Rare Earth New Band Magnetism
MATERIALS – New band magnetism . . .
Rare earth elements vital to electric and hybrid vehicles and numerous other
energy technologies could one day be replaced at least in part by compounds of
heavy transition elements, a team of researchers has discovered.
This finding goes against
conventional wisdom that high performance magnets require rare earth elements
mixed with “first row” light transition elements.
“We found that two second row
compounds have extraordinary unanticipated high magnetic ordering temperatures,
in one case in excess of 750 degrees Celsius, based solely on heavy second row
transition element technetium,” said co-author David Singh of Oak Ridge National
Theoretical work done at ORNL
explains this as band magnetism. These findings have been published in Physical
Review Letters and the Journal of the American Chemical Society.
MATERIALS – Moving toward nanorobots
. . .
Nanoscale robots that can flow through blood or repair complex electronics may
yet be a possibility with the help of a new strategy developed at Oak Ridge
National Laboratory. Although devices such as computer processors can
effectively handle electrical signals at the length scale of 10 nanometers,
achieving motion at the nanoscale has remained elusive. “If we want to conquer
the nanoscale, we need efficient ways to convert electrical signals to
mechanical signals on comparable length scales,” said ORNL’s Sergei Kalinin,
co-author of a paper published in Nano Letters. The paper outlines an approach
for nanoscale motion that takes advantage of the metal insulator transition in
vanadium dioxide. In the work led by ORNL’s Alexander Tselev, the researchers
elicited mechanical motion in their system by applying current to vanadium
dioxide nanowires to observe the interplay between current flow, phase
transformations and mechanical motion.
ENERGY – Boost for industry . . .
Eliminating barriers to energy efficiency of U.S. industry is the focus of a new
report commissioned by the Department of Energy and performed by Georgia
Institute of Technology and Oak Ridge National Laboratory. As the consumer of
about one-third of the nation’s energy, the industrial sector presents a
significant opportunity to save energy, according to the report, “Making
Industry Part of the Climate Solution.” The team, led by Marilyn Brown of
Georgia Tech, evaluated seven federal policy options designed to promote
industry energy efficiency and looked specifically at benefit-to-cost metrics as
well as air pollution and other benefits. The researchers found that each of the
policy options is feasible and applicable and could provide incentives for
industry to become more efficient, thereby improving competitiveness in the
global marketplace. The 299-page report is available at http://www.ornl.gov/sci/ees/etsd/btric/pdfs/Making%20Industry%20Part%20of%20Climate%20Solution_6-7-11.pdf.
CHEMISTRY – Clean energy production . . .
Enterprises from energy production to environmental cleanup depend on chemistry.
A multi-institutional team has generated 70 publications in three years to
demonstrate the prodigious scientific output of the world’s fastest simulations
exploring a continuum from chemistry to materials science. Many have graced the
covers of prestigious journals and dealt with topics from production of hydrogen
for clean energy to development of graphene nanoribbons for power delivery. “Our
long-term goal is enabling the design of new generations of clean and
sustainable technologies to produce, transmit, and store energy,” said team
leader Robert Harrison, a computational chemist at Oak Ridge National Laboratory
and the University of Tennessee who directs the Joint Institute for
Computational Sciences, a partnership between the two organizations. Through the
Innovative and Novel Computational Impact on Theory and Experiment program, the
researchers have been awarded more than 100 million processor hours since 2008.
At the Oak Ridge Leadership Computing Facility, they calculate the electronic
structures of large molecules and surfaces. The findings inform the development
of processes, such as biomass conversion and fuel combustion, and products, such
as batteries, fuel cells and capacitors.
COMPUTATIONAL CHEMISTRY – Converting biomass . . .
When converting corn into ethanol, a lot of lignin and cellulosic material is
left over. We could get energy out of the remains and turn them into other
useful chemicals—if only we had controllable, efficient processes. To improve
those processes, computational chemist Ariana Beste and experimental chemist A.C.
Buchanan, both of Oak Ridge National Laboratory, explore thermochemical
degradation of plant materials. They study how molecular structures influence
networks of chemical reactions. The rate of a reaction depends on the height of
energy barriers along paths between reactants and products and the fraction of
molecules with enough energy to hurdle those barriers. One chemical reaction may
lead to half a dozen products. Favoring a path that results in a specific
product may necessitate understanding a hundred reaction paths. Petascale
simulations on ORNL’s Jaguar supercomputer can quickly calculate the proportion
of molecules with the requisites for a specific reaction—a herculean statistical
challenge. Calculating which bonds between atoms in a molecule have the lowest
energies, for example, reveals the optimal shape for a molecule to assume. That
knowledge can speed design of processes faster than do trial and error or expert
Oak Ridge National Laboratory
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