(NanoRealm) - In a revolutionary leap that could transform solar power from a marginal, boutique alternative into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.

Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera's lab, have developed an unprecedented process that will allow the sun's energy to be used to split water into hydrogen and oxygen gases. Later, the oxygen and hydrogen may be recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night.

The key component in Nocera and Kanan's new process is a new catalyst that produces oxygen gas from water; another catalyst produces valuable hydrogen gas. The new catalyst consists of cobalt metal, phosphate and an electrode, placed in water. When electricity — whether from a photovoltaic cell, a wind turbine or any other source — runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.





Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water splitting reaction that occurs during photosynthesis.

The new catalyst works at room temperature, in neutral pH water, and it's easy to set up, Nocera said. "That's why I know this is going to work. It's so easy to implement," he said.

'Just the beginning'

Currently available electrolyzers, which split water with electricity and are often used industrially, are not suited for artificial photosynthesis because they are very expensive and require a highly basic (non-benign) environment that has little to do with the conditions under which photosynthesis operates.

More engineering work needs to be done to integrate the new scientific discovery into existing photovoltaic systems, but Nocera said he is confident that such systems will become a reality.

"This is just the beginning," said Nocera, principal investigator for the Solar Revolution Project funded by the Chesonis Family Foundation and co-Director of the Eni-MIT Solar Frontiers Center. "The scientific community is really going to run with this."

Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electricity-by-wire from a central source could be a thing of the past.

The project is part of the MIT Energy Initiative, a program designed to help transform the global energy system to meet the needs of the future and to help build a bridge to that future by improving today's energy systems. MITEI Director Ernest Moniz, Cecil and Ida Green Professor of Physics and Engineering Systems, noted that "this discovery in the Nocera lab demonstrates that moving up the transformation of our energy supply system to one based on renewables will depend heavily on frontier basic science."

The success of the Nocera lab shows the impact of a mixture of funding sources — governments, philanthropy, and industry. This project was funded by the National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make the large scale deployment of solar energy within 10 years.

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Source: MIT News - http://web.mit.edu/newsoffice/2008/oxygen-0731.html

(NanoRealm) - A U.S. chemical engineer says he’s developed a way to make all-natural personal care products and purer pharmaceuticals in the laboratory.

Kansas State University Professor Peter Pfromm, in collaboration with former visiting doctoral student Kerstin Wurges, said he has engineered a way to use enzymes to efficiently catalyze chemical reactions to create such products as scents for perfumes or to avoid the introduction of inactive ingredients in drugs.

He said the process is essentially an enzyme-covered nanoparticle of fumed silica. Since enzymes come from natural organisms, the end product can be billed as natural, Pfromm said.
He said enzymes also can be used to make a purer form of pharmaceuticals, noting the active molecules in many drugs often come with an inactive twin. However, enzymes are very effective at only producing the active version of the molecule.

“Most of the time the inactive twin molecule is harmless, but there is a trend toward making more pure pharmaceuticals,” Pfromm said. “Enzymes are exceedingly good at taking reactants and making them into only one of the versions, not both. They are supremely selective in this way; chemical catalysts are not.”

Wurges, listed as a co-inventor on the process patent, worked with Pfromm on devising the preparation and did much of the lab work. She is presently pursing her doctorate at the Julich Research Center in Germany.

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Source: Ethopian Review (http://www.ethiopianreview.com/news/153650)

(NanoRealm) - The Shimizu Corporation, a Japanese construction firm, has recently proposed a plan to harness solar energy on a larger scale than almost any previously proposed concept. Their ambitious plan involves building a belt of solar cells around the Moon’s 6,800-mile (11,000-kilometer) equator, converting the electricity to powerful microwaves and lasers to be beamed at Earth, and finally converting the beams back to electricity at terrestrial power stations. The Luna Ring concept, the company says, could meet the entire world's energy needs.

Shimizu envisions that robots would play a vital role in building the Luna Ring. Teleoperated 24 hours a day from the Earth, the robots would perform tasks such as ground leveling and assembling machines and equipment, which would be done in space before landing them on the Moon. A team of astronauts would support the robots on-site.



Due to the massive amount of solar panels and other materials needed for the project, Shimizu proposes that lunar resources should be used to the fullest extent possible. The company’s plans call for producing water by reducing lunar soil with hydrogen imported from Earth. Lunar resources could also be used to make cementing material and concrete, while solar-heat treatments could help produce bricks, glass fibers, and other structural materials needed for the project.

The Luna Ring itself would initially have a width of a few kilometers, but could be extended up to 400 kilometers wide. The electric power generated by the solar cells would be transmitted by electric cables to transmission facilities on the near side of the Moon, which is constantly facing Earth. After the electricity is converted into microwave beams and laser beams, 20-kilometer-diameter antennas would beam the power to receivers on Earth. A guidance radio beacon would ensure accurate transmission to the receivers. The energy would then be converted back to electricity and supplied to grids, or possibly converted to hydrogen for fuel or storage.



Shimizu points out that one of the biggest advantages of the Luna Ring is that, since the Moon has virtually no atmosphere, there is no bad weather or clouds that could inhibit the efficiency of the solar panels. As such, the Luna Ring achieves 24/7 continuous clean energy generation, potentially ending our reliance on limited natural resources.

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Source: Shimuzu Corperation

(NanoRealm) - Banknotes could become as beautiful as butterfly wings one day using technology borrowed from nature.

British scientists have found a way to mimic the iridescent colours of tropical butterflies, created by light bouncing off microscopic wing structures.

The research could be used to make banknotes and credit cards that are visually striking and harder to forge.

“These artificial structures could be used to encrypt information in optical signatures on banknotes to protect them against forgery,” said Mathias Kolle, a PhD student at the University of Cambridge.

“In future we could see structures based on butterflies’ wings shining from a £10 note or even our passports.”

The Cambridge team studied the Indonesian peacock, or swallowtail, butterfly — Papilio blumei — whose vivid green-and-blue wings have an intricate surface pattern.

They made identical copies of the structures using nanotechnology.

Recreating the colours of beetles, butterflies and moths has previously proved elusive because of the technical challenge of precisely shaping materials on such a small scale.


“We have unlocked one of nature’s secrets and combined this knowledge with state-of-the-art nanofabrication to mimic the intricate optical designs found in nature,” Mr Kolle said.

“Although nature is better at self-assembly than we are, we have the advantage that we can use a wider variety of artificial, custom-made materials to optimise our optical structures.”

The research is published in the journal Nature Nanotechnology.

The Indonesian peacock may use the security potential of its wing structure to encrypt itself, the scientists believe.

“The shiny green patches on this tropical butterfly’s wing scales are a stunning example of nature’s ingenuity in optical design,” Mr Kolle said.

“Seen with the right optical equipment these patches appear bright blue but with the naked eye they appear green.

“This could explain why the butterfly has evolved this way of producing colour. If its eyes see fellow butterflies as bright blue, while predators only see green patches in a green tropical environment, then it can hide from predators at the same time as remaining visible to members of its own species.”

