These are a few of the Laboratory's recent achievements in ST&E. Updated February 29, 2016
On August 14, 2015, the National Ignition Facility (NIF) fired its 300th laser target shot in fiscal year (FY) 2015, meeting the year’s goal more than six weeks early. In comparison, the facility completed 191 target shots in FY 2014. The NIF is the world’s most energetic laser. Increasing the shot rate has been a top priority for the Inertial Confinement Fusion (ICF) Program and in particular the NIF team. The greater than 50 percent increase in NIF shots from FY 2014 to FY 2015 is a direct result of the implementation of an efficiency study conducted in FY 2014 for the NIF. This 120-day efficiency study was developed in partnership with other NNSA laboratories and drew on best practices at the Z Facility at Sandia National Laboratories and the Omega Laser at the University of Rochester. This study identified more than 80 improvements to equipment and procedures that could lead to reduced time and effort for fielding experiments.
“Demand for experiments at NIF have always exceeded capacity. The impressive work by the team at NIF to produce additional shots has provided important new opportunities for NIF users and increased this unique scientific platform’s contributions to national security,” said Brig. Gen Stephen Davis, USAF, acting deputy administrator for Defense Programs. “I congratulate the NIF team and its many partners for not only meeting, but exceeding the goal.”
“Achieving 300 shots this year enabled so many critical accomplishments: first-of-a-kind dynamic materials data, more efficiently driven ICF capsules, increased opportunities for academic users, new radiation sources for the Department of Defense and acceleration of new diagnostic development,” said Keith LeChien, director of ICF for NNSA.
In a recent series of papers, Livermore scientists examined the role of ablation-front instability and capsule convergence ratio in ignition science experiments at the National Ignition Facility (NIF).1 The papers address different aspects of an “adiabat-shaping” experimental campaign that assessed the effects of ablation-front instability growth versus fuel adiabat (compression) on implosion performance. Two new drives were designed for this mini-campaign: a four-shock adiabat-shaped drive derived from the low-foot, or low initial laser picket, drive used in the National Ignition Campaign, and a three-shock adiabat-shaped drive derived from the high-foot drive that produced the highest neutron yield achieved so far on the NIF.
In papers in Physical Review Letters and Physics of Plasmas, lead authors Dan Casey, Andrew MacPhee, and Vladimir Smalyuk and their colleagues describe a significant improvement in implosion performance using both four-shock and three-shock adiabat-shaped drives. The adiabat-shaped version of the four-shock, low-foot drive “showed a three to ten times improvement in yield compared to similar experiments,” says Casey. With the three-shock drive, the fuel areal density was improved by approximately 25 percent compared to similar high-foot implosions. The work marks an important step forward in the quest for ignition by demonstrating that ablation front growth can be managed while simultaneously achieving high areal density, a necessary requirement for inertial confinement fusion ignition.
1 D. T. Casey, et al., “Improved Performance of High Areal Density Indirect Drive Implosions at the National Ignition Facility using a Four-Shock Adiabat Shaped Drive,” Phys. Rev. Lett. 115, 105001 (2015) http://dx.doi.org/10.1103/PhysRevLett.115.105001.
A.G. MacPhee, et al., “Stabilization of high-compression, indirect-drive inertial confinement fusion implosions using a 4-shock adiabat-shaped drive,” Phys. Plasmas 22, 080702 (2015) http://dx.doi.org/10.1063/1.4928909.
V.A. Smalyuk, et al., “First results of radiation-driven, layered deuterium-tritium implosions with a 3-shock adiabat-shaped drive at the National Ignition Facility,” Phys. Plasmas 22, 080703 (2015) http://dx.doi.org/10.1063/1.4929912.
Livermore researchers are using the National Ignition Facility’s (NIF’s) unique capabilities to study the effects of high pressure and high strain rates on the material strength of tantalum, a strong, ductile metal that serves as an ideal test of scientific understanding of high-pressure material response. A NIF experimental campaign known as TaRT (Tantalum Rayleigh–Taylor) examines tantalum’s material strength, or resistance to deformation, when subjected to up to five megabars (five million atmospheres) of pressure generated by NIF’s lasers. Understanding material strength under high pressure is a key interest in Stockpile Stewardship, Discovery Science, and many other scientific areas.
