Intelligent absorbent removes radioactive material from water

Professor Huai-Yong Zhu from QUT Chemistry with the titanate nanofiber that can remove radioactive material from contaminated water

Nuclear power plants are located close to sources of water, which is used as a coolant to handle the waste heat discharged by the plants. This means that water contaminated with radioactive material is often one of the problems to arise after a nuclear disaster. Researchers at Australia's Queensland University of Technology (QUT) have now developed what they say is a world-first intelligent absorbent that is capable of removing radioactive material from large amounts of contaminated water, resulting in clean water and concentrated waste that can be stored more efficiently.
The new absorbent, which was developed by a QUT research team led by Professor Huai-Yong Zhu working in collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and Pennsylvania State University, uses titanate nanofiber and nanotube technology. Unlike current clean-up methods, such as a layered clays and zeolites, the new material is able to efficiently lock in deadly radioactive material from contaminated water and the used absorbents can then be safely disposed of without the risk of leakage - even if the material were to become wet.
When the contaminated water is run through the fine nanotubes and fibers, the radioactive Cesium (Cs+) ions are trapped through a structural change. Additionally, by adding silver oxide nanocrystals to the outer surface, the nanostructures are able to capture and immobilize radioactive iodine (I-) ions used in treatments for thyroid cancer, in probes and markers for medical diagnosis, and also found in leaks of nuclear accidents.
"One gram of the nanofibres can effectively purify at least one ton of polluted water," Professor Zhu said. "This saves large amounts of dangerous water needing to be stored somewhere and also prevents the risk of contaminated products leaking into the soil."
"Australia is one of the largest producers of titania that are the raw materials used for fabricating the absorbents of titanate nanofibres and nanotubes. Now with the knowledge to produce the adsorbents, we have the technology to do the cleaning up for the world," added Professor Zhu.

Researchers identify enzyme that holds key to living longer through calorie restriction

Restricting calorie intake has been shown to delay the aging process and the enzyme Prx1 has been identified as playing a major role

Studies have shown that restricting the intake of calories without reducing the intake of vitamins and minerals slows the sign of aging process in a wide range of animals including monkeys, rats and fish, and even some fungi. More recent studies provide evidence that calorie restriction can also have the same effect on humans and now researchers at the University of Gothenburg have identified one of the enzymes they claim plays a major role in the aging process.
Although calorie restriction has been shown to slow the aging process, delay the development of age-related diseases and have favorable effects on health, researchers have had a hard time explaining why this is so. Using yeast as a model, researchers at the University of Gothenburg have successfully identified that active peroxiredoxin 1 (Prx1), an enzyme that breaks down harmful hydrogen peroxide in the cells, is required for caloric restriction to work effectively.
The research team's study showed that Prx1 is damaged during aging and loses its activity but caloric restriction counteracts this by increasing the production of another enzyme called Srx1, which repairs Prx1. In potentially good news for those that like their food, the team also found that aging can be delayed without caloric restriction by increasing the quantity of Srx1 in the cell.
"Impaired Prx1 function leads to various types of genetic defects and cancer. Conversely, we can now speculate whether increased repair of Prx1 during aging can counteract, or at least delay, the development of cancer," said Mikael Molin of the University of Gothenburg's Department of Cell and Molecular Biology.
The researchers say that it has also been shown that peroxiredoxins are capable of preventing proteins from being damaged and aggregating, a process that has been linked to several age-related disorders affecting the nervous system, such as Alzheimer's and Parkinson's. Therefore, they are also considering whether stimulation of Prx1 can reduce and delay such disease processes.
The University of Gothenburg team's study, Life Span Extension and H2O2 Resistance Elicited by Caloric Restriction Require the Peroxiredoxin Tsa1 in Saccharomyces cerevisiae has been published in the journal Molecular Cell.

New paper-based explosives sensor is made with an ink jet printer

Wireless explosives sensor that has been inkjet-printed on photographic paper 

There's never been a greater need for explosives detectors. From detecting IEDs on the battlefields of Afghanistan to screening cargoes at airports and sea terminals for bombs or illegal arms shipments, the need to seek out and identify explosives means deploying detectors to hundreds of thousands of locations around the world. Unfortunately, there has always been an unpleasant trade off when it comes to explosives detection sensors - they are either cheap, but not very sensitive or they are very sensitive, but also expensive. They are also often difficult to manufacture, use a good deal of power, are relatively delicate and require a trained operator.

Along with traditional sniffer dogs, many ideas are under development to improve explosives detection technology such as lasers, UV-sensitive sprays, terrahertz radiation scanners and even sensors using bee-venom
. Most of the very sensitive sensors that can detect very minute quantities of explosives at a distance are based on ion mobility spectrometers (IMS). Put simply, these work by ionizing the molecules in an air sample and then measuring how fast they pass through a "drift tube". It's a very sensitive and accurate way of detecting tiny traces of explosives, but it still suffers from requiring very expensive, hard to construct equipment. If only there was an alternative that was potentially as sensitive, but as cheap as printing a document. Then it would be possible to deploy detectors far and wide at much lower cost.
It turns out, there is now such an alternative. At the Georgia Tech Research Institute (GTRI), a team lead by principal research scientist Dr. Krishna Naishadham have created an ink-jet printable ammonia sensor capable of cheap, practical explosives detection. Ammonia is a key ingredient in the manufacture of many explosives.
The process of creating the sensor involves printing carbon nanotubes on paper or "paper-like" materials, such as the plastic polyethylene terephthalate. The ink consists of silver nanoparticles held in an emulsion that can be passed through an ink-jet printer at a temperature of only 212 F (100 C). This ink is treated with ultrasonic waves in a process known as sonification, which alters the viscosity and makes the ink more homogeneous for greater effectiveness. As it sets, the ink forms into nanoscale cylinders called nanotubes. These are only one-billionth of a meter in diameter-about 1/50,000th the width of a human hair. When these nanotubes are coated with a conductive polymer that attracts ammonia it becomes an effective explosives sensor capable of detecting trace amounts of ammonia as low as five parts per million. With different coatings, the nanotubes can detect other gases.