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TimesOnline UK: (http://www.timesonline.co.uk/tol/news/uk/article7140807.ece)

(NanoRealm) - A researcher at North Carolina State University has developed a computer chip that can store an unprecedented amount of data - enough to hold an entire library's worth of information on a single chip. The new chip stems from a breakthrough in the use of nanodots, or nanoscale magnets, and represents a significant advance in computer-memory technology.

"We have created magnetic nanodots that store one bit of information on each nanodot, allowing us to store over one billion pages of information in a chip that is one square inch," says Dr. Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and author of the research.
The breakthrough is that these nanodots are made of single, defect-free crystals, creating magnetic sensors that are integrated directly into a silicon electronic chip. These nanodots, which can be made uniformly as small as six nanometers in diameter, are all precisely oriented in the same way - allowing programmers to reliably read and write data to the chips.

The chips themselves can be manufactured cost-effectively, but the next step is to develop magnetic packaging that will enable users to take advantage of the chips - using something, such as laser technology, that can effectively interact with the nanodots.

The research, which was funded by the National Science Foundation, was presented as an invited talk April 7 at the 2011 Materials Research Society Spring Meeting in San Francisco.


More information: “Self Assembly of epitaxial magnetic nanostructures”, Author: J. Narayan, North Carolina State University, Presented: April 7, 2010, 2011 MRS Spring Meeting, San Francisco.

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Source: http://www.physorg.com/news191668936.html

(NanoRealm) - THE use of nano technology has helped the Government save RM3.44bil worth of subsidised diesel fuel from being smuggled out of the country between 2006 to 2008.

Nano technology ‘helped govt save RM3.44bil’

Domestic Trade, Cooperative and Consumerism Minister Datuk Seri Ismail Sabri Yaakob said the Nanotag technology or “mark” to identify subsidised fuel had helped enforcement officers track or identify subsidised diesel and to take legal action against the culprits.

“The Nanotag technology has enabled our officers to check the distribution of subsidised diesel from 36 diesel fuel depots throughout the country, including 15 depots in Sabah and Sarawak,” he said.

“Since the programme was introduced in 2006, a total of 594 legal cases were filed and 6.86mil litres of diesel seized from those who had abused the diesel fuel subsidy programme,” Ismail said in winding up the debate in his ministry at the committee stage.

It was reported that the Gover nment had suffered losses in terms of subsidies, ranging from RM1bil in 2003 to RM3bil in 2006 before the Nanotag technology was introduced.

On the contract of Teras Kimia Sdn Bhd, which was tasked to carry out the tagging of diesel supplies at fuel depots, Ismail said he was informed that the company’s services would end this year.

“The company had asked for an extension and we are still discussing this with the Finance Ministry,” he added.

Ismail also said the Government had to raise the subsidy payment for sugar due to the increase in global sugar prices. “The Government also wants to reduce the sugar subsidy payments of about RM1bil annually.

“The idea of imposing a uniform price for sugar among Asean countries will help reduce smuggling, but it means that we have to increase the sugar price in Malaysia as it is lower than in other Asean countries.”

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Source: http://thestar.com.my/news/story.asp?file=/2010/4/20/parliament/6087587&sec=parliament

No More Long lines Store Checkout

(NanoRealm) - Long lines at store checkouts could be history if a new technology created in part at Rice University comes to pass.

Rice researchers, in collaboration with a team led by Gyou-jin Cho at Sunchon National University in Korea, have come up with an inexpensive, printable transmitter that can be invisibly embedded in packaging. It would allow a customer to walk a cart full of groceries or other goods past a scanner on the way to the car; the scanner would read all items in the cart at once, total them up and charge the customer's account while adjusting the store's inventory.
More advanced versions could collect all the information about the contents of a store in an instant, letting a retailer know where every package is at any time.

The technology reported in the March issue of the journal IEEE Transactions on Electron Devices is based on a carbon-nanotube-infused ink for ink-jet printers first developed in the Rice lab of James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. The ink is used to make thin-film transistors, a key element in radio-frequency identification (RFID) tags that can be printed on paper or plastic.
"We are going to a society where RFID is a key player," said Cho, a professor of printed electronics engineering at Sunchon, who expects the technology to mature in five years. Cho and his team are developing the electronics as well as the roll-to-roll printing process that, he said, will bring the cost of printing the tags down to a penny apiece and make them ubiquitous.
RFID tags are almost everywhere already. The tiny electronic transmitters are used to identify and track products and farm animals. They're in passports, library books and devices that let drivers pass through tollbooths without digging for change.
The technology behind RFID goes back to the 1940s, when Léon Theremin, inventor of the self-named electronic music instrument heard in so many '50s science fiction and horror movies, came up with a spy tool for the Soviet Union that drew power from and retransmitted radio waves.
RFID itself came into being in the 1970s and has been widely adopted by the Department of Defense and industry to track shipping containers as they make their way around the world, among many other uses.
But RFID tags to date are largely silicon-based. Paper or plastic tags printed as part of a package would cut costs dramatically. Cho expects his roll-to-roll technique, which uses a gravure process rather than ink-jet printers, to replace the bar codes now festooned on just about everything you can buy.


Cho, Tour and their teams reported in the journal a three-step process to print one-bit tags, including the antenna, electrodes and dielectric layers, on plastic foil. Cho's lab is working on 16-bit tags that would hold a more practical amount of information and be printable on paper as well.
Cho came across Tour's inks while spending a sabbatical at Rice in 2005. "Professor Tour first recommended we use single-walled carbon nanotubes for printing thin-film transistors," Cho said.
Tour's lab continues to support the project in an advisory role and occasionally hosts Cho's students. Tour said Rice owns half of the patent, still pending, upon which all of the technology is based. "Gyou-jin has carried the brunt of this, and it's his sole project," Tour said. "We are advisers and we still send him the raw materials" -- the single-walled carbon nanotubes produced at Rice.
Printable RFIDs are practical because they're passive. The tags power up when hit by radio waves at the right frequency and return the information they contain. "If there's no power source, there's no lifetime limit. When they receive the RF signal, they emit," Tour said.

There are several hurdles to commercialization. First, the device must be reduced to the size of a bar code, about a third the size of the one reported in the paper, Tour said. Second, its range must increase.
"Right now, the emitter has to be pretty close to the tags, but it's getting farther all the time," he said. "The practical distance to have it ring up all the items in your shopping cart is a meter. But the ultimate would be to signal and get immediate response back from every item in your store - what's on the shelves, their dates, everything.
"At 300 meters, you're set - you have real-time information on every item in a warehouse. If something falls behind a shelf, you know about it. If a product is about to expire, you know to move it to the front - or to the bargain bin."
Tour allayed concerns about the fate of nanotubes in packaging. "The amount of nanotubes in an RFID tag is probably less than a picogram. That means you can produce one trillion of them from a gram of nanotubes - a miniscule amount. Our HiPco reactor produces a gram of nanotubes an hour, and that would be enough to handle every item in every Walmart.
"In fact, more nanotubes occur naturally in the environment, so it's not even fair to say the risk is minimal. It's infinitesimal."

