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DOE OSTI2017

Theoretical Research at the High Energy Frontier: Cosmology and Beyond

The forefront of particle physics has focused on possible physics beyond the standard model which might help explain its peculiarities, including the nature of the spectrum of masses of elementary particles, the peculiar hierarchy between the Planck scale and the electroweak scale, and the possible manner in which the standard model might be embedded in a quantum theory which incorporates gravity. Over the past several decades it has become clear that several of the key out-standing problems associated with our understanding of fundamental interactions are inextricably tied to questions that are also of current interest in cosmology and astrophysics. At the same time, remarkable new data is being gathered that will allow empirical testing of theoretical ideas that have been around for a generation, from the discovery of the Higgs at the LHC to the possible detection of gravitational waves from Inflation at the GUT scale. The questions of the origin of mass, and possible grand unification are both tied to the possible existence of phase transitions in the early universe. Neutrino masses, as probed from astrophysical sources, may play a key role in elucidating the physics associated with the generation of baryon number. It is also possible that new physics at the electroweak scale may play a role in the nature of primordial cosmological magnetic fields. Low Energy Supersymmetry as a solution to the hierarchy problem can predict, besides events detectable at the LHC, stable weakly interacting particles that might make up the dark matter of the universe. The possible existence of large extra dimensions might also impact upon the hierarchy problem, but these could also dramatically affect our picture of the evolution of the Universe both at early times, and possibly on large scales. Inflation may depend upon new physics at the GUT scale, but its detection may now be imminent with the possible detection of a gravitational wave signature in the Cosmic Microwave Background Radiation. Undoubtedly the most significant outstanding problem in high-energy physics is also a problem in cosmology, and indeed originated not from accelerators but from astrophysical observations: What is the origin and nature of the dark energy that appears to dominate the Universe? An understanding of quantum gravity, and perhaps a new understanding of quantum mechanics or quantum field theory may be required to fully address this problem. At the moment, the physics of black holes may provide the best opportunity to explore these issues, while the discovery of the Higgs suggests several new possible connections to physics that might be relevant for dark energy. Finally, pending confirmation of a gravitational wave signal from inflation, to date the only direct evidence for fundamental particle physics beyond the standard model comes, at least in part, from astrophysical neutrino observations. A remarkable convergence of theory, observation and experiment has been taking place that is allowing great strides to be made in our knowledge of the parameters that describe the universe, if not the origin of these parameters. Given the new discoveries now being made, and the incredible capabilities of future instruments, it is an exciting time to make progress in our fundamental understanding the origin and evolution of the Universe and the fundamental forces that guide that evolution. As a result, it is natural that our DOE theory research program at Arizona State University focuses in large part on the connections between particle physics and cosmology and astrophysics in order to improve our understanding of fundamental physics. Our areas of research cover all of the areas described above. Our group now consists of four faculty PI’s and their postdocs and students, complemented by long term visitor Frank Wilczek, and physics faculty colleagues Cecilia Lunardini, Richard Lebed, and Andrei Belitsky, whose interests overlap in areas ranging from particle theory and phenomenology to neutrino astrophysics. In addition, we interact with astronomers, and experimentalists in both Physics and the School of Earth and Space Exploration. In addition, Krauss and Parikh are associated, respectively, with the ASU Origins Project and the ASU Beyond Center. Both of these groups have helped us leverage DOE funds by supporting workshops associated with our activities from time to time. To continue the active program we have built up here, we are asking for support for 3 graduate students, and 3 postdocs (note that the PI will forego summer salary support in order to support one additional postdoc beyond the request in our last proposal for 2 postdocs). We have been fortunate to build a vibrant group based in part on University startup support for our program. Now that that support is coming to a close for most of our group, we are hoping that the exciting program we have created motivates continued DOE support at a level that, while not as great as the level we enjoyed with startup support, will nevertheless allow us to maintain our momentum.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

(Project 14-6770) An Investigation to Establish Multiphysical Property Dataset of Nuclear Materials Based on in-situ Observations and Measurements

