June 20, 2007, 9:55 AM CT

Giant magnetocaloric materials for the environment

Materials that change temperature in magnetic fields could lead to new refrigeration technologies that reduce the use of greenhouse gases, thanks to new research at the U.S. Department of Energy's Argonne National Laboratory and Ames National Laboratory.

Researchers carrying out X-ray experimentation at the Advanced Photon Source at Argonne - the nation's most powerful source of X-rays for research - are learning new information about magnetocaloric materials that have potential for environmentally friendly magnetic refrigeration systems.

Magnetic refrigeration is a clean technology that uses magnetic fields to manipulate the degree of ordering (or entropy) of electronic or nuclear magnetic dipoles in order to reduce a material's temperature and allow the material to serve as a refrigerant. New materials for refrigeration based on gadolinium-germanium-silicon alloys display a giant magnetocaloric effect due to unusual coupling between the material's magnetism and chemical structure.

Understanding this coupling is essential to moving this technology from the laboratory to the household. Magnetic refrigeration does not rely on hydrofluorocarbons (HFCs) used in conventional refrigeration systems. HFCs are greenhouse gases that contribute to global climate change when they escape into the atmosphere......... Posted by: Kevin      Read more         Source

June 10, 2007, 8:21 PM CT

High-Tech Help From Rescue Robot

National Institute of Standards and Technology (NIST) engineers are organizing the fourth in a series of Response Robot Evaluation Exercises for urban search and rescue (US&R) responders to be held on June 18-22, 2007, at Texas A&M's "Disaster City" training facility in College Station, Texas. These events, sponsored by the Department of Homeland Security's (DHS) Science and Technology Directorate, test robot performance on emerging standard test methods using actual training scenarios for emergency responders. The results will be used to refine the test methods, and in developing usage guides that match specific kinds of US&R robots to particular disaster scenarios.

This exercise will use two Disaster City training scenarios. A simulated structural collapse of a municipal building will allow responders to deploy robots to search for victims and assist in "rendering the structure safe" for responders to extricate those victims. This will require robots to face a variety of challenges as they traverse complex and confined spaces within the structure's semi-collapsed walls, sloping floors, rubble and voids while searching for victims. The robots will be deploying high-tech sensors such as laser scanners to capture the size and shape of interior voids to help structural engineers set up shoring supports......... Posted by: Kevin      Read more         Source

June 10, 2007, 8:18 PM CT

New Quantum Key System Combines Speed, Distance

Scientists at the National Institute of Standards and Technology (NIST) have built a prototype high-speed quantum key distribution (QKD) system, based on a new detector system that achieves dramatically lower noise levels than similar systems. The new system, they say, can perform a theoretically unbreakable "one-time pad" encryption, transmission and decryption of a video signal in real-time over a distance of at least 10 kilometers.

Key distribution-the problem of ensuring that both the sender and receiver of an encrypted message (and no one else) share the same long string of random digits (the so-called "key") used to encode and decode the message-has always been one of the most important challenges in cryptography. Since the 1980's it's been recognized that the unique properties of quantum mechanics-the fact that certain measurements cannot be made without altering the thing measured-offered the possibility of a system that could transmit as long a key as desired between two parties with no chance that it could be copied undetectably by a third party.

Since then the race has been on to build a fast, practical and reliable QKD system. One important requirement for any candidate system is that it be compatible with existing fiber-optic telecom networks that transmit at wavelengths of either 1550 or 1310 nanometers (nm) to reach the greatest distance. Another requirement is a highly efficient photon detector that can detect single photons reliably without introducing significant amounts of "noise." One of the best low-noise detectors, a silicon-based avalanche photo diode (Si-APD), does not function at the telecom wavelengths. Instead, it operates best at much shorter wavelengths around 700 nm. To take advantage of the Si-APD, the NIST group designed a sub-system to "up-convert" single photons from a transmission wavelength of 1310 nm to 710 nm for high-efficiency detection......... Posted by: Kevin      Read more         Source

June 6, 2007, 10:04 PM CT

Motion of a Single Electron on Video

To observe the motion of an electron - an elementary particle with a mass that is one billionth of a billionth of a billionth of a gram - has been considered to be impossible. So when two Brown University physicists showed movies of electrons moving through liquid helium at the 2006 International Symposium on Quantum Fluids and Solids in Kyoto, they raised some eyebrows.

