March 19, 2010, 7:28 AM CT

Designer nanomaterials on demand

Composites are combinations of materials that produce properties inaccessible in any one material. A classic example of a composite is fiberglass - plastic fibers woven with glass to add strength to hockey sticks or the hull of a boat. Unlike the well-established techniques for producing fiberglass and other macroscale composites, however, there aren't general schemes available for making nanoscale composites.

Now, scientists at Berkeley Lab's Molecular Foundry, in collaboration with researcher at the University of California, Berkeley, have shown how nanocomposites with desired properties can be designed and fabricated by first assembling nanocrystals and nanorods coated with short organic molecules, called ligands. These ligands are then replaced with clusters of metal chalcogenides, such as copper sulfide. As a result, the clusters link to the nanocrystal or nanorod building blocks and help create a stable nanocomposite. The team has applied this scheme to more than 20 different combinations of materials, including close-packed nanocrystal spheres for thermoelectric materials and vertically aligned nanorods for solar cells.

"We're just starting to understand how combining materials on the nanoscale can open up new possibilities for electronic properties and efficient energy technologies," said Delia Milliron, Director of the Inorganic Nanostructures Facility at the Molecular Foundry. "This new process for fabricating inorganic nanocomposites gives us unprecedented ability to tune composition and control morphology"......... Posted by: Kevin      Read more         Source

March 17, 2010, 7:54 PM CT

Solving hydrogen storage issues

Graphenecarbon formed into sheets a single atom thicknow may be a promising base material for capturing hydrogen, as per recent research* at the National Institute of Standards and Technology (NIST) and the University of Pennsylvania. The findings suggest stacks of graphene layers could potentially store hydrogen safely for use in fuel cells and other applications.

Graphene has become something of a celebrity material in recent years due to its conductive, thermal and optical properties, which could make it useful in a range of sensors and semiconductor devices. The material does not store hydrogen well in its original form, as per a team of researchers studying it at the NIST Center for Neutron Research. But if oxidized graphene sheets are stacked atop one another like the decks of a multilevel parking lot, connected by molecules that both link the layers to one another and maintain space between them, the resulting graphene-oxide framework (GOF) can accumulate hydrogen in greater quantities.

Inspired to create GOFs by the metal-organic frameworks that are also under scrutiny for hydrogen storage, the team is just beginning to uncover the new structures' properties. "No one else has ever made GOFs, to the best of our knowledge," says NIST theorist Taner Yildirim. "What we have found so far, though, indicates GOFs can hold at least a hundred times more hydrogen molecules than ordinary graphene oxide does. The easy synthesis, low cost and non-toxicity of graphene make this material a promising candidate for gas storage applications"......... Posted by: Sarah      Read more         Source

March 17, 2010, 7:53 PM CT

Turning proteins into glass

uke University scientists have devised a method to dry and preserve proteins in a glassified form that seems to retain the molecules' properties as workhorses of biology.

They are exploring whether their glassification technique could bring about protein-based drugs that are cheaper to make and easier to deliver than current techniques which render proteins into freeze dried powders to preserve them.

Duke engineer and chemist David Needham describes this glassification process as "molecular water surgery" because it removes virtually all the water from around a dissolved protein by almost magically pulling the water into a second solvent.

"It's like a sponge sucking water off a counter," said Needham, a professor of mechanical engineering and materials science at Duke's Pratt School of Engineering, who has formed a company called Biogyali ("gyali" means glass in Greek) to develop the innovation. That firm has also applied to patent the idea of turning proteins into tiny glass beads at room temperature for drug delivery systems.

A report by Needham, graduate student Deborah Rickard and former graduate student P. Brent Duncan online in the Biophysical Journal describes how his team carefully controlled water removal during glassification by releasing single tiny droplets of water-dissolved protein into the organic solvent decanol with a micropipette. (View the abstract here: http://tinyurl.com/yfq9yk3)......... Posted by: Kevin      Read more         Source

March 17, 2010, 7:47 PM CT

Prescribed burns may reduce carbon footprint

The use of prescribed burns to manage western forests may help the United States reduce its carbon footprint.

Results of a newly released study find that such burns, often used by forest managers to reduce underbrush and protect bigger trees, release substantially less carbon dioxide emissions than wildfires of the same size.