In-core nuclear materials including fuel pins and cladding materials fail due to issues including corrosion, mechanical wear, and pellet cladding interaction. In most such scenario microstructure dependent and corrosioninduced chemistry dependent property changes significantly affect performance of cladding, pellet, and housing. Emphasis of this work was on replace conventional pellet-cladding material models with a new straingradient viscoplasticity model that is informed by transmission electron microscopy (TEM) based measurements and by nanomechanical Raman spectroscopy (NMRS) based measurements. The TEM measurements are quantitative in nature and therefore reveal stress-strain relations with simultaneous insights into mechanisms of deformation at nanoscale. The NMRS measurements reveal the similar information at mesoscale along with additional information on relating local microstructural stresses with applied stresses. The resulting information is used to fit constants in the strain gradient viscoplasticity model as well as to validate one. During TEM measurements, a micro-electro-mechanical system based setup was developed with mechanical actuation, sensing, heating, and electrical loading. Contrary to post-mortem analysis or qualitative visualization, this setup combines direct visualization of the mechanisms behind deformation with measurement of stress, strain, thermal and electrical properties. The unique research philosophy of visualizing the microstructure at high resolution while measuring the properties led to fundamental understanding in grain size and temperature effects on measured mechanical properties such as fracture toughness. A key contribution is the role of mechanical loading boundary conditions to deconvolute the insitu TEM based nanoscale and NMRS based mesoscale data to bulk behavior. First the literature based pellet cladding mechanical interaction model based on the work of Retel’s and Williamson’s in literature work to predict tempurature and stress distribution in cladding and pellet at normal operating condition was analyzed. Later the data was fitted to find constants for a viscoplastic strain gradient model. The developed model still needs to be refined and calibrated using various experimental results. That remains the focus of future work. Overall, a major thrust of the work was therefore on active control of the microstructure (grain size, defect density and types) exploiting the multi-physics coupling in materials. In particular, using experiments the synergy of current density, mechanical stress and temperature were studied to annihilate defects and recrystallize grains. The developed model is being examined for implementation in BISON. Multiple invited talks, international journal publications, and conference publications were performed by students supported on this work. Another output is support multiple PhD and masters thesis students who will be an important asset for future basic nuclear research. Future Work Recommendations: A nuclear reactor operates under significant variations of thermal loads due to energy cycling and mechanical loads due to constraint effects. Significant thermal and chemical diffusion takes place at the pallet-cladding level. While the proposed work established new experimental approach and new dataset for Zircaloy-4, the irradiation level was in the range of 1-2 dpa. Samples with higher dpa need to be examined. Therefore, a continual of support of the performed work is essential. Currently, these are the only experiments that can measure the produced data. The work also needs to be extended to different fuel types and cladding types such as SiC and FeCrAl based claddings. A combination of datasets for these materials can then be used to analyze accurately predict behavior of critical pellet cladding systems in accident scenario with high heat flux and high thermal loads. This is a BIG unknown as if now.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

High-efficiency Thin-film Fe 2 SiS 4 and Fe 2 GeS 4 -based Solar Cells Prepared from Low-Cost Solution Precursors. Final Report

The project aimed to provide solar energy education to students from underrepresented groups and to develop a novel, nano-scale approach, in utilizing Fe 2 SiS 4 and Fe 2 GeS 4 materials as precursors to the absorber layer in photovoltaic thin-film devices. The objectives of the project were as follows: 1. Develop and implement one solar-related course at Delaware State University and train two graduate students in solar research. 2. Fabricate and characterize high-efficiency (larger than 7%) Fe 2 SiS 4 and Fe 2 GeS 4 -based solar devices. The project has been successful in both the educational components, implementing the solar course at DSU as well as in developing multiple routes to prepare the Fe 2 GeS 4 with high purity and in large quantities. The project did not meet the efficiency objective, however, a functional solar device was demonstrated.

14 SOLAR ENERGY↗
DOE OSTI2017

Holography, Gravity and Condensed Matter

Over the five years of funding from this grant, I produced 26 publications. These include a book-long monograph on "Holographic Quantum Matter" that is currently in press with MIT press. The remainder were mostly published in Physical Review Letters, the Journal of High Energy Physics, Nature Physics, Classical and Quantum Gravity and Physical Review B. Over this period, the field of holography applied to condensed matter physics developed from a promising theoretical approach to a mature conceptual and practical edifice, whose ideas were realized in experiments. My own work played a central role in this development. In particular, in the final year of this grant, I co-authored two experimental papers in which ideas that I had developed in earlier years were shown to usefully describe transport in strongly correlated materials — these papers were published in Science and in the Proceedings of the National Academy of Sciences (obviously my contribution to these papers was theoretical). My theoretical work in this period developed several new directions of research that have proven to be influential. These include (i) The construction of highly inhomogeneous black hole event horizons, realizing disordered fixed points and describing new regimes of classical gravity, (ii) The conjecture of a bound on diffusivities that could underpin transport in strongly interacting media — an idea which may be proven in the near future and has turned out to be intimately connected to studies of quantum chaos in black holes and strongly correlated media, (iii) The characterization of new forms of hydrodynamic transport, e.g. with phase-disordered order parameters. These studies pertain to key open questions in our understanding of how non-quasiparticle, intrinsically strongly interacting systems can behave. In addition to the interface between holography and strongly interacting condensed matter systems, I made several advances on understanding the role of entanglement in quantum gravity. These included the first computation of holographic entanglement beyond the bulk classical limit as well understanding short distance entanglement in the emergent spacetime of the c=1 matrix quantum mechanics. The objective here is ultimately to understanding how a priori non-local degrees of freedom can re-arrange themselves quantum mechanically to support emergent local dynamics. Much of work funded by this grant involved collaboration with postdocs and graduate students, several of which were directly funded by the grant. These students have now successfully graduated to postdoctoral positions and in one case to high tech industry. The ideas developed in this work have directly fed into my current research in which I am aiming to prove fundamental bounds on entropy production and transport from quantum mechanics and statistical physics. As often, as with much of my previous work, black hole physics can be an inspiration for extreme dynamics such as fundamental bounds, but ultimately one hopes to prove them using more general tools of quantum field theory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