To study tantalum under such high pressure, the research team created a ramp-compression technique using a reservoir/gap configuration mounted on the side of a large hohlraum about twice the size of normal hohlraums. In order to create the pressure “gently” without shocking and melting the sample, the team uses low-density foams with a sinusoidal ripple pattern. Under pressure, the ripples grow via the Rayleigh–Taylor hydrodynamic instability mechanism. If the material is strong, the ripples will grow less. If the material is not strong, the ripples will grow more. The amount of ripple growth is measured by x-ray radiography. “Strength is directly related to the material’s compressibility,” says Livermore’s Hye-Sook Park. “These experiments continue to advance our physics understanding of material behavior under high pressure and to develop new theory and simulations based on our experimental results.” Collaborators include the Atomic Weapons Establishment, LANL, General Atomics, and the University of Rochester’s Laboratory for Laser Energetics.
A multi-institutional team of scientists fired the 26th and final shot of the Pleiades experimental campaign at the National Ignition Facility (NIF) last month. The campaign has created a new scientific foundation for the study of supersonic radiation flow in astrophysical phenomena and in inertial confinement fusion physics. Pleiades was devised to study how radiation energy propagates through material in the radiation-dominated and diffusive regime. This is a general scientific “problem” created in a range of plasmas, which occur in both astrophysical phenomena and in the laboratory. The team created a laboratory version of the general one-dimensional problem using a half-hohlraum X-ray source, which launched a supersonic and diffusive heat front into a cylinder of foam material. This allowed the researchers to study the basic radiation flow phenomena, as well as constrain the properties of the materials used in a previously inaccessible regime.
The high-temperature hohlraum that was developed for the Pleiades campaign will be a good platform to study radiation flow through other low-density foam media to constrain material properties, says Alastair Moore, LLNL campaign lead. In addition, the Pleiades X-ray drive setup is being applied as part of the Menkar and Cepheus campaigns fielded at NIF by the Atomic Weapons Establishment (AWE) and Los Alamos National Labs (LANL), respectively. The Pleiades platform also was used for a recent performance qualification shot of a new diagnostic.
Nanocrystalline diamond capsules to contain hydrogen fuel are a promising alternative to plastic. They have the potential to reach the higher neutron yields necessary to fusion ignition, according to recent LLNL research. Most inertial confinement fusion (ICF) experiments at LLNL’s National Ignition Facility (NIF) to date have used plastic target capsules, which are bathed in X-rays as the walls of the capsule’s containing vessel, the "hohlraum," absorb and re-radiate laser light. High-density carbon (HDC), a nanocrystalline diamond, has advantages over plastic. In an article published in Physical Review E1, LLNL scientist Steven Ross and colleagues reported on results of five indirect-drive ICF implosion experiments using HDC capsules.
The experiments demonstrated good laser-to-target coupling (about 90 percent) and excellent nuclear performance. An HDC capsule implosion produced a neutron yield about twice that of similarly filled plastic ablator capsules. “These experiments confirm HDC as a viable material for ICF implosions,” the researchers write. This work advances the NIF’s goal of reaching nuclear fusion, a significant energy security mission of LLNL. The research was partially funded by Livermore’s Laboratory Directed Research and Development Program under project 06-ERD-056.
1 J. S. Ross, et al., “High-density carbon capsule experiments on the national ignition facility,” Phys. Rev. E 91, 021101(R), (2015) http://link.aps.org/doi/10.1103/PhysRevE.91.021101.
Differences in the thermal expansion properties of material coatings help explain why some types of coated mirrors in laser systems resist damage better than others, according to LLNL research. In a paper featured1 on the cover of the October 10, 2015, issue of Applied Optics, a team of Livermore researchers and a University of Rochester colleague compared the laser-damage responses of two candidate capping-layer materials, SiO2 and Al2O3, deposited on multilayer structures. According to optical modeling and experimental observations, the laser-particle interactions generate plasma that heats the capping layer, causing damage through mechanical stress. Because the thermal expansion coefficient of SiO2 is 15 times higher than that of Al2O3, thermally induced mechanical stress between the capping layer and the next layer is much lower with SiO2. This result will assist the design of robust protective layers on future mirrors.
High-dielectric-constant multilayer coatings are commonly used on high-reflectivity mirrors for high-peak-power laser systems because of their good resistance to laser-induced damage. However, surface contaminants, such as small particles, often lead to damage upon laser exposure, limiting a mirror’s lifetime and performance. Adding a thin protective “capping” layer on top of the multilayer coatings improves damage resistance. Understanding the mechanism of damage to the capping layer by laser-particle interaction could help improve laser design and capping material selection.2
1 S. R. Qiu, M. A. Norton, R. N. Raman, A. M. Rubenchik, C. D. Boley, A. Rigatti, P. B. Mirkarimi, C. J. Stolz, and M. J. Matthews, “Impact of laser-contaminant interaction on the performance of the protective capping layer of 1-ω high-reflection mirror coatings,” Applied Optics, 54, 29, pp. 8607–8616 (2015) doi: 10.1364/AO.54.008607
2 This work was funded in part by LLNL Laboratory Directed Research and Development (LDRD) project #14-ERD-098.
Livermore research into the use of lasers to repair damaged optics and return them to service is among Laser Focus World’s “top 20 technology picks” for 2015. The research was highlighted in the cover article in the August issue of Laser Focus World, “Processing optics using IR lasers.” In the article, Livermore physicist Ibo Matthews describes how LLNL researchers used COMSOL Multiphysics, a software tool for modeling and simulating physics-based problems, to study techniques for repairing and recycling damaged optics.
