Monday, May 22, 2006

Sensors Without Batteries

In the future, the environment could be pervaded by sensors using the same power-scavenging techniques as RFID tags.
By Kate Greene
Some technologists believe that in the future, seemingly invisible computers will be embedded everywhere, collecting data about the environment and making it useful to decision makers. One way to achieve this sort of ubiquitous computing is to disperse tiny sensors that measure, for instance, light, temperature, or motion.
But without a persistent power source, such sensors would need their batteries replaced every few months. In other words, ubiquitous sensors could also mean "ubiquitous dead batteries," says Josh Smith, a researcher at Intel Research in Seattle.
Smith and his team are addressing this problem not by working on longer-lasting batteries but by trying to eliminate the need for batteries altogether. Instead, their prototype devices employ the same power-scavenging technique used by battery-free radio frequency identification (RFID) tags.
The concept of throwing out the sensor battery is not new. Researchers have proposed capturing energy from environmental vibrations or ambient light to power a sensor (see "Free Electricity from Nano Generators"). But it is unclear whether technology that captures ambient energy can be inexpensively integrated into a sensing device.
By contrast, the technology used in RFID tags, which transmit a few bits of information when scanned by an RFID reader, is cheap enough to integrate into sensors and be mass produced; they're already widely used to track livestock and cargo, as well as cars passing through "easy pass" lanes on highways.
Smith explains that Intel's sensor devices use off-the-shelf components: an antenna to send and receive data and collect energy from a reader, and a sensor-containing microcontroller -- a tiny computer that requires only a couple hundred microwatts of power to collect and process data.
The antenna harvests this power directly from the radio waves emitted by an RFID reader. When a tag comes within range of a reader, the reader's radio signal passes through the antenna, generating a voltage that activates the tag. The tag is then able to send information to the reader through a process called backscattering, in which the antenna essentially reflects a data-encoded variation of the received radio signal.
The microcontroller that Smith's team added to the RFID antenna includes a 16-bit microprocessor, 8 kilobytes of flash storage, and 256 bytes of random-access memory.
One of the microcontroller's main jobs is to ensure that information is transmitted to the reader error-free, which requires more computation than a conventional RFID tag can handle. In a typical tag, the error-checking information is precomputed and stored on the chip; but for a sensor, Smith says, this information needs to be computed in real-time as data is gathered.
Just like RFID tags, the battery-free sensors turn on only when they encounter a reader. As long as the RFID reader is within range of the device, Smith says, it can collect data and send it to the reader.
Battery-free sensors could be useful in many areas, including medicine, says Zeke Mejia, chief technology officer of St. Paul-based Digital Angel, an RFID tag maker. They could "check the status and certain conditions in the body" at any moment, Mejia says, from glucose levels in people with diabetes to the pH of blood and other body fluids.
In their current form, Intel's sensors need to be within about a meter of a reader to be activated. That's closer than would be ideal for some applications, such as measuring the temperature of foods packed in large crates or vibrations in thick walls. The problem is that while the microcontroller needs only a milliwatt of power to run, it needs three volts of electricity to turn on, and the sensor has to be within a meter of an industry-standard RFID reader to generate that much energy. But with minor changes to the way the microcontroller processes data, Smith says, the group could reduce the voltage requirement to 1.8 volts, thus extending the range to about five meters.
The team's latest prototype incorporates a light sensor, temperature sensor, and even a tilt sensor into one battery-free device. The researchers are working on ways to integrate the microcontroller and antenna into a single chip that would be easier to install in the field. In the meantime, they have developed a visual demonstration of just how much energy an RFID antenna can garner from a reader: they've used it to power the second hand on a wristwatch.
"It's surprising to people that this invisible form of energy –- radio waves -– can actually make a watch hand move," Smith says. And a single tick of a second hand, Smith says, takes about as much energy as sending one bit of data from his sensor.

