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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A machine learning photon detection algorithm for coherent x-ray ultrafast fluctuation analysis

X-ray free electron laser experiments have brought unique capabilities and opened new directions in research, such as creating new states of matter or directly measuring atomic motion. One such area is the ability to use finely spaced sets of coherent x-ray pulses to be compared after scattering from a dynamic system at different times. This enables the study of fluctuations in many-body quantum systems at the level of the ultrafast pulse durations, but this method has been limited to a select number of examples and required complex and advanced analytical tools. By applying a new methodology to this problem, we have made qualitative advances in three separate areas that will likely also find application to new fields. As compared to the “droplet-type” models, which typically are used to estimate the photon distributions on pixelated detectors to obtain the coherent x-ray speckle patterns, our algorithm achieves an order of magnitude speedup on CPU hardware and two orders of magnitude improvement on GPU hardware. We also find that it retains accuracy in low-contrast conditions, which is the typical regime for many experiments in structural dynamics. Finally, it can predict photon distributions in high average-intensity applications, a regime which up until now has not been accessible. Our artificial intelligence-assisted algorithm will enable a wider adoption of x-ray coherence spectroscopies, by both automating previously challenging analyses and enabling new experiments that were not otherwise feasible without the developments described in this work.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Nature of Decahydro-closo-decaborate Anion Reorientations in an Ordered Alkali-Metal Salt: Rb 2 B 10 H 10

The ordered monoclinic phase of the alkali-metal decahydro-closo-decaborate salt Rb 2 B 10 H 10 was found to be stable from about 250 K all the way up to an order-disorder phase transition temperature of ~762 K. The broad temperature range for this phase allowed for a detailed quasielastic neutron scattering (QENS) and nuclear magnetic resonance (NMR) study of the protypical B 10 H 10 2- anion reorientational dynamics. The QENS and NMR combined results are consistent with an anion reorientational mechanism comprised of two types of rotational jumps expected from the anion geometry and lattice structure, namely, more rapid 90 degree jumps around the anion C 4 symmetry axis (e.g., with correlation frequencies of ~2.6 x 10 10 s -1 at 530 K) combined with order of magnitude slower orthogonal 180 degree reorientational flips (e.g., ~3.1 x 10 9 s -1 at 530 K) resulting in an exchange of the apical H (and apical B) positions. Each latter flip requires a concomitant 45 degree twist around the C 4 symmetry axis to preserve the ordered Rb 2 B 10 H 10 monoclinic structural symmetry. This result is consistent with previous NMR data for ordered monoclinic Na 2 B 10 H 10 , which also pointed to two types of anion reorientational motions. The QENS-derived reorientational activation energies are 197(2) and 288(3) meV for the C 4 fourfold jumps and apical exchanges, respectively, between 400 and 680 K. Below this temperature range, NMR (and QENS) both indicate a shift to significantly larger reorientational barriers, for example, 485(8) meV for the apical exchanges. Finally, subambient diffraction measurements identify a subtle change in the Rb 2 B 10 H 10 structure from monoclinic to triclinic symmetry as the temperature is decreased from around 250 to 210 K.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A scalable transformer model for real-time decision making in neutron scattering experiments

The U.S. Department of Energy's (DOE's) neutron research facilities at Oak Ridge National Laboratory (ORNL), including the High Flux Isotope Reactor (HFIR) and the Spallation Neutron Source (SNS), are a state-of-the-art neutron scattering facility that allows researchers to study the structure and dynamics of materials at the atomic scale. At the SNS, neutrons are measured using the time-of-flight (TOF) technique as they move through a neutron beamline to interact with a sample. Large volumes of neutron scattering data are collected and recorded in neutron event mode. Optimal productivity of the TOF instrument is limited due to the lack of real-time data analysis tools. The large amount of data generated by the experiments can be challenging to process and analyze in real time, particularly for experiments that require rapid feedback and adjustment of experimental parameters. The regular computer/workstation cannot keep up with the experiment speed to provide real-time feedback to adjust experimental parameters, so connecting the supercomputers available to the neutron facility is necessary to achieve real-time data analysis and experiment steering. To address this challenge, we exploit the Frontier supercomputer at Oak Ridge Leadership Computing Facility (OLCF) to train a scalable temporal fusion transformer model for real-time decision making of TOF neutron scattering experimentation. Here, in this paper, we present the results using Frontier to provide the processing power needed to rapidly process and analyze large volumes of single-crystal diffraction data collected at TOPAZ, a neutron time-of-flight Laue single-crystal diffractometer at the SNS.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1965

