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Los Alamos National Laboratory

Los Alamos National Laboratory

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STE Highlights, August 2019

Awards and Recognition

Dubey, Janecky, and Swift honored as AAAS Fellows

Manvendra  Dubey

Manvendra Dubey

David Janecky

David Janecky

Greg Swift

Greg Swift

Los Alamos scientists Manvendra Dubey, David Janeky, and Greg Swift were honored as Fellows at the 2019 American Association for the Advancement of Science (AAAS) annual meeting in Washington, D.C.

The honorees were presented with a certificate and AAAS gold and blue rosette pin to signify science and engineering, respectively. AAAS began recognizing fellows in 1874 and touts scientists such as Thomas Edison and Linus Pauling as members of the select group.

The selection process is quite rigorous: a minimum of a four-year membership in AAAS, submission of a list of publications and curriculum vitae, and nomination by three previously elected fellows who are current AAAS members. The names of all 416 AAAS fellows were published in the News and Notes section of the November issue of Science.

Manvendra Krishna Dubey (Earth System Observations, EES-14)

Dubey was selected under the Atmospheric and Hydrospheric Sciences section of AAAS. He has over 120 publications with approximately 5,100 citations, as well as two patents. His seminal work informs climate–biogeochemistry–carbon models to improve predictions of climate change and air quality for a responsible energy policy. In 2017, Dubey was honored as a Los Alamos National Laboratory Fellow.

David Janecky (Assembly Operations, PT-3)

Janecky was selected under the geology and geography section of AAAS. He was elected for pioneering contributions to the field of fluid-rock interactions at high temperatures in deep ocean rift valleys and vents, and for distinguished service to scientific organizations. Janecky has worked at Los Alamos National Laboratory for nearly 34 years in a breadth of disciplines.

Greg Swift (Condensed Matter & Magnet Science, MPA-CMMS)

Swift was selected under the physics section of AAAS. He was elected for pioneering developments in the science and technology of thermoacoustics (the interaction between temperature, density, and pressure variations of acoustic waves), for his influential textbook Thermoacoustics, and for efforts on behalf of science education in New Mexico.

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Frigo and Monroe win Women in Technology awards

Janette Frigo

Janette Frigo

Laura Monroe

Laura Monroe

The New Mexico Technology Council honored LANL’s Janette Frigo (Space Data Science and Systems, ISR-3) and Laura Monroe (High Performance Computing Design, HPC-DES) with Women in Technology awards at the 11th Annual Women in Technology Celebration Awards Gala held in Albuquerque, New Mexico. They were recognized for their exceptional work in STEM, commitment to community, and mentorship of women.

“Janette and Laura exemplify qualities that our Laboratory holds in the highest esteem: outstanding work in their fields and giving back to the community,” said Thom Mason, director of Los Alamos National Laboratory.

Janette Frigo joined the Laboratory as an engineer in 1997. She is best known for inventing an award-winning long-range wireless sensor network. This technology allows multiple sensors to talk to each other over vast distances and in harsh environmental conditions, and it has broad applications in environmental management, ranching, security, and more. Frigo is also a longstanding leader and contributor to the women-led Expanding Your Horizon’s conference that exposes middle and high school girls to STEM fields through hands-on workshops and science and career fairs.

Laura Monroe joined the Laboratory as a mathematician/computer scientist in 2000. She is best known for originating and leading the Laboratory’s inexact computer project, meant to uniquely address challenges related to Moore’s Law (pushing the limits of atomic scale). Monroe is also committed to recruiting and retaining women in the computer science field at the Lab. More than half of her interns and 30 percent of her computing project team are female.

Technical contacts: Janette Frigo and Laura Monroe

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33 awardees recognized at the 2019 Student Symposium

Student Symposium

Teagan Nakamoto of Detonation Science and Technology is one of 185 presenters at the 2019 Student Symposium.

The Los Alamos National Laboratory holds an annual Student Symposium to showcase interns and the projects students conduct Lab-wide. Students also win awards for their posters in various categories.

This year, the symposium took place August 6–7 in the Laboratory’s Research Library. A total of 185 individuals and teams presented in 11 categories: biosciences, chemistry, computing, earth and space sciences, engineering, health and safety, information technology, materials science, mathematics, other (non-technical), and physics.

More than 100 LANL staff volunteers (funded by LANL’s service time for STEM education) judged the students on poster visualization and content, presentation effectiveness, and overall clarity. On Aug. 8, a recognition ceremony awarded 33 of the presenters for their outstanding contributions. Student winners are listed below.

