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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Linear Subpixel Learning Algorithm for Land Cover Classification from WELD using High Performance Computing

In this work, we use a Fully Constrained Least Squares Subpixel Learning Algorithm to unmix global WELD (Web Enabled Landsat Data) to obtain fractions or abundances of substrate (S), vegetation (V) and dark objects (D) classes. Because of the sheer nature of data and compute needs, we leveraged the NASA Earth Exchange (NEX) high performance computing architecture to optimize and scale our algorithm for large-scale processing. Subsequently, the S-V-D abundance maps were characterized into 4 classes namely, forest, farmland, water and urban areas (with NPP-VIIRS-national polar orbiting partnership visible infrared imaging radiometer suite nighttime lights data) over California, USA using Random Forest classifier. Validation of these land cover maps with NLCD (National Land Cover Database) 2011 products and NAFD (North American Forest Dynamics) static forest cover maps showed that an overall classification accuracy of over 91 percent was achieved, which is a 6 percent improvement in unmixing based classification relative to per-pixel-based classification. As such, abundance maps continue to offer an useful alternative to high-spatial resolution data derived classification maps for forest inventory analysis, multi-class mapping for eco-climatic models and applications, fast multi-temporal trend analysis and for societal and policy-relevant applications needed at the watershed scale.

Subpixel↗
NASA NTRSDate not supplied

A Simulated Fire Edge Vis-IR Detection and Tracking Approach for Autonomous sUAS in STEReO

This study presents a fire edge detection and tracking methodology for an autonomous small UAS (sUAS). The sUAS, onboard sensors, and wildfire are simulated to evaluate the methodology. A visible light (Vis) camera and an infrared (IR) camera are simulated onboard the sUAS to identify burnt, burning, and unburnt areas on a static wildfire bitmap. After differentiating between these areas, a form of nonlinear guidance law (NLGL) is used to generate virtual target points (VTP) that guide the sUAS so that the fire edge is kept within the camera FOV. The VTP are passed to the sUAS flight management system (FMS) in the form of waypoints. The approach was tested in simulation and demonstrated tracking curved, sharp, and linear fire edge shapes at different altitudes. Higher altitude tracking proved to demand the least control effort without sacrificing continuous tracking.

Autonomous UAV↗
NASA NTRS2021

Air Pollution Scenario over Pakistan: Characterization and Ranking of Extremely Polluted Cities using Long-Term Concentrations of Aerosols and Trace Gases

