May 19, 2008, 8:43 PM CT

Researchers Create Superior Polymer

Scientists at Northwestern University and Princeton University have created a new kind of polymer that, because of its extraordinary thermal and mechanical properties, could be used in everything from airplanes to solar cells.

The polymer, a nanocomposite that incorporates functionalized, exfoliated graphene sheets, even conducts electricity, and scientists hope to use that property to eventually create thermally stable, optically transparent conducting polymers.

The results of their research were published May 11 in the online version of Nature Nanotechnology.

Researcher at the McCormick School of Engineering originally teamed up with scientists at Princeton several years ago. McCormick scientists had experience working with polymer nanocomposites, and Princeton scientists had developed a way to exfoliate, or split apart, graphite sheets into very thin single layer, surface-functionalized graphene sheets.

Prior use of graphite in polymers did not garner significantly improved properties since scientists could never get the graphite exfoliated. That meant the graphite was rigid with a low surface area and could only minimally impact properties of the polymer.

But when scientists put even a small amount the newly exfoliated graphene sheets - enough to equal only.05 percent of the material - into the polymer, they found the graphene changed the polymer's thermal stability temperature by 30 degrees. Even adding graphene sheets equal to.01 percent of the material increased stiffness by 33 percent - far beyond what scientists had predicted. The drastic changes in both the thermal stability and the stiffness after adding just a tiny percentage of functionalized graphene indicated that the graphene changes large regions of the polymer radiating out from the nanoparticle surfaces in a percolating network structure......... Posted by: Kevin      Read more         Source

May 19, 2008, 7:51 PM CT

Greener offices make happier employees

According to the 2000 census, Americans office workers spend an average of 52 hours a week at their desks or work stations. Many recent studies on job satisfaction have shown that workers who spend longer hours in office environments, often under artificial light in windowless offices, report reduced job satisfaction and increased stress levels.

How can employers make office environments more conducive to productivity and employee happiness" Try adding some green to your office. Not greenbacksgreen plants! A research study published in the February 2008 issue of HortScience offers employers and corporations some valuable advice for upping levels of employee satisfaction by introducing simple and inexpensive environmental changes.

Dr.Tina Marie (Waliczek) Cade, Associate Professor of Horticulture in the Department of Agriculture at Texas State University, explained that the project was designed to investigate whether employees who worked in offices with windows and views of green spaces and workers who had green plants in their offices perceived greater job satisfaction than employees who did not have access to these environmental components.

Researchers posted a job satisfaction survey on the Internet and administered the survey to office workers in Texas and the Midwest. The survey included questions about job satisfaction, physical work environments, the presence or absence of live interior plants and windows, environmental preferences of the office workers, and demographic information......... Posted by: Tyler      Read more         Source

May 19, 2008, 6:34 PM CT

Mid-Infrared Lasers Show Doubled Efficiency

Scientists at the Center for Quantum Devices at the McCormick School of Engineering at Northwestern University have recently doubled the efficiency of infrared lasers under the U.S. Defense Advanced Research Projects Agency's Efficient Mid-wave Infrared Lasers (EMIL) program.

As these types of lasers become more efficient, they could be used in next-generation laser-based defense systems to fool incoming missile attacks or detect explosives or toxins in the atmosphere. Such lasers could also be used in commercial applications like trace chemical analysis, pollution monitoring, and free space communication.

But first, scientists must find the right laser sources at the right wavelengths. The mid-infrared wavelength range (3 to 5 microns) is particularly useful for defense-based applications, and laser technology in this range has been targeted by the U.S. Defense Advanced Research Projects Agency (DARPA) as a strategic technology. The agency created the EMIL program to develop high efficiency, compact semiconductor laser sources with the hopes of demonstrating both high power (~1 W) and high power efficiency (50 percent) from an individual laser at room temperature. Besides demonstrating a significant energy savings over currently available sources, this technology (the quantum cascade laser) will also be more compact than any other laser technology for this wavelength range and operating temperature, with an active volume that is smaller than a human hair......... Posted by: Kevin      Read more         Source

May 18, 2008, 10:05 PM CT

Nanosoccer Robots in Action in Pittsburgh

Nanosoccer returns to the field later this month, when the National Institute of Standards and Technology (NIST) hosts for the second time the world's most Lilliputian sport. Three student teams will participate in a public exhibition at the 2008 U.S. "RoboCup Open" in Pittsburgh, Pa., May 25 to 27, where miniature "soccer players"-computer-driven robots six times smaller than an amoeba operating on a field the size of a grain of rice-will show off their skills.