Xiaojuan (Judy) Song and Krishna Naishadham and display two prototype wireless explosives detector devices (Photo: Greg Meek, Georgia Tech)

Explosives detector and communication device

Not only is this process cheap and effective, but the nanotubes can also be formed into RF circuits, components and antennae. This means that the sensor can be printed with a built-in communications device already installed to transmit data. These components can be printed on a suitable plastic and be formed out of flexible organic materials, such as liquid crystal polymer to make them more robust and water resistant. The device also uses very little power, which makes it suitable for running off of thin-film batteries or solar cells. And, being printed, the device can be stuck on any surface where it might be required. The GTRI team is also working to make the device capable of operating passively without an internal power source-something like RFID tags used in shops that get their power from the shop's scanning devices..
This makes for a very flexible little package. The GTRI team designed the detector to act as an integrated detection/transmission system that provides stand-off explosives detection that allows personnel to remain at a safe distance while the detector transmits the results back to the operators.
"This prototype represents a significant step toward producing an integrated wireless system for explosives detection, says Dr. Naishadham. "It incorporates a sensor and a communications device in a small, low-cost package that could operate almost anywhere."
If it lives up to its promise, the printable explosives detector could deliver vitally needed, life-saving detectors that can be mass produced cheaply in any corner of the world.

Solar Ship: The hybrid airship with a low-carbon twist

The Solar Ship could be used for a variety of applications - including tourism
In recent times there's been a resurgence of interest in airships for military and commercial uses as evidenced by Lockheed Martin's High Altitude Long Endurance-Demonstrator (HALE-D) and Hybrid Air Vehicles heavy-lift variant of Northrop Grumman's Long-Endurance Multi-Intelligence Vehicle (LEMV). Like HAV's design, this concept from Canadian company Solar Ship is a hybrid airship that relies on aerodynamics to help provide lift, and like the HALE-D, it would have its top surface area covered in solar cells to provide energy and minimize its carbon footprint.

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Although the Solar Ship aircraft would be filled with helium, under normal circumstances they would rely on the aerodynamic lift provided by their wing shape to provide more than half the lift required to get them off the ground. Additionally, the aircraft could also fly when filled with plain old air. This means the aircraft will still be able to fly - and, more importantly, land safely - if there is damage that results in helium loss.
Solar Ship says the aircraft's electric motor can either be powered solely by the energy provided by the on board batteries, or by the solar panels covering the wing - a feat already achieved by a conventional airplane design in the form of Solar Impulse.

The company points out that such heavier-than-air airships provide numerous advantages over their lighter-than-air brethren. Firstly, no mooring infrastructure or ballast weight is required to keep the aircraft from floating away during loading or unloading, making them more practical for the remote locations in which they are designed to operate. Additionally, not relying on buoyancy for lift means the aircraft can be smaller than lighter-than-air aircraft carrying the same payload. They are also more structurally robust and more maneuverable and resistant to wind and weather conditions.

Small, medium, large

Solar Ship has designed three different concept aircraft, the smallest of which is the Caracal. This design has a claimed payload capacity of up to 750 kg (1,653 lb) for 2,500 km (1,553 miles) with a maximum speed of 120 km/h (75 mph).
Designed for remote areas where roads are a rarity and targeted at general, utility and ISR (Intelligence, Surveillance and Reconnaissance) markets, the Caracal can take off and land on strips as short as 50 m (164 ft) long but carrying the maximum payload requires strips of 100 m (328 ft).
Next step up in size is the mid-size Chui, which is targeted at ISR and cargo markets. Under solar power it can carry up to 2,500 kg (5,512 lb) over distances of up to 5,000 km (3,107 miles) at speeds of up to 100 km/h (62 mph). The take off and landing distances of the Chui are the same as the Caracal - 50 m (164 ft) empty and 100 m (328 ft) when fully loaded.

The third and largest Solar Ship class is the Nanuq, a dedicated cargo freighter designed to carry payloads of up to 30 tonnes (66,139 lb) for distances of up to 6,000 km (3,728 miles) at speeds of up to 120 km/h (75 mph). Empty the Nanuq can take off on strips 60 m (197 ft) long and land on strips 100 m (328 ft) long, while fully loaded requires a take off distance of 200 m (656 ft).
Solar Ship has already built and flown a 10 m (33 ft) prototype. The promotional video below provides a glimpse of the company's vision for the future in which it sees a wide range of uses for its heavier-than-air aircraft, from delivery of urgent medical supplies to remote communities and disaster relief, to environmental monitoring and military applications.
... and with several company's floating short take off hybrid airship platforms, this is definitely a space to watch over the next decade.

New method may lead to improved detection of nuclear materials

Scientists at Northwestern University have published details of a new method for detection of 'hard radiation'

Scientists at Northwestern University, Illinois, have outlined a new method for detecting electromagnetic radiation at the high energy end of the spectrum. The work could lead to the development of a small, hand held device able to detect this "hard radiation" and has implications for the detection of radioactive materials which could potentially be employed in terrorist weapons, such as nuclear bombs or radiological dispersion devices, as well as materials employed in clandestine nuclear programs.

The threat

Even a very crude bomb resulting in a so-called "fizzle" yield may have enough energy to bring down a large building, and the release of initial radiation and fallout would be extremely hazardous in a populated area. Investigation of such threats is the responsibility of bodies such as the US Department of Energy's National Nuclear Security Administration and any new tools they may acquire can only be of benefit to the general population.