2019 Winners by Category

Biosciences

  • Beauty Kolade: Validating experimental results of digitoxin using molecular dynamics
  • Elizabeth Wait: Functional dynamics in a cancer protein
  • Michaela Baysinger: Probiotics of algae biofuels

Chemistry

  • Selena Staun: Assessing covalency in transuranic nitrides
  • Kevin Glennon: A forensic investigation of legacy separated Pu at Los Alamos National Laboratory

Computing

  • Hayden Jones: Robust detection of computer-generated text
  • Callum Farrell: Verification methods for tabular equations of state in xRAGE

Earth & Space Sciences

  • Greta Miller: Climate impacts on infiltration in Northern New Mexico
  • Daniel Castano: Comparing emission profiles of wildfires vs. controlled fires in the Chaparral and Eglin landscapes

Engineering

  • Vedant Mehta: Powering the Red Planet in pursuit of becoming interplanetary species
  • Jianchao Zhao: Silicate sequestration for water treatment
  • Kelly Verner: Production of molybdenum-99 via fissile solution reactor and electron beam accelerator
  • Peter Fickenwirth: In situ ultrasonic quality inspection for metallic additive manufacturing
  • Sheera Lum: Characterizing PBX 9502 ratchet growth due to thermal effects
  • Thomas Roberts: Dynamic effects of preload in hyperelastic foam models
  • Kayla Gill: Recirculating water system for metallography
  • Jihyun Yang, Renan Rojas-Gomez: Data-driven FWI methods for seismic imaging: Generalization and robustness study

Health & Safety

  • Rebecca Wantuck: Glovebox worker dexterity in overgloves

IT

  • David Butts: Using TRANSIMS for evacuation planning

Materials Science

  • Sina Lewis: Surface core level shifts of lead halide perovskites
  • Natalia Rubio: Corrosion of refractory metals in high-temperature LBE
  • Cameron Richards: Optical properties of BaFCl:Eu2+ scintillating composites for medical X-ray imaging
  • Andre Gouws: Selective laser flash sintering of aluminum nitride

Mathematics

  • Philippa Chadwick, Oscar Goodloe, Nilesh Mukundan: Quantitative predictors of political instability in Pakistan  

Other (non-technical)

  • Asif Ali, Thomas Chadwick, Andrew Port: Building a digital historical narrative using open-source tools

Physics

  • Christopher Roper: What are the limits to jxB acceleration of quasineutral plasmas?
  • Landon Tafoya: A dense plasma focus as a potential source for neutron radiography
  • Rachel Sidebottom: Au-leaf phantoms of Au-tagged tumors to assess proton radiography for image-guided proton therapy

Technical contact: Cassandra Casperson

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Kolman honored as NACE fellow

David Kolman

David Kolman

David Kolman of the Los Alamos National Lab’s Detonator Production Division (DET-DO) was honored as a 2019 fellow of the National Association of Corrosion Engineers (NACE). One of the 10 selected from around the world, Kolman was cited for his outstanding achievements in recognizing and mitigating failures of radioactive materials and radioactive container materials.

Specifically, Kolman’s development of a test program to assess the limits for safe storage along with the establishment of guidelines for the long-term storage of materials were singled out for this honor. Kolman’s work has aided the United States in safely treating, packaging, and storing at-risk strategic materials.

NACE was established in 1943 as the worldwide corrosion authority. Today, NACE boasts 36,000 members in over 130 countries. Kolman exemplifies NACE’s mission to help protect people, assets, and the environment from the adverse effects of corrosion.

Technical contact: David Kolman

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Bioscience

Boosting biofuels and reducing plant waste—algae that does it all

Amanda Barry of Los Alamos’ Bioenergy and Biome Sciences group samples algae cultures grown in the LANL environmental photobioreactor (ePBR) matrix.

Amanda Barry of Los Alamos’ Bioenergy and Biome Sciences group samples algae cultures grown in the LANL environmental photobioreactor (ePBR) matrix.

Algae holds the potential to be an invaluable biofuel, and researchers at Los Alamos have boosted that potential even further. Through their study of a freshwater production strain of microalgae, Auxenochlorella protothecoides, they found that algae can “eat” leftover plant material, such as the part of the corn plant left in a field after harvest or the grass clippings from your backyard. Not only does this reduce plant waste, it also increases cultivation productivity and improves the economic viability of algal-derived biofuels.

This research was recently selected to appear in the 2019 American Institute of Aeronautics and Astronautics (AIAA) Year in Review Journal, representing LANL’s top contribution to alternative fuels. Algae possess the ability to produce refinery-compatible diesel and jet fuel precursors, making this study particularly relevant for AIAA.

Going beyond the initial discovery, these researchers also performed genomic, proteomic, and transcriptomic analyses to discover how this strain of algae is able to use plant waste as a food source; algae are typically grown photosynthetically in open ponds where the feeding of pure sugars can lead to contamination with other organisms. Delving into the molecular mechanisms behind the utilization of alternate carbon sources can lead to new strategies for algae product and biofuel production.

This research supports the Lab’s Energy Security mission area and Materials of the Future science pillar. This work was partly supported by a grant from the Laboratory Directed Research and Development Early Career Research Program at Los Alamos National Laboratory and funds provided by the U.S. Department of Energy’s Bioenergy Technologies Office.

Reference: Brian W. Vogler (Colorado School of Mines; LANL Bioscience), Shawn R. Starkenburg (LANL Bioscience), Nilusha Sudasinghe (LANL Bioscience Division), Jenna Y. Schambach (LANL Bioscience Division), Joseph A. Rollin (National Renewable Energy Lab), Sivakumar Pattathil (Complex Carbohydrate Research Center), Amanda N. Barry (LANL Bioscience Division). “Characterization of plant carbon substrate utilization by Auxenochlorella protothecoides.” Algal Research, 2018; 34: 37 DOI: 10.1016/j.algal.2018.07.001

Technical contact: Amanda Barry

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Capability Enhancement

Drilling underway in Nevada for the Advanced Sources and Detectors Scorpius project

Mining in the U1a 104 drift in Nevada commenced on June 19, 2019—a significant milestone for the ECSE project.