Ground testing at MSFC

The large-scale field collection of acoustic data and their analysis are described in this review. The entire sound-field program has the purpose of solving complex problems of excessive noise propagation associated with the static test firing of large space-booster powerplants. The site of data collection has been Mississippi Test Facility (MTF), where far-field sound-propagation and correlated meteorological measurements were initiated in 1962. The statistical evaluation of sound-measurement data shows that the polar distribution of sound in the springtime (at MTF) is determined mainly by the temperature field of the atmosphere. Greater deformation of sound-intensity polar distribution occurs in the autumn as a result of the influence of the wind field. The data on sound attenuation as a function of distance from its source revealed attenuation in excess of the expected magnitude. The excess was mainly between 1 and 10 kilometers from the source, with maximum attenuation (17 to 18 decibels) near 6 kilometers. Excess sound attenuation was compared with calculated sound dispersion. For all sound frequencies in all seasons the deviation between reference and empirical attenuation values formed a bell-shaped distribution on a semilogarithmic plot. The physical causes for the sound- attenuation behavior are considered to be atmospheric diffraction and scattering effects. Statistical analysis of sod-intensity extremes indicated amplification of the sound signals by focusing which could be expected along selected azimuths. Empirical amplification values showed the maximum occurring in winter (50 decibels at 22 kilometers). For the analysis of correlation between empirical sound data and local atmospheric sound- propagation conditions, #e concept of analytical classification of sound-velocity profiles has been developed. Examination of over a quarter-million individual sound-velocity profiles indicates that 33 profile types for heights up to 3 kilometers constitute the empirical possibilities of sound-propagation conditions in southeastern United States. Since the focusing qualities of each sound- velocity profile can be determined as a class characteristic, the overall probabilities of focusing occurrence can he obtained. The severity of focusing, as based upon lateral spread of focusing areas, has been determined. The data for MTF indicate focusing is most severe in winter, with the direction toward east being most affected. Sound propagation is a fluctuating phenomenon because atmospheric conditions vary continuously. A measuring system for analyzing the nonstationary sound-propagation phenomena has been established. The analysis of the acoustic fluctuation data is sup- posed to provide "dynamic” perturbation functions of sound, which are to be superimposed on the related characteristic sound-velocity-profile type. The ultimate result of the program will be the establishment of reliable contingency tables showing the relationship between atmospheric parameters and far-field sound intensities. These data will be the basis for more accurate sound-propagation forecasting for static firing tests.

STATIC TESTING↗
DOE OSTI2022

Effect of proton irradiation temperature on persistent photoconductivity in zinc oxide metal-semiconductor-metal ultraviolet photodetectors