The images, which were published online on April 28, 2007, in the Journal of Low Temperature Physics, show scattered points of light moving down the screen - some in straight lines, some following a snakelike path. The Matrix it's not. Still, the fact that they can be seen at all is astounding. "We were astonished when we first saw an electron moving across the screen," said Humphrey Maris, a professor of physics at Brown University. "Once we had the idea, setting it up was surprisingly easy".

Maris and Wei Guo, a doctoral student, took advantage of the bubbles that form around electrons in supercold liquid helium. Using sound waves to expand the bubbles and a coordinated strobe light to illuminate them, Guo was able to catch their movements on a home video camera.

A free electron repels the atoms that surround it, creating a small space, or bubble, around itself. In conventional liquids, the bubble shrinks to nothing because the surface tension of the liquid works against the repulsive force. Superfluid helium has very little surface tension, so the bubble can become much larger. The two opposing forces balance when the diameter of the bubble is about 40 angstroms - still far to tiny to see......... Posted by: Kevin      Read more         Source

June 1, 2007, 9:33 PM CT

Long-distance record -- 'Quantum keys' sent 200 kilometers

Palo Alto, Calif. -- Particles of light serving as quantum keysthe latest in encryption technologyhave been sent over a record-setting 200-kilometer fiber-optic link by scientists from the National Institute of Standards and Technology (NIST), NTT Corp. in Japan, and Stanford University. The experiment, using mostly standard components and transmitting at telecommunications frequencies, offers an approach for making practical inter-city terrestrial quantum communications networks as well as long-range wireless systems using communication satellites.

The demonstration, described in Nature Photonics,* was conducted in a Stanford lab with optical fiber wrapped around a spool. In addition to setting a distance record for quantum key distribution (QKD), it also is the first gigabit-rate experimenttransmitting at 10 billion light pulses per secondto produce secure keys. The rate of processed key productionthe keys corrected for errors and enhanced for privacywas much lower due to the long distance involved, and the key was not used to encrypt a digital message as it would be in a complete QKD system. QKD systems transmit a stream of single photons with their electric fields in different orientations to represent 1s and 0s, which are used to make quantum keys to encrypt and decrypt messages. Properly executed, quantum encryption is unbreakable because eavesdropping changes the state of the photons......... Posted by: Kevin      Read more         Source

May 25, 2007, 3:30 PM CT

Fiftieth Anniversary of First Digital Image

It was a grainy image of a baby-just 5 centimeters by 5 centimeters-but it turned out to be the well from which satellite imaging, Computerized axial tomography scans, bar codes on packaging, desktop publishing, digital photography and a host of other imaging technologies sprang.

It was 50 years ago this spring that National Bureau of Standards (NBS, now known as the National Institute of Standards and Technology, or NIST) computer pioneer Russell Kirsch asked "What would happen if computers could look at pictures?" and helped start a revolution in information technology. Kirsch and colleagues at NBS, who had developed the nation's first programmable computer, the Standards Eastern Automatic Computer (SEAC), created a rotating drum scanner and programming that allowed images to be fed into it. The first image scanned was a head-and-shoulders shot of Kirsch's three-month-old son Walden.

The ghostlike black-and-white photo only measured 176 pixels on a side-a far cry from today's megapixel digital snapshots-but it would become the Adam and Eve for all computer imaging to follow. In 2003, the editors of Life magazine honored Kirsch's image by naming it one of "the 100 photographs that changed the world".

Kirsch and his wife Joan, an art historian, now reside in Oregon. Together, they use computers to analyze paintings and define the artistic processes by which they were created. Son Walden-whose face helped launch the era of computerized photography-works in communications for Intel following a successful career as a television news reporter......... Posted by: Kevin      Read more         Source

May 25, 2007, 3:28 PM CT

New Fabrication Technique Yields Nanoscale UV LEDs

Scientists at the National Institute of Standards and Technology (NIST), in collaboration with researchers from the University of Maryland and Howard University, have developed a technique to create tiny, highly efficient light-emitting diodes (LEDs) from nanowires. As described in a recent paper,* the fabricated LEDs emit ultraviolet light-a key wavelength range mandatory for a number of light-based nanotechnologies, including data storage-and the assembly technique is well-suited for scaling to commercial production.

