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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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At least 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Deep Green Unannotated Protein Structures

The Deep Green list is based on the identification and curation of conserved unannotated proteins in three green lineage (Viridiplantae) model organisms; Arabidopsis thaliana, Chlamydomonas reinhardtii, and Setaria viridis. Preliminary characterization of Deep Green proteins and genes was done using various informatics tools and published data sets and is presented in Knoshaug, Sun, et al., 2023, submitted. The structures of these unannotated proteins were also predicted using AlphaFold (Jumper et al., 2021). The data deposited here are the AlphaFold structural predictions having the highest pLDDT score and thus identified as the best folded structure (ranked_0). These data enable others to do in-depth structural characterizations to aid in functional characterization leading to deeper understanding of plant biology. References: Jumper, J., Evans, R., Pritzel, A., Green, T., Figurnov, M., Ronneberger, O., Tunyasuvunakool, K., Bates, R., Žídek, A., Potapenko, A., Bridgland, A., Meyer, C., Kohl, S. A. A., Ballard, A. J., Cowie, A., Romera-Paredes, B., Nikolov, S., Jain, R., Adler, J., Back, T., Petersen, S., Reiman, D., Clancy, E., Zielinski, M., Steinegger, M., Pacholska, M., Berghammer, T., Bodenstein, S., Silver, D., Vinyals, O., Senior, A. W., Kavukcuoglu, K., Kohli, P. and Hassabis, D. (2021) Highly accurate protein structure prediction with AlphaFold. Nature, 596:583-589. Knoshaug, E. P., Sun, P., Nag, A., Nguyen, H., Mattoon, E. M., Zhang, N., Liu, J., Chen, C., Cheng, J., Zhang, R., St. John, P., and Umen, J. (submitted) Identification and preliminary characterization of conserved uncharacterized proteins from Chlamydomonas reinhardtii, Arabidopsis thaliana, and Setaria viridis.

09 BIOMASS FUELS↗
NASA NTRS1989

Flexible backbone aromatic polyimide adhesives

Continuing research at Langley Research Center on the synthesis and development of new inexpensive flexible aromatic polyimides as adhesives has resulted in a material identified as LARC-F-SO2 with similarities to polyimidesulfone, PISO2, and other flexible backbone polyimides recently reported by Progar and St. Clair. Also prepared and evaluated was an endcapped version of PISO2. These two polymers were compared with LARC-TPI and LARC-STPI, polyimides research in our laboratory and reported in the literature. The adhesive evaluation, primarily based on lap shear strength (LSS) tests at RT, 177 C and 204 C, involved preparing adhesive tapes, conducting bonding studies and exposing lap shear specimens to 204 C air for up to 1000 hrs and to a 72-hour water boil. The type of adhesive failure as well as the Tg was determined for the fractured specimens. The results indicate that LARC-TPI provides the highest LSSs. LARC-F-SO2, LARC-TPI and LARC-STPI all retain their strengths after thermal exposure for 1000 hrs and PISO2 retains greater than 80 percent of its control strengths. After a 72-hr water boil exposure, most of the four adhesive systems showed reduced strengths for all test temperatures although still retaining a high percentage of their original strength (greater than 60 percent) except for one case. The predominant failure type was cohesive with no significant change in the Tgs.

Progar, Donald J.↗
NASA NTRS2006

The ST7-DRS Mission: Status and Plans

ST-7 is developing enabling drag-free control technology with low noise micro-thrusters and drag-free control algorithms. The flight computer & dynamic control software are complete, and colloid micro-newton thrusters are beginning ground-based performance testing.

LISA Pathfrinder↗
NASA NTRS2019

Validation of ICESat-2 ATLAS Bathymetry and Analysis of ATLAS’s Bathymetric Mapping Performance

NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) was launched in September, 2018. The satellite carries a single instrument, ATLAS (Advanced Topographic Laser Altimeter System), a green wavelength, photon-counting lidar, enabling global measurement and monitoring of elevation with a primary focus on the cryosphere. Although bathymetric mapping was not one of the design goals for ATLAS, pre-launch work by our research team showed the potential to map bathymetry with ICESat-2, using data from MABEL (Multiple Altimeter Beam Experimental Lidar), NASA’s high-altitude airborne ATLAS emulator, and adapting the laser-radar equation for ATLAS specific parameters. However, many of the sensor variables were only approximations, which limited a full assessment of the bathymetric mapping capabilities of ICESat-2 during pre-launch studies. Following the successful launch, preliminary analyses of the geolocated photon returns have been conducted for a number of coastal sites, revealing several salient examples of seafloor detection in water depths of up to ~40 m. The geolocated seafloor photon returns cannot be taken as bathymetric measurements, however, since the algorithm used to generate them is not designed to account for the refraction that occurs at the air–water interface or the corresponding change in the speed of light in the water column. This paper presents the first early on-orbit validation of ICESat-2 bathymetry and quantification of the bathymetric mapping performance of ATLAS using data acquired over St. Thomas, U.S. Virgin Islands. A refraction correction, developed and tested in this work, is applied, after which the ICESat-2 bathymetry is compared against high-accuracy airborne topo-bathymetric lidar reference data collected by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). The results show agreement to within 0.43—0.60 m root mean square error (RMSE) over 1 m grid resolution for these early on-orbit data. Refraction-corrected bottom return photons are then inspected for four coastal locations around the globe in relation to Visible Infrared Imaging Radiometer Suite (VIIRS) K(d)(490) data to empirically determine the maximum depth mapping capability of ATLAS as a function of water clarity. It is demonstrated that ATLAS has a maximum depth mapping capability of nearly 1 Secchi in depth for water depths up to 38 m and K(d)(490) in the range of 0.05–0.12 per m. Collectively, these results indicate the great potential for bathymetric mapping with ICESat-2, offering a promising new tool to assist in filling the global void in nearshore bathymetry.

ICESat-2↗
DOE OSTI2015

Geothermal play-fairway analysis of Washington State prospects

Herein, analysis of existing geologic, geophysical, and geochemical data revealed areas with elevated heat and permeability, defining three promising plays along the central axis of the magmatic arc of Washington State: Mount St. Helens, Wind River valley, and the southeast flank of Mount Baker. These areas are geothermal ‘fairways’, or locations with high geothermal resource potential based on modeling. This project applies innovative data analyses (Poly3D) in conjunction with methods proven in previous geothermal favorability studies (ArcGIS and MATLAB) to extract new value from existing public data. Heat and permeability potential models for each play are weighted using the Analytical Hierarchy Process, and combined to map geothermal resource potential and locations for further data collection at each site. Heat potential is based on: (1) temperature gradients, (2) volcanic vents, (3) Quaternary intrusive rocks, (4) spring temperature, and (5) spring geothermometry. Permeability potential is based on: (1) slip and (2) dilation tendency on mapped and seismic faults (3) maximum shear strain rate, and (4) dilatational strain rate at the surface, (5) modeled fault displacement distribution, and (6) displacement gradient, (7) shear, and (8) tensile fracture density, and (9) local geology and geophysical data. This information is vital for revealing the small scale heat and permeability potential of each study area, locating areas of undiscovered or untapped resources, and reducing the risk and cost involved in greenfield exploration and development. Preliminary analysis of the three play areas shows promise for geothermal development. Uncertainty modeling is underway and the results will guide future exploration plans.

15 GEOTHERMAL ENERGY↗
DOE OSTI2017

Geothermal Play-Fairway Analysis of Washington State Prospects: Phase 2 Results

An investment of $0.7M from the Geothermal Technology Office for Phase 2 of Play Fairway Analysis in Washington State improved existing favorability models and increased model confidence. The new 1:24,000-scale geological mapping, 15 detailed geophysical surveys, 2 passive seismic surveys, and geochronology collected during this phase are coupled with updated and detailed structural modeling and have significantly improved the conceptual models of three potential blind geothermal systems/plays in Washington State: the St. Helens Shear Zone, Mount Baker, and Wind River Valley. Results of this analysis reveal the presence of commercially viable undiscovered geothermal resources in all three study areas. The analysis additionally provides a clear definition of the geothermal prospects in terms of the essential elements of a functioning geothermal system, the confidence in these assessments, and associated potential and risk of development. As a result, several groups have recently approached our organization about opportunities for large-capital moderate- to high-temperature geothermal development and are very interested in the results of Phase 3 drilling. Here, our updated models, coupled with development interest, provides a compelling basis for investment in future validation activities.

exploration risk↗
DOE OSTI2015

On the use of remote infrasound and seismic stations to constrain the eruptive sequence and intensity for the 2014 Kelud eruption

The February 2014 eruption of Kelud volcano (Indonesia) destroyed most of the instruments near it. We use remote seismic and infrasound sensors to reconstruct the eruptive sequence. The first explosions were relatively weak seismic and infrasound events. A major stratospheric ash injection occurred a few minutes later and produced long-lasting atmospheric and ground-coupled acoustic waves that were detected as far as 11,000 km by infrasound sensors and up to 2300 km away on seismometers. A seismic event followed ~12 minutes later and was recorded 7000 km away by seismometers. We estimate a volcanic intensity around 10.9, placing the 2014 Kelud eruption between the 1980 Mount St. Helens and 1991 Pinatubo eruptions intensities. As a result, we demonstrate how remote infrasound and seismic sensors are critical for the early detection of volcanic explosions, and how they can help to constrain and understand eruptive sequences.