University of Texas Safeguards by Design Problem Statement

This document describes the problem statement that students at the University of Texas will use for their senior level capstone design class. The purpose of this project is to introduce students to Safeguards by Design concepts as part of their capstone design course at the culmination of their degree program. This work is supported by Los Alamos National Laboratory with FY17 and FY18 programmatic funding from the U. S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA), through the Office of Defense Nuclear Nonproliferation (DNN), Office of International Nuclear Safeguards (INS), Next Generation Safeguards Initiative (NGSI), Human Resource Development Program, Safeguards by Design Project.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2018

Final Report: N-Acylethanolamine metabolism and the acquisition of photoautotrophy during seedling establishment

Research in our labs, supported since 2005 by Basic Energy Sciences, has led to the discovery of a new lipid mediator pathway that influences phytohormone-mediated regulation of plant growth and development—the so-called N-acylethanolamine (NAE) regulatory pathway. This pathway in plants shares conserved metabolic machinery with the endocannabinoid signaling system of vertebrates that regulates a multitude of physiological and behavioral processes in mammals, suggesting that the metabolism of NAEs is an important regulatory feature of eukaryotic biology. Current evidence in plants points to interactions between NAE metabolism, abscisic acid (ABA) signaling and light signaling to modulate seedling establishment and the acquisition of photoautotrophic growth. The proposed research fits well within the mission of Photosynthetic Systems and Physical Biosciences which seek “to understand the processes by which plants, algae and non-medical microbes capture, convert and/or store energy”. The fundamental regulatory processes that govern seedling establishment directly influence the assembly of photosynthetic energy conversion systems in essentially all higher plants. Our main hypothesis is that seedlings coordinate the metabolic depletion of NAEs during seedling establishment through a complex interaction of hydrolysis (by fatty acid amide hydrolase, FAAH) and oxidation (by lipoxygenases, LOX) and that newly-reported oxylipin metabolites of polyunsaturated NAEs help to coordinate seedling development and acquisition of photoautotrophy in response to appropriate environmental cues. Evidence suggests that ethanolmide oxylipins derived from NAEs can reversibly accumulate in seedlings and adjust/arrest seedling establishment and chloroplast development in conjunction with ABA signaling and light-signaling pathways. Our results provide important new information linking the production of small molecule lipid mediators in seedlings to the coordinated development of photoautorophy. While relevant to how plants capture, convert and store energy, this work also extends to the general understanding of acylethanolamides and their bioactivity in eukaryotic organisms. In addition, analytical mass spectrometry methodology developed in this work also helped to demonstrate the identification, quantification and spatial localization of NAEs and other lipids in various plant and animal tissues. Cumulative scholarly output includes 45 publications, 2 U.S. Patents, and 24 invited research seminars. This research funding also supported the training of 2 master’s students, 4 Ph.D. students and 3 postdoctoral scholars, enhancing the human infrastructure of the U.S. science enterprise.

09 BIOMASS FUELS↗
DOE OSTI2017

Support of A Summer School Workshop and Workshop Focused on Theory and Applications of Time-Dependent Density Functional Theory

The first US-based summer school and workshop on Time-Dependent Density Functional Theory (TDDFT) was held July 11-21, 2017 in Telluride, CO. This grant provided funding to enable 33 students to attend the school, specifically with lodging and registration fee reductions. TDDFT is increasingly used in computational molecular and materials science to calculate electronic-excitation spectra and dynamics in a wide variety of applications, including photocatalysis, photo-controlled bond dissociation, and light-induced charge transfer. Software development in this community targets multiple software packages, many of which are open source, such as octopus, NWchem and Qb@ll, which are the ones our school focused on. The goal of this first iteration was to create a home for a national community of scholars, including users and developers, with a deep understanding of TDDFT, its capabilities, limitations, and high-performance computing context. We used this opportunity to explore interest in such an event in the future and based on overwhelmingly positive feedback from students and teachers, we intend to hold a similar school+workshop every two years in the US, in order to maintain the high level of interest that we witnessed and the enthusiasm amongst participants.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Project Final Report: The Institute for Sustained Performance, Energy, and Resilience (SUPER)