Friday, May 19, 2006

Robot carries out operation by itself

MILAN, Italy, May 18 (UPI) -- For the first time, a robot surgeon in Italy has carried out a long-distance heart operation by itself.
"This operation has enabled us to cross a new frontier," said Carlo Pappone, who initiated and monitored the surgery on a PC in Boston, ANSA reported. Pappone is head of Arrhythmia and Cardiac Electrophysiology at Milan's San Raffaele University.
The 50-minute surgery, which took place in a Milan hospital, was carried out on a 34-year-old patient suffering from atrial fibrillation. Dozens of heart specialists attending an international congress on arrhythmia in Boston also watched.
Pappone has used the robot surgeon in at least 40 operations.
"It has learned to do the job thanks to experience gathered from operations on 10,000 patients," Pappone said, pointing out that the robot carries the expertise of several human surgeons used to boost its software.

Monday, May 15, 2006

Organizing dumbbells for nanotech devices

A team of chemists from France, Italy, Spain, the UK, and the US are working together to bridge the gap between nanoscience and nanotechnology. They have now devised a method that could allow them to organize tiny molecular machines on a surface and so build devices that pack in thousands of times as many switching units, for instance, than is possible with a conventional silicon chip.
Chemist Fraser Stoddart, now at the University of California Los Angeles, and his co-workers have designed and made numerous molecules based on hanging ring-shaped molecules on other chain-like molecules and loops. By incorporating functional chemical groups along the length of the chain or around these loops, they have shown that it is possible to make the molecular beads switch between these various functional groups using heat, light, or electricity. The ultimate aim of creating such molecular-scale devices is to use them as switching units or logic gates in a future computer based on molecules instead of silicon chips.

Friday, May 12, 2006

New technology will allow for flexible television and computer screens

Organic light emitting diodes (OLED) are the technology used in making light emitting fabrics used in cell phones and televisions. The fabrication of flexible OLEDs has up to now been held back by the fragility of the brittle indium tin oxide layer that serves as the transparent electrode. But researchers at the Regroupement Québecois sur les Matériaux de Pointe (RQMP) have found a solution which they published in the May online issue of Applied Physics Letters.

"Organic light emitting diodes have in recent years emerged as a promising low cost technology for making large area flat panel displays and flexible light emitting fabrics," explains Richard Martel, professor at the Université de Montréal's chemistry department. "By using carbon nanotubes, a highly conductive and flexible tube shaped carbon nanostructure, thin sheets a few tens of nanometers in thickness can be fabricated following a procedure akin to making paper. These sheets preserve the conductivity and flexibility of the carbon nanotubes and are thin enough to be highly transparent."

By following the fabrication procedure they developed, the researchers succeeded in producing a high-performance OLED on this new electrode material. In their work they also outline the parameters that can be further optimized in order improve the performance of their design. "In addition to their flexibility, carbon nanotube sheets exhibit a number of properties that make them an attractive alternative to transparent conducting oxides for display and lighting applications," says Carla Aguirre, a researcher at the École Polytechnique affiliated with the Université de Montréal. "By applying the appropriate chemical treatment they can in principle be also made to replace the metal electrode in order to make OLEDs that emit light from both sides."

The potential market applications of this technology are many. From rolled-up computer screens to light emitting clothes, this technology will find many uses.

The research Group included: Carla Aguirre and Patrick Desjardins from École Polytechnique, Stéphane Auvray and Richard Martel from Université de Montréal, S. Pigeon from OLA Display Corporation and R. Izquierdo from Université du Québec à Montréal.

Source: University of Montreal

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Thursday, May 11, 2006

For a Bigger Hard-drive, Just Add Water

Imagine having computer memory so dense that a cubic centimeter contains 12.8 million gigabytes of information. Imagine an iPod playing music for 100 millennia without repeating a single song or a USB thumb-drive with room for 32.6 million full-length DVD movies. Now imagine if this could be achieved by combining a computing principle that was popular in the 1960s, a glass of water and wire three-billionths of a meter wide. Science fiction? Not exactly.

Ferroelectric materials possess spontaneous and reversible electric dipole moments. Until recently, it was technologically difficult to stabilize ferroelectricity on the nano-scale. This was because the traditional process of screening the charges was not completely effective. However Jonathan Spanier from Drexel University and his research colleagues have proposed a new and slightly unusual mechanism stabilizing the ferroelectricity in nano-scaled materials: surrounding the charged material with fragments of water.

