to save considerable amounts of time and money in these areas:
The machine polishes surfaces up to ten times faster than a hand polisher and is an excellent option for serial production and for polishing small batches.

The new laser polishing system consists of a 5-axis gantry system plus an additional 3-axis laser scanner, a design that enables the workpiece to be accessed from all sides. Carefully arranged mirrors deflect the laser beam to allow feed rates (the speed at which the laser beam moves along the workpiece within a specified time frame) in excess of one meter a second, even on small surfaces. An end-to-end CAM NC data chain has also been developed which draws on a 3D CAD model of the component to be polished. The beam path data is calculated on the basis of this model. "For this step, we use conventional computer-aided manufacturing (CAM) programs such as those used in milling processes. The advantage is that companies are typically already running those kinds of programs so the employees know how to use them," says Willenborg. The calculated beam path data is then supplied to a special post-processing software program developed at the ILT. This program configures more advanced aspects – for example adapting the laser to the specific angle of incidence and component edges in each particular case.

This new process technology also offers benefits in terms of machine development: "The fact that we are working with a completely new operating principle makes it much easier to construct the machines we need," Willenborg says. "Unlike conventional polishing techniques, laser polishing does not primarily rely on the rigidity of the machine to achieve high component quality, but rather on the physics of surface tension."

The laser polishing machine will soon be ready for market launch. This year‘s EuroMold fair is the first time the researchers have presented their new development to the public.

Source: Fraunhofer-Gesellschaft

Carbon Nanotubes to Make Solar Cells Affordable, Flexible

Sept 29, 2011

      Mark C. Hersam                          Tobin J. Marks

Researchers from Northwestern University have developed a carbon-based material that could revolutionize the way solar power is harvested. The new solar cell material – a transparent conductor made of carbon nanotubes – provides an alternative to current technology, which is mechanically brittle and reliant on a relatively rare mineral.

Due to Earth's abundance of carbon, carbon nanotubes have the potential to boost the long-term viability of solar power by providing a cost-efficient option as demand for the technology increases. In addition, the material’s mechanical flexibility could allow solar cells to be integrated into fabrics and clothing, enabling portable energy supplies that could impact everything from personal electronics to military operations.

The research, headed by Mark C. Hersam, professor of materials science and engineering and professor of chemistry, and Tobin J. Marks, Vladimir N. Ipatieff Professor of Catalytic Chemistry and professor of materials science and engineering, is featured on the cover of the October 2011 issue of Advanced Energy Materials, a new journal that specializes in science about materials used in energy applications.

Solar cells are comprised of several layers, including a transparent conductor layer that allows light to pass into the cell and electricity to pass out; for both of these actions to occur, the conductor must be both electrically conductive and also optically transparent. Few materials concurrently possess both of these properties.

Currently, indium tin oxide is the dominant material used in transparent conductor applications, but the material has two potential limitations. Indium tin oxide is mechanically brittle, which precludes its use in applications that require mechanical flexibility. In addition, indium tin oxide relies on the relatively rare element indium, so the projected increased demand for solar cells could push the price of indium to problematically high levels.

“If solar technology really becomes widespread, as everyone hopes it will, we will likely have a crisis in the supply of indium,” Hersam said. “There’s a great desire to identify materials – especially earth-abundant elements like carbon – that can take indium’s place in solar technology.”

Hersam and Marks’ team has created an alternative to indium tin oxide using single-walled carbon nanotubes, tiny, hollow cylinders of carbon just one nanometer in diameter.

The researchers have gone further to determine the type of nanotube that is most effective in transparent conductors. Nanotubes’ properties vary depending on their diameter and their chiral angle, the angle that describes the arrangement of carbon atoms along the length of the nanotube. These properties determine two types of nanotubes: metallic and semiconducting.

Metallic nanotubes, the researchers found, are 50 times more effective than semiconducting ones when used as transparent conductors in organic solar cells.

“We have now identified precisely the type of carbon nanotube that should be used in this application,” Hersam said.

Because carbon nanotubes are flexible, as opposed to the brittle indium tin oxide, the researchers’ findings could pave the way for many new applications in solar cells. For example, the military could incorporate the flexible solar cells into tent material to provide solar power directly to soldiers in the field, or the cells could be integrated into clothing, backpacks, or purses for wearable electronics.

“With this mechanically flexible technology, it’s much easier to imagine integrating solar technology into everyday life, rather than carrying around a large, inflexible solar cell,” Hersam said.

Researchers are now examining other layers of the solar cell to explore also replacing these with carbon-based nanomaterials.

Source: Northwestern University

Nanostructure-Based Process Will Streamline Production of Magnetic Materials

Sept 29, 2011

Scientists at the University of Massachusetts Amherst report that for the first time they have designed a much simpler method of preparing ordered magnetic materials than ever before, by coupling magnetic properties to nanostructure formation at low temperatures.

The innovative process allows them to create room-temperature ferromagnetic materials that are stable for long periods more effectively and with fewer steps than more complicated existing methods. The approach is outlined by UMass Amherst polymer scientist Gregory Tew and colleagues in the Sept. 27 issue of Nature Communications.

Tew explains that his group’s signature improvement is a one-step method to generate ordered magnetic materials based on cobalt nanostructures by encoding a block copolymer with the appropriate chemical information to self-organize into nanoscopic domains. Block copolymers are made up of two or more single-polymer subunits linked by covalent chemical bonds.

