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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

The Colorado East River Community Observatory Data Collection

Abstract The U.S. Department of Energy's (DOE) Colorado East River Community Observatory (ER) in the Upper Colorado River Basin was established in 2015 as a representative mountainous, snow‐dominated watershed to study hydrobiogeochemical responses to hydrological perturbations in headwater systems. The ER is characterized by steep elevation, geologic, hydrologic and vegetation gradients along floodplain, montane, subalpine, and alpine life zones, which makes it an ideal location for researchers to understand how different mountain subsystems contribute to overall watershed behaviour. The ER has both long‐term and spatially‐extensive observations and experimental campaigns carried out by the Watershed Function Scientific Focus Area (SFA), led by Lawrence Berkeley National Laboratory, and researchers from over 30 organizations who conduct cross‐disciplinary process‐based investigations and modelling of watershed behaviour. The heterogeneous data generated at the ER include hydrological, genomic, biogeochemical, climate, vegetation, geological, and remote sensing data, which combined with model inputs and outputs comprise a collection of datasets and value‐added products within a mountainous watershed that span multiple spatiotemporal scales, compartments, and life zones. Within 5 years of collection, these datasets have revealed insights into numerous aspects of watershed function such as factors influencing snow accumulation and melt timing, water balance partitioning, and impacts of floodplain biogeochemistry and hillslope ecohydrology on riverine geochemical exports. Data generated by the SFA are managed and curated through its Data Management Framework. The SFA has an open data policy, and over 70 ER datasets are publicly available through relevant data repositories. A public interactive map of data collection sites run by the SFA is available to inform the broader community about SFA field activities. Here, we describe the ER and the SFA measurement network, present the public data collection generated by the SFA and partner institutions, and highlight the value of collecting multidisciplinary multiscale measurements in representative catchment observatories.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Respiration regimes in rivers: Partitioning source–specific respiration from metabolism time series

Respiration in streams is controlled by the timing, magnitude, and quality of organic matter (OM) inputs from internal primary production and external fluxes. Here, we estimated the contribution of different OM sources to seasonal, annual, and event-driven characteristics of whole-stream ecosystem respiration (ER) using an inverse modeling framework that accounts for possible time-lags between OM inputs and respiration. We modeled site-specific, dynamic OM stocks contributing to ER: autochthonous OM from gross primary production (GPP); allochthonous OM delivered during flow events; and seasonal pulses of leaf litter. OM stored in the sediment and dissolved organic matter (DOM) transported during baseflow were modeled as a stable stock contributing to baseline respiration. We applied this modeling framework to five streams with different catchment size, climate, and canopy cover, where multi-year time series of ER and environmental variables were available. Overall, the model explained between 53% and 74% of observed ER dynamics. Respiration of autochthonous OM tracked seasonal peaks in GPP in spring or summer. Increases in ER were often associated with high-flow events. Respiration associated with litter inputs was larger in smaller streams. Time lags between leaf inputs and respiration were longer than for other OM sources, likely due to lower biological reactivity. Model estimates of source-specific ER and OM stocks compared well with existing measures of OM stocks, inputs, and respiration or decomposition. Our modeling approach has the potential to expand the scale of comparative analyses of OM dynamics within and among freshwater ecosystems.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Gamma-ray spectra analyses of molten salts in spent nuclear fuels pyroprocessing facilities for mass measurement

To evaluate radioactive tracer dilution and gamma spectroscopy as a safeguards technique for monitoring the mass of liquid salt in molten salt systems, the gamma spectroscopy data of salt samples from the pyroprocessing facilities in Idaho National Laboratory were acquired and analyzed. The primary focus is the uncertainty analysis of the gamma radioactivity of 154 Eu isotope in the molten salts. The facilities include an electrorefiner for pyroprocessing spent oxide fuels (SOF-ER) and Mark-IV ER for processing the metallic fuels from Experimental Breeder Reactor-II (EBR-II). The relative gamma radioactivity uncertainty was consistently at 3% for 137 Cs for both Mark-IV ER and SOF-ER salts. However, for 154 Eu, it was 8% for SOF-ER salt and 7% for Mark-IV ER salt. Here, the main reason for the higher uncertainty for 154 Eu is believed to be the lower counting statistics in gamma spectroscopy. To improve the gamma radioactivity uncertainty of isotope 154 Eu, a longer data acquisition time (12 h instead of 4 h) and a higher count rate gamma detector for gamma spectroscopy were tested and it was found that the uncertainty for 154 Eu was significantly improved from 7% or 8–3%.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Techno-economic and Life Cycle Analysis of MixAlco® Processes for Mixed Alcohol Production from Brown Algae