All ferroelectric materials, even Spanier’s wires that are 100,000 times finer than a human hair, need to be screened to ensure their dipole moments remain stable. Traditionally this was accomplished using metallic electrodes, but Spanier and his team found that molecules such as hydroxyl (OH) ions, which make up water, and organic molecules, such as carboxyl (COOH), work even better than metal electrodes at stabilizing ferroelectricity in nano-scaled materials, proving that sometimes water and electricity do mix.

“It is astonishing to see that molecules enable a wire having a diameter equivalent to fewer than ten atoms to act as a stable and switchable dipole memory element,” said Spanier, an assistant professor of materials science and engineering at Drexel.

If commercialized, ferroelectric memory of this sort could find its way into home computers, rendering traditional hard-drives obsolete. The extreme capacity offered by such a device could easily put a room full of hard-drives and servers into a jacket pocket, but this idea can be applied to other computer components, such as ferroelectric RAM.

RAM is necessary in a computer because it stores information for programs that are currently running. As this news release was written, RAM stored the words in a file. Because RAM can transfer files faster than a hard-drive, it is used to handle running programs. However most RAM is volatile, and if the computer loses power all the information in RAM is lost. This is not the case with ferroelectric memory.

Ferroelectric memory is non-volatile, so it is entirely possible for files to be stored permanently in a computer’s RAM. Applying nano-wires and the new stabilization method to existing ferroelectric RAM would deal a double blow to hard-drives in size and speed.

Spanier and his colleagues, Alexie Kolpak and Andrew Rappe of the University of Pennsylvania and Hongkun Park of Harvard University, are excited about their findings, but say significant challenges lie ahead, including the need to develop ways to assemble the nanowires densely, and to develop a scheme to efficiently write information to and read information from the nanowires. In the interim, Spanier and his colleagues will continue to investigate the role of molecules on ferroelectricity in nanowires and to develop nano-scaled devices that exploit this new-found mechanism.

Source: Drexel University

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Tuesday, May 09, 2006

Wise nano

Just thought I'd give a plug for the wise nano project.

Friday, May 05, 2006

Scientists demonstrate a breakthrough in fabricating molecular electronics

Scientists from Philips Research and the University of Groningen (the Netherlands) have for the first time fabricated arrays of molecular diodes on standard substrates with high yields. The molecular diodes are as thin as one molecule (1.5 nm), and suitable for integration into standard plastic electronics circuits. Based on construction principles known as molecular self-organization, molecular electronics is a promising new approach for manufacturing electronics circuits in addition to today’s conventional semiconductor processing. Details of the technology are presented in the 4 May 2006 issue of Nature.

Although still a relatively new field, molecular electronics can be regarded as the next evolutionary stage for plastic electronics. Molecular electronics holds the potential to fabricate elements for electronics circuits with a functionality that is embedded in just a single layer of molecules.

Instead of using photolithography or printing techniques to etch or print nano-scale circuit features, molecular electronics can be engineered to use organic molecules that spontaneously form the correct structures via self-organization. Nature provides the inspiration by being very efficient at using self-organized structures for conducting charge – e.g. in the photosynthesis in plants and nerve systems in mammals – and assembling such structures with precision beyond the capabilities of any man-made machine or process.

“Molecular electronics will not compete with current silicon-based IC technologies,” explains Dago de Leeuw, a Research Fellow within Philips Research and member of the joint research team that made the breakthrough. “Molecular electronics could be an interesting option for manufacturing plastic electronics. Plastic electronics is very promising for the manufacture of electronics where low temperature or low cost in-line processing techniques are required.”

While there have been many research activities in this field over the last 10 to 20 years, a reliable way of building molecular electronics had not been found. Well-defined molecular-electronics-based diodes can only be realized when the molecules are sandwiched between two metallic (e.g. gold) electrodes. To this end functional molecules are used that (under the proper conditions) spontaneously form a densely-packed monolayer on the bottom electrode. Many approaches have attempted to simply deposit a metal electrode directly on to this monolayer. However, this approach results in shorting, caused by contacts forming between the electrodes, since the monolayer is only 1 to 2-nm thick.