The new process delivers magnetic properties to materials upon heating the sample once to a relatively low temperature, about 390 degrees (200 degrees Celsius), which transforms them into room-temperature, fully magnetic materials. Most previous processes required either much higher temperatures or more process steps to achieve the same result, which increases costs, Tew says.

He adds, "The small cobalt particles should not be magnetic at room temperature because they are too small. However, the block copolymer’s nanostructure confines them locally which apparently induces stronger magnetic interactions among the particles, yielding room-temperature ferromagnetic materials that have many practical applications."

"Until now, it has not been possible to produce ordered, magnetic materials via block copolymers in a simple process," Tew says. "Current methods require multiple steps just to generate the ordered magnetic materials. They also have limited effectiveness because they may not retain the fidelity of the ordered block copolymer, they can’t confine the magnetic materials to one domain of the block copolymer, or they just don’t produce strongly magnetic materials. Our process answers all these limitations."

Magnetic materials are used in everything from memory storage devices in our phones and computers to the data strips on debit and credit cards. Tew and colleagues have discovered a way to build block copolymers with the necessary chemical information to self-organize into nanoscopic structures one millionth of a millimeter thin, or about 50,000 times thinner than the average human hair.

Earlier studies have demonstrated that block copolymers can be organized over relatively large areas. What makes the UMass Amherst research group’s results so intriguing, Tew says, is the possible coupling of long-range organization with improved magnetic properties. This could translate into lower-cost development of new memory media, giant magneto-resistive devices and futuristic spintronic devices that might include "instant on" computers or computers that require much less power, he points out.

He adds, "Although work remains to be done before new data storage applications are enabled, for example making the magnets harder, our process is highly tunable and therefore amendable to incorporating different types of metal precursors. This result should be interesting to every scientist in nanotechnology because it shows conclusively that nano-confinement leds to completely new properties, in this case room temperature magnetic materials."

"Our work highlights the importance of learning how to control a material’s nanostructure. We show that the nanostructure is directly related to an important and practical outcome, that is, the ability to generate room-temperature magnets."

"Our work highlights the importance of learning how to control a material’s nanostructure. We show that the nanostructure is directly related to an important and practical outcome, that is, the ability to generate room temperature magnets." As part of this study, the UMass Amherst team also demonstrated that using a block copolymer or nanoscopic material results in a material that is magnetic at room temperature. By contrast, using a homopolymer, or unstructured material, leads only to far less useful non- or partial-magnetic materials.

Source: University of Massachusetts Amherst

Scientists Identify New Microbe-Produced Advanced Biofuel as an Alternative to Diesel Fuel

Lawrence Berkeley National Laboratory (Berkeley Lab)
Sept 29, 2011

Researchers with the U.S Department of Energy (DOE)’s Joint BioEnergy Institute (JBEI) have identified a potential new advanced biofuel that could replace today’s standard fuel for diesel engines but would be clean, green, renewable and produced in the United States. Using the tools of synthetic biology, a JBEI research team engineered strains of two microbes, a bacteria and a yeast, to produce a precursor to bisabolane, a member of the terpene class of chemical compounds that are found in plants and used in fragrances and flavorings. Preliminary tests by the team showed that bisabolane’s properties make it a promising biosynthetic alternative to Number 2 (D2) diesel fuel.

“This is the first report of bisabolane as a biosynthetic alternative to D2 diesel, and the first microbial overproduction of bisabolene in Escherichia coli and Saccharomyces cerevisiae,” says Taek Soon Lee, who directs JBEI’s metabolic engineering program and is a project scientist with Lawrence Berkeley National Laboratory (Berkeley Lab)’s Physical Biosciences Division. “This work is also a proof-of-principle for advanced biofuels research in that we’ve shown that we can design a biofuel target, evaluate this fuel target, and produce the fuel with microbes that we’ve engineered.”

Lee is the corresponding author of a paper reporting this research in the journal Nature Communications entitled “Identification and microbial production of a terpene-based advanced biofuel.” Pamela Peralta-Yahya is the lead author of this paper. Other co-authors are Mario Ouellet, Rossana Chan, Aindrila Mukhopadhyay and Jay Keasling

The rising costs and growing dependence upon foreign sources of petroleum-based fuels, coupled with scientific fears over how the burning of these fuels impacts global climate, are driving the search for carbon-neutral renewable alternatives. Advanced biofuels – liquid transportation fuels derived from the cellulosic biomass of perennial grasses and other non-food plants, as well as from agricultural waste – are highly touted for their potential to replace gasoline, diesel and jet fuels. Unlike ethanol, which can only be used in limited amounts in gasoline engines and can’t be used at all in diesel or jet engines, plus would corrode existing oil pipelines and tanks, advanced biofuels are drop-in fuels compatible with today’s engines, and delivery and storage infrastructures.

“We desperately need drop-in, renewable biofuels that can directly replace petroleum-derived fuels, particularly for vehicles that cannot be electrified,” says co-author Keasling, CEO of JBEI and a leading authority on advanced biofuels. “The technology we describe in our Nature Communications paper is a significant advance in that direction.”
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Tuesday, 27 September 2011

Carnegie Mellon Study Finds Benefits of Plug-in Vehicles Depend on Battery Size

Sept 27, 2011

Thinking about buying a new plug-in vehicle? You may want to check the size of its battery first.

