Swimming Pool Game 'Marco Polo' Used To Develop Robot Control

SOURCE

ScienceDaily (Mar. 25, 2009) — Scientists have used a popular kids swimming pool game to guide their development of a system for controlling moving robots that can autonomously detect and capture other moving targets.

Engineers from Duke University and the University of New Mexico have used the simple pursuit-evasion game "Marco Polo" to solve a complex problem -- namely, how to create a system that allows robots to not only "sense" a moving target, but intercept it.
Such systems have broad applications, ranging from security systems to track unwanted intruders like enemy ships or burglars, to systems that create radiation or environmental hazard maps, or even track endangered species.
The main challenge facing researchers is developing the artificial intelligence to control the robots and their sensors without direct human guidance.
The goal of the game "Marco Polo" is for the person who is "it" to tag another person, who then becomes the new pursuer. However, pursuers must keep their eyes closed. At any time, the pursuer can call out "Marco," and everyone else must respond by saying "Polo." In this way, the pursuer can gradually estimate where the targets are in the pool and where they might go.
"Games give us a good way of making these highly complex problems easier to visualize," said Silvia Ferrari, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering. Ferrari and colleague Rafael Fierro, associate professor of electrical engineering at the University of New Mexico, published the results from their latest experiments online in the Journal on Control and Optimization, a publication of the Society for Industrial and Applied Mathematics.
"Just as in 'Marco Polo,' we needed to create a way that permits mobile robots to detect other moving objects and make predictions about where the targets might go," Ferrari said. "When done efficiently, the mobile sensor switches from pursuit mode to capture mode in the shortest amount of time."
Ferrari's laboratory had already developed a similar type of algorithm, known as cell decomposition, in which space is broken down into a series of distinct cells. Past experiments allowed a robot to move through space without colliding with stationary obstacles.
The latest experiments included not only robots equipped with camera sensors, but also stationary camera sensors, which allowed for "coverage" of all the cells within the space.
"The idea is that multiple sensors are deployed in the space to cooperatively detect moving targets within that space," Fierro said. "As the sensor makes more detections, it is better able to predict the likely path of the intruder. The ultimate path taken by the robot sensor is one that maximizes the probability of detection and minimizes the distance needed to capture the target."
While the security and military applications of this type of detection system are obvious, Fierro also points out that the new algorithms can be used in other ways to detect targets that aren't necessarily intruders.
"Targets could be completely different things, like mines or explosives, or chemical or radiation leaks," Fierro said. "The robots can use their sensors to keep track of the detected locations and build a 'map' to let people know where to go or not to go."
The algorithms could also be used to help explain natural phenomena, such as the behaviors of members of a wolf pack as they chase and capture their prey.
The latest experiments were conducted at the University of New Mexico and involved intruders moving in straight lines at a constant speed.
"We are now developing algorithms that will more closely mimic the real world by giving intruders the ability to take evasive actions," Ferrari said. "The other main issue is to ensure that all the different mobile sensors can communicate with each other at all times and coordinate their activities based on that communication."
The research was supported by the National Science Foundation, Office of Naval Research and U.S. Army Research Office.
Other members of the research team were Duke's Chenghui Cai and Kelli Baumgartner, and Oklahoma State University's James McClintock and Brent Perteet.
Adapted from materials provided by Duke University, Pratt School of Engineering.

New Way To Produce Electronic Components Can Lead To Cheap And Flexible Electronics

SOURCE

ScienceDaily (Mar. 25, 2009) — Flexible display screens and cheap solar cells can become a reality through research and development in organic electronics. Physicists at Umeå University in Sweden have now developed a new and simple method for producing cheap electronic components.

“The method is simple and can therefore be of interest for future mass production of cheap electronics,” says physicist Ludvig Edman.
Organic chemistry is a rapidly expanding research field that promises exciting and important applications such as flexible display screens and cheap solar cells. One attractive feature is that organic electronic materials can be processed from a solution.
“This makes it possible to paint thin films of electronic materials on flexible surfaces like paper or plastic,” explains Ludvig Edman.
Electronic components with various functions can then be created by patterning the film with a specific structure. Until now it has proven to be problematic to carry out this patterning in a simple way without destroying the electronic properties of the organic material.
“We have now developed a method that enables us to create patterns in an efficient and gentle way. With the patterned organic material as a base, we have managed to produce well-functioning transistors,” says Ludvig Edman.
A thin film of an organic electronic material, a so-called fullerene, is first painted on a selected surface. The parts of the film that are to remain in place are directly exposed to laser light. Then the whole film can be developed by rinsing it with a solution. A well-defined pattern then emerges where the laser light hit the surface.
A key advantage with this method of patterning is that it is both simple and scalable, which means that it can be useful in future production of cheap and flexible electronics in an assembly line process.
Other researchers involved in developing the method are Andrzej Dzwilewski and Thomas Wågberg.
The findings are presented in the publication Journal of the American Chemical Society.
Journal reference:
Andrzej Dzwilewski, Thomas Wågberg and Ludvig Edman. Photo-Induced and Resist-Free Imprint Patterning of Fullerene Materials for Use in Functional Electronics. Journal of the American Chemical Society, 2009; 131 (11): 4006 DOI: 10.1021/ja807964x
Adapted from materials provided by Vetenskapsrådet (The Swedish Research Council), via AlphaGalileo.

Nanotech Batteries For A New Energy Future

SOURCE

ScienceDaily (Mar. 20, 2009) — Researchers at the Maryland NanoCenter at the University of Maryland have developed new systems for storing electrical energy derived from alternative sources that are, in some cases, 10 times more efficient than what is commercially available.

In order to save money and energy, many people are purchasing hybrid electric cars or installing solar panels on the roofs of their homes. But both have a problem -- the technology to store the electrical power and energy is inadequate.
Battery systems that fit in cars don't hold enough energy for driving distances, yet take hours to recharge and don't give much power for acceleration. Renewable sources like solar and wind deliver significant power only part time, but devices to store their energy are expensive and too inefficient to deliver enough power for surge demand.
Researchers at the Maryland NanoCenter at the University of Maryland have developed new systems for storing electrical energy derived from alternative sources that are, in some cases, 10 times more efficient than what is commercially available. The results of their research are available in a recent issue of Nature Nanotechnology.
"Renewable energy sources like solar and wind provide time-varying, somewhat unpredictable energy supply, which must be captured and stored as electrical energy until demanded," said Gary Rubloff, director of the University of Maryland's NanoCenter. "Conventional devices to store and deliver electrical energy -- batteries and capacitors -- cannot achieve the needed combination of high energy density, high power, and fast recharge that are essential for our energy future."
Researchers working with Professor Rubloff and his collaborator, Professor Sang Bok Lee, have developed a method to significantly enhance the performance of electrical energy storage devices.
Using new processes central to nanotechnology, they create millions of identical nanostructures with shapes tailored to transport energy as electrons rapidly to and from very large surface areas where they are stored. Materials behave according to physical laws of nature. The Maryland researchers exploit unusual combinations of these behaviors (called self-assembly, self-limiting reaction, and self-alignment) to construct millions -- and ultimately billions -- of tiny, virtually identical nanostructures to receive, store, and deliver electrical energy.
"These devices exploit unique combinations of materials, processes, and structures to optimize both energy and power density -- combinations that, taken together, have real promise for building a viable next-generation technology, and around it, a vital new sector of the tech economy," Rubloff said.
"The goal for electrical energy storage systems is to simultaneously achieve high power and high energy density to enable the devices to hold large amounts of energy, to deliver that energy at high power, and to recharge rapidly (the complement to high power)," he continued.
Electrical energy storage devices fall into three categories. Batteries, particularly lithium ion, store large amounts of energy but cannot provide high power or fast recharge. Electrochemical capacitors (ECCs), also relying on electrochemical phenomena, offer higher power at the price of relatively lower energy density. In contrast, electrostatic capacitors (ESCs) operate by purely physical means, storing charge on the surfaces of two conductors. This makes them capable of high power and fast recharge, but at the price of lower energy density.
The Maryland research team's new devices are electrostatic nanocapacitors which dramatically increase energy storage density of such devices - by a factor of 10 over that of commercially available devices - without sacrificing the high power they traditionally characteristically offer. This advance brings electrostatic devices to a performance level competitive with electrochemical capacitors and introduces a new player into the field of candidates for next-generation electrical energy storage.
Where will these new nanodevices appear? Lee and Rubloff emphasize that they are developing the technology for mass production as layers of devices that could look like thin panels, similar to solar panels or the flat panel displays we see everywhere, manufactured at low cost. Multiple energy storage panels would be stacked together inside a car battery system or solar panel. In the longer run, they foresee the same nanotechnologies providing new energy capture technology (solar, thermoelectric) that could be fully integrated with storage devices in manufacturing.
This advance follows soon after another accomplishment, the dramatic improvement in performance (energy and power) of electrochemical capacitors (ECC's), thus 'supercapacitors,' by Lee's research group, published recently in the Journal of the American Chemical Society. Efforts are under way to achieve comparable advances in energy density of lithium (Li) ion batteries but with much higher power density.
"The University of Maryland's successes are built upon the convergence and collaboration of experts from a wide range of nanoscale science and technology areas with researchers already in the center of energy research," Rubloff said.
The Research Team
Gary Rubloff is Minta Martin Professor of Engineering in the materials science and engineering department and the Institute for Systems Research at the University of Maryland's A. James Clark School of Engineering. Sang Bok Lee is associate professor in the Department of Chemistry and Biochemistry at the College of Chemical and Life Sciences and WCU (World Class University Program) professor at KAIST (Korea Advanced Institute of Science and Technology) in Korea. Lee and Rubloff are part of a larger team developing nanotechnology solutions for energy capture, generation, and storage at Maryland. Their collaborators on electrical energy storage include Maryland professors Michael Fuhrer (physics), associate director of the Maryland Nanocenter Reza Ghodssi (electrical and computer engineering), John Cumings (materials science engineering), Ray Adomaitis (chemical and biomolecular engineering), Oded Rabin (materials science and engineering), Janice Reutt-Robey (chemistry), Robert Walker (chemistry), Chunsheng Wang (chemical and biomolecular engineering), Yu-Huang Wang (chemistry) and Ellen Williams (physics), director of the Materials Research Science and Engineering Center at the University of Maryland.
This work was partially supported by the Laboratory for Physical Sciences and by the university's Materials Research Science and Engineering Center under a grant from the National Science Foundation
Adapted from materials provided by University of Maryland, College Park.