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More information: Read the paper at: http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5406115
Source: RICE University - http://www.rice.edu/
From PhysOrg.com (http://www.physorg.com/news188129794.html)

(NanoRealm) - A team of scientists has developed a way to control the direction of light on the nanoscale, by developing miniaturized television aerials made from gold nanorods, which can pave the way for quantum computing networks in the future.

At the moment, quantum physicists use cumbersome apparatus to try to keep track of photons, for instance, building large vacuum cavities with mirrored walls to guide light.

"It's funny that to control the small quantum world, you need huge pieces of equipment," said Holger Hofmann, at the Department of Quantum Matter at Hiroshima University in Japan.

Now, according to a report in Nature News, Hofmann and his colleagues have developed a way to control the direction of light on the nanoscale.

Their technique is based on the workings of the 'Yagi-Uda' antenna commonly used to transmit and detect radio waves and often seen on rooftops as television aerials.

Hofmann stumbled on the idea by accident, while teaching his electromagnetism class how antennas work.

"The textbook didn't explain it well, and while trying to come up with my own picture, I realized that the same technique could work on the nanoscale," he said.

A standard Yagi-Uda antenna is made up of a set of parallel metal rods that gradually decrease in length.

An electrical signal is fed into the second longest rod, setting it vibrating and producing a driving electromagnetic wave that spreads out in all directions.

This stimulates the neighbouring rods to oscillate and emit secondary waves.

Both the length and spacing of adjacent rods are carefully set at fractions of the wavelength of the driving wave, so that the secondary waves interfere with the driving wave, amplifying it along the forward direction and reducing it along the sideways and backward directions.

Hofmann and his colleagues realized that gold nanorods should produce the same effect on the nanoscale - but here, the length-to-width ratio of the rods, rather than their length and spacing, is important.

The team etched their mini gold antenna into a glass substrate and drove it directly with red laser light.

The tricky part was to ensure that just one nanorod was driven by the incoming light, just as only one metal rod is in the Yugi-Uda antenna.

To ensure this, the team tilted the chosen nanorod by 45 degrees relative to its neighbours and stimulated it using laser light that was polarized at the same angle.

They then monitored the direction of light transmitted out of the glass substrate.

The result was actually better than their theory predicted, according to Hoffman, with roughly two-thirds of the input light being directed largely forwards. (ANI)

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Provdied by ANI
Souce: Sifynews (http://sify.com/news/nano-antennas-could-pave-way-for-quantum-computing-networks-news-international-kdpn4ddagfc.html)

(NanoRealm) - While scientists have become rather adept at transforming generic skin cells into specialized organ cells, crafting the organs themselves has proven far more difficult. Since the 3-D architecture of most organs is as important to their function as their cellular makeup, 2-D cell cultures are not very useful for building a replacement heart from scratch. To solve that problem, most organ makers create a scaffolding for the cells to grow on.

For a team of researchers at Rice University, even a biodegradable scaffolding wasn't good enough. By injecting cells with a metallic gel, the researchers have succeeded in suspending cultured cells in a three-dimensional magnetic field. With this magnetic scaffolding, organs can be grown in the right shape, and with no foreign material.

The researchers used bacteriophages, special viruses that inject themselves into cells, to insert a polymer iron oxide gel into brain cancer cells. Once the cells absorbed the magnetic gel, the Rice scientists levitated the cells in a weak magnetic field. And since cells naturally live in a 3-D space, not a 2-D culture, the brain cancer cells actually behaved more normally while suspended in the magnetic field then they did when in a cell culture.
The obvious next step involved programming detailed magnetic fields that float stem cells in the exact spots needed for them to grow into a full organ. To that end, the researchers have sold the technology to the company n3D Bioscences. Whether or not this process leaves your replacement organ magnetic, and how that will affect getting through airports, remains to be seen.

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Source: PopSci - http://www.popsci.com/science/article/2010-03/metal-nano-particles-suspend-human-cells-magnetic-scaffolding-organ-manufactoring

(NanoRealm) - Could you imagine a laptop battery that lasted for 500 hours? How about an electric car that boasts a range many times that of a gasoline vehicle? For that matter, think about environmental sensors that could be scattered into the air like dust and collect data. While the last thing might not exactly be what you want for Christmas, a breakthrough in energy production made by MIT researchers could make such technology a reality during the next few years.

The process, dubbed “thermopower waves” by its discoverer, MIT’s Dr. Michael Strano, does nothing less than open up “a new area of energy research, which is rare,” says the scientist. MSNBC’s Michelle Bryner describes the phenomenon and its applications in brief, writing:

Researchers have found a way to produce large amounts of electricity from tiny cylinders made from carbon atoms.

The achievement could replace decades-old methods of generating electricity, such as combustion engines and turbines, the researchers say.

The cylinders are known as “carbon nanotubes,” which are, writes The Energy Collective, “submicroscopic hollow tubes made of a ‘chicken-wire-like’ lattice of carbon atoms.”

To describe the process in more detail, the MIT researchers took the nanotubes, applied a layer of fuel, and then ignited them at one end, creating a “fast-moving thermal [heat] wave traveling along the length of the carbon nanotube like a flame speeding along the length of a lit fuse,” explains the Environment News Service (ENS). This process is facilitated by the fact that nanotubes conduct heat far better than metals — up to 100 times faster. Then, getting more technical still, ENS writes, “As the heat feeds back to the fuel coating, a thermal wave is created that is guided along the nanotube. With a temperature of 3,000 kelvins [sic] (2,726 degrees Celsius or 4,940 degrees Fahrenheit) this ring of heat speads [sic] along the tube 10,000 times faster than the normal spread of this chemical reaction.”

This is where Dr. Strano and his team experienced their Ivory Soap moment. While Strano claims to be the first scientist to predict that thermal waves coursing through a nanotube could create electric current, the great amount of it yielded was not predicted by thermoelectric calculations. “Lo and behold,” said the scientist, “we were really surprised by the size of the resulting voltage peak.” Strano and his team have called this unexpected phenomenon “electron entrainment,” “since part of the current appears to scale with wave velocity,” said Strano.

Because this energy source is so new, it’s hard to predict what the practical applications will be. However, the thermopower-wave process produces 100 times the energy per unit of weight of the average lithium-ion battery. Additionally, Strano says that such a power source would be composed of non-toxic substances, eliminating the disposal problems posed by current-generation energy cells.

The technology could also be used to help create sensors the size of a grain of rice that could be injected into the body and used to monitor health (e.g., heart function), administer medical treatment or, well, use your imagination. There are some ominous implications as well.

One obvious use of the technology, however, would be to create practical electric fuel cells for automobiles. One common drawback of electric cars is that they typically have a very limited range relative to combustion engine vehicles, owing to the fact that gasoline contains far more energy per unit of weight than today’s electric fuel cells. But thermopower-wave generation could change that, providing light, long-range batteries and relatively inexpensive electricity. This could finally allow us to break our dependence on foreign oil.