Several repair techniques have been developed at Livermore with the aim of extending the useable life of the optics. The simulations included heat transfer in fluids, chemical reactions, and structural mechanics, as well as mass transport and fluid flow. By varying the wavelength, power, beam size, or pulse duration of the repair laser, researchers can control and fine-tune the optics-healing interaction, notes Laser Focus World. “Among the techniques being pursued by LLNL scientists,” the magazine says, “are infrared pulsed laser micromachining, laser chemical vapor deposition, and a three-dimensional printing additive process called selective laser melting. Exploring the effectiveness of these approaches requires extensive simulation in the form of multiphysics modeling of both the properties of the optical material and the laser’s attributes.” Matthews’ research team worked side-by-side with a development group led by Isaac Bass, John Adams, and Mike Nostrand, who ultimately produced working protocols suitable for a production environment.
The International Union of Pure and Applied Chemistry (IUPAC) has confirmed that Lawrence Livermore National Laboratory (LLNL) scientists and international collaborators have officially discovered elements 115, 117, and 118.
Lawrence Livermore teamed with the Joint Institute for Nuclear Research in Dubna, Russia (JINR) in 2004 to discover elements 113 and 115. LLNL worked again with JINR in 2006 to discover element 118. The LLNL/JINR team then jointly worked with researchers from the Research Institute for Advanced Reactors (Dimitrovgrad), Oak Ridge National Laboratory, Vanderbilt University and the University of Nevada, Las Vegas, to discover element 117 in 2010.
This discovery brings the total to six new elements reported by the Dubna-Livermore team (113, 114, 115, 116, 117, and 118, the heaviest element to date). The IUPAC announced that a Japanese collaboration officially discovered element 113. The LLNL/JINR team had submitted a paper on the discovery of elements 113 and 115 about the same time as the Japanese group.
In 2011, the IUPAC confirmed the name Livermorium for element 116. Livermorium (atomic symbol Lv) was chosen to honor Lawrence Livermore National Laboratory and the city of Livermore, Calif. A group of researchers from the Laboratory, along with scientists at the Flerov Laboratory of Nuclear Reactions at JINR, participated in the work carried out in Dubna on the synthesis of superheavy elements, including element 116. (Lawrencium — Element 103 — was already named for LLNL’s founder E.O. Lawrence).
An international team of researchers, including Livermore’s Roger Henderson, Dawn Shaughnessy, Ken Moody, and Mark Stoyer, has discovered five new atomic nuclei, isotopes of uranium, neptunium, americium, and berkelium: 216U, 219Np, 223Am, 229Am and 233Bk. 1To create the nuclei, the team bombarded a 300-nm-thick foil of curium (248Cm) with calcium (48Ca) nuclei at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. Occasionally, curium and calcium nuclei will collide, briefly form a compound nucleus (for about a sextillionth of a second), then fall apart into different nuclei. This process is called a deep inelastic transfer reaction and has the net effect of transferring some of the protons and neutrons from the 48Ca nucleus to the 248Cm nucleus. The new isotopes were found in the “debris” of such collisions and were identified by the characteristics of their alpha decay chains. The research team accomplished debris characterization with a new, fast, and highly sensitive separation and detection system that allowed efficient separation of “uninteresting” reaction debris from potential new nuclei. The results indicate that this synthesis method, together with the fast and sensitive separation and detection techniques applied in these experiments, promise the synthesis of new isotopes in the heaviest nuclei region of the periodic table.
Lawrence Livermore researchers are the recipients of three awards among the top 100 industrial inventions worldwide for 2014. The trade journal R&D Magazine announced the winners of its annual awards Friday, November 20, 2015, in Las Vegas, Nevada. With this year’s results, the Laboratory has now captured a total of 155 R&D awards since 1978.
This year’s winners are the Large-Area Projection Micro-Stereolithography (LAPμSL), a three-dimensional printing device; Zero-order Reaction Kinetics, a computing code; and the High-power Intelligent Laser Diode System (HILADS). Two of LLNL’s three R&D 100 awards—LAPμSL and HILADS—received internal “seed money” from the Laboratory Directed Research and Development Program. This funding enables the undertaking of high-risk, potentially high-payoff projects at the forefront of science and technology.