The technology developed by the scientists at the University of Groningen and Philips Research uses monolayers that are confined to predefined holes in a polymer that has been applied on top of the bottom electrode. The key to their success is the deposition of an additional plastic electrode layer on to the monolayer prior to the deposition of the metallic electrode. The plastic electrode protects the monolayer and as such enables a non-detrimental deposition of the gold electrode.

“Based on a molecular self-assembly process we have developed a reliable way to fabricate well-defined molecular diodes,” says Dr Bert de Boer, the Assistant Professor within the Materials Science CentrePlus at the University of Groningen that leads the joint research team. “It will enable us, for the first time, to do reliable and reproducible measurements on molecular junctions, which is essential for the exploration of the potential applications of molecular electronics.”

The success of this research project is further proof of the leading position that the University of Groningen and Philips Research have in plastic electronics research. It also provides a strong foundation to develop new applications for electronic elements in which the functionality has been confined to only one molecular layer.

Source: Philips Research

Carnegie Mellon researchers say use of switchgrass could solve energy woes

Alternative energy solutions
PITTSBURGH-- Carnegie Mellon University researchers say the use of switchgrass could help break U.S. dependence on fossil fuels and curb costly transportation costs.
"Our report indicates the time is right for America to begin a transition to ethanol derived from switchgrass," said Scott Matthews, an assistant professor in the Civil and Environmental Engineering Department. A 25 percent hike in gas prices at the pump since December adds to the researchers' call for more ethanol derived from switchgrass, a perennial tall grass used as forage for livestock. Gasoline prices in the U.S. are approaching an average of $3 a gallon. The Carnegie Mellon findings were published in the May 1 issue of the American Chemical Society's Journal "Environmental Science and Technology."
Matthews, along with W. Michael Griffin, executive director of the Green Design Institute at Carnegie Mellon's Tepper School of Business, and William R. Morrow, a researcher in the university's Department of Civil and Environmental Engineering, said using switchgrass as a supplement to corn to make ethanol would help ensure the availability of large volumes of inexpensive ethanol to fuel distributors and consumers.
"We need to be thinking about how we can make and deliver ethanol once our corn and land resources are maxed out. Switchgrass can be that next step," Griffin said.
The Carnegie Mellon report also found that ethanol derived from the dry, brown switchgrass, a cellulosic ethanol, could be made in sufficient quantities to deliver 16 percent ethanol fuel to all consumers in the U.S. Researchers said this would likely lead to significant decreases and stability in the price of gasoline.
"It's a renewable resource," Griffin said. "Rather than taking a depletable resource from the ground, switchgrass can be grown again and again."
In a recent address, President George W. Bush made a plea for increased focus on renewable energy, mentioning switchgrass by name.
Scientists have long known how to use enzymes and microorganisms to mine the carbon from carbohydrates to make industrial products. But for decades the technology didn't go very far commercially because fossil fuel – hydrocarbon – was a far cheaper carbon source.
Now that oil prices have climbed roughly 35 percent over the past year, cellulosic fermentation technology is becoming economical.
The United Nations Food and Agricultural Organization said last week that biofuels may supply 25 percent of the world's energy needs in 15 to 20 years.
"This shift from using hydrocarbons to carbohydrates could revolutionize many industries, including the nation's huge agricultural sector," Griffin said.
While the Carnegie Mellon researchers think switchgrass can be the source of large volumes of inexpensive ethanol in the future, they are concerned about the potential costs and siting concerns of using pipelines, the most cost-effective way to deliver fuels.
The U.S. has 100,000 miles of pipelines dedicated to transporting petroleum. But Carnegie Mellon researchers say the pipelines can't be efficiently used because impurities from the petroleum would adversely mix with the ethanol. "In the long run, our goal would be to make petroleum pipelines obsolete; which raises questions about whether ethanol pipelines should ever be built," Matthews said.
To avoid potential issues with pipelines, the authors expect regional solutions to dominate, such as widespread adoption of 85 percent ethanol delivered by rail or truck in the Midwest. American automakers already sell flexible-fuel vehicles (that can run on ethanol or gasoline) that can be purchased in the U.S.
Much of the discussions today about alternatives to gasoline, such as hydrogen, have similar issues related to infrastructure. "Unfortunately, most of the research time and money is being spent on the fuels without adequate consideration to how we will get it to consumers cost-effectively," Griffin said.