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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 OSTI2018

Excited-state vibronic wave-packet dynamics in H 2 probed by XUV transient four-wave mixing

The complex behavior of a molecular wave packet initiated by an extreme ultraviolet (XUV) pulse is investigated with noncollinear wave mixing spectroscopy. A broadband XUV pulse spanning 12-16 eV launches a wave packet in H 2 comprising a coherent superposition of multiple electronic and vibrational levels. The molecular wave packet evolves freely until a delayed few-cycle optical laser pulse arrives to induce nonlinear signals in the XUV via four-wave mixing (FWM). The angularly resolved FWM signals encode rich energy exchange processes between the optical laser field and the XUV-excited molecule. The noncollinear geometry enables spatial separation of ladder and V- or Λ-type transitions induced by the optical field. Ladder transitions, in which the energy exchange with the optical field is around 3 eV, appear off axis from the incident XUV beam. Each vibrationally revolved FWM line probes a different part of the wave packet in energy, serving as a promising tool for energetic tomography of molecular wave packets. V- or Λ-type transitions, in which the energy exchange is well under 1 eV, result in on-axis nonlinear signals. The first-order versus third-order interference of the on-axis signal serves as a mapping tool of the energy flow pathways. Intra- and interelectronic potential energy curve transitions are decisively identified. The current study opens possibilities for accessing complete dynamic information in XUV-excited complex systems.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2020

Enhanced X-ray diffraction of in vivo-grown μNS crystals by viscous jets at XFELs

μNS is a 70 kDa major nonstructural protein of avian reoviruses, which cause significant economic losses in the poultry industry. They replicate inside viral factories in host cells, and the μNS protein has been suggested to be the minimal viral factor required for factory formation. Thus, determining the structure of μNS is of great importance for understanding its role in viral infection. In the study presented here, a fragment consisting of residues 448–605 of μNS was expressed as an EGFP fusion protein in Sf9 insect cells. EGFP-μNS (448–605) crystallization in Sf9 cells was monitored and verified by several imaging techniques. Cells infected with the EGFP-μNS (448–605) baculovirus formed rod-shaped microcrystals (5–15 µm in length) which were reconstituted in high-viscosity media (LCP and agarose) and investigated by serial femtosecond X-ray diffraction using viscous jets at an X-ray free-electron laser (XFEL). The crystals diffracted to 4.5 Å resolution. A total of 4227 diffraction snapshots were successfully indexed into a hexagonal lattice with unit-cell parameters a = 109.29, b = 110.29, c = 324.97 Å. The final data set was merged and refined to 7.0 Å resolution. Preliminary electron-density maps were obtained. While more diffraction data are required to solve the structure of μNS (448–605) , the current experimental strategy, which couples high-viscosity crystal delivery at an XFEL with in cellulo crystallization, paves the way towards structure determination of the μNS protein.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Blunt Impact Brain Injury using Cellular Injury Criterion

The Advanced Combat Helmet (\ACH") military specification (\mil-spec") requires a helmeted magnesium (\Mg") Department of Transportation (\DOT") headform be dropped vertically, with an impact speed of 3.1 m/s (10 ft/s), onto a steel hemispherical target. The pass/fail criteria are based on translational acceleration (150 G) alone, absent of any rotational component. Without a rotational component, the specification's injury risk application is limited to skull fracture and peripheral hematomas (subdural, subarachnoid), since this translational acceleration injury risk assessment is based on the Wayne State Tolerance Curve (\WSTC"). To provide a more comprehensive view of injury for the entire brain, an alternative approach is needed. To meet this need, we worked with a larger group called PANTHER, a collaboration between national laboratories, industry, and academia. Collaborations specific to research and results presented here come from efforts led by Mr. Ron Szalkowski and Mr. Sushant Malave, Ms. Alice Fawzi, and Dr. Christian Franck. We have developed a prototypical injury risk criterion based on the neuronal response to abrupt changes in general motion (translation, rotation, or both). The cellular-based mild traumatic brain injury (\cbmTBI") criterion utilizes both the strain and strain rate of brain tissue to account for the stretch and rate of stretch that occurs throughout the brain as a result of blunt impact to the head. We conducted physical experiments of an ACH-fitted magnesium headform, which produced repeatable headform peak accelerations. Then, we developed a simulation of the experiment, and validated the simulation output with the experimental data. We then substituted the magnesium headform with a human headform, consisting of skin, muscle, bone, gray matter, white matter, cerebral-spinal fluid, membranes, vasculature, intravertebral discs, airway and sinus. We quantified brain injury risk using the cbmTBI criterion, using the current mil-spec test and a modified test. The modified mil-spec test used an inclined anvil target that was located posterior to the crown of the helmet in the axial plane. While the current mil-spec test produced brain deformation from head translation alone, the modified test produced brain deformation from head translation and rotation, which is closer to most real world and combat theater impacts (e.g., such as occur in tertiary blast exposure). Compared to the current mil-spec test, the modified test produced elevated strains in the human digital twin. These data, mapped to the cbmTBI criterion, suggest increased injury risk for blunt impacts that cause rotation and translation, rather than just translation alone. Moreover, these data may lead to a rotational performance metric, which is rooted in the biology and pathology of the brain's response to impact and blast, and which should be used to improve next-generation helmet designs.

