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Los Alamos National Laboratory

Los Alamos National Laboratory

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Science Highlights, February 22, 2017

Awards and Recognition

John Yeager wins Presidential Early Career Award

John Yeager

John Yeager (High Explosives Science and Technology, M-7) received a Presidential Early Career Award for Scientists and Engineers. The Awards are intended to encourage and accelerate American innovation to grow our economy and tackle our greatest challenges. The Presidential Early Career Award is the highest honor bestowed by the U.S. government on outstanding scientists and engineers in the early stages of their independent research careers. Yeager is among 102 scientists and engineers from 12 government agencies who received this year’s awards. President Obama presented the awards while he was in office. Full list of winners here.

Yeager’s work employs unique user facility capabilities, such as the Los Alamos Neutron Science Center (LANSCE), to address pressing national-security needs. It is an example of science on the roadmap to MaRIE, the Laboratory’s proposed experimental facility to combine x - ray and neutron-scattering methods for unprecedented, time-resolved access to structural properties of materials from atomic- to meso-scales.

Yeager earned a PhD from Washington State University. He began working at Los Alamos during his doctoral studies in 2009 and continued his research at the Laboratory as an Agnew National Security Postdoctoral Fellow . The Lab converted him to a technical staff member in 2013.

His research at the Laboratory has focused on microstructur e characterization and mechanical properties of plastic-bonded explosives and other energetic materials. To accomplish this, he has collaborated with a large number of separate groups, internal and external to LANL, including the Lujan Center at LANSCE, the Center for Integrated Nanotechnologies (CINT), Purdue University, the University of Minnesota, the Advanced Photon Source at Argonne, and the U .S. Army Research Laboratory at Aberdeen. His experimental research ranges from thin films and interfaces to larger scale materials properties such as crystallographic texture, detonation performance, and microstructural evolution during compression or fracture. This work includes studies of the crystallization of melt-castable energetics, initiation o f explosive pellets from aluminum fragment impact, and the influence of a plasticizer on explosive -binder interfaces.

Yeager leads a research program using in situ probes to understand how the meso-structure of explosives affects their performance and s afety. The performance of explosives is important to a variety of the Laboratory’s missions . Cracking in explosives can lead to subsequent safety or performance questions. Materials modeling efforts for explosives have recognized the importance of understanding interfacial strength in the composites for more than 10 years . Despite significant efforts, this property had not been measured accurately. Yeager’s work revealed the property for the first time, and also connected back to materials and formulation methods that could be altered to accommodate for specific materials needs.

Yeager’s honors include the Laboratory’s Agnew National Security Fellowship, NNSA Defense Programs Award of Excellence, and Los Alamos Award Program (LAAP) for his role in the development of the IMPULSE capability at the Advanced Photon Source. He has received a Laboratory Directed Research and Development (LDRD) Early Career Research project.

The Presidential Early Career Award for Scientists and Engineer awards, established by President Clinton in 1996, are coordinated by the Office of Science and Technology Policy within the Executive Office of the President. Awardees are selected for their pursuit of innovative research at the frontiers of science and technology and their commitment to community service as demonstrated through scientific leadership, public education or community outreach. U.S. departments and agencies , including the DOE, nominate the most meritorious scientists and engineers whose early accomplishments show the greatest promise for assuring America’s preeminence in science and engineering and contributing to the awarding agencies ’ missions. Technical contact: John Yeager

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George “Rusty” Gray elected to National Academy of Engineering

George Gray III

The National Academy of Engineering (NAE) has chosen George “Rusty” Gray III (Materials Science in Radiation and Dynamic Extremes, MST-8) to be a member. The NAE cited him for “contributions to the understanding of the dynamic and shock -loading deformation and damage response of materials.” Election to the NAE is among the highest professional distinctions an engineer can attain.

Gray received a PhD in metallurgical engineering from Carnegie Mellon University, and joined Los Alamos in 1985. He pursues fundamental and applied research to elucidate the structure and property behavior of materials subjected to dynamic and shock -wave deformation. Gray investigates the structure/property behavior of materials under extreme conditions and the development and validation of predictive models of the strength and damage behavior of materials.

Gray is a fellow of Los Alamos National Laboratory, ASM International, American Physical Society, and the Minerals, Metals and Materials Society (TMS). He has been a visiting fellow at Cambridge University and a visiting scholar at the University of California – San Diego. Gray has served on several National Academies of Sciences advisory boards and panels, chairs Acta Materialia ’ s board of governors, and is an adjunct professor at Ohio State University. In 2010, he served as the president of TMS. Gray has received a Los Alamos National Laboratory Fellows Prize, two Individual Distinguished Performance Awards, and an Award for Excellence in Technology Transfer.

NAE elected 84 new members and 22 foreign members this year, bringing the total United States membership to 2,281 and foreign membership to 249. Membership honors those who have made outstanding contributions to “engineering research, practice, or education, including, where appropriate, significant contributions to the engineering literature” and to “the pioneering of new and developing fields of technology, making major advancements in traditional fields of engineering, or developing/implementing innovative approaches to engineering education.”