Whatever the particulars, Dr. Strano’s discovery is just the latest frontier in the staggering field of nanotechnology. The science of manipulating matter on the molecular and even atomic levels, it is quickly making science fiction, science fact.

For more on the subject, see Selwyn Duke's “The New Nanotech World” in the March 31, 2008 issue of The New American.

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Provided by MIT
Source: http://www.thenewamerican.com/index.php/tech-mainmenu-30/energy/3133-nanotech-energy-source-discovered

(NanoRealm) - Researchers at MIT are working on getting computer chips to "self assemble" by coaxing molecules to arrange themselves into tiny but useful patterns, a process that could lead to microprocessors with much smaller circuit elements.

In the journal Nature Nanotechnology this week, the researchers describe a process that could become an alternative to conventional photolithography, which relies on light projected onto a photo-sensitive material, as people continue to forecast the demise of Moore's Law. That observation states that the number of transistors that can be placed on an integrated circuit doubles roughly every two years.
Led by Caroline Ross and Karl Berggren, both engineering professors, the scientists used electron beam lithography to create nanoscale "posts" on a silicon chip. They then deposited copolymers--large molecules of two polymers with repeating structural units--on the chip. The copolymers spontaneously linked to the posts and arranged themselves into useful patterns.
The polymers naturally want to separate from each other, thus causing them to arrange in predictable ways. (Berggren compares compares different polymer molecules to the characters played by Robert De Niro and Charles Grodin in "Midnight Run"--a bounty hunter and a white-collar criminal who are handcuffed together but can't stand each other.)
A variety of patterns that can be used in circuit design could be achieved by changing the shape and position of the posts, the proportions of the polymers, and the length of the molecule chains, MIT said.
When exposed to plasma, one polymer burns away, while the other turns to glass. The latter could work like a photoresist in optical lithography (a photoresist is a light-sensitive material onto which light is projected to form a pattern for the chip).
The team is still working to produce functioning circuits in a prototype chip, and to create even smaller chip features with the copolymer technique.

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Source: CNet (http://news.cnet.com/8301-17938_105-10468870-1.html)

MIT chemical engineer Paula Hammond lends her nanotechnology expertise to farmers in Africa.

(NanoRealm) - Cassava is a tropical root vegetable and staple crop for millions of people in sub-Saharan Africa. However, it’s tricky to handle: Once the root is removed from the ground, it spoils within one to three days, so farmers must get it to processing centers as soon as possible after harvesting it. If they don’t, the crop goes to waste.
A simple way to prolong cassava’s shelf life could help farmers avoid that waste and sell their crop beyond their local region. Paula Hammond, MIT professor of chemical engineering, and other scientists are now working on an innovative way to help them do that, using nanotechnology — technology that controls material at a molecular or atomic scale. Their idea is to design a plastic storage bag lined with nanoparticles that would react with oxygen, preventing the roots’ oxygen-induced rotting.

“That would enable farmers to harvest and store and process at times convenient to them,” says Hammond, who traveled to Kenya and Ghana last summer with an international group of scientists to meet with farmers and come up with new ways to improve agricultural efficiency.

It may seem odd to send Hammond, a chemical engineer who focuses on nanotechnology, into rural Africa to help farmers. But that’s exactly the point, says Todd Barker, a partner for the Meridian Institute, which organized the trip with funding from the Bill & Melinda Gates Foundation.

Organizers were looking for scientists who specialize in fields not traditionally involved in international development. And they wanted people who knew little or nothing about agriculture, says Barker. “We wanted to get them to look at these particular problems in Africa with a fresh set of eyes.”

‘An important problem’

After the Meridian Institute identified three agricultural chains where farmers needed help — cassava, dairy and maize (corn), Barker enlisted Jeffrey Carbeck PhD ’96, a chemical engineer and entrepreneur, to identify scientists who would fit in with the mission. “I was looking for people who had a deep technical background but had shown they could apply it in multiple areas,” says Carbeck, who knew Hammond from their graduate school days at MIT.

Carbeck thought that Hammond, an expert in designing polymers for drug delivery, sensors and energy, would fit perfectly. Hammond, in turn, was intrigued by the idea. “It sounded like such an important problem, and I had never been to Africa. This was a chance to see it from a very unique perspective,” she says.

Equipped with Land Rovers and digital video cameras, the group of a dozen scientists from around the world traveled to farms throughout the two African nations, talking with farmers to find out the biggest obstacles they face.

For Hammond, the trip was enlightening. “These working families have very immediate problems and have neither the resources, nor perhaps the voice, to express them to groups of elite scientists, and that’s what this allowed them to do,” she says. “These are really exciting problems outside the realm of what we might normally encounter in academia.”

The team found that dairy farmers have a similar problem to cassava farmers — getting their milk to processing centers before it spoils. Most farms don’t have their own refrigeration facilities, so the farmers have to carry their milk in plastic jugs, usually on foot or bicycle, to the nearest cooling center.

If the cooling centers are far from the farm, the farmers might make only one trip a day, so any milk produced after that trip is in danger of spoiling before the next day’s trip. Milk that goes bad is rejected at the center and dumped out.

To avoid that waste, Hammond and other scientists in the group came up with the idea to design a milk container with a nanopatterned, antimicrobial coating that would preserve milk longer than a plain plastic jug.

The African dairy farmers are also interested in a way to easily test their cows to see if they’re pregnant or in heat. Cows must be bred and produce calves in order to produce milk, but if a cow runs dry, it’s difficult to tell whether it’s due to lack of pregnancy or a common udder infection known as mastitis.

There is no simple test for cow pregnancy as there is for humans, but scientists who went on the trip came up with the idea to adapt existing nanopatterned paper sensors to detect bovine pregnancy.

The Gates Foundation originally planned to allocate funding for two or three ideas that came out of the trip, but there were so many (more than 200, later consolidated into 22 concepts), that the foundation is encouraging the scientists to pursue as many as possible. The Meridian Institute will initially focus on diagnostic tools for mastitis, the new milk container, tick-borne disease and other livestock diseases, safety tests for milk, a modified plastic tank for maize storage, and a new way to dry cassava.

The Meridian Institute is now working on starting up a foundation that would serve as an “incubator” to help develop, test and bring these ideas to commercialization, according to Barker. “The major challenge now is to make sure the ideas that came out of the trip reach the farmers in Africa,” he says.

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In the World is a column that explores the ways members of the MIT community are developing technology — from the appropriately simple to the cutting edge — to help meet the needs of communities around the planet, especially those in the developing world.

Source: MIT News (http://web.mit.edu/newsoffice/2010/nanotech-farm-0312.html)

(NanoRealm) - A team at Cornell University has developed a technique to permanently coat cotton fibers with electrically conductive nanoparticles. The result makes cotton electronically conductive, while continuing to be lightweight, flexible, and comfortable.

The innovation came from the work of Juan Hinestroza and his colleagues at universities in Bologna and Cagliari, Italy. Dr. Hinestroza, currently an assistant professor of Fiber Science and Apparel Design, earned degrees in chemical and biomolecular engineering from his native country, Columbia, and Tulane University. His research specializes in creating multifunctional fibers by manipulation of nanoscale phenomena.