Mining in the U1a 104 drift in Nevada commenced on June 19, 2019—a significant milestone for the ECSE project.

In 2014, the need for new capabilities for plutonium research was identified and approved by the National Nuclear Security Administration. Los Alamos National Laboratory, Sandia National Laboratories, Lawrence Livermore National Laboratory, and Nevada National Security Site are working together under the umbrella term the Enhanced Capabilities for Subcritical Experiments (ECSE) to lay the groundwork for these new capabilities. The portfolio consists of four major elements:

  • The U1a Complex Enhancements Project (UCEP)—a separate line item to prepare the underground for Neutron Diagnosed Subcritical Experiments (NDSE) and multi-pulse radiography (new accelerator).
  • Research to develop neutron sources and detectors for NDSE.
  • An entombment drift for disposition of spent subcritical experiments (SCE).
  • The Advanced Sources and Detectors (ASD) Project (nicknamed Scorpius), which is the development of the multi-pulse radiographic machine as a Capital Major Item of Equipment.

In February of 2019, the Alternative Election, or Critical Decision 1 (CD-1), was approved for Scorpius, authorizing the development of a preliminary design that will lead to baselining the project in 2021. In addition, UCEP received CD-2/3 (baseline/construction) for a portion of the project in March 2019.

These approvals led to the project’s most recent milestone. In June 2019, drilling in Nevada at the U1a Complex commenced. As of July 3, 16 feet of U1a’s 104 drift were mined, which is approximately 8 percent of the total planned mining of that drift.

Scorpius will be a 20-megaelectronvolt linear induction accelerator diagnostic tool. Using multi-pulse flash x-rays, Scorpius will radiograph the late stages of implosion with test devices, without actually going critical. This is a unique capability that will use real plutonium (provided by Los Alamos’ PF-4) in subcritical experiments housed safely underground in the U1a Complex. Scorpius will enable modern certification and assessment of the current and future nuclear stockpile.

ECSE is a highly collaborative project that will deliver cutting-edge capabilities. The first experiment using Scorpius is anticipated in 2025, and the partners are on track for that date. The ASD partners also completed an Annual Project Review in early June 2019. It took place at the Nevada Field Office in North Las Vegas and was considered a success in terms of collaboration, technical progress, and planning.

This capability supports the Laboratory’s Nuclear Deterrence mission area and the Nuclear and Particle Futures science pillar. Funding for this project is through the National Nuclear Security Administration.

Reference: Here are related articles on this topic:

Technical contact: Dave Funk

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Chemistry

Using transition metal catalysis to generate high-pressure gas

This research was featured on the cover of Chemistry, A European Journal, and describes the chemistry of gas generation via a manganese-based catalyst. The researchers reported a first‐row transition metal catalyst that rapidly releases high-pressure gas (rather than water), similar to a fire hose. (Cover art: Josh Smith, LANL)

This research was featured on the cover of Chemistry, A European Journal, and describes the chemistry of gas generation via a manganese-based catalyst. The researchers reported a first‐row transition metal catalyst that rapidly releases high-pressure gas (rather than water), similar to a fire hose. (Cover art: Josh Smith, LANL)

Gas pressure can be employed to perform mechanical work by inducing a volume change. Some examples of work performed with gas pressure include firing actuators, pushing pistons, and spinning turbines. In many cases, the pressurized gas necessary to perform the work is stored in high-pressure steel cylinders and released with the help of a regulator as the work is needed. Harnessing work through this method is reliable and well established, although not without its drawbacks. For applications where weight savings is crucial, gas cylinders increase the mass of the system both inherently as well as through required engineering for conceivable over-pressurization from the cylinder.

One approach to solving this long-standing problem is to generate the needed gas directly from a liquid, and for the past five years, Nickolas Anderson, James Boncella, and Aaron Tondreau of Los Alamos’ C-IIAC have been working on weight-savings methods of generating gas pressure through the chemistry of transition metal catalysis.

Formic acid (FA) has long been studied as a potential hydrogen-storage medium. The hydrogenation of CO2 to form FA and the reverse dehydrogenation reaction provide scientists the opportunity to study the reaction from both sides. For the purpose of pressure generation, the dehydrogenation of FA produces two equivalents of gas for a given quantity of FA; when a given volume of formic acid is converted into its gaseous components, H2 and CO2, a volume change of roughly 1400-fold occurs, providing an opportunity to turn a chemical reaction into mechanical work. This conversion happens via a metal catalyst.

Reaction scheme showing the dehydrogenation of formic acid (FA) using the new manganese-based catalyst. Several pressurization/venting cycles generated with sequential additions of FA are shown. An amine base is used as a co-catalyst in the reaction, and the results with triethylamine and tributylamine are shown. Resultant pressure can be tuned by changing the amounts of FA in the catalysis; the blue curve shows the pressure generated in a reaction using 1 mL of FA, and the red curve shows the pressure generated in a reaction using 0.5 mL of FA under otherwise identical conditions.

