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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Spinoff 2010

Topics covered include: Burnishing Techniques Strengthen Hip Implants; Signal Processing Methods Monitor Cranial Pressure; Ultraviolet-Blocking Lenses Protect, Enhance Vision; Hyperspectral Systems Increase Imaging Capabilities; Programs Model the Future of Air Traffic Management; Tail Rotor Airfoils Stabilize Helicopters, Reduce Noise; Personal Aircraft Point to the Future of Transportation; Ducted Fan Designs Lead to Potential New Vehicles; Winglets Save Billions of Dollars in Fuel Costs; Sensor Systems Collect Critical Aerodynamics Data; Coatings Extend Life of Engines and Infrastructure; Radiometers Optimize Local Weather Prediction; Energy-Efficient Systems Eliminate Icing Danger for UAVs; Rocket-Powered Parachutes Rescue Entire Planes; Technologies Advance UAVs for Science, Military; Inflatable Antennas Support Emergency Communication; Smart Sensors Assess Structural Health; Hand-Held Devices Detect Explosives and Chemical Agents; Terahertz Tools Advance Imaging for Security, Industry; LED Systems Target Plant Growth; Aerogels Insulate Against Extreme Temperatures; Image Sensors Enhance Camera Technologies; Lightweight Material Patches Allow for Quick Repairs; Nanomaterials Transform Hairstyling Tools; Do-It-Yourself Additives Recharge Auto Air Conditioning; Systems Analyze Water Quality in Real Time; Compact Radiometers Expand Climate Knowledge; Energy Servers Deliver Clean, Affordable Power; Solutions Remediate Contaminated Groundwater; Bacteria Provide Cleanup of Oil Spills, Wastewater; Reflective Coatings Protect People and Animals; Innovative Techniques Simplify Vibration Analysis; Modeling Tools Predict Flow in Fluid Dynamics; Verification Tools Secure Online Shopping, Banking; Toolsets Maintain Health of Complex Systems; Framework Resources Multiply Computing Power; Tools Automate Spacecraft Testing, Operation; GPS Software Packages Deliver Positioning Solutions; Solid-State Recorders Enhance Scientific Data Collection; Computer Models Simulate Fine Particle Dispersion; Composite Sandwich Technologies Lighten Components; Cameras Reveal Elements in the Short Wave Infrared; Deformable Mirrors Correct Optical Distortions; Stitching Techniques Advance Optics Manufacturing; Compact, Robust Chips Integrate Optical Functions; Fuel Cell Stations Automate Processes, Catalyst Testing; Onboard Systems Record Unique Videos of Space Missions; Space Research Results Purify Semiconductor Materials; and Toolkits Control Motion of Complex Robotics.

Source record↗
NASA NTRS2022

Exploring the MeV Sky With A Combined Coded Mask and Compton Telescope: the Galactic Explorer With A Coded Aperture Mask Compton Telescope (GECCO)

The sky at MeV energies is currently poorly explored. Here we present an innovative mission concept that builds upon the heritage of past and current missions improving the sensitivity and, very importantly, the angular resolution. This consists in combining a Compton telescope and a coded-mask telescope. We delineate the motivation for such a concept and we define the scientific goals for such a mission. The Galactic Explorer with a Coded Aperture Mask Compton Telescope (GECCO) is a novel concept for a next-generation telescope covering hard X-ray and soft gamma-ray energies. The potential and importance of this approach that bridges the observational gap in the MeV energy range are presented. With the unprecedented angular resolution of the coded mask telescope combined with the sensitive Compton telescope, a mission such as GECCO can disentangle the discrete sources from the truly diffuse emission. Individual Galactic and extragalactic sources are detected. This also allows to understand the gamma-ray Galactic center excess and the Fermi Bubbles, and to trace the low-energy cosmic rays, and their propagation in the Galaxy. Nuclear and annihilation lines are spatially and spectrally resolved from the continuum emission and from sources, addressing the role of low-energy cosmic rays in star formation and galaxy evolution, the origin of the 511 keV positron line, fundamental physics, and the chemical enrichment in the Galaxy. Such an instrument also detects explosive transient gamma-ray sources, which, in turn, enables identifying and studying the astrophysical objects that produce gravitational waves and neutrinos in a multi-messenger context. By looking at a poorly explored energy band it also allows discoveries of new astrophysical phenomena.

Elena Orlando↗
NASA NTRS2021

A Large Fraction of Hydrogen-rich Supernova Progenitors Experience Elevated Mass Loss Shortly Prior to Explosion

Spectroscopic detection of narrow emission lines traces the presence of circumstellar mass distributions around massive stars exploding as core-collapse supernovae. Transient emission lines disappearing shortly after the supernova explosion suggest that the material spatial extent is compact and implies an increased mass loss shortly prior to explosion. Here, we present a systematic survey for such transient emission lines (Flash Spectroscopy) among Type II supernovae detected in the first year of the Zwicky Transient Facility survey. We find that at least six out of ten events for which a spectrum was obtained within two days of the estimated explosion time show evidence for such transient flash lines. Our measured flash event fraction (>30% at 95% confidence level) indicates that elevated mass loss is a common process occurring in massive stars that are about to explode as supernovae.

