| January 15, 2007
New way to spin up pulsars
This visualization shows the progression of spiral formation in a supernova, which eventually results in a pulsar's spin. The darkest portion of the accretion shock denotes the front edge of the wave as it rotates around the supernova's center. Three-dimensional computer models are the only models that show this effect. This 3D model of pulsar formation was performed at DOE's Leadership Computing Facility at Oak Ridge National Laboratory.
A team of scientists using supercomputers at DOE's Oak Ridge National Laboratory has discovered the first plausible explanation for a pulsar's spin that fits the observations made by astronomers. According to three-dimensional simulations they performed at the Leadership Computing Facility, located at ORNL, the spin of a pulsar is determined not by the spin of the original star, but by the shock wave created when the star's massive iron core collapses. That shock wave is inherently unstable, a discovery the team made in 2002. The instability creates two counter-rotating flows. The asymmetrical flows establish a "sloshing" motion that, in the complex 3-D models, accounts for the pulsars observed spin velocities from once every 15 to 300 milliseconds, which is much slower than previous models predicted.
[Leo Williams, 865/574-8891,
Plant a tree and save the earth?
Can planting a tree stop the sea level from rising, the ice caps from melting and hurricanes from intensifying? A new study says that it depends on where the trees are planted. It cautions that new forests in mid- to high-latitude locations could actually create a net warming. It also confirms the notion that planting more trees in tropical rainforests could help slow down global warming worldwide. In the first study to investigate the combined climate and carbon-cycle effects of large-scale deforestation in a fully interactive three-dimensional climate-carbon model, scientists from DOE's Lawrence Livermore National Laboratory, Carnegie Institution and Université Montpellier II found that global forests actually produce a net warming of the planet. The study provides a holistic view of the deforestation issue. “This is the first comprehensive assessment of the deforestation problem” said Govindasamy Bala, lead author of the research that was presented at the American Geophysical Society annual meeting in San Francisco. The models calculated the carbon/climate interactions and took into account the physical climate effect and the partitioning of the carbon dioxide release from deforestation among land, atmosphere and ocean.
[Anne M. Stark, 925/422-9799,
NREL dedicates new Wind to Hydrogen project
DOE's National Renewable Energy Laboratory and Xcel Energy recently dedicated a new demonstration project that will examine system integration issues with the production hydrogen from wind energy and the compression, storage and use of the hydrogen. Two NREL wind turbines will be connected to devices called electrolyzers, which pass the wind-generated electricity through water to split the liquid into hydrogen and oxygen. The hydrogen can be stored and used later to generate electricity from either an internal combustion engine turning a generator or from a fuel cell. NREL and Xcel are each paying part of the $2 million budget for the two-year project.
[Sarah Barba, 303/275-3023,
NETL develops microreactor for accelerated testing of fuel thermal stability
Researchers on the Defense Fuels Team at DOE's National Energy Technology Laboratory have designed and constructed a microreactor for testing thermal stability of liquid fuel formulations. The research supports the Department of Defense's initiative to develop a single, fully-synthetic, hydrogen-rich fuel capable of powering fuel cells and ground vehicles, aircraft, and ships. The microreactor allows researchers to test fuels under conditions mimicking those encountered over longer periods of time in advanced military aircraft fuel systems. Subsequent analysis of the fuel composition to identify products of oxidation will help determine the ability of the additized fuel to withstand the effects of thermal stress.
[Linda Morton, 304/285-4543,
PNNL plague proteome links proteins to infection
Scientists at DOE's Pacific Northwest National Laboratory have uncovered 176 proteins and likely proteins whose numbers rise and fall according to virulence in Yersinia pestis, the bacterium that caused the infamous Black Death plagues. Fleas are vectors for the disease and can spread it to rodent and human hosts. The Environmental Molecular Sciences Laboratory-based team, with help from collaborators at DOE's Lawrence Livermore National Laboratory, culled the biomarker-candidate proteins by looking at abundance changes in 992 proteins under four different growth conditions of Y. pestis in flea and in mammalian systems. Biomarkers associated with disease progression show promise as detection tools in public health and biodefense, and can guide drug and vaccine designers in their quest to disrupt the microbe's ability to infect. The project was funded by the Department of Homeland Security and published in the Journal of Proteome Research.
[Bill Cannon, 509/375-3732,
Prize-winning theoretical physicist loves his Vegemite
Aussie Native Ross Young keeps a stash of Vegemite handy for taming cravings while puzzling through problems in theoretical nuclear physics.
Ross Young, a postdoctoral researcher in the Theory Center at DOE's Jefferson Lab, received the Harold Woolhouse 2005 prize for the best Ph.D. thesis produced in the University of Adelaide's Faculty of Sciences. According to the citation, Young's thesis, titled "Finite-Range Regularisation of Chiral Effective Field Theory," breaks new ground in connecting supercomputer simulations of QCD to Nature.
"Math has always come easily to me, and my particular interest in science and physics was sparked when I was about 10 years old and my granddad, who wasn't a scientist but read a lot, told me about the theory of relativity. I thought that was just so interesting," Young says.
Young was born in Adelaide, Australia, and received his B.S. and Ph.D. in theoretical physics from the University of Adelaide. "I knew early on that I would do theoretical physics, because I'm definitely not an experimentalist. I couldn't take measurements. I couldn't sit there turning knobs. I wanted to know what the theories were," he says.
While working on his Ph.D., Young prepared 23 refereed journal publications, of which three were published in Physical Review Letters. Young arrived at Jefferson Lab in October 2004.
"I love being here, where the work is actually done. I finally am getting to see theory matching up with real work, and I'm finding meaning in all that I'm doing. It's great to be able to talk to people about how it all inter-relates."
With just one more year left in his postdoc, Young is optimistic about the future. "It's time for me to start applying for positions. The only thing I'm sure of is that I want to stay in physics. I'll just keep doing what's comfortable and interesting for me and see where it leads.".
Submitted by DOE's