Reaction scheme showing the dehydrogenation of formic acid (FA) using the new manganese-based catalyst. Several pressurization/venting cycles generated with sequential additions of FA are shown. An amine base is used as a co-catalyst in the reaction, and the results with triethylamine and tributylamine are shown. Resultant pressure can be tuned by changing the amounts of FA in the catalysis; the blue curve shows the pressure generated in a reaction using 1 mL of FA, and the red curve shows the pressure generated in a reaction using 0.5 mL of FA under otherwise identical conditions.

However, significant drawbacks have hindered the practical development of this high-pressure gas generation, which include sensitivity of the metal catalyst to high FA concentration, slow turnover, and the formation of water and CO in a competitive dehydration reaction. To mitigate these issues, the LANL scientists employed a novel, earth-abundant manganese catalyst alongside an amine co-catalyst in the reaction. With this approach, FA was converted into high-pressure gas at rates that rival or exceed traditional precious metal catalysts. The work was recently published in Chemistry: A European Journal (doi: 10.1002/chem.201703722) and featured on the journal’s cover. The newly developed manganese catalyst exhibits rapid rates of FA dehydrogenation and can generate high gas pressures within minutes. Additionally, the catalyst can be reused for subsequent catalytic cycles, an improvement over a previously reported ruthenium catalyst studied by the same researchers.

The potential weight savings and increased efficiency over the use of steel cylinders was the motivation to begin developing these systems. Transitioning from precious metals to earth-abundant first-row transition metals produces an ancillary benefit to the chemistry, allowing scientists to employ robust catalysis while circumventing the economic and environmental concerns that arise when using traditional noble metal-based catalyst systems. Additional work is ongoing on gas-generating catalyst systems as the LANL scientists continue to explore applications and advances in this technology.

This research supports the Laboratory’s Energy Security mission area and the Materials of the Future science pillar. Director’s Post Doctoral Fellowships provided funding for Tondreau (Fellowship #20150743PRD3) and Anderson (Fellowship #20170685PRD3). Additional partial funding was provided by the U.S. Department of Energy Science Campaign 5.

Reference: Nickolas H. Anderson (PT-1), James Boncella (C-IIAC), Aaron M. Tondreau (C-IIAC). “Manganese‐Mediated Formic Acid Dehydrogenation,” Chemistry, A European Journal. 05 July 2019, https://doi.org/10.1002/chem.201902329

Technical contact: Aaron M. Tondreau

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Earth and Environmental Sciences

Improving prediction of radioactive gas seepage for nuclear testing treaty verification

Schematic of gas transport through a rock fracture subjected to variation in barometric pressure. Zoom-ins illustrate the processes of volatilization (gas moving from water to air), diffusion (moving from fracture to matrix), and dissolution (moving from air to water) into the matrix.

Schematic of gas transport through a rock fracture subjected to variation in barometric pressure. Zoom-ins illustrate the processes of volatilization (gas moving from water to air), diffusion (moving from fracture to matrix), and dissolution (moving from air to water) into the matrix.

The length of time it takes for radioactive gases to seep from an underground nuclear test to the ground surface is crucial for verification of nuclear testing treaties, such as the Comprehensive Nuclear Test Ban Treaty. The identification of short-lived radioactive gases emanating from the ground surface at a suspected nuclear test location could provide “smoking gun”-type evidence of a nuclear test. Accurate predictions of radioactive gas arrival time and detection window (duration of time gas concentration is above its detection threshold) are critical for procuring this type of evidence. Los Alamos researchers are working toward improving such predictions.

Accurately predicting the radioactive gas arrival time and detection window is complicated by many factors, including rock properties at the site; existence of natural fractures, faults, and blast-induced fractures; barometric variations (changes in atmospheric pressure produce oscillatory flow into and out of fractured rock); depth of burial; nuclear device yield; topography; degree of saturation of the rock; etc. These factors influence the processes of radioactive gas diffusion, dissolution, and volatilization (see figure) which control the rate of gas seepage toward the ground surface during barometric pressure oscillations.

In a recent publication, scientists in the Earth and Environmental Sciences (EES) division revealed the importance of gas solubility in accurately predicting gas seepage. Gases flowing through the subsurface dissolve in the water that occupies void spaces in rock (pore water) up to their solubility limit, or point at which gas concentrations in the air and water are in equilibrium. When gas concentrations are out of equilibrium, the dual processes of dissolution (gas dissolving from air into water) and volatilization (gas escaping water into air) bring the concentrations back into equilibrium. The rate at which this dissolution occurs is variable depending on the gas’ free-air and water diffusion coefficients, interfacial area between the air and water present in the void spaces of the subsurface, width of the boundary layer across which dissolution occurs, salinity, temperature, etc. Previous conjecture implied that gases in the aqueous phase (dissolved in the pore water) resulted in retardation of gas transport, but this study revealed that is not always the case.