“I am extremely pleased that the Laboratory has received this recognition through the R&D 100 awards this year,” says Lab Director Bill Goldstein. “The Laboratory has again succeeded in receiving this noteworthy acclaim in a broad range of research areas that benefit the nation.”
A Lawrence Livermore National Laboratory (LLNL) team played a leading role in fielding the recent Source Physics Experiment (SPE-4 Prime) detonated at the Nevada National Security Site (NNSS).
The SPE tests, including the most recent one on May 21, consist of a series of seven underground, high-explosive field tests in hard rock that are designed to improve the United States’ ability to detect and identify low-yield nuclear explosions amid the clutter of conventional explosions and small earthquakes.
“As nuclear monitoring scientists, we are very excited by the new data from SPE-4 Prime,” said Bill Walter, the SPE scientific leader for LLNL and the SPE-5 chief scientist. “It is the most over-buried field explosion in granite from which we have ever obtained data, and the data return and quality look excellent.
“We will be able to compare this new data with the prior SPE shots, which were shallower, allowing us to directly measure and understand the role that the interactions of the Earth’s surface play in generating the signals we observe.”
The SPE-4 Prime experiment was detonated with a chemical explosive equivalent of 196 pounds of TNT in a contained environment 286 feet below ground.
A team of 27 LLNL engineers and technicians, led by physicist and SPE Campaign Manager Leon Berzins, was responsible for the design of the canister that contained the explosive charge, along with emplacing the canister downhole. LLNL also was responsible for the timing and firing of the shot.
The chemical explosives for the experiment were placed downhole in a one-and-a-half-week process that included a dry run of emplacing a canister without high explosives, Berzins said.
“It had been close to two years since we had our last SPE chemical explosion, so it was great to have this test to produce scientific data for our simulation and modeling work,” said Berzins, who worked on nine of the Laboratory’s 13 subcritical tests between the late 1990s and 2003.
“Livermore took on this challenge and was able to draw upon a wide spectrum of talent to be successful,” he said, noting that a number of Lab employees worked nights and weekends at LLNL and NNSS.
When Livermore and Los Alamos National Laboratory (LANL) conducted nuclear tests from the 1950s through 1992, the tests were conducted in a narrow range of depths and sizes for safety and cost factors.
“We’re trying to expand that range, so we can understand any potential future nuclear tests that would be outside the historic range,” Walter said. “The SPE tests are designed to improve our numerical modeling codes for monitoring nuclear explosions overseas.”
Information gathered from the experiment includes high-resolution accelerometer, infrasound, seismic, explosive performance, ground-based light detection and ranging (LIDAR), ground-based hyperspectral imagery and satellite data.
The sensor networks reported a successful data return that will advance current, state-of-the-art ground motion and seismic wave propagation models and algorithms toward a predictive capability.
“The seismic Source Physics Experiments substantially advance the United States’ efforts to develop, validate and improve on emerging technology,” said National Nuclear Security Administration (NNSA) Deputy Administrator for Defense Nuclear Nonproliferation Anne Harrington.
The SPE tests represent a U.S.-interagency-wide endeavor, with NNSA’s NNSS, LANL, LLNL, Sandia National Laboratories and the Department of Defense’s Defense Threat Reduction Agency all serving as partners in SPE-4 Prime, along with the University of Nevada-Reno.
NNSA’s three national laboratories have already used the data from the first three experiments in the series (SPE-1, executed in May 2011, SPE-2, executed in October 2011 and SPE-3 executed in July 2013).
NNSA has published a press release on the event.
The next shot in the SPE series, SPE-5, is slated to be staged during the fall at NNSS.
In November 2014, the Laboratory announced the signing of a contract with IBM to produce a next-generation supercomputer called Sierra. To be delivered in 2017, Sierra will serve the Advanced Simulation and Computing (ASC) Program as “a key tool for the three NNSA laboratories in pursuing predictive applications necessary to sustain the nation’s nuclear deterrent into the indefinite future without underground testing,” said Charlie Verdon, LLNL principal associate director for Weapons and Complex Integration. Specifically, Sierra will be dedicated to high-resolution weapons science and uncertainty quantification for weapons assessment.” Said LLNL Director Bill Goldstein, “This computer is a step toward keeping the U.S. at the forefront of science and technology.”