New Organic Material May Speed Internet Access; Telecom Breakthrough Mimics The Settling Snow

SOURCE

ScienceDaily (Mar. 21, 2009) — The next time an overnight snow begins to fall, take two bricks and place them side by side a few inches apart in your yard.

In the morning, the bricks will be covered with snow and barely discernible. The snowflakes will have filled every vacant space between and around the bricks.
What you will see, says Ivan Biaggio, resembles a phenomenon that, when it occurs at the smallest of scales on an integrated optical circuit, could hasten the day when the Internet works at superfast speeds.
Biaggio, an associate professor of physics at Lehigh University, is part of an international team of researchers that has developed an organic material with an unprecedented combination of high optical quality and strong ability to mediate light-light interaction and has engineered the integration of this material with silicon technology so it can be used in optical telecommunication devices.
A description of this material was published on online in the journal Nature Photonics on March 15.
The material, which is composed of small organic molecules with high nonlinear optical susceptibilities, mimics the behavior of the snowflakes covering the bricks when it is deposited into the slot, or gap, that separate silicon waveguides that control the propagation of light beams on an integrated optical circuit.
Just as the snowflakes, being tiny and mobile, fill every empty space between the two bricks, Biaggio says, the molecules completely and homogeneously fill the slot between the waveguides. The slots measure only tens of nanometers wide; 1 nm is one one-billionth of a meter, or about the width of a dozen carbon atoms.
"We have been able to make thin films by combining the molecules into a material that is perfectly transparent, flat, and free of any irregularities that would affect optical properties," says Biaggio.
The slot between the waveguides is the region where most of the light guided by the silicon propagates. By filling the slot, say Biaggio and his collaborators, the molecules add an ultra-fast all-optical switching capability to silicon circuitry, creating a new ability to perform the light-to-light interactions necessary for data processing in all-optical networks.
The nanophotonic device obtained in this way, says the group, has demonstrated the best all-optical demultiplexing rate yet recorded for a silicon-organic-hybrid device.
Multiplexing is the process by which multiple signals or data streams are combined and transmitted on a single channel, thus saving expensive bandwidth. Demultiplexing is the reverse process.
In tests, the novel hybrid device was able to extract every fourth bit of a 170-gigabit-per-second telecommunications data stream and to demultiplex the stream to 42.7 gigabits per second.
Biaggio's group is part of an international collaboration that includes scientists from the Institute of Photonics and Quantum Electronics at the University of Karlsruhe in Germany, the Photonics Research Group at Ghent University in Belgium, and the Laboratory for Organic Chemistry at the Swiss Federal Institute of Technology (ETH) in Zurich. Biaggio is affiliated with Lehigh's Center for Optical Technologies (COT). Another group member, Bweh Esembeson, earned a Ph.D. in physics from Lehigh earlier this year and is now an applications engineer with Thorlabs Inc. in New Jersey.
The silicon-organic-hybrid device and its breakthrough properties were presented for the first time as a postdeadline contribution at a meeting of the optical telecom industry last spring and at several other scientific conferences, and Biaggio's group published an article titled "A High-optical Quality Supramolecular Assembly for Third-order Integrated Nonlinear Optics" in the October 2008 issue of Advanced Materials.
A nonlinear optical answer to bandwidth demand
As Internet users demand greater bandwidth for ever faster communications, scientists and engineers are working to increase the speed at which information can be transmitted and routed along a network. They are hoping to achieve a major leap in velocity by designing circuits that rely solely on light-waves process data.
At present, data must be converted back and forth from optical signals to electrical signals for managing its progress within the optical telecommunication network. This limits the flexibility and the speed of optical telecommunication. All-optical circuits, experts say, could unleash the full potential of optical telecommunication and data processing.
All-optical circuits require nonlinear optical materials with good optical quality. A nonlinear optical response occurs in a material when the intensity of light alters the properties of the material through which light is passing, affecting, in turn, the manner in which the light propagates.
Biaggio's group is working with a small organic molecule called DDMEBT that possesses one of the strongest nonlinear optical responses yet observed when compared to its relatively small size. The molecule can condense from the vapor phase into a bulk material. The high, off-resonant bulk nonlinearity and large-scale homogeneity of this material, says Esembeson, represent a unique combination not often found in an organic material.
"Between high optical nonlinearity in a molecule and ability to actually fabricate a bulk plastic with excellent optical quality, there is always a compromise," he says.
The DDMEBT bulk material possesses 1,000 times the nonlinearity of silica glass. This organic material, however, is difficult to flexibly structure into nanoscale waveguides or other optical circuitry. Silicon, on the other hand, is structurally suited to the dense integration of components on photonic circuit devices. And silicon technology is mature and precise. It enables the creation of waveguides whose nanoscale flatness facilitates the control of light propagation.
"With pure silicon," says Biaggio, "you can build waveguides that enable you to control light beam propagation, but you cannot get ultrafast light-to-light interaction. Using only silicon, people have achieved a data switching rate of only 20 to 30 gigabits per second, and this is very slow.
"We need higher-speed switching to achieve a higher bit rate. Organic materials can do this, but they are not terribly good for building waveguides that control propagation of tightly confined light beams."
To combine the strengths of the DDMEBT and the silicon, Biaggio and his collaborators have fashioned silicon-organic hybrid (SOH) waveguides where silicon waveguides are covered with DDMEBT.
"We have combined the two approaches," he says. "We start from a silicon waveguide designed to guide the light between two silicon ridges . Then we use molecular beam deposition to fill the space between the ridges with the organic material [DDMEBT], creating a dense plastic with high optical quality and high nonlinearity where the light propagates.
"We combine the best of both technologies."
One of the group's singular achievements, he says, is the filling-in process.
"The key question was whether we could put the DDMEBT between the two silicon strips. There is a lot of research in this area, but no one had been able to make an organic material completely and homogeneously cover such a silicon structure, so that it spreads out and fills all the spaces. Homogeneity is necessary to prevent light scattering and losses.
We now achieved this by using a molecular structure that decreases inter-molecular interactions and promotes the formation of a homogeneous solid state. We then heated the molecules to a vapor phase and used a molecular beam to deposit the molecules on top of the silicon structure. The molecules were able to homogeneously fill the nanometer scale slot between the silicon ridges and to cover the whole structure we needed to cover.
"Our collaborators in Karlsruhe, who have state-of-the-art equipment for characterizing optical communications systems, were able to reliably switch individual bits out of a 170 gigabits per second data stream, which is impressive, but the organic material would be able to support even faster data rates"
The researchers summed up their achievements in one of their forthcoming articles: "To the best of our knowledge, this is the first time that nonlinear SOH [silicon-organic hybrid] slot waveguides were used in high-speed optical communication systems. We believe that there is still a large potential for improving the conversion efficiency and the signal quality."
Journal reference:
C. Koos, P. Vorreau, T. Vallaitis, P. Dumon, W. Bogaerts, R. Baets, B. Esembeson, I. Biaggio, T. Michinobu, F. Diederich, W. Freude & J. Leuthold. All-optical high-speed signal processing with silicon–organic hybrid slot waveguides. Nature Photonics, 2009; DOI: 10.1038/nphoton.2009.25
Adapted from materials provided by Lehigh University.