Pakistan ranks third in the world in terms of mortality attributable to air pollution, with aerosol mass concentrations (PM2.5) consistently well above WHO (World Health Organization) air quality guidelines (AQG). However, regulation is dependent on a sparse network of air quality monitoring stations and insufficient ground data. This study utilizes long-term observations of aerosols and trace gases to characterize and rank the air pollution scenarios and pollution characteristics of 80 selected cities in Pakistan. Datasets used include (1) the Aqua and Terra (AquaTerra) MODIS (Moderate Resolution Imaging Spectroradiometer) Level 2 Collection 6.1 merged Dark Target and Deep Blue (DTB) aerosol optical depth (AOD) retrieval products; (2) the CAMS (Copernicus Atmosphere Monitoring Service) reanalysis PM1, PM2.5, and PM10 data; (3) the MERRA-2 (Modern-Era Retrospective analysis for Research and Applications, Version 2) reanalysis PM2.5 data, (4) the OMI (Ozone Monitoring Instrument) tropospheric vertical column density (TVCD) of nitrogen dioxide (NO2), and VCD of sulfur dioxide (SO2) in the Planetary Boundary Layer (PBL), (5) the VIIRS (Visible Infrared Imaging Radiometer Suite) Nighttime Lights data, (6) MODIS Collection 6 Version 2 global monthly fire location data (MCD14ML), (7) population density, (8) MODIS Level 3 Collection 6 land cover types, (9) AERONET (AErosol RObotic NETwork) Version 3 Level 2.0 data, and (10) ground-based PM2.5 concentrations from air quality monitoring stations. Potential Source Contribution Function (PSCF) analyses were performed by integrating with ground-based PM2.5 concentrations and the NOAA (National Oceanic and Atmospheric Administration) HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) air parcel back trajectories to identify potential pollution source areas which are responsible for extreme air pollution in Pakistan. Results show that the ranking of the top polluted cities depends on the type of pollutant considered and the metric used. For example, Jhang, Multan, and Vehari were characterized as the top three polluted cities in Pakistan when considering AquaTerra DTB AOD products; for PM1, PM2.5, and PM10 Lahore, Gujranwala, and Okara were the top three; for tropospheric NO2 VCD Lahore, Rawalpindi, and Islamabad and for PBL SO2 VCD Lahore, Mirpur, and Gujranwala. The results demonstrate that Pakistan’s entire population has been exposed to high PM2.5 concentrations for many years, with a mean annual value of 54.7 μg/cu. m, over all Pakistan from 2003 to 2020. This value exceeds Pakistan’s National Environmental Quality Standards (Pak-NEQS, i.e., <15 μg/cu. m annual mean) for ambient air defined by the Pakistan Environmental Protection Agency (Pak-EPA) as well as the WHO Interim Target-1 (i.e., mean annual PM2.5 <35 μg/cu. m). The spatial analyses of the concentrations of aerosols and trace gases in terms of population density, nighttime lights, land cover types, and fire location data, and the PSCF analysis indicate that Pakistan’s air quality is strongly affected by anthropogenic sources inside of Pakistan, with contributions from surrounding countries. Statistically significant positive (increasing) trends in PM1, PM2.5, PM10, tropospheric NO2 VCD, and SO2 VCD were observed in ~89%, ~67%, ~48%, 91%, and ~88% of the Pakistani cities (80 cities), respectively. This comprehensive analysis of aerosol and trace gas levels, their characteristics in spatio-temporal domains, and their trends over Pakistan, is the first of its kind. Results will be helpful to the Ministry of Climate Change (Government of Pakistan), Pak-EPA, SUPARCO (Pakistan Space and Upper Atmosphere Research Commission), policymakers, and the local research community to mitigate air pollution and its effects on human health.

Muhammad Bilal↗
NASA NTRS1973

Polluted and turbid water masses in Osaka Bay and its vicinity revealed with ERTS-A imageries

ERTS-1 took very valuable MSS imageries of Osaka Bay and its vicinity on October 24, 1972. In the MSS-4 and MSS-5 imageries a complex grey pattern of water masses can be seen. Though some of grey colored patterns seen in black and white prints of the MSS-4 and MSS-5 imageries are easily identified from their shapes as cloud covers or polluted water masses characterized by their color tone in longer wavelengths in the visible region, any correct distribution pattern of polluted or turbid water masses can be hardly detected separately from thin cloud covers in a quick look analysis. In the present investigation, a simple photographic technique was applied using the fact that reflected sun light from cloud including smog and inclined water surfaces of wave have a certain component in the near infrared region, that MSS-7, whereas the light scattered from fine materials suspended in the sea water has nearly no component sensible in MSS-4 and MSS-5 channels.

Watanabe, K.↗
NASA NTRS2002

Effect of 670-nm Light-Emitting Diode Light On Neuronal Cultures

Light close to and within the near infrared range has documented benefits for promoting wound healing in human and animal studies. Our preliminary results using light-emitting diodes (LEDs) in this range have also demonstrated two-to five-fold increases in growth-phase-specific DNA synthesis in normal fibroblasts, muscle cells, osteoblasts, and mucosal epithelial cells in tissue cultures. However, the mechanisms of action of such light on cells are poorly understood. We hypothesized that the therapeutic effects of such light result from the stimulation of cellular events associated with increases in cytochrome oxidase activity. As a first step in testing our hypothesis, we subjected primary neuronal cultures to impulse blockade by tetrodotoxin (TTX), a voltage-dependent sodium channel blocker, and applied LED light at 670 nm to determine if it could partially or fully reverse the reduction of cytochrome oxidase activity by TTX. The wavelength and parameters were previously tested to be beneficial for wound healing.