Time series of relative gas concentrations in a rock fracture subjected to barometric pumping at the ground surface under cases of greatest gas transport enhancement (top) and delay (bottom) due to the presence of pore water. The gas diffusion coefficient (D*) and dissolution coefficient (Dd) are noted. The blue lines are concentrations with pore water, whereas the green lines are concentrations for associated simulations without pore water. The degree of gas saturation (S) is indicated at the end of each line (saturation is zero for simulations without pore water). The gray shaded region indicates the amount of enhancement or delay due to the presence of pore water.

Time series of relative gas concentrations in a rock fracture subjected to barometric pumping at the ground surface under cases of greatest gas transport enhancement (top) and delay (bottom) due to the presence of pore water. The gas diffusion coefficient (D*) and dissolution coefficient (Dd) are noted. The blue lines are concentrations with pore water, whereas the green lines are concentrations for associated simulations without pore water. The degree of gas saturation (S) is indicated at the end of each line (saturation is zero for simulations without pore water). The gray shaded region indicates the amount of enhancement or delay due to the presence of pore water.

The scientists discovered through numerical investigations that the rate of dissolution—specific to a given gas—can have a large impact on the arrival time and detection window of radioactive gases at the ground surface. They compared rates of gas transport to the ground surface under simulations both with and without pore water for various dissolution rates, gas diffusion rates, and degrees of saturation. Their findings indicate that gases with dissolution coefficients less than 10-11 m2/s have enhanced rates of transport whereas gases with dissolution coefficients greater than 10-11 m2/s have retarded rates of transport when pore water is present compared to when pore water is absent (Figure 2). This enhanced or delayed transport is maximized at higher degrees of gas saturation within the rock. These results suggest that predictions of radioactive gas arrival time and detection window at suspected nuclear test locations should incorporate the role of rate-limited pore water storage in enhancing or retarding gas transport.

This research supports the Laboratory’s Global Security mission and the Information Science and Technology and Science of Signatures science pillars. Funding for this work was provided by National Nuclear Security Administration Office of Defense Nuclear Nonproliferation Research and Development and the Defense Threat Reduction Agency, the Los Alamos National Laboratory Institutional Computing Program, and the U.S. Department of Energy.

Reference: Dylan Harp (Computational Earth Science, EES-16), John Ortiz (EES-16), Sachin Pandey (EES-16), Satish Karra (EES-16), Dale Anderson (Geophysics, EES-17), Chris Bradley (EES-17), Hari Viswanathan (EES-16), and Phil Stauffer (EES-16). “Immobile pore-water storage enhancement and retardation of gas transport in fractured rock.” 2018. Transport in Porous Media, https://doi.org/10.1007/s11242-018-1072-8.

Technical contact: Dylan Harp

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Educational Outreach

Cyber Fire School teaches students cybersecurity and data manipulation

Registration is now open for the fall Foundry 15 Cyber Fire event in San Diego, Calif.

Registration is now open for the fall Foundry 15 Cyber Fire event in San Diego, Calif.

Cyber Fire was created in 2005 by LANL’s Neale Pickett (Advanced Research in Cyber Systems, A-4) as a means to teach cybersecurity techniques and fill in holes in the traditional pedagogy. Since that time, Cyber Fire has evolved into an umbrella of programs including a summer school, a foundry for incident investigation training, and a simulation for practice with real incident data. These programs are specialized for different audiences: the summer school is aimed at undergraduate and graduate students, the foundry is aimed at government and critical infrastructure employees, and the simulation is aimed at national laboratory employees. The training events are staggered throughout the year and in various locations. The most recent event was the 2019 summer Cyber Fire School held at LANL.

Nicknamed the Cyber Fire Toaster, the 2019 Cyber Fire School took place between June 4 and Au. 9. This 10-week program is part of LANL’s Information Science and Technology Institute (ISTI), which is aimed at recruiting and educating select undergraduate and graduate students. In total, four undergraduate students and six graduate students participated in the Cyber Fire School.

Grace Herrera (A-4) is the deputy director of Cyber Fire and had the opportunity to help select the candidates for the 2019 school. As a previous participant, Herrera is a strong advocate for the program’s value: “The Cyber Fire Toaster is a great opportunity for networking and building hands-on skills.”

Herrera and Pickett are not the only cyber experts available to the students. “We bring in experts from other national laboratories to teach as well,” Herrera says. The students are cognizant of the benefits of the program. “Most people would kill for this opportunity,” said one 2019 student. “We learned skills here that are not traditionally taught in computer science programs, and we have access to the practitioners if we have questions,” said another student.
Cyber Fire founder Neale Pickett, left, mentors a Cyber Fire School student. The Cyber Fire School is a strong Department of Energy recruitment tool.

Cyber Fire founder Neale Pickett, left, mentors a Cyber Fire School student. The Cyber Fire School is a strong Department of Energy recruitment tool.

The Cyber Fire School is a combination of what is offered in the foundry and simulation events. These students use real data to gain incident response skills. They learn the cyber sleuthing techniques to investigate cyber security incidents, and they learn how to approach each incident creatively. Instead of a classroom-instructor methodology, the experts take on a mentor role for the students. Cyber Fire is a learn-by-doing environment.