"It appears that prescribed burns can be an important piece of a climate change strategy," says Christine Wiedinmyer, a scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and main author of the newly released study.

"If we reintroduce fires into our ecosystems, we appears to be able to protect larger trees and significantly reduce the amount of carbon released into the atmosphere by major wildfires".

The research results are published this week in the journal Environmental Science & Technology The study was funded by the National Science Foundation (NSF), NCAR's sponsor.

Drawing on satellite observations and computer models of emissions, researchers concluded that widespread prescribed burns can reduce fire emissions of carbon dioxide in the West by an average of 18 to 25 percent, and by as much as 60 percent in certain forest systems.

Wildfires often consume large trees that store significant amounts of carbon, as per Steve Nelson, NSF program director for NCAR......... Posted by: Tyler      Read more         Source

March 15, 2010, 8:52 PM CT

Bracket seedings irrelevant

For the average college basketball fan looking for an edge in a March Madness office pool, a University of Illinois expert in statistics and data analysis has some advice on how to pick winners: After the Sweet Sixteen round of play, ignore a team's seeding, which is a statistically insignificant predictor of a team's chances of winning.

As per Sheldon H. Jacobson, a professor of computer science and the director of the simulation and optimization laboratory at Illinois, picking the higher-seeded team to beat a lower-seeded opponent commonly works only in the first three rounds of the tournament. Once the tournament enters the Elite Eight round, a team's seed in the tournament is irrelevant.

"In the Sweet Sixteen round, the rankings still hold - but just barely," Jacobson said. "From the Elite Eight round and onward, you might as well pick names out of a hat".

Jacobson, who along with graduate student Douglas M. King wrote an article titled "Seeding in the NCAA Men's Basketball Tournament: When is a Higher Seed Better?" reported in the Journal of Gambling Business and Economics, said the impetus of the study was to see if a team's seeding was a good predictor of how far the team ultimately would go in the Big Dance.

"You would expect once you get deeper in the tournament that the higher seeds would continue to dominate," Jacobson said......... Posted by: Kevin      Read more         Source

March 12, 2010, 8:04 AM CT

Aquatic 'dead zones' contributing to climate change

The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than just local waters. In the March 12 edition of the journal Science, University of Maryland Center for Environmental Science oceanographer Dr. Lou Codispoti explains that the increased amount of nitrous oxide (N2O) produced in low-oxygen (hypoxic) waters can elevate concentrations in the atmosphere, further exacerbating the impacts of global warming and contributing to ozone "holes" that cause an increase in our exposure to harmful UV radiation.

"As the volume of hypoxic waters move towards the sea surface and expands along our coasts, their ability to produce the greenhouse gas nitrous oxide increases," explains Dr. Codispoti of the UMCES Horn Point Laboratory. "With low-oxygen waters currently producing about half of the ocean's net nitrous oxide, we could see an additional significant atmospheric increase if these 'dead zones' continue to expand".

Eventhough present in minute concentrations in Earth's atmosphere, nitrous oxide is a highly potent greenhouse gas and is becoming a key factor in stratospheric ozone destruction. For the past 400,000 years, changes in atmospheric N2O appear to have roughly paralleled changes in carbon dioxide CO2 and have had modest impacts on climate, but this may change. Just as human activities appears to be causing an unprecedented rise in the terrestrial N2O sources, marine N2O production may also rise substantially as a result of nutrient pollution, warming waters and ocean acidification. Because the marine environment is a net producer of N2O, much of this production will be lost to the atmosphere, thus further intensifying its climatic impact......... Posted by: Tyler      Read more         Source

March 8, 2010, 9:28 AM CT

New way of producing electricity

A team of researchers at MIT have discovered a previously unknown phenomenon that can cause powerful waves of energy to shoot through minuscule wires known as carbon nanotubes. The discovery could lead to a new way of producing electricity, the scientists say.

The phenomenon, described as thermopower waves, "opens up a new area of energy research, which is rare," says Michael Strano, MIT's Charles and Hilda Roddey Associate Professor of Chemical Engineering, who was the senior author of a paper describing the new findings that appeared in Nature Materials on March 7. The main author was Wonjoon Choi, a doctoral student in mechanical engineering.

Like a collection of flotsam propelled along the surface by waves traveling across the ocean, it turns out that a thermal wave a moving pulse of heat traveling along a microscopic wire can drive electrons along, creating an electrical current.

