A synergistic effort between theory, modeling, computer simulations and experiments at Oak Ridge National Laboratory has demonstrated that oriented fluorescent nanostructures with dramatically enhanced spectral and photophysical properties can be formed from single molecules of semiconducting organic polymers. Semiconductors based on organic materials such as polymers are more suited to a range of practical applications than the more conventional and more inflexible inorganic crystals. Computer models predicted, and laboratory experiments using ink-jet methods confirmed, that dilute polymer solutions organize themselves into compact shapes. Using these techniques with photosensitive materials, ORNL researchers produced nanoparticles with superior optical and electronic "quantum dot" properties that function similarly to light-emitting diodes or transistors. The versatility introduced by the use of organic polymers could result in such future products as electronic paper, luminescent clothing and ever more miniaturized and novel electronic tools and consumer products. [Contact: Bill Cabage 865-574-4399; cabagewh@ornl.gov]
ENERGY -- An untapped resource . . .
Natural methane hydrate deposits offer a potentially vast source of energy, greatly surpassing all known fossil fuel resources, but many questions and challenges remain before these deposits can be tapped. Clathrate hydrates, which consist of a gas molecule surrounded by a cage of water molecules to form an ice-like structure, could in theory also be used to sequester carbon dioxide at the bottom of the ocean. Gas hydrates form at low temperatures and ocean depths of about 500 meters and some scientists see them as an energy source that could provide a transition to a hydrogen-based economy. Of more immediate concern is the hazard these deposits pose to gas and oil drilling operations in deep marine and onshore Arctic settings. Gas kicks, blowouts and fires result when workers penetrate pockets of gas hydrates. Another concern is the effect discharge of methane might have on global warming. A special 17-paper August/September issue of American Mineralogist (http://www.minsocam.org/MSA/AmMin/AmMineral.html), edited by Bryan Chakoumakos of Oak Ridge National Laboratory, offers an in-depth exploration of clathrate hydrates. [Contact: Ron Walli 865-576-0226; wallira@ornl.gov]
TRANSPORTATION -- A road to better highways . . .
Video logging, aerial photography and satellite imaging are giving researchers a better picture of highways and could pave the way to safer and more efficient roads. The focus of the project is a 50-mile stretch of Florida's Interstate 10 between Jacksonville and Tallahassee. Using remote sensing, Demin Xiong of Oak Ridge National Laboratory is gathering extensive information about roadways such as pavement types, road conditions, geography, locations of road signs, traffic signals, center lines, shoulders, medians and lane widths. This information can support many applications, including roadway planning, operations, project management and maintenance. Information technology, particularly Intelligent Transportation Systems, is a key strategy to improve transportation safety and efficiency. The ability to collect data faster, cheaper and more accurately without interruption to normal transportation operations is an essential component to this strategy. Officials with the United States and Florida departments of Transportation, which funded the project, plan to use the information to help solve real-world problems using the latest technologies. Findings and recommendations will be presented at a conference planned for December in Jacksonville. [Contact: Ron Walli 865-576-0226; wallira@ornl.gov]
AIR QUALITY -- Immediate analysis . . .
Instant analysis of the composition of air particulates -- especially vital in an air quality emergency -- is possible with the Aerosol Plasma Spectrometer. Conventional methods used for air monitoring require samples to be taken from a site to a laboratory for analysis, taking anywhere from hours to days before the particulate matter makeup can be determined. The APSPEC, developed by Oak Ridge National Laboratory researcher Mengdawn Cheng, is a high-speed aerosol instrument that measures highly variable properties of airborne particles and immediately provides scientists data regarding the composition of the air particulates. The instrument provides more accurate and concise readings than conventional monitors and can be utilized either on the ground or aboard aircraft. Testing has taken place at the Navy Aviation Depot in San Diego. [Contact: Fred Strohl 865-574-4165; strohlhf@ornl.gov]
CHEMISTRY -- The big squeeze . . .
Studying how glasses react to extreme pressure helps scientists understand how their structure evolves. The research team led by Oak Ridge National Laboratory's Chris Tulk used a newly designed pressure cell to exert 15 GPa (about 2,200,000 pounds per square inch) upon a sample of germania (GeO2) glass. The researchers studied its transformation from a simple structural motif with four oxygen atoms surrounding a germanium atom to a high-density six oxygen atom motif that had never been fully characterized. The researchers used intense beams of X-rays and neutrons for diffraction, along with computer simulation of molecular motions, to study the structural changes in more detail than ever before. This class of glass includes silica (SiO2), an abundant component in the deep Earth, and was thought to undergo an abrupt transformation from low to high density forms. This study shows a more complex slow transformation -- a significant finding with general implications for glass chemistry. The work, which will be featured an upcoming issue of Physical Review Letters, may reveal more about the nature of matter and help seismologists learn more about the Earth's deep interior, where high pressures impact the planet's formation. [Contact: Mike Bradley 865-576-9553; bradleymk@ornl.gov]
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