Carnegie Mellon University's Jeremy J. Michalek and co-authors report that plug-in vehicles with small battery packs and hybrid electric vehicles (HEVs) that don't plug in can reduce life cycle impacts from air emissions and enhance oil security at low or no additional cost over a lifetime. But plug-in vehicles with large battery packs are more costly and may have higher or lower emissions than HEVs depending on where and when they are plugged in.

In a study appearing this week in the Proceedings of the National Academy of Sciences, Michalek argues that electrified vehicles with smaller battery packs are more efficient in reducing societal costs for health care, environmental damages and oil consumption.

"Current government policy provides larger subsidies for vehicles with larger battery packs, assuming that larger is better," said Michalek, an associate professor of engineering and public policy and mechanical engineering at CMU. "While larger battery packs allow plug-in vehicles to drive longer distances on electric power instead of gasoline, they are also expensive and heavy, they are underutilized when the battery capacity is larger than needed for a typical trip, they require more charging infrastructure and they produce more emissions during manufacturing."

U.S. policy has been pushing the auto industry to investigate alternatives to fossil fuels. The American Recovery and Reinvestment Act of 2009 provides up to $7,500 in tax credits for up to 200,000 plug-in vehicles.

"Because vehicles with larger battery packs are more expensive, fewer of them can be subsidized, and that can result in lower total benefits," said Michalek, who recently received a $400,000 grant from the National Science Foundation (NSF) to analyze how public policy could help determine the types of vehicles built in coming years and how consumers might respond to these vehicles.

"It's possible that in the future plug-in vehicles with large battery packs might offer the largest benefits at competitive costs if the right factors fall into place, including sufficiently low cost batteries, high gasoline prices, low emission electricity and long battery life," said study co-author Mikhail Chester, assistant professor of sustainable engineering at Arizona State University. "But such a future is not certain, and in the near term, HEVs and plug-in vehicles with small battery packs provide more emissions benefits and oil displacement benefits per dollar spent."

"With increasing energy and environmental constraints, transitioning from conventional gasoline vehicles to hybrid and plug-in vehicles offers an opportunity for improving energy independence and air quality while helping to address global warming," said study co-author Constantine Samaras, an engineer at the RAND Corporation.

Michalek's research is aimed at understanding tradeoffs in the capabilities of new technologies and to predict what near- and long-term strategies should be. "Given the major spending cuts under debate in Washington, it is important that we get the most benefits out of spending designed to improve the environment and energy security," Michalek said. "In the near term, HEVs and plug-in vehicles with small battery packs offer more cost-effective benefits. More research on batteries — especially lowering cost — and a transition to a cleaner electricity grid are needed to pursue a future where large battery packs may also be able to help address climate change, air pollution and oil dependency at competitive costs."

Source: Carnegie Mellon University

New solar cell technology gives light waves “amnesia”

Sept 27, 2011

For years, scientists have dealt with the problem of trying to increase the efficiency and drive down the cost of solar cells. Now researchers have hit upon a new idea—trying to give the light collected by solar cells a bit of “amnesia.”

At the U.S. Department of Energy's (DOE) Argonne National Laboratory, nanoscientists Chris Giebink and Gary Wiederrecht, collaborating with Northwestern University Professor Michael Wasielewski, have investigated the use of fluorescent plastics called luminescent solar concentrators (LSCs) that can be used to lower the cost of electricity from solar cells.

“In order to make solar power competitive in energy markets, we either need to get more energy from the cells we've already developed or find ways to make cheaper cells that give us the same amount of energy,” Giebink said.

The three researchers are part of the Argonne-Northwestern Solar Energy Research Center, one of 46 Energy Frontier Research Centers established in 2009 and supported by DOE's Office of Science.

Concentrating sunlight is one strategy to squeeze more power out of existing solar cells, which ultimately reduces the cost of the energy they produce. The question occupying researchers today is how best to gather as much sunlight as cheaply as possible. Although lenses and mirrors are one solution—think burning a piece of paper with a magnifying glass on a sunny day—they must be continually aimed at the sun as it moves across the sky each day, which requires an expensive tracking system.

Luminescent solar concentrators are an inexpensive, alternative approach that do not require solar tracking because they capture sunlight and change it to a different wavelength, according to Giebink. “We're actively shifting the frequency of the light by absorbing and re-emitting it,” he said. “LSCs act kind of like flat funnels—we try to absorb a lot of light over the face of a plastic slab filled with dye, and then re-direct it all back out the edges. The whole process is designed to intensify the light as much as possible.”

The theoretical potential for this intensification, Giebink said, can exceed the equivalent of one hundred “suns”—the measurement of solar radiation on one spot. However, actual implementation has until now failed to produce such high intensities. “The main problem we're running into is that light is getting lost in the slabs either due to reabsorption or to scattering, and that's the problem we have to solve,” he said.