This project concentrated on various aspects of creating and applying tool infrastructure to make it easier to effectively use large-scale parallel computers. This project was collaborative with Argonne National Laboratory, Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, U.C. San Diego, University of Maryland, University of North Carolina, University of Oregon, University Southern California, University of Tennessee, and University of Utah. The research conducted during this project at the University of Maryland is summarized in this report. The complete details of the work are available in the publications listed at the end of the report. Many of the concepts created during this project have been incorporated into tools and made available as freely downloadable software (www.dyninst.org/harmony). It also supported the studies of six graduate students, one undergraduate student, and two post-docs. The funding also provided summer support for the PI and part of the salary of a research staff member.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

GATE: Energy Efficient Vehicles for Sustainable Mobility-Project TI022- FinalReport

Unique opportunity for industry to engage in original, highly leveraged precompetitive research in automotive and transportation systems, with focus on advanced propulsion systems; fuel economy; vehicle safety, connectivity and autonomy; and advanced driver assistance systems Additional benefits: prepare graduate students for future careers in automotive industry, reaching undergraduate students through capstone design and other project activities, focused recruitment events

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

The Flotation Chemistry of Nonsulfide Minerals

Particulate separations are of considerable significance in many areas of technology ranging from pharmaceutics and microelectronics, to mining and construction materials industries. In addition, particulate separation technology is of critical importance in the environmental area, for example, the development of advanced water treatment processes for the 21st century will rely on more efficient particulate separation techniques. In this regard it is most appropriate that the Separations Program of the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, of DOE supports basic science research in the area of particulate separations. One such particulate separation process of special importance is froth flotation, a physico-chemical process that is used to separate particles in an aqueous suspension via differences in hydrophobicity as established by the interaction of various reagents at the solid/water, solid/gas and water/gas interfaces. Surfactants, called collectors, are added to a suspension to selectively adsorb at the surface of specific particles, rendering these particles hydrophobic. Regulators are employed to promote collector adsorption at the desired surfaces, while preventing such reactions at other surfaces. When air is dispersed into the suspension, the bubbles generated attach to the hydrophobic particles. The resulting bubble/particle aggregates float to the suspension surface and are collected in a froth phase as a concentrate. The remaining hydrophilic particles are retained in suspension and discharged as a tailings product. Clearly, particulate separation by froth flotation is an outstanding example of applied surface chemistry, and is used in the food, petroleum, pulp/paper, and mineral industries. The use of flotation technology is perhaps most significant in the mineral industry where, in the U. S. alone, over 500,000 tons/day of nonsulfide minerals are processed. The estimated value of all nonfuel mineral materials processed in the United States during 2015 totaled $630 billion. It is evident that particle separation by flotation is an important process that is used in many of the mineral industries. Understanding of the interfacial chemistry for the development of improved flotation separations is required for more effective production and utilization of our mineral resources, especially the critical minerals as identified in the 2017 USGS report, “Critical Mineral Resources of the United States – Economic and Environmental Geology and Prospects for Future Supply.” In this regard, a research program has been in progress with DOE support from Grant DE-FGO2-93ER14315 to study the fundamental interfacial chemistry features in nonsulfide mineral flotation systems in order to increase our understanding and provide for improved separation efficiencies and energy economy in the processing of our mineral resources. Significant contributions have been made to the flotation chemistry of flotation separations in many areas, including, salt minerals; collector adsorption; wetting, surface forces, bubble attachment; interfacial water structure; phyllosilicate minerals, and critical mineral resources such as rare earth minerals and lithium resources. The research results summarized herein have resulted in more than 225 publications, the education of 28 PhD graduate students, and impressive recognition with university, national, and international awards. For example, among many other awards, Distinguished Professor Jan Miller, PI, was elected to be a member of the National Academy of Engineering (1993) and the National Academy of Inventors (2014). In 2015 he received the University of Utah’s most prestigious award presented annually to a faculty member, the Rosenblatt Prize for Excellence. Research Professor Xuming Wang was selected by SME to be a Henry Krumb Lecturer (2013-2014), and many of the student researchers involved in the program received national awards from AIME, ICE, IPMI, SME, and TMS. It is evident that the flotation separation research program has been quite successful. Unfortunately, the flotation chemistry research for mineral particle separation has been terminated even though the renewal proposal received excellent reviews with recommended funding. The need for continued support of minerals separation research is of critical importance as recognized by 1) the recent 2017 USGS report, “Critical Mineral Resources of the United States – Economic and Environmental Geology and Prospects for Future Supply,” and by 2) the 20 December 2017 executive order from President Trump to increase the discovery, production, and domestic refining of critical minerals. In view of our research accomplishments, the excellent reviews of the renewal proposal, and the expressed need for attention to the production of critical minerals, termination of “The Flotation Chemistry of Nonsulfide Minerals” research program by DOE is not appropriate, and continued support should be reconsidered.

