- Number 363 |
- May 21, 2012
For more than a decade, scientists have tried to improve lithium-based batteries by replacing the graphite in one terminal with silicon, which can store 10 times more charge. But after just a few charge/discharge cycles, the silicon structure would crack and crumble, rendering the battery useless.
Now a team led by materials scientist Yi Cui of Stanford University and SLAC National Accelerator Laboratory has found a solution: a cleverly designed double-walled nanostructure that lasts more than 6,000 cycles, far more than needed by electric vehicles or mobile electronics.
Physicists have discovered a possible solution to a mystery that has long baffled researchers working to harness fusion. If confirmed by experiment, the finding could help scientists eliminate a major impediment to the development of fusion as a clean and abundant source of energy for producing electric power.
An in-depth analysis by scientists from DOE’s Princeton Plasma Physics Laboratory (PPPL) zeroed in on tiny, bubble-like islands that appear in the hot, charged gases—or plasmas—during experiments. These minute islands collect impurities that cool the plasma. And it is these islands, the scientists report in the April 20 issue of Physical Review Letters, that are at the root of a long-standing problem known as the “density limit” that can prevent fusion reactors from operating at maximum efficiency.
A carbon nanotube sponge that can soak up oil in water with unparalleled efficiency has been developed with help from computational simulations performed at DOE's Oak Ridge National Laboratory.
Carbon nanotubes, which consist of atom-thick sheets of carbon rolled into cylinders, have captured scientific attention in recent decades because of their high strength, potential high conductivity and light weight. But producing nanotubes in bulk for specialized applications was often limited by difficulties in controlling the growth process as well as dispersing and sorting the produced nanotubes.
In an important step toward engineering bacteria to produce biofuel, scientists at DOE’s Pacific Northwest National Laboratory have developed one of the first global models for the nitrogen-fixing photosynthetic cyanobacterium Cyanothece sp. ATCC 51142. This round, bluish-green bacteria could produce biofuel because it uses sunlight to create sugars and other molecules, the precursors for fuel. The cyanobacterium also grows relatively rapidly, tolerates extreme environments, and can accumulate high amounts of the desired compounds. But only a few models have been developed for investigating cyanobacterium because they are so complex.
The new global model describes the cyanobacterium’s complete metabolism, not just isolated pathways. “The model details how carbon and energy are distributed throughout the cell for photosynthesis and respiration,” said Dr. Alex Beliaev, a microbiologist at PNNL. “Developing a computational model brings us closer to a systems-level understanding of the metabolism of photoautrophs such as Cyanothece, putting metabolic engineering of these organisms within reach.”
Researchers interested in the perennial grass switchgrass, considered a prospective biofuels feedstock by the DOE, have found the genome challenging to assemble because it has multiple copies of its chromosomes. The DOE Joint Genome Institute (JGI), in an international partnership that includes the BioEnergy Science Center and the Joint BioEnergy Institute, two of the three DOE Bioenergy Research Centers, has sequenced plant genomes of related candidate bioenergy crops such as sorghum and the model grass Brachypodium.