Using instrumentation and equipment at Argonne's Center for Nanoscale Materials, the researchers focused on altering the way light is re-emitted and reabsorbed inside an LSC by taking advantage of optical ‘microcavity' effects, which occur when the dimensions of a structure are similar to the wavelength of light. In this case, the scientists were able to use a series of thin films with nanometer-scale changes in thickness to produce a ‘resonance-shifting' effect, in which light fails to “recognize” the environment that it is emitted from, drastically reducing reabsorption. “It really is like giving light amnesia—if light forgets how it came in, it's less likely to get reabsorbed or scattered out,” Wiederrecht said.

Although the Argonne experimental research explored how LSCs work only in one dimension, both Giebink and Wiederrecht believe that a two-dimensional LSC analysis would show even greater efficacy for resonance-shifting. “By finding better and better ways to pull this kind of switcheroo, the higher the efficiency we're going to get,” Giebink said. “We've demonstrated the general principle, now we just have to find the best pattern of dye thicknesses or alternatively the best way to vary the thickness of the glass.”

Source: Argonne National Laboratory

Project succeeds in developing electric car battery with greater range

Sept 27, 2011

A project led by advanced battery manufacturer Axeon and co-funded by the Technology Strategy Board has been successful in developing a new battery for use in electric cars that offers over a 35% improvement in range compared to existing technologies, for the same weight.

In 2009, the Technology Strategy Board awarded over £680k of funding to the consortium led by Axeon (bringing the total project funding to over £1.3m), with the aim of developing an innovative high energy density battery system for an emission-free electric vehicle.

The battery uses Nickel Cobalt Manganese (NCM) electrochemistry which theoretically requires 50% less volume and 30% less mass when compared to Lithium Iron Phosphate chemistry (at cell level)

A key goal of the project was to confirm that these cell level benefits pass through to the battery pack level when taking into account overall packaging, cell retention, cooling and interconnects, Battery Management System (BMS) components and overall system functionality.

The project included subjecting the battery to automotive environmental validation testing and the learning from this has been incorporated into the final design to ensure a robust solution.

Axeon and its partners, Ricardo and Allied Vehicles, have now delivered an advanced demonstrator that has been deployed into a test vehicle, increasing its range, functionality and performance. The project has confirmed that it is feasible to replace Lithium Iron Phosphate technology with NCM and that the majority of cell level benefits migrate to battery pack level.

The demonstrator pack uses NCM “pouch” cells (a relatively new technology for electric vehicles) that have been innovatively packaged in modular building blocks which additionally support a range of thermal mamagement options and additionally allow Axeon to support rapid prototyping into a range of other vehicle types with significantly reduced development lead times.

Added benefits of the new system, which was tested on a vehicle platform from Allied Vehicles, include increased ground clearance, better driver experience due to improved weight distribution and more power giving better drivability.

The new battery also integrates an automotive BMS developed by Ricardo. This works with multiple cell chemistries, has active balancing and delivers diagnostic and prognostic information to the vehicle control system.

The partners are now in active discussions on commercialisation of the new technologies.

Source: Axeon

Building innovation in India

MIT News
Sept 26, 2011

Despite a global economic downturn that has rippled across India, the country remains one of the world’s fastest growing economies, second only to China. India is also the planet’s second most populous nation, expected to overtake China by 2030.

In the first ever MIT-India Conference, held Friday, Sept. 23, at the MIT Media Lab, speakers from both MIT and India explored the challenges associated with India’s rapid expansion, including energy distribution, rural access to health care, and efforts to curb governmental corruption. One theme was prevalent throughout: India’s many hurdles also provide unprecedented opportunity for innovation.

N.R. Narayana Murthy, the conference’s keynote speaker and founder and chairman emeritus of Infosys Limited, said the time is right for those who choose to work in India.

“They can be part of an era where there’s so much confidence, there is so much hope, there is so much ambition,” Murthy said. “And there is so much that needs to be done.”

The conference featured entrepreneurs, venture capitalists, finance experts and government officials from India, as well as MIT faculty working on India-related projects. The one-day event sought to strengthen the relationship between MIT and India, which MIT Chancellor Eric L. Grimson characterized at the event as a “century-long friendship.”

In his opening remarks, Grimson noted that the friendship began in 1906 when Ishwar Das Varshnei became the first Indian to graduate from MIT. In 2010, his great-grandsons, twins Kush and Lav, followed in his footsteps, earning PhDs in electrical engineering and computer science. Today, more than 270 students of Indian descent attend MIT; Grimson cited the Institute’s many India-related projects — fifteen of which were featured in a Technology Showcase during the conference — as a strong bridge between the Institute and India.

“If MIT wants to stay on the forefront of technology, it has to maintain ties with India,” Grimson said.

The conference got underway with a panel discussion on energy and the environment. Panelists noted that as India’s population continues to expand, so too will its energy demands.

E.A.S. Sarma, former secretary of economic affairs in India, cautioned that the country “can’t go in a wanton manner for megawatts.” Sarma, now a social activist working to protect rural communities from pollution created by local powerplants, insists that communities should have a say when it comes to building new plants.

“If you bring people into discussions from the start, they may help develop benign processes,” Sarma said.

However, Robert Stoner, associate director of the MIT Energy Initiative, pointed out that above and beyond meeting the energy needs of India’s projected population growth, nearly 400 million current citizens already lack access to electricity.

While panelists discussed the potential contributions of solar, natural gas and nuclear energy, the overall consensus was that it would take a combination of approaches to solve India’s energy problem. And in many cases, those solutions will have to be extremely affordable.