Carbon Nanotubes Are Superior To Metals For Electronics, According to Engineers

SOURCE

ScienceDaily (Mar. 20, 2009) — In the quest to pack ever-smaller electronic devices more densely with integrated circuits, nanotechnology researchers keep running up against some unpleasant truths: higher current density induces electromigration and thermomigration, phenomena that damage metal conductors and produce heat, which leads to premature failure of devices.

But University at Buffalo researchers who study electronics packaging recently made a pleasant discovery: that's not the case with Single-Walled Carbon Nanotubes (SWCNTs).
"Years ago, everyone thought that the problem of cooling for electronics could be solved," said Cemal Basaran, Ph.D., professor in the UB Department of Civil, Structural and Environmental Engineering and director of the Electronics Packaging Lab in UB's School of Engineering and Applied Sciences. "Now we know that's not true. Electronics based on metals have hit a wall. We are done with metals."
Single Walled Carbon Nanotubes are extremely thin, hollow cylinders, measuring no thicker than a single atom. Thousands of times stronger than metals, they are expected to one day replace metals in millions of electronic applications.
Basaran and his doctoral student Tarek Ragab have spent the past four years performing quantum mechanics calculations, which prove that in carbon nanotubes, higher current density does not lead to electromigration and thermomigration; it also produces just one percent of the heat produced by traditional metals, such as copper.
Basaran will present the findings in November when he delivers a keynote lecture at the American Society of Mechanical Engineers (ASME) International Mechanical Engineering Congress and Exposition in Orlando.
The findings demonstrate yet another tantalizing property of CNTs, he said.
"It has been assumed that for carbon nanotubes, the electrical heating process would be governed by Joules law, where resistance in a circuit converts electric energy into heat," said Basaran. "We are the first to show mathematically, from a quantum mechanics point of view, that carbon nanotubes do not follow Joules law."
According to Basaran, this essential difference between metals and carbon nanotubes lies in the way they conduct electricity.
"Even though carbon nanotubes are conductive, they do not have metallic bonds," he said. "As a result, they do not conduct electricity the way that traditional metals do."
In conventional metals, he explained, conduction causes a scattering of electrons within the lattice of the material so that, when electrons move during conduction, they bump into atoms. This creates friction and generates heat, the same way a household iron works.
"On the other hand, in carbon nanotubes, electric conduction happens in a very different, one-dimensional 'ballistic' way," he said. "The electrons are fired straight through the material, so that the electrons have very little interference with the atoms."
He drew an analogy, using the difference between a conventional railroad train and a magnetically levitated train.
"In the conventional train, you have friction between the wheels and the track," said Basaran. "Through the generation of heat, that friction causes a loss of energy. But with a magnetically levitated train, the wheels and track are not in direct contact. Without that friction, they can travel much faster."
The minimal amount of friction gives carbon nanotubes a tremendous advantage over conventional metals, said Basaran. The unique properties of carbon nanotubes will allow engineers to realize a host of smaller, faster and more powerful new devices that right now cannot exist because of the limitations of conventional metals.
"When an electric car finally is manufactured, its batteries probably will be based on carbon nanotubes," said Basaran. "You can't use traditional metals in the engines because they run so hot."
Much of Basaran's $1 million-plus funding at UB comes from sources like the U.S. Navy, which is interested in sophisticated electronics systems that could operate under very demanding conditions, such as the electric ship the Navy is building.
Basaran's unique perspective comes from decades of research, which has fundamentally changed what is known about the high current density performance properties of metals and their limitations.
He also sounded a cautionary note, pointing out that current research and development expenditures on carbon nanotubes in the U.S. electronics industry are very small when compared to those of our Asian competitors.
"If the industry continues this way, when carbon nanotube-based electronics become a reality, U.S. electronics manufacturers may be in a position similar to U.S. car manufacturers today, because they have failed to keep up with advances in engineering," he said.
Adapted from materials provided by University at Buffalo.

Nanoscopic Probes Can Track Down And Attack Cancer Cells

SOURCE

ScienceDaily (Mar. 20, 2009) — A researcher has developed probes that can help pinpoint the location of tumors and might one day be able to directly attack cancer cells.

Joseph Irudayaraj, a Purdue University associate professor of agricultural and biological engineering, developed the nanoscale, multifunctional probes, which have antibodies on board, to search out and attach to cancer cells.
A paper detailing the technology was released last week in the online version of Angewandte Chemie, an international chemistry journal.
"If we have a tumor, these probes should have the ability to latch on to it," Irudayaraj said. "The probe could carry drugs to target, treat as well as reveal cancer cells."
Scientists have developed probes that use gold nanorods or magnetic particles, but Irudayaraj's nanoprobes use both, making them easier to track with different imaging devices as they move toward cancer cells.
The magnetic particles can be traced through the use of an MRI machine, while the gold nanorods are luminescent and can be traced through microscopy, a more sensitive and precise process. Irudayaraj said an MRI is less precise than optical luminescence in tracking the probes, but has the advantage of being able to track them deeper in tissue, expanding the probes' possible applications.
The probes, which are about 1,000 times smaller than the diameter of a human hair, contain the antibody Herceptin, used in treatment of metastatic breast cancer. The probes would be injected into the body through a saline buffering fluid, and the Herceptin would find and attach to protein markers on the surface of cancer cells.
"When the cancer cell expresses a protein marker that is complementary to Herceptin, then it binds to that marker," Irudayaraj said. "We are advancing the technology to add other drugs that can be delivered by the probes."
Irudayaraj said better tracking of the nanoprobes could allow doctors to pinpoint the location of known tumors and better treat the cancer.
The novel probes were tested in cultured cancer cells. Irudayaraj said the next step would be to run a series of tests in mice models to determine the dose and stability of the probes.
The research was funded through a National Institute of Health grant, as well as by the Purdue Research Foundation. Irudayaraj is head of a biological engineering team that includes postdoctoral researcher Chungang Wang and graduate student Jiji Chen.
Adapted from materials provided by Purdue University.

Fast Camera Shows Even Small Variations In Blood Circulation

SOURCE

ScienceDaily (Mar. 20, 2009) — Burns or other disorders that disrupt the blood flow in tissues will soon be easier to assess thanks to a camera that is capable of imaging blood circulation in real time.

Compared to an earlier version, the new optical perfusion camera (TOPCam) from Twente, the Netherlands, is a significant improvement with regard to speed, so that even small variations in blood circulation are immediately visible. The camera is now ready for clinical application. Researchers of the Institute for Biomedical Technology (BMTI) of the University of Twente are publishing an article on the camera in the March number of Optics Express.
After earlier successful tests at the Martini Hospital in Groningen, the Netherlands, the researchers have made a number of significant improvements to the camera. The speed of the earlier version was commended by doctors and nurses, but real-time images of variations in the blood circulation were not yet possible. They are now, though, according to researcher Wiendelt Steenbergen: “We can now see rapid variations in blood circulation, too, for example when the circulation gets going again after occlusion of an arm or after a transplant.” The measured reaction gives an immediate impression of the condition of the vascular bed.
The researchers were able to reach these high speeds by using a broad laser beam to simultaneously illuminate the entire area of skin in question. Images are made of the tissue with a high-speed camera. Laser light that is scattered by moving red blood cells gives variation in the clarity of the pixels as a result of the Doppler Effect. Up till now it had been a problem transferring all the data to the computer quickly enough, but real time images are now enabled by making better use of the camera memory.
Now that the newest modifications have been made, the camera is ready for clinical application, Steenbergen says. The TOPCam is also suitable for other applications such as the assessment of blood circulation in diabetics. This research, which was carried out by the BMTI, was financed by the Technology Foundation (STW).
Journal reference:
Matthijs Draijer, Erwin Hondebrink, Ton van Leeuwen, and Wiendelt Steenbergen. Twente Optical Perfusion Camera: system overview and performance for video rate laser Doppler perfusion imaging. Optics Express, 2009; 17 (5): 3211-3225 DOI: 10.1364/OE.17.003211
Adapted from materials provided by University of Twente.

High-speed Signal Mixer Demonstrates Capabilities Of Transistor Laser

SOURCE

ScienceDaily (Mar. 19, 2009) — Scientists at the University of Illinois have successfully demonstrated a microwave signal mixer made from a tunnel-junction transistor laser. Development of the device brings researchers a big step closer to higher speed electronics and higher performance electrical and optical integrated circuits.

