November 7, 2007, 4:49 AM CT

Enhancing Mother Nature's carbon handling mechanism

Taking a page from Nature herself, a team of scientists developed a method to enhance removal of carbon dioxide from the atmosphere and place it in the Earth's oceans for storage.

Unlike other proposed ocean sequestration processes, the new technology does not make the oceans more acid and may be beneficial to coral reefs. The process is a manipulation of the natural weathering of volcanic silicate rocks.

Reporting in today's (Nov. 7) issue of Environmental Science and Technology, the Harvard and Penn State team explained their method.

"The technology involves selectively removing acid from the ocean in a way that might enable us to turn back the clock on global warming," says Kurt Zenz House, graduate student in Earth and planetary sciences, Harvard University. "Essentially, our technology dramatically accelerates a cleaning process that Nature herself uses for greenhouse gas accumulation".

In natural silicate weathering, carbon dioxide from the atmosphere dissolves in fresh water and forms weak carbonic acid. As the water percolates through the soil and rocks, the carbonic acid converts to a solution of alkaline carbonate salts. This water eventually flows into the ocean and increases its alkalinity. An alkaline ocean can hold dissolved carbon, while an acidic one will release the carbon back into the atmosphere. The more weathering, the more carbon is transferred to the ocean where some of it eventually becomes part of the sea bottom sediments......... Posted by: Kevin      Read more         Source

November 6, 2007, 10:34 PM CT

Stream of sand grains, exotic plasma at birth of universe

Streams of granular particles bouncing off a target in a simple tabletop experiment produce liquid-like behavior also witnessed in a massive research apparatus that simulates the birth of the universe. A team led by the University of Chicago's Sidney Nagel and Heinrich Jaeger report this surprising finding in the Oct. 27-Nov. 2 issue of Physical Review Letters.

"Nature plays the tricks that it knows how to play over and over again," said Nagel, the Stein Freiler Distinguished Service Professor in Physics at Chicago. Nagel and Jaeger co-authored the paper, along with Xiang Cheng, a graduate student in physics at Chicago; German Varas, a graduate student in physics at the University of Chile; and Daniel Citron, a Chicago undergraduate in physics.

Researchers have attained a good understanding of equilibrium phenomena, which are governed primarily by temperature or pressure. But what about phenomena that have been pushed far beyond their equilibrium states, like a jet of sand" What about quark-gluon plasma, the mixture of subatomic particles that existed for perhaps a few millionths of a second after the big bang".

"We really don't know what the right concepts are to describe this," Nagel said. "We love the physics of granular material because it allows us entre into this question in relatively simple experiments"......... Posted by: Kevin      Read more         Source

November 4, 2007, 8:07 PM CT

Heavier hydrogen on the atomic scale

Researchers may be one step closer to understanding the atomic forces that cause friction, thanks to a recently published study by scientists from the University of Pennsylvania, the University of Houston and the U.S. Department of Energy's Argonne National Laboratory.

The research, led by Robert Carpick of the University of Pennsylvania, found a significant difference in friction exhibited by diamond surfaces that had been coated with different isotopes of hydrogen and then rubbed against a small carbon-coated tip.

Researchers lack a comprehensive model of friction on the nanoscale and only generally grasp its atomic-level causes, which range from local chemical reactions to electronic interactions to phononic, or vibrational, resonances.

To investigate the latter, Argonne scientist Anirudha Sumant and colleagues used single-crystal diamond surfaces coated with layers of either atomic hydrogen or deuterium, a hydrogen atom with an extra neutron. The deuterium-terminated diamonds had lower friction forces because of their lower vibrational frequencies, an observation that Sumant attributed to that isotope's larger mass. They have also observed same trend on a silicon substrate, which is structurally similar to that of diamond.

Prior attempts to make hydrogen-terminated diamond surfaces relied on the use of plasmas, which tended to etch the material......... Posted by: Kevin      Read more         Source

November 1, 2007, 8:26 PM CT

Phoenix:Tasks En Route to Mars Include Course Tweak, Gear Checks

NASA's Phoenix Mars Lander, launched on Aug. 4 and headed to Mars, fired its four trajectory correction thrusters Wednesday for only the second time. The 45.9-second burn nudged the spacecraft just the right amount to put it on a course to arrive at the red planet seven months from today.