The electrical and structural characteristics of 50-nm-thick zinc oxide (ZnO) metal-semiconductor-metal ultraviolet (UV) photodetectors subjected to proton irradiation at different temperatures are reported and compared. The devices were irradiated with 200 keV protons to a fluence of 1016 cm−2. Examination of the x-ray diffraction (XRD) rocking curves indicates a preferred (100) orientation prior to irradiation, with decrease in crystal quality afterward. Additionally, peak shifts in XRD and Raman spectra of the control sample relative to well-known theoretical positions are indicative of tensile strain in the as-deposited ZnO films. Shifts toward theoretical unstrained positions are observed in the irradiated films, which indicates partial relaxation. Raman spectra also indicate increase in oxygen vacancies (VO) and zinc interstitial defects (Zni) compared to the control sample. Additionally, transient photocurrent measurements performed on each sample at different temperatures showed up to 2× increase in photocurrent decay time constants for irradiated samples vs the control. This persistent photoconductive behavior is linked to the activation of electron and hole traps near the surface, and to the desorption and reabsorption of O2 molecules on the ZnO surface under the influence of UV light. Using an Arrhenius model, trap activation energies were extracted and, by comparing with known energies from the literature, the dominant defects contributing to persistent photoconductivity for each irradiation condition were identified. The persistence of differences in photocurrent transients between different samples months after irradiation indicates that the defects introduced by the suppression of thermally activated dynamic annealing processes have a long-term deleterious effect on device performance.

Heuser, Thomas A. (ORCID:0000000225642400)↗
DOE OSTI2016

X-ray scattering study of pyrochlore iridates: Crystal structure, electronic, and magnetic excitations

We have investigated the structural, electronic, and magnetic properties of the pyrochlore iridates Eu 2 Ir 2 O 7 and Pr 2 Ir 2 O 7 using a combination of resonant elastic x-ray scattering, x-ray powder diffraction, and resonant inelastic x-ray scattering (RIXS). The structural parameters of Eu 2 Ir 2 O 7 have been examined as a function of temperature and applied pressure, with a particular emphasis on regions of the phase diagram where electronic and magnetic phase transitions have been reported. We find no evidence of crystal symmetry change over the range of temperatures (~6 to 300 K) and pressures (~0.1 to 17 GPa) studied. We have also investigated the electronic and magnetic excitations in single-crystal samples of Eu 2 Ir 2 O 7 and Pr 2 Ir 2 O 7 using high-resolution Ir L- 3 -edge RIXS. In spite of very different ground state properties, we find that these materials exhibit qualitatively similar excitation spectra, with crystal field excitations at ~3-5 eV, spin-orbit excitations at ~ 0.5-1 eV, and broad low-lying excitations below ~0.15 eV. In single-crystal samples of "Eu-rich" Eu 2 Ir 2 O 7 (found to possess an actual stoichiometry of Eu 2.18 Ir 1.82 O 7.06 ) we observe highly damped magnetic excitations at ~45 meV, which display significant momentum dependence. Here, we compare these results with recent dynamical structure factor calculations

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Molecular engineering to improve carrier lifetimes for organic photovoltaic devices with thick active layers

The morphology of the bulk heterojunction absorber layer in an organic photovoltaic (OPV) device has a profound effect on the electrical properties and efficiency of the device. Previous work has consistently demonstrated that the solubilizing side-chains of the donor material affect these properties and device performance in a non-trivial way. Here, using Time-Resolved Microwave Conductivity (TRMC), we show by direct measurements of carrier lifetimes that the choice of side chains can also make a substantial difference in photocarrier dynamics. We have previously demonstrated a correlation between peak photoconductance measured by TRMC and device efficiencies; here, we demonstrate that TRMC photocarrier dynamics have an important bearing on device performance in a case study of devices made from donor materials with linear vs. branched side-chains and with variable active layer thicknesses. We use Grazing-Incidence Wide Angle X-ray Scattering to elucidate the cause of the different carrier lifetimes as a function of different aggregation behavior in the polymers. Consequently, the results help establish TRMC as a technique for screening OPV donor materials whose devices maintain performance in thick active layers (>250 nm) designed to improve light harvesting, film reproducibility, and ease of processing.

