- Number 380 |
- January 21, 2013
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Jefferson Lab engineers help space chamber reach cold target at unprecedented efficiency
As the U.S. sweated through its warmest year on record outside, a testing chamber at NASA Johnson Space Center in Houston reached its coldest temperatures yet on the inside, cooled by one of the world's most efficient cryogenic refrigeration systems.
Designed by members of the Cryogenics group at the Department of Energy's Jefferson Lab, the system reached its target temperature of 20 Kelvin, about -424 degrees F, for the first time in May 2012 and again during commissioning tests in late August. It reached its target temperature in just over a day and maintains a steady temperature with less than a tenth of a degree in variation over a load temperature range of 16 to 330 Kelvin, all with no loss of helium and using half the liquid nitrogen than comparable systems. But what is even more remarkable is its ability to maintain design efficiency down to a third of its maximum load. -
An unexpected pairing of frustrated molecules
While their shapes frustrate traditional bonding, two unreactive molecules come together and surround themselves within a solvent cage to create a reactive environment and split hydrogen. Researchers at DOE's Pacific Northwest National Laboratory are revealing the role of the solvent in this process. Splitting a hydrogen molecule into a proton and a hydride ion (H-), known as activating the hydrogen, is vital for sustainable energy production and storage. The pair of molecules is called a frustrated Lewis pair.
"Conventional wisdom says that frustrated Lewis pairs should not be able to activate hydrogen—but they do. We wanted to know why," said Dr. Greg Schenter, a theoretical chemist on this project. -
Disruption mitigation researchers investigate design options
ITER, the world’s first reactor-scale fusion machine, will have a plasma volume more than 10 times that of the next largest tokamak, JET. Plasma disruptions that can occur in a tokamak when the plasma becomes unstable can potentially damage plasma-facing surfaces of the machine. To lessen the impact of high energy plasma disruptions, US ITER is engaged in a global research effort to develop disruption mitigation strategies.
US ITER, managed by DOE's Oak Ridge National Laboratory, will continue working closely with global partners on the ITER disruption mitigation system, as the 2016 deadline for design of the system rapidly approaches. To continue moving R&D forward, an early conceptual design review was supported by US ITER in November. -
Breakthrough iron-based superconductors set new performance records
The road to a sustainably powered future may be paved with super-cold superconductors—remarkable materials that are singularly capable of conducting electric current with zero loss. But strict limits on operating temperature, high costs, and the dampening effects of magnetic fields currently impede widespread adoption. Now, a collaboration led by scientists at DOE’s Brookhaven National Laboratory have created a high performance iron-based superconducting wire that opens new pathways for some of the most essential and energy-intensive technologies in the world.
These custom-grown materials carry tremendous current under exceptionally high magnetic fields—an order of magnitude higher than those found in wind turbines, magnetic resonance imaging (MRI) machines, and even particle accelerators. The results—published online January 8 in the journal Nature Communications—demonstrate a unique layered structure that outperforms competing low-temperature superconducting wires while avoiding the high manufacturing costs associated with high-temperature superconductor (HTS) alternatives. -
Sandia airborne pods seek to trace nuclear bomb's origins
If a nuclear device were to unexpectedly detonate anywhere on Earth, the ensuing effort to find out who made the weapon probably would be led by aircraft rapidly collecting airborne radioactive particles for analysis.
Relatively inexpensive unmanned aerial vehicles (UAVs) — equipped with radiation sensors and specialized debris-samplers — could fly right down the throat of telltale radiation over a broad range of altitudes without exposing a human crew to hazards.
An airborne particulate-collection system developed by DOE's Sandia National Laboratories demonstrated those kinds of capabilities in the blue skies above Grand Forks Air Force Base in Grand Forks, N.D., in late September. Dubbed “Harvester” for obvious reasons, the system “tasted” the atmosphere with two particulate sampling pods. A third pod would provide directional guidance for a real event by following the trail of gamma radiation.
