Electronix Express Newsletter

September 2010 Issue

Welcome to the September 2010 Issue of the Electronix Express Newsletter

STORIES

Robotic Hummer Sets Speed and Distance Records

Air-Sniffing Cellphones Could Aid Chemical-Warfare Defense

Behind the Secrets of Silk Lie High-Tech Opportunities

Liquid Silk Lets Tiny Electrodes 'Melt' Onto Bumpy Brain Tissue

Radical New Computer Memory?

World's Tiniest Wires?

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1. Robotic Hummer Sets Speed and Distance Records

A robotic Hummer set records for speed, distance and duration in a recent test prior to a $2 million Defense Department competition later this year. Carnegie Mellon University's robotic Sandstorm vehicle, a Hummer converted to operate autonomously, covered 200 miles in seven hours without human help during a test run. Sandstorm will be one of 40 robots competing in the 2005 DARPA Grand Challenge, a 175-mile desert race with a $2 million winner-take-all prize. No vehicle managed to finish the challenging course last year.

The Sandstorm vehicle uses sensors to see and computers to drive. During the test, it covered 131 laps on a 1.5-mile racecourse at the BeaveRun MotorSports Complex 4 near Pittsburgh. It averaged 28 mph and hit a top speed of 36 mph. "That doesn't sound like a big deal for a human-driven car, but it is a very big deal for the pioneering of computer-driven vehicles," said robotics professor William L. "Red" Whittaker, leader of Red Team Racing. Wittaker said the terrain will be much tougher for the actual race Oct. 8 in the Mojave Desert. He remarks,"We are a desert racing team without a desert, so we test on local sites. Sandstorm ran a quick pace on this track, but the Mojave will not be so easy or forgiving. On July 4, we learned that our hardware and software are reliable, and that is important. To finish first, you must first finish."

Qualifying races will be held Sept. 26 to Oct. 6 at the California Speedway at Fontana, where 40 vehicles will be whittled to 20.

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2. Air-Sniffing Cellphones Could Aid Chemical-Warfare Defense

A sensor in your cellphone could alert you to a toxic leak in your immediate vicinity or it could alert government officials to a major terrorist attack with a chemical weapon. If the Department of Homeland Security has its way, cellphones will soon do more than transmit calls, GPS information and a host of data from the Web. They'll also monitor the air for toxic substances that could be part of a chemical warfare attack. Putting the crowdsourcing concept to work, it would be possible to assess the location, nature and the severity of such an attack in seconds.

Just as antivirus software springs to life when it spies suspicious activity, so Cell-All, from the DHS Science and Technology Directorate (S&T), regularly sniffs the surrounding air for certain volatile chemical compounds. When a threat is sensed, a warning is delivered in one of two ways. For personal safety issues such as a chlorine gas leak, a warning is sounded; users can choose a vibration, noise, text message or phone call for their alerts. For larger-scale catastrophes, such as a sarin gas attack, details including the time, location and compound are sent to an emergency operations center. Detection, identification and notification all take place in less than a minute, DHS says.

According to principal analyst Allen Nogee, "while the idea sounds like a good one, I think for it ever to fly, Homeland Security would need to convince citizens that this would be in their best interest." Toward that end, S&T is pursuing cooperative research and development agreements with Qualcomm , LG, Apple, and Samsung. "Our goal is to create a lightweight, cost-effective, power-efficient solution," said Stephen Dennis, Cell-All's program manager. The hope is to have 40 prototypes in about a year, focusing first on detecting carbon monoxide and fire. Cell-All will operate only on an opt-in basis and will transmit data anonymously, DHS stressed.

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3. Behind the Secrets of Silk Lie High-Tech Opportunities

Tougher than a bullet-proof vest yet synonymous with beauty and luxury, silk fibers are a masterpiece of nature whose remarkable properties have yet to be fully replicated in the laboratory. Thanks to their amazing mechanical properties as well as their looks, silk fibers have been important materials in textiles, medical sutures, and even armor for 5,000 years. But in recent years scientists have begun to unravel the secrets of silk. In the July 30, 2010, issue of the journal Science, Tufts biomedical engineering researchers Fiorenzo Omenetto, Ph.D., and David Kaplan, Ph.D., report that "Silk-based materials have been transformed in just the past decade from the commodity textile world to a growing web of applications in more high technology directions."

The Science paper notes that the development of silk hydrogels, films, fibers and sponges is making possible advances in photonics and optics, nanotechnology, electronics, adhesives and microfluidics, as well as engineering of bone and ligaments. Because silk fiber formation does not rely on complex or toxic chemistries, such materials are biologically and environmentally friendly, even able to integrate with living systems. Silk spun by spiders and silk worms combines high strength and extensibility. This one-two punch is unmatched by synthetics, even though silk is made from a relatively simple protein processed from water. Techniques for reprocessing natural silk protein in the lab continue to advance. Silks are also being cloned and expressed in a variety of hosts, including E. coli bacteria, fungi, plants and mammals, and through transgenic silkworms.

Down the silk road of the future, Kaplan and Omenetto believe applications could include degradable and flexible electronic displays for sensors that are biologically and environmentally compatible and implantable optical systems for diagnosis and treatment. Support for this research on silk comes from the National Institutes of Health, National Science Foundation, Air Force Office of Science Research and the Defense Advanced Research Projects Agency. Fundamental discoveries into how silk fibers are made have shown that chemistry, molecular biology and biophysics all play a role in the process. These discoveries have provided the basis for a new generation of applications for silk materials, from medical devices and drug delivery to electronics.