“There’s opportunity for low-cost innovation in lots of areas,” Stoner said.
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Copper nanowires could lower touch screen, LED and solar cell costs

Sept 27, 2011

Copper nanowires may be coming to a little screen near you.

These new nanostructures have the potential to drive down the costs of displaying information on cell phones, e-readers and iPads, and they could also help engineers build foldable electronics and improved solar cells, according to new research.

Duke chemist Ben Wiley and his graduate student have developed a technique to organize copper atoms in water to form long, thin, non-clumped nanowires. The nanowires are then transformed into transparent, conductive films and coated onto glass or plastic.

The new research shows that the copper nanowire films have the same properties as those currently used in electronic devices and solar cells, but are less expensive to manufacture. The results were published online Sept. 23 in Advanced Materials.

The films that currently connect pixels in electronic screens are made of indium tin oxide, or ITO. It is highly transparent, which transmits the information well. But the ITO film must be deposited from a vapor in a process that is a thousand times slower than newspaper printing, and, once the ITO is in the device, it cracks easily. Indium is also an expensive rare earth element, costing as much as $800 per kilogram.

These problems have driven worldwide efforts to find less expensive materials that can be coated or printed like ink at much faster speeds to make low-cost, transparent conducting films, Wiley said.

One alternative to an ITO film is to use inks containing silver nanowires. The first cell phone with a screen made from silver nanowires will be on the market this year. But silver, like indium, is still relatively expensive at $1400 per kilogram.

Copper, on the other hand, is a thousand times more abundant than indium or silver, and about 100 times less expensive, costing only $9 per kilogram.

In 2010, Wiley and his graduate student Aaron Rathmell showed that it was possible to form a layer of copper nanowires on glass to make a transparent conducting film.

But at that time, the performance of the film was not good enough for practical applications because the wires clumped together. The new way of growing the copper nanowires and coating them on glass surfaces eliminates the clumping problem, Wiley said.

He and Rathmell also created the new copper nanowires to maintain their conductivity and form when bent back and forth 1,000 times. In contrast, ITO films' conduction and structure break after a few bends.

Wiley said the low-cost, high-performance, and flexibility of copper nanowires make them a natural choice for use in the next generation of displays and solar cells. He co-founded a company called NanoForge Corp in 2010 to manufacture copper nanowires for commercial applications.

In early 2011, NanoForge received a $45,000 North Carolina IDEA grant for refinement and scale-up of the manufacturing process of copper nanowires, and it is now filling orders.

With continuing development, copper nanowires could be in screens and solar cells in the next few years, which could lead to lighter and more reliable displays and also to making solar energy more competitive with fossil fuels, Wiley said.

Source: Duke University

Friday, 23 September 2011

Tests to Assess How Elevators, Fire Systems Perform in Earthquakes

Sept 23, 2011
Two graduate students look on as construction crews pour the roof slab on a five-story building at Englekirk Center. The building will be outfitted to test nonstructural components, including a working elevator, stairs, a sprinkler system and medical equipment.

Structural engineers at the UC San Diego Jacobs School of Engineering are preparing for a series of earthquake tests focused on nonstructural components, including a functioning elevator, stairs, ceilings, and passive and active fire suppression systems, such as sprinklers and partition walls, in a full-scale, five-story concrete building on the world’s largest outdoor shake table.

The tests performed at the Englekirk Structural Engineering Center at UC San Diego will be the first of their kind in the United States to focus on a broad range of systems and equipment that can malfunction during an earthquake and make it more difficult to evacuate buildings, which can lead to more injuries and deaths.

Construction crews recently completed the five-story structure with a final pouring of the roof slab. The structure is uniquely outfitted with nonstructural systems that are found in multi-use office and hospital buildings. The top two floors will feature patient beds, a patient lift, computers and other hospital equipment that are common to California medical facilities, including a complete intensive care unit and surgery suite.

“We know very little about the earthquake and post-earthquake fire performance of nonstructural systems in buildings, and even less about those in hospitals,” said Tara Hutchinson, a professor of structural engineering at the Jacobs School and principal investigator for the component of the testing program supported by the National Science Foundation. “Meanwhile, lives and property are being lost due to nonstructural damage, even under moderate seismic events.”

“While building codes in California have attempted to address this by strengthening the requirements for nonstructural components in recent years, components designed to these new requirements have not yet been tested in strong earthquakes,” Hutchinson said. “These tests will help fill this gap in knowledge,” she added.

At 25 ft. by 40 ft., the UC San Diego-Network for Earthquake Engineering Simulation Outdoor Shake Table is the largest shake table in the United States and the largest outdoor shake table in the world. The powerful hydraulic actuators at UC San Diego’s facility can simulate ground motion speeds up to six ft. per second, allowing researchers to create realistic simulations of the most devastating earthquakes on record.
Once construction crews install all non-structural components, engineers will subject the entire five-story building to large simulated earthquakes and fire tests from January through March 2012. Media will be invited to observe key tests during this time and should contact the press office at the Jacobs School of Engineering for updates as the test schedule is developed.