The NAE is part of the National Academies of Sciences, Engineering, and Medicine. The NAE operates under the same congressional act of incorporation that established the National Academy of Sciences, signed in 1863 by President Lincoln. Under this charter the NA E is directed “ whenever called upon by any department or agency of the government, to investigate, examine, experiment, and report upon any subject of science or art.” NAE’s mission is to advance the well being of the nation by promoting engineering and marshaling the expertise and insights of eminent engineers to provide independent advice to the federal government on matters of engineering and technology. Technical contact: George Gray III

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Nathan Mara recognized with a Young Researcher Award

Nathan Mara

The International Journal of Plasticity has selected Nathan Mara (Center for Integrated Nanotechnologies, MPA -CINT, and the Nanoscale Science and Engineering Center’s Institute for Materials Science) for a Young Researcher award. The award honors his contributions to the field of plasticity, especially modeling plastic deformation and the mechanics of metals and nanocomposites. Award recipients are selected for a combination of publication citations , service to the journal, and overall quality of research and impact on the deformation plasticity field.

Mara is the CINT nanoscale electronics and mechanics thrust co -leader and co-deputy director of the Lab’s Institute for Materials Science. He focuses on the relationship between microstructure and mechanical behavior across length scales from the atomic to bulk. Mara’s research emphasizes manufacturing bulk nanocomposite material for structural applications in extreme environments. This work combines materials synthesis, mechanical testing, and materials characterization techniques using microstructural analysis tools at CINT and the Laboratory.

Mara has a PhD in materials science and engineering from the University of California – Davis. He joined Los Alamos as a Director’s Postdoctoral Fellow and became a staff scientist in 2008. Mara is past chairman of the Nanomechanical Materials Behavior Committee of The Minerals, Metals, and Materials Society (TMS) and received the 2012 TMS Young Leaders Professional Development Award. He won the Laboratory Distinguished Mentor Performance Award for his dedication to undergraduate and graduate student education at Los Alamos.

Mara’s work supports the Lab’s Energy Security and Global Security missions and the Materials for the Future science pillar through developing lightweight structural materials with enhanced performance under extreme environments, advanced structural materials for use in nuclear reactor applications, and new test methodologies for investigating the mechanica l behavior of materials across length scales. CINT is a Nanoscale Science Research Center managed under the aegis of the DOE Office of Science and jointly operated by Los Alamos and Sandia as a national user facility.

Mara received the award at the 2017 International Symposium on Plasticity and its Current Applications. Technical contact: Nathan Mara

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Brad Ramshaw selected for Lee Oscheroff Richardson Science Prize

Brad Ramshaw

Oxford Instruments has chosen Brad Ramshaw (formerly of Condensed Matter and Magnet Science, MPA-CMMS and currently at Cornell University) to receive the 2017 Lee Oscheroff Richardson Science Prize. The honor recognized him “for his outstanding contributions to the exploration of correlated electron systems in extreme magnetic f ields.” Oxford Instruments presents the award annually to young scientists conducting low temperature, high magnetic field, or surface science research in North and South America. A committee of leading physicists from North and South America selected Ramshaw, who will be recognized during a special event by the United Kingdom manufacturing and research company at the American Physical Society (APS) March Meeting.

Ramshaw earned a PhD in physics from the University of British Columbia, and then joined the Lab in 2012 as a postdoctoral researcher at the National High Magnetic Field Laboratory -Pulsed Field Facility (NHMFL-PFF). There he used ultrasound spectroscopy and pulsed field transport to study high-Tc and heavy fermion superconductors. LANL named him a Director’s Postdoctoral Fellow in 2013, and converted him to a staff scientist in 2015. Ramshaw is now an assistant professor at Cornell University. He remains a close collaborator with the MPA-CMS’s topology and correlations Laboratory Directed Research and Development (LDRD) project and is an active user of the NHMFL-PFF.

According to nominator Ross McDonald, Ramshaw has built an internationally prominent record of research in quantum materials. As examples McDonald cited Ramshaw’s publication of the “Angle Dependence of Quantum Oscillations in YBa2Cu3O6.59 Shows Free-Spin Behavior of Quasiparticles” in Nature Physics; his Proceedings of the National Academy of Science reporting an “Avoided Valence Transition in a Plutonium Superconductor,” and his Science paper “Quasiparticle Mass Enhancement Approaching Optimal Doping in a High-Tc Superconductor.” These high-profile publications, for which Ramshaw was nominated, involved research that was uniquely available at Los Alamos through access to the world’s strongest magnetic fields and superconducting plutonium compounds. Technical contact: Ross McDonald

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Joanne Wendelberger honored as the W. J. Youden Memorial Address Speaker

Joanne Wendelberger

The 60th annual American Statistical Association (ASA) Fall Technical Conf erence honored Joanne Wendelberger (Statistical Sciences, CCS-6) as this year’s W. J. Youden Memorial Address speaker. Her address, “Understanding Today’s Complex World,” explored the role of sampling, error analysis, and statistical experiment design in addressing complex problems and the associated evolution of statistical methods over time. She also presented “Statistical Methods for Data Science,” during an invited session.

The ASA chooses the Youden address speaker based on the following criteria: must be a recognized leader in the development or application of statistical methodologies, extensively promote statistics and statistical applications to everyday problems, be published, and be a vibrant and passionate speaker.

