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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
NASA NTRS1991

Failure analysis of the lithium battery: A study of the header deposit on the cell top and diffusion within the electrode glass seal using nuclear microanalysis and FFTIR spectroscopy

The Solid Rocket Booster Range Safety System (SRBRSS) uses a lithium/poly-carbon monofluoride primary battery as a source of electrical power. After cell fabrication and activation, some battery cells have shown self discharge. One possible source of this cell discharge has been suggested to be the formation and growth of a conducting crystallized chemical compound across the glass bead insulator, electrically shorting the glass bead to the casing. This laboratory has begun an analysis of this compound, the glass seal holding the cathode into place, and the cell electrolyte, using Fast Fourier Transform Infrared (FFTIR) Analysis, Rutherford Backscattering Spectroscopy (RBS), and Nuclear Reaction Microanalysis. Preliminary measurements have confirmed the existence of lithium, nitrogen, fluorine, and oxygen on a reddish-brown deposit covering parts of the glass seal holding the positive electrode in place. Cells using Li metal electrodes, have many advantages over conventional primary batteries. One principal disadvantage of using Li batteries on a commercial basis would be the environmental impact of the fluorocarbon material. Another would be the relatively high expense of (CF)n.

Hassan, Razi A.↗
NASA NTRS1984

A theoretical model for the cross spectra between pressure and temperature downstream of a combustor

A theoretical model developed to calculate pressure-temperature cross spectra, pressure spectra, temperature spectra and pressure cross spectra in a ducted combustion system is presented. The model assumes the presence of a fluctuating-volumetric-heat-release-rate disk source and takes into account the spatial distribution of the steady-state volumetric-heat flux. Using the model, pressure, velocity, and temperature perturbation relationships can be obtained. The theoretical results show that, at a given air mass flow rate, the calculated pressure-temperature cross spectra phase angle at the combustor exit depends on the model selected for the steady-state volumetric-heat flux in the combustor. Using measurements of the phase angle, an appropriate source region model was selected. The model calculations are compared with the data. The comparison shows good agreement and indicates that with the use of this model the pressure-temperature cross spectra measurements provide useful information on the physical mechanisms active at the combustion noise source.

Miles, J. H.↗
NASA NTRS2012

Time-Dependent Searches for Point Sources of Neutrinos with the 40-String and 22-String Configurations of IceCube

This paper presents four searches for flaring sources of neutrinos using the IceCube neutrino telescope. For the first time, a search is performed over the entire parameter space of energy, direction and time with sensitivity to neutrino flares lasting between 20 microseconds and a year duration from astrophysical sources. Searches which integrate over time are less sensitive to flares because they are affected by a larger background of atmospheric neutrinos and muons that can be reduced by the use of additional timing information. Flaring sources considered here, such as active galactic nuclei, soft gamma ray repeaters and gamma-ray bursts, are promising candidate neutrino emitters. Two searches are untriggered in the sense that they look for any possible flare in the entire sky and from a predefined catalog of sources from which photon flares have been recorded. The other two searches are triggered by multi-wavelength information on flares from blazars and from a soft gamma-ray repeater. One triggered search uses lightcurves from Fermi-LAT which provides continuous monitoring. A second triggered search uses information where the flux states have been measured only for short periods of time near the flares. The untriggered searches use data taken by 40 strings of IceCube between Apr 5, 2008 and May 20, 2009. The triggered searches also use data taken by the 22-string configuration of IceCube operating between May 31, 2007 and Apr 5, 2008. The results from all four searches are compatible with a fluctuation of the background.

Stamatikos, M.↗
NASA NTRS2012

Time-Dependent Searches for Point Sources of Neutrinos with the 4O-String and 22-String Configurations of IceCube

This paper presents four searches for flaring sources of neutrinos using the IceCube neutrino telescope. For the first time, a search is performed over the entire parameter space of energy, direction, and time with sensitivity to neutrino flares lasting between 20 micro-s and a year duration from astrophysical sources. Searches that integrate over time are less sensitive to flares because they are affected by a larger background of atmospheric neutrinos and muons that can be reduced by the use of additional timing information. Flaring sources considered here, such as active galactic nuclei, soft gamma-ray repeaters, and gamma-ray bursts, are promising candidate neutrino emitters. Two searches are "untriggered" in the sense that they look for any possible flare in the entire sky and from a predefined catalog of sources from which photon flares have been recorded. The other two searches are triggered by multi-wavelength information on flares from blazars and from a soft gamma-ray repeater. One triggered search uses lightcurves from Fermi-LAT which provides continuous monitoring. A second triggered search uses information where the flux states have been measured only for short periods of time near the flares. The untriggered searches use data taken by 40 strings of IceCube between 2008 April 5 and 2009 May 20. The triggered searches also use data taken by the 22-string configuration of IceCube operating between 2007 May 31 and 2008 April 5. The results from all four searches are compatible with a fluctuation of the background.