The mixing device accepts two electrical inputs and produces an optical signal that was measured at frequencies of up to 22.7 gigahertz. The frequency range was limited by the bandwidth of the detector employed in the measurements, not by the transistor device.
"In addition to the usual current-modulation capability, the tunnel junction provides an enhanced means for voltage-controlled modulation of the photon output of the transistor laser," said Nick Holonyak Jr., a John Bardeen Chair Professor of Electrical and Computer Engineering and Physics at the U. of I. "This offers new capabilities and a much greater sensitivity for unique signal-mixing and signal-processing applications."
To make the device, the researchers first placed a quantum well inside the base region of a transistor laser. Then they created a tunnel junction within the collector region. They describe the fabrication and operation of the mixing device in the March 13 issue of the journal Applied Physics Letters.
"Within the transistor laser, the tunneling process occurs predominantly through a process called photon-assisted absorption," said Milton Feng, the Holonyak Chair Professor of Electrical and Computer Engineering.
The tunneling process begins in the quantum well, where electrons and holes combine and generate photons, Feng said. Those photons are then reabsorbed to create new pairs of electrons and holes used for voltage modulation.
"The tunnel junction makes it possible to annihilate an electron in the quantum well, and then tunnel an electron out to the collector by the tunnel contact," Feng said.
The transistor output is sensitive to third-terminal voltage control because of the electrons tunneling from the base to the collector, which also creates an efficient supply of holes to the quantum well for recombination.
"This is a new type of transistor," said Holonyak, who also is a professor in the university's Center for Advanced Study, one of the highest forms of campus recognition. "We are using the photon internally to modify the electrical operation and make the transistor itself a different device with additional properties."
High-speed signal mixing, for example, is made possible by the nonlinear coupling of the internal optical field to the base electron-hole recombination, minority carrier emitter-to-collector transport, and the base-to-collector electron tunneling at the collector junction, the researchers report.
The sensitivity of the tunnel-junction transistor laser to voltage control enables the device to be directly modulated by both current and voltage. This flexibility facilitates the design of new nonlinear signal processing devices for improved optical power output.
"The metamorphosis of the transistor is not yet complete," Holonyak said. "We're still working on it, and the transistor is still changing."
Co-authors of the paper are graduate research assistant and lead author Han Wui Then, graduate student Hsin-Yu Wu and senior research scientist Gabriel Walter.
Adapted from materials provided by University of Illinois at Urbana-Champaign.

New Super-bouyant Material: Life Preserver Might Float A Horse

SOURCE

ScienceDaily (Mar. 20, 2009) — Researchers in China are reporting the development of miniature super-bouyant boats that float so well that an ordinary life preserver made from the same material might support a horse without sinking. The advance, they say, might be difficult to apply to full-size craft.

However, it could lead to a new generation of aquatic robots for spy missions and other futuristic devices, the scientists add.
In the new study, Qinmin Pan and Min Wang note that researchers have studied the chemistry of surfaces for years in an effort to design novel drag-reducing and fast-moving aquatic and air devices, such as boats and planes. Scientists have often turned to nature for inspiration. One source: The water strider, whose highly water-repellant (superhydrophobic) legs allow this insect to literally scoot across water surfaces at high speeds. But researchers still have not found a practical way to apply this phenomenon to technology.
Pan and Wang made several miniature boats about the size of a postage stamp. They used copper mesh treated with silver nitrate and other substances to make the boats' surfaces superhydrophobic. When compared to similar copper boats made without the novel surfaces, the water repellant boats floated more smoothly and also showed a surprisingly large loading capacity. The best performing mini-boat floated with up to two times its maximum projected loading-capacity, the scientists say. "Interestingly, the boat is able to keep floating even if its upper edges are below the water surface," the scientists note.
Journal reference:
Qinmin Pan and Min Wang. Miniature Boats with Striking Loading Capacity Fabricated from Superhydrophobic Copper Meshes. Applied Materials & Interfaces, 2009, 1 (2), pp 420-423, 2013423 DOI: 10.1021/am800116d
Adapted from materials provided by American Chemical Society.

Interaction Between Supersonic Fuel Spray And Its Shock Wave Revealed

SOURCE

ScienceDaily (Mar. 19, 2009) — Shock waves are a well tested phenomenon on a large scale, but scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory and their collaborators from Wayne State University and Cornell University have made a breakthrough that reveals the interaction between shockwaves created by high-pressure supersonic fuel jets.

Shockwaves have been studied in the past by such methods as solid impacts and shock generators, but the high-pressure liquid jets created by micrometer sized nozzles can also reach supersonic speeds.
"Shock waves occur in nature and have been studied for many years, but it has been difficult to examine the internal structure of shock waves created by high-pressure fuel jets," Argonne scientist Jin Wang said. "High-intensity X-rays can penetrate the normally opaque jet stream allowing us to see the spray's internal structure and the gaseous environment around the jet, where the shock waves are generated.
Due to the supersonic spray's opaque nature, scientists have been unable to examine the internal structure of these jets and that has limited the improvement of high-pressure and high-speed jets and spray technologies, which are essential for numerous industrial and consumer applications, such as fuel combustions in engines, paint sprays, and industrial sprays. Using high-intensity X-rays created by the Advanced Photon Source and the Cornell High Energy Synchrotron Source at Cornell University, the scientists were able to examine the interaction between the shockwaves and liquid jets with a time resolution of one-millionth of a second. The scientists made the breakthrough by also developing a complex fluid dynamics simulation to understand the experimental observation of such a dynamical event.
In the case of fuel sprays for a combustion engine, such a transient interaction can affect fuel breakup and thus combustion efficiency and emissions. Researchers have quantitatively characterized the dynamic behaviors of the shock waves and shown that this combined experimental and computational approach can be applied to the fluid dynamics of many other systems including shock-wave-induced microbubble jetting, primary breakup modeling and cavitating flows.
The unique insights provided by the simulations were validated with time-resolved x-radiograph experiments. Because understanding the complex multiphase flow occurring in shock wave/fuel jet is extremely difficult, the agreement shown between the multiphase simulations and the experimental data provides an understanding of jet-gas interactions that has not been possible.
The researchers' discoveries may lead to cleaner and more efficient internal combustion engines as well as advances in high-speed jet cleaning, machining and mining.
A research article reporting this study can be seen in Physical Review Letters.
Adapted from materials provided by DOE/Argonne National Laboratory.

Device Provides Household Energy Savings of 12%

SOURCE

ScienceDaily (Mar. 18, 2009) — A team of researchers from the UPC Center for Technological Innovation in Static Converters and Actuators (CITCEA-UPC) has designed the device "100% Off," which disconnects electronic appliances in stand-by mode and reduces their power consumption to zero. The device is compatible with all existing appliances, and the technology is adaptable to other equipment manufactured in the future.

Over the course of a year, the relative cost of running an appliance is higher in stand-by than when it is switched on, as it spends more time in stand-by mode. According to a study carried out by the European Commission in 2005, household appliances in stand-by mode consume 50 TWh (terawatt-hours) per year in the EU alone. This figure, which is equivalent to the annual consumption of a country like Greece or Portugal, represents a total energy cost of 7000 million euros per year and the emission of 20 million tons of CO2.
100% Off will provide household energy savings of 12% by automatically overriding stand-by mode and switching appliances off. In Spain, where the average household spends €367 per year on electricity (according to the latest National Energy Commission report), the elimination of stand-by mode would represent an annual saving of €44.
The system, patented and marketed by the Madrid-based company Good For You, Good for the Planet, also protects against power surges and extends the useful life of appliances.
The device stems from a research project aimed at improving household energy efficiency by controlling the power consumption of individual appliances. This led to the development of a microprocessor that measures the current consumed by an appliance to detect when it is in stand-by mode and switch it off.
100% Off contains an 8-bit microprocessor programmed to run a mathematical algorithm that identifies power modes by measuring the current consumed during normal operation and in stand-by. Miquel Teixidó, a UPC researcher and director of the project, explained that the benefits of this innovation will also be felt outside the home, as it could potentially lower total residential electricity consumption by between 10 and 20% and reduce CO2 emissions by 1%.
The 100% Off device is a power strip for connecting multiple appliances, some of which can be switched off while others are left in stand-by mode. The device has a green button for switching appliances back on when required.
The system can be integrated into new household appliances, and in the future, 100% Off technology will be compatible with a range of devices, such as laser printers which need to switch between stand-by and off modes.
Adapted from materials provided by Universitat Politècnica de Catalunya.

Slimmer, Stickier Nanorods Give Boost To 3-D Computer Chips

SOURCE

ScienceDaily (Mar. 17, 2009) — Researchers at Rensselaer Polytechnic Institute have developed a new technique for growing slimmer copper nanorods, a key step for advancing integrated 3-D chip technology.