Registration is now open for the fall Foundry 15 Cyber Fire event to be held Nov. 18–22 in San Diego, Calif.

Cyber Fire supports the Laboratory’s Global Security mission area and the Information Science and Technology science pillar. This program is funded by the U.S. Department of Energy. Cyber Fire partners include Lawrence Livermore, Idaho, Sandia, Oak Ridge, Argonne, and Pacific Northwest national laboratories.

Technical contact: Grace Herrera

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Explosive Science and Shock Physics

New high-performing, low-sensitivity explosive compounds

The synthesis scheme of Compound 7, which is the most notable of the new polycyclic N-oxide compounds.

The synthesis scheme of Compound 7, which is the most notable of the new polycyclic N-oxide compounds.

Safe explosive may sound like an oxymoron, but it’s a balance Los Alamos researchers are trying to strike in their work. Not only are explosives important to our nation’s security, they are ubiquitously used in fracking, mining, construction, and other industries. Improving the safety of an explosive while maintaining its performance is a challenging task, however, the impact of such a breakthrough would be experienced worldwide—safeguarding the lives of many.

Recently, Los Alamos researchers in Explosive Science and Shock Physics (M-DO) along with collaborators from the Naval Research Laboratory developed new high-performing, low-sensitivity explosive compounds, specifically polycyclic N-oxide compounds. The new compounds are energetic, with excellent explosive properties, while they maintain low mechanical sensitivities: very low sensitivity toward impact and insensitivity toward friction. One compound of the group, Compound 7, stands out beyond the rest because it is thermally stable, insensitive, and superior in detonation properties to TATB (a highly praised insensitive explosive).

The researchers targeted polycyclics (which are traditionally used in molecular semiconductors, light emitting diodes, and field-effect transistors) to generate new explosive materials because of their advantageous crystal packing and high crystal densities. If harnessed properly, these attributes can be used to design a highly energetic yet insensitive explosive. The researchers were successful in synthesizing such compounds and were able to do so under mild reaction conditions.

Thus far, the promising explosive performance properties of this material have only been determined through theoretical calculations. In order to obtain experimental performance properties, such as detonation velocity and detonation pressure, more material will be required. The scale up and experimental explosive testing of these materials is now being investigated to provide the quantity necessary for the next phase of characterization.

Crystal structure of the very promising Compound 7.

Crystal structure of the very promising Compound 7.

One of these same Los Alamos researchers, David E. Chavez, had success in developing another high-performing, low-sensitivity explosive, called bis(1,2,4-oxadiazole)bis(methylene) dinitrate and nicknamed BOM, with collaborators at the Army Research Laboratory. (View a video on the BOM explosive here.)

This research supports the Laboratory’s Nuclear Deterrence mission area and the Materials of the Future science pillar. Funding was provided by the Office of Naval Research (Award No. N00014-11-AF-0-0002).

Reference: Christopher J. Snyder (M-7), Lucille A. Wells (M-7 student; University of Pennsylvania), David E. Chavez (M-7), Gregory H. Imler (Naval Research Laboratory), and Damon A. Parrish (Naval Research Laboratory). “Polycyclic N-oxides: high performing, low sensitivity energetic materials.” Chem. Commun., 2019, 55, 2461–2464. DOI: 10.1039/C8CC09653H

Technical contacts: Christopher Snyder and David Chavez

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Physics

“Deconstructed” capsules reveal essential details for inertial confinement fusion

Three pairs of lines show simulated and experimental trajectories of the capsule ablator, in the form of the time-dependent capsule radius, P0, in micrometers.

Three pairs of lines show simulated and experimental trajectories of the capsule ablator, in the form of the time-dependent capsule radius, P0, in micrometers. Using “deconstructed” capsules (illustrated at left), the team measured the energy transferred through several layers within the capsule. Compared with the linear fit of the data, the simulated slope of the ablator-only capsule (yellow = experimental; black = simulation) shows slight differences; however, the capsule with an ablator and foam layer (blue = experimental; gray = simulation) and the capsule with ablator, foam, and inner shell (green = experimental; light gray = simulation) showed strong agreement, giving confidence that the simulations match experiment.

In research selected as an Editor’s pick for Physics of Plasmas, Laboratory scientists and collaborators presented recent experimental results on energy transfer in double-shell implosions. Their work aids efforts to achieve nuclear fusion in a Laboratory setting.

For several decades, scientists have pursued designs to compress a sphere of deuterium and tritium using lasers to create fusion energy on demand, a process known as inertial confinement fusion (ICF). Double-shell capsules hold promise due to their design; however, the complexity of the system makes them difficult to build, diagnose, and simulate.

Using a series of “deconstructed” capsules, Los Alamos researchers and external collaborators developed a new diagnostic technique to successfully measure the energy transfer between the capsule parts, using the data to validate simulation codes used for ICF experimental design.

The work was enabled by the development of an imaging shell capsule, which includes a medium-density inner shell—instead of the standard high-density inner shell—that can be used to image the inner-shell implosion with current imaging capabilities at the National Ignition Facility in Livermore, California. This new imaging capability allows researchers to measure energy transfer in future double-shell capsule designs.