14 SOLAR ENERGY↗
DOE OSTI2021

Early-Stage Aggregation and Crystalline Interactions of Peptoid Nanomembranes

Fully synthetic peptoid membranes are known to mimic important features of biological membranes, with several advantages over other biomimetic membranes. A fundamental understanding of how the individual peptoid amphiphiles assemble in solution to form the bilayer membrane is key to unlocking their versatility for application in a broad range of processes. Here, in this study, in situ X-ray scattering and molecular dynamics simulations are used to understand the early stages of assembly of three different peptoids that exhibit distinctly different crystallization kinetics. The in situ measurements reveal that the peptoids aggregate first into a nascent phase that is less crystalline than the assembled peptoid membrane. Anisotropic aromatic interactions are determined to be the dominant driving force in the early stages of membrane formation. These results provide key insights into how the peptoid assembly may be manipulated during the early stages of assembly and nucleation and growth.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Iron transformation pathways and redox micro-environments in seafloor sulfide-mineral deposits: Spatially resolved Fe XAS and δ 57/54 Fe observations

Hydrothermal sulfide chimneys located along the global system of oceanic spreading centers are habitats for microbial life during active venting. Hydrothermally extinct, or inactive, sulfide deposits also host microbial communities at globally distributed sites. The main goal of this study is to describe Fe transformation pathways, through precipitation and oxidation-reduction (redox) reactions, and examine transformation products for signatures of biological activity using Fe mineralogy and stable isotope approaches. The study includes active and inactive sulfides from the East Pacific Rise 9°50'N vent field. First, the mineralogy of Fe(III)-bearing precipitates is investigated using microprobe X-ray absorption spectroscopy (μXAS) and X-ray diffraction (μXRD). Second, laser-ablation (LA) and micro-drilling (MD) are used to obtain spatially-resolved Fe stable isotope analysis by multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS). Eight Fe-bearing minerals representing three mineralogical classes are present in the samples: oxyhydroxides, secondary phyllosilicates, and sulfides. For Fe oxyhydroxides within chimney walls and layers of Si-rich material, enrichments in both heavy and light Fe isotopes relative to pyrite are observed, yielding a range of δ 57 Fe values up to 6‰. Overall, several pathways for Fe transformation are observed. Pathway 1 is characterized by precipitation of primary sulfide minerals from Fe(II)aq-rich fluids in zones of mixing between vent fluids and seawater. Pathway 2 is also consistent with zones of mixing but involves precipitation of sulfide minerals from Fe(II)aq generated by Fe(III) reduction. Pathway 3 is direct oxidation of Fe(II) aq from hydrothermal fluids to form Fe(III) precipitates. Finally, Pathway 4 involves oxidative alteration of pre-existing sulfide minerals to form Fe(III). The Fe mineralogy and isotope data do not support or refute a unique biological role in sulfide alteration. The findings reveal a dynamic range of Fe transformation pathways consistent with a continuum of micro-environments having variable redox conditions. Lastly, these micro-environments likely support redox cycling of Fe and S and are consistent with culture-dependent and -independent assessments of microbial physiology and genetic diversity of hydrothermal sulfide deposits.

mineral alteration↗
DOE OSTI2018

Stress relaxation in quasi-two-dimensional self-assembled nanoparticle monolayers

Here, we experimentally probed the stress relaxation of a monolayer of iron oxide nanoparticles at the water-air interface. Upon drop-casting onto a water surface, the nanoparticles self-assembled into islands of two-dimensional hexagonally close packed crystalline domains surrounded by large voids. When compressed laterally, the voids gradually disappeared as the surface pressure increased. After the compression was stopped, the surface pressure (as measured by a Wilhelmy plate) evolved as a function of the film aging time with three distinct timescales. These aging dynamics were intrinsic to the stressed state built up during the non-equilibrium compression of the film. Utilizing x-ray photon correlation spectroscopy, we measured the characteristic relaxation time (tau) of in-plane nanoparticle motion as a function of the aging time through both second-order and two-time autocorrelation analysis. Compressed and stretched exponential fitting of the intermediate scattering function yielded exponents (beta) indicating different relaxation mechanisms of the films under different compression stresses. For a monolayer compressed to a lower surface pressure (between 20 mN/m and 30 mN/m), the relaxation time (tau) decreased continuously as a function of the aging time, as did the fitted exponent, which transitioned from being compressed (>1) to stretched (<1), indicating that the monolayer underwent a stress release through crystalline domain reorganization. However, for a monolayer compressed to a higher surface pressure (around 40 mN/m), the relaxation time increased continuously and the compressed exponent varied very little from a value of 1.6, suggesting that the system may have been highly stressed and jammed Despite the interesting stress relaxation signatures seen in these samples, the structural ordering of the monolayer remained the same over the sample lifetime, as revealed by grazing incidence x-ray diffraction.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Magnetism of Nd 2 O 3 single crystals near the Néel temperature