Wendelberger joined the Lab in 1992 after receiving a PhD in statistics at the University of Wisconsin - Madison and working at the General Motors Research Laboratories. Her research focuses on the statistical design of experiments, statistical bounding and quantification of uncertainty, material aging and degradation, statistical issues in cybersecur ity, sampling problems in large-scale computation and visualization, and education modeling. She is a Fellow of the ASA. Technical contact: Joanne Wendelberger

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R. Picard, M. Hamada, G. Hemphill, and R. Hackenberg receive Søren Bisgaard Award

R. Picard

Rick Picard

The 60th annual American Statistical Association Fall Technical Conference selected Lab researchers Rick Picard, Michael Hamada, and Geralyn Hemphill (Statistical Sciences, CCS-6); and Robert Hackenberg, (SIGMA Division, SIGMA-DO) to receive the Søren Bisgaard Award for their paper, “Accounting for Nonrandomly Sampled Data in Nonlinear Regression,” published in Quality Engineering. Picard accepted the award on behalf of the co-authors.

The Bisgaard Award annually recognizes the paper in the American Society for Quality journal, Quality Engineering , with the greatest potential for advancing the practice of quality improvement. The Award is named in memory of Søren Bisgaard, Isenberg Professor of Management at the University of Massachusetts -Amherst and an international expert on quality management and applied statistics.

The Lab researchers analyzed data that are “ch erry picked” (i.e ., nonrandomly sampled) from a population. The investigators used the data for regression modeling and prediction. Nonrandom data are encountered in numerous situations, and the application of standard statistical methods developed for random samples can easily lead to incorrect conclusions. The paper presented a case study to illustrate the related issues and the repercussions of erroneously ignoring the nonrandom sampling. The case study described a situation involving a manufactured product where the consequences of biased estimation are costly. The authors concluded that it is essential to account for the nonrandom sampling, lest the analysis produce erroneous conclusions. Formal methods exist for this purpose.

Reference: Quality Engineering 27 , (2) 168 (2015); doi: 10.1080/08982112.2014.933979.

Technical contact: Rick Picard

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Bioscience

Whole genome relationships among Francisella bacteria of diverse origin

  Scanning    electron    micrograph    of    a    murine    macrophage    infected    with     Francisella    tularensis strain     LVS

Figure 1. Scanning electron micrograph of a murine macrophage infected with Francisella tularensis strain LVS . Macrophages were dry -­‐fractured by touching the cel l surface with cellophane tape after critical point drying to reveal intracellular bacteria. Bacteria (colorized in blue) are located either in the cytosol or within a membrane -­‐ bound vacuole. Credit: NIAID

Francisella tularensis is a highly virulent zoonotic pathogen that causes tularemia, a rare but serious disease that infects humans and animals in the Northern Hemisphere. Approximately 125 tularemia cases are reported annually. Due to weaponization efforts in past world wars, F. tularensis is considered a Tier 1 biothreat agent, and detection and surveillance of its prevalence are critical. The Francisella genus is incredibly diverse. Francisella spp. have been isolated from a wide variety of clinical and environmental sources and include highly virulent human and animal pathogens, fish pathogens, opportunistic human pathogens, tick endosymbionts, and free- living organisms inhabiting brackish/seawater environments and industrial cooling towers. A number of Francisella genomes have been sequenced to date, but the species relationships among members of this genus have been difficult to resolve. Los Alamos researchers compared 31 Francisella genomes, designating four new species and providing a robust framework to distinguish species and virulence features of newly detected Francisella bacteria. The journal Applied Environmental Microbiology published their findings.

Scientists traditionally categorized organisms based on their physical characteristics and functions. In recent decades, DNA-based detection and sequencing has become useful for distinguishing pathogens from other, closely related organisms. However, identifying these “near neighbors” is often only possible when there are DNA sequences available for comparison. To improve this endeavor, Laboratory researchers, led by Cheryl Kuske (Bioenergy and Biome Sciences, B-11), are using DNA markers to identify related but relatively harmless Francisella species and to provide a means to distinguish them from the harmful F. tularensis.

The Applied Environmental Microbiology paper describes the Lab team’s large study, which is particularly notable for having used 31 publicly available genomes plus select genes from about 90 additional isolates. However, the work goes further than examining sequence data alone. It includes evaluating the environments where the isolates are found and the phenotypes of the organisms in order to develop a comprehensive, genomics-based understanding of organisms and their environment.

Through detailed genome comparisons, sequence-alignment algorithms and other bioinformatics tools, the Los Alamos team identified features that differentiate among F. tularensis and other novel clinical and environmental Francisella isolates. This information provides a knowledge base for comparison of new sequences from clinical or environmental surveys. As a result of this analysis, the researchers designated four new species groups within the genus: Francisella opportunistica, an opportunistic pathogen of immune compromised patients; Francisella salina and Francisella uliginis, environmental isolates from coastal seawater near Galveston, TX; and Francisella frigiditurris from cooling-tower water in California.

 Panel    A,    phylogenetic    tree    based    on    the    sdhA    gene    from    92     Francisella     isolates.

Figure 2. Panel A, phylogenetic tree based on the sdhA gene from 92 Francisella isolates. Except for the F. tularensis subsp. mediasiatica clade, the branches representing the F. tularensis clades showed low bootstrap support values (much less than 50%) at the tips . Therefore, the team collapsed some branches with low support (generally less than 10%) for easier viewing of the overall relationships. Panel B, phylogenetic tree based on a set of 36 protein markers. Because the focus of this paper is on the F. novici da -­‐like genomes and the potentially new species, the authors did not include all F. tularensis isolates in this tree, just one representative from each subspecies. The red and green squares denote major branches of the trees. The team collapsed minor branches with low bootstrap support values (generally under 10, indicating identical or nearly identical sequences) to make this figure easier to view.