The anatomy of a double-shell capsule assembly used in this experiment.

The anatomy of a double-shell capsule assembly used in this experiment.

Their work is the first to successfully measure inner-shell kinetic energy, which is essential to driving the deuterium and tritium compression required for fusion. The experimental energy coupling to the inner shell matched within a few percent of simulation prediction, giving confidence in the tools used for double-shell design. The researchers also identified a key difference between the experimental results and the simulation data, and in future work they plan to investigate whether drive asymmetry or surface roughness instabilities may account for this difference.

This work leveraged Los Alamos high performance computing and target fabrication capabilities, as well as a fabrication collaboration between LANL, General Atomics, and Lawrence Livermore National Laboratory. The experiments were performed at the National Ignition Facility.

The Inertial Confinement Fusion and High Yield Campaign (LANL Program Manager John Kline) funded the work, which supports the Laboratory’s Energy Security mission and its Nuclear and Particle Futures and Information Science and Technology science pillars.

Researchers: E. Merritt (Plasma Physics, P-24); J. Sauppe (Plasma Theory and Applications, XCP-6); E. Loomis (P-24); T. Cardenas (Engineered Materials, MST-7); D. Montgomery (P-24); W. Daughton (Primary Physics, XTD-PRI); D. Wilson (XCP-6); J. Kline (Associate Laboratory Director for Weapons Physics, ALDX); S. Khan (Lawrence Livermore National Laboratory, LLNL); M. Schoff and M. Hoppe (General Atomics); F. Fierro, R. Randolph, B. Patterson, and L. Kuettner (MST-7); R. Sacks and E. Dodd (XCP-6); W. Wan, S. Palaniyappan, S. Batha, and P. Keiter (P-24); and J. Rygg, V. Smalyuk, Y. Ping, and P. Amendt (LLNL).

Reference: “Experimental study of energy transfer in double shell implosions.” Physics of Plasma 26, 052702 (2019). https://doi.org/10.1063/1.5086674

Technical contact: Elizabeth Merritt

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Theoretical

Machine learning trains neural nets to simulate molecular motion

Computational modeling of chemical and biological systems at atomic resolution is a very valuable scientific tool; however, there is an inherent trade-off between accuracy, speed, and transferability. Researchers from Los Alamos National Laboratory, University of Florida, and University of North Carolina at Chapel Hill mitigated these issues and advanced the accessibility of computational modeling by employing machine learning, specifically transfer learning. The impact of their research is immense and will push the fields of computational biology and drug development to new frontiers. Their research was published in Nature Communications.

Diagram of the transfer learning technique evaluated in this work.

Diagram of the transfer learning technique evaluated in this work. Transfer learning starts from a pre-trained, lower-accuracy ANI-1x DFT model and then retrains to higher-accuracy CCSD(T)*/CBS data with some parameters fixed during training.

The researchers saw the limitations of current molecular modeling techniques, such as when a model is fine-tuned for one particular compound it makes it difficult to accurately transfer the simulation to a different compound. They wanted to develop a computational modeling technique that maintained accuracy when transferred to numerous compounds. To do this, the researchers trained a neural net first on a large amount of lower-accuracy data and then on a small amount of higher-accuracy data. The result was a general-purpose potential that they named ANI-1ccx. Written in a user-friendly code—Python—ANI-1ccx was made available to the public as open-source software on GitHub.

After extensive benchmarking, the researchers concluded that ANI-1ccx captures a broad range of organic chemistry, with accuracy comparable to quantum mechanics calculations at the coupled-cluster level of theory. This work offers a computationally efficient and accurate machine learning-based molecular potential for general use across a broad range of chemical systems. In short, ANI-1ccx is accurate and transferable.

Funding was provided by the LANL Laboratory Directed Research and Development (LDRD) Program. This research supports the Laboratory’s Global Security mission and the Information Science and Technology science pillar.

Reference: Justin S. Smith (LANL; University of Florida), Benjamin T. Nebgen (LANL), Roman Zubatyuk (LANL), Nicholas Lubbers (LANL), Christian Devereux (University of Florida), Kipton Barros (LANL), Sergei Tretiak (LANL), Olexandr Isayev (University of North Carolina at Chapel Hill), Adrian E. Roitberg (University of Florida). “Approaching coupled cluster accuracy with a general-purpose neural network potential through transfer learning.” Nature Communications, 2019; 10 (1) DOI: 10.1038/s41467-019-10827-4

Technical contacts: Sergei Tretiak and Justin Smith

An algorithm unravels the quantum-to-classical transition

There are differences between quantum mechanics and classical mechanics: the scale, the particle-wave behavior, and the uncertainty are some examples. Making predictions and calculations at a classical scale (e.g., Will you bowl a strike?) are based on different rules than making them on a quantum scale (e.g., How will this atom interact with that atom?), but the scale is continuous and the transition between classical and quantum is not clear-cut. Proteins exist in the transition between these disparate worlds, making them challenging to predict and study.