Rachel J. Bruch↗
NASA NTRS2009

Use of UV Sources for Detection and Identification of Explosives

Measurement of Raman and native fluorescence emission using ultraviolet (UV) sources (<400 nm) on targeted materials is suitable for both sensitive detection and accurate identification of explosive materials. When the UV emission data are analyzed using a combination of Principal Component Analysis (PCA) and cluster analysis, chemicals and biological samples can be differentiated based on the geometric arrangement of molecules, the number of repeating aromatic rings, associated functional groups (nitrogen, sulfur, hydroxyl, and methyl), microbial life cycles (spores vs. vegetative cells), and the number of conjugated bonds. Explosive materials can be separated from one another as well as from a range of possible background materials, which includes microbes, car doors, motor oil, and fingerprints on car doors, etc. Many explosives are comprised of similar atomic constituents found in potential background samples such as fingerprint oils/skin, motor oil, and soil. This technique is sensitive to chemical bonds between the elements that lead to the discriminating separability between backgrounds and explosive materials.

Hug, William↗
NASA NTRS1976

Gamma rays and supernova explosions

The detection of gamma rays from supernovae will provide interesting tests of current theory. Some current ideas on the expected gamma ray flux, as modified by recent theoretical results are reviewed.

Arnett, W. D.↗
NASA NTRS2012

Detection of Chemical Precursors of Explosives

Certain selected chemicals associated with terrorist activities are too unstable to be prepared in final form. These chemicals are often prepared as precursor components, to be combined at a time immediately preceding the detonation. One example is a liquid explosive, which usually requires an oxidizer, an energy source, and a chemical or physical mechanism to combine the other components. Detection of the oxidizer (e.g. H2O2) or the energy source (e.g., nitromethane) is often possible, but must be performed in a short time interval (e.g., 5 15 seconds) and in an environment with a very small concentration (e.g.,1 100 ppm), because the target chemical(s) is carried in a sealed container. These needs are met by this invention, which provides a system and associated method for detecting one or more chemical precursors (components) of a multi-component explosive compound. Different carbon nanotubes (CNTs) are loaded (by doping, impregnation, coating, or other functionalization process) for detecting of different chemical substances that are the chemical precursors, respectively, if these precursors are present in a gas to which the CNTs are exposed. After exposure to the gas, a measured electrical parameter (e.g. voltage or current that correlate to impedance, conductivity, capacitance, inductance, etc.) changes with time and concentration in a predictable manner if a selected chemical precursor is present, and will approach an asymptotic value promptly after exposure to the precursor. The measured voltage or current are compared with one or more sequences of their reference values for one or more known target precursor molecules, and a most probable concentration value is estimated for each one, two, or more target molecules. An error value is computed, based on differences of voltage or current for the measured and reference values, using the most probable concentration values. Where the error value is less than a threshold, the system concludes that the target molecule is likely. Presence of one, two, or more target molecules in the gas can be sensed from a single set of measurements.

Li, Jing↗
NASA NTRS2020

Optically targeted search for gravitational waves emitted by core-collapse supernovae during the first and second observing runs of advanced LIGO and advanced Virgo

We present the results from a search for gravitational-wave transients associated with core-collapse supernovae observed within a source distance of approximately 20 Mpc during the first and second observing runs of Advanced LIGO and Advanced Virgo. No significant gravitational-wave candidate was detected. We report the detection efficiencies as a function of the distance for waveforms derived from multidimensional numerical simulations and phenomenological extreme emission models. The sources with neutrino-driven explosions are detectable at the distances approaching 5 kpc, and for magnetorotationally driven explosions the distances are up to 54 kpc. However, waveforms for extreme emission models are detectable up to 28 Mpc. For the first time, the gravitational-wave data enabled us to exclude part of the parameter spaces of two extreme emission models with confidence up to 83%, limited by coincident data coverage. Besides, using ad hoc harmonic signals windowed with Gaussian envelopes, we constrained the gravitational-wave energy emitted during core collapse at the levels of 4.27 × 10^(−4) Mꙩc^(2) and 1.28 × 10^(−1) Mꙩc^(2) for emissions at 235 and 1304 Hz, respectively. These constraints are 2 orders of magnitude more stringent than previously derived in the corresponding analysis using initial LIGO, initial Virgo, and GEO 600 data.