Focus: Modify, Create and Develop

His work has three focus points: modification of existing textile materials, creation of fibers from polymers, and "development of mathematical models and metrology tools based on scanning probe microscopy to assess nanoscale phenomena on low energy surfaces and high radius of curvature". Nanofibers could be used in, antibacterial, anti-odor, active camouflage and anti-counterfeiting applications. Dr. Hinestroza has worked with magnetic nanoparticles that can create invisible signatures that mints can inscribe on dollar bills.

As to his efforts with textiles, Dr. Hinestroza said. "Previous technologies have achieved conductivity but the resulting fiber becomes rigid and heavy. Our new techniques make our yarns friendly to further processing such as weaving, sewing and knitting."
The science underlying the new cloth is more familiar to readers in the form of conductive inks or pastes of metals such as silver or copper which can be coated onto glass to form an electrically conductive surface. These metal coated glass substrates are used in chips for electronic components. This science is the subject of many patents, included a patent application related to "conductive nanoparticle substrate and method of manufacture" purporting to have "specific qualities that permit the reflow of solder across the surface for the attachment of electrical components, namely high electrical conductivity, good adhesion, scratch resistance."

Combination of Technology and Fashion Became Reality

Combining the technology with cloth will change the future of fabric. Cotton is the vehicle presently. A theme extolling this fiber, The Fabric Of Our Lives, appeared in 1989. Cotton Incorporated, the research and marketing company representing upland cotton even sings its praises in commercials in a song first performed by Richie Havens and later by Aaron Neville.

Cotton Incorporated began a recycling program in 2006 called Cotton - From Blue to Green. They have recycled enough denim to create natural cotton fiber insulation for over 540 homes. Gap stores are participating in a two week drive giving customers who donate denim a 30 percent discount on new denim purchases through March 14. The donated denims will be converted into UltraTouch Natural Cotton Fiber Insulationand donated to needy communities.

Gap brands include Banana Republic and Old Navy. Other retailers who participate in the Cotton - From Blue to Green program include Guess, Vanity and Warner Bros.

Getting back onto the subject of Cornell's University nano-cotton, It will be interesting to tune in to Cornell’s annual Design League Fashion Show, was held on March 13, 2010.

The theme of this year's show is Once Upon A Runway, and show attendants will see the unveiling of a solar-powered dress designed by Hinestroza's student, Abbey Liebman.

Powering your smartphone or MP3 player while on the move couldn’t be easier. The new design uses flexible solar cells which power small electronics from a USB charger in the waist of the dress. The event gives Liebman and other students involved in design, graphics, photography, and theater production an opportunity to showcase their creativity.

Could wearning nano-cotton be the new fashion of the future? We'll leave that for your consideration.

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Source: Bright Side Of News (http://www.brightsideofnews.com/news/2010/3/11/fashion-the-land-of-cotton-is-going-nanotech.aspx)

(NanoRealm) - Thermacore Europe is leading an €8.3m pan-European project called NanoHex, to develop a cutting edge liquid coolant that incorporates purpose engineered nano-particles for more efficient cooling.

Involving 12 European companies and research centres, NanoHex is the world’s largest collaborative nanotechnology project. Its aim is to produce a nanofluid coolant up to 40% more efficient than traditional coolants in order to combat the ever increasing heat loads of high-tech industries.

Nanoparticles Can Play A Role In Cooling

“Studies show that the dispersal of carefully engineered nanoparticles into a fluid significantly aids heat transfer,” said Mamoun Muhammed, Chair Professor at the Royal Institute of Technology Sweden and the Scientific Director NanoHex. ‘And it is this unique property of nanoparticles that NanoHex is looking to harness.’

Cooling is an issue facing many industries such as microelectronics, transportation, manufacturing and power generation. The project seeks to couple significant technical benefit and commercial viability with environmental friendliness, to produce a nanofluid that can be safely manufactured, applied and recycled for use in a diverse range of applications from computers to engines.
“Traditional cooling systems using air or water are not always efficient. They can be expensive to run, produce large carbon footprints and limit productivity.” continued Muhammed. “Nanofluids could help to provide a more economic and efficient cooling system in which the heat may be captured and recycled.”

The three year NanoHex project which began September 1st 2009 received £5.5m from the European Commission’s Framework 7 Programme. Together the 12 strong consortium aims to upscale the manufacturing process to produce large volumes of operational nanofluids in order to take this groundbreaking product to market.

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Provided by NanoHex (http://www.nanohex.eu/)
Source: Nanowerk (http://www.nanowerk.com/news/newsid=15250.php)

(NanoRealm) - For the first time, scientists have succeeded in growing empty particles derived from a plant virus and have made them carry useful chemicals.

The external surface of these nano containers could be decorated with molecules that guide them to where they are needed in the body, before the chemical load is discharged to exert its effect on diseased cells. The containers are particles of the Cowpea mosaic virus, which is ideally suited for designing biomaterial at the nanoscale.

"This is a shot in the arm for all Cowpea mosaic virus technology," says Professor George Lomonossoff of the John Innes Centre, one of the authors on a paper to be published in the specialised nanotechnology scientific journal, Small.
Scientists have previously tried to empty virus particles of their genetic material using irradiation or chemical treatment. Though successful in rendering the particles non-infectious, these methods have not fully emptied the particles.

Scientists at the John Innes Centre, funded by the BBSRC and the John Innes Foundation, discovered they could assemble empty particles from precursors in plants and then extract them to insert chemicals of interest. Scientists at JIC and elsewhere had also previously managed to decorate the surface of virus particles with useful molecules.

"But now we can load them too, creating fancy chemical containers," says lead author Dr Dave Evans.

"This brings a huge change to the whole technology and opens up new areas of research," says Prof Lomonossoff. "We don't really know all the potential applications yet because such particles have not been available before. There is no history of them."
One application could be in cancer treatment. Integrins are molecules that appear on cancer cells. The virus particles could be coated externally with peptides that bind to integrins. This would mean the particles seek out cancer cells to the exclusion of healthy cells. Once bound to the cancer cell, the virus particle would release an anti-cancer agent that has been carried as an internal cargo.

Some current drugs damage healthy cells as well as the cancer, leading to hair loss and other side effects. This technology could deliver the drug in a more targeted way.
"The potential for developing Cowpea mosaic virus as a targeted delivery agent of therapeutics is now a reality," says Dr Evans.

The empty viral particles, their use, and the processes by which they are made, are the subject of a new patent filing. Management of the patent and commercialisation of the technology is being handled by PBL.

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More information: "Cowpea Mosaic Virus Unmodified Empty Virus-Like Particles Can Be Loaded with Metal and Metal Oxide." DOI:10.1002/smll.200902135

Provided by Norwich BioScience Institutes

(NanoRealm) - If harnessing the unlimited solar power of the sun were easy, we wouldn't still have the greenhouse gas problem that results from the use of fossil fuel. And while solar energy systems work moderately well in hot desert climates, they are still inefficient and contribute only a small percentage of the general energy demand. A new solution may be coming from an unexpected source -- a source that may be on your dinner plate tonight.