42 ENGINEERING↗
DOE OSTI2023

Joint Inversion of Surface Electrical Resistivity Tomography and Seismic Refraction Data between the 200 Areas

Geologic stratigraphy on the Hanford Site influences groundwater and contaminant migration through the aquifer system and the vadose zone. The current geologic framework model (GFM) relies heavily on a sparse distribution of borehole data in some locations to map geologic contacts and hydrologic properties in the subsurface. Non-invasive geophysical methods such as electrical resistivity tomography (ERT), transient electromagnetic surveying, and seismic imaging are being used at Hanford to map subsurface structure in areas with limited well observations. This is to develop and mature the capability of geophysical methods to aid in GFM refinement, to identify regions of subsurface complexity, and for optimal well siting. A joint inversion of co-located seismic refraction and ERT data was carried out for data collected on a ~2.3-km profile between the 200 Areas on the Hanford Site. While ERT and seismic refraction images have sensitivity to overlapping physical properties (porosity, moisture content, lithology), the resolution and physics used to acquire each of these datasets are different and therefore information can be different or mutually complementary. Performing a joint inversion provides a reasonable option for a coherent, coupled interpretation for mutually complementary datasets. Between the 200 Areas, there are few boreholes to interpret the geologic framework model, and these data sets were obtained to provide a first line of evidence toward identifying stratigraphic structure. The seismic refraction and ERT data were independently inverted during fiscal year 2022 and broadly showed a two-layer structure with a trough-like feature that is ~1 km wide and upwards of 150 m deep. The depth of the trough feature was greater in the ERT image compared to the seismic image, which indicated a maximum depth of approximately 110 m. The objective of the joint inversion described in this report was to invert the seismic refraction and ERT data together while constraining the ERT image to be structurally similar to the seismic refraction image. The approach was applied using the geophysical inverse modeling program E4D, which has the capability to invert first-arrival times from seismic refraction data and ERT resistances using a “cross-gradient” constraint. The application of cross-gradient constraints with different weights produces ERT models that show a high degree of similarity within the upper 100 m (above ~120 m elevation). None of the ERT models show an improved structural similarity to the seismic result; therefore, it is recommended that further attempts to jointly interpret these models focus on petrophysics and image resolution. Petrophysical measurements of core samples would improve knowledge of what drives the ERT response in this region and, along with downhole geophysical measurements, could be used to “ground truth” the surface-based geophysical results. Image resolution studies would provide insight into which regions of the inverted images are reliable and which regions are poorly constrained.

58 GEOSCIENCES↗
DOE OSTI2025

CESER: wildfire mapping

Multispectral satellite imagery has been demonstrated to accurately detect wildfires over a variety of land cover types at coarse- and medium-resolution (i.e., 1km to 30m), typically by detecting burned area after the fire has caused substantial damage. We developed an algorithm to map active fire (i.e., flame) in 2-meter resolution WorldView time-series imagery and monitor fire trajectory over time. Our results depict robust mapping across scenes collected from different fires over grassy and forested land cover, identifying fires as small as 4m 2 throughout the image. Operational deployment at scale may provide valuable near-real time maps of active fire for responders to leverage for timely, targeted mitigation efforts. This white paper describes the current capability specifications and indicates requirements for scaling.