Sierra is part of the DOE-sponsored Collaboration of Oak Ridge, Argonne, and Lawrence Livermore (CORAL), which aims to delivery to each member laboratory a supercomputer boasting performance five times faster than today’s top systems. The laboratories will work with IBM, NVIDIA, and Mellanox to achieve speeds of approximately 150 petaflops. Sierra will begin laying the groundwork for exascale computing, with a heterogeneous accelerated-node architecture that represents one of the most promising paths to at least one exaflop (i.e., a quintillion floating-point operations) per second—one thousand times faster than today’s petaflop-scale (quadrillions of floating-point operations) systems.
The collaboration of Oak Ridge, Argonne, and Lawrence Livermore (CORAL) that will bring the Sierra supercomputer to the Lab in 2017 has been recognized by HPCWire with an Editor’s Choice Award for Best HPC Collaboration between Government and Industry. The award was received by Doug Wade, head of the Advanced Simulation and Computing (ASC) program, in the Department of Energy (DOE) booth at Supercomputing 2015 and representatives from Oak Ridge and Argonne. HPCWire is an online news service that covers the high-performance computing (HPC) industry. CORAL represents an innovative procurement strategy pioneered by Livermore that couples acquisition with research and development non-recurring engineering contracts that make it possible for vendors to assume greater risks in their proposals than they would otherwise for an HPC system that is several years out. Delivery of Sierra is expected in late 2017 with full deployment in 2018. This procurement strategy has since been widely adopted by DOE labs. CORAL’s industry partners include IBM, NVIDIA, and Mellanox. In addition to bringing Sierra to Livermore, CORAL will bring an HPC system called Summit to Oak Ridge National Laboratory and a system called Aurora to Argonne National Laboratory. Sierra, an IBM system, is expected to exceed 120 petaflops (120 quadrillion floating point operations per second) and will serve NNSA’s ASC program, an integral part of stockpile stewardship.
A new Department of Energy (DOE) initiative will allow industry to leverage the high-performance computing (HPC) capabilities of Lawrence Livermore, Oak Ridge, and Lawrence Berkeley national laboratories to advance clean energy manufacturing technologies. The new program was announced by David Danielson, assistant secretary for Energy Efficiency and Renewable Energy at DOE’s third annual American Energy and Manufacturing Competitiveness summit in Washington D.C. The High Performance Computing for Manufacturing Program (HPC4Mfg) will make $5 million available for qualified industry partners. HPC4Mfg will couple U.S. manufacturers with the national laboratories’ world-class computational research and development expertise to address key challenges in U.S. manufacturing. The program’s goal is to keep the U.S. at the forefront of innovation by accelerating advanced clean energy and energy-efficient technology.
“With HPC4Mfg, DOE is taking the lead in recognizing the untapped resources and potential economic impact that the national laboratories represent. HPC4Mfg is designed to lower the cost of entry and to ease the way for U.S. manufacturers to use high-performance modeling and simulation for a competitive edge,” says LLNL Director Bill Goldstein, who served as a panelist at the summit. Livermore will lead the HPC4Mfg program. The $5 million will initially fund eight to 10 projects to be selected through a review committee with representatives from DOE and the three national laboratories.
LLNL’s Sequoia supercomputer played a key role in an Earth mantle convection simulation by a University of Texas-led team that won the 2015 Gordon Bell Prize, announced at Supercomputing Conference 2015 (SC15). The team’s peak performance results were achieved on the full Sequoia system last summer, and the weak and strong scaling results figured prominently in the team’s presentation at the SC15 conference in Austin, Texas.
Livermore’s onsite IBM analyst Roy Musselman and Livermore Computing’s Scott Futral were acknowledged for their contributions to the project in carrying out the Sequoia calculations, as was the system access granted by DOE/NNSA. Entitled, “An Extreme-Scale Implicit Solver for Complex PDEs: Highly Heterogeneous Flow in Earth’s Mantle,” the winning submission was led by Johann Rudi from the University of Texas at Austin with a team including IBM, the Courant Institute of Mathematical Sciences, University of Texas at Austin, and the California Institute of Technology. “I’m gratified that Sequoia continues to contribute to groundbreaking calculations in computational science,” says Futral. Sequoia, a 20 petaflops (quadrillion floating point operations per second) IBM Blue Gene/Q system, remains the third high-performance computing (HPC) system on the Top500 list of the world’s most powerful computers.
The Gordon Bell Prize is awarded each year at SC to recognize outstanding achievement in HPC. The purpose of the award is to track the progress over time of parallel computing, with particular emphasis on rewarding innovation in applying HPC to applications in science, engineering, and large-scale data analytics.