58 GEOSCIENCES↗
DOE OSTI2018

Molecular Dynamics-based Simulations of Bulk/Interfacial Structures and Diffusion Behaviors in Nuclear Waste Glasses

This NEUP Project aimed to generate accurate atomic structural models of nuclear waste glasses by using large-scale molecular dynamics-based computer simulations and to use these models to investigate self-diffusion behaviors, interfacial structures, and hydrated gel structures formed during dissolution of these glasses. The goal was to obtain realistic and accurate short and medium range structures of these complex oxide glasses, to provide a mechanistic understanding of the dissolution behaviors, and to generate reliable information with predictive power in designing nuclear waste glasses for long-term geological storage. Looking back of the research accomplishments of this project, most of the scientific goals initially proposed have been achieved through intensive research in the three and a half year period of the project. This project has also generated a wealth of scientific data and vibrant discussions with various groups through collaborations within and outside of this project. Throughout the project one book chapter and 14 peer reviewed journal publications have been generated (including one under review) and 16 presentations (including 8 invited talks) have been made to disseminate the results of this project in national and international conference. Furthermore, this project has trained several outstanding graduate students and young researchers for future workforce in nuclear related field, especially on nuclear waste immobilization. One postdoc and four PhD students have been fully or partially supported through the project with intensive training in the field material science and engineering with expertise on glass science and nuclear waste disposal

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Combining Experiments and Simulations of Extraction Kinetics and Thermodynamics in Advanced Separation Processes for Used Nuclear Fuel

This 3-year project was a collaboration between University of California Irvine (UC Irvine), Pacific Northwest National Laboratory (PNNL), Idaho National Laboratory (INL), Argonne National Laboratory (ANL) and with an international collaborator at ForschungZentrum Jülich (FZJ). The project was led from UC Irvine under the direction of Profs. Mikael Nilsson and Hung Nguyen. The leads at PNNL, INL, ANL and FZJ were Dr. Liem Dang, Dr. Peter Zalupski, Dr. Nathaniel Hoyt and Dr. Giuseppe Modolo, respectively. Involved in this project at UC Irvine were three full time PhD graduate students, Tro Babikian, Ted Yoo, and Quynh Vo, and one MS student, Alba Font Bosch. The overall objective of this project was to study how the kinetics and thermodynamics of metal ion extraction can be described by molecular dynamic (MD) simulations and how the simulations can be validated by experimental data. Furthermore, the project includes the applied separation by testing the extraction systems in a single stage annular centrifugal contactor and coupling the experimental data with computational fluid dynamic (CFD) simulations. Specific objectives of the proposed research were: Study and establish a rigorous connection between MD simulations based on polarizable force fields and extraction thermodynamic and kinetic data. Compare and validate CFD simulations of extraction processes for An/Ln separation using different sizes (and types) of annular centrifugal contactors. Provide a theoretical/simulation and experimental base for scale-up of batch-wise extraction to continuous contactors. We approached objective 1 and 2 in parallel. For objective 1 we started by studying a well established extraction system with a relatively simple extraction mechanism, namely tributyl phosphate. What we found was that well optimized simulations can inform experiments and new information on TBP behavior was presented in this project, as well be discussed below. The second objective proved a larger challenge and most of the efforts were devoted to experimental studies.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

Symposium NM09: Novel Approaches and Material Platforms for Plasmonics and Metamaterials

The goal of this symposium was to present through a series of invited lectures from world-leading experts in the field, an overview of the current state-of-the-art in nanophotonics over a broad swath of topics, ranging from metal-based plasmonics to dielectric species. It was focused on investigations into novel resonator designs and into alternative materials. Over the 10 years it has been held, this symposium has provided an excellent education forum to participating students and postdocs through the direct interaction with world-renowned researchers, the opportunity to present their research results in both poster and oral form, the full-day tutorial session before the conference, and in listening to the results of other research groups. DOE funding provided need-based travel support to students and invited speakers who had financial difficulties in participating in the MRS meeting. The organizers made every effort to publicize the available support and were strongly committed to encourage participation from under-represented groups including women and minorities. The organizers are grateful to DOE for its support.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Organic Speciation and Interactions in ALSEP. One Step Partitioning Process of MinorActinides, Lanthanides, and Fission Products