47 OTHER INSTRUMENTATION↗
NASA NTRS1982

The upper atmospheres of the earth and planets; Proceedings of the Topical Meeting, Ottawa, Canada, May 16-June 2, 1982

Various topics concerned with the upper atmosphere of the earth and planets are discussed. The atmospheres of the terrestrial planets are addressed, emphasizing Venus. The energy budget of the mesosphere and thermosphere is considered, discussing current and particles as energy sources, the radiation field, and neutral atmosphere dynamics. The results of Pre-Map Project One are covered, and the International Reference Ionosphere is discussed, including electron density profiles, the lower ionosphere, the plasmasphere, plasma temperature profiles, and ion composition. Finally, the mass spectroscopy of atmospheres is treated.

Barth, C. A.↗
NASA NTRS1987

A 1.6 MHz survey of the galactic background radio emission

Observations of the galactic radio emission at 1.6 MHz have been made during the current solar activity minimum using a radio telescope with a beamwidth of 25 deg. The radiation intensity was mapped for six declinations between -12 and -72 degrees and from 1000 to 0500 hours R.A.

Ellis, G. R. A.↗
NASA NTRS1990

Extensive middle atmosphere (20-120 KM) modification in the Global Reference Atmospheric Model (GRAM-90)

The Global Reference Atmospheric Model (GRAM) is currently available in the 'GRAM-88' version (Justus, et al., 1986; 1988), which includes relatively minor upgrades and changes from the 'MOD-3' version (Justus, et al., 1980). Currently a project is underway to use large amounts of data, mostly collected under the Middle Atmosphere Program (MAP) to produce a major upgrade of the program planned for release as the GRAM-90 version. The new data and program revisions will particularly affect the 25-90 km height range. Sources of data and preliminary results are described here in the form of cross-sectional plots.

Justus, C. G.↗
NASA NTRS1991

Space plasma and its origin at the sun

This paper provides a concise review of the large picture of space plasmas, concentrating on the heliosphere and the origin of the X-ray corona and coronal hole at the sun. It is tentatively suggested that the active X-ray corona is heated primarily by the dissipation of magnetic energy at the spontaneous tangential discontinuities (current sheets) in the confining bipolar magnetic fields of active regions. The discontinuities arise because of the continuous mapping of the footpoints of the field by the photospheric convection. The coronal holes appear to be heated by a combination of Alfven waves, providing the high-speed streams in the solar wind, and the microflaring in the small-scale network fields.

Parker, E. N.↗
NASA NTRS1999

Jupiter's Deep Flowing Thermocline

The observed banded wind structure of Jupiter and Saturn remains an outstanding problem in planetary fluid dynamics. Both planets exhibit super-rotational equatorial jets (exceeding the underlying rotation of the magnetic fields tied to their deep fluid interiors), with speeds of some 100 and 400m/s, respectively, and counter-flowing lots at higher latitudes;. Recent analyses of the 1995 Galileo probe measurements, Hubble Telescope observations of the 1994 Shoemaker-Levy9 comet crash, and Earth-based infrared mapping provide evidence for a variably stratified, deeply seated flow layer. A now conceptual model for the jovian current system is proposed, in some ways resembling the oceanic thermocline, assuming a mixed distribution of potential vorticity atop a tropospheric wind layer of latitudinally variable stratification. A simple analytic version of the model links the strength, shape, and direction of the alternating zonal currents on Jupiter and Saturn to a single parameter equivalent to the internal deformation scale for an inferred deep stable region.

Allison, Michael↗
NASA NTRS2003

The Global Three Dimensional Distribution and Temperature of Near-Surface Martian Ground Ice: New Results from MGS TES

We have discovered significant global-scale seasonal thermal anomalies in the MGS TES surface temperature observations that coincide spatially with the Odyssey GRS observations of enhanced near-surface hydrogen abundance. The TES thermal anomalies can be explained quantitatively by the widespread presence of cold, high thermal inertia material within millimeters to centimeters of the surface that we interpret as evidence for ground ice that must extend to depths of many meters. The results provide significant insights into the properties and processes that govern the behavior of Martian water under current climatic conditions, the surface geology of the planet, as well as much higher resolution Martian ground ice maps than have been previously available.