Graphene is a 2-dimensional (2-D) material that offers a unique combination of low density, exceptional mechanical properties, large specific surface area, and excellent electrical conductivity. Recent progress has produced bulk 3-D assemblies of graphene, such as graphene aerogels, but they have a random microscopic architecture, which limits their performance compared with the potential of an engineered architecture. In a paper published in the April 22, 2015 online edition of Nature Communications1, a team of LLNL researchers2 report on the fabrication of graphene aerogel microlattices that have an engineered, periodic architecture. The team used a 3-D printing technique known as direct ink writing to make the material. The resulting material is lightweight, highly conductive, and exhibits “supercompressibility” – even after being compressed to 10% of its starting volume, the material returns to 95% of its original volume once the compressive stress is removed. Moreover, the printed aerogels are an order of magnitude stiffer than traditionally prepared bulk graphene materials that have comparable geometric density and specific surface areas3. Adapting and applying the 3-D printing technique to graphene aerogels opens the possibility for fabricating a myriad of complex aerogel architectures for applications ranging from energy storage, sensors, nanoelectronics, catalysis, and chemical separations.
1 C. Zhu, T. Y.-J. Han, E. B. Duoss, A. M. Golobic, J. D. Kuntz, C. M. Spadaccini, and M. A. Worsley, Highly compressible 3D periodic graphene aerogel microlattices. Nat. Commun. 6, Article number: 6962, Published online 22 April 2015. doi:10.1038/ncomms7962
2 The authors of the paper were Cheng Zhu, T. Yong-Jin Han, Eric Duoss, Alexandra Golobic, Joshua Kuntz, Christopher Spadaccini, and Marcus Worsley
3 This work was funded by the Lab’s LDRD Program.
Laboratory researchers are recapitulating the cardiovascular system’s intricate network of arteries, capillaries, and veins using an emerging technology: three-dimensional (3D) bioprinting. “It’s going to change the way we do biology,” says LLNL research engineer Monica Moya, the project’s principal investigator. “This technology can take biology from the traditional petri dish to establish a 3D physiologically relevant tissue patch with functional vasculature.” Using a 3D printer and a bioink made of materials compatible with the human body, Moya and her team have successfully printed structures with living cells and biomaterials. The material and environment are engineered to enable small blood vessels—human capillaries—to develop on their own.
Tubes are initially printed out of cells and other biomaterials to deliver essential nutrients to the surrounding printed environment. Eventually, the self-assembled capillaries are able to connect with the bioprinted tubes and deliver nutrients to the cells on their own, enabling these structures to function like they do in the body. Currently in the final year of a three-year project funded by Livermore’s Laboratory Directed Research and Development program (project 14-ERD-005, Biological Printing of Vasculature for Artificially Grown Tissue) Moya has used bioprinting to create an unorganized network of blood vessels, but she wants to engineer a directed hierarchy similar to those that exist in the body. Moya and other researchers will soon be able to utilize a brand-new 3D bioprinter capable of higher resolution and larger structures.
Historically, the way to alter the performance in reactive materials (i.e. thermites) has been to either change the formulation, or to change parameters, such as particle size, within a formulation. However, through 3D printing, a team of scientists and engineers at Lawrence Livermore National Laboratory and Harvard University have found that the architecture can play a strong role in exerting more control over the energy release rate of reactive composites. The team’s findings are published in the December 16th, 2015 issue of the journal Advanced Materials.
Through a 3D printing process called direct ink writing, researchers first constructed 3D conductive electrodes. Then, through another printing process called electrophoretic deposition (EPD), the team coated the surface of the conductive micro-architectures with a composite film of thermite nanoparticles. The researchers found that by creating the reactive material architectures, or RMAs, they could direct and manipulate the energy released by the material in ways never possible before.
“The big message here is we’re showing 3D printing can be used to change the dynamic behavior of materials,” Sullivan said. The findings could lead to new structural energetics, the discovery of previously unknown functions for reactive materials, and improve the safety and reliability of air bags.
This work was supported in part by Laboratory Directed Research and Development program (14-SI-004).
General Electric (GE) and Lawrence Livermore recently received $540,000 to develop open-source algorithms that will improve additive manufacturing of metal parts. The award is from America Makes National Additive Manufacturing Innovation institute that helps the United States advancement of three-dimensional (3D) printing. The project is intended to develop software algorithms that will allow selective laser melting (SLM) to produce even higher quality metal parts. SLM is a metal powder-based AM process in which a metal 3D part is produced using a high-energy laser beam to fuse metal powder particles together.
In order to print a 3D part using the SLM process, the user must enter data into the printer using a stereolithography file, which is a digitized 3D representation of the desired build. “With the SLM processes in place now, you don’t always end up with a part that is structurally sound,” says Ibo Matthews, a Livermore researcher for the Accelerated Certification of Additively Manufactured Metals Strategic Initiative and leads the Laboratory effort on the joint project. In an ideal system, the laser would be programmed to deliver laser scanning speeds and powers for different layers because the powder environment changes as the layer-by-layer buildup progresses.
