For nearly a century, electrophoretic deposition (EPD) has been used to coat materials by depositing particles of various substances onto the surfaces of items such as ceramics, metals, polymers, and even living cells. A limitation of EPD is that material can be deposited only across an entire surface and not in specific, predetermined locations. A team of researchers at Lawrence Livermore has overcome this limitation with a new technique called light-directed EPD, which uses photoconductive electrodes and direct-current electric fields to dynamically pattern surface material.
Light-directed EPD allows the buildup of material in targeted areas where the light comes in contact with the photoconductor’s surface, thus enabling the creation of arbitrarily patterned, three-dimensional multimaterial composites over large areas with fine resolution. To create a proof-of-concept logo using the new additive manufacturing process, the researchers first deposited a layer of tungsten nanoparticles on surface areas illuminated through a laser-cut aluminum mask. The mask was then changed, along with the solution of nanoparticles, to deposit alumina ceramic material. In the future, the masks will be replaced by a digitally projected mask for a completely automated deposition system.
Light-directed EPD has the potential to elevate traditional EPD from a single-layer, single-material coating process to a true additive manufacturing technique that allows for unique composites to be formed. For example, void areas can be precisely created in a part to control polymer material behaviors for energy absorption, or such areas can be formed within cellular material to create veins for manufactured organs. “This work represents a large step in advancing electrophoretic deposition as a method of fabricating complex, three-dimensional patterned composites,” says Andrew Pascall, engineer and lead author of the team’s paper published in the April 9, 2014, edition of Advanced Materials.
Contact: Andrew Pascall (925) 423-1926 (pascall1@llnl.gov).
Catalyst, Lawrence Livermore’s latest supercomputer, is available to industry and academia collaborators for testing emergent big data technologies, architectures, and applications. A resource for the National Nuclear Security Administration’s (NNSA’s) Advanced Simulation and Computing (ASC) Program, Catalyst represents a major departure from classic simulation-based computing architectures common at Department of Energy laboratories. Its architecture is modified from a Cray® CS300™ high-performance computing cluster. Developed by a partnership with Lawrence Livermore, Cray, and Intel, the machine boasts nearly a terabyte (1012 bytes) of volatile and nonvolatile (NVRAM, or flash) memory per compute node, creating more than 300 terabytes of system memory. The 150-teraflops (trillion floating-point operations per second) cluster runs the NNSA-funded Tri-Lab Open Source Software, or TOSS, which provides a common user environment across NNSA tri-lab clusters (Los Alamos, Sandia, and Lawrence Livermore national laboratories).
Catalyst’s novel architecture opens new opportunities to combine floating-point focused capability with data analysis in one system, providing insights into the technologies the ASC Program will require over the next decade to meet mission needs in high-performance simulation and big data computing. The broad range of big data problems Catalyst is well suited to address includes bioinformatics, business analytics, graph networks, machine learning, and natural language processing.
“Our purpose is to use Catalyst as a test bed to develop optimization strategies for data-intensive computing,” says Fred Streitz, director of Livermore’s High Performance Computing Innovation Center, which manages private sector access to the system. “We believe that advancing big data technology is a key to accelerating the innovation that underpins our economic vitality and global competitiveness.”
Contact: Fred Streitz (925) 423-3236 (streitz1@llnl.gov).
Each year, the Laboratory releases energy flowcharts that illustrate the source and amount of energy consumed by the nation. According to the most recent energy flowcharts, use of renewable, fossil, and nuclear energy increased in 2013.
Wind energy continued to grow steadily, increasing 18 percent from 1.36 quadrillion British thermal units, or quads, in 2012 to 1.6 quads in 2013. New wind farms continue to come online with bigger, more efficient turbines. Also, the transportation sector used more renewable energy, specifically biomass that is converted to ethanol. Natural gas prices rose slightly in 2013, reversing some of the recent shift from coal to gas in the electricity production sector. Overall, natural gas consumption increased by 0.6 quads. Losses in the electricity sector were more than offset by increased gas use in the residential, commercial, and industrial sectors. “2013 was a cold winter,” says A. J. Simon, group leader for Energy at Lawrence Livermore. “We expect to see continued high gas consumption in 2014 due to another tough winter on the East Coast.” Petroleum use also increased last year. With oil prices remaining relatively constant, this increase was likely due to the nation’s modest economic expansion. Finally, nuclear energy use was greater in 2013. Simon says, “It’s likely fewer reactors were down last year for refueling than in previous years.”
The majority of energy consumption in 2013 was for electricity generation (38.1 quads), followed by the transportation, industrial, residential, and commercial sectors. Energy use in the residential, commercial, and industrial sectors all increased slightly. Overall, Americans used 2.3 quads more in 2013 than the previous year.
Contact: A. J. Simon (925) 422-9862 (simon19@llnl.gov).