The value of having more identification tools available is especially evident in areas such as the Southwest, where tularemia outbreaks are endemic and potentially life threatening. Being able to identify the specific organism quickly and accurately is critical when dealing with an outbreak. The global distribution of the Francisella isolates suggests a worldwide distribution of Francisella organisms that inhabit fish, ticks and a variety of environmental sources.

Reference: Whole Genome Relationships among Francisella Bacteria of Diverse Origin Define New Species and Provide Specific Regions for Detection, Applied Environmental Microbiology 83, e02589 (2017); doi: 10.1128/AEM.02589-16. Authors: Jean F. Challacombe (Biosecurity and Public Health, B-10), Jeannine M. Petersen, La Verne Gallegos - Graves, David Hodge, Segaran Pillai, Cheryl R. Kuske (B-11).

The U.S. Department of Homeland Security, Science and Technology Directorate funded the research, which supports the Lab’s Global Security mission area and the Science of Signatures science pillar through the identification of pathogens. Technical contact: Cheryl Kuske

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Capability Enhancement

Development of the capability to measure neutron total cross sections

In early 2016, researchers began work to demonstrate the capability to constrain neutron capture cross sections tightly via resonance analysis of neutron total-cross-section measurements. Neutron capture cross sections for many short-lived and very rare stable isotopes are of vital importance for nuclear energy and defense technologies, as well as nuclear astrophysics. Because direct neutron-capture measurements of these rare nuclides are extremely difficult or impossible, very few have been made.

In contrast, total cross sections measurements on these same nuclides should be feasible and yield tight constraints on the needed capture cross sect ions. Lab researchers are adapting a former materials flight path, Flight Path 13, at the LANSCE Lujan Center for this purpose.

Their f irst test measurements revealed that the background must be reduced substantially to enable the sensitivity required for the planned measurements . The team identified and made improvements to the apparatus. This included adding new collimation, lengthening the flight path to accommodate an improved beam stop further from the detector, realigning beam-line components, and fielding an improved detector.

Figure 3 depicts the transmission spectra (transmission T is related to the total cross section) over three different energy regions taken with a thulium (Tm) sample. Blue circles and red Xs depict data taken before and after, respectively, the improvements mentioned above. The sol id curve shows the expected transmission calculated with the R-matrix program SAMMY using resonance parameters from the latest ENDF evaluation. The top third of the figure shows data near the bottom of a “black” resonance. (A black resonance scatters or absorbs almost all neutrons in a narrow energy range.)

Figure    3.    Transmission    spectra    over    three    different    energy    ranges    taken    with    a    90    mg/cm 2     thulium    sample.

Figure 3. Transmission spectra over three different energy ranges taken with a 90 mg/cm 2 thulium sample.

The improvements lowered the background, enabling very good agreement with expectations. The middle and bottom thirds of the Figure show regions near smaller resonances. The reduction in background enhanced the team’s ability to detect small resonances. Success of the technique depends on the ability to accurately determine parameters f or as many resonances as possible. The data in demonstrate that the improvements to Flight Path 13 greatly improved the measurement capabilities.

Researchers include Aaron Couture, Paul E. Koehler, Shea Mosby, and Principal Investigator John L. Ullmann (LANSCE Weapons Physics, P-27).

Koehler presented the work, “Improved Nuclear Forensics, Radiochemical Diagnostics, and Nuclear Astrophysics via Total-Cross-Sectio ns Measurements at the Los Alamos Neutron Science Center,” at the 24th International Conference on the Application of Accelerators in Research and Industry, in Fort Worth, TX. NNSA Science Campaign 4 (LANL Program Manager Melissa Douglas) funded the work, which supports the Laboratory’s Nuclear Deterrence mission area and the Nuclear and Particle Futures and Science of Signatures science pillars via improved nuclear data and nuclear theory. Technical contact: Paul Koehler

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Chemistry

Tritium science for the ITER project

Figure     4.    Radiograph    of    STACI    inner    vessel    showing    band    heaters    and    electrical    connectors,    stainless    steel    vessel     wall,    copper    wells    and    cubes    of    depleted    uranium    metal.

Figure 4. Radiograph of STACI inner vessel showing band heaters and electrical connectors, stainless steel vessel wall, copper wells and cubes of depleted uranium metal.

The International Thermonuclear Experimental Reactor (ITER) is an international project to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes. ITER has a “tokamak” design that uses a deuterium-tritium plasma fuel. The Laboratory designed the Self Assaying Tritium Accountability and Containment Unit (STACI) for the ITER project over 15 years ago at the Tritium Station Test Assembly (TSTA) facility. Thanks to new funding, the design is now being tested experimentally.

The storage, measurement and controlled delivery of tritium are required in the fuel cycle of ITER. In this Los Alamos-led project, researchers designed and constructed a metal hydride getter bed to study the containment and control led delivery of tritium. A self-assaying feature maintains accurate accountability with minimum handling of the tritium. The self -assay feature measures the decay heat of stored tritium in a primary container that is thermally isolated from the ambient environment. The investigators tested the feature after the initial development. Recent funding from DOE Office of Science Fusion Energy Sciences and ITER has enabled Lab chemists to continue testing of the LANL design. The storage bed is composed of 5.261 kg of depleted uranium (DU). The simple design employs bed segments that are small in size and do not require radiation shields. The operating capacity of the bed is 150 grams of tritium (T2), with a total capacity of 200 grams of tritium.