Leveraging the capabilities of Lawrence Livermore’s high-performance computing and its expertise in lasers, Matthews and his GE colleagues are developing software algorithms that will be compatible with all 3D printers that produce metal parts and will enable more precise control of the laser parameters. Because the software will be made available to the public, Matthews hopes it will lead to more breakthroughs in the AM industry.
Researchers from Lawrence Livermore and a Bay Area company are exploring how design software can accelerate innovation for three-dimensional printing of advanced materials. Under an 18-month Cooperative Research and Development Agreement (CRADA), Livermore will use state-of-the-art software for generative design from San Rafael-based Autodesk Inc., as it studies how new material microstructures, arranged in complex configurations and printed with additive manufacturing techniques, will produce objects with novel physical properties.
In the project, Livermore researchers will leverage additive manufacturing, material modeling, and architected design (arranging materials at the micro- and nanoscale through computational design). Livermore and Autodesk have selected next-generation protective helmets as a test case for their technology collaboration, studying how to improve design performance. Helmets will likely benefit from additive manufacturing because their internal structures not only need to be lightweight, but also must absorb impact and dissipate energy predictably. It has yet to be determined what kinds of helmets will be designed under the CRADA, but sports helmets are possible, according to Livermore’s Eric Duoss.
The Defense Advanced Research Projects Agency (DARPA) recently selected Lawrence Livermore to join a collaborative research team that intends to build the world’s first neural system that will enable naturalistic feeling and movement in prosthetic hands. Known as Hand Proprioception and Touch Interfaces (HAPTIX), the program seeks to provide wounded service members with dexterous control over advanced prosthetic devices that substitute for amputated hands. If successful, HAPTIX also intends to reduce “phantom limb” pain, a sensation some amputees can feel despite the removal of a limb.
Lawrence Livermore’s Neural Tech Group and collaborators (Case Western Reserve University and the Louis Stokes Cleveland Veterans Administration Medical Center) will work to develop neural interface systems that measure and decode motor signals recorded in peripheral nerves and muscles in the forearm by using tiny electrodes. “The HAPTIX project intends to achieve a phenomenal breakthrough in prosthetics never thought possible,” says Livermore’s project leader and engineer Sat Pannu.
For these neural interface systems, Livermore resolves to further develop the advanced prosthetic limb systems established under DARPA’s Revolutionizing Prosthetics and Reliable Neural-Interface Technology programs. Pannu and his team of engineers are developing wireless electronic packages for HAPTIX called smart packages; these packages would contain electronics that record and stimulate the peripheral nervous system to control movement and sensation in a patient’s prosthetic hand. This project was supported by Livermore’s Laboratory Directed Research and Development program, under project 12-LW-008, Comprehensive Study and Treatment of Major Depressive Disorder Using Electrical and Chemical Methods.
Lawrence Livermore scientists, as part of an international team, have discovered the most Jupiter-like planet ever seen in a young star system. Using a new advanced adaptive optics device on the Gemini Planet Imager (GPI) on the Gemini South Telescope in Chile, the team took an image of the planet. Called 51 Eridani b, the planet could help scientists discover how Jupiter and other gas giants form and shape their planetary systems. Since a planet’s luminosity is a function of age and mass and initial conditions, it can provide insights into its formation, according to Bruce Macintosh of Stanford University, Lawrence Livermore, and lead author on a paper1 appearing in the Aug. 14 edition of the journal, Science.
The GPI was designed specifically for discovering and analyzing faint, young planets orbiting bright stars. After GPI was installed, the team set out to look for planets orbiting young stars. According to the cosmic clock, 51 Eridani is a young star—only 20 million years old—and this is exactly what made the direct detection of the planet possible. Astronomers observed the planet’s characteristics, which seem to suggest that it is similar to what Jupiter was like in its infancy. Livermore’s scientific involvement and technical support of the GPI is led by Stephen Ammons and funded by the Laboratory Directed Research and Development program under project 14-ERD-076.
1 B. Macintosh, et al., "Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini Planet Imager" Science (2015) doi: 10.1126/science.aac5891.
Discover Magazine ranked a paper1 by Rick Kraus, entitled, “Impact Vaporization of Planetesimal Cores in the Late Stages of Planet Formation,” as number 62 out of the top 100 scientific stories of 2015 (across all fields of science). Kraus’ paper was published online in the March 2015 issue of Nature Geoscience. The Discover Magazine ranking has already been published online.