Wong-Riley, Margaret T. T.↗
NASA NTRS1968

Infrared viewing permits human iris response studies

Infrared image converter tube and a filtered light source monitor and measure the eye of a subject during experimental task-work operations to obtain a more natural measurement of unimpeded iris response. The device permits observation in the near infrared region, with little stimulation to the eye except by normal ambient lighting.

Schnass, E. R.↗
NASA NTRS2019

Fusion of Visible and Thermal-Infrared Imagery for SLAM for Landing on Icy Moons

This paper addresses the problem of localization for landing on the surface of icy moons, like Europa or Enceladus. Due to the possibility of specular reflection as well as high bulk albedo, icy surfaces present new challenges that make traditional vision-based navigation systems relying on visible imagery unreliable. We propose augmenting visible light cameras with a thermal-infrared camera using inverse-depth parameterized monocular EKF-SLAM to address problems arising from the appearance of icy moons. Results were obtained from a novel procedural Europa surface simulation which models the appearance and the thermal properties simultaneously from physically-based methods. In this framework, we show that thermal features improve localization by 23% on average when compared to a visible camera. Moreover, fusing both sensing modalities increases the improvement in localization to 31% on average, compared to using a visible light camera alone.

thermal vision↗
NASA NTRS2007

Plasmonic Antenna Coupling for QWIPs

In a proposed scheme for coupling light into a quantum-well infrared photodetector (QWIP), an antenna or an array of antennas made of a suitable metal would be fabricated on the face of what would otherwise be a standard QWIP. This or any such coupling scheme is required to effect polarization conversion: Light incident perpendicularly to the face is necessarily polarized in the plane of the face, whereas, as a matter of fundamental electrodynamics and related quantum selection rules, light must have a non-zero component of perpendicular polarization in order to be absorbed in the photodetection process. In a prior coupling scheme, gratings in the form of surface corrugations diffract normally gles, thereby imparting some perpendicular polarization. Unfortunately, the corrugation- fabrication process increases the overall nonuniformity of a large QWIP array. The proposed scheme is an alternative to the use of surface corrugations.

Hong, John↗
NASA NTRS1966

Inexpensive infrared source improvised from flashlight

Inexpensive hand-held source of infrared energy is provided by a flashlight bulb coated with a paint which filters out the visible light emitted by the bulb and transmits only infrared radiation. This device can be used for checking infrared sensors and for experimental purposes.

Source record↗
NASA NTRS1988

The near-infrared polarization and color of Comet Halley: What can we learn about the grains

The near infrared polarization and JHK colors of light scattered by dust grains in comet Halley were measured over a wide range in phase angle and heliocentric distance. Colors were redder than solar with no statistically significant variation with phase angle, heliocentric distance, or pre- and post-perihelion. This suggests that the grain population did not change drastically over time and that the data may be combined and modeled. However, short term variations in visible polarization and dust albedo were seen in Halley. Also, near infrared colors became systematically bluer after the observations were completed. The near infrared colors of Halley fall in the range of those of other comets. The near infrared polarization is similar to the visible polarization of Halley and other comets in showing a negative branch at small phase angles and an approximately linear rise toward positive values at larger phase angles. Mie theory calculations and a size distribution based on spacecraft data were used to model the near infrared polarization and color of comet Halley. Numerous lines of evidence point to the presence of dark, absorbing, probably carbonaceous materials in comets.

Brooke, Timothy Y.↗
NASA NTRS2018

The Habitable Exoplanet Observatory (HabEx): Science Goals and Projected Capabilities

Ongoing research, upcoming developments in ground-based facilities, and the launch of new space missions (Transiting Exoplanet Survey Satellite [TESS], James Webb Space Telescope [JWST], and Wide Field Infrared Survey Telescope [WFIRST]) will continue to advance knowledge of the variety and nature of exoplanetary system components over the next decade and a half. However, many key questions will remain: What is the architecture and full diversity of mature planetary systems? What is the linkage between individual planet properties, planetary system architectures, and circumstellar dust structures? How diverse are planetary atmospheres over the full range of planet sizes and stellar insulation levels? Are there Earth-sized planets orbiting in the habitable zone (HZ) of nearby sun-like stars, with water vapor in their atmospheres, evidence for surface oceans and signs of life? Are these really of biotic origin? Answering all of these questions requires direct imaging and spectroscopy from space in reflected light and/or thermal emission. We exclusively discuss reflected light (near ultraviolet [UV] to near infrared [IR]) investigations, identifying some of the observational, technological, and theoretical challenges that must be met to accomplish such a feat. This paper concentrates on one possible implementation strategy and mission concept currently under study: the HabEx (Habitable Exoplanet) Observatory.