In the recent experiments, the researchers examined the performance of STACI unit for loading, storage and delivery operations using hydrogen (H2) as a surrogate for tritium. The team performed a series of experiments to study the operational characteristics and perf ormance of the design and the effects of the bed material The studies included the conditioning of the uranium bed, hydride and dehydride performance, pressure drop across the hydrided and dehydrided bed, containment of the powdered uranium bed material, efficiency of the bed to separate mixtures of hydrogen and inert gas , and radiographic examination of the uranium bed. The team completed the initial studies and is upgrading the unit to further the design of the unit. The data from these experiments support the ongoing design work for the ITER Storage and Delivery System (SDS).

Chemical Diagnostics and Engineering (C-CDE) researchers include Dave Dogruel and Brian Arko, and Kirk Hollis leads the project. The DOE Office of Science, Fusion Energy Sciences and ITER funds the work, which supports the Laboratory’s Energy Security mission area and the Mate rials for the Future science pillar through the development of technologies for clean energy generation. Technical contact: Kirk Hollis

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Earth and Environmental Sciences

Studies reveal new understanding of the Jemez Mountain volcanic field

Giday    WoldeGabriel    examines     a    volcanic    outcrop

Giday WoldeGabriel examines a volcanic outcrop

Two recent publications on volcanic eruptions provide more insight into the young and complex region of volcanic activity that surrounds the Laboratory. The Lab lies within the Jemez Mountain volcanic field, which has erupted volcanic materials during the Quaternary (i.e., the last 2.6 million years). The youngest eruptions are associated with the Valles Caldera and occurred as recently as approximately 50,000 years ago. In addition, LANL is bordered on the east by the Cerros del Rio volcanic field, which has also erupted during the Quaternary. Volcanic activity and eruptions are a primary natural phenomena hazards element within DOE regulatory drivers, and current and future LANL facility performance goals may be affected by future volcanic eruptions . Therefore, a more detailed understanding of the volcanic regime is needed.

New Mexico Geology published an overview of the youngest silicic eruptions from the Valles Caldera and the subsequent implications for volcanic hazard potential in north -central New Mexico. The work is a summary of a Laboratory report titled “Geochemistry, Extent, Signatures, and Chronology of Basaltic and Young Silicic Pyroclastic Eruptions: Refining Existing Date to Support a Future Volcanic Hazard Assessment of LANL”. The research includes recent geochronology age-dating results.

The Jemez Mountains volcanic field represents volcanic activity that formed as a result of mantle heating initiated by extension of the Rio Grand rift. Several volcanic eruption episodes crop out within the volcanic field, ranging in age from 25.5 Ma to 68.3 ka. The El Cajete Pyroclastic Beds, Battleship Rock Ignimbrite, and Banco Bonito obsidian flow are the youngest of these. The El Cajete Pyroclastic Bed is much more widespread than the other two units, with outcrops as far as 30 km southwest of the eruption center.

Prior age-dating work had yielded a wide range of results (less than 40 ka to more than 1.24 Ma). The new argon-40/argon-39 isotope and uranium/thorium dating methods have constrained the ages of these eruptive units. The El Cajete Pyroclastic Beds and co -erupted Battleship Rock ignimbrite are approximately 74.4 ka, and the Banco Bonito obsidian flow was dated to 68.3 ka. The team concludes that these young eruptions do not appear to pose imminent volcanic concerns. The larger concern is likely the low -velocity zone beneath the western Valles Caldera. The higher percentage of melt in this zone could present a potential new pulse of magma. The Los Alamos Seismic Network (LASN) has not detected unusual volcano -seismic activities since the monitoring system was established in the 1970s, and sustained monitoring will provide notification of any systematic changes in the magmatic r eservoir.

Reference: “The Youngest Silicic Eruptions from the Valles Caldera and Volcanic Hazard Potential in North-Central New Mexico,” New Mexico Geology 38 , issue 2, 50 (2016). Authors: Giday WoldeGabriel, Rick Kelley, Elizabeth Miller, and Emily Schultz-Fellenz (Earth Observations, EES-14).

Figure     5.    Outcrop    extent    of    the    El    Cajete    Pyroclastic    Beds.    Red    asterisk    is    the    El    Cajete    vent,    and    orange    shading     represents    the    approximate    spatial    extent    of    the    El    Cajete    deposit.     Tan    shading    depicts    the    Laborat ory    boundary. Thick    black    lines    represent     unconcealed    faults.

Figure 5. Outcrop extent of the El Cajete Pyroclastic Beds. Red asterisk is the El Cajete vent, and orange shading represents the approximate spatial extent of the El Cajete deposit. Tan shading depicts the Laborat ory boundary. Thick black lines represent unconcealed faults.

The Journal of Volcanology and Geothermal Research published the second article. The research reports volcanism and sedimentation along the western margin of the Rio Grande rift through a detailed look at the Cerro Toledo Formation, which is a complex series of eruptions that occurred along the western margin of the Rio Grande Rift between the major caldera - forming eruptions of the Bandelier Tuff 1.65-1.26 Ma.