Research conducted in this project focused on speciation characterization of the ALSEP extraction system (similar to the TALSPEAK-like application) which addresses recovery of minor actinides and lanthanides from PUREX raffinate. The ALSEP (Actinide-Lanthanide Separation) system proposes a trivalent minor actinide/lanthanide group extraction followed by a selective actinide strip to effectively partition minor actinides, lanthanides, and other fission products. The group extraction is achieved by a mixed organic solvent, combining acidic and neutral extracting ligands. The objective of this work is investigation the interactions of the acidic and neutral ligands with each other in the extraction organic solvent and with desired metals. Four combinations of a cation-exchange ligand (either HDEHP or HEH[EHP]) and a neutral solvating ligand (either TODGA or T2EHDGA) in n-dodecane were studied. Interligand dimers in these combinations were investigated with NMR and FTIR, the strongest interaction was observed for HDEHP+TODGA and weakest for T2EHDGA+HEH[EHP]. Complexes of the trivalent Am and lanthanides Nd, Eu, Ho, Pr in these binary ligand mixtures were probed with spectroscopic (UV–vis, time-resolved fluorescence, XAFS and SAXS-spectroscopies) and extraction (Job’s plot, slope analysis) methods; co-extracted water and nitric acid were analyzed by titration methods. Comparison of the collected spectra showed significant shifting for both DGA ligands with HDEHP, while both combinations of HEH[EHP]+DGA displayed much smaller spectral changes. Data were modeled with HypSpec program, and stability constants for extracted complexes were calculated. Aggregation in these systems were studied by SAXS (small-angle X-ray scattering) spectroscopy and interfacial tension, size of aggregates were measured. Two PhD students graduated (2017, 2018) and one student continues her PhD study.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

Advanced Models for Nondestructive Evaluation of Aging Nuclear Power Plant Cables

Background: Nuclear power plant (NPP) cables must function correctly for proper power supply and control of the nuclear reactor. This is especially important for public and environmental safety at critical times such as during reactor shut-down following loss of coolant. Over extended periods of service, the cable insulation and jacket polymer materials suffer from degradation due to exposure to environmental stressors such as heat and ionizing radiation. The focus of this project has been the development of detailed descriptions of the way in which insulation polymers degrade, from a materials science perspective, and the development of new electrical techniques to monitor cable polymer condition nondestructively. Objectives: The objectives of this project have been to i) perform detailed characterization experiments upon cable insulation polymers that have experienced thermal and radiation exposure mimicking that received during NPP operation, including the exploration of novel cable nondestructive evaluation methods; capacitive, THz and infrared methods; ii) identify the most sensitive indicators of aging in these materials, and iii) develop advanced, validated models describing microstructural and chemical changes that are observed in cable insulation polymers due to thermal and radiation exposure. Methods: Accelerated aging was performed on the two most common United States NPP cable insulation polymers (cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR)) under various conditions of elevated temperature and gamma radiation dose. Aging mechanisms were elucidated through extensive thermal, mechanical and microscopic characterization of the aged samples, and materials modeling. Dielectric and IR spectra were measured on pristine and aged samples. Data was analyzed statistically, via multiple linear regression, partial least squares and probabilistic neural network approaches. Impact: Extant cable monitoring techniques do not deal successfully with all polymer types. This research has laid a foundation upon which new electrical nondestructive test methods for cable polymer condition monitoring may be developed, hence launching the development of new test methods for cable insulation monitoring based on measuring electrical rather than mechanical parameters. Collaboration: This project has benefitted from collaboration between experts in materials science and engineering, materials modeling, electrical engineering, and nondestructive evaluation. The majority of the characterization measurements were carried out at Iowa State University. Materials modeling was carried out primarily at Washington State University. Irradiation of samples took place at Pacific Northwest National Laboratory (PNNL), where a student intern from Iowa State was hosted for one summer, setting up the aging experiments. A research student from the University of Bologna, Italy, joined the project for their thesis research at Iowa State University with samples provided by PNNL. The project benefitted from regular involvement of senior engineers in US-based industry partners. Project investigators presented findings at various national and international conferences and workshops.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2018