Source: University of California, San Diego

Simulating Turbulent Combustion Speeds Design

Oak Ridge National Laboratory
Sept 23, 2011
High-fidelity large eddy simulation (LES) of direct-injection processes in internal-combustion engines provides an essential component for development of high-efficiency, low-emissions vehicles. Here LES reveals how fuel from a state-of-the-art injector mixes with air inside an engine cylinder. Image credit: Joseph Oefelein and Daniel Strong, Sandia National Laboratories.

Air and fuel mix violently during turbulent combustion. The ferocious mixing needed to ignite fuel and sustain its burning is governed by the same fluid dynamics equations that depict smoke swirling lazily from a chimney. Large swirls spin off smaller swirls and so on. The multiple scales of swirls pose a challenge to the supercomputers that solve those equations to simulate turbulent combustion. Researchers rely on these simulations to develop clean-energy technologies for power and propulsion.

A team led by mechanical engineers Joseph Oefelein and Jacqueline Chen of Sandia National Laboratories (Sandia) simulates turbulent combustion at different scales. A burning flame can manifest chemical properties on small scales from billionths of a meter up to thousandths of a meter, whereas the motion of an engine valve can exert effects at large scales from hundredths of a meter down to millionths of a meter. This multiscale complexity is common across all combustion applications—internal combustion engines, rockets, turbines for airplanes and power plants, and industrial boilers and furnaces.

Chen and Oefelein were allocated 113 million hours on Oak Ridge Leadership Computing Facility's Jaguar supercomputer in 2008, 2009, and 2010 to simulate autoignition and injection processes with alternative fuels. For 2011 they received 60 million processor hours for high-fidelity simulations of combustion in advanced engines. Their team uses simulations to develop predictive models validated against benchmark experiments. These models are then used in engineering-grade simulations, which run on desktops and clusters to optimize designs of combustion devices using diverse fuels. Because industrial researchers must conduct thousands of calculations around a single parameter to optimize a part design, calculations need to be inexpensive.
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GE, GM in push on EV infrastructure for China

Sept 23, 2011

General Electric and General Motors Co. agreed Thursday on a pilot installation of electric vehicle charging stations in Shanghai, the latest step in the automaker's plan to develop infrastructure in China to support sales of its Chevrolet Volt electric car.

As part of the agreement, GE also agreed to buy the extended range electric cars for use at its corporate campus in Shanghai. GM plans to launch the Volt in December in China, where it has made electric vehicles a core part of its strategy for expansion despite doubts Chinese consumers will snap up such cars.

The companies gave no details about investment in the charging stations, which will include both GE's WattStations and Durastations, two different specifications for charging electric vehicles.

China is a linchpin market for GM. Earlier this week it announced plans for developing a new electric vehicle with its local partner Shanghai Automotive Industrial Corp. It also has just opened an advanced technology center to support its efforts to build more energy efficient and safer automobiles, with a lab devoted to developing new battery cells for EVs.

GE builds natural gas-fired generators for utilities, electric motors, advanced electric meters and electric car charging stations, all of which could be in higher demand if drivers buy electric cars. The company estimates the expanding market could bring it up to $500 million in revenue over the next three years.

China, the world's biggest market for new vehicles, is seen as a promising market for electric vehicles because of its keenness on limiting its dependence on costly imports of crude oil and reducing severe pollution from auto emissions.

The government has made development of so-called "new energy" vehicles a key part of its current five-year economic plan, promising subsidies and billions of dollars in new investments.

But spurring demand for electric and hybrid vehicles will hinge on providing the charging infrastructure, and bringing costs down to affordable levels, those working in the industry say.

Thursday's agreement calls for the two big U.S. companies to coordinate work with government agencies on developing EV standards.

In August, GE Energy also announced a partnership with car rental company Hertz Corp. for advancing the rollout of EVs and charging stations in China.

Source:  The Associated Press

Smarter robot arms

MIT News
Sept 21, 2011

Ask someone with her hands in her lap to pick up a coffee mug on the table she’s sitting at, and she’ll extract her hand from under the table and stretch her arm out toward the mug.

Instruct an autonomous robot to perform the same feat, and it may think for a few seconds, zigzag its robotic hand back and forth under the table, then perform what look kind of like calisthenics for a few seconds more before finally reaching for the mug.

As intuitive as it seems to a human being, spontaneously planning a trajectory around obstacles in free space is a monstrously complex computation. As a consequence, most motion-planning algorithms give up on the idea of finding the most efficient path between the robot’s initial state and its goal, settling for any path that won’t introduce collisions.

By combining two innovative algorithms developed at MIT, researchers in the Computer Science and Artificial Intelligence Laboratory (CSAIL) and the Laboratory for Information and Decision Systems (LIDS) have built a new robotic motion-planning system that calculates much more efficient trajectories through free space. This month at the Institute of Electrical and Electronics Engineers’ (IEEE) International Conference on Intelligent Robots and Systems, they’ll present a paper that describes the application of the algorithm to a robotic arm.
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Military green investments could hit $10B by 2030

Sept 23, 2011

Breakdown of the DOD's energy use for operations and facilities. Eighty-one percent of operational costs go toward jet fuel, while 64 percent of facilities costs go toward electricity.

It's no secret to anyone following green tech that the Department of Defense has taken a particular interest in advanced biofuels, vehicle fuel efficiency, renewable energy, and building efficiency. But many may not realize to what extent the DOD has changed its policy, or the large impact this shift is going to have on the economy, according to a report released yesterday afternoon by the Pew Charitable Trusts.

