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July 19, 2006, 11:24 PM CT

Cluster Hits The Magnetic Bull's-eye

Cluster Hits The Magnetic Bull's-eye Credits: Dr. Xiao/Chinese Academy of Sciences (Beijing)
ESA's spacecraft constellation Cluster has hit the magnetic bull's-eye. The four spacecraft surrounded a region within which the Earth's magnetic field was spontaneously reconfiguring itself.

This is the first time such an observation has been made and gives astronomers a unique insight into the physical process responsible for the most powerful explosions that can occur in the Solar System: the magnetic reconnection.

When looking at the static pattern of iron filings around a bar magnet, it is difficult to imagine how changeable and violent magnetic fields can be in other situations.

In space, different regions of magnetism behave somewhat like large magnetic bubbles, each containing electrified gas known as plasma. When the bubbles meet and are pushed together, their magnetic fields can break and reconnect, forming a more stable magnetic configuration. This reconnection of magnetic fields generates jets of particles and heats the plasma.

At the very heart of a reconnection event, there must be a three dimensional zone where the magnetic fields break and reconnect. Scientists call this region the null point but, until now, have never been able to positively identify one, as it requires at least four simultaneous points of measurements.........

Posted by: Edwin      Permalink         Source

July 19, 2006, 10:22 PM CT

Corn Waste To Create Electricity

Corn Waste To Create Electricity
After the corn harvest, whether for cattle feed or corn on the cob, farmers commonly leave the stalks and stems in the field, but now, a team of Penn State scientists thinks corn stover can be used not only to manufacture ethanol, but to generate electricity directly.

"People are looking at using cellulose to make ethanol," said Bruce E. Logan, the Kappe professor of environmental engineering. "You can make ethanol from exploded corn stover, but once you have the sugars, you can make electricity directly".

Logan's process uses a microbial fuel cell to convert organic material into electricity. Prior work has shown that these fuel cells can generate electricity from glucose and from municipal wastewater and that these cells also can directly generate hydrogen gas.

Corn stalks and leaves, amassing 250 million tons a year, make up a third of the total solid waste produced in the United States. Currently, 90 percent of corn stover is left unused in the field. Corn stover is about 70 percent cellulose or hemicellulose, complex carbohydrates that are locked in chains. A steam explosion process releases the organic sugars and other compounds in the corn waste and these compounds can be fed to microbial fuel cells.

The microbial fuel cells contain two electrodes and anaerobic bacteria -- bacteria that do not need oxygen -- that consume the sugars and other organic material and release electrons. These electrons travel to the anode and flow in a wire to the cathode, producing electrical current. The water in the fuel cell donates positive hydrogen atoms that combine with the electrons and oxygen to form water.........

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July 19, 2006, 9:10 PM CT

Predicting Crystal Structures

Predicting Crystal Structures Professor Gerbrand Ceder holds up a model of a perovskite crystal
Photo / Donna Coveney
The same computer methods used by online sales sites to suggest books to customers can help predict the crystal structures of materials, MIT researchers have found.

These structures are key to designing new materials and improving existing ones, which means that everything from batteries to airplane wings could be influenced by the new method.

The scientists report their findings in the July 9 online edition of Nature Materials.

Using a technique called data mining, the MIT team preloaded the entire body of historical knowledge of crystal structures into a computer algorithm, or program, which they had designed to make correlations among the data based on the underlying rules of physics.

Harnessing this knowledge, the program then delivers a list of possible crystal structures for any mixture of elements whose structure is unknown. The team can then run that list of possibilities through a second algorithm that uses quantum mechanics to calculate precisely which structure is the most stable energetically -- a standard technique in the computer modeling of materials.

"We had at our disposal all of what is known about nature," said Professor Gerbrand Ceder of the Department of Materials Science and Engineering, leader of the research team. Ceder compared the database of crystal structures to the user database of an online bookseller, which can make correlations among millions of customers with similar interests. "If you tell me you've read these 10 books in the last year and you rate them, can I make some prediction about the next book you're going to like?".........

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July 18, 2006, 10:34 PM CT

Xploring Mars With Mini Probes

Xploring Mars With Mini Probes An artist's rendering shows the baseball-sized probes
Illustration / Gus Frederick
MIT engineers and scientist colleagues have a new vision for the future of Mars exploration: a swarm of probes, each the size of a baseball, spreading out across the planet in every direction.