Single crystals of Nd 2 O 3 were grown and characterized using neutron scattering and thermodynamic measurements. Nd 2 O 3 has long-range antiferromagnetic order below T N =0.55 K and specific-heat measurements have demonstrated that a significant amount of the magnetic entropy is released above T N . Inelastic neutron scattering experiments reveal a magnetic mode(s) with little dispersion peaked at ≈0.37meV that is of greatest intensity below T N but persists above 2T N . This persistence of dynamic correlations is likely related to frustrated interactions associated with the nearly ideal stacked triangular lattice geometry of J eff =12 spins on Nd 3+ ions. Furthermore, the magnetization is observed to be strongly anisotropic at all temperatures due to crystal field effects, with easy-plane anisotropy observed. Additionally, a noncompensated magnetic structure is inferred from the temperature dependence of the magnetization when a magnetic field of sufficient strength is applied within the basal plane near T N , and the evolution of the long-range order is summarized in a temperature-field phase diagram.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Dual Atomic Coherence in the Self-Assembly of Patchy Heterostructural Nanocrystals

Advances in the synthesis and self-assembly of nanocrystals have enabled researchers to create a plethora of different nanoparticle superlattices. But while many super lattices with complex types of translational order have been realized, rotational order of nanoparticle building blocks within the lattice is more difficult to achieve. Self-assembled superstructures with atomically coherent nanocrystal lattices, which are desirable due to their exceptional electronic and optical properties, have been fabricated only for a few selected systems. Here, we combine experiments with molecular dynamics (MD) simulations to study the self-assembly of heterostructural nanocrystals (HNCs), consisting of a near-spherical quantum dot (QD) host decorated with a small number of epitaxially grown gold nanocrystal (Au NC) "patches ". Self-assembly of these HNCs results in face-centered-cubic (fcc) superlattices with well-defined orientational relationships between the atomic lattices of both QD hosts and Au patches. MD simulations indicate that the observed dual atomic coherence is linked to the number, size, and relative positions of gold patches. Here this study provides a strategy for the design and fabrication of NC superlattices with large structural complexity and delicate orientational order.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
NASA NTRS2021

SMD Technology Highlights

Six technology highlights from the Science Mission Directorate (SMD) Heliophysics, Astrophysics, Earth, and Biological and Physical Sciences divisions. Technologies featured include 1. the 1653 m2 Solar Cruiser Solar Sail Propulsion system to enable missions to reach novel and otherwise difficult or impossible destinations for observing the Sun. 2. Technology sponsored by NASA and developed by MIT Space Nanotechnology Lab is developing high-performance space instrumentation for more powerful future X-ray telescopes that will study the dynamics of the high-energy universe. 3. Active thermal control technology that will help enable large ultra-stable telescopes needed to detect and characterize Earth-like planets around other stars. 4. SMD sponsored high-performance infrared sensors with reduced requirements for cooling onboard satellites and these sensors could potentially be flown on small satellite platforms like CubeSats. 5. A new technology that will utilize electron beams/ultraviolet light to remove dust that could help protect future space assets and astronauts from dangerous effects that arise from Moon/Mars dust exposure. 6. Studies using model organisms on ISS to understand the impact of the spaceflight environment on organisms in preparation for long-duration missions.