Light-based nanoscale devices, such as LEDs, could be important building blocks for a new generation of ultracompact, inexpensive technologies, including sensors and optical communications devices. Ultraviolet LEDs are especially important for data-storage and biological sensing devices, such as detectors for airborne pathogens. Nanowires made of a particular class of semiconductors that includes aluminum nitride, gallium nitride and indium nitride are the most promising candidates for nanoscale LEDs. But, says NIST researcher Abhishek Motayed, "The current nanowire LEDs are created using tedious nanowire manipulation methods and one-by-one fabrication techniques, which makes them unsuitable for commercial realization".

The NIST team used batch fabrication techniques, such as photolithography (printing a pattern into a material using light, similar to photography), wet etching and metal deposition. They aligned the nanowires using an electric field, eliminating the delicate and time-consuming task of placing each nanowire separately......... Posted by: Kevin      Read more         Source

Wed, 16 May 2007 03:55:27 GMT

Zero Emissions Skyscraper

With the great cities of the world already marked by their huge amount of greenhouse emissions, environmental scientists seem to start all over from the roots - the pollution free, pristine deserts.

The oil rich the Middle East are soon to get a 68-storied state-of-the-art tower. True, there is nothing new with building tall towers. What catapulted this tower to the headlines is its being a zero emission building.

Making to the number 22 on the list of the world’s tallest buildings, the giant building will rise to a lofty height of 322 meters (1,056 feet) and would supply 100% of its own energy to its offices.

So, what will make people look forward to the construction of the Burj al-Taqa meaning energy tower is not only its consuming very little energy, but its producing all its energy itself.

The $406 million project will have a giant solar shield that would cover nearly 2/3rds of the building surface. Its new generation of vacuum glazed windows would insulate against 50 degree Celsius heat of the desert.

The tower would also have a cooling system that would utilize renewable resources the seawater to be stored underground! A power generating giant solar panel island of 17,000 square meters will float on the ocean within the seaside towers view.

Seawater would be electrolyzed to produce hydrogen for powering fuel cell generators for use during the evening in the tower-offices.

Once built, the amazing zero emission, self-power producing tower would sure to project the world with an exemplary of how green world should beImage Posted by: Irani      Read more     Source

May 6, 2007, 5:26 PM CT

CT imaging and car crash testing

Crash test injuries analyzed with CT imaging provide valuable data that can help engineers develop safer cars and reduce the severity of injuries during car accidents, as per a new study by scientists from The Ohio State University in Columbus.

For the study, two human cadavers were hit with a device that simulates a blunt impact equivalent to car collisions. CT imaging of the rib cages of the cadavers waccording toformed to evaluate the damage caused by the impact. "We observed that injuries to the rib cage caused by the simulated car collision could be identified on the Computerized axial tomography scans and that the CT results correlated with the usual, more involved methods of body damage analysis, which makes use of high speed videos and data from sensors attached to more than 30 locations on the body during the impact," said Steffen Sammet, MD, PhD, lead author of the study.

"The study was initiated by a project from the Department of Transportation to enable objective, noninvasive measures of crash impacts. The knowledge gained from those tests goes directly into automotive engineering to prevent those disabling injuries or death," said Dr. Sammet.

In addition to saving lives through the design of safer cars, the scientists foresee other possible uses for the data gathered from CT imaging of crash tests. "A direct further outcome of this research is understanding how imaging findings correlate to the force of impact, which can further improve our ability to provide better diagnosis as well as help in the understanding of forensic aspects of car crashes," said Dr. Sammet......... Posted by: Sean      Read more         Source

May 6, 2007, 4:46 PM CT

Creating corn for cars

A new variety of corn developed and patented by Michigan State University researchers could turn corn leaves and stalks into products that are just as valuable as the golden kernels.

Right now, most U.S. ethanol is made from corn kernels. This is because breaking down the cellulose in corn leaves and stalks into sugars that can be fermented into ethanol is difficult and expensive.

"We've developed two generations of Spartan Corn," said Mariam Sticklen, MSU professor of crop and soil sciences. "Both corn varieties contain the enzymes necessary to break down cellulose and hemicellulose into simple sugars in their leaves. This will allow for more cost-effective, efficient production of ethanol".

Sticklen will co-chair a panel on energy crops for biofuels today at BIO2007, the annual international convention of the Biotechnology Industry Organization.

"In the future, corn growers will be able to sell their corn stalks and leaves as well as their corn grain for ethanol production," Sticklen said. "What is now a waste product will become an economically viable commodity"......... Posted by: Kevin      Read more         Source