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Welcome to the May 2010 Issue of the Electronix Express Newsletter
STORIES |
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The new system offers a better way to control LEDs, which are relatively efficient and long-lasting compared to conventional lights, by taking advantage of the fact that they run on low-voltage direct current power. Current LED-based systems require transformers at each light to convert the higher-voltage alternating current in conventional wiring into lower-voltage direct current. The new system converts alternating current to low-voltage direct current at a central location, rather than at each light. This more efficient method cuts energy consumption by 10 to 20 percent, according to Jeremy Stieglitz, vice president of marketing for Redwood Systems, which will start selling its systems this summer.
The remaining energy savings come from using sensors and a central controller to reduce light use. The company has also developed a method for using those same power cables to carry data. Each LED can be fitted with inexpensive sensors that can be used to optimize light levels and ensure the lights are operating efficiently. Such sensors can also provide detailed information about temperature and where people are in the building--information that can be used to control heating and cooling systems. The sensing and controls, says Steiglitz, add very little cost to the new system because the network connections and power supply for the sensors are already in place.
"It is a very impressive advance for electrical mapping of the heart. This jump in mapping capability could markedly reduce and simplify these procedures and many other interventions," says Eric Topol, a cardiologist and director of the Scripps Translational Science Institution, in La Jolla, CA. Today the average ablation procedure for arterial fibrillation takes about three hours at best. The flexible device could be used in other kinds of biological sensors, including devices for monitoring neurological conditions such a Parkinson's and epilepsy. The work, which also involved researchers from Northwestern University, is published in the journal Science Translational Medicine. So far the device has been tested successfully in pigs.
Subhasish Mitra, professor of electrical engineering and computer science at Stanford and colleagues have developed a method that uses a small number (about 1 percent) of the transistors on a chip to record a log of chip activity--the instructions that pass through the chip's circuits. This log can be extracted from the chip, dumped into a computer, and analyzed to find out where the bugs are. The Stanford researchers' approach, called instruction footprint recording and analysis (IFRA), was designed to collect just the right amount of information about the chip's activity at just the right time. As trillions of instructions stream through a chip, information describing those instructions pass through so-called circular buffers, containers that hold information for a short time before being refreshed. When a failure or hint of an impending failure is detected, the system stops recording in the circular buffers and saves the buggy instructions.
When a chip fails, data that represents the chip's activity has been transferred to a computer. Software developed by the researchers decodes the labels, laying out the instructions--and the corresponding location on the chip--that led to the failure. Engineers, once they know the location of the bug, can make small changes, such as changing the timing of instructions, to keep the error from recurring. This is in contrast with the current method used. Engineers pulse electrical signals through the chip, mimicking the electrical activity seen during normal operation. If a chip fails during these tests, engineers try to re-create the electrical signals that caused the problem. These electrical simulations are arduous and time consuming. However Mitra's method can catch evidence of the bugs while they happen, eliminating much of the time spent doing electrical simulations.
The researchers hypothesize that the radiation prevented the buildup of amyloid plaques, the sticky protein aggregates that are found in Alzheimer's brains. They suggest that their work may eventually lead to a treatment that can halt the disease process. Studies in mice are preliminary. Of course many avenues of treatment that seem promising in rodents fail to pan out in humans. But the new paper raises questions about the cell phone industry's claim that its products' emissions are too weak to have any biological effects. Although the link to brain tumors remains inconclusive, the new work suggests cell phones may indeed be messing with our minds.
The secret, according to Menlo Park, Calif.-based InVisage Technologies, Inc., is a new material called QuantumFilm. QuantumFilm is an extremely light absorbent coating, according to InVisage, that will enable pixel sensors to capture about 95 percent of an image, nearly a fourfold increase over current image sensors. A typical camera phone pixel sensor consists of several layers, including a base layer of silicon used by the sensor's electronic transistors and photodetectors. The top layer, typically made of colored plastic or glass, acts as an array of color filters. Sandwiched in between are many layers of metal needed to connect the silicon electronic transistors together. However, because the light coming into the sensor has to pass through several layers of metal before reaching the silicon, which is a weak light absorber, the sensor detects only about 25 percent of the light that makes up the image.
QuantumFilm's dots are only a few nanometers in diameter, about the thickness of a biological cell membrane. Whereas there are a number of different ways to make quantum dots, one of the most common is colloidal synthesis, where they are grown using a combination of chemicals and heat. The dots-whose composition depends on the chemicals used to fabricate them-form in different shapes and sizes, and both of these factors determine their conducting properties. Smaller dots emit colors closer to the blue end of the spectrum. The larger they get, the redder they get. QuantumFilm exists today as a working prototype, with InVisage planning to have production-quality samples ready by year's end.
The researchers have integrated flexible, transparent electrodes with an energy-scavenging material to make a film that could provide supplementary power for portable electronics. The screens take advantage of the piezoelectric effect--the tendency of some materials to generate an electrical potential when they're mechanically stressed. Samsung's experimental device sandwiches piezoelectric nanorods between highly conductive graphene electrodes on top of flexible plastic sheets. The group's aim is to replace the rigid and power-consuming electrodes and sensors used on the front of today's touch-screen displays with a flexible touch-sensor system that powers itself. Ultimately, this setup might generate enough power to help run the display and other parts of the device functions. Rolling up such a screen, for instance, could help recharge its batteries.
"The flexibility and rollability of the nano-generators gives us unique application areas such as wireless power sources for future foldable, stretchable, and wearable electronics systems," says Sang-Woo Kim, professor of materials science and engineering at Sungkyunkwan University. Kim led the research with Jae-Young Choi, a researcher at Samsung Advanced Institute of Technology.
The bigger question is whether or not Apple can keep the momentum of iPad sales going. Now that there are effectively six models to choose from (Wi-Fi 16GB, 32GB, and 64GB; and Wi-Fi+3G 16GB, 32GB, and 64GB), users have plenty of choice. Prices range from $499 to $829 depending on storage size and whether or not users go with 3G. Apple's next quarterly report will shed some light on the demand for iPads, as will the 2010 holiday season.
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