Asparagine synthetase gene regulatory network and plant nitrogen metabolism

This DOE project concerns the molecular mechanisms by which plants coordinate carbon (C) and nitrogen (N) metabolism. Specifically, it focuses on a histone methyltransferase protein that targets C/N-metabolism genes for chromatin modifications. How the dynamic changes of chromatin regulate energy metabolism in response to developmental and environmental cues is a new area of study. We have filled this knowledge-gap with our studies of SDG8, a histone methyltransferase, that targets light, C and N metabolism genes. We aimed to understand how plants allocate C resources to assimilate inorganic N onto C-skeletons -- the most energy-intensive pathway in plants – in order to balance energy production and consumption in a changing environment. In order to achieve more C-efficient N-storage under low energy conditions, plants convert assimilated N from “reactive” Gln (C5:N2) into “inert” Asn (C4:N2) through the enzyme ASN1. To identify regulatory factors in this pathway, we used the ASN1 promoter in a genetic selection and discovered SDG8, a histone methyltransferase. We discovered that histone modification by SDG8 coordinates the expression of genes involved in energy generation (light-harvesting and C fixation) with energy consumption (N assimilation and sulfur metabolism). We used this opportunity to explore how histone modifications control energy metabolism genome-wide. Our aims focus on various levels of the regulation of energy related genes at the level of: 1) Chromatin; 2) Transcription; and 3) Metabolites of the C/N regulatory network. Specifically, we asked: 1) How does histone methylation regulate energy metabolism during the N response? 2) How does histone methylation control transcription of the energy metabolism genes? And 3) how does the histone methyltransferase SDG8 and other TF regulators affect C/N metabolism and N use efficiency? Our study indicates that N supply triggers genome-wide changes in chromatin modification via the histone methyltransferase SDG8 which impacts on gene expression, RNA processing, chlorophyll synthesis, N uptake and metabolism. Our study thus revealed a previously overlooked layer of chromatin regulation during nutrient signaling. In broad terms, our study provides a framework to understand how chromatin modifications influence responses to environmental changes and provides unique opportunities for breeding and engineering resilient crops with better performance in the current climate model. Accomplishments AIM 1 CHROMATIN: Role of histone methylation in the ASN1 energy metabolism network. This aim focuses on understanding the role of chromatin modification in response to the environment. We studied the targeting mechanism of histone methylation by SDG8, in particular the role of the CW domain in reading histone methylation status. We also began to study the effect of nitrogen-treatment on genome-wide chromatin modifications in WT and sdg8 mutant plants. AIM 2 TRANSCRIPTION: Transcription control of the ASN1 energy metabolism network. This aim investigated whether SDG8 and the histone modification it mediates affects mRNA processing. We performed genome-wide profiling that uncovered that histone methylation by SDG8 affects the co-transcriptional RNA processing of downstream genes involved in energy and photosynthesis. AIM 3 METABOLISM: A gene regulatory network controlling energy, C/N metabolism and N use efficiency. In Aim 3A, we showed that SDG8 affects the chromatin modification and expression of a transcription factor, CCT, which in turn affects the regulation of carbon responsive genes. In Aim 3B we showed that C and N metabolism is perturbed in the sdg8 mutant through differences in the chlorophyll content, free amino acids, and N uptake. Project activities In Aim 1, we uncovered that the histone methyltransferase SDG8 affects chromatin modification in response to N treatments. The N treatments causes changes in the H3K36me3 distribution off ~200 genes in WT plants, while the N-triggered changes in H3K36me3 of these genes is abrogated in the sdg8-5 mutant. The functional annotation of these 200 genes shows significant enrichment of N-related pathways. Overall, our study suggests that SDG8 mediates chromatin-level adaption of functionally relevant genes in response to changes in N. In Aim 2, we tested if SDG8 plays a role in transcriptional elongation and/or RNA processing. We detected more N-triggered isoform shifting events in the sdg8-5 mutant than in WT, which provides supports for SDG8 being required for proper RNA processing in response to N signaling. In Aim 3, we identified the gene network controlled by a CCT transcription factor under the epigenetic control of SDG8. Isoform abundance of the CCT protein is regulated by SDG8, which leads to an altered response of energy related genes to N level changes. Using physiological, metabolic and genetic approaches, we found that responses to N, including chlorophyll accumulation, N uptake and free amino acids, are altered in sdg8 mutants. Finally, this project provided training to a high school student who performed experiments on the complex interaction of photosynthesis and N availability. The student was named a semi-finalist in both the Regeneron and Siemens National Science competitions for her work.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Sun Grant/DOE Regional Feedstock Partnership: Final Technical Report