solar sail↗
DOE OSTI2016

Eu 3+ -doped wide band gap Zn 2 SnO 4 semiconductor nanoparticles: Structure and luminescence

Nanocrystalline Zn 2 SnO 4 powders doped with Eu 3+ ions were synthesized via a mechanochemical solid-state reaction method followed by postannealing in air at 1200 °C. X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and Raman and photoluminescence (PL) spectroscopies provide convincing evidence for the incorporation of Eu 3+ ions into the host matrix on noncentrosymmetric sites of the cubic inverse spinel lattice. Microstructural analysis shows that the crystalline grain size decreases with the addition of Eu 3+ . Formation of a nanocrystalline Eu 2 Sn 2 O 7 secondary phase is also observed. Luminescence spectra of Eu 3+ -doped samples show several emissions, including narrow-band magnetic dipole emission at 595 nm and electric dipole emission at 615 nm of the Eu 3+ ions. Excitation spectra and lifetime measurements suggest that Eu 3+ ions are incorporated at only one symmetry site. According to the crystal field theory, it is assumed that Eu 3+ ions participate at octahedral sites of Zn 2+ or Sn 4+ under a weak crystal field, rather than at the tetrahedral sites of Zn2+, because of the high octahedral stabilization energy for Eu 3+ . Activation of symmetry forbidden (IR-active and silent) modes is observed in the Raman scattering spectra of both pure and doped samples, indicating a disorder of the cation sublattice of Zn 2 SnO 4 nanocrystallites. These results were further supported by the first principle lattice dynamics calculations. The spinel-type Zn 2 SnO 4 shows effectiveness in hosting Eu 3+ ions, which could be used as a prospective green/red emitter. As a result, this work also illustrates how sustainable and simple preparation methods could be used for effective engineering of material properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Structural evolution of iodine on approach to the monatomic state

Here, we applied single-crystal x-ray diffraction and Raman spectroscopy in a diamond-anvil cell up to 36 GPa and first-principles theoretical calculations to study the molecular dissociation of solid iodine at high pressure. Unlike previously reported, we find that the familiar Cmce molecular phase transforms to a Cmc2 1 molecular structure at 16 GPa, and then to an incommensurate polymeric Fmmm⁡(00⁢$\gamma$)⁢s⁢00 structure, which can be viewed as a mixture of molecular I 2 and zigzag chains of three iodine atoms, at 20 GPa. The available data are consistent with metallization of iodine at the boundary between the commensurate Cmc⁢2 1 structure and the incommensurate Fmmm⁡(00⁢$\gamma$)s⁢00 structure at 20 GPa.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Advanced Interactive 3D Visualization Tool for Customizable Analyses of Tomography Datasets in Material Science

Current methods for visualizing and analyzing 3D tomography datasets in materials science often lack the interactivity and depth required for detailed structural insights. This limitation restricts a researchers' ability to accurately interpret complex data, which is critical for advancing material innovations and understanding structural properties. To address this issue, we have developed a novel, web-based interactive 3D visualization and analysis tool from the Trame framework that offers customizable features to enhance data interpretability. The tool allows users to adjust parameters such as visible range, slice planes, data rotation, and layering, providing a more detailed and dynamic view of complex structures. Its user-friendly web interface increases the accessibility and ease of use for both novice and experienced researchers, to visualize large volumetric datasets. The tool supports a diverse range of data formats, making it versatile for various research applications. Unique capabilities include real-time data manipulation, automated feature detection, context-sensitive feedback, and real-time volume calculations and distributions per sliced region or layer, alongside the ability to quickly generate high-quality screenshots and videos for presentations and reports. These advancements offer a comprehensive solution for enhanced 3D data exploration, significantly improving the analysis process and communication of results in materials science.