Mennesson, Bertrand↗
NASA NTRS2018

Characterizing the Architectures, Diversity and Habitability of Nearby Planetary Systems: The HabEx Observatory

Ongoing research, upcoming developments in ground-based facilities, and the launch of new space missions (Transiting Exoplanet Survey Satellite [TESS], James Webb Space Telescope [JWST], and Wide Field Infrared Survey Telescope [WFIRST]) will continue to advance knowledge of the variety and nature of exoplanetary system components over the next decade and a half. However, many key questions will remain: What is the architecture and full diversity of mature planetary systems? What is the linkage between individual planet properties, planetary system architectures and circumstellar dust structures? How diverse are planetary atmospheres over the full range of planet sizes and stellar insulation levels? Are there Earth-sized planets orbiting in the habitable zone (HZ) of nearby sunlike stars, with water vapor in their atmospheres, evidence for surface oceans and signs of life? Are these signs of life really of biotic origin? Answering all of these questions requires direct imaging and spectroscopy from space in reflected light and/or thermal emission. We exclusively discuss reflected light (near ultraviolet [UV] to near infrared [IR]) investigations, identifying some of the observational, technological, and theoretical challenges that must be met to accomplish such a feat. This paper concentrates on one possible implementation strategy currently under study: the HabEx (Habitable Exoplanet) Observatory mission concept.

Mennesson, B.↗
NASA NTRS2005

Disk-averaged synthetic spectra of Mars

The principal goal of the NASA Terrestrial Planet Finder (TPF) and European Space Agency's Darwin mission concepts is to directly detect and characterize extrasolar terrestrial (Earthsized) planets. This first generation of instruments is expected to provide disk-averaged spectra with modest spectral resolution and signal-to-noise. Here we use a spatially and spectrally resolved model of a Mars-like planet to study the detectability of a planet's surface and atmospheric properties from disk-averaged spectra. We explore the detectability as a function of spectral resolution and wavelength range, for both the proposed visible coronograph (TPFC) and mid-infrared interferometer (TPF-I/Darwin) architectures. At the core of our model is a spectrum-resolving (line-by-line) atmospheric/surface radiative transfer model. This model uses observational data as input to generate a database of spatially resolved synthetic spectra for a range of illumination conditions and viewing geometries. The model was validated against spectra recorded by the Mars Global Surveyor-Thermal Emission Spectrometer and the Mariner 9-Infrared Interferometer Spectrometer. Results presented here include disk-averaged synthetic spectra, light curves, and the spectral variability at visible and mid-infrared wavelengths for Mars as a function of viewing angle, illumination, and season. We also considered the differences in the spectral appearance of an increasingly ice-covered Mars, as a function of spectral resolution, signal-to-noise and integration time for both TPF-C and TPFI/ Darwin.

Mars↗
NASA NTRS1986

Scattered light in the IUE spectra of Epsilon Aurigae

Recent infrared photometry indicates that the alleged disk of particulate matter surrounding the mysterious secondary object in the Epsilon Aur system is cold, around 500 K. IUE spectra, on the other hand, contain significant flux in excess of that expected from an F0 Ia star in the far UV, which if interpreted as a hot secondary star leads to a possible contradiction with the IR data. Other models of the UV excess have been proposed, including the idea that the bulk of the short-wavelength flux is light scattered into the SWP camera from longer wavelengths. With the recent availability of a detailed generalized IUE descattering algorithm it is possible to thoroughly investigate the scattered-light contribution to the short-wavelength continuum. It is found that the IUE spectra are indeed partially contaminated by scattered light, but that even after correction for this instrumental effect a significant time-dependent UV excess is still present.