The U.S. Department of Energy (DOE) and the Sun Grant Initiative initiated the Regional Feedstock Partnership (referred to as the Partnership) in 2007 primarily to address information gaps associated with the likelihood for realization of the sustainable and reliable production of a billion-tons of biomass annually to support the U.S. bioenergy industry by the year 2030. Publication of The Technical Feasibility of a Billion-Ton Annual Supply (Perlack et al., 2005) in 2005, with its associated yield assumptions, led to the realization that the yield goals and assumptions utilized in that analysis required careful validation. To achieve the overall goal of validating key yield assumptions, the following objectives were developed: 1. Establishment of replicated field trials across regions to determine the impact of crop residue removal (primarily corn and small grains) on future grain yields and soil health. 2. Establishment of replicated field trials of some of the most promising dedicated energy crops (herbaceous annuals and perennials, as well as woody perennials) to demonstrate the potential performance of these feedstocks across the U.S. 3. Assessment of feedstock resources to be used to estimate a sustainable national supply potential. Teams composed of representatives from Land Grant Universities, USDA ARS, DOE National Laboratories, industry, and other federal agencies were identified and assembled to address each of these objectives. For Objective 1, members of the USDA ARS’ Resilient Economic Agricultural Practices (REAP) team combined with university personnel to leverage on-going work and established new trials to determine sustainable corn residue removal rates. In addition, universities across the continental U.S. conducted surveys of published past research to define parameters for the use of cereal grain residue (primarily wheat) as a biomass feedstock. For Objective 2, and based on input from DOE, USDA, Land Grant university scientists, and others, several herbaceous and woody energy crop species were selected for new or further evaluation across wide geographic areas as cellulosic feedstock sources. Species teams were organized to assess the yield potential of candidate herbaceous feedstocks including sorghum, energycane, Miscanthus x giganteus (hereafter referred to as miscanthus), switchgrass, and mixed perennial species (primarily grasses and some legumes) on Conservation Reserve Program (CRP) land. Woody species will be critical components of the bioenergy sector; therefore, species teams were also organized for shrub willow and hybrid poplar (Populus spp.). Field trials of each species were utilized to determine yield potential across the U.S. For Objective 3, a GIS resource team was organized with representatives from each of the five Sun Grant regions. While some regional assessments were made, the multi-institutional team decided that the group from Oregon State University would utilize their PRISM ELM model to estimate national yield potential of the various species evaluated. The following are key outcomes and impacts • The Partnership demonstrated the production potential of diverse herbaceous and woody feedstocks across much of the U.S. for 5-7 consecutive growing seasons. Long-term studies such as this are not commonly possible due to limitations in funding cycles. • Long-term field trials were valuable in demonstrating the importance of agronomic management practices and genetic resources to yield of sorghum, switchgrass, miscanthus, energycane, CRP mixed perennial grasses, poplar, and willow. • National yield potential maps were developed for all species evaluated in the Partnership. • Sustainable corn stover removal rates were quantified for use by producers, harvesters, and commercial lignocellulosic biorefineries. • Data from the Partnership field trials not only validated initial Billion Ton estimates, but were instrumental in developing both the Billion Ton Update in 2011, and especially the 2016 Billion Ton Report. • The Partnership provided the opportunity to assemble and conserve a poplar germplasm collection that contains more than 20,000 clones for use in breeding programs. New clones resulting from crosses made using this germplasm collection have resulted in significantly improved cultivars that could be scaled up and deployed. • Further validation of improved yields of new varieties/cultivars of biomass sorghum, energycane, hybrid poplars, and shrub willows was produced by the Partnership. • The Partnership demonstrated the potential of energycane in northern parts of the southeastern U.S., particularly in relation to sugarcane varieties. • For certain feedstocks (e.g., CRP mixed grasses, switchgrass, willow, and poplar), production economics were ascertained through Partnership field trials. • Biomass samples collected as part of the Partnership are also being used to populate Idaho National Laboratory’s Bioenergy Feedstock Library. • Because of the size and scope of the Partnership, workforce development was a key component and outcome. Numerous undergraduate students (25), graduate students (15 MS and 8 PhD), and postdoctoral researchers (7) were trained by Partnership participants. This will help to prepare individuals for careers in the emerging fields of plant breeding, biomass production, feedstock supply logistics, and biomass conversion processes. • More than 130 scientific publications have been authored by Partnership team members. Numerous other presentations, outreach publications, book chapters, and websites have also been developed to further the continued development of the bioeconomy.

09 BIOMASS FUELS↗
DOE OSTI2016

External Events P-204

Familiarize students with terminology and methodology to understand external event risk analysis. Enable students to understand external event analysis submittals from licensees History and progression of external events analysis. Overview of how external events are incorporated into SAPHIRE Level 1 model

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