36 - MATERIALS SCIENCE↗
DOE OSTI2023

WHONDRS River Corridor Sediment and Water Geochemistry and In Situ Sensor Data from Machine-Learning-Informed Sites across the Contiguous United States (v6)

This dataset supports a broader study examining hyporheic zone respiration rates to improve predictive models at a contiguous United States (CONUS) scale. The CONUS-Scale Model-Sample Study (CM) was designed following ICON (integrated, coordinated, open, and networked) principles to facilitate a model-experiment (ModEx) iteration approach, leveraging crowdsourced sampling across the CONUS. New machine learning models were created every month to guide sampling locations. Data from the resulting samples were used to test and rebuild the machine learning models for the next round of sampling guidance. Sampling began in April 2022 and ended in October 2023. In addition to the widely distributed CONUS sites, a more spatially focused sampling occurred in the Yakima River Basin, WA in summer 2022. Data from this more spatially intensive sampling occurred under the label “Second Spatial Study (SSS)” and were also included in the machine learning models. Other data types collected from SSS that were not part of CM were published in a separate data package (https://data.ess-dive.lbl.gov/view/doi:10.15485/1969566). This data package was originally published in February 2023. It was updated in June 2023 (v2; new and modified files); December 2023 (v3; new and modified files); June 2024 (v4; new and modified files); April 2024 (v5; new and modified files); and September 2025 (v6; modified files). See the change history section in the readme for more details. For details on how to navigate data packages generated by this project, see https://data.ess-dive.lbl.gov/portals/PNNLRiverCorridorSFA/About. This dataset is comprised of two folders of field photos and videos, one folder of raw Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) data and one main data folder containing (1) file-level metadata; (2) data dictionary; (3) field metadata; (4) readme; (5) international generic sample number (IGSN) mapping file; (6) field protocols; (7) a subfolder with sample data; and (8) a subfolder with sensor data. The sample data subfolder contains (1) surface water and sediment dissolved organic carbon (DOC, measured as non-purgeable organic carbon, NPOC) data and averages; (2) surface water and sediment total nitrogen data and averages; (3) surface water major cations and anions and averages; (4) sediment grain size data; (5) sediment iron (II) data and averages; (6) wet sediment mass, dry sediment mass, water mass, and wet sediment volume in incubation and sediment ICR vials; (7) sediment incubation respiration rate data and averages; (8) normalized respiration rate data and averages; (9) methods codes; (10) sediment specific surface area; (11) sediment percent carbon and nitrogen; (12) sediment gravimetric moisture and averages; (15) sediment X-ray diffraction (XRD) data; (16) sediment adenosine triphosphate (ATP) and averages; (17) a subfolder with sediment incubation respiration data, scripts, and plots; (18) surface water and sediment FTICR methods; and (19) a subfolder of 9.4 Tesla (9.4T) FTICR-MS data. This folder contains five subfolders, one containing the sediment .xml data files, one containing the water .xml files, one containing the sediment CoreMS output files, one containing the water CoreMS output files, and the other containing instructions and scripts for processing the files in CoreMS (https://github.com/EMSL-Computing/CoreMS).The sensor data subfolder contains (1) a subfolder with miniDOT dissolved oxygen and temperature data and plots; (2) miniDOT dissolved oxygen and temperature summary data; and (3) miniDOT installation methods. All files are .csv, .pdf, .R, .xml, .d, .html, .Rmd, .py, .cal, .json, .jpg, .jpeg, .png, .mov, or .mp4. CORRECTION: Carbon and nitrogen content are reported as percentages. The current column headers "01395_C_percent_per_mg" and "01397_N_percent_per_mg" are incorrect. These should read "01395_C_percent" and "01397_N_percent" and will be corrected in the next version of this data package. We thank the United States Forest Service, Washington Department of Fish and Wildlife, Washington Department of Natural Resources, Cowiche Canyon Conservatory, Washington State Parks and Recreation Commission (Scientific Research Permit #210901), and the Confederated Tribes and Bands of the Yakama Nation for access to field locations where the samples labeled “SSS” were collected. We also thank the Yakama Nation Tribal Council and Yakama Nation Fisheries for working with us to facilitate sample collection and optimization of data usage according to their values and worldview. WHONDRS consortium members were asked to provide any acknowledgments for the collection of samples labeled “CM” and the following is a list of acknowledgments that were submitted with their corresponding Site IDs: (MART) Research activities were conducted in part on the Wind River Experimental Forest within the Gifford Pinchot National Forest; (MP- 100379) Philadelphia is part of Lenapehoking, the ancestral homelands of the Lenape peoples; (MP-102398) Land surveyed is the ancestral homelands of the Nookhose'iinenno (Arapaho), Tsis tsis'tas (Cheyenne), and Nuuchu (Ute); (MP-100749 and MP- 100747) Georgia Coastal Ecosystem LTER, OCE-1832178; (SP-70 and SP-72) Eastern Shoshone, Shoshone-Bannock; (MP- 102944) Funded by Oregon Watershed Enhancement Board. On the traditional lands of the Confederated Tribes of the Siletz, Confederated Tribes of the Grand Rhonde, and the Clatsop-Nehalem Confederated Tribe; (MP- 100607) Holiday Creek is located on the traditional territory of the Monacan Indian Nation; (SP-45) Lafayette Blue Springs State Park; (MP-102420) NSF DEB-2016749; (MP-100019) New Hampshire Agriculture Experiment Station; (SP-35) Rayonier (land owner; https://www.rayonier.com/); (MP- 101276) US Department of Energy, Office of Science, Biological and Environmental Research, Subsurface Biogeochemical Research, Watershed Dynamics and Evolution SFA at ORNL; (MP- 103224) Watershed Dynamics and Evolution SFA at ORNL; (MP- 101584) Traditional lands of the Oceti Sakowin (Dakota, Lakota, Nakoda) and Anishinaabe Peoples.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Antiferromagnetism in semiconducting SrMn 2 Sb 2 and BaMn 2 Sb 2 single crystals