The report (PDF) asserts that the DOD is one of the world's largest institutional consumers of fossil fuels, consuming 300,000 barrels of oil a day in 2009. The DOD's energy cost for 2010 was $15.2 billion (PDF) with 74 percent going to operations and 26 percent going to facilities. About $11 billion of that was spent on liquid petroleum fuels, according to the report.

The study and the report, which took two years to complete, was overseen by retired Republican Senator John Warner, who is a former Chairman of the Senate Armed Services Committee, and former Secretary of the Navy. Warner is the senior policy adviser at the Pew Project on National Security, Energy, and Climate.

Aside from cost, a major nuisance of fossil fuel dependence is the danger involved in having to transport liquid fuels to combat areas, and the impact fuel availability has on the effectiveness of military operations. The DOD has estimated that 80 percent of supply convoy missions in Iraq and Afghanistan are for fuel, according to the report.

In view of that, the DOD has determined that incorporating renewables and other green tech into its energy ecosystem will improve security for the armed forces, as well as national security.

A move to less fossil fuel, especially in light of volatile oil prices, will also save the branches of the military money long-term both home and abroad, according to the report.

To that end, the DOD has set the ambitious goal of getting 25 percent of its energy needs from renewables by 2025.

The U.S. Air Force plans to be on 50 percent biofuels for all its domestic aviation needs by 2016. The U.S. Navy plans to reduce ship fuel consumption by 15 percent by 2020 compared to its 2010 levels. The U.S. Navy and the U.S. Marines both plan to get 50 percent of their needed energy from alternative energy sources by 2020.

And while all branches of the military have plans to upgrade bases and installations (PDF) with more efficiency for buildings, the U.S. Army has a "net zero" program under way to get its bases to produce as much energy and water as they consume, and reduce, recycle, and reuse their waste. Fort Bliss in Texas and Fort Carson in Colorado are on track to be net zero in all three categories by 2020.

There have also been myriad smaller rollouts and programs within the last few years.

The Navy began using algae-based shipboard fuel on a limited basis in 2010. The Army began replacing its light-use vehicles on military bases with electric vehicles and ordered military bridges made of recycled thermoplastic composite in 2009.

The Marine 3rd Battalion, 5th Marine Regiment at Forward Operating Base Jackson, and their Afghan national army counterparts have been using portable solar charges in Afghanistan that enable them to carry fewer batteries and more ammunition, solar tarps on tents to power lights, and solar panels to power mobile command centers and computers.

The report noted that the DOD's shift in energy policy is a wise choice in terms of saving money and improving its own security drastically in the coming years. But its switch is also a secondary way to protect American national security, by helping the country to become less dependent on foreign energy sources. As in other areas of tech, military investment in green technology will help it reach commercial maturity more quickly, the report said.

"In fact, the department has created a far-reaching memorandum of understanding with the Department of Energy to help accelerate the innovation process in service of the nation's energy and national security goals. DOD and DOE are working cooperatively on advanced batteries, energy efficiency, microgrids, and 'smart' technology," said the report.

Concurrent with this shift in policy, DOD clean-energy investments increased from $400 million in 2006 to $1.2 billion in 2009, a 300 percent increase. The institution plans to invest even more, projecting its green-tech investments will reach $10 billion annually by 2030.

Warner said he's not surprised that the DOD will once again be the leader in a new space as it's always been one of the earliest supporters of cutting-edge technology.

"The Department of Defense fostered the Internet, GPS, computer software, and other economically important innovations. Today, our uniformed men and women and their civilian counterparts are committed to transforming the way the department uses energy through efficiency and technology development. Their accomplishments and innovations are enhancing our national security, our economic security, and our environmental security," Warner said in a statement.


Grant Helps Researchers Develop Better Solar Cells for Spacecraft: NASA Funding to Power Satellites

Sept 23, 2011

The funds, administered by the Arkansas NASA-EPSCoR office at the University of Arkansas at Little Rock, will enhance research opportunities in the state and could create high-tech jobs. The National Science Foundation initiated EPSCoR - the Experimental Program to Stimulate Competitive Research - to encourage local action to develop long-term improvements in a state's science and engineering enterprise.

"This research will have a significantly positive impact on the quality and competitiveness of the state's academic research enterprise," said Omar Manasreh, professor of electrical engineering at the University of Arkansas. "It will create new opportunities for further development in the field of novel photovoltaic materials and devices."

The three-year grant totals slightly more than $1 million. As principal investigator, Manasreh will receive $710,646 - $473,764 from NASA and $236,882 in cost-sharing funds from the University of Arkansas. Liangmin Zhang, assistant professor at Arkansas State University, will receive $171,235 from NASA and $85,617 from ASU. UALR will receive $90,000 from NASA to cover administrative costs.

The funding will allow researchers in Manasreh's Optoelectronics Research Lab to continue growing and functionalizing semiconductor and metallic nanoparticles to be used in solar cells. He said this work could eventually lead to the start of a private company based in Arkansas. In 2010, Manasreh received a five-year $1.13 million grant from the U.S. Air Force Office of Scientific Research, which included cost sharing from the University of Arkansas, to pursue similar and complementary work.