The teams from Carnegie-Mellon University (Pittsburgh, Pa.), the U.S. Naval Academy (Annapolis, Md.) and the University of Waterloo (Waterloo, Ontario, Canada) will meet at the Carnegie Science Center in Pittsburgh, Pa., to put their nanobots (nanoscale robots) through their paces. The nanobots will be demonstrating agility, maneuverability, response to computer control and ability to move objects-all tools that future miniaturized mechanized workers will need for tasks such as microsurgery within the human body or the manufacturing of atom-sized components for microscopic electronic devices.

RoboCup is an annual international competition designed to foster innovations and advances in artificial intelligence and intelligent robotics by using the game of soccer as a testing ground. NIST's goal in coordinating competitions between the world's smallest robots is to show the feasibility and accessibility of technologies for fabricating MicroElectroMechanical Systems (MEMS), tiny mechanical devices built onto semiconductor chips and measured in micrometers (millionth of a meter)......... Posted by: Kevin      Read more         Source

May 18, 2008, 9:57 PM CT

Improved Ion Mobility Is Key to New Hydrogen Storage Compound

A materials scientist at the National Institute of Standards and Technology (NIST) has deciphered the structure of a new class of materials that can store relatively large quantities of hydrogen within its crystal structure for later release. The new analysis* may point to a practical hydrogen storage material for automobile fuel cells and similar applications.

The abundant element hydrogen could play a role in replacing carbon-based fuels for transportation in the future, but scientists first must develop a method to store and release large amounts of the highly flammable, odorless invisible gas economically and safely. There are materials that are known to trap relatively large quantities of hydrogen, at normal pressures, but to date they all require heating to fairly high temperatures to release the hydrogen.

Hui Wu, a research associate from the University of Maryland working in a cooperative research program at the NIST Center for Neutron Research, has been investigating a new hydrogen storage compound that mixes lithium amide with lightweight metal hydrides. Lithium amide can hold more than 10 percent of hydrogen by weight, well above the 6 percent target set by the U.S. Department of Energy as a 2010 goal for a hydrogen storage material for transportation. The material absorbs and releases hydrogen reversibly, but both absorbing and releasing the hydrogen requires high temperatures and also produces a toxic byproduct, ammonia......... Posted by: Sarah      Read more         Source

May 15, 2008, 8:18 PM CT

Atmosphere threatened by pollutants entering ocean

A large quantity of nitrogen compounds emitted into the atmosphere by humans through the burning of fossil fuels and the use of nitrogen fertilizers enters the oceans and may lead to the removal of some carbon dioxide from the atmosphere, concluded a team of international researchers led by Texas A&M University Distinguished Professor of Oceanography and Atmospheric Sciences Robert Duce.

The team of 30 experts from institutions around the world presented its conclusions in the current issue of the journal Science.

Human-caused atmospheric nitrogen compounds are carried by wind and deposited into the ocean, where they act as a fertilizer and lead to increased production of marine plant life. The increase in plant life causes more carbon dioxide to be drawn from the atmosphere into the ocean. This process results in the removal of about 10 percent of the human-caused carbon dioxide in the atmosphere, thus potentially reducing the climate warming potential, as per the teams paper.

However, some of the nitrogen deposited in the ocean is re-processed to form another nitrogen compound called nitrous oxide, which is then released back into the atmosphere from the ocean. Nitrous oxide is a powerful greenhouse gas itself about 300 times more powerful per molecule than carbon dioxide thus cancelling out about two-thirds of the apparent gain from the carbon dioxide removal, Duce explained. But of course, the whole system is so complex that were still rather unsure about what some of the other impacts might be within the ocean, he said......... Posted by: Tyler      Read more         Source

May 15, 2008, 8:09 PM CT

El Nio may have been factor in Magellan's Pacific voyage

A new paper by North Carolina State University archaeologist Dr. Scott Fitzpatrick shows that Ferdinand Magellans historic circumnavigation of the globe was likely influenced in large part by unusual weather conditions including what we now know as El Nio which eased his passage across the Pacific Ocean, but ultimately led him over a thousand miles from his intended destination.

Magellan set out from Spain in 1519 with hopes of claiming the wealth of the Spice Islands, or Moluccas, for the Spanish. Two years later the explorer claimed the first European contact with a Pacific island culture when he landed on Guam 1,500 miles north of the Spice Islands. How did he make it that far" And how did he miss the Spice Islands by that much".

