These are a few of the Laboratory's achievements during 2012 in ST&E.
Atmospheric scientist Benjamin Santer is lead author of a paper published in Proceedings of the National Academy of Sciences describing a 17-organization team's comparison of 20 different computer models to satellite observations, which concludes that tropospheric and stratospheric temperature changes are clearly related to human activities. The new climate model simulations analyzed by the team will form the scientific backbone of the upcoming 5th assessment of the Intergovernmental Panel on Climate Change, due in 2014. Both satellite observations and simulations show that the lower stratosphere cooled markedly over the past 33 years, primarily in response to the human-caused depletion of stratospheric ozone. The observations and model simulations also show a common pattern of large-scale warming of the lower troposphere, with the greatest warming over the Arctic and muted warming over Antarctica. Tropospheric warming is mainly driven by human-caused increases in well-mixed greenhouse gases. "It's very unlikely that purely natural causes can explain these distinctive patterns of temperature change," said Ben. The figure is a screen capture of an animation depicting atmospheric temperature change in different atmospheric layers over a 32-year period (1979–2011) as simulated with a model (left) and based on satellite observations (right). Read More »
In a paper published in the December 2012 issue of Modelling and Simulation in Materials Science and Engineering and featured on the issue's cover, former LLNL postdoc Alex Stukowski (now at Technische Universität Darmstadt, Germany) and LLNL colleagues present an automated algorithm that extracts dislocation information from the molecular dynamics simulations of crystalline materials, whose properties are greatly determined by the dislocation that occurs at grain boundaries and other crystal interfaces. The computationally efficient algorithm identifies and indexes dislocations in crystal lattices and interfaces and outputs a representation of the dislocation networks in a form commensurate with classical dislocation theory. The new technique also presents clear advantages over traditional manual methods, which are error-prone, laborious, and, in many cases, unfeasible. Read More »
In a key discovery, a team of LLNL researchers has developed the first plastic material capable of efficiently distinguishing neutrons from gamma rays, something not thought possible for the past five decades or so. As a result, the new technology could assist in detecting nuclear substances such as plutonium and uranium that might be used in improvised nuclear devices by terrorists and could help in detecting neutrons in major scientific projects. With the material's low cost, huge plastic sheets could be formed easily into dramatically larger surface areas than other neutron detectors currently used and could aid in the protection of ports, stadiums and other large facilities.
"It has been established opinion since the 1950s that organic crystals and liquid scintillators can work for detecting neutrons, but that plastics are not suitable for neutron detection," said Natalia Zaitseva, an LLNL materials scientist. Scintillators are special materials that light up when excited by ionizing radiation. Read More »
The Laboratory has licensed a microbial detection array technology to a St. Louis, Mo.-based company, MOgene LC, a supplier of DNA microarrays and instruments. Known as the Lawrence Livermore Microbial Detection Array (LLMDA), the technology could enable food safety professionals, law enforcement, medical professionals, and others to detect within 24 hours any virus or bacteria that has been sequenced and included among the array's probes.
Developed between October 2007 and February 2008, the LLMDA detects viruses and bacteria with the use of 388,000 probes that fit in a checkerboard pattern in the middle of a one-inch wide, three-inch long glass slide. The current operational version of the LLMDA contains probes that can detect more than 2,200 viruses and more than 900 bacteria. Read More »
Fifteen years of work by the Lawrence Livermore National Laboratory's National Ignition Facility (NIF) team paid off on July 5 with a historic record-breaking laser shot. The NIF laser system of 192 beams delivered more than 500 trillion watts (terawatts or TW) of peak power and 1.85 megajoules (MJ) of ultraviolet laser light to its target. Five hundred terawatts is 1,000 times more power than the United States uses at any instant in time, and 1.85 megajoules of energy is about 100 times what any other laser regularly produces today.
The shot validated NIF's most challenging laser performance specifications set in the late 1990s, when scientists were planning the world's most energetic laser facility. Combining extreme levels of energy and peak power on a target in the NIF is a critical requirement for achieving one of physics' grand challenges — igniting hydrogen fusion fuel in the laboratory and producing more energy than that supplied to the target. Read More »
Sequoia, a world-class IBM BlueGene/Q computer sited at LLNL, is now exploring a broad range of science to "shake out" the machine and fully develop the capabilities it will require to fulfill its national security missions, starting early next year. In this preparatory shakeout operations, researchers from LLNL, Los Alamos, and Sandia National Laboratories are testing Sequoia's power and versatility by exploring such unclassified science as high-energy-density plasmas and the electronic structure of heavy metals.
Once the 20-petaflop system is ready, Sequoia will transition in March 2013 to classified work for the National Nuclear Security Administration's Advanced Simulation and Computing Program — a cornerstone of the nation's stockpile stewardship program — to ensure the safety, security, and effectiveness of the nuclear deterrent without underground testing. Sequoia's mammoth computational power will be used to assess physical weapons systems and provide a more accurate atomic-level understanding of the behavior of materials in the extreme conditions present in a nuclear weapon. Read More »
Four Livermore scientists earned $10 million in funding through the Department of Energy Office of Science Early Career Research Program (ECRP). The five-year awards are designed to bolster the nation's scientific workforce by providing support to exceptional researchers during the crucial early career years, when many scientists do their most formative work. This year, the Office of Science awarded 68 recipients out of a total of 850 proposals. In comparison to other DOE labs, Livermore tied with Oak Ridge and Argonne national laboratories, which all won four awards each.
Celine Bonfils, a climate scientist in the Program for Climate Model Diagnosis and Intercomparison, earned the award for detection and attribution of regional climate change with a focus on the precursors of droughts. "I have been extremely fortunate to work with amazing mentors who believed in me and guided me in my research," Bonfils said. Read More »