A new innovation

The Northwestern University scientists' response to this challenge comes in the form of a method they've called "dimensional reduction" which involves the creation of new semiconductor materials using heavy elements in which the majority of electrons are bound and unable to move.
"The terrorist attacks of 9/11 heightened interest in this area of security, but the problem remains a real challenge," said Mercouri G. Kanatzidis, who led the research. "We have designed promising semiconductor materials that, once optimized, could be a fast, effective and inexpensive method for detecting dangerous materials such as plutonium and uranium."
When incoming electromagnetic radiation hits the material, the resulting excitement of these "bound" electrons can be analyzed to determine what element is emitting the radiation. This would be extremely useful in assessing any potential threat.
Because heavy elements typically have a lot of mobile electrons, detecting the small changes in their excited states is a difficult task. The teams' solution was to find a dense material with a crystalline structure in which electrons would be mobilized when hard radiation was absorbed.
The researchers have had successful results with two materials: cesium-mercury-sulfide and cesium-mercury-selenide. A big advantage of these materials is that they can be employed for hard radiation detection at room temperature, unlike previously existing semiconductor detection materials such as High-Purity Germanium (HPGe) which are typically cooled using liquid nitrogen.
The end result of Kanatzidis' research may be hand held device able to detect high energy radiation which typically just passes right through most materials. For example, a geiger counter may detect some gamma radiation but at the high energy end of the spectrum the photons can pass through undetected.
There could also be civil applications for the new method such as in the field of medical imaging.
The Northwestern University research has been supported by the Department of Homeland Security and the Defense Threat Reduction Agency and is published in the journal Advanced Materials.

SteriPEN Freedom offers USB-powered water purification

The SteriPEN Freedom is a USB-rechargeable portable UV water purifier

Water purifier manufacturer SteriPEN has updated its lineup of portable products, with a UV-based unit called the SteriPEN Freedom. Billed as the smallest, lightest and first rechargeable UV water purifier on the market, it disinfects up to 16 oz (0.5 L) of water in 48 seconds.
We've previously covered numerous water purification solutions for the developing world, with LifeStraw, Moringa tree seeds, or even banana peels being notable examples. The new SteriPEN device, however, is defined as hiking and camping equipment by its manufacturer, rather than as a life-saving tool.
The Freedom features a germicidal UV light which destroys 99.9 percent of bacteria, viruses and protozoa. Forty-eight seconds is enough for the Freedom to deal with half a liter of water, while a liter simply requires repeating this operation. A green light gauge indicates when it's safe to drink the water.
Recharged via a micro USB B port from a computer, AC outlet or a compatible solar charger, the Freedom offers up to 40 treatments on a single charge. The overall battery and UV lamp life is estimated to last for 8,000 treatments of 16 oz (0.5 L). The device also serves as a flashlight.
Equipped with a removable lamp cover, the new purifier weighs in at 2.6 oz (74 g) and measures 13 x 3.5 x 2.2 cm (5.1 x 1.4 x 0.8 in). Sold with a USB cable, AC adapter and neoprene case, the SteriPEN Freedom will be available starting this fall (northern hemisphere), priced at US$119.95.

Sportiiiis turns ordinary sunglasses into heads up display eyewear for cyclists

Sportiiiis HUD for athletes can be mounted on virtually all glasses, wirelessly pairs with perfromance monitoring equipment and feeds back workout information to the user via colored LEDs and audio

Canada's 4iiii Innovations has developed a Head Up Display for athletes that can be mounted on virtually all glasses thanks to included universal attachment points, so there's no need to stop wearing your favorite pair of sport sunglasses. Sportiiiis - pronounced "sport-eyes" - receives crucial performance data from any paired monitoring device via ANT+ wireless technology, compares actual performance with desired workout zone parameters and then feeds real-time indicators back to the user via colored LED lights and audio updates.

Unlike systems like the SportVue retro-fit HUD for motorbike and bicycle helmets or the Transcend ski goggles, Sportiiiis doesn't offer graphic visuals that might cause cyclists to look away from the road ahead at a critical moment. Performance feedback from paired ANT+ devices such as heart rate monitors, power meters, and cadence or speed modules is provided via a simple LED notification system that informs wearers whether they're within a pre-configured optimum workout zone.
If the cyclist or runner sees a red LED light up on the flexible boom that sits in the space between the lens of the chosen eyewear and the user's eye, the athlete is working too hard and needs to ease off a little. Green means the user is in the zone and yellow or orange is somewhere in between.

The water-resistant device also features a built-in speaker for providing audio feedback - in English only at the moment but the company is working on other language packs - and doesn't cover the ear so is safe to use on the road or track. Tapping on the side of the unit prompts an instant audio update and double-tapping cycles through the paired devices.
Users configure the seven multi-colored LEDs and instruct the unit to respond to input from any ANT+ device using Mac, PC or smartphone software. Both the brightness of the LEDs and the volume of the speaker can be adjusted on the unit or via compatible Android/iOS smartphone applications. The company also says that the onboard battery should be good for around ten hours.
The Sportiiiis HUD for cyclists and runners is available from next month, prices start at US$199.

Pavegen tiles harvest energy from footsteps

Pavegen tiles harvest kinetic energy from pedestrian traffic

Can you imagine the power of 50,000 steps a day? Well, Laurence Kembell-Cook, the director of Pavegen Systems imagined it and created Pavegen tiles - a low carbon solution that aims to bring kinetic energy harvesting to the streets. Not surprisingly, the tile is receiving a great deal of attention as a solution for power-hungry cities with a lot of walking traffic.

Designed for use in in high foot-traffic areas, the tiles convert the kinetic energy from footsteps of pedestrians into renewable electricity, which can be stored in a lithium polymer battery or used to power low-wattage, off-grid applications like street lighting, displays, speakers, alarms, signs, and advertising.
Each time someone steps on the tile, a central light illuminates, "connecting" the person to the part they play in producing the 2.1 watts of electricity per hour the tiles can generate (and providing self-sufficient lighting for pedestrian crossings).

The tiles are made from nearly 100-percent recycled materials (mostly rubber) and some marine grade stainless steel. They can be retrofitted to existing structures and are waterproof as well as designed to withstand outdoor conditions.
Pavegen tiles were used as a dance floor at Bestival on the Isle-of-Wright and are currently being tested in East London. They have been successfully installed in a school corridor where they are currently being monitored for durability and performance while helping to power the building. Speaking of durability, each tile is claimed to have a life of approximately 20 million steps or 5 years.
In September 2011 Pavegen received its first commercial order for the London 2012 Olympics Site where they will be used in the crossing between the Olympic stadium and the Westfield Stratford City Shopping Center.