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4. Liquid Silk Lets Tiny Electrodes 'Melt' Onto Bumpy Brain Tissue

People suffering from epileptic seizures or spinal cord injuries may have a highly effective new form of treatment available in a few years. Scientists have found a way to print tiny electrodes onto liquid silk, allowing them to melt to conform with the brain's bumpy shape. Up to now, devices designed to measure and enhance signals routed through brain circuitry have been hampered by the complexities of the folded surface of brain tissue. However, the development of a brain implant that conforms so closely to the brain's surface could change all of that according to a study published in Nature Materials.

The implant has ultra-thin electrode arrays affixed to film made from highly refined liquid silk. The material is thin enough to follow the folds and curves of a human's bumpy brain but strong enough to allow complex electronic circuitry to be printed on it. The implants have possibilities for treating epilepsy, spinal cord injuries and other neurological disorders, said Walter Koroshetz, M.D., deputy director of the National Institute of Neurological Disorders and Stroke (NINDS), which funded the research. The super-thin devices can record brain activity more accurately than currently used thicker implants.

The first human applications of the new technology likely will be in the diagnostic arena. Thus, the implants could be used to first detect and then interrupt seizures by delivering electronic pulses that would stop the abnormal brain activity. In the case of people with spinal cord injuries, the technology has promise for reading complex signals in the brain that direct movement and then routing those signals to healthy muscles or prosthetic devices, according to the researchers. The electrodes printed on the surface of the silk material are only about 500 microns thick, or about five times the thickness of a human hair. The flexibility of the material also reduces the sharpness of the edges of the implants and should cause less damage to brain tissue.

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5. Radical New Computer Memory?

Research by scientists at Stanford University and RIKEN has revealed new clues on the microscopic processes by which resistance in certain materials is dramatically altered by the presence of magnetic fields. The discovery provides fundamental insights toward the development of radically new memory and switching devices as reported in Science.

Colossal magnetoresistance (CMR), a phenomenon in which enormous variations in resistance are produced by small magnetic field changes, has attracted attention as a means to develop low-power, more compact alternatives to conventional circuits. Held in place by a lattice that constrains their movement, electrons in the manganites and other transition metal oxides in which CMR occurs interact strongly with each other, unlike semiconductors such as silicon. Further, CMR is triggered when a strong magnetic field induces such materials to tip from a charge-ordered insulating phase into a ferromagnetic metallic phase. The entire process drastically alters the material's properties. An earlier technique developed by the team was successful in producing manganite films only a few dozen nanometers thick capable of undergoing this transition from insulating to metallic phase.

To explore the mechanisms underlying this transition, the researchers adapted a microwave impedance microscope to withstand cryogenic temperatures and extreme magnetic fields. Using this microscope, they discovered that under a powerful 9 tesla magnetic field, filamentary metallic domains emerge in the manganite films, forming an interconnected network aligned along the axes of the film substrate. The discovery of this network, the first ever evidence of a microscopic mechanism for CMR, greatly enhances our understanding of microscopic phase transitions in thin film manganites. It also marks a major advance in the race toward new memory and switching devices, whose impact promises to revolutionize computing technology.

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6. World's Tiniest Wires?

Nanowires are so tiny that a human hair would dwarf them -- some have diameters 150 billionths of a meter. Because of their small size, surface tension that occurs during the manufacturing process pulls them together, limiting their usefulness. This is a problem because the wires are seen as a potential core element of new and more powerful microelectronics, solar cells, batteries and medical tools. Kirk Ziegler, an assistant professor of chemical engineering at the University of Florida, said nanowires are most often made today with a process that involves the immersion of the wires. But in a paper in the journal ACS Applied Materials and Interfaces now online, he says he has found an inexpensive solution.

When complete, each wire is supposed to poke up right next to the other from a flat surface, like bristles on a Lilliputian toothbrush. But Ziegler said the wires are so tiny and so flexible that surface tension clumps them up when dried. Ziegler and Justin Hill, who will graduate from UF with a doctorate in chemical engineering this summer, realized that they needed to introduce a force that counteracted that of the surface tension. They came up with a process simple enough to be achievable with a nine-volt battery. The researchers apply an electrical charge to the nanostructures during the manufacturing process, charging each tiny wire and making it repel its neighbor. According to Ziegler, "As the two nanowires pull toward each other because of the surface tension, the like charges at the tips act to push them apart. The aim is to get a net zero force on the structure, so the nanowires stand straight." Tests of microscope-slide-sized surfaces, each containing trillions of nanowires, showed that the procedure effectively prevents clumping.

Nanowires have not found wide commercial applications to date, but Ziegler said that as engineers learn how to make and manipulate them, they could underpin far more efficient solar cells and batteries because they provide more surface area and better electrical properties. "Being able to pack in a higher density of nanowires gives you a much higher surface area, so you start to generate higher energy density," he said. Ziegler said that biomedical engineers are also interested in using the wires to help deliver drugs to individual cells, or to hinder or encourage individual cell growth. The University of Florida has applied for a patent on the process, he added.

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