The study uses field mapping and observations, stratigraphy, geochemistry, and geochronology to present new information about the depositional history and setting of tephras and epiclastic sediments that make up the Alamo Canyon and Pueblo Canyon Members of the Cerro Toledo Formation. Despite deposition within a few kilometers of each other on the Pajarito Plateau, these two members differ significantly. These differences highlight spatial distinctions in vent sources, eruptive styles, and depositional environments along the eastern side of the Jemez Mountains volcanic field during this approximately 400,000 year interval. The Alamo Canyon Formation exhibits a very narrow range in composition as compared with fall deposits from the Pueblo Canyon Formation. The information indicates that a single eruption source produced the Alamo Canyon Formation. New dates, when analyzed in conjunction with a reassessment of local stratigraphy, indicate that multiple vents became active within less than approximately 100,000 years after the end of the Toledo Caldera-forming eruptions. Activity continued until immediately prior to the Valles Caldera -forming eruptions (1.65 to 1.26 Ma).

Figure     6.    Structure    contour    map    of    the    Otowi    Member    surface    and     the       hypothetical    location    of    the     ancestral    Rio     Grande    based    on    data    modified    from    previous    studies.    The    black    arrow    marks    the    axis    of    a    south -­‐draining    paleovalley    incised    into    the    Otowi    Member.    Inset    map    shows    the    location    of    the    Jemez     Lineament    (JL)    and    the    Rio    Grande    Rift    (RGR).

Figure 6. Structure contour map of the Otowi Member surface and the hypothetical location of the ancestral Rio Grande based on data modified from previous studies. The black arrow marks the axis of a south -­‐draining paleovalley incised into the Otowi Member. Inset map shows the location of the Jemez Lineament (JL) and the Rio Grande Rift (RGR).

The study also correlated volcanic units across a number of locations and drillholes : Alamo Canyon, SHB-3 (a seismic hazards drill hole), R-26 (an Environmental Programs groundwater monitoring well), and Pueblo Canyon. These analyses enabled the construction of structure contour maps of the Otowi Member surface, Cerro Toledo Formation surface, and the hypothetical location of the ancestral Rio Grande River. Together these two surfaces provide a representation of landscape evolution during the interlude betwe en caldera-forming eruptions. The eruption and erosion of the Otowi formed a south to southeast paleovalley that drained to the ancestral Rio Grande, and continued local erosion occurred in many places before deposition of the Cerro Toledo Formation. The top surface of the Cerro Toledo Formation records the landscape just prior to the eruption of the Tshirege Member of the Bandelier Tuff.

Reference: “Volcanism and Sedimentation Along the Western Margin of the Rio Grande Rift Between Caldera-forming eruptions of the Jemez Mountains Volcanic Field, North-central New Mexico, USA,” Journal of Volcanology and Geothermal Research 327, 416 (2016); doi: 10.1016/j.volgeores.2016.09.012. Authors: Elaine P. Jacobs and Giday WoldeGabriel (EES-14), Shari A. Kelley (New Mexico Institute of Mining and Technology), David Broxton (Environmental Services, ES -ER), and John Ridley (Colorado State University).

The DOE Environmental Management Program funded the work, which supports the Laboratory’s mission areas and the Science of Signatures science pillar. The Volcanic Hazards Assessment Program aims to better understand the extent and potential damage associated with a volcanic eruption. The goal is to characterize geologic systems such that Laboratory facilities can be constructed in a better, safer fashion to protect from geologic hazards. Technical contacts: Giday WoldeGabriel and Elaine Jacobs

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Materials Physics and Applications

Unusual resistivity-temperature relationship found in high temperature superconductors

    A    quantum    critical    point    where    th e    scattering    can    be    set    by    two    independent    parameters,    competing    to     set    the    overall    scale.

Figure 7. A quantum critical point where th e scattering can be set by two independent parameters, competing to set the overall scale. The magnetic field and temperature play identical roles in setting the energy scale of the scattering, such that they appear T -­‐linear at small B (red region), and B-­‐ linear at small T = 0 (blue region). The data suggest that it is more useful to understand this physics as a balance of the two scales. The s chematic representation of the relationship between T, H illustrates the quantum critical plane as a function of te mperature, field, and composition.

A research team that included Ross McDonald (Condensed Matter and Magnet Science, MPA - CMMS) has pinpointed a correlation between resistivity and temperature in the iron pnictide superconductor BaFe 2 (As1— x Px ) 2 . The investigators found an unexpectedly simple scaling relationship between applied magnetic field and temperature. The findings provide an important clue towards future understanding of the strange metal stat e in high-temperature superconductors and related strongly correlated metals . The results suggest the possibility of a new route to explore quantum criticality using high magnetic fields. Nature Physics published the research.

The resistivity of many exotic metallic systems varies linearly with temperature, which is phenomenologically related to high -temperature superconductivity in both the cuprates and iron pnictides. It is not clear how the relevant physics manifests in other transport properties, for example their response to an applied magnetic field.

The team investigated BaFe 2 (As1— x Px ) 2 using the National High Magnetic Field Laboratory (NHMFL) Pulsed Field Facility at Los Alamos, which provided magnetic fields of up to 92 T. There are only a few places in the world where researchers can access this range of magnetic field strength. These high fields enabled the researchers to destroy superconductivity, revealing that the unconventional linear resistivity is simply set by the energy scale of the thermal energy and applied magnetic field added in quadrature. The results demonstrated that the scaling factor between temperature and magnetic field is simply Boltzmann’s constant and the Bohr magneton.