Bosco Verticale: the world's first vertical forest

Bosco Verticale is a planned 10,000 square meter urban forest, which will grow upwards.
Italian architecture firm Stefano Boeri Architetti hopes to merge vegetation and urban architecture, with its Bosco Verticale (Vertical Forest) project. The Milan-based firm has designed a model that could see the "reforestation and naturalization" of metropolitan cities, by growing forests sky-ways. "Bosco Verticale [is a] device for the environmental survival of contemporary European cities," says Stefano Boeri.

Milan will host the first example of Bosco Verticale, with two residential towers already planned for construction. The towers, measuring 110 and 76 meters (361 and 250 feet), will become home to over 900 trees and that's excluding a wide range of shrubs and floral plants. The basic idea is that if you were to take the building out of the picture, the amount of trees needed to plant a forest on the land surface should be equal to those growing vertically on the tower. In essence, you will be creating a 10,000 square meter (11,960 sq. yds.) forest, growing upwards.
The project also aids in filtering air pollution contained in the urban environment. This is achieved as the the plants help produce humidity, absorb CO2 and dust particles, and produce oxygen. This will improve the quality of living for the residents, and it also creates a canopy that protects the building from radiation and noise pollution.
An irrigation and filtering system will be installed, that recycles gray water for maintenance of the plants. Photovoltaic solar cells will help contribute to the building's energy self-sufficiency.
Bosco Verticale will cost EUR65 million (US$87.5 million) and is stage one of the proposed BioMilano, which is hoped to create a green belt around the city.

Nissan doubles power density with new Fuel Cell Stack

Nissan yesterday revealed a new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV) that packs 85 kilowatts into a 34-liter package

One area of energy storage that appears to be moving towards viability quicker than battery technology at present is the hydrogen fuel cell. Nissan Motor yesterday revealed its next generation Fuel Cell Stack (2011 Model) for Fuel Cell Electric Vehicles (FCEV).
Through improvements to the Membrane Electrode Assembly and the separator flow path, Nissan has improved the power density of the Fuel Cell Stack to 2.5 times greater than its 2005 model, and in so doing has created a world's best 2.5 kW-h per liter power density.
The cost of the 2011 model Fuel Cell Stack has been reduced to one sixth of the 2005 model.
Furthermore, molding the supporting frame of the Membrane Electrode Assembly (MEA) integrally with the MEA's single-row lamination has reduced its size by more than half compared to conventional models.
Compared with the 2005 model, both the usage of platinum and parts variation has been reduced to one quarter, thereby reducing cost of the Next Generation Fuel Cell Stack to one-sixth of the 2005 model.
In so doing, Nissan engineers have achieved an important breakthrough with the development of a compact and durable hydrogen fuel-cell stack - capable of delivering ample power - that can be manufactured in volume at competitive cost.
Most importantly, it's not one of those Japanese research lab breakthroughs that's still effectively ten years away. Nissan's fuel-cell team says it can be ready for market as soon as sufficient supplies of hydrogen are available.
According to Nissan, taxis, delivery vans and other city-specific fleets could quickly be converted to zero-emission fuel cells.
"We never got discouraged and we never gave up," says Masanari Yanagisawa, a 10-year veteran in the company's fuel-cell R&D efforts. "So we just kept working, patiently and persistently. As a result, we have achieved what we believe is a major breakthrough.
"We have made great strides in two critical areas: power density and cost. Our 2011-model fuel-cell stack delivers power density at 2.5 kilowatt-hrs per liter, 2.5 times better than our 2005 model.
"As a result, the new stack is also a lot smaller. We can now pack 85 kilowatts of power in a 34-liter package. Better yet, we have brought the production cost down by 85 percent, close to meeting the U.S. Department of Energy cost target for 2010 - a widely referenced benchmark.
"We slashed the price by reducing the need for platinum by 75 percent," Yanagisawa says. "The Membrane Electrode Assembly [MEA] comprises 80 percent of the stack's cost, and platinum is half the cost of an MEA, so this was a huge step forward."
The other key challenge in developing fuel-cell stacks is to design a structure that delivers high power- density; that's durable and easy to manufacture without flaws. This is very tricky.
Each fuel cell is a carefully built sandwich with layers ultra-thin polymer electrolyte membrane. Each membrane has an anode layer and a cathode layer on both sides. On the outer side of each of each of these anode/cathode layers are separators, which form channels through which hydrogen, air and cooling water flow.
As each fuel cell generates a maximum of one volt, you need to stack lots of sandwiches together to get enough power to run a car.
The process is so fiddly that building a model ship in a bottle seems a snap by comparison. No wonder so many teams around the world have given up in frustration. But with their craft legacy of patient attention to minute detail, this is the kind of work that Japanese tend to excel at.
Since 2001, the Nissan team has built a succession of prototype fuel-cell vehicles, first with partners like Ballard Power Systems and UTC Fuel Cells, then in-house from 2005. Each stack was incrementally better than its predecessor.
The 2005 prototype achieved a range of 500 kilometers, matching a conventional car. A 2008 version achieved an important breakthrough in cold-weather tolerance. But putting enough cells together in a durable stack was a hurdle the team just couldn't get over. After managing to stack more than 400 cells, they would watch in frustration as the brittle contraption fell apart on the lab floor.
Finally, in 2009, the team had a conceptual breakthrough with a technique that involves molding plastic around the MEA to create insulating frames between each of 400+ layers in the stack - thereby ensuring the layers neither short out nor fall apart.
"This breakthrough puts us, no question, in the front rank of fuel-cell developers around the world," Yanagisawa says. "Best of all," he adds with a grin, "it puts us ahead of our competitors."
So can we expect to see a Nissan Fuel Cell Electric Vehicle (FCEV) coming round the corner soon? "We are now ready to go to market at any time," Yanagisawa says. "The only hurdle remaining is hydrogen distribution. Give us the hydrogen and we'll give you an FCEV. We're good to go!"

