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Drastically Slowing Light
The team was co-led by Alan Willner, a professor in electrical engineering at the University of Southern California Viterbi School of Engineering who specializes in photonics, the study of using light to carry and process information. The results appear in the current issue of the Journal of Lightwave Technology. The key parameters are slowness of the light, maximum data modulation rate, and control of the delay. The new system, says Willner, "uses simple optical fiber and can potentially accommodate much higher data rates than the prior work using exotic atomic vapors. The slowing process in fiber can be readily controlled and can be compatible with ordinary transmission fiber." "Beyond these advantages," continued Willner, "the experiments led to deeper understanding of the tradeoffs involved in slowing light without simultaneously distorting the data bits themselves." The stakes are potentially huge. Laser light can carry an enormous volume of information optically via high-bandwidth optical fibers, but such signals invariably have to be converted back into electronic bits for most kinds of signal processing functions, such as data equalization, buffering, synchronization, and multiplexing......... Posted by: Kevin Permalink Source In Quest For Inexhaustible Energy SourceAs gas prices soar and greenhouse gases continue to blanket the atmosphere, the need for a clean, safe and cheap source of energy has never seemed more pressing.Researchers have long worked to meet that need, exploring alternative energy technologies such as wind and solar power. But, after decades of quiet progress, the spotlight is now on another potentially inexhaustible energy source. Seven countries signed an agreement in Brussels last week (May 24) to launch construction of the multibillion dollar International Thermonuclear Experimental Reactor (ITER) in southern France. The largest fusion-energy experiment ever conducted, ITER is the culmination of years of research by scores of scientists, and is poised to answer long-standing questions about the real-world viability of fusion energy. The United States, China, the European Union, India, Japan, the Republic of Korea and the Russian Federation are joint sponsors of the project, which will experimentally generate up to 500 million watts of energy. An international collective of physicists and engineers is working to both complement and lend expertise directly to the ITER initiative - and scientists at the University of Wisconsin-Madison are firmly placed among them. "[ITER] is a major threshold that we've been waiting to get to for 20 years," says Raymond Fonck, a UW-Madison professor of engineering physics and the chief scientist of ITER's U.S. project office. "The project is the No. 1 priority in fusion research in the country and the world, and essentially takes us to a regime we've never been to before"......... Posted by: Kevin Permalink Source Coordinating Fusion Science Effort
On May 24, the seven international ITER participants initialed an agreement to construct the experiment. The U.S. Department of Energy and its ITER Project Office - which stands for the International Thermonuclear Experimental Reactor - recently named engineering physics Professor Raymond Fonck chief scientist for the U.S. portion of the project. In his role as chief scientist, Fonck will help the project office answer scientific questions that arise as the project develops. For that, he will don his hat as director of the U.S. Burning Plasma Organization (USBPO) - a national organization of scientists in the fusion community that studies the properties of magnetically confined burning fusion plasmas, the ionized gasses that drive fusion-energy production. "So, if there are issues that arise, and they have to be resolved in the design of the device, you engage the science and engineering community here in this country to help answer those questions," Fonck says......... Posted by: Kevin Permalink Source Nanotechnology Explained
At the nanoscale, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter. Nanotechnology R&D is directed toward understanding and creating improved materials, devices, and systems that exploit these new properties. One area of nanotechnology R&D is medicine. Medical scientists work at the micro- and nano-scales to develop new drug delivery methods, therapeutics and pharmaceuticals. For a bit of perspective, the diameter of DNA, our genetic material, is in the 2.5 nanometer range, while red blood cells are approximately 2.5 micrometers. Additional information about nanoscale research in medicine is available from the National Institutes of Health. A nanometer is one-billionth of a meter; a sheet of paper is about 100,000 nanometers thick. See The Scale of Things for a comparative view of the sizes of usually known items and nanoscale particles......... Posted by: Kevin Permalink Source Pay-as-you-go Personal Computing Designed For Emerging Market
The pay-as-you-go business model makes PCs more accessible by dramatically reducing the entry cost and enabling customers to pay for their computer as they use it, through the purchase of prepaid cards. Market trials are starting first in emerging markets where inadequate access to consumer credit, unpredictable income and high entry costs prevent a number of consumers from purchasing a computer. The FlexGo technology supports Microsoft's global commitment to help people realize their potential through the benefits of personal computers. "Today there are already more than 1 billion prepaid mobile phones used around the world, so we know FlexGo enables a familiar and comfortable pay-as-you-go model that works for people with variable or unpredictable income," said Will Poole, senior vice president of the Market Expansion Group at Microsoft. "Offering unprecedented flexibility of PC ownership will bring high-quality personal computers within the reach of hundreds of millions of families and small businesses in emerging markets so they too can enjoy the a number of benefits PCs bring in education, entertainment, communication and productivity"......... Posted by: Kevin Permalink Source Detector Sees The Invisible
The detector, called a Quantum Well Infrared Photodetector (QWIP) array, was the world's largest (one million-pixel) infrared array when the project was announced in March 2003. It was a low-cost alternative to conventional infrared detector technology for a wide range of scientific and commercial applications. However, at the time it could only detect a narrow range of infrared colors, equivalent to making a conventional photograph in just black and white. The new QWIP array is the same size but can now sense infrared over a broad range. "The ability to see a range of infrared wavelengths is an important advance that will greatly increase the potential uses of the QWIP technology," said Dr. Murzy Jhabvala of NASA's Goddard Space Flight Center, Greenbelt, Md., Principal Investigator for the project. Infrared light is invisible to the human eye, but some types are generated by and perceived as heat. A conventional infrared detector has many cells (pixels) that interact with an incoming particle of infrared light (an infrared photon) and convert it to an electric current that can be measured and recorded. They are similar in principle to the detectors that convert visible light in a digital camera. The more pixels that can be placed on a detector of a given size, the greater the resolution, and NASA's QWIP arrays are a significant advance over earlier 300,000-pixel QWIP arrays, previously the largest available......... Posted by: Kevin Permalink Source Still More Accurate
NIST chemists Thomas Bruno and Beverly Smith analyze complex fuel mixtures with the new advanced distillation curve apparatus.