Reference: “ Scaling between Magnetic Field and Temperature in the High-Temperature Superconductor BaFe 2 (As1-x Px) 2 ,” Nature Physics , doi: 10.1038/NPHYS3773. Authors: Ian Hayes, Nicholas Breznay, Toni Helm, and James Analy tis (University of California – Berkeley and Lawrence Berkeley National Laboratory); Philip J.W. Moll (University of California – Berkeley); Ross D. McDonald (MPA-CMMS); Mark Wartenbe and Arkady Shekhter (Florida State University).

The National Science Foundation and the DOE’s Basic Energy Science-Science of 100 Tesla program sponsored the Los Alamos portion of the work, which was completed at the NHMFL Pulsed Field Facility. Brad Ramshaw (MPA-CMMS) and the 100 Tesla operations team provided scientific and technical support. The research supports the Laboratory’s Energy Security mission area and the Materials for the Future science pillar. Technical contact: Ross McDonald

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Materials Science and Technology

The effect of distribution of a second phase on dynamic damage in alloys

Many industries require materials that can tolerate extensive damage during dynamic lo ading. In order to design materials with specific responses to dynamic damage, it is important to understand the effect of microstructure on its spall response. The majority of materials used in engineering applications are multiphase alloys . The concentration and distribution of a second phase within a primary metal matrix can affect and control the dynamic response of a material. Los Alamos researchers investigated the effect of processing related to the distribution of a soft second phase in a multiphase alloy. They used copper (Cu) with a second soft phase of lead (Pb) to examine the effect of the second phase distribution on damage nucleation and evolution. The Journal of Applied Physics featured the research on its cover.

Figure     8.    The    cover    of    the     Journal    of    Applied    Physics     featured    research    into    the    dynamic    fracture    of    engineered     materials.     The    top    images    correspond    to    the    inverse    pole    figure    maps    of    the    annealed    extruded    CuPb    ( left )    and homogenized    CuPb    ( right ).    The    black    spots    in    the    CuPb    inverse    pole    figure    represent    Pb    particles.    The    bottom     images    are    the    textures    associated    with    these    microstructures.

Figure 8. The cover of the Journal of Applied Physics featured research into the dynamic fracture of engineered materials. The top images correspond to the inverse pole figure maps of the annealed extruded CuPb ( left ) and homogenized CuPb ( right ). The black spots in the CuPb inverse pole figure represent Pb particles. The bottom images are the textures associated with these microstructures.

The study aimed to understand the effects of the distribution of a second soft phase on damage nucleation and evolution, a previously unexplored side of the problem. The investigators examined two copper (Cu) alloys, each with 1% lead (Pb) materials , but with different Pb distributions. The team cast a new CuPb alloy with a more homogeneous distribution of Pb, and compared it with an extruded heterogeneous CuPb alloy where the Pb congregated in large “stringer” type configurations. Researchers shock loaded the material at approximately 1.2 GPa and then soft recovered them.

The in situ free surface velocity information and post mortem metallography studies revealed that although the spall strength of both the materials was similar, the total extent and details of damage in the materials varied by 15%. Metallography showed significant differences in the total extent of nucleated damage and the morphology of the voids. The homogenized CuPb alloy had a 3% higher number of voids that are about 7 times larger in diameter as compared with the extruded alloy. The authors suggest that altering the Pb distribution increases the number of Cu- Pb interfaces (weak links where voids nucleate) , leading to a larger number of voids in the homogenized CuPb alloy. The team attributed the smaller size of voids in the extruded CuPb to the dissipation of energy required to grow the voids through plastic work in Pb (which is much softer) rather than in deforming the Cu matrix. For the voids to grow, the surrounding matrix must plastically deform. The data suggest that altering the Pb distribution changes the number of Cu-Pb interfaces and the size of the Pb precipitates. This directly controls void nucleation and growth. This work demonstrates when and how a soft, second phase can significantly affect strength and failure properties of a material.

Reference: “The Effect of Distribution of Second Phase on Dynamic Damage,” Journal of Applied Physics 120 , 085901 (2016); doi: 10.1063/1.4961041. Authors: S. J. Fensin, D. R. Jones, D. T. Martinez, G. T. Gray III, and E. K. Cerreta (Materials Science in Radiation & Dynamics Extremes, MST-8); E. K. Walker and A. Farrow (Manufacturing Science and Engineering, MET - 2); S. D. Imhoff and K. Clarke (Sigma); and C. P. Trujillo (Nuclear Materials Science, MST -16).

The NNSA Science Campaign 2 (program manager Dana Dattelbaum) and the DoD/DOE Joint Munitions Program (LANL program manager Tom Mason) funded the work, which supports the Lab’s Nuclear Deterrence and Global Security mission areas and the Materials for the Future science pillar. Such research could be advanced by collecting in situ data, a capability that MaRIE, the Laboratory’s proposed facility for time-dependent control of the dynamic properties of materials, could make possible. Technical contact: Saryu Fensin

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Physics

First Entropy Engine quantum random number generator reaches the market

Whitewood Encryption Systems’ quantum random number generator serial number 00001 shipped recently, marking the technology’s debut as a commercial product available for cybersecurity applications. The technology is based on quantum cryptography inventions originally developed at Los Alamos and licensed to Whitewood. A joint R&D 100 entry from the Lab and Whitewood won a 2016 R&D 100 Award, which honors the top 100 proven technological advances of the past year as determined by a panel selected by R&D Magazine.