"Looking at the most complicated membrane structure found in a plant, we deciphered a complex membrane protein structure which is the core of our new proposed model for developing 'green' energy," says structural biologist Prof. Nathan Nelson of Tel Aviv University's Department of Biochemistry. Isolating the minute crystals of the PSI super complex from the pea plant, Prof. Nelson suggests these crystals can be illuminated and used as small battery chargers or form the core of more efficient artificial solar cells.




Nanoscience is the science of small particles of materials and is one of the most important research frontiers in modern technology. In nature, positioning of molecules with sub-nanometer precision is routine, and crucial to the operation of biological complexes such as photosynthetic complexes. Prof. Nelson's research concentrates on this aspect.

The mighty PSI

To generate useful energy, plants have evolved very sophisticated "nano-machinery" which operates with light as its energy source and gives a perfect quantum yield of 100%. Called the Photosystem I (PSI) complex, this complex was isolated from pea leaves, crystalized and its crystal structure determined by Prof. Nelson to high resolution, which enabled him to describe in detail its intricate structure.

"My research aims to come close to achieving the energy production that plants can obtain when converting sun to sugars in their green leaves," explains Prof. Nelson.

Described in 1905 by Albert Einstein, quantum physics and photons explained the basic principles of how light energy works. Once light is absorbed in plant leaves, it energizes an electron which is subsequently used to support a biochemical reaction, like sugar production.

"If we could come even close to how plants are manufacturing their sugar energy, we'd have a breakthrough. It's therefore important to solve the structure of this nano-machine to understand its function," says Prof. Nelson, whose lab is laying the foundations for this possibility.

Since the PSI reaction center is a pigment-protein complex responsible for the photosynthetic conversion of light energy to another form of energy like chemical energy, these reaction centers, thousands of which are precisely packed in the crystals, may be used to convert light energy to electricity and serve as electronic components in a variety of different devices.

"One can imagine our amazement and joy when, upon illumination of those crystals placed on gold covered plates, we were able to generate a voltage of 10 volts. This won't solve our world's energy problem, but this could be assembled in power switches for low-power solar needs, for example," he concludes.

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Adapted from American Friends of Tel Aviv University (http://www.aftau.org/)
Source: Science Daily - http://www.sciencedaily.com/releases/2010/03/100304112237.htm

(NanoRealm) - Consider this T-shirt: It can monitor your heart rate and breathing, analyze your sweat and even cool you off on a hot summer's day. What about a pillow that monitors your brain waves, or a solar-powered dress that can charge your ipod or MP4 player? This is not science fiction - this is cotton in 2010.

Now, the laboratory of Juan Hinestroza, assistant professor of Fiber Science and Apparel Design, has developed cotton threads that can conduct electric current as well as a metal wire can, yet remain light and comfortable enough to give a whole new meaning to multi-use garments. This technology works so well that simple knots in such specially treated thread can complete a circuit - and solar-powered dress with this technology literally woven into its fabric will be featured at the annual Cornell Design League Fashion Show on Saturday, March 13 at Cornell University's Barton Hall.

Using multidisciplinary nanotechnology developed at Cornell in collaboration with the universities at Bologna and Cagliari, Italy, Hinestroza and his colleagues developed a technique to permanently coat cotton fibers with electrically conductive nanoparticles. "We can definitively have sections of a traditional cotton fabric becoming conductive, hence a great myriad of applications can be achieved," Hinestroza said.
"The technology developed by us and our collaborators allows cotton to remain flexible, light and comfortable while being electronically conductive," Hinestroza said. "Previous technologies have achieved conductivity but the resulting fiber becomes rigid and heavy. Our new techniques make our yarns friendly to further processing such as weaving, sewing and knitting."
This technology is beyond the theory stage. Hinestroza's student, Abbey Liebman, was inspired by the technology enough to design a dress that actually uses flexible solar cells to power small electronics from a USB charger located in the waist. The charger can power a smartphone or an MP3 player.

"Instead of conventional wires, we are using our conductive cotton to transmit the electricity -- so our conductive yarns become part of the dress," Hinestroza said. "Cotton used to be called the 'fabric of our lives' but based on these results, we can now call it 'The fabric of our lights.'"

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Provided by Cornell University (http://www.cornell.edu/)
Source: http://www.physorg.com/news187372919.html

(NanoRealm) - Most polymers -- materials made of long, chain-like molecules -- are very good insulators for both heat and electricity. But an MIT team has found a way to transform the most widely used polymer, polyethylene, into a material that conducts heat just as well as most metals, yet remains an electrical insulator.

The new process causes the polymer to conduct heat very efficiently in just one direction, unlike metals, which conduct equally well in all directions. This may make the new material especially useful for applications where it is important to draw heat away from an object, such as a computer processor chip. The work is described in a paper published on March 7 in Nature Materials.

The key to the transformation was getting all the polymer molecules to line up the same way, rather than forming a chaotic tangled mass, as they normally do. The team did that by slowly drawing a polyethylene fiber out of a solution, using the finely controllable cantilever of an atomic force microscope, which they also used to measure the properties of the resulting fiber.
This fiber was about 300 times more thermally conductive than normal polyethylene along the direction of the individual fibers, says the team's leader, Gang Chen, the Carl Richard Soderberg Professor of Power Engineering and director of MIT's Pappalardo Micro and Nano Engineering Laboratories.


The high thermal conductivity could make such fibers useful for dissipating heat in many applications where metals are now used, such as solar hot water collectors, heat exchangers and electronics.

Chen explains that most attempts to create polymers with improved thermal conductivity have focused on adding in other materials, such as carbon nanotubes, but these have achieved only modest increases in conductivity because the interfaces between the two kinds of material tend to add thermal resistance. "The interfaces actually scatter heat, so you don't get much improvement," Chen says. But using this new method, the conductivity was enhanced so much that it was actually better than that of about half of all pure metals, including iron and platinum.
Producing the new fibers, in which the polymer molecules are all aligned instead of jumbled, required a two-stage process, explains graduate student Sheng Shen, the lead author of the paper. The polymer is initially heated and drawn out, then heated again to stretch it further. "Once it solidifies at room temperature, you can't do any large deformation," Shen says, "so we heat it up twice."


Even greater gains are likely to be possible as the technique is improved, says Chen, noting that the results achieved so far already represent the highest thermal conductivity ever seen in any polymer material. Already, the degree of conductivity they produce, if such fibers could be made in quantity, could provide a cheaper alternative to metals used for heat transfer in many applications, especially ones where the directional characteristics would come in handy, such as heat-exchanger fins (like the coils on the back of a refrigerator or in an air conditioner), cell-phone casings or the plastic packaging for computer chips. Other applications might be devised that take advantage of the material's unusual combination of thermal conductivity with light weight, chemical stability and electrical insulation.

So far, the team has just produced individual fibers in a laboratory setting, Chen says, but "we're hoping that down the road, we can scale up to a macro scale," producing whole sheets of material with the same properties.