At Mars, Phoenix will face a challenging 7-minute descent through the atmosphere to land in the far north on May 25, 2008. After landing, it will use a robotic digging arm and other instruments during a three-month period to investigate whether icy soil of the Martian arctic could have ever been a favorable environment for microbial life. The solar-powered lander will also look for clues about the history of the water in the ice and will monitor weather as northern Mars' summer progresses toward fall.

The second course adjustment had been postponed a week to allow time for carefully returning the spacecraft to full operations after a cosmic-ray strike disrupted a computer memory chip Oct. 6. Experiences with prior spacecraft have shown hits by cosmic rays are a known hazard in deep space. The Phoenix spacecraft properly followed its onboard safety programming by putting itself into a precautionary standby state when the event occurred. Mission controllers then followed step-by-step procedures to understand the cause and resume regular operations......... Posted by: Brooke      Read more         Source

November 1, 2007, 8:04 PM CT

Light-powered micro-machines

A new theory developed at MIT could lead to "smart" optical microchips that adapt to different wavelengths of light, potentially advancing telecommunications, spectroscopy and remote sensing.

Drawn by the promise of superior system performance, scientists have been exploring the concept of microchips that manipulate light instead of electricity. In their new theory, the MIT team has shown how such chips could feature tiny machines with moving parts powered and controlled by the very light they manipulate, giving rise to fundamentally new functionality.

"There are thousands of complex functions we could make happen by tinkering with this idea," said Peter Rakich, an MIT postdoctoral associate who invented the theoretical concept along with postdoc Milos Popovic. The work was described in the cover story of the recent issue of Nature Photonics.

For example, such chips could one day be used to remotely adjust the amount of bandwidth available in an optical network, or to automatically process signals flowing through fiber-optic networks, without using any electrical power, Rakich said.

Coauthors on the paper were Marin Soljacic, assistant professor of physics; and Erich Ippen, the Elihu Thomson Professor of Electrical Engineering and professor of physics......... Posted by: Kevin      Read more         Source

October 31, 2007, 8:07 PM CT

Scientists discover new way to make water

In a familiar high-school chemistry demonstration, an instructor first uses electricity to split liquid water into its constituent gases, hydrogen and oxygen. Then, by combining the two gases and igniting them with a spark, the instructor changes the gases back into water with a loud pop.

Researchers at the University of Illinois have discovered a new way to make water, and without the pop. Not only can they make water from unlikely starting materials, such as alcohols, their work could also lead to better catalysts and less expensive fuel cells.

We observed that unconventional metal hydrides can be used for a chemical process called oxygen reduction, which is an essential part of the process of making water, said Zachariah Heiden, a doctoral student and lead author of a paper accepted for publication in the Journal of the American Chemical Society, and posted on its Web site.

A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you cant simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.

In English, the equation says: To produce two molecules of water (H2O), two molecules of diatomic hydrogen (H2) must be combined with one molecule of diatomic oxygen (O2). Energy will be released in the process......... Posted by: Sarah      Read more         Source

October 31, 2007, 7:30 PM CT

First Fully Functional Nanotube Radio

Make way for the real nanopod and make room in the Guinness World Records. A team of scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley have created the first fully functional radio from a single carbon nanotube, which makes it by several orders of magnitude the smallest radio ever made.

"A single carbon nanotube molecule serves simultaneously as all essential components of a radio - antenna, tunable band-pass filter, amplifier, and demodulator," said physicist Alex Zettl, who led the invention of the nanotube radio. "Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation (FM and AM), we were able to demonstrate successful music and voice reception."

Given that the nanotube radio essentially assembles itself and can be easily tuned to a desired frequency band after fabrication, Zettl believes that nanoradios will be relatively easy to mass-produce. Potential applications, in addition to incredibly tiny radio receivers, include a new generation of wireless communication devices and monitors. Nanotube radio technology could prove particularly valuable for biological and medical applications.