Developed in partnership between the Laboratory and Whitewood, the device is a plug-and-play card that fits network servers and strengthens the foundation of computer security by creating truly random numbers at a rate up to 200 million bits each second. It can deliver these numbers on-demand over a network to existing encryption applications and devices performing cryptographic operations across datacenters, cloud computing systems, mobile phones, and the Internet of things. Marketed under the name Entropy Engine, it produces random bits with the strongest security assurances and at the highest rates of any hardware random number generator on the market today.

The final product as it is prepared for shipment

The final product as it is prepared for shipment

The invention addresses a key fundamental flaw in modern crypto systems: predictability. Entropy Engine uses the unique properties of quantum mechanics to generate true entropy (random numbers) in a way that makes it immune from external influences. The behavior of the universe at the smallest scale–the quantum level–is fundamentally unpredictable and beyond the influence of any adversary. The new technology supplies a flood of trustworthy, verifiable truly random numbers, making it virtually impossible for even the most sophisticated cyber attackers to break into the assets protected by this technology. 

Researchers: Raymond Newell and Glen Peterson (Applied Modern Physics, P-21), David Guenther (Space Electronics and Signal Processing, ISR-4), Richard Moulds (Whitewood Encryption Systems), Jane E. Nordholt and Richard Hughes (retired Los Alamos employees); Robert Van Rooyen (Summit Scientific Inc.), and Alex Rosiewicz (A2E Partners, Inc.).

The Laboratory Directed Research and Development (LDRD) program initially sponsored the Los Alamos work, which the DoD’s Defense Advanced Research Projects Agency (DARPA) later funded. The Department of Homeland Security’s Transition to Practice program within the department’s Science and Technology directorate helped bring the technology to market. The work supports the Laboratory’s Global Security mission area and Nuclear and Particle Futures science pillar through the development of cybersecurity methods. Technical contact: Raymond Newell

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Research Library

First content drift measurement for references to web pages made in scientific articles

As publishing becomes more web-based, understanding the impact that the web’s dynamic and ephemeral nature has on the scientific record becomes more important. Scholarly articles contain URI references to “web at large” resources including project web sites, scholarly wikis, ontologies, online debates, presentations, blogs, and videos. Authors reference these resources to provide essential context for their research. A reader who visits a web at large resource by following a URI reference in an article some time after its publication could believe that the resource’s content is representative of what the author originally referenced. However, due to the dynamic nature of the web, that may not be the case. Los Alamos researchers and collaborators reused a dataset from a previous study to investigate to what extent the textual content of web at large resources referenced in a vast collection of papers in scientific journals changes. The Public Library of Science One (PLOS ONE) published their findings.

The team discovered that web dynamics yield two different phenomena that have a detrimental impact. 1) Link Rot refers to the disappearance of the referenced web page altogether. 2) In Content Drift, a reference points to a web page that has changed since the original paper was published and no longer represents the content that existed when the author referenced it. These two phenomena combined are referred to as Reference Rot.

Prior studies, including one conducted in 2014 by the same team from Los Alamos, largely focused on quantifying Link Rot. This new paper is the first to scientifically quantify Content Drift for references to web pages made in scientific articles. It does so by first selecting representative snapshots of referenced pages from web archives around the world, and then textually comparing these snapshots with their counterparts on the live web.

Content Drift and Link Rot for links to web pages found in the arXiv corpus.

Content Drift and Link Rot for links to web pages found in the arXiv corpus. Link Rot is represented in black, Content Drift in blue. The darker the blue of a bar, the more the content originally referenced in a respective article publication year is textually different from the current content on the live Web. “Similar = 100” indicates that the live web content is still the same as when it was referenced. Both Content Drift and Link Rot became worse for older references. This trend is also present in other Science, Technology and Medicine corpora that were studied.

The Los Alamos authors revisited the dataset from their 2014 PLOS ONE paper to quantify the extent of Content Drift. They found that, overall, 75% of references to web pages are affected and that the problem gets progressively worse the older the referencing article is. Moreover, archived snapshots that are representative of what the author referenced are only available for 30% of references. These numbers provide a unique insight in the impact that web dynamics have on the integrity of the web-based scholarly record. The authors also studied approaches to ameliorate the Reference Rot problem, and advocated the use of Robust Links.

Reference: “Scholarly Context Adrift: Three out of Four URI References Lead to Changed Content,” Public Library of Science One (PLOS ONE) 11, (12) e0167475 (2016); doi: 10.1371/journal.pone.0167475. Authors: Shawn M. Jones, Herbert Van de Sompel, Harihar Shankar, and Martin Klein (Research Library, SRO-RL); Richard Tobin and Claire Grover (University of Edinburgh).

A grant from the Andrew W. Mellon Foundation funded the Hiberlink project, a collaborative effort between the LANL Research Library and the University of Edinburgh. The research supports the Lab’s mission areas and the Information, Science and Technology science pillar. Technical contact: Herbert Van de Sompel

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