D A Paige↗
NASA NTRS2004

Chemical Compositions and Abundance Anomalies in Stellar Coronae ADP 99

New atomic data for tackling some of our spectra have been investigated by co-I Laming (NRL), including the effects of recombination on spectral line fluxes that are not included in, for example, the CHIANTI database models. Promising new progress has been made with modelling some of the recent abundance anomaly results in terms of Alven wave-driven separation of neutrals and ions in the upper chromosphere. The problems that existing models have is that they cannot simultaneously explain the low-FIP enhanced solar-like coronae and the high-FIP rich active coronae of RS CVn-like stars. The Alven wave model shows promise with both of these scenarios, with the fractionation or suppression of low-FIP ions depending on the characteristics of the chromosphere. This work is currently in the writing up stage. In summary, the work to-date is making good progress in mapping abundance anomalies as a function of spectral type and activity level. We are also making good progress with modelling that we will be able to test with our observational results. With one more year of effort, we'anticipate that the bulk of the work described above can be published, together with outstanding key studies on anomalies among the different active binaries.

Oliversen, Ronald J.↗
NASA NTRS2002

History of Nutrition in Space Flight: Overview

Major accomplishments in nutritional sciences for support of human space travel have occurred over the past 40 y. This article reviews these accomplishments, beginning with the early Gemini program and continuing through the impressive results from the first space station Skylab program that focused on life sciences research, the Russian contributions through the Mir space station, the US Shuttle life sciences research, and the emerging International Space Station missions. Nutrition is affected by environmental conditions such as radiation, temperature, and atmospheric pressures, and these are reviewed. Nutrition with respect to space flight is closely interconnected with other life sciences research disciplines including the study of hematology, immunology, as well as neurosensory, cardiovascular, gastrointestinal, circadian rhythms, and musculoskeletal physiology. These relationships are reviewed in reference to the overall history of nutritional science in human space flight. Cumulative nutritional research over the past four decades has resulted in the current nutritional requirements for astronauts. Space-flight nutritional recommendations are presented along with the critical path road map that outlines the research needed for future development of nutritional requirements.

Circadian rhythms↗
NASA NTRS2003

Gene Expression Dynamics Inspector (GEDI): for integrative analysis of expression profiles

Genome-wide expression profiles contain global patterns that evade visual detection in current gene clustering analysis. Here, a Gene Expression Dynamics Inspector (GEDI) is described that uses self-organizing maps to translate high-dimensional expression profiles of time courses or sample classes into animated, coherent and robust mosaics images. GEDI facilitates identification of interesting patterns of molecular activity simultaneously across gene, time and sample space without prior assumption of any structure in the data, and then permits the user to retrieve genes of interest. Important changes in genome-wide activities may be quickly identified based on 'Gestalt' recognition and hence, GEDI may be especially useful for non-specialist end users, such as physicians. AVAILABILITY: GEDI v1.0 is written in Matlab, and binary Matlab.dll files which require Matlab to run can be downloaded for free by academic institutions at http://www.chip.org/~ge/gedihome.html Supplementary information: http://www.chip.org/~ge/gedihome.html.

Database Management Systems↗
NASA NTRS2010

Use of Data Comm by Flight Crew in High-Density Terminal Areas

This paper describes a collaborative FAA and NASA experiment using 22 commercial airline pilots to determine the effect of using Datalink Communication (Data Comm) to issue messages in busy, terminal area operations. Four conditions were defined that span current day to future flight deck equipage levels (voice communication only, Data Comm only, Data Comm with Moving Map Display, Data Comm with Moving Map displaying taxi route), and each condition was used to create an arrival and a departure scenario at the Boston Logan Airport. These eight scenarios were repeated twice for a total of 16 scenarios for each of the eleven crews. Quantitative data was collected on subject reaction time and eye tracking information. Questionnaires collected subjective feedback on workload and acceptability to the flight crew for using Data Comm in a busy terminal area. 95% of the Data Comm messages were responded to by the flight crew within one minute; however, post experiment debrief comments revealed almost unanimous consensus that two minutes was a reasonable expectation for crew response. Eye tracking data indicated an insignificant decrease in head-up time for the Pilot Flying when Data Comm was introduced; however, the Pilot Monitoring had significantly less head-up time. Data Comm workload was rated as operationally acceptable by both crew members in all conditions in flight at any altitude above the Final Approach Fix in terms of response time and workload. Results also indicate the use of Data Comm during surface operations was acceptable, the exception being the simultaneous use of voice, Data Comm, and audio chime required for an aircraft to cross an active runway. Many crews reported they believed Data Comm messages would be acceptable after the Final Approach Fix or to cross a runway if the message was not accompanied by a chime and there was not a requirement to immediately respond to the uplink message.