"The entire radio would easily fit inside a living cell, and this small size allows it to safely interact with biological systems," Zettl said. "One can envision interfaces with brain or muscle functions, or radio-controlled devices moving through the bloodstream"......... Posted by: Kevin      Read more         Source

October 31, 2007, 7:21 PM CT

Let there be light

Engineers at Florida State Universitys National High Magnetic Field Laboratory have successfully tested a groundbreaking new magnet design that could literally shed new light on nanoscience and semiconductor research.

When the magnet -- called the Split Florida Helix -- is operational in 2010, scientists will have the ability to direct and scatter laser light at a sample not only down the bore, or center, of the magnet, but also from four ports on the sides of the magnet, while still reaching fields above 25 tesla. By comparison, the highest-field split magnet in the world attains 18 tesla. Tesla is a measurement of the strength of a magnetic field; 1 tesla is equal to 20,000 times the Earths magnetic field.

Magnetism is a critical component of a surprising number of modern technologies, including MRIs and disk drives, and high-field magnets stand beside lasers and microscopes as essential research tools for probing the mysteries of nature. With this new magnet, researchers will be able to expand the scope of their experimental approach, learning more about the intrinsic properties of materials by shining light on crystals from angles not previously available in such high magnetic fields. In materials research, researchers look at which kinds of light are absorbed or reflected at different crystal angles, giving them insight into the fundamental electronic structure of matter......... Posted by: Kevin      Read more         Source

October 31, 2007, 5:13 AM CT

Dinosaur Deaths Outsourced to India?

A series of monumental volcanic eruptions in India may have killed the dinosaurs 65 million years ago, not a meteor impact in the Gulf of Mexico. The eruptions, which created the gigantic Deccan Traps lava beds of India, are now the prime suspect in the most famous and persistent paleontological murder mystery, say researchers who have conducted a slew of new investigations honing down eruption timing.

"It's the first time we can directly link the main phase of the Deccan Traps to the mass extinction," said Princeton University paleontologist Gerta Keller. The main phase of the Deccan eruptions spewed 80 percent of the lava which spread out for hundreds of miles. It is calculated to have released ten times more climate altering gases into the atmosphere than the nearly concurrent Chicxulub meteor impact, as per volcanologist Vincent Courtillot from the Physique du Globe de Paris.

Keller's crucial link between the eruption and the mass extinction comes in the form of microscopic marine fossils that are known to have evolved immediately after the mysterious mass extinction event. The same telltale fossilized planktonic foraminifera were found at Rajahmundry near the Bay of Bengal, about 1000 kilometers from the center of the Deccan Traps near Mumbai. At Rajahmundry there are two lava "traps" containing four layers of lava each. Between the traps are about nine meters of marine sediments. Those sediments just above the lower trap, which was the mammoth main phase, contain the incriminating microfossils......... Posted by: William      Read more         Source

October 30, 2007, 10:19 PM CT

Most Complex Silicon Phased Array Chip in the World

UC San Diego electrical engineers have developed the world's most complex "phased array" -- or radio frequency integrated circuit. This DARPA-funded advance is expected to find its way into U.S. defense satellite communication and radar systems. In addition, the innovations in this chip design will likely spill over into commercial applications, such as automotive satellite systems for direct broadcast TV, and new methods for high speed wireless data transfer.

"This is the first 16 element phased array chip that can send at 30-50 GHz. The uniformity and low coupling between the elements, the low current consumption and the small size - it is just 3.2 by 2.6 square millimeters - are all unprecedented. As a whole system, there are many many firsts," said Gabriel Rebeiz, the electrical engineering professor from the UCSD Jacobs School of Engineering leading the project. The work was done by two graduate students, Kwang-Jin Koh and Jason May, both at the Electrical and Computer Engineering Department (ECE) at UCSD. Rebeiz presented the new chip at DARPA TEAM Meeting, August 28-29, 2007 in Chicago, Illinois. Additional details of the chip will be submitted to an academic journal later this year.

This chip - the UCSD DARPA Smart Q-Band 4x4 Array Transmitter - is strictly a transmitter. "We are working on a chip that can do a transmit and receive function," said Rebeiz......... Posted by: Kevin      Read more         Source