Credit: © Geoffrey Wheeler Petroleum-based fuels, with few exceptions, are highly complex mixtures of hundreds of distinct components from light butanes to increasingly heavy oils. For decades, distillation curves have been one of the most widely accepted ways of characterizing a fuel. The curve charts the percentage of the total mixture that has evaporated as the temperature of a sample is slowly heated. The curve holds a wealth of information--not just the basic makeup of the fuel, but also indicators as to how it will perform. Engine starting ability, fuel system icing, vapor lock, fuel injection scheduling, fuel auto-ignition, hot- and cold-weather performance, and exhaust emissions all have been correlated with features of the distillation curve. The data are important both for quality control at refineries and the design of specialty high-performance fuels......... Posted by: Sarah Permalink Source Glowing Nanowires
Growing, glowing nanowires
Lorelle Mansfield/NIST Scientists at the National Institute of Standards and Technology (NIST) are growing nanowires made of gallium nitride alloys and making prototype devices and nanometrology tools. The wires are grown under high vacuum by depositing atoms layer by layer on a silicon crystal. NIST is one of few laboratories capable of growing such semiconductor nanowires without using metal catalysts, an approach believed to enhance luminescence and flexibility in crystal design. The wires are generally between 30 and 500 nanometers (nm) in diameter and up to 12 micrometers long. When excited with a laser or electric current, the wires emit an intense glow in the ultraviolet or visible parts of the spectrum, depending on the alloy composition. A paper in the May 22 issue of Applied Physics Letters* reports that individual nanowires grown at NIST produce sufficiently intense light to enable reliable room-temperature measurements of their important characteristics. For example, the peak wavelength of light emitted with electric field parallel to the long axis of a nanowire is shifted with respect to the peak wavelength emitted with electric field perpendicular to the wire. Such differences in emission are used to characterize the nanowire materials and also may be exploited to make sensors and other devices......... Posted by: Kevin Permalink Source A Tiny, Self-powered Sensor
This is a close-up image of a tiny hydrogen sensor developed by University of Florida engineering researchers. The sensor uses extremely small zinc oxide nanorods, located within the black dots in the triangular base, to gauge the amount of hydrogen in the air. To power the sensor, the researchers designed a novel device that harvests energy from vibrations where the sensor is placed. A tiny wireless transmitter enables the sensor to transmit its results to a central base station.
(University of Florida)
Now, a team of more than a dozen University of Florida engineering faculty and graduate students has found a way to jump that hurdle: a tiny, inexpensive sensor device that can detect hydrogen leaks and sound the alarm by wireless communication. The cool part? The device, called a sensor node because it is designed to work in tandem with dozens or hundreds more like it, has the ability to draw its power from a tiny internal power source that harvests energy from small vibrations. That means future versions could one day operate continuously without batteries or maintenance when affixed to cars, refrigerators, pumps, motors or any other machine that gives off a slight vibration. "You need lots of hydrogen sensors to detect leaks, but you don't want to have to maintain them or change the battery every couple of months," said Jenshan Lin, an associate professor of electrical and computer engineering and the lead investigator on the NASA-funded sensor project. "Our sensor can operate completely independently". Lin and colleagues developed the sensor node over the past two years as a part of the NASA Hydrogen Research Program at UF. The program spans several research projects. NASA uses liquid hydrogen to fuel the space shuttle, and the goal of the $1 million-plus sensor project is to help the space agency improve the safety and reliability of all its hydrogen systems......... Posted by: Kevin Permalink Source Hope For The Blind
Recently the machine received positive feedback from 10 visually challenged people with a range of causes for their vision loss who tested it in a pilot clinical trial. The work was reported in Optometry, the Journal of the American Optometric Association, earlier this year. The work is led by Elizabeth Goldring, a senior fellow at MIT's Center for Advanced Visual Studies. She developed the machine over the last 10 years, in collaboration with more than 30 MIT students and some of her personal eye doctors. The new device costs about $4,000, low compared to the $100,000 price tag of its inspiration, a machine Goldring discovered through her eye doctor. Goldring's adventures at the intersection of art and high technology began with a visit to her doctor, Lloyd Aiello, head of the Beetham Eye Institute of the Joslin Diabetes Center. At the time, Goldring was blind. (Surgeries have since restored vision in one eye). To better examine her eyes, Aiello asked her to go to the Schepens Eye Research Institute at Harvard, where technicians peered into her eyes with a diagnostic device known as a scanning laser opthalmoscope, or SLO. With the machine they projected a simple image directly onto the retina of one eye, past the hemorrhages within the eye that contributed to her blindness. The idea was to determine whether she had any healthy retina left......... Posted by: Kevin Permalink Source |
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The ITER device
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