Baxley, Brian T.↗
NASA NTRS2012

The Near-Earth Plasma Environment

An overview of the plasma environment near the earth is provided. We describe how the near-earth plasma is formed, including photo-ionization from solar photons and impact ionization at high latitudes from energetic particles. We review the fundamental characteristics of the earth's plasma environment, with emphasis on the ionosphere and its interactions with the extended neutral atmosphere. Important processes that control ionospheric physics at low, middle, and high latitudes are discussed. The general dynamics and morphology of the ionized gas at mid- and low-latitudes are described including electrodynamic contributions from wind-driven dynamos, tides, and planetary-scale waves. The unique properties of the near-earth plasma and its associated currents at high latitudes are shown to depend on precipitating auroral charged particles and strong electric fields which map earthward from the magnetosphere. The upper atmosphere is shown to have profound effects on the transfer of energy and momentum between the high-latitude plasma and the neutral constituents. The article concludes with a discussion of how the near-earth plasma responds to magnetic storms associated with solar disturbances.

Pfaff, Robert F., Jr.↗
NASA NTRS2018

Mapping Mangrove Extent and Change: A Globally Applicable Approach

This study demonstrates a globally applicable method for monitoring mangrove forest extent at high spatial resolution. A 2010 mangrove baseline was classified for 16 study areas using a combination of ALOS PALSAR and Landsat composite imagery within a random forests classifier. A novel map-to-image change method was used to detect annual and decadal changes in extent using ALOS PALSAR/JERS-1 imagery. The map-to-image method presented makes fewer assumptions of the data than existing methods, is less sensitive to variation between scenes due to environmental factors (e.g., tide or soil moisture) and is able to automatically identify a change threshold. Change maps were derived from the 2010 baseline to 1996 using JERS-1 SAR and to 2007, 2008 and 2009 using ALOS PALSAR. This study demonstrated results for 16 known hotspots of mangrove change distributed globally, with a total mangrove area of 2,529,760 ha. The method was demonstrated to have accuracies consistently in excess of 90% (overall accuracy: 92.2–93.3%, kappa: 0.86) for mapping baseline extent. The accuracies of the change maps were more variable and were dependent upon the time period between images and number of change features. Total change from 1996 to 2010 was 204,850 ha (127,990 ha gain, 76,860 ha loss), with the highest gains observed in French Guiana (15,570 ha) and the highest losses observed in East Kalimantan, Indonesia (23,003 ha). Changes in mangrove extent were the consequence of both natural and anthropogenic drivers, yielding net increases or decreases in extent dependent upon the study site. These updated maps are of importance to the mangrove research community, particularly as the continual updating of the baseline with currently available and anticipated spaceborne sensors. It is recommended that mangrove baselines are updated on at least a 5-year interval to suit the requirements of policy makers.

Thomas, Nathan↗
DOE OSTI2021

Distributed directory of named data elements in coordination namespace

An approach is described that provides a distributed directory structure within a storage of an information handling system (a local node). A request is received with the request corresponding to a shared virtual address. The shared virtual address that is shared amongst a number of nodes that includes the local node and some remote nodes. A Global Address Space Directory (GASD) is retrieved that corresponds to a global virtual address space. The GASD is stored in a Coordination Namespace that is stored in a memory that is distributed amongst the nodes. A mapping that is included in the GASD is used to determine the node where the shared virtual address currently resides. The shared virtual address is then accessed from the node where it currently resides.

Johns, Charles Ray↗