The paper, co-authored by Fitzpatrick and University of Calgary researcher Dr. Richard Callaghan, uses computer modeling and historical data to determine the role oceanographic conditions may have played in Magellans smooth voyage after rounding the notorious Cape Horn at the southernmost tip of South America and in his decision to sail far north of the Spice Islands which Magellan knew lay along the equator.

The paper, Magellans Crossing of the Pacific: Using Computer Simulations to Examine Oceanographic Effects on One of the Worlds Greatest Voyages, was highlighted in the Random Samples section of the May 16 issue of Science, and would be reported in the Journal of Pacific History in August......... Posted by: Tyler      Read more         Source

May 15, 2008, 7:30 PM CT

Gravity-defying bird beak mystery

As Charles Darwin showed nearly 150 years ago, bird beaks are exquisitely adapted to the birds' feeding strategy. A team of MIT mathematicians and engineers has now explained exactly how some shorebirds use their long, thin beaks to defy gravity and transport food into their mouths.

The phalarope, commonly found in western North America, takes advantage of surface interactions between its beak and water droplets to propel bits of food from the tip of its long beak to its mouth, the research team reports in the May 16 issue of Science.

These surface interactions depend on the chemical properties of the liquid involved, so phalaropes and about 20 other birds species that use this mechanism are extremely sensitive to anything that contaminates the water surface, especially detergents or oil.

"Some species rely exclusively on this feeding mechanism, and so are extremely vulnerable to oil spills," said John Bush, MIT associate professor of applied mathematics and senior author of the paper.

Wildlife biologists have long noted the unusual feeding behavior of phalaropes, which spin in circles on the water, creating a vortex that sweeps small crustaceans up to the surface, just like tea leaves in a swirling tea cup.

The birds peck at the surface, picking up millimetric droplets of water with their prey trapped inside. Since the birds point their beaks downward during the feeding process, gravity must be overcome to get those droplets from the tip of the bird's long beak to its mouth. Until now, scientists have been puzzled as to how that happens......... Posted by: Ashley      Read more         Source

May 14, 2008, 9:04 PM CT

Scientists aim to unlock deep-sea 'secrets' of Earth's crust

Researchers from Durham University will use robots to explore the depths of the Atlantic Ocean to study the growth of underwater volcanoes that build the Earths crust.

The Durham experts will lead an international team of 12 researchers aboard Britains Royal Research Ship James Cook which will set sail from Ponta Delgada, San Miguel, in the Azores on Friday, May 23.

During the five-week expedition they will use explorer robots to map individual volcanoes on the Mid-Atlantic Ridge tectonic plate boundary which effectively runs down the centre of the Atlantic Ocean - almost two miles (3km) below the surface of the sea.

They will then use another robot, called ISIS, to collect rock samples from the volcanoes which will be dated using various techniques to shed more light on the timescales behind the growth of the Earths crust and the related tectonic plates.

As tectonic plates formations that make up the Earths shell - are pulled apart by forces in the Earth, rocks deep down in the mantle are pulled up to fill the gap left behind. As the rocks rise they start to melt and form thousands of volcanoes on the sea floor which eventually cluster into giant ridges.

The ridges along the Mid-Atlantic Ridge plate boundary are each about the size of the Malvern Hills and contain hundreds of individual volcanoes......... Posted by: Tyler      Read more         Source

May 14, 2008, 8:58 PM CT

Held together by metal-metal bonds

Chinese scientists have recently made a "golden crown" with a diameter of only a few nanometers. It is a large ring-shaped molecule containing 36 gold atoms. The lords of the ring, a team of scientists from the Universities of Beijing, Hong Kong, and Nanjing report their unusual compound in the journal Angewandte Chemie: the molecular ring structure is held together exclusively by gold-gold bonds and is thus the largest ring system made of gold atoms produced to date.

Large molecular rings have fascinated chemists for over 40 years-ever since the discovery of crown ethers in 1967. The pioneers in this area, C. J. Pederson, J.-M. Lehn, and D. J. Cram received the Nobel Prize in Chemistry for their discovery in 1987. In the meantime, large molecular ring systems have played an important role in the search for new functional materials and in nanotechnology. The synthesis of ring systems held together exclusively by metal-metal bonds has remained a challenge.

Small rings made of positively charged gold atoms have been know for some time, but only recently could the Chinese team make a ring containing 16 gold atoms. Now, the researchers, led by Shu-Yan Yu, Yi-Zhi Li, and Vivian Wing-Wah Yam, have introduced a new representative of this class of compounds, the biggest gold ring to date that is held together by means of gold-gold bonds: a ring system containing 36 univalent gold atoms......... Posted by: Sarah      Read more         Source