Ravi Prasher, an engineer at Intel, says that "the quality of the work from Prof. Chen's group has always been phenomenal," and adds that "this is a very significant finding" that could have many applications in electronics. The remaining question, he says, is "how scalable is the manufacturing of these fibers? How easy is it to integrate these fibers in real-world applications?"

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More information: Shen S, Henry A, Tong J, Zheng R, Gang Chen G. Polyethylene nanofibres with very high thermal conductivities. Nature Materials. 7 March 2010.

Provided by Massachusetts Institute of Technology (http://web.mit.edu/)

Source: http://www.physorg.com/news187187249.html

(NanoRealm) - A team of scientists at MIT have discovered a previously unknown phenomenon that can cause powerful waves of energy to shoot through minuscule wires known as carbon nanotubes. The discovery could lead to a new way of producing electricity, the researchers say.

The phenomenon, described as thermopower waves, “opens up a new area of energy research, which is rare,” says Michael Strano, MIT’s Charles and Hilda Roddey Associate Professor of Chemical Engineering, who was the senior author of a paper describing the new findings that appeared in Nature Materials on March 7. The lead author was Wonjoon Choi, a doctoral student in mechanical engineering.

Like a collection of flotsam propelled along the surface by waves traveling across the ocean, it turns out that a thermal wave — a moving pulse of heat — traveling along a microscopic wire can drive electrons along, creating an electrical current.

The key ingredient in the recipe is carbon nanotubes — submicroscopic hollow tubes made of a chicken-wire-like lattice of carbon atoms. These tubes, just a few billionths of a meter (nanometers) in diameter, are part of a family of novel carbon molecules, including buckyballs and graphene sheets, that have been the subject of intensive worldwide research over the last two decades.

A previously unknown phenomenon

In the new experiments, each of these electrically and thermally conductive nanotubes was coated with a layer of a reactive fuel that can produce heat by decomposing. This fuel was then ignited at one end of the nanotube using either a laser beam or a high-voltage spark, and the result was a fast-moving thermal wave traveling along the length of the carbon nanotube like a flame speeding along the length of a lit fuse. Heat from the fuel goes into the nanotube, where it travels thousands of times faster than in the fuel itself. As the heat feeds back to the fuel coating, a thermal wave is created that is guided along the nanotube. With a temperature of 3,000 kelvins, this ring of heat speeds along the tube 10,000 times faster than the normal spread of this chemical reaction. The heating produced by that combustion, it turns out, also pushes electrons along the tube, creating a substantial electrical current.

Combustion waves — like this pulse of heat hurtling along a wire — “have been studied mathematically for more than 100 years,” Strano says, but he was the first to predict that such waves could be guided by a nanotube or nanowire and that this wave of heat could push an electrical current along that wire.

In the group’s initial experiments, Strano says, when they wired up the carbon nanotubes with their fuel coating in order to study the reaction, “lo and behold, we were really surprised by the size of the resulting voltage peak” that propagated along the wire.

After further development, the system now puts out energy, in proportion to its weight, about 100 times greater than an equivalent weight of lithium-ion battery.

The amount of power released, he says, is much greater than that predicted by thermoelectric calculations. While many semiconductor materials can produce an electric potential when heated, through something called the Seebeck effect, that effect is very weak in carbon. “There’s something else happening here,” he says. “We call it electron entrainment, since part of the current appears to scale with wave velocity.”
The thermal wave, he explains, appears to be entraining the electrical charge carriers (either electrons or electron holes) just as an ocean wave can pick up and carry a collection of debris along the surface. This important property is responsible for the high power produced by the system, Strano says.

Exploring possible applications

Because this is such a new discovery, he says, it’s hard to predict exactly what the practical applications will be. But he suggests that one possible application would be in enabling new kinds of ultra-small electronic devices — for example, devices the size of grains of rice, perhaps with sensors or treatment devices that could be injected into the body. Or it could lead to “environmental sensors that could be scattered like dust in the air,” he says.

In theory, he says, such devices could maintain their power indefinitely until used, unlike batteries whose charges leak away gradually as they sit unused. And while the individual nanowires are tiny, Strano suggests that they could be made in large arrays to supply significant amounts of power for larger devices.

The researchers also plan to pursue another aspect of their theory: that by using different kinds of reactive materials for the coating, the wave front could oscillate, thus producing an alternating current. That would open up a variety of possibilities, Strano says, because alternating current is the basis for radio waves such as cell phone transmissions, but present energy-storage systems all produce direct current. “Our theory predicted these oscillations before we began to observe them in our data,” he says.

Also, the present versions of the system have low efficiency, because a great deal of power is being given off as heat and light. The team plans to work on improving that.

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Provided by Massachusetts Institute of Technology (http://web.mit.edu/)
Source: http://www.physorg.com/news187186888.html

Nanotechnology Shows Promise for Use in Treatments for Melanoma, other Skin Conditions

(NanoRealm) - Recent research suggests how the popular skin filler hyaluronic acid works to rejuvenate photoaged skin, and nanotechnology may have potential for use in cosmetic products and topical medical treatments, according to two presentations this week at the annual meeting of the American Academy of Dermatology, held from March 5 to 9 in Miami Beach, Fla.
In one presentation, Dana L. Sachs, M.D., of the University of Michigan in Ann Arbor, presented results of an initial study of six patients showing that hyaluronic acid injections stimulate production of type I collagen, and a subsequent study of 11 patients showing that the mechanism behind this process is increased activity of fibroblasts, which were observed at four and 13 weeks following injection to be in a 'stretched' configuration that correlates with increased collagen production.

In a second presentation, Adnan Nasir, M.D., of the University of North Carolina in Chapel Hill, discussed the pros and cons of nanotechnology and how nanoparticles may someday be used to enhance the effectiveness of cosmetic products such as sunscreens, shampoos and conditioners; anti-aging products such as retinoids, antioxidants, botulinum toxin, and growth factors; and treatments for conditions such as melanoma, atopic dermatitis, and ichthyosis. However, he cautioned that the future of nanotechnology in dermatology depends on the results of an ongoing safety review by the U.S. Food and Drug Administration.

"Research in the area of nanotechnology has increased significantly over the years, and I think there will be considerable growth in this area in the near future," Nasir said in a statement. "The challenge is that a standard has not been set yet to evaluate the safety and efficacy of topical products that contain nanosized particles."

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Source: Modern Medicine (web)
Press Release for:
1) "Research Reveals How Popular Skin Filler Works at the Molecular Level to Stimulate Collagen Production in Sun-Damaged Skin" - Sachs
2) "Sizing Up Nanotechnology: How Nanosized Particles May Affect Skin Care Products" - Nasir

(NanoRealm) - A study published in the American Chemical Society's journal Nano Letters reveals that thermocells based on carbon nanotube electrodes might eventually be used for generating electrical energy from heat discarded by chemical plants, automobiles and solar cell farms.