These thinner copper nanorods fuse together, or anneal, at about 300 degrees Celsius. This relatively low annealing temperature could make the nanorods ideal for use in heat-sensitive nanoelectronics, particularly for “gluing” together the stacked components of 3-D computer chips.
“When fabricating and assembling 3-D chips, and when bonding the silicon wafers together, you want as low a temperature as possible,” said Pei-I Wang, research associate at Rensselaer’s Center for Integrated Electronics. “Slimmer nanorods, by virtue of their smaller diameters, require less heat to anneal. These lower temperatures won’t damage or degrade the delicate semiconductors. The end result is a less expensive, more reliable device.”
Experimental 3-D computer chips are comprised of several layers of stacked components. Wang said these layers can be coated with thin nanorods, and then heated up to 300 degrees Celsius. Around that temperature, the thin nanorods anneal, turn into a continuous thin film, and fuse the layers together. This study was the first demonstration of slimmer nanorods enabling wafer bonding, according to Wang.
Fundamental research concerning the slimmer nanorods was led by Toh-Ming Lu, the R.P. Baker Distinguished Professor of Physics at Rensselaer. Results of the study were recently published in the journal Nanotechnology.
Research into wafer bonding and incorporating the slimmer nanorods into 3-D integrated computer chips was led by James Jian-Qiang Lu, associate professor in the Department of Electrical, Computer, and Systems Engineering (ECSE) and the Center for Integrated Electronics (CIE) at Rensselaer. Results of the study were recently published in the journal Electrochemical and Solid-State Letters.
The slimmer copper nanorods were formed by periodically interrupting the growth process. The vapor-deposition process was occasionally halted, and the fledgling nanorods were exposed to oxygen. This resulted in a forest of nanorods with diameters between 10 nanometers and 50 nanometers – far smaller than the typical 100-nanometer diameter copper nanorods grown conventionally without interruption.
Vast forests, or arrays, of copper nanorods are produced by vapor deposition at an oblique angle. In a conventional setting, with an uninterrupted stream of copper atoms deposited in a vacuum onto a substrate, the deposition angle naturally results in taller, thicker nanorods.
Periodically interrupting the deposition, and exposing the copper nanorods to ambient air, however, leads to oxygen being absorbed into the surface of the nanorods. During subsequent depositions, this oxidized copper helps to prevent the vaporized copper atoms from migrating away from the very tips of the nanorods. This ensures the nanorods grow taller, without necessarily growing in diameter. The more growth interruptions, the thinner the resulting nanorods, Wang said.
Wang and the research group have filed for a patent for this new technology. The patent is currently pending.
Along with Wang and Toh-Ming Lu, co-authors of the Nanotechnology paper include Gwo Ching Wang, professor and chair of the Department of Physics, Applied Physics, and Astronomy at Rensselaer; Rensselaer physics graduate student Thomas C. Parker; and Tansel Karabacak, assistant professor in the Department of Applied Science at the University of Arkansas at Little Rock.
Co-authors of the Electrochemical and Solid-State Letters paper include Pei-I Wang, Toh-Ming Lu, James Jian-Qiang Lu, Parker, Karabacak, along with Rensselaer research associate Sang Hwui Lee, and Rensselaer Center for Integrated Electronics Senior Applications Engineer Michael D. Frey.
Funding for the research reported in the Electrochemical and Solid-State Letters was provided by the New York State Foundation for Science, Technology and Innovation (NYSTAR) through the Interconnect Focus Center-New York.
Journal reference:
Pei-I Wang, Sang Hwui Lee, Thomas C. Parker, Michael D. Frey, Tansel Karabacak, Jian-Qiang Lu, and Toh-Ming Lu. Low Temperature Wafer Bonding by Copper Nanorod Array. Electrochemical and Solid-State Letters, 2009; 12 (4): H138 DOI: 10.1149/1.3075900
Adapted from materials provided by Rensselaer Polytechnic Institute.

Vigilant Windows Know The Difference Between A Would-be Robber And A Neighborhood Cat

SOURCE

ScienceDaily (Mar. 17, 2009) — It is 6 p.m. and the museum is closing down for the night. The building’s alarm system is switched on and the security guard does his rounds. A novel motion sensor developed by the Fraunhofer Institutes for Applied Polymer Research IAP in Potsdam-Golm and for Computer Architecture and Software Technology FIRST in Berlin could provide even more security in future, enabling window panes and glass doors to detect movements thanks to a special coating.

If anything changes in front of the pane, or someone sneaks up to it, an alarm signal is sent to the security guard.
“The glass is coated with a fluorescent material,” explains IAP group manager Dr. Burkhard Elling. “The coating contains nanoparticles that convert light into fluorescent radiation.” The principle is as follows: The invisible light of a UV lamp “illuminates” the window panes and generates fluorescent radiation in the coating. This radiation is channeled to the edges of the window, where it is detected by sensors. Simple applications require only one sensor. Similarly to a light barrier, if someone steps into the light of the lamp less light reaches the coating and less fluorescent radiation is produced. If several sensors are installed on all four sides of the window frame, conclusions can be drawn from the data as to how fast and in what direction an object is moving. Its size, too, can be estimated by the sensors. Is it a small creature such as a bird or is it a person? The threshold for the alarm can be set, so that moving objects the size of birds for instance do not trigger an alarm.
Likewise, the sensors do not react to light from passing cars, as the researchers at FIRST have developed a software application that can interpret different light signals. This enables the system to easily distinguish between the frequency of the UV lamp and the slowly changing light from a passing headlight. The system has further advantages: it does not infringe on anybody’s personal rights, as it only detects the change in radiation, and not who triggered it. It is also cost-efficient, because the coating can be sprayed onto the windows by airbrush or glued on as a film. A demonstrator system already exists, and the researchers now plan to optimize the dyes and their concentration in the coating.
Adapted from materials provided by Fraunhofer-Gesellschaft, via AlphaGalileo.

Augmented Reality Under Water

SOURCE

ScienceDaily (Mar. 17, 2009) — The Fraunhofer Institute for Applied Information Technology FIT just presented an Augmented Reality system for use under water. A diver's mask with a special display lets the diver see his or her real submarine surroundings overlaid with computer-generated virtual scenes.

In the pilot application, an AR game, the player sees a coral reef with shoals, mussels and weeds, instead of a plain indoor pool. Applications for professional divers are being investigated.
Augmented Reality research has made enormous progress in the last few years, creating many exciting, albeit land-based applications. Now, FIT researchers are the first to demonstrate an AR application designed for underwater use. Submerged use is a major challenge for technical systems. They must be waterproof and robust enough to withstand the high additional pressure of increasing diving depth.
FIT researchers built a prototype AR system that meets these requirements. Its main component is a waterproof display in front of a diver's mask. The display lets the diver see his or her real underwater environment plus additional virtual objects. Thus, a run-of-the-mill indoor pool may be visually upgraded to a (virtual) coral reef with shoals, mussels and weeds. An ultra-mobile PC (UMPC), which the diver takes with him in a backpack, detects underwater markers in the video stream from a camera on the top of the diver's mask. Based on the pictures from the camera and on the data from inertial and magnetic field tracking of the diver's orientation, the system generates visually correct representations of the virtual 3D scenes.
As a demonstrator Fraunhofer FIT created the world's first mobile underwater AR game. It puts the diver in the role of an underwater archaeologist searching for a treasure chest. The playground consists of six virtual 'islands' on the sea bed, each with its specific rich marine wildlife. In one of the underwater locations the treasure chest can be found, but it then takes a code number to open the lock. The elements of this number can be found in 'magical' mussels that hide in the other five locations.
The user interface of this novel underwater game is highly intuitive and optimized for the swimming and diving player: It works without any manual interaction devices.
"For the player, our game combines the fascinating sensation of weightlessness under water with the fascination of advanced AR technology, creating a unique exciting experience that may become a new special attraction for water parks," explains Ms. Lisa Blum, one of the researchers involved in Fraunhofer FIT's research on Collaborative Virtual and Augmented Environments. At the same time, the prototype is a robust platform for development work well beyond entertainment applications. Next Fraunhofer FIT studies potential uses of the submarine AR technology to support professional divers, e. g. in the maintenance of bridges, offshore oil rigs or dams.
Adapted from materials provided by Fraunhofer-Institut fuer Angewandte Informationstechnik (FIT).

Ultra-thin Chip Embedding For Wearable Electronics

SOURCE

ScienceDaily (Mar. 17, 2009) — At the Smart Systems Integration Conference in Brussels (Belgium)*, technologists from IMEC and its associated laboratory at Ghent University present a new 3D integration process enabling flexible electronic systems with a thickness of less than 60 micrometer.

This ultra-thin chip package (UTCP) technology allows integrating complete systems in a conventional low-cost flex substrate. This paves the way to low-cost, unobtrusive wearable electronics for e.g. wearable health and comfort monitoring.
For the integration, the chip is first thinned down to 25 micron and embedded in a flexible ultra-thin chip package. Next, the package is embedded in a standard double-layer flex printed circuit board (PCB) using standard flex PCB production techniques. After embedding, other components can be mounted above and below the embedded chip, leading to a high-density integration.
The integration process uses UTCP interposers which solve the “Known Good Die” issue by enabling easy testing of the packaged thin dies before embedding. Expensive high-density flexible substrates can be avoided by the fan-out UTCP technology which relaxes the interconnection pitch from 100µm or lower to 300µm or more, compatible with standard flex substrates.
IMEC demonstrates the integration technology with a prototype flexible wireless monitor that measures the heart rate (electrocardiogram or ECG) and muscle activity (electromyogram or EMG). The system consists of an embedded ultra-thin chip for the microcontroller and analog-to-digital convertor, an ultra-low power biopotential amplifier chip and a radio transceiver. By thinning down the chips for UTCP embedding, they become mechanically flexible resulting in an increased flexibility of the complete system, making it unobtrusive and comfortable to wear.
*March 10, 2009
Adapted from materials provided by Interuniversity Microelectronics Centre (IMEC).