The key ingredient in the recipe is carbon nanotubes submicroscopic hollow tubes made of a chicken-wire-like lattice of carbon atoms. These tubes, just a few billionths of a meter (nanometers) in diameter, are part of a family of novel carbon molecules, including buckyballs and graphene sheets, that have been the subject of intensive worldwide research over the last two decades......... Posted by: Kevin      Read more         Source

March 8, 2010, 9:10 AM CT

what would nature do?

A recent discovery in understanding how to chemically break down the greenhouse gas carbon dioxide into a useful form opens the doors for researchers to wonder what organism is out there - or could be created - to accomplish the task.

University of Michigan biological chemist Steve Ragsdale, along with research assistant Elizabeth Pierce and researchers led by Fraser Armstrong from the University of Oxford in the U.K., have figured out a way to efficiently turn carbon dioxide into carbon monoxide using visible light, like sunlight.

The results are published in the recent online edition of the Journal of the American Chemical Society.

Not only is it a demonstration that an abundant compound can be converted into a commercially useful compound with considerably less energy input than current methods, it also is a method not so different from what organisms regularly do.

"This is a first step in showing it's possible, and imagine microbes doing something similar," Ragsdale said. "I don't know of any organism that uses light energy to activate carbon dioxide and reduce it to carbon monoxide, but I can imagine either finding an organism that can do it, or genetically engineering one to channel light energy to coax it to do that."

In this collaboration between Ann Arbor and Oxford, Ragsdale's laboratory at the U-M Medical School does the biochemistry and microbiology experiments and Armstrong's lab performs the physical- and photochemical applications......... Posted by: Tyler      Read more         Source

March 4, 2010, 9:42 PM CT

For California vintners

"Green" labels do not pack the same wallop for California wines that they do for low-energy appliances, organically grown produce and other environmentally friendly products, but it's not because there's anything wrong with the wine, a new UCLA-led study has observed.

In fact, wines made with organically grown grapes actually rate higher on a widely accepted ranking, said Magali Delmas, a UCLA environmental economist and the study's main author. And these wines tend to command a higher price than their conventionally produced counterparts, so long as wineries don't use the word "organic" on their labels.

But when wineries do use eco-labels, prices plummet.

"You've heard of the French paradox?" quipped Delmas, associate professor of management at UCLA's Institute of the Environment and the UCLA Anderson School of Management. "Well, this is the American version. You'd expect anything with an eco-label to command a higher price, but that's just not the case with California wine".

The anomaly points to a marketing conundrum for environmentally friendly vintners and a buying opportunity for oenophiles, say Delmas and her co-author, Laura E. Grant, a Ph.D. candidate in environmental science and management at the University of California, Santa Barbara......... Posted by: Tyler      Read more         Source

March 4, 2010, 9:40 PM CT

Exotic Antimatter Detected

An international team of researchers studying high-energy collisions of gold ions at the Relativistic Heavy Ion Collider (RHIC), a 2.4-mile-circumference particle accelerator located at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, has published evidence of the most massive antinucleus discovered to date. The new antinucleus, discovered at RHIC's STAR detector, is a negatively charged state of antimatter containing an antiproton, an antineutron, and an anti-Lambda particle. It is also the first antinucleus containing an anti-strange quark. The results will be published online by Science Express on March 4, 2010.

"This experimental discovery may have unprecedented consequences for our view of the world," commented theoretical physicist Horst Stoecker, Vice President of the Helmholtz Association of German National Laboratories. "This antimatter pushes open the door to new dimensions in the nuclear chart - an idea that just a few years ago, would have been viewed as impossible".

The discovery may help elucidate models of neutron stars and opens up exploration of fundamental asymmetries in the early universe.

New nuclear terrain

All terrestrial nuclei are made of protons and neutrons (which in turn contain only up and down quarks). The standard Periodic Table of Elements is arranged as per the number of protons, which determine each element's chemical properties. Physicists use a more complex, three-dimensional chart to also convey information on the number of neutrons, which may change in different isotopes of the same element, and a quantum number known as "strangeness," which depends on the presence of strange quarks (see diagram). Nuclei containing one or more strange quarks are called hypernuclei......... Posted by: Kevin      Read more         Source