MATERIALS -- Monster cutters . . .
Underground rock formations in Atlanta will provide a real-world test for monster disc cutters coated with an iron-based nano-composite developed by a team led by Oak Ridge National Laboratory researchers. The laser-fused composite has resulted in hardness values two to seven times greater than conventional steel, according to Narendra Dahotre of the University of Tennessee/ORNL Joint Center for Advanced Photonics Processing. The coatings are expected to result in up to a 25 percent improvement in energy efficiency, significant reductions in down time and potential improvements in tunnel boring health and safety. This work, which is funded by DOE's Office of Civilian Radioactive Waste Management Program, is part of an effort to improve tunnel boring disc cutters to cut repository tunnels for radioactive material storage. Other partners are Lawrence Livermore National Laboratory and the Colorado School of Mines, where this coated disc cutter was the first in 25 years to survive testing on a hydraulic press that simulates in-field conditions.
ENERGY -- Checking the grid . . .
In the aftermath of last year's Hurricane Katrina, responders looked to the Department of Energy for information on the condition of vital infrastructural resources such as the electric power grid. In the meantime, ORNL researchers, in a partnership with the Tennessee Valley Authority, have developed a visualization system that gives responders a real-time sense of the state of a hurricane-prone region's power grid before, during and after a potentially catastrophic storm or other emergency. The project sprang from the 2003 Northeast blackout, when it was realized that a wider awareness of the status of the power grid would have helped operators react to the crisis. The resulting grid visualization program has been cited as one of the ways the government has enhanced its preparedness for the 2006 hurricane season.
NANOSCIENCE -- Flipping the spin . . .
In a discovery that could contribute to the emerging field of spintronics, scientists at Oak Ridge National Laboratory and the Institute of Physics, Chinese Academy of Science, have demonstrated a way to measure the distance an electron travels in nanoscale materials before its spin is reversed due to scattering. Such measurements are difficult to achieve outright because electrons' spins in a nonmagnetic material rarely flip until they travel a distance many times the size of the device itself. This means that possibly just a small fraction of electrons flip inside a nanoscale device, an attribute that may make electrons' magnetic properties attractive for storage, sensors and, potentially, quantum computing. ORNL theoretical physicist Xiaoguang Zhang used data provided by Chinese colleagues to determine that the measurement could be made by comparing the magnetoresistance of electrons traveling through single and double layer arrangements of an insulating material. The work is to be published in Physical Review Letters.
MATERIALS -- Molecular electronics . . .
Computational simulations aimed at resolving a debate about how molecules bond to metal surfaces could help pave the path to smaller, faster and more powerful electronic devices such as MP3 players. Oak Ridge National Laboratory researchers De-en Jiang, Bobby Sumpter and Sheng Dai are using these simulations to model the bonding between aryl groups " the organic molecules with a flat ring of carbon atoms " and various metal surfaces. Their work helps in predictions for the most likely bonding configurations of molecules on various metal surfaces and helps answer the question of whether the aryl-metal bond is chemical or physical in nature. This is an important distinction for molecular electronics because chemical bonds are ideal electronic connections between molecular circuit elements. The researchers' simulations calculated the electron adsorption energies, which are a measure of the bond strength between the aryl carbon atoms and the metal surface. The calculations were performed using computers at the National Center for Computational Sciences. This research, which was funded by DOE's Office of Basic Energy Sciences, is published in the Journal of the American Chemical Society as a Communication.