The need for producing renewable fuels from biomass has increased due to depleting fossil resources and environmental concerns. However, the low fraction of biomass carbon converted to product is an undeniable drawback for most current biofuel productions from fermentation due to undecomposed lignin in biomass composition and carbon loss as CO 2 . In this work, two main production routes of the MixAlco® process, the ketonization route (KR) and esterification route (ER) are evaluated for the mixed alcohol production by brown algae, a third-generation biomass without lignin. A novel fermentation process using syntrophic bacteria consortia (SBC) is developed to produce acetic acid from waste gas produced by KR and ER process. The paper investigates the integrated flowsheet for these alternative routes, using techno-economic and life cycle analysis to compare the minimum selling price and environmental impacts. From TEA, we find that the overall costs for KR and ER are lower than the SBC processes. The cost of ketonization routes is lower than esterification routes. The capital cost and operating cost for the ER+SBC process are the highest. Raw materials and utilities are the two major costs for all the processing routes examined. Here, the MSP for the ER+SBC process is the lowest out of all four routes. ER process performs the best in terms of environmental impacts except in water depletion compared with other processes, while the KR process performs the worst regarding the environmental metrics.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Signature analysis of high-throughput transcriptomics screening data for mechanistic inference and chemical grouping

Abstract High-throughput transcriptomics (HTTr) uses gene expression profiling to characterize the biological activity of chemicals in in vitro cell-based test systems. As an extension of a previous study testing 44 chemicals, HTTr was used to screen an additional 1,751 unique chemicals from the EPA’s ToxCast collection in MCF7 cells using 8 concentrations and an exposure duration of 6 h. We hypothesized that concentration-response modeling of signature scores could be used to identify putative molecular targets and cluster chemicals with similar bioactivity. Clustering and enrichment analyses were conducted based on signature catalog annotations and ToxPrint chemotypes to facilitate molecular target prediction and grouping of chemicals with similar bioactivity profiles. Enrichment analysis based on signature catalog annotation identified known mechanisms of action (MeOAs) associated with well-studied chemicals and generated putative MeOAs for other active chemicals. Chemicals with predicted MeOAs included those targeting estrogen receptor (ER), glucocorticoid receptor (GR), retinoic acid receptor (RAR), the NRF2/KEAP/ARE pathway, AP-1 activation, and others. Using reference chemicals for ER modulation, the study demonstrated that HTTr in MCF7 cells was able to stratify chemicals in terms of agonist potency, distinguish ER agonists from antagonists, and cluster chemicals with similar activities as predicted by the ToxCast ER Pathway model. Uniform manifold approximation and projection (UMAP) embedding of signature-level results identified novel ER modulators with no ToxCast ER Pathway model predictions. Finally, UMAP combined with ToxPrint chemotype enrichment was used to explore the biological activity of structurally related chemicals. The study demonstrates that HTTr can be used to inform chemical risk assessment by determining in vitro points of departure, predicting chemicals’ MeOA and grouping chemicals with similar bioactivity profiles.

Toxicology↗
DOE OSTI2023

Distinguishing erbium dopants in Y 2 O 3 by site symmetry: Ab initio theory of two spin-photon interfaces

Here, we present a first-principles study of the defect formation and electronic structure of erbium (Er)–doped yttria (Y 2 O 3 ). This is an emerging material for spin-photon interfaces in quantum information science due to the narrow-linewidth optical emission from Er dopants at standard telecommunication wavelengths and their potential for quantum memories and transducers. We calculate formation energies of neutral and negatively and positively charged Er dopants and find the charge-neutral configuration to be the most stable, consistent with experiment. Of the two substitutional sites of Er for Y, the C 2 (more relevant for quantum memories) and C 3i (more relevant for quantum transduction), we identify the former as possessing the lowest formation energy. The electronic properties are calculated using the Perdew-Burke-Ernzerhof functional along with the Hubbard U parameter and spin-orbit coupling, which yields a ~ 6 μ B orbital and a ~ 3 μ B spin magnetic moment, and 11 electrons in the Er 4 f shell, confirming the formation of charge-neutral Er 3+ . This standard density functional theory approach underestimates the band gap of the host and lacks a first-principles justification for U . To overcome these issues we performed screened hybrid functional calculations, including a negative U for the 4 f orbitals, with mixing (α) and screening (w) parameters. These produced robust electronic features with slight modifications in the band gap and the 4 f splittings depending on the choice of tuning parameters. We also computed the many-particle electronic excitation energies and compared them with experimental values from photoluminescence.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A temporal hierarchy underpins the transcription factor–DNA interactome of the maize UPR