UCROA: The Last Japanese female humanoid robot

Industrial Technology Research Institute, Agency Chairman:Hiroyuki Yoshikawa ( "AIST") Division of Intelligent Systems Research - Hirai Shigeru Research Group chairman: Kazita Syuuzi, Humanoid Research Group.

Looks close to human with the form, and gait and behavior is very close to humans, humanoid robots that can interact with humans using speech recognition has been developed. HRP-4C, height 158cm, weight 43kg (including battery), the joint position and dimensions refer to the average value of Japanese young women, who achieved near-human appearance. Walking behavior and body work is working to help the human body works and gait measurement in MOSHONKYAPUCHA, HRP by applying the control technology of two-legged robot has been developed to be, very close to human behavior achieved. Also, based on voice recognition and response operation,現SHITA interaction with real people. HRP-4C, AIST Collaboration project in 2006 was conducted in three-year plan for "industrial revolution AIST Research Initiative (" Initiative AIST ")" for "the development of user-oriented open architecture robot (the "UCROA" a) "as part of development as the main purpose of the application to the entertainment industry are expected to use the system and YO fashion. 2009 March 23, which opened on September 8, "Japan from Tokyo Fashion Week" is scheduled to appear in one of the fashion show. Height: 158cm, weight 43kg (including battery), joint position and dimensions, "the Japanese body 1997-98 Dimensions database" to refer to the average value of young women, has achieved a near-human appearance. In addition, HRP-4C is, HRP-2 has been used by Honda Motor Co., conducted a patent for technology development and inheritance.

Electronic Amplifier Capable Of Functioning In Extreme Temperatures Developed

SOURCE

ScienceDaily (Mar. 16, 2009) — Missions to space require “warm” boxes, which protect electronic circuitry from extreme temperatures and exposure to radiation. Electrical engineering researchers at the University of Arkansas have designed and successfully tested an electronic micro amplifier that can operate directly in the space environment without protection from a warm box.

Capable of functioning with consistency and stability at extreme temperatures – from 125 degrees Celsius to negative 180 degrees Celsius – the new amplifier saves power and space required for electronics circuitry and will also contribute to the development and commercial production of electronics and computer systems that do not require protection in extreme conditions and environments.
“This and several other designs focus on wide-temperature operational characteristics of sensor-based, signal-processing circuits,” said Alan Mantooth, professor of electrical engineering and holder of the Twenty-First Century Endowed Chair in Mixed-Signal IC Design and CAD. “But our device is the first fully differential amplifier circuit designed specifically for extreme temperatures, including temperatures in the cryogenic region. Some of our designs have been tested as fully operational down to 2 Kelvin, or negative 271 degrees Celsius.”
The device, made in a commercially available semiconductor process, has a power supply of 3.3 volts and uses two common-mode feedback circuits to better control the voltage of both the input stage and output stage independently. Using these techniques, the researchers were able to construct an amplifier that provides a large differential gain across both wide frequency and temperature.
In electronics and computer systems, amplifiers are small circuit devices that increase the amplitude of a signal, usually voltage or current. Differential amplifiers are a special type of amplifier that multiplies differences in voltage or current between two inputs by a constant factor. This factor is called differential gain, which is simply the measure of the ability of a circuit to increase the power or amplitude of a signal.
Fully differential amplifiers are used in a variety of electronic systems, including analog-to-digital conversion applications. They are considered a building block in the design and development of integrated electronic circuits and chips.
Under Mantooth’s direction, the researchers – electrical engineering graduate students Kimberly Cornett and Ivonne Escorcia and post-doctorate fellow Guoyuan Fu – developed a device with three distinct sections. The design consisted of an input stage, an output stage and their respective common-mode feedback circuits.
The input stage connects directly to two voltage signals of interest. The difference between the input signals is amplified in the input stage and then further amplified in the output stage. Because only the difference in the two input signals is desired, anything that is similar, or “common,” between the two signals should be cancelled.
Common-mode feedback circuitry ensures that both the input and the output stages are only amplifying the difference of the input signals and cancelling anything that is common between them. Using independent common-mode feedback circuits for input and output stages allows for more fine-tuning and a higher quality output signal.
The research was presented and published March 9 at the IEEE Aerospace Conference in Big Sky, Mont.
Adapted from materials provided by University of Arkansas, Fayetteville.

MIT Battery Material Could Lead To Rapid Recharging Of Many Devices

SOURCE

ScienceDaily (Mar. 16, 2009) — MIT engineers have created a kind of beltway that allows for the rapid transit of electrical energy through a well-known battery material, an advance that could usher in smaller, lighter batteries — for cell phones and other devices — that could recharge in seconds rather than hours.

The work could also allow for the quick recharging of batteries in electric cars, although that particular application would be limited by the amount of power available to a homeowner through the electric grid.
The work, led by Gerbrand Ceder, the Richard P. Simmons Professor of Materials Science and Engineering, is reported in the March 12 issue of Nature. Because the material involved is not new — the researchers have simply changed the way they make it — Ceder believes the work could make it into the marketplace within two to three years.
State-of-the-art lithium rechargeable batteries have very high energy densities — they are good at storing large amounts of charge. The tradeoff is that they have relatively slow power rates — they are sluggish at gaining and discharging that energy. Consider current batteries for electric cars. "They have a lot of energy, so you can drive at 55 mph for a long time, but the power is low. You can't accelerate quickly," Ceder said.
Why the slow power rates? Traditionally, scientists have thought that the lithium ions responsible, along with electrons, for carrying charge across the battery simply move too slowly through the material.
About five years ago, however, Ceder and colleagues made a surprising discovery. Computer calculations of a well-known battery material, lithium iron phosphate, predicted that the material's lithium ions should actually be moving extremely quickly.
"If transport of the lithium ions was so fast, something else had to be the problem," Ceder said.
Further calculations showed that lithium ions can indeed move very quickly into the material but only through tunnels accessed from the surface. If a lithium ion at the surface is directly in front of a tunnel entrance, there's no problem: it proceeds efficiently into the tunnel. But if the ion isn't directly in front, it is prevented from reaching the tunnel entrance because it cannot move to access that entrance.
Ceder and Byoungwoo Kang, a graduate student in materials science and engineering, devised a way around the problem by creating a new surface structure that does allow the lithium ions to move quickly around the outside of the material, much like a beltway around a city. When an ion traveling along this beltway reaches a tunnel, it is instantly diverted into it. Kang is a coauthor of the Nature paper.
Using their new processing technique, the two went on to make a small battery that could be fully charged or discharged in 10 to 20 seconds (it takes six minutes to fully charge or discharge a cell made from the unprocessed material).
Ceder notes that further tests showed that unlike other battery materials, the new material does not degrade as much when repeatedly charged and recharged. This could lead to smaller, lighter batteries, because less material is needed for the same result.
"The ability to charge and discharge batteries in a matter of seconds rather than hours may open up new technological applications and induce lifestyle changes," Ceder and Kang conclude in their Nature paper.
This work was supported by the National Science Foundation through the Materials Research Science and Engineering Centers program and the Batteries for Advanced Transportation Program of the U.S. Department of Energy. It has been licensed by two companies.
Journal reference:
Byoungwoo Kang & Gerbrand Ceder. Battery materials for ultrafast charging and discharging. Nature, 2009; 458 (7235): 190 DOI: 10.1038/nature07853
Adapted from materials provided by Massachusetts Institute of Technology.

Spinning Carbon Nanotubes Spawns New Wireless Applications

SOURCE

ScienceDaily (Mar. 16, 2009) — The University of Cincinnati has long been known for its world-record-breaking carbon nanotubes. Now researchers at the University of Cincinnati have discovered new uses by spinning carbon nanotubes (CNTs) into longer fibers with additional useful properties.