The paper was the result of a collaboration between Lawrence Livermore and Sandia national laboratories, Harvard, and the University of California at Davis. The team developed an experimental technique to measure the entropy increase during shock compression. By measuring the entropy, they found that significantly more iron was shock vaporized during planet formation than previously thought. The Nature Geoscience article describes how our improved understanding of iron at extreme conditions helps answer important questions about the timing of Earth’s core formation, as well as helps to solve a mystery about the formation of the Moon.
1 R. G. Kraus, S. Root, R. W. Lemke, S. T. Stewart, S. B. Jacobsen, and T. R. Mattsson, “Impact Vaporization of Planetesimal Cores in the Late Stages of Planet Formation,” Nature Geoscience (2015) doi:10.1038/ngeo2369.
Lawrence Livermore scientists, along with university colleagues, developed a new type of carbon capture media composed of core-shell microcapsules. These microcapsules consist of a highly permeable polymer shell and a fluid (made up of sodium carbonate solution) that reacts with and absorbs carbon dioxide (CO2). The capsules keep the liquid contained inside the core, and allow the CO2 gas to pass back and forth through the capsule shell. The team’s work was published online1 in the February 5, 2015, edition of Nature Communications.
The aim of carbon capture is to prevent the release of large quantities of CO2—a greenhouse gas that traps heat and makes the planet warmer—into the atmosphere from fossil fuel use in power generation and other industries. "Our method is a huge improvement in terms of environmental impacts because we are able to use simple baking soda, present in every kitchen, as the active chemical," says Roger Aines, one of the Lawrence Livermore team members. Unlike more caustic sorbents used in capturing CO2, the microcapsules only react with the gas of interest (in this case CO2).
Today’s carbon capture methods can be harmful to the environment. The team’s research will enable CO2 producers to switch from caustic fluids, such as monoethanol amine to capture CO2, to more benign ones, like carbonates, is a key attribute of the team’s research. The new process can be designed to work with coal or natural gas-fired power plants, as well as in industrial processes like steel and cement production.
1 Encapsulated liquid sorbents for carbon dioxide capture, J. J. Vericella, S. E. Baker, J. K. Stolaroff, E. B. Duoss, J. O. H. IV, J. Lewicki, E. Glogowski, W. C. Floyd, C. A. Valdez, W. L. Smith, J. H. Satcher Jr., W. L. Bourcier, C. M. Spadaccini, J. A. Lewis, and R. D. Aines. Nature Communications. 6, 6124 (2015) doi:10.1038/ncomms7124
A group of national particle physicists—known as the Lattice Strong Dynamics Collaboration and led by a Lawrence Livermore team—has combined theoretical and computational physics techniques to model dark matter by using the Laboratory’s massively parallel 2-petaflop Vulcan supercomputer. It identifies dark matter as naturally “stealthy” today, but would have been easy to see via interactions with ordinary matter in the extremely high-temperature plasma conditions that pervaded the early universe. A paper1 on this work, called, “Direct Detection of Stealth Dark Matter Through Electromagnetic Polarizability,” appears in an upcoming edition of the journal Physical Review Letters and is an “Editor’s Choice.”
Though essentially invisible, dark matter’s interactions with gravity produce striking effects on the movement of galaxies and galactic clusters, leaving little doubt of its existence. The key to stealth dark matter’s split personality is its compositeness and the miracle of confinement. At high temperatures these electrically charged constituents interact with nearly everything, but at lower temperatures they bind together to form an electrically neutral composite particle.
Similar to protons, stealth dark matter is stable and does not decay over cosmic times. However, it produces a large number of other nuclear particles that decay shortly after their creation. These particles can have net electric charge but would have decayed away a long time ago. In a particle collider with sufficiently high energy, these particles could be produced again for the first time since the early universe.
1 T. Appelquist, E. Berkowitz, R. C. Brower, M. I. Buchoff, G. T. Fleming, X.-Y. Jin, J. Kiskis, G. D. Kribs, E. T. Neil, J. C. Osborn, C. Rebbi, E. Rinaldi, D. Schaich, C. Schroeder, S. Syritsyn, P. Vranas, E. Weinberg, and O. Witzel, “Direct Detection of Stealth Dark Matter Through Electromagnetic Polarizability,” Phys. Rev. Letters (2015)
Lawrence Livermore National Laboratory atomic physicist Kennedy Reed has been elected president-designate of the International Union of Pure and Applied Physics (IUPAP).
Reed is the first American elected to head this global physics organization since Nobel Laureate Burton Richter, who was president of IUPAP from 1999 to 2002.
Reed will serve a three-year term as president-designate, followed by a three-year term as the president of IUPAP, culminating with a three-year term as the organization’s past president. IUPAP assists in the worldwide development of physics, fosters international cooperation in physics, and helps in the application of physics toward solving problems of concern to humanity.