Adverse environmental conditions reduce crop productivity and often increase the load of unfolded or misfolded proteins in the endoplasmic reticulum (ER). This potentially lethal condition, known as ER stress, is buffered by the unfolded protein response (UPR), a set of signaling pathways designed to either recover ER functionality or ignite programmed cell death. Despite the biological significance of the UPR to the life of the organism, the regulatory transcriptional landscape underpinning ER stress management is largely unmapped, especially in crops. To fill this significant knowledge gap, we performed a large–scale systems–level analysis of the protein–DNA interaction (PDI) network in maize (Zea mays). Using 23 promoter fragments of six UPR marker genes in a high–throughput enhanced yeast one–hybrid assay, we identified a highly interconnected network of 262 transcription factors (TFs) associated with significant biological traits and 831 PDIs underlying the UPR. We established a temporal hierarchy of TF binding to gene promoters within the same family as well as across different families of TFs. Cistrome analysis revealed the dynamic activities of a variety of cis–regulatory elements (CREs) in ER stress–responsive gene promoters. By integrating the cistrome results into a TF network analysis, we mapped a subnetwork of TFs associated with a CRE that may contribute to UPR management. Lastly, we validated the role of a predicted network hub gene using the Arabidopsis system. The PDIs, TF networks, and CREs identified in our work are foundational resources for understanding transcription–regulatory mechanisms in the stress responses and crop improvement.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on ErGaCo by Materials Project

ErCoGa crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 11-coordinate geometry to five equivalent Co and six equivalent Ga atoms. There are a spread of Er–Co bond distances ranging from 2.83–2.89 Å. There are a spread of Er–Ga bond distances ranging from 3.01–3.13 Å. Co is bonded in a 9-coordinate geometry to five equivalent Er and four equivalent Ga atoms. There are a spread of Co–Ga bond distances ranging from 2.52–2.58 Å. Ga is bonded in a 12-coordinate geometry to six equivalent Er and four equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCd2Cu by Materials Project

ErCuCd2 is Bergman Structure: Mg32(Al,Zn)49 Bergman-like structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to four equivalent Cu and eight equivalent Cd atoms. There are two shorter (2.99 Å) and two longer (3.50 Å) Er–Cu bond lengths. There are a spread of Er–Cd bond distances ranging from 3.11–3.21 Å. Cu is bonded in a 12-coordinate geometry to four equivalent Er and eight equivalent Cd atoms. There are a spread of Cu–Cd bond distances ranging from 2.87–3.24 Å. Cd is bonded in a 11-coordinate geometry to four equivalent Er, four equivalent Cu, and three equivalent Cd atoms. There are one shorter (2.90 Å) and two longer (3.06 Å) Cd–Cd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCoSn by Materials Project

ErCoSn crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 9-coordinate geometry to four equivalent Co and six equivalent Sn atoms. There are a spread of Er–Co bond distances ranging from 2.92–3.04 Å. There are a spread of Er–Sn bond distances ranging from 3.10–3.24 Å. Co is bonded in a 8-coordinate geometry to four equivalent Er and four equivalent Sn atoms. There are two shorter (2.61 Å) and two longer (2.63 Å) Co–Sn bond lengths. Sn is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCdCu4 by Materials Project