The research was a joint collaboration between Baratunde Cola, assistant professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech, and an international team of researchers from the U.S., Australia, China, India and the Philippines.
Cola, director of Georgia Tech’s NanoEngineered Systems and Transport Research Group (NEST), described the study as a breakthrough in efficiently harvesting electrical energy from various sources of exhaust or wasted heat.

"Our NEST Lab was fortunate to team with Dr. Ray Baughman's NanoTech Institute at UT Dallas and Dr. Gordon Wallace's Intelligent Polymer Research Institute in Wollongong, Australia, in the final year of a long collaboration that solved key technical problems,” he said. “We brought fresh eyes, as well as our knowledge and experience with heat transfer engineering from the nanoscale to the scale of practical devices to the problem, which provided a key missing link. The team will together work to enable additional breakthroughs that are required for this technology to reach its full commercial potential."

Efficiently harvesting the thermal energy currently wasted in industrial plants or along pipelines could also create local sources of clean energy that in turn could be used to lower costs and shrink an organization’s energy footprint.

The new thermocells use nanotube electrodes that provide a threefold increase in energy conversion efficiency over conventional electrodes.

One of the demonstrated thermocells looks just like the button cell batteries used in watches, calculators and other small electronics. One key difference, however, is that these new thermocells can continuously generate electricity, instead of running down like a battery. The research netted other thermocells, as well, including electrolyte-filled, textile-separated nanotube sheets that can be wrapped around pipes carrying hot waste streams from manufacturing or electrical power plants. The temperature difference between the pipe and its surroundings produces an electrochemical potential difference between the carbon nanotube sheets, which thermocells utilize to generate electricity.

The research team estimates that multi-walled carbon nanotubes in large thermocells could eventually produce power at a cost of about $2.76 per watt from freely available waste energy, compared with a cost of $4.31 per watt for solar cells, which can only be used when the sun is shining. On a smaller scale, button cell-sized thermocells could be used to power sensors or electronic circuits.

The new thermocells take advantage of the exceptional electronic, mechanical, thermal and chemical properties of carbon nanotubes. The nanotubes’ giant surface area and unique electronic structure afforded by their small diameter and nearly one-dimensional structure offer high current densities, which enhance the output of electrical power and the efficiency of energy harvesting.

"Georgians have worked with state support, and in partnership with initiatives such as the Strategic Energy Institute at Georgia Tech, to realize significant gains in renewable energy production,” Cola said. “But to become a leading energy state, we must increasingly explore new ways to extract and utilize all forms of energy. Harvesting waste heat as electricity is one direction our NEST Lab takes with international partners to help provide increased renewable energy options for Georgia and the world."

This research was sponsored by the Office of Naval Research, the National Science Foundation, The Welch Foundation and the Australian Research Council.

Cola recently received the 2009 Defense Advanced Research Projects Agency (DARPA) Young Faculty Award for his work on solar energy conversion. As director of the NEST Lab, his research focuses on realizing the benefits of nanoscience in applications related to waste thermal energy harvesting, solar energy conversion, and thermal management of electronics and energy systems.

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Provided by Georgia Institute of Technology
Source: http://www.physorg.com/news186769267.html

(NanoRealm) - Berkeley Lab researchers have found a better way to trap light in photovoltaic cells through the use of vertical arrays of silicon nanowires. This could substantially cut the costs of solar electric power by reducing the quantity and quality of silicon needed for efficient solar panels.

Solar cells made from silicon are projected to be a prominent factor in future renewable green energy equations, but so far the promise has far exceeded the reality. While there are now silicon photovoltaics that can convert sunlight into electricity at impressive 20 percent efficiencies, the cost of this solar power is prohibitive for large-scale use. Researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab), however, are developing a new approach that could substantially reduce these costs. The key to their success is a better way of trapping sunlight.



“Through the fabrication of thin films from ordered arrays of vertical silicon nanowires we’ve been able to increase the light-trapping in our solar cells by a factor of 73,” says chemist Peidong Yang, who led this research. “Since the fabrication technique behind this extraordinary light-trapping enhancement is a relatively simple and scalable aqueous chemistry process, we believe our approach represents an economically viable path toward high-efficiency, low-cost thin-film solar cells.”

Yang holds joint appointments with Berkeley Lab’s Materials Sciences Division, and the University of California Berkeley’s Chemistry Department. He is a leading authority on semiconductor nanowires - one-dimensional strips of materials whose width measures only one-thousandth that of a human hair but whose length may stretch several microns.

“Typical solar cells are made from very expensive ultrapure single crystal silicon wafers that require about 100 micrometers of thickness to absorb most of the solar light, whereas our radial geometry enables us to effectively trap light with nanowire arrays fabricated from silicon films that are only about eight micrometers thick,” he says. “Furthermore, our approach should in principle allow us to use metallurgical grade or “dirty” silicon rather than the ultrapure silicon crystals now required, which should cut costs even further.”

Yang has described this research in a paper published in the journal Nano Letters, which he co-authored with Erik Garnett, a chemist who was then a member of Yang’s research group. The paper is titled “Light Trapping in Silicon Nanowire Solar Cells.”

Generating Electricity from Sunlight

At the heart of all solar cells are two separate layers of material, one with an abundance of electrons that functions as a negative pole, and one with an abundance of electron holes (positively-charged energy spaces) that functions as a positive pole. When photons from the sun are absorbed, their energy is used to create electron-hole pairs, which are then separated at the interface between the two layers and collected as electricity.



Because of its superior photo-electronic properties, silicon remains the photovoltaic semiconductor of choice but rising demand has inflated the price of the raw material.

Furthermore, because of the high-level of crystal purification required, even the fabrication of the simplest silicon-based solar cell is a complex, energy-intensive and costly process.

Yang and his group are able to reduce both the quantity and the quality requirements for silicon by using vertical arrays of nanostructured radial p-n junctions rather than conventional planar p-n junctions. In a radial p-n junction, a layer of n-type silicon forms a shell around a p-type silicon nanowire core. As a result, photo-excited electrons and holes travel much shorter distances to electrodes, eliminating a charge-carrier bottleneck that often arises in a typical silicon solar cell. The radial geometry array also, as photocurrent and optical transmission measurements by Yang and Garrett revealed, greatly improves light trapping.

“Since each individual nanowire in the array has a p-n junction, each acts as an individual solar cell,” Yang says. “By adjusting the length of the nanowires in our arrays, we can increase their light-trapping path length.”

While the conversion efficiency of these solar nanowires was only about five to six percent, Yang says this efficiency was achieved with little effort put into surface passivation, antireflection, and other efficiency-increasing modifications.

“With further improvements, most importantly in surface passivation, we think it is possible to push the efficiency to above 10 percent,” Yang says.

Combining a 10 percent or better conversion efficiency with the greatly reduced quantities of starting silicon material and the ability to use metallurgical grade silicon, should make the use of silicon nanowires an attractive candidate for large-scale development.

As an added plus Yang says, “Our technique can be used in existing solar panel manufacturing processes.”

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Provided by: Provided by Lawrence Berkeley National Laboratory (http://www.lbl.gov/)
Source: http://www.physorg.com/news186850199.html