Los Alamos researchers created an algorithm to better understand the quantum-to-classical transition. They noted that as more particles are added to the system, the quantum effects start to go away and the system behaves more classically. The researchers’ algorithm allows one to determine how close a quantum system is to behaving classically, which is classically impossible to calculate. In their study, published in the July issue of Nature Communications, they implemented the algorithm to observe the emergence of classicality for a chiral molecule. Chiral molecules tunnel between two versions—the right-handed version and the left-handed version. In this study, the chiral molecule was considered to be in a gaseous state, so that collisions with other molecules would convey information about the chiral state and relate it to the environment. They observed the transition from a quantum regime to a classical regime, where chirality became stable.

The cost landscape for stationary histories of a chiral molecule using LANL’s quantum-to-classical transition algorithm.

The cost landscape for stationary histories of a chiral molecule using LANL’s quantum-to-classical transition algorithm. In this plot, the blue regions correspond to classical behavior. a, b show the full and partial-trace cost functions, respectively, for the case where the environment interactions are negligible. This is evidence of a quantum regime. c, d are the full and partial-trace cost functions, respectively, for the case where the environment interactions dominate. This is evidence of a classical regime.

This research is the first step in understanding and quantifying phenomena such as conformational changes (like chirality), quantum biological processes, and many more complex systems that were previously impossible to solve. As quantum computers evolve, so will algorithms like this.

This work was supported by the U.S. Department of Energy (DOE), Office of Science, Office of High Energy Physics, QuantISED program, and also by the U.S. DOE, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, Condensed Matter Theory Program. All authors acknowledge support from the LDRD program at LANL. L.C. was also supported by a J. Robert Oppenheimer fellowship. A.T.S. and P.J.C. additionally acknowledge support from the LANL ASC Beyond Moore’s Law project. W.H.Z. acknowledges partial support by the Foundational Questions Institute grant FQXi-1821 and Franklin Fetzer Fund. This research supports LANL’s Global Security mission area and Information Science and Technology science pillar.

Reference: Andrew Arrasmith (T-4; University of California Davis), Lukasz Cincio (T-4), Andrew T. Sornborger (CCS-3), Wojciech H. Zurek (T-4), and Patrick J. Coles (T-4). “Variational Consistent Histories as a Hybrid Algorithm for Quantum Foundations,” Nature Communications 10: 3438 (2019), DOI: 10.1038/s41467-019-11417-0

Technical contact: Patrick Coles

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X-Computational Physics

Progress in the physics of plasma mixing using VPIC

VPIC simulations of the Rayleigh–Taylor instability growth. Gravity is in the −x ̂ direction.

VPIC simulations of the Rayleigh–Taylor instability growth. Gravity is in the −x ̂ direction.

Plasma is created by ionizing gas atoms to form a hot mix of positively charged atomic nuclei (ions) and negatively charged electrons. Artificial plasmas, those that exist only briefly during experiments, hold the key to understanding inertial confinement fusion (ICF) and high-energy-density (HED) physics. Los Alamos scientists developed an open-source computer code VPIC (vector particle-in-cell) that simulates plasma kinetic behavior more efficiently than any other first-principles codes. VPIC models plasmas in one, two, or three spatial dimensions. As the field of supercomputing has advanced, so have VPIC’s capabilities.

In research published in the June 2019 issue of Physics of Plasmas (selected as an editor’s pick), LANL X-Computational Physics, X-Theoretical Design, High Performance Computing, and Computational Science researchers employed VPIC with a binary collision model to explore the kinetic effects of mixing of plasmas to help improve mix models in rad-hydro codes. They found that plasma kinetic effects may affect fusion yield (which is relevant to ICF experiments in general) and therefore should be accounted for when using measured deuterium-tritium (DT) and deuterium-deuterium (DD) yields to infer properties of mix morphology. These findings are particularly relevant to MARBLE experiments at the National Ignition Facility in Livermore and the Omega Laser Facility in Rochester, which focus on the interplay between mix and thermonuclear burn—important knowledge for our national and energy security.

Mix in plasmas is a combination of hydrodynamic stirring and diffusion. Electric fields at interfaces in plasmas can modify the behavior of diffusion across material boundaries. Plasma kinetic effects smear out fine structures resulting from hydrodynamics stirring and impede the growth of hydrodynamic instabilities at interfaces, especially at short wavelengths. VPIC simulations show that with plasma kinetic effects, instabilities grow more slowly, particularly for short-wavelength modes, affecting the rates of mixing in plasmas with structures on a range of spatial scales.

This research supports the Laboratory’s Nuclear Deterrence and Global Security mission areas and the Information Science and Technology science pillar. This work was supported by the LANL Advanced Simulation and Computing (ASC) program. VPIC simulations were run on ASC Trinity supercomputer under Capability Class Computing and the Large Scale Calculations Initiative (LSCI).

Reference: Lin Yin (XCP-6), Brian Albright (XTD-PRI), Erik Vold (XCP-2), William D. Nystrom (HPC-ENV), Bob Bird (CCS-7), and K. J. Bowers. "Plasma kinetic effects on interfacial mix and burn rates in multi-spatial dimensions." Physics of Plasmas, 26, 062302 (2019); https://doi.org/10.1063/1.5109257

Technical contact: Lin Yin

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