Thousands of probes, powered by fuel cells, could cover a vast area now beyond the reach of today's rovers, including exploring remote and rocky terrain that large rovers cannot navigate.

"They would start to hop, bounce and roll and distribute themselves across the surface of the planet, exploring as they go, taking scientific data samples," said Steven Dubowsky, the MIT professor of mechanical engineering who is leading the research team.

Dubowsky's team plans to test prototypes on Earth this fall and estimates that a trip to Mars is about 10 years away. He is now working with Penelope Boston, director of the cave research program at the New Mexico Institute of Mining and Technology, to create probes that can handle the rough terrain of Mars.

Researchers think that lava tubes usually seen on Mars are a promising location to search for signs of water. Lava tubes are tunnels left behind by underground lava flows. Signs of these tubes, which are also present in a number of locations on Earth, can be seen above ground.

The tubes could be entered through holes that formed on the Mars surface where sections of the tubes have collapsed, but these formations are too treacherous for today's rovers to explore. However, tiny bouncing probes could make their way inside the caves.........

Posted by: Edwin      Permalink         Source

July 17, 2006, 9:06 PM CT

Test Combustion For NASA

Test Combustion For NASA Hua Xu, left, an Iowa State graduate student in mechanical engineering, and Jerry Colver, an Iowa State emeritus professor of mechanical engineering, load part of their combustion test
Jerry Colver had visitors to his Iowa State University laboratory cover their ears. Then he powered up his test rig and -- SNAP! -- what looked like a bolt of blue lightning popped through five test chambers.

Colver, an Iowa State emeritus professor of mechanical engineering, will use that spark to ignite and burn combustible powders uniformly suspended inside narrow test chambers as part of a test for the National Aeronautics and Space Administration.

But it's not just a matter of exploding powders in a lab. He'll ignite powders as they drop eight stories at NASA's Glenn Research Center in Cleveland. During the drops, the test rig will accelerate to a speed of about 50 miles per hour and approach zero-gravity conditions before landing in an air bag. The test drops are scheduled to begin in early August.

NASA is supporting the research with a $395,000 grant. NASA researchers want to learn how much of a gap there needs to be in a test chamber before powders will ignite. Colver said the research is important to NASA for improving fire safety and developing a new safety standard. He also said the research will advance scientists' basic understanding of flame theory.

"We want to know under what conditions powders will burn, their flammability and the ignition power required," Colver said.........

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July 17, 2006, 8:20 PM CT

Next-generation High-altitude Airships

Next-generation High-altitude Airships
"Paint-on" antennas, designed to establish new high-altitude communications and surveillance platforms, successfully transmitted voice and data links as well as teleconferencing capabilities during test flights in the Nevada desert June 21 on board an SA-60 spherical airship.

RTI International and its research partners at Unitech, Applied EM, the International Communications Group, and TechSphere Systems International, a wholly owned subsidiary of Cyber Defense Systems, successfully tested the antennas from several positions on the airship. The experiment provided the first opportunity to test and evaluate the electrical, electromagnetic and mechanical properties of the "paint-on" antenna technology during an actual flight.

"The successful airship test flights demonstrate exciting possibilities for 'paint-on' antenna technologies," said David Myers, vice president of RTI's Engineering and Technology Unit. "This new technology can be used to assist with hurricane disaster relief, provide enhanced security of ports and borders, perform science observation missions and improve military communications".

High-altitude airships can be used for both defense and homeland security purposes including surveillance of battlefields and domestic borders and ports. The airships are intended to serve as economical station-keeping communications and/or ground-sensing platforms that will augment both ground-based and more expensive satellite systems. The airships will operate well above commercial air traffic and the jet stream and beyond the range of most ground-to-air missiles.........

Posted by: Edwin      Permalink         Source

July 17, 2006, 8:16 PM CT

Sub-millimetre Astronomy In Full Swing

Sub-millimetre Astronomy In Full Swing The APEX-Telescope
The Atacama Pathfinder Experiment (APEX) 12-m sub-millimetre telescope lives up to its ambitions of providing access to the "Cold Universe" with unprecedented sensitivity and image quality. As a demonstration, no less than 26 articles based on early science with APEX are published this week in the research journal Astronomy & Astrophysics. Among the a number of new findings, most in the field of star formation and astrochemistry, are the discovery of a new interstellar ion and the detection of CO radiation at 0.2 mm and of H2D+ radiation.