Waste glass could be used to clean water

Dr. Nichola Coleman and Cameron Abercrombie, a final year Chemistry student from the University of Greenwich

While you may feel quite virtuous when you leave all your glass containers out for recycling, you might be surprised to know that much of your colored glass won't be used. That's because even though there's a fairly constant demand for recycled clear glass, glass in colors such as green, brown and blue isn't all that sought-after, so many recycling centers don't bother processing it. As a result, waste colored glass is now being stock-piled in some locations, waiting for a use. Thanks to research conducted at the University of Greenwich, however, that glass may soon be used for filtering pollutants out of ground water.
Dr. Nichola Coleman, a senior lecturer in Materials Chemistry, has been leading the research.
Her team combined ground colored glass, lime and caustic soda, then heated the mixture to 100C (212F) in a sealed stainless steel container. This transformed the ingredients into tobermorite, a mineral that is effective at removing heavy metals from ground- or waste-water streams. She is hoping to incorporate the tobermorite into filtration devices, that could be used to prevent water-borne pollutants from spreading from contaminated areas.
"The novelty of the research is that the glass can be recycled into something useful," the U Greenwich researcher stated. "Nobody has previously thought to use waste glass in this way."
A paper on the research was recently published in the International Journal of Environment and Waste Management.

Graphene “Big Mac” brings next gen computer chips a step closer

Researchers have sandwiched layers of graphene between layers of boron nitrate to create a graphene 'Big Mac'
Since its discovery in 2004, the two-dimensional layer of carbon atoms known as graphene has promised to revolutionize materials science, enabling flexible, transparent touch displays, lighter aircraft, cheaper batteries and faster, smaller electronic devices. Now in what could be a key step towards replacing silicon chips in computers, researchers at the University of Manchester have sandwiched two sheets of graphene with another two-dimensional material, boron nitride, to create what they have dubbed a graphene "Big Mac".
The researchers used two layers of boron nitrate to not only separate two graphene layers, but also to see how graphene reacts when it is completely encapsulated by another material. The researchers say this has allowed them, for the first time, to observe how graphene behaves when unaffected by the environment and demonstrates how graphene inside electronic circuits will probably look in the future.
"Creating the multilayer structure has allowed us to isolate graphene from negative influence of the environment and control graphene's electronic properties in a way it was impossible before," said Dr Leonid Ponomarenko. "So far people have never seen graphene as an insulator unless it has been purposefully damaged, but here high-quality graphene becomes an insulator for the first time."
"Leaving the new physics we report aside, technologically important is our demonstration that graphene encapsulated within boron nitride offers the best and most advanced platform for future graphene electronics," added Professor Andre Geim who, along with Professor Kostya Novoselov, was awarded the Nobel Prize for Physics last year for the discovery of graphene at the University of Manchester in 2004.
"It solves several nasty issues about graphene's stability and quality that were hanging for a long time as dark clouds over the future road for graphene electronics. We did this on a small scale but the experience shows that everything with graphene can be scaled up," said Geim. "It could be only a matter of several months before we have encapsulated graphene transistors with characteristics better than previously demonstrated."
The research team's paper, Tunable metal-insulator transition in double-layer graphene heterostructures appears in the journal Nature Physics.

Collaboration aims to improve methods for detecting contaminants in water supplies

Dr. Shane Snyder is working with Agilent to develop ways to detect emerging contaminants in water

Agilent Technologies has announced it will begin collaborations with the University of Arizona's Department of Chemical and Environmental Engineering's BIO5 Institute to develop ways to detect and treat emerging contaminants in drinking water. While a considerable body of work has been done in the area of potable water quality and safety this research stands apart from the rest in the way it treats contaminants as mixtures rather than separate chemicals that are usually targeted individually.
Dr. Shane Snyder - an internationally recognized authority on water contamination from the University of Arizona's Department of Chemical and Environmental Engineering who will be heading-up the project explains: "Not only will we investigate known potential threats to water quality, we will also bridge the gap between detection and health by developing methodologies that can screen water for toxicity from multiple compounds."

Emerging Contaminants

While the issue of unsafe drinking water is commonplace in developing countries it is not often thought of in areas such as the United States or Europe. We take clean and safe drinking water for granted because organizations such as the EPA have got our backs on this one - delivering potable water to our homes each and every day. In recent years a new class of contaminant known as "emerging contaminants" has come to light. A study conducted in 2000 by the US Geological Survey's (USGS) Toxic Substances Hydrology Program revealed that of the 139 streams they examined 80 per cent contained emerging contaminants. The most common chemicals found were steroids, antibiotics, non-prescription drugs, caffeine and insect repellent.
Move forward to September 2009 when the EPA released the Contaminant Candidate List 3 (CCL3), a list of 116 drinking water contaminants. These include pharmaceuticals, pesticides, disinfection by-products, chemicals from manufacturing, waterborne pathogens, and biological toxins. An example of example one of these is the active pharmaceutical ingredients (APIs), a class that contains steroids such as cortisone.
These APIs can end up in waste water as a result of bathing, where a person has say been applying cortisone topically to their sore hamstring. These APIs can then make their way into the drinking water and into your body. The effect on humans of consuming such contaminants is still largely unknown however studies on fish that live in streams contaminated by steroids have shown significant hormone disruption. There is also concern that exposure to antibiotics in drinking water could increase the occurrence of drug-resistant strains of bacteria and diseases.

University of Arizona

So ... back to the new research. Agilent Technologies Inc. and University of Arizona's Department of Chemical and Environmental Engineering's collaboration hopes to increase the ability of scientists to accurately detect contamination in water supplies in order to protect the environment and public health.
"The partnership with Agilent allows the University of Arizona to more effectively influence water reuse and desalination strategies by ensuring that the required water quality has been achieved for its intended use," said Dr Snyder.
The deal will see Agilent provide the university and BIO5 with detection equipment. This includes technology that enables the development of chemical signatures unique to a particular water source.
The research will be centered at the BIO5 Institute on the University of Arizona campus, where the infrastructure for cross-cutting work combining biological and chemical research already exists.