Breakthroughs Without Broken Threads
Taking technology that has already been proven to grow carbon nanotubes of world-record breaking lengths, researchers Vesselin Shanov and Mark Schulz in the UC College of Engineering NanoWorld Lab have now found new applications by spinning these fibers into strong threads.
David Mast, from UC’s McMicken College of Arts and Sciences, saw possibilities in the threads. Mast, an associate professor of physics, took a 25-micron carbon nanotube thread and created a dipole antenna using double-sided transparent tape and silver paste. He was immediately successful in transmitting radio signals.
“It transmitted almost as well as the copper did, but at about one ten-thousandth of the weight,” says Mast.
Mast was able to transmit both AM and FM in his lab, broadcasting a local NPR station.
“Then I decided to dismantle my cell phone,” says Mast. He created a cell phone antenna, using CNT thread and tape. Ripping the back off his own cell phone, he tore out the phone’s original antenna and replaced it with his home-made one. With the “nano-antenna” or "nantenna," he was able to get four to five “bars” of service, compared to none when he removed it.
“That was a very pleasant surprise, how easy it was to do,” Mast says. “The hardest thing is to manipulate them. They float on ambient air.”
From there it was an easy leap to video, in which he was again successful. “I want to now set up a wireless webcam for the lab using these thread antennas so that others can see how well they work.”
Mast says that the key to the new applications is the quality of the material that Schulz and Shanov came up with using multi-wall carbon nanotubes.
“They spin thread that is of such high quality, it opens the door to incredible possibilities,” says Mast. “This is just one of many potential applications.”
Schulz explains that the carbon nanotube threads work well as an antenna because of something called the “skin effect.”
“The electrons transfer well because they want to go to the surface,” he says. “Instead of traveling through a bulk mass, they are traveling across a skin.”
“Copper wire is a bulk material,” Shanov points out. “With carbon nanotubes, all the atoms are on the surface of these carbon structures and the tubes themselves are hollow, so the CNT thread is small and light.”
“Carbon thread that is a fraction of the weight of current copper conductors and antennas could directly apply and would be significant to aerospace activities — commercial, military and space,” he adds. “On any aircraft, there are about several hundred pounds of copper as cables and wiring.”
Mast points out that the threads have what he calls an “immensely high tensile strength — perhaps five times that of steel and yet they are less dense than steel.”
Now that the team has shown the feasibility of such applications, the next steps will be to work on improvements (such as making yarn out of several threads) and to find industries that will commercialize CNT thread.
Mast's next step was going to be to buy a new cell phone. However, he says, "it works so well now that I decided to just upgrade to a new antenna made of carbon nanotube yarn."
This research was funded by the National Science Foundation (with technical monitors Shaochen Chen, Shih-Chi Liu, and K. Jimmy Hsia), and North Carolina A&T SU (collaborators Jag Sankar and Sergey Yarmolenko) through their NSF-ERC (technical monitor Lynn Preston) and ONR-CNN (technical monitor Ignacio Perez) projects.
Adapted from materials provided by University of Cincinnati.

It's All Relative: UC San Diego's Einstein Robot Has 'Emotional Intelligence'

SOURCE

By Tiffany Fox
Albert Einstein may have written his last scientific theory more than half a century ago, but he's still honing his emotional intelligence in a laboratory at the University of California, San Diego.

Scientists at UC San Diego's California Institute for Telecommunications and Information Technology (Calit2) have equipped a robot modeled after the famed theoretical physicist with specialized software that allows it to interact with humans in a relatively natural, conversational way. The so-called "Einstein Robot," which was designed by Hanson Robotics of Dallas, Texas, recognizes a number of human facial expressions and can respond accordingly, making it an unparalleled tool for understanding how both robots and humans perceive emotion, as well as a potential platform for teaching, entertainment, fine arts and even cognitive therapy.
"In the short-term, Einstein is being used to develop computer vision so we can see how computers perceive facial expressions and develop hardware to visually react," says Javier Movellan, a research scientist in the Calit2-based UCSD Machine Perception Laboratory (MPL). "This robot is a scientific instrument that we hope will tell us something about human-robot interaction, but also human-to-human interaction.
"When a robot interacts in a way we feel is human, we can't help but react. Developing a robot like this one teaches us how sensitive we are to biological movement and facial expressions, and when we get it right, it's really astonishing."
The Einstein Robot — a head-and-shoulders automaton complete with unruly white hair and bushy mustache — made its public debut at the Technology, Entertainment and Design (TED) conference in Long Beach last week. David Hanson, the robot's primary designer and owner of Hanson Robotics, amazed a crowd of 1,500 with Einstein's capacity to understand and mimic expressions. Several graduate students from the MPL accompanied Hanson to the conference, which was established to facilitate creative collaborations among scientists, entrepreneurs and designers.

Evoking realistic facial expressions in a machine made of wires and gears is no small feat, Hanson says. For Einstein to crack a smile, 17 of the robot's 31 motors must whir into action and subtly adjust multiple points of articulation around his mouth and piercing brown eyes. To express confusion, Einstein furrows his brow, but even that movement — which is second nature for most humans — is difficult to re-create in a robot. To achieve a realistic result, Hanson constructed Einstein's face from a patented, flesh-like material known as Frubber™, which he created after extensive research into facial anatomy, physiology, materials science and soft-bodied mechanical engineering. Hanson even went so far as to fashion the Frubber™ with realistic pores that measure in the macro-molecular scale at 4 to 40 nanometers — requiring him to take a crash course in nanotechnology.
"I know how the face needs to look when it deforms into a given expression, and I can see when an expression looks good," notes Hanson, a former Disney Imagineer. "But in addition to all these science and engineering studies, there's a certain magic of facial aesthetics that's beyond the scope of scientists. Artists understand it somehow, and are able to externalize facial movements and conversational interaction in external media like sculpture and film animation. However, this has not been successfully imported to robotics. Instead of sculpting it in marble, I have to get the Frubber™ material and the internal mechanisms to move into that expression on demand, and achieve that expression in the context of an interaction with a human."
The robot's internal facial recognition software is what provides that context. Developed by Movellan and a team of graduate students at Calit2, the software is based on a series of computational algorithms derived from an analysis of more than one million facial images. It allows Einstein to understand and respond to a number of "perceptual primitives," such as expressions of sadness, anger, fear, happiness and confusion, as well as facial cues suggesting age and gender (even whether the person interacting with the robot is wearing glasses). The robot's parallel facial action coding system can detect simple gestures like nods, and mimic those reactions.

Movellan, working with Jacobs School of Engineering computer science professor Yoav Freund, also succeeded in getting the robot to respond to audio cues such as clapping, which might prove helpful were Einstein to be used in an educational setting, for example. Movellan says he's hoping to have the robot's operational system fully integrated by June so that it can be deployed as a prototype robot teacher in a local high school, in much the same way that MPL's RUBI robot has been used to teach pre-schoolers.
Another important part of the robot's inner workings is its Character Engine Artificial Intelligence Control Software, which allows the programmer to author and define the persona of the character so it can hold a conversation.
"Einstein has pretty broad conversational abilities, although not like a human," Hanson notes. "In the demo mode, he might say something like, 'I'm an advanced perceptual robot bringing together many technologies into a whole that's greater than the sum of my parts, but here's what some of my parts can do. I can see your facial expressions and mimic them. I can see your age and gender. So why don't we demo some of these technologies?'"
During a demo, Einstein might turn his head, lock eyes with you, and then flash a dashing smile to mimic your own. But as loveable as the robot is, its developers have had to contend with a paradox familiar to all designers of humanoid robots: The more human-like the robot, the creepier it is to actual humans. And that's of crucial importance when one of the primary motivations behind the robot is to get humans to interact with it in a natural way.
"Some scientists believe strongly that very human-like robots are so inherently creepy that people can never get over it and interact with them normally," Hanson says, alluding to Japanese roboticist Masahiro Mori's "uncanny valley theory." Mori's hypothesis speculates that when robots look and act like actual humans, it creates a response of revulsion among human observers. "But these are some of the questions we're trying to address with the Einstein robot," explains Hanson. "Does software engage people more when you have a robot that's more aware of you? Are human-like robots inherently creepy, and if so is that a barrier, or is it not a barrier?
"We're trying to get past the novelty of the technology to a certain extent so that people can socially engage with the robots and get lost in that social engagement," he continues. "And in a sense, we naturally do that with other humans. If I have a big piece of spinach in my teeth or I have something cosmetically atypical about me, it might be difficult to get past those superficial barriers so that we can have a more meaningful conversation."
"As people get more comfortable with them, these robots are becoming more popular," adds Movellan (think Johnny Depp as the "Captain Jack Sparrow" automaton at Disneyland's "Pirates of the Caribbean"). "Although we're thinking of Einstein as a tool for science right now, in the future, I could see it being used in museums or as a way to teach people from other cultures how to interact with one another. You could, in principle, program the robot to interact in a more Japanese way, or a more Middle Eastern way. We're also exploring the use of the robot for children with autism. It could be used as a way to teach them facial expression recognition."
But for now, manufacturing robots like Einstein remains cost-prohibitive.
"This isn't yet a real manufacturing business — these robots are still being built by engineers, so they're still very expensive," Hanson cautions. "Right now it costs $50,000 and up for a robot with very few degrees of freedom; something full-featured like Einstein will cost $75,000 and up. But our aspiration and our core discoveries are targeting mass production and trying to get the robots made for under $200."
All applications and cost factors aside, Hanson and Movellan say their ultimate goal is to develop a creative, intelligent machine that rivals or exceeds a human level of intelligence — and perhaps most importantly — does so without compromising civilization and humanity.
"This is something on the order of an Apollo project or a Manhattan project or a Linux initiative," Hanson explains. "It requires a lot of people at a lot of institutions cooperating and competing with each other to find the best way of creating a complete mind for a robot. If things go really well, we're maybe 10 years away from that happening. But it's very important that we develop empathic machines, machines that have compassion, machines that understand what you're feeling. If these robots do become as intelligent as human beings, we want this infrastructure of compassion and empathy to be in place so the machines are prepared to use their intellectual powers for the good of civilization rather than in ways that undermine the stability of civilization. In a way, we're planting the seeds for the survival of humanity."

