- Number 410 |
- March 31, 2014
Scientists at DOE's Ames Laboratory are revealing the mysteries of new materials using ultra-fast laser spectroscopy, similar to high-speed photography where many quick images reveal subtle movements and changes inside the materials. Seeing these dynamics is one emerging strategy to better understanding how new materials work, so that we can use them to enable new energy technologies.
Physicist Jigang Wang and his colleagues recently used ultra-fast laser spectroscopy to examine and explain the mysterious electronic properties of iron-based superconductors.
It takes dedication and perseverance to solve a mystery that has been around for 50 years. Just ask Reinhard Schumacher, a professor of physics at Carnegie Mellon University. He and his colleagues analyzed data from an experiment conducted at DOE's Thomas Jefferson National Accelerator Facility to finally pin down two key characteristics that had never been measured before of an elusive particle, the Lambda(1405).
But that wasn't the original goal of the experiment, nor is it the first result to be announced from the data. Rather, this result was announced in the 18th paper to be published from this one experiment.
That doesn't bother Schumacher at all. In fact, it's a source of pride for how well he and his colleagues in the CLAS collaboration planned and carried out the measurements back in 2004 in Jefferson Lab's Experimental Hall B. The original experiment was the idea of researchers from the Istituto Nazionale di Fisica Nucleare in Italy who were pursuing different goals. The data from the experiment has been remarkably fertile, especially in terms of providing these first measurements of the Lambda(1405).
Overseas dust increases the Sierra Nevada Mountains snowpack and atmospheric rivers cause it to rapidly melt, according to scientists at DOE's Pacific Northwest National Laboratory and their colleagues. The team reached this finding by modeling two cloud conditions under the influence of atmospheric rivers, narrow bands of moisture transported from the tropics, during a field experiment called CalWater 2011. Atmospheric rivers are the primary cause of flooding in California by dumping rain and accelerating snowmelt in the mountainous terrain. Dust blown in possibly from Asia and Africa increases the formation of snow in winter clouds over California and increases rain- and snowfall by 10 to 20 percent. However, local pollution from California cities and the Central Valley has little impact on snowfall. Further, local pollution's influence on rain from warm clouds heavily depends on cloud conditions and the strength of a low level jet, often associated with atmospheric rivers, that blows parallel to the Sierra Nevada Mountains.
“We used observational data captured in the clouds and on the surface to better understand how cloud ice forms in the presence of dust particles and simulated this process in models,” said Dr. Jiwen Fan, PNNL atmospheric scientist and lead author of the study. “We compared the impacts of long-range transported dust to local pollution from coastal cities and the Central Valley on cold-season precipitation in contrasting cloud and meteorological conditions.”