UCLA researchers discover rhythmic secrets of the brain

UCLA neuro-physicists have discovered that changes in synaptic strength have an optimal 'rhythm,' or frequency

Neuroscientists have long pondered the mechanism behind learning and memory formation in the human brain. On the cellular level, it's generally agreed that we learn when stimuli are repeated frequently enough that our synapses - the gap-connections between neurons - respond and become stronger. Now, a team of UCLA neuro-physicists has discovered that this change in synaptic strength actually has an optimal "rhythm," or frequency, a finding that could one day lead to new strategies for treating learning disabilities.
"Many people have learning and memory disorders, and beyond that group, most of us are not Einstein or Mozart," said Mayank R. Mehta, one of the study's co-investigators. "Our work suggests that some problems with learning and memory are caused by synapses not being tuned to the right frequency."
The tendency for connections between neurons to grow stronger in response to repeated stimuli is known as synaptic plasticity. The series of signals one neuron gets from the others to which it's connected, dubbed "spike trains," arrive with variable frequencies and timing, and it's these trains that induce formation of stronger synapses- the very basis for "practice makes perfect."
In previous studies, it was shown that very high frequency neuronal stimulation (about 100 spikes per second) led to stronger connecting synapses, while stimulation at a much lower frequency (one spike per second) actually reduced synaptic strength. But real-life neurons, performing routine behavioral tasks, only fire 10 or so consecutive spikes, not hundreds, and they do this at a far lower frequency - around 50 spikes per second.
Achieving experimental spike rates that more closely approximate real life has proved rather elusive, however. Mehta explains one of the variables they encountered: "Spike frequency refers to how fast the spikes come. Ten spikes could be delivered at a frequency of 100 spikes a second or at a frequency of one spike per second."
But Mehta and his co-investigator, Arvind Kumar, didn't let that hurdle stop them. Instead, they worked out a complex mathematical model and validated it with actual data from their experiments. Now able to generate spike patterns closer to those that occur naturally, the team discovered that, contrary to their predictions, neuron stimulation at the highest frequencies wasn't the ideal way to bolster synaptic strength.
"The expectation, based on previous studies, was that if you drove the synapse at a higher frequency, the effect on synaptic strengthening, or learning, would be at least as good as, if not better than, the naturally occurring lower frequency," Mehta said. "To our surprise, we found that beyond the optimal frequency, synaptic strengthening actually declined as the frequencies got higher."
The realization that synapses have optimal frequencies for learning prompted Mehta and Kumar to determine whether synapse location on a neuron had any specific role. They discovered that the more distant the synapse was from the neuron's bulbous main body, the higher the frequency it required for optimal strengthening. "Incredibly, when it comes to learning, the neuron behaves like a giant antenna, with different branches of dendrites tuned to different frequencies for maximal learning," Mehta said.
The team also revealed that aside from having optimal frequencies at which maximal learning occurs, synapses also strengthen best when those frequencies are exactly-timed in perfect rhythms. Take away the beat, they found, and even with the ideal frequency, synaptic strengthening is appreciably compromised.

The image shows a neuron with a tree trunk-like dendrite. Each triangular shape touching the dendrite represents a synapse, where inputs from other neurons, called spikes, arrive (the squiggly shapes). Synapses that are further away on the dendritic tree from the cell body require a higher spike frequency (spikes that come closer together in time) and spikes that arrive with perfect timing to generate maximal learning (Image: UCLA Newsroom)
As if these remarkable revelations weren't enough, they also discovered that a synapse's optimal frequency changes once it learns. The researchers feel that understanding of this fundamental could yield insight into treatments for conditions related to memory dysfunction (or the need to forget), such as post-traumatic stress disorder.
With additional study, these findings could possibly lead to the development of new drugs capable of "re-calibrating" faulty brain rhythms in people with memory or learning disorders. "We already know there are drugs and electrical stimuli that can alter brain rhythms," Mehta said.
"Our findings suggest that we can use these tools to deliver the optimal brain rhythm to targeted connections to enhance learning."
The research paper entitled Frequency-dependent changes in NMDAR-dependent synaptic plasticity is available online at Frontiers in Computational Neuroscience.

New device to generate electricity from human breathing

A simulated lung with the piezoelectric PVDF microband (in yellow) that vibrates as air flows past it 
One of the biggest hurdles facing the developers of biological implants is coming up with a power source to keep the implanted devices ticking. We've seen various technologies that could be used instead of traditional batteries (which require the patient to go under the knife so they can be replaced) such as wireless transmission of power from outside the body, biological fuel cells that generate electricity from a person's blood sugar, and piezoelectric devices that generate electricity from body movements or the beating of the heart. Now researchers have developed a device that could be used to generate electricity from a patient's breathing.
The device created by researchers at the University of Wisconsin-Madison relies on the piezoelectric effect - whereby an electrical charge accumulates in certain materials in response to mechanical stress. But instead of relying on body movements to create the mechanical stress, the UW-Madison team's device uses low speed airflow like that caused by normal human respiration to cause the vibration of a plastic microbelt engineered from a piezoelectric material called polyvinylidene fluoride (PVDF).
"Basically, we are harvesting mechanical energy from biological systems. The airflow of normal human respiration is typically below about two meters per second," says Materials Science and Engineering Assistant Professor Xudong Wang who created the device along with postdoctoral researcher Chengliang Sun and graduate student Jian Shi. "We calculated that if we could make this material thin enough, small vibrations could produce a microwatt of electrical energy that could be useful for sensors or other devices implanted in the face," said Wang.

To thin the PVDF material to micrometer scale while preserving its piezoelectric properties, Wang's team used an ion-etching process. Wang believes that, with improvements, the thickness of the material, which is biocompatible, can be controlled down to the submicron level and lead to the development of a practical micro-scale device that could harvest energy from the airflow in a person's nose.
Tests conducted by the team saw the device reach power levels in the millivolt range, but reached up to 6 volts with maximum airflow speeds. Wang and the UW-Madison team now plan to look for ways to improve the efficiency of the device. The team's research appears in the September issue of Energy and Environmental Science.