Altner, B.↗
NASA NTRS2015

NASA Work Experience

I have had the opportunity to support the analytical laboratories in chemical analysis of unknown samples, using Optical Microscopy (OM), Polarizing Light Microscopy (PLM), Fourier-Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEMEDS), and X-ray Powder Diffraction (XPD). I have assisted in characterizing fibers pulled from a spacecraft, a white fibrous residue discovered in a jet refueler truck, brown residue from a plant habitat slated for delivery to the ISS (International Space Station), corrosion on a pipe from a sprinkler, and air filtration material brought back from the ISS. I also conducted my own fiber study in order to practice techniques and further my understanding of background concepts. Furthermore, I had the opportunity to participate in diverse work assignments, where I was assigned to work with other branches of the engineering department for 1-2 days each. The first was in the Materials Science branch where I participated in the construction of the plant habitat intended for use in research aboard the ISS. The second was in the Testing Design branch where I assisted with tensile and hardness testing of over 40 samples. In addition, I have had the privilege to attend multiple tours of the NASA KSC campus, including to the Astronaut Crew Quarters, the VAB (the main area, the Columbia room, and the catwalk), the Visitor Center housing the shuttle Atlantis, the Saturn-V exhibit, the Prototype laboratory, SWAMP WORKS, the Shuttle Landing Facility, the Crawler, and the Booster Fabrication Facility (BFF). Lastly, much of my coursework prepared me for this experience, including numerous laboratory courses with topics diverse as chemistry, physics, and biology.

Florida Tech↗
DOE OSTI2025

Long-lived neutron-star remnants from asymmetric binary neutron star mergers: element formation, kilonova signals and gravitational waves

We present 3D general-relativistic neutrino-radiation hydrodynamics simulations of two asymmetric binary neutron star mergers producing long-lived neutron stars remnants and spanning a fraction of their cooling time scale. The mergers are characterized by significant tidal disruption with neutron rich material forming a massive disc around the remnant. The latter develops one-armed dynamics that is imprinted in the emitted kilo-Hertz gravitational waves. Angular momentum transport to the disc is initially driven by spiral-density waves and enhanced by turbulent viscosity and neutrino heating on longer timescales. The mass outflows are composed by neutron-rich dynamical ejecta of mass ∼10 −3 –10 −2 M ⊙ followed by a persistent spiral-wave/neutrino-driven wind of ≳ 10 −2 M ⊙ with material spanning a wide range of electron fractions, ∼0.1–0.55. Dynamical ejecta (winds) have fast velocity tails up to ∼0.8 (∼0.4) c. The outflows are further evolved to days timescale using 2D ray-by-ray radiation-hydrodynamics simulations that include an online nuclear network. We find complete r-process yields and identify the production of 56 Ni and the subsequent decay chain to 56 Co and 56 Fe. Synthetic kilonova light curves predict an extended (near-) infrared peak a few days postmerger originating from r-process in the neutron-rich/high-opacity ejecta and UV/optical peaks at a few hours (ten minutes) postmerger originating from weak r-process (free-neutron decay) in the faster ejecta components. Additionally, the fast tail of tidal origin generates kilonova afterglows potentially detectable in radio and X band on a few to ten years time scale. Quantitative effects originating from the tidal disruption merger dynamics are reflected in the multimessenger emissions.

abundances↗
NASA NTRS1972

Multispectral determination of vegetative cover in corn crop canopy

The relationship between different amounts of vegetative ground cover and the energy reflected by corn canopies was investigated. Low altitude photography and an airborne multispectral scanner were used to measure this reflected energy. Field plots were laid out, representing four growth stages of corn. Two plot locations were chosen-on a very dark and a very light surface soil. Color and color infrared photographs were taken from a vertical distance of 10 m. Estimates of ground cover were made from these photographs and were related to field measurements of leaf area index. Ground cover could be predicted from leaf area index measurements by a second order equation. Microdensitometry and digitzation of the three separated dye layers of color infrared film showed that the near infrared dye layer is most valuable in ground cover determinations. Computer analysis of the digitized photography provided an accurate method of determining precent ground cover.

Stoner, E. R.↗