Here, crystals of SrMn 2 Sb 2 and BaMn 2 Sb 2 were grown using Sn flux and characterized by powder and single-crystal x-ray diffraction, respectively, and by single-crystal electrical resistivity ρ, heat capacity C p , and magnetic susceptibility χ measurements versus temperature T, and magnetization versus field M(H) isotherm measurements. SrMn 2 Sb 2 adopts the trigonal CaAl 2 Si 2 -type structure, whereas BaMn 2 Sb 2 crystallizes in the tetragonal ThCr 2 Si 2 -type structure. The ρ(T) data indicate semiconducting behaviors for both compounds with activation energies of ≳0.35 eV for SrMn 2 Sb 2 and 0.16 eV for BaMn 2 Sb 2 . The χ(T) and C p (T) data reveal antiferromagnetic (AFM) ordering at T N = 110 K for SrMn 2 Sb 2 and 450 K for BaMn 2 Sb 2 . The anisotropic χ(T≤T N ) data also show that the ordered moments in SrMn 2 Sb 2 are aligned in the hexagonal ab plane, whereas the ordered moments in BaMn 2 Sb 2 are aligned collinearly along the tetragonal c axis. The ab-plane M(H) data for SrMn 2 Sb 2 exhibit a continuous metamagnetic transition at low fields 0 2 Sb 2 exhibits no metamagnetic transitions up to 5.5 T. The χ(T) and C p (T) data for both SrMn 2 Sb 2 and BaMn 2 Sb 2 indicate strong dynamic short-range AFM correlations above their respective T N up to at least 900 K within a local-moment picture, corresponding to quasi-two-dimensional magnetic behavior. The present results and a survey of the literature for Mn pnictides with the CaAl 2 Si 2 and ThCr 2 Si 2 crystal structures show that the T N values for the CaAl 2 Si 2 -type compounds are much smaller than those for the ThCr 2 Si 2 -type materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

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