58 GEOSCIENCES↗
DOE OSTI2016

The Global Positioning System constellation as a space weather monitor. Comparison of electron measurements with Van Allen Probes data

Energetic electron observations in Earth's radiation belts are typically sparse, and multipoint studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross calibration into two parts—one that removes any spectral assumptions from the CXD flux calculation and one that compares the energy spectra—we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra, we use a combination of four distributions that together capture a wide range of observed spectral shapes. Moreover, our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer and Relativistic Electron-Proton Telescope on Van Allen Probes as a “gold standard,” here we demonstrate that the CXD instruments are well understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies inline image4 MeV. Our team present data from 17 CXD-equipped GPS satellites covering the 2015 “St. Patrick's Day” geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

Magnetic Field Enhancement of Organic Light‐Emitting Diodes Based on Electron Donor–Acceptor Exciplex

Reverse intersystem crossing (RISC) from triplet to singlet states has been recently introduced to photophysics of organic chromophores. One type of RISC occurs in donor (D)–acceptor (A) composites that form an exciplex manifold in which the energy difference, Δ E ST between the lowest singlet (S 1 ) and triplet (T 1 ) levels of the exciplex is small (<100 meV) thus allowing RISC at room temperature. This adds a delayed component to the photoluminescence emission that is widely known as thermally activated delayed fluorescence. Here, it is found that the electroluminescence in organic light‐emitting diodes (OLED) based on electron D–A exciplex is significantly enhanced (up to ≈40%) by applying magnetic field, due to the existence of an additional spin‐mixing channel between singlet and triplet states in the exciplex. The large magneto‐electroluminescence (MEL) in N , N , N ′, N ′‐tetrakis(4‐methoxyphenyl)benzidine: tris‐[3‐(3‐pyridyl)mesityl]borane [D–A] based OLEDs is demonstrated. These results are supported by magneto‐photoluminescence (MPL) measurements, and density functional theory calculations. Importantly, it is found that both MEL and MPL are thermally activated indicating the dominant role of the RISC process. The MEL( B ) response using the Δ g mechanism is analyzed, where the electron and hole g ‐values are different from each other because they reside in different molecules.

Basel, Tek↗
DOE OSTI2024

Identifying and Amplifying the Spontaneously Formed Photo‐Charge Contribution in Opaque and Semitransparent Organic Photovoltaics

Abstract Spontaneous photo‐charge (SP) generation within the non‐fullerene (NFA) bulk helps avoid exciton (EX) related loss as compared to the traditional heterojunction route in organic solar cells (OSCs). Unfortunately, the promising SP utilization attracts little attention at this time due to the lack of knowledge on its specific contribution to the photovoltaic performance and rational optimization in high‐efficiency devices. To fill the gap, the NFAs’ SP characteristics are related with their photocurrent loss and power conversion efficiency (PCE) in state‐of‐the‐art materials. Though higher SP population is good for efficient EX utilization, it simultaneously acts as an additional photo‐charge recombination channel. The former can be further enhanced by increasing the NFAs’ crystallinity with preferred lamellar growth, and the latter can be suppressed via electric doping. With the aid of the two‐step optimization strategy, the total photocurrent loss is reduced from 14.4% to 4.8%, accompanying with PCE increment from 16.9% to 18.5%. The SP utilization strategy is finally applied in the semitransparent OSCs (ST‐OSCs), due to its less heterojunction area sensitive photo‐charge generation characteristic. A light utilization efficiency (LUE) is then increased from 3.21% to 3.77%. The findings highlight the pursue of efficient SP utilization as a new design philosophy in future OSCs’ progresses.

Chemistry↗
DOE OSTI2016

Toward high solids loading process for lignocellulosic biofuel production at a low cost: Biofuel Production at High Solids Loading

High solids loadings (>18 wt%) in enzymatic hydrolysis and fermentation are desired for lignocellulosic biofuel production at a high titer and low cost. However, sugar conversion and ethanol yield decrease with increasing solids loading. The factor(s) limiting sugar conversion at high solids loading is not clearly understood. In the present study, we investigated the effect of solids loading on simultaneous saccharification and co-fermentation (SSCF) of AFEX™ (ammonia fiber expansion) pretreated corn stover for ethanol production using a xylose fermenting strain Saccharomyces cerevisiae 424A(LNH-ST). Decreased sugar conversion and ethanol yield with increasing solids loading were also observed. End-product (ethanol) was proven to be the major cause of this issue and increased degradation products with increasing solids loading was also a cause. For the first time, we show that with in situ removal of end-product by performing SSCF aerobically, sugar conversion stopped decreasing with increasing solids loading and monomeric sugar conversion reached as high as 93% at a high solids loading of 24.9 wt%. In this work, techno-economic analysis was employed to explore the economic possibilities of cellulosic ethanol production at high solids loadings. The results suggest that low-cost in situ removal of ethanol during SSCF would significantly improve the economics of high solids loading processes.