New material claimed to store more energy and cost less money than batteries

The low-cost, high-density energy-storage membrane, created at the National University of Singapore

Researchers from the National University of Singapore's Nanoscience and Nanotechnology Initiative (NUSNNI) have created what they claim is the world's first energy-storage membrane. Not only is the material soft and foldable, but it doesn't incorporate liquid electrolytes that can spill out if it's damaged, it's more cost-effective than capacitors or traditional batteries, and it's reportedly capable of storing more energy.
The membrane is made from a polystyrene-based polymer, which is sandwiched between two metal plates. When charged by those plates, it can store the energy at a rate of 0.2 farads per square centimeter - standard capacitors, by contrast, can typically only manage an upper limit of 1 microfarad per square centimeter.
Due in part to the membrane's low fabrication costs, the cost of storing energy in it reportedly works out to 72 cents US per farad. According to the researchers, the cost for standard liquid electrolyte-based batteries is more like US$7 per farad. This in turn translates to an energy cost of 2.5 watt-hours per US dollar for lithium-ion batteries, whereas the membrane comes in at 10-20 watt-hours per dollar.
Details on how the material works, along with data on factors such as charging/discharging times and longevity have not yet been released. Principle investigator Dr. Xie Xian Ning, however, has stated "The performance of the membrane surpasses those of rechargeable batteries, such as lithium ion and lead-acid batteries, and supercapacitors."
The NUSNNI team is now looking into opportunities for commercializing the technology.

Edible sponge captures and stores carbon dioxide

The Northwestern filter changes color when full of carbon dioxide, then changes back after being emptied

As concerns continue to rise over man-made carbon dioxide entering the atmosphere, various groups of scientists have begun developing filters that could remove some or all of the CO2 content from smokestack emissions. Many of these sponge-like filters incorporate porous crystals known as metal-organic frameworks (MOFs). Unfortunately, most MOFs are derived from crude oil, plus some of them contain toxic heavy metals. Researchers from Illinois' Northwestern University, however, recently announced that their nontoxic MOF sponge - made from sugar, salt and alcohol - is fully capable of capturing and storing CO2. As an added bonus, should you be really hungry, you can eat the thing.
The main ingredient in the edible MOF is gamma-cyclodextrin, which is a biorenewable naturally-occurring sugar derived from corn starch. Metals taken from salts such as potassium benzoate and rubidium hydroxide hold the sugar molecules in place, those molecules' precise arrangement within the crystals being essential to the capture of CO2.
"It turns out that a fairly unexpected event occurs when you put that many sugars next to each other in an alkaline environment - they start reacting with carbon dioxide in a process akin to carbon fixation, which is how sugars are made in the first place," said postdoctoral fellow Jeremiah J. Gassensmith. "The reaction leads to the carbon dioxide being tightly bound inside the crystals, but we can still recover it at a later date very simply."
Not only can the filters be emptied of CO2 and reused, but they also have a way of letting people know when they can't hold any more. Each crystal has an indicator molecule placed inside of it, which changes color according to the surrounding pH. When the whole sponge changes from yellow to red, that means that it has reached capacity. After being emptied, its color returns to yellow.
The Northwestern research was recently published in the Journal of the American Chemical Society.

Researchers turn wastewater into “inexhaustible” source of hydrogen

Penn State researchers have developed an electrolysis cell with RED stack that produces pure hydrogen from waste water
Currently, the world economy and western society in general runs on fossil fuels. We've known for some time that this reliance on finite resources that are polluting the planet is unsustainable in the long term. This has led to the search for alternatives and hydrogen is one of the leading contenders. One of the problems is that hydrogen is an energy carrier, rather than an energy source. Pure hydrogen doesn't occur naturally and it takes energy - usually generated by fossil fuels - to manufacture it. Now researchers at Pennsylvania State University have developed a way to produce hydrogen that uses no grid electricity and is carbon neutral and could be used anyplace that there is wastewater near sea water.
The researchers' work revolves around microbial electrolysis cells (MECs) - a technology related to microbial fuel cells (MFCs), which produce an electric current from the microbial decomposition of organic compounds. MECs partially reverse this process to generate hydrogen (or methane) from organic material but they require the some electrical input to do so.
Instead of relying on the grid to provide the electricity required for their MECs, Bruce E. Logan, Kappe Professor of Environmental Engineering, and postdoctoral fellow Younggy Kim, turned to reverse-electrodialysis (RED). We've previously looked at efforts to use RED to generate electricity using salt water from the North Sea and fresh water from the Rhine and the Penn State team's work follows the same principle - extracting energy from the ionic differences between salt water and fresh water.

A RED stack consists of alternating positive and negative ion exchange membranes, with each RED contributing additively to the electrical output. Logan says that using RED stacks to generate electricity has been proposed before but, because they are trying to drive an unfavorable reaction, many membrane pairs are required. To split water into hydrogen and oxygen using RED technology requires 1.8 volts, which would require about 25 pairs of membranes, resulting in increased pumping resistance.
But by combining RED technology with exoelectrogenic bacteria - bacteria that consume organic material and produce an electric current - the researchers were able to reduce the number of RED stacks required to five membrane pairs.
Previous work with MECs showed that, by themselves, they could produce about 0.3 volts of electricity, but not the 0.414 volts needed to generate hydrogen in these fuel cells. Adding less than 0.2 volts of outside electricity released the hydrogen. Now, by incorporating 11 membranes - five membrane pairs that produce about 0.5 volts - the cells produce hydrogen.
"The added voltage that we need is a lot less than the 1.8 volts necessary to hydrolyze water," said Logan. "Biodegradable liquids and cellulose waste are abundant and with no energy in and hydrogen out we can get rid of wastewater and by-products. This could be an inexhaustible source of energy."
While Logan and Kim used platinum as the catalyst on the cathode in their initial experiments, subsequent experimentation showed that a non-precious metal catalyst, molybdenum sulfide, had 51 percent energy efficiency.
The Penn State researchers say their results, which are published in the Sept. 19 issue of the Proceedings of the National Academy of Sciences, "show that pure hydrogen gas can efficiently be produced from virtually limitless supplies of seawater and river water and biodegradable organic matter."