B. P. Abbott↗
NASA NTRS2014

Fermi: The Gamma-Ray Large Area Telescope Mission Status

Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

gamma-ray↗
NASA NTRS2014

Fermi: The Gamma-Ray Large Area Space Telescope Mission Status

Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of a population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of gigaelectronvolts from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as super-symmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

telescope↗
NASA NTRS2015

Fermi: The Gamma-Ray Large Area Telescope

Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

telescope↗
NASA NTRS2014

Fermi: The Gamma-Ray Large Area Space Telescope

Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

telescope↗
NASA NTRS2014

Fermi: The Gamma-Ray Large Area Telescope

Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10 seconds of gigaelectronvolts from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as super-symmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

fermi↗
NASA NTRSDate not supplied

Cold Ocean Planets: Exoplanet Analogs of Our Solar System’s Icy Moons?

We have calculated total internal heating rates and depths to possible subsurface oceans for 17 planets that were previously characterized as rocky worlds but that are best described as Cold Ocean Planets. These low-mass exoplanets have equilibrium surface temperatures and/or densities that are consistent with icy surfaces and a substantial H2O content. While all planets in our study are likely to be covered in ice, estimated internal heating rates from tidal and radiogenic sources are large enough that they may harbor internal oceans and exhibit explosive cryovolcanism in the form of geyser-like plumes at their surfaces. Several of the icy moons in our solar system may thus serve as small-scale analogs of the Cold Ocean Planets in our study. We find that geological activity rates on these worlds are likely to exceed geological activity rates on Jupiter’s moon Europa and that several planets are likely to experience enhanced geological activity that exceeds that on Io. Owing to these planets’ thin ice shells, their expected high rates of internal heating, and their potential for tidally-induced explosive cryovolcanism, the identification of water vapor absorption features, especially given the expected time-variability of water vapor output during eruptions, could allow for the detection of geyser-like plumes on Trappist-1f, Proxima Cen b, and LHS 1140 b. Our study suggests that Cold Ocean Planets are habitable worlds at which the detection of explosive cryovolcanism could serve as indirect evidence of the presence of oceans beneath a layer of surface ice. Analyses of observational data from next-generation space telescopes and upcoming ground-based extremely large telescopes, and designs for future telescopic missions, should be undertaken with these results in mind.

Lynnae C Quick↗
NASA NTRS2005

On the Interaction and Coalescence if Spherical Blast Waves

The scaling and similarity laws concerning the propagation of isolated spherical blast waves are briefly reviewed. Both point source explosions and high pressure gas explosions are considered. Test data on blast overpressure from the interaction and coalescence of spherical blast waves emanating from explosives in the form of shaped charges of different strength placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure. The results point out the possibility of detecting source explosions from far-field pressure measurements.

Kandula, Max↗
NASA NTRS1997

Evaluating Possible Heating Mechanisms Using the Transition Region Line Profiles of Late-Type Stars

Our analysis of high-resolution Goddard High-Resolution Spectrograph (GHRS) spectra of late-type stars shows that the Si IV and C IV lines formed near 10(exp 5) K can be decomposed into the sum of two Gaussians, a broad component and a narrow component. We find that the flux contribution of the broad components is correlated with both the C IV and X-ray surface fluxes. For main-sequence stars, the widths of the narrow components suggest subsonic nonthermal velocities, and there appears to be a tight correlation between these nonthermal velocities and stellar surface gravity [xi(sub nc) varies as g(sup (-.68 +/-.07))]. For evolved stars with lower surface gravities, the nonthermal velocities suggested by the narrow components are at or just above the sound speed. Nonthermal velocities computed from the widths of the broad components are always highly supersonic. We propose that the broad components are diagnostics for microflare heating. Turbulent dissipation and Alfven waves are both viable candidates for the narrow component heating mechanism. A solar analog for the broad components might be the 'explosive events' detected by the High-Resolution Telescope and Spectrograph (HRTS) experiment. The broad component we observe for the Si IV lambda 1394 line of alpha Cen A, a star that is nearly identical to the Sun, has a FWHM of 109 +/- 10 km/s and is blueshifted by 9 +/- 3 km/s relative to the narrow component. Both of these properties are consistent with the properties of the solar explosive events. However, the alpha Cen A broad component accounts for 25% +/- 4% of the total Si IV line flux, while solar explosive events are currently thought to account for no more than 5% of the Sun's total transition region emission. This discrepancy must be resolved before the connection between broad components and explosive events can be positively established. In addition to our analysis of the Si IV and C IV lines of many stars, we also provide a more thorough analysis of all of the available GHRS data for alpha Cen A (G2 V) and alpha Cen B (K1 V). We find that the transition region lines of both stars have redshifts almost identical to those observed on the Sun: showing an increase with line formation temperature up to about log T = 5.2 and then a rapid decrease. Using the O IV] lines as density diagnostics, we compute electron densities of log n(sub e) = 9.65 +/- 0.20 and log n(sub e) = 9.50 +/- 0.30 for alpha Cen A and alpha Cen B, respectively.

Wood, Brian E.↗