The ultimate goal is to fabricate and test a photovoltaic device that is capable of possessing a solar energy conversion efficiency of 40 percent or better. Currently, solar panels used on NASA satellites and spacecraft use silicon-based technology, which cannot produce light-to-energy conversion efficiency greater than 23 percent.

Manasreh employs two approaches to fabricate solar cells. Instead of silicon, the first approach involves a combination of copper, indium, gallium and selenium (CuInSe2 and CuInGaSe2) as the semiconductor material to grow nanocrystals. The researchers make the nanocrystals functional by generating volatile ligands, which are molecules that bind to a central atom. The nanocrystals are then either converted into thin films or combined with titanium dioxide or zinc oxide nanotubes to create the desired solar cells. After fabrication of the cells, the researchers will test and evaluate their performance.

The second approach uses molecular beam epitaxy, a method of depositing nanocrystals, to create quantum dots made of indium arsenide (InAs). Quantum dots are nanosized particles of semiconductor material.

To enhance the performance of the solar cells, the researchers will use short ligands to couple metallic nanoparticles to the nanocrystals and quantum dots. They will then investigate the plasmonic effect of trapping sun light, which in turn increases the energy conversion efficiency. Just as a photon is the quantum of the electromagnetic waves, a plasmon is the quantum of charge waves generated by light.

Manasreh is member of the Institute for Nanoscience and Engineering at the University of Arkansas. His research has focused on experimental and theoretical optoelectronic properties of semiconductors, superlattices, nanostructures and related devices. He has worked extensively with electronic and optoelectronic applications, photovoltaic materials and devices and growth of nanomaterials. His recent work has focused on optoelectronic devices such as multi-color detectors and infrared detectors for focal plane arrays. Since joining the University of Arkansas in 2003, he has received more than $8 million in public research funding. This funding has been used to establish a state-of-the-art research lab with instrumentations ranging from nanomaterial characterization and device fabrication to device testing and evaluation.

Source: University of Arkansas

Thursday, 22 September 2011

Graphene can be strengthened by folding

Sept 22, 2011

The researchers, Yongping Zheng and Zhigao Huang of Fujian Normal University in China; Ning Wei and Zheyong Fan of Xiamen University in China; and Lanqing Xu of both universities, have published their study in a recent issue of Nanotechnology.

“The results of this work provide a new route for tailoring the properties of graphene-based nanomaterials,” Zheng told “Currently, many researchers and engineers are concerned with doping, alchemy, etc. We have demonstrated here that structure re-construction could also lead to interesting results.”

In their study, the researchers used molecular dynamics simulations to investigate grafold. They compared graphene with grafold in two areas: tension (the force that pulls the material apart) and compression (the force that pushes the material together). The ability to be both elongated and squeezed without damage is very helpful for engineering applications. However, as the researchers explain, graphene only has a high tensile strength; because of its two-dimensional nature, it is “soft” under compression and can’t be squeezed.

In contrast, the researchers’ simulations showed that grafold is “harder” than graphene and can withstand much larger amounts of compression (10-25 GPa depending on the structure of grafold compared with less than 2 GPa for graphene). While its compressive strength is significantly higher than that of graphene, grafold’s tensile strength approaches that of graphene. The Young’s modulus (a measure of elasticity) and fracture strain of grafold are a little lower than those of graphene. The scientists noted that several other materials can withstand greater compression than grafold, including carbon nanotubes, which can be both elongated and squeezed like grafold.

“As is well known, graphene can’t withstand any compression,” Zheng said. “Via folding, graphene transforms into grafold and can be compressed to a certain amount. Even when highly compressed, it won’t break down, just be squeezed into a shorter folded belt. Furthermore, the deformation is elastic. As we know, if the strength exceeds carbon nanotubes’ breaking point, it will crash and never return to its original form.”

Among grafold’s advantages is that folding a graphene nanoribbon to create grafold will be much easier than rolling it up to create a carbon nanotube. Plus, grafold’s mechanical properties can be tuned by the modifying the folding design, such as changing the size, shape, and number of folds.

Overall, the results of the simulations provide a new route for tailoring the properties of graphene-based nanomaterials, which could lead to advanced mechanical applications. The researchers hope to experimentally fabricate grafold in the near future. “There could be versatile applications,” Zheng said. “Say, one could utilize the elastic and low-to-mid stiffness of grafold in applications where a large damping is required.”


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New energy in search for future wind

Sept 21, 2011

Scientists are taking the first steps to improve estimates of long-term wind speed changes for the fast-growing wind energy sector, intended to reduce the risks for generators in a changing climate.

Some recent international studies have shown a decrease in wind speeds in several parts of the globe, including across Australia. However, more recent results by CSIRO show that Australia's average wind speed is actually increasing.

Scientists at CSIRO Marine and Atmospheric Research have analysed wind speed observations to understand the causes of variations in near-surface wind and explore long-term wind speed trends over Australia.

"We have a good picture of wind energy availability across Australia from previous CSIRO wind mapping and, with the growth of wind farms, there is an emerging need to understand how climate change can affect the wind resource," says Dr Alberto Troccoli, lead author of the paper published in the Journal of Climate.

"Wind power production is expected to increase greatly over the coming years and the associated electricity system will be subject to variations of several hundred megawatts – depending on wind availability.

"The ability to quantify with accuracy these long-term variations is essential to the sector from an economic point of view," he said.
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