ErCu4Cd is Hexagonal Laves-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to twelve equivalent Cu and four equivalent Cd atoms. All Er–Cu bond lengths are 2.98 Å. All Er–Cd bond lengths are 3.11 Å. Cu is bonded to three equivalent Er, six equivalent Cu, and three equivalent Cd atoms to form a mixture of corner, edge, and face-sharing CuEr3Cd3Cu6 cuboctahedra. There are three shorter (2.53 Å) and three longer (2.55 Å) Cu–Cu bond lengths. All Cu–Cd bond lengths are 2.98 Å. Cd is bonded in a 4-coordinate geometry to four equivalent Er and twelve equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErGeAu by Materials Project

ErAuGe crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Er is bonded in a 8-coordinate geometry to six equivalent Au and five equivalent Ge atoms. There are three shorter (3.00 Å) and three longer (3.54 Å) Er–Au bond lengths. There are a spread of Er–Ge bond distances ranging from 2.86–3.09 Å. Au is bonded in a 6-coordinate geometry to six equivalent Er, two equivalent Au, and three equivalent Ge atoms. Both Au–Au bond lengths are 3.00 Å. All Au–Ge bond lengths are 2.98 Å. Ge is bonded to five equivalent Er and three equivalent Au atoms to form a mixture of edge and corner-sharing GeEr5Au3 hexagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er2InPd2 by Materials Project

Er2Pd2In crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to six equivalent Pd and four equivalent In atoms. There are two shorter (2.84 Å) and four longer (2.98 Å) Er–Pd bond lengths. All Er–In bond lengths are 3.39 Å. Pd is bonded in a 9-coordinate geometry to six equivalent Er, one Pd, and two equivalent In atoms. The Pd–Pd bond length is 2.79 Å. Both Pd–In bond lengths are 3.03 Å. In is bonded to eight equivalent Er and four equivalent Pd atoms to form a mixture of face and corner-sharing InEr8Pd4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErAsPd by Materials Project

ErPdAs crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 11-coordinate geometry to six equivalent Pd and five equivalent As atoms. There are a spread of Er–Pd bond distances ranging from 3.05–3.40 Å. There are a spread of Er–As bond distances ranging from 2.89–2.98 Å. Pd is bonded to six equivalent Er, two equivalent Pd, and four equivalent As atoms to form a mixture of distorted edge, face, and corner-sharing PdEr6As4Pd2 cuboctahedra. Both Pd–Pd bond lengths are 3.03 Å. There are a spread of Pd–As bond distances ranging from 2.62–2.81 Å. As is bonded in a 9-coordinate geometry to five equivalent Er and four equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErSnAu by Materials Project

ErAuSn crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to six equivalent Au and six equivalent Sn atoms. There are three shorter (2.98 Å) and three longer (3.67 Å) Er–Au bond lengths. There are three shorter (3.20 Å) and three longer (3.38 Å) Er–Sn bond lengths. Au is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Sn atoms. There are three shorter (2.82 Å) and one longer (2.93 Å) Au–Sn bond lengths. Sn is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErGePt by Materials Project

ErPtGe crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to six equivalent Pt and six equivalent Ge atoms. There are a spread of Er–Pt bond distances ranging from 2.99–3.24 Å. There are a spread of Er–Ge bond distances ranging from 3.01–3.22 Å. Pt is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Ge atoms. There are a spread of Pt–Ge bond distances ranging from 2.55–2.77 Å. Ge is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErAl7Au3 by Materials Project

ErAu3Al7 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to six equivalent Au and twelve equivalent Al atoms. All Er–Au bond lengths are 3.25 Å. There are six shorter (3.32 Å) and six longer (3.37 Å) Er–Al bond lengths. Au is bonded in a 9-coordinate geometry to two equivalent Er and seven Al atoms. There are a spread of Au–Al bond distances ranging from 2.59–2.67 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a distorted trigonal planar geometry to two equivalent Er and three equivalent Au atoms. In the second Al site, Al is bonded in a trigonal planar geometry to three equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCuPb by Materials Project

ErCuPb crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to three equivalent Cu and six equivalent Pb atoms. All Er–Cu bond lengths are 2.93 Å. There are three shorter (3.15 Å) and three longer (3.30 Å) Er–Pb bond lengths. Cu is bonded in a 7-coordinate geometry to three equivalent Er and four equivalent Pb atoms. There are three shorter (2.75 Å) and one longer (2.93 Å) Cu–Pb bond lengths. Pb is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Cu atoms.

36 MATERIALS SCIENCE↗