Media Contact: Tiffany Fox, 858-246-0353

Spin Battery: Physicist Develops Battery Using New Source Of Energy

SOURCE

ScienceDaily (Mar. 12, 2009) — Researchers at the University of Miami and at the Universities of Tokyo and Tohoku, Japan, have been able to prove the existence of a "spin battery," a battery that is "charged" by applying a large magnetic field to nano-magnets in a device called a magnetic tunnel junction (MTJ).

The new technology is a step towards the creation of computer hard drives with no moving parts, which would be much faster, less expensive and use less energy than current ones. In the future, the new battery could be developed to power cars.
The study is published in the journal Nature and is available online.
The device created by University of Miami Physicist Stewart E. Barnes, of the College of Arts and Sciences and his collaborators can store energy in magnets rather than through chemical reactions. Like a winding up toy car, the spin battery is "wound up" by applying a large magnetic field --no chemistry involved. The device is potentially better than anything found so far, said Barnes.
"We had anticipated the effect, but the device produced a voltage over a hundred times too big and for tens of minutes, rather than for milliseconds as we had expected," Barnes said. "That this was counterintuitive is what lead to our theoretical understanding of what was really going on."
The secret behind this technology is the use of nano-magnets to induce an electromotive force. It uses the same principles as those in a conventional battery, except in a more direct fashion. The energy stored in a battery, be it in an iPod or an electric car, is in the form of chemical energy. When something is turned "on" there is a chemical reaction which occurs and produces an electric current. The new technology converts the magnetic energy directly into electrical energy, without a chemical reaction. The electrical current made in this process is called a spin polarized current and finds use in a new technology called "spintronics."
The new discovery advances our understanding of the way magnets work and its immediate application is to use the MTJs as electronic elements which work in different ways to conventional transistors. Although the actual device has a diameter about that of a human hair and cannot even light up an LED (light-emitting diode--a light source used as electronic component), the energy that might be stored in this way could potentially run a car for miles. The possibilities are endless, Barnes said.
"There are magnets hidden away in many things, for example there are several in a mobile telephone, many in a car, and they are what keeps your refrigerator closed," he said. "There are so many that even a small change in the way we understand of how they work, and which might lead to only a very small improvement in future machines, has a significant financial and energetic impact."
Adapted from materials provided by University of Miami, via EurekAlert!, a service of AAAS.

Autonomous Robot Dancer Identifies Dance And Music In Intelligent Manner

SOURCE

ScienceDaily (Mar. 6, 2009) — Built from a simple Lego NXT kit, a new robotic system designed by a student of FEUP can identify different types of dance and music in an intelligent manner and is fully autonomous. The next step is to create and manage choreography between humanoid robots.

The project started just over a year and is already a successful example of the application of advanced concepts of artificial intelligence. In the final course project, João Oliveira, a student finalist at the Masters in Integrated Electrical Engineering of the Faculty of Engineering of the University of Porto (FEUP), decided to implement in a simple Lego NXT kit a software similar to the one that is developed in robotic soccer.
The result of this combination of mathematical algorithms with a little explored area in the robotic world - music - is now in sight: a robot that applies algorithms to the level of perception of rhythmic musical notes, with an integrated system for intelligent hearing. The whole system of dance is essentially reactive, since the robot reacts in sync with different stimuli (either musical or related to the colour of the dance floor), expressing the movement of dance priori defined by the user.
With the guidance of researchers Luís Paulo Reis (FEUP/LIACC) and Fabien Gouyon (INESC Porto), the next step is to create and manage choreographies between humanoid robots, something that John Oliveira is already doing in its Doctoral Program in Computer Science, funded with a grant from FCT. Despite being in a laboratory phase, this project distinguishes itself, according to this student, "by presenting an application and a modular interface that allows some flexibility and interaction from the user on the behaviour of the robot, defining the movement that it should express home set of stimuli”.
The fact that the robot is built from a simple Lego NXT kit presenting a design for the ad-hoc application of any type of dance, may lead young people to be interested in this issue and decide to build their own robot. With diverse applications in the field of entertainment - there are even competitions for robotics dance, as it exists within the RoboCup Junior - this robot allows students of different ages to create their own dances and records, interacting with interdisciplinary teaching in different areas such as robotics, music, rhythm, dance and movement optimization.
Adapted from materials provided by Faculdade de Engenharia da Universidade do Porto, via AlphaGalileo.

Wag The Robot? Robot Responds To Human Gestures

SOURCE

ScienceDaily (Mar. 11, 2009) — Imagine a day when you turn to your own personal robot, give it a task and then sit down and relax, confident that your robot is doing exactly what you wanted it to do.

So far, that autonomous, do-it-all robot is the stuff of science fiction or cartoons like "The Jetsons." But a Brown University-led robotics team has made an important advance: The group has demonstrated how a robot can follow nonverbal commands from a person in a variety of environments — indoors as well as outside — all without adjusting for lighting.
"We have created a novel system where the robot will follow you at a precise distance, where you don't need to wear special clothing, you don't need to be in a special environment, and you don't need to look backward to track it," said Chad Jenkins, assistant professor of computer science at Brown University and the team's leader.
Jenkins will present the achievement at the Human-Robot Interaction conference March 11-13, 2009, in San Diego. A paper accompanying the video also will be presented at the conference. Matthew Loper, a Brown graduate student, is the lead author on the paper. Contributors include former Brown graduate student Nathan Koenig, now at the University of Southern California; former Brown graduate student Sonia Chernova; and Chris Jones, a researcher with the Massachusetts-based robotics maker iRobot Corp.
A video that shows the robot following gestures and verbal commands can be found in the Brown University release.
In the video, Brown graduate students use a variety of hand-arm signals to instruct the robot, including "follow," "halt," "wait" and "door breach." For much of the time, a student walks with his or her back to the robot, turning corners in narrow hallways and walking briskly in an outdoor parking lot. Throughout, the robot dutifully follows, maintaining an approximate three-foot distance, even backing up when a student turns around and approaches it.
In one sequence, Chernova, now studying at Carnegie-Mellon University, instructs the robot with a series of gestures and verbal commands to move through an open doorway, stop, turn around and then cross the threshold again to return where it had started. Chernova then commands the robot to follow her through the hallway.
The team also successfully instructed the robot to turn around (a 180-degree pivot) and to freeze when the student disappeared from view — essentially idling until the instructor reappeared and gave a nonverbal or verbal command.
The Brown team started with a PackBot, a mechanized platform developed by iRobot that has been used widely by the U.S. military for bomb disposal, among other tasks. The researchers outfitted their robot with a commercial depth-imaging camera (picture the head on the robot in the film Wall-E). They also geared the robot with a laptop that included novel computer programs that enabled the machine to recognize human gestures, decipher them and respond to them.
The researchers made two key advances with their robot. The first involved what scientists call visual recognition. Applied to robots, it means helping them to orient themselves with respect to the objects in a room. "Robots can see things," Jenkins explained, "but recognition remains a challenge."
The team overcame this obstacle by creating a computer program, whereby the robot recognized a human by extracting a silhouette, as if a person were a virtual cutout. This allowed the robot to home in on the human and receive commands without being distracted by other objects in the space.
"It's really being able to say, 'That's a person I'm looking at, I'm going to follow that person,'" Jenkins said.
The second advance involved the depth-imaging camera. The team used a CSEM Swiss Ranger, which uses infrared light to detect objects and to establish distances between the camera and the target object, and, just as important, to measure the distance between the camera and any other objects in the area. The distinction is key, Jenkins explained, because it enabled the Brown robot to stay locked in on the human commander, which was essential to maintaining a set distance while following the person.
The result is a robot that doesn't require remote control or constant vigilance, Jenkins said, which is a key step to developing autonomous devices. The team hopes to add more nonverbal and verbal commands for the robot and to increase the three-foot working distance between the commander and the robot.
"What you really want is a robot that can act like a partner," Jenkins added. "You don't want to puppeteer the robot. You just want to supervise it, where you say, 'Here's your job. Now, go do it.'"
"Advances in enabling intuitive human-robot interaction, such as through speech or gestures, go a long way into making the robot more of a valuable sidekick and less of a machine you have to constantly command," added Chris Jones, research program manager at iRobot.
The research was funded by the U.S. Defense Advanced Research Projects Agency Information Processing Techniques Office (DARPA IPTO) and by the U.S. Office of Naval Research.
Adapted from materials provided by Brown University.