Carbon nanotube-reinforced polyurethane could make for bigger and better wind turbines

Carbon nanotube-reinforced polyurethane could make for lighter and more durable wind turbine blades
In the effort to capture more energy from the wind, the blades of wind turbines have become bigger and bigger to the point where the diameter of the rotors can be over 100 m (328 ft). Although larger blades cover a larger area, they are also heavier, which means more wind is needed to turn the rotor. The ideal combination would be blades that are not only bigger, but also lighter and more durable. A researcher at Case Western Reserve University has built a prototype blade from materials that could provide just such a winning combination.
The new blade developed by Marcio Loos, a post-doctoral researcher in the Department of Macromolecular Science and Engineering, is the world's first polyurethane blade reinforced with carbon nanotubes. Using a small commercial blade as a template, Loos manufactured a 29-inch (73.6 cm) blade that is substantially lighter, more rigid and tougher than conventional blades. Rigidity is important because as a blade flexes in the wind it loses the optimal shape for catching air, so less energy is captured.
Working with colleagues at Case Western Reserve, and investigators from Bayer Material Science in Pittsburgh, and Molded Fiber Glass Co. in Ashtabula, Ohio, Loos compared the properties of the new materials with that of conventional blades manufactured using fiberglass resin.
"Results of mechanical testing for the carbon nanotube reinforced polyurethane show that this material outperforms the currently used resins for wind blades applications," said Ica Manas-Zloczower, professor of macromolecular science and engineering and associate dean in the Case School of Engineering.

Comparing reinforcing materials, the researchers found that the carbon nanotubes are lighter per unit of volume than carbon fiber and aluminum and had five times the tensile strength of carbon fiber and more than 60 times that of aluminum.
Meanwhile, fatigue testing showed the reinforced polyurethane composite lasts about eight times longer than epoxy reinforced with fiberglass, while delamination fracture tests showed it was also about eight times tougher. The performance of the material was even better when compared against vinyl ester reinforced with fiberglass, another material used to make wind turbine blades. Fracture growth rates were also a fraction of that found for traditional epoxy and vinyl ester composites.
Loos and her team are now working to determine the optimal conditions for the dispersion of the nanotubes, the ideal distribution within the polyurethane and the ways to achieve both.

Scientists claim that cars could run on old newspapers

Tulane associate professor David Mullin (right), postdoctoral fellow Harshad Velankar (center), and undergraduate student Hailee Rask have discovered a bacteria that converts the cellulose in newspapers to biofue
Hopefully, your old newspapers don't just end up in the landfill. In the future, however, they might not even be used to make more paper - instead they may be the feedstock for a biofuel-producing strain of bacteria. Named "TU-103," the microorganism was recently discovered by a team of scientists at New Orleans' Tulane University. It converts cellulose - such as that found in newspapers - into butanol, which can be substituted for gasoline.
"Cellulose is found in all green plants, and is the most abundant organic material on earth, and converting it into butanol is the dream of many," said team member Harshad Velankar. "In the United States alone, at least 323 million tons [293 million tonnes] of cellulosic materials that could be used to produce butanol are thrown out each year."
The scientists first discovered TU-103 in animal feces, and have since cultivated it, and developed a patent-pending process that allows it to produce butanol from cellulose. In their lab, they have had success using newspapers as the cellulose source. While other bacteria have been found to produce butanol in the past, they have all required an oxygen-free environment, which increases production costs. TU-103, on the other hand, is able to survive and function in the presence of oxygen.
Although ethanol is also derived from cellulose, butanol is reportedly superior to that biofuel in several ways - it can be used as is in all unmodified automobile engines, it can be pumped through existing pipelines, it is less corrosive, and it contains more energy.
"This discovery could reduce the cost to produce bio-butanol," said David Mullin, whose lab in Tulane's Department of Cell and Molecular Biology was the location of the research. "In addition to possible  savings on the price per gallon, as a fuel, bio-butanol produced from cellulose would dramatically reduce carbon dioxide and smog emissions in comparison to gasoline, and have a positive impact on landfill waste."

In-shoe device harvests energy created by walking

A new in-shoe device is designed to harvest the energy that is created by walking, and store it for use in mobile electronic devices


Although you may not be using a Get Smart-style shoe phone anytime soon, it is possible that your mobile phone may end up receiving its power from your shoes. University of Wisconsin-Madison engineering researchers Tom Krupenkin and J. Ashley Taylor have developed an in-shoe system that harvests the energy generated by walking. Currently, this energy is lost as heat. With their technology, however, they claim that up to 20 watts of electricity could be generated, and stored in an incorporated rechargeable battery.


While the details of the energy-harvesting technology are proprietary, it is said to involve a process known as "reverse electrowetting," which was discovered by Krupenkin and Taylor. It converts mechanical energy to electricity via a microfluidic device, in which thousands of moving microdroplets (of an undisclosed non-toxic, inexpensive liquid) interact with "a groundbreaking nanostructured substrate." The process is said to have a power density of up to one kilowatt per square meter (10.76 sq. ft.), plus it works with a wide range of mechanical forces, and is able to output a wide range of currents and voltages.

The battery is hermetically sealed, for protection against water and dirt. In order to get the power from it to the phone or other mobile device, the two would have to be temporarily physically joined with a wire, although the researchers are also looking into the use of conductive textiles and wireless inductive coupling.

Besides directly powering the phone, the device could also serve as a mobile WiFi hotspot, linking the phone to a wireless network. Having its own hotspot constantly nearby could drastically increase the phone's battery life - this is because the phone would only need to transmit in a low-power standard such as Bluetooth in order to reach the device, which would then use its own battery (which would be continuously getting recharged, by walking) for the high-power long-range transmissions to the network. Krupenkin claims that this could allow phone batteries to last up to ten times longer than normal.
The U Wisconsin technology is currently in the process of being commercialized, through Krupenkin and Taylor's company, InStep NanoPower. If it does make it to the marketplace, it may have some competition - Dr. Ville Kaajakari is also developing a piezoelectric device for shoes, that generates power as its user walks.