Using both APEX and the IRAM 30-metre telescope the first astronomical detection of a charged molecule composed of carbon and fluorine - the 'CF+ ion' - was made. Previous to this discovery, only one fluorine-containing molecular species had been found in space so far, the HF molecule ('hydrogen fluoride'), consisting of one atom of hydrogen and one of fluorine. The newly discovered molecule, produced through a reaction between carbon and the HF molecule, was found in a region adjoining the Orion Nebula, one of the nearest and most active stellar nurseries in the Milky Way. This detection provides support to the astronomers' understanding of interstellar fluorine chemistry, suggesting that hydrogen fluoride is ubiquitous in interstellar gas clouds.........

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July 17, 2006, 8:11 PM CT

Perception Into Robots

Perception Into Robots
The Max Planck Institute for Biological Cybernetics is a partner in the Integrated Research Project BACS (Bayesian Approach to Cognitive Systems), which is being sponsored by the EU and will run until 2010. In this project, researchers are investigating the extent to which Bayes' theorem can be used in artificial systems capable of managing complex tasks in a real world environment. The Bayesian theorem is a model for rational judgment when only uncertain and incomplete information is available.

We are sitting in a soccer stadium and discover our neighbor sitting in the 10th row. We recognize him with no difficulty at all, even though he is wearing sunglasses and a cap in his club colors. Complex recognition processes like this work because the brain, sensory organs and nerve pathways are able to pick up stimuli and process them. The ability to classify things (categorization) appears to be a fundamental characteristic of human intelligence, and one that gives robots a real "headache". In situations in which a robot has no access to knowledge of a pre-defined environment, and pre-programmed control is therefore not possible, the robot will tend to fail miserably in its task. But it is precisely autonomous robots capable of acting in response to a given situation that could be of great use to humans.........

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July 17, 2006, 6:27 PM CT

Fiber Webs That See

Fiber Webs That See A sphere-shaped web of photo-detecting fibers developed by MIT scientists can sense the optical properties of the entire volume of space around it, as well as detect the source of incoming light. Image courtesy / Greg Hren
In a radical departure from conventional lens-based optics, MIT scientists have developed a sophisticated optical system made of mesh-like webs of light-detecting fibers. The fiber constructs, which have a number of advantages over their lens-based predecessors, are currently capable of measuring the direction, intensity and phase of light (a property used to describe a light wave) without the lenses, filters or detector arrays that are the classic elements of optical systems such as eyes or cameras.

Ultimately the researchers expect the new system will be capable of much more, with potential applications ranging from improved space telescopes to clothing that provides situational awareness to soldiers or even the visually impaired.

The transparent fiber-webs could even enable huge computer screens to be activated with beams of light instead of the touch of a finger. "We could use light to enhance interaction with computers and even gaming systems," said Professor Yoel Fink of the Department of Materials Science and Engineering and the Research Lab of Electronics, leader of the team. "It's intriguing--the idea of touching with light".

The scientists report the work in the June 25 online edition of Nature Materials, and it is featured on the cover of the July print issue of the magazine.........

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July 17, 2006, 5:09 AM CT

Mercury atomic clock

Mercury atomic clock
An experimental atomic clock based on a single mercury atom is now at least five times more precise than the national standard clock based on a "fountain" of cesium atoms, as per a paper by physicists at the Commerce Department's National Institute of Standards and Technology (NIST) in the July 14 issue of Physical Review Letters.

The experimental clock, which measures the oscillations of a mercury ion (an electrically charged atom) held in an ultra-cold electromagnetic trap, produces "ticks" at optical frequencies. Optical frequencies are much higher than the microwave frequencies measured in cesium atoms in NIST-F1, the national standard and one of the world's most accurate clocks. Higher frequencies allow time to be divided into smaller units, which increases precision.

A prototype mercury optical clock was originally demonstrated at NIST in 2000. Over the last five years its absolute frequency has been measured repeatedly with respect to NIST-F1. The improved version of the mercury clock is the most accurate to date of any atomic clock, including a variety of experimental optical clocks using different atoms and designs.

The current version of NIST-F1--if it were operated continuously--would neither gain nor lose a second in about 70 million years. The latest version of the mercury clock would neither gain nor lose a second in about 400 million years.........

Posted by: John      Permalink         Source

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