09 BIOMASS FUELS↗
DOE OSTI2022

Vanadium (II) Sulfate for the Reductive Leaching of Chalcopyrite: Replacing Smelting with Electrolysis for Copper Production

The demand for copper is expected to outpace supply in the coming decades due in part to the emergence of wind and solar technologies, which require about five times as much copper as traditional energy sources. This work introduces a potentially transformative hydrometallurgical process to extract copper from chalcopyrite, and thereby sustain a high rate of copper production throughout the 21 st century. Chalcopyrite is reacted with vanadium (II) sulfate for the first time to enable the rapid, clean, and complete recovery of copper. Reactions between 39 g/L copper concentrate, 1 M vanadium (II) sulfate, and various concentrations of sulfuric acid yielded a final product of solid copper sulfate, which was characterized by X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis. The solid products were leached in a subsequent step to demonstrate copper yields ranging from 95–99%. The vanadium (II) ion may be regenerated by an electrolysis unit that leverages advances in vanadium flow battery technologies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Spatially explicit network analysis reveals multi‐species annual cycle movement patterns of sea ducks

Abstract Conservation of long‐distance migratory species poses unique challenges. Migratory connectivity, that is, the extent to which groupings of individuals at breeding sites are maintained in wintering areas, is frequently used to evaluate population structure and assess use of key habitat areas. However, for species with complex or variable annual cycle movements, this traditional bimodal framework of migratory connectivity may be overly simplistic. Like many other waterfowl, sea ducks often travel to specific pre‐ and post‐breeding sites outside their nesting and wintering areas to prepare for migration by feeding extensively and, in some cases, molting their flight feathers. These additional migrations may play a key role in population structure, but are not included in traditional models of migratory connectivity. Network analysis, which applies graph theory to assess linkages between discrete locations or entities, offers a powerful tool for quantitatively assessing the contributions of different sites used throughout the annual cycle to complex spatial networks. We collected satellite telemetry data on annual cycle movements of 672 individual sea ducks of five species from throughout eastern North America and the Great Lakes. From these data, we constructed a multi‐species network model of migratory patterns and site use over the course of breeding, molting, wintering, and migratory staging. Our results highlight inter‐ and intra‐specific differences in the patterns and complexity of annual cycle movement patterns, including the central importance of staging and molting sites in James Bay, the St. Lawrence River, and southern New England to multi‐species annual cycle habitat linkages, and highlight the value of Long‐tailed Ducks ( Calengula haemalis ) as an umbrella species to represent the movement patterns of multiple sea duck species. We also discuss potential applications of network migration models to conservation prioritization, identification of population units, and integrating different data streams.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Population genomics of the eastern cottonwood ( Populus deltoides )

Abstract Despite its economic importance as a bioenergy crop and key role in riparian ecosystems, little is known about genetic diversity and adaptation of the eastern cottonwood ( Populus deltoides ). Here, we report the first population genomics study for this species, conducted on a sample of 425 unrelated individuals collected in 13 states of the southeastern United States. The trees were genotyped by targeted resequencing of 18,153 genes and 23,835 intergenic regions, followed by the identification of single nucleotide polymorphisms ( SNP s). This natural P. deltoides population showed low levels of subpopulation differentiation ( F ST = 0.022–0.106), high genetic diversity (θ W = 0.00100, π = 0.00170), a large effective population size ( N e ≈ 32,900), and low to moderate levels of linkage disequilibrium. Additionally, genomewide scans for selection (Tajima's D ), subpopulation differentiation ( X T X ), and environmental association analyses with eleven climate variables carried out with two different methods ( LFMM and BAYENV 2) identified genes putatively involved in local adaptation. Interestingly, many of these genes were also identified as adaptation candidates in another poplar species, Populus trichocarpa , indicating possible convergent evolution. This study constitutes the first assessment of genetic diversity and local adaptation in P. deltoides throughout the southern part of its range, information we expect to be of use to guide management and breeding strategies for this species in future, especially in the face of climate change.

54 ENVIRONMENTAL SCIENCES↗