Abbasi, R.↗
NASA NTRS1997

Activities and Accomplishments of ICAM

A brief historical background on establishing the Institute for Computational and Applied Mechanics (ICAM) is presented and basic goals and objectives are discussed. It is emphasized that the goal of the ICAM has been to develop and maintain a self-sustaining center of excellence in computational methods at Old Dominion University (ODU). Information is provided on funding sources and budget disposition, recent activities and accomplishments, list of graduate students supported on the program, and number of students who received graduate degrees (M.S. as well as Ph.D.). Information is also provided on research coordination with various scientists and engineers, and on different reports specifically written for ICAM. ICAM has been supported, in part, by NASA Langley Research Center through Grant NAG-1-363. This report constitutes the final report for ICAM for the period ending December 1996. The grant has been monitored by the University Affairs Officers at NASA Langley.

Tiwari, S. N.↗
NASA NTRS2005

Technologies for Turbofan Noise Reduction

An overview presentation of NASA's engine noise research since 1992 is given for subsonic commercial aircraft applications. Highlights are included from the Advanced Subsonic Technology (AST) Noise Reduction Program and the Quiet Aircraft Technology (QAT) project with emphasis on engine source noise reduction. Noise reduction goals for 10 EPNdB by 207 and 20 EPNdB by 2022 are reviewed. Fan and jet noise technologies are highlighted from the AST program including higher bypass ratio propulsion, scarf inlets, forward-swept fans, swept/leaned stators, chevron nozzles, noise prediction methods, and active noise control for fans. Source diagnostic tests for fans and jets that have been completed over the past few years are presented showing how new flow measurement methods such as Particle Image Velocimetry (PIV) have played a key role in understanding turbulence, the noise generation process, and how to improve noise prediction methods. Tests focused on source decomposition have helped identify which engine components need further noise reduction. The role of Computational AeroAcoustics (CAA) for fan noise prediction is presented. Advanced noise reduction methods such as Hershel-Quincke tubes and trailing edge blowing for fan noise that are currently being pursued n the QAT program are also presented. Highlights are shown form engine validation and flight demonstrations that were done in the late 1990's with Pratt & Whitney on their PW4098 engine and Honeywell on their TFE-731-60 engine. Finally, future propulsion configurations currently being studied that show promise towards meeting NASA's long term goal of 20 dB noise reduction are shown including a Dual Fan Engine concept on a Blended Wing Body aircraft.

Huff, Dennis↗
NASA NTRS2003

Estimation of the Anthropogenic Influence in the Sahel by Terra and Aqua

Saharan dust impacts the Earth radiation balance. It was suggested that anywhere between 20-50% of the dust is anthropogenic, generated from human activity in the Sahel. Recent study By Prospero et al noticed that most of the sources should be north of Latitude of 15 deg. where population density is small. Here we use Aqua and Terra data to study the dust sources and their possible anthropogenic origin. Dust packages emitted from the Bodele depression and other sources in the southern part of the Sahara, are transported in the winter by a Northern East winds over the Sahel to the ocean. We are tracking these packages with MODIS from their sources to the ocean, showing that most of the dust reaching the Ocean from the Sahelian shore is generated in the Sahara, suggesting that the anthropogenic influence in the area is negligible. Saharan dust was suggested to be the main source of nutrients to the Amazon forest. Here we are also showing that these South Saharan sources around the Bodele depression are very active in the winter and rather passive in the summer, suggesting that the type of dust reaching Brazil, and its mineral content from these sources may be different from the dust that arrives to North America and Europe emitted in the summer from different sources.

Koren, I.↗
NASA NTRS1977

Observations of rapid X-ray flaring from Cygnus X-1

SAS-3 observations of Cyg X-1 in October 1976 show the source to be in a highly active state exhibiting rapid continual flaring on time scales of 1 to 10 s. The flares exhibit temporal structure and variable spectra, but their mean spectrum is similar to that of the source as a whole. The characteristic time scales of the source are 2 to 4 times longer than those previously observed. It is suggested that this active phase of Cyg X-1 signals a modified accretion-disk structure. The flares may result from correlated bunches of the same 'shots ' which are thought to explain the rest of the short-time-scale variability of the source. While the flares superficially resemble X-ray bursts, they are distinct in several respects.

Canizares, C. R.↗
NASA NTRS2002

Chandra X-ray Observations of the Spiral Galaxy M81

A Chandra X-Ray Observatory ACIS-S (Advanced X-ray Astrophysics Facility (Chandra) CCD (Charge Coupled Device) Imaging Spectrometer) imaging observation is used to study the population of X-ray sources in the nearby Sab galaxy M81 (NGC 3031). A total of 177 sources are detected with 124 located within the D25 isophote to a limiting X-ray luminosity of 3e36 ergs/cm(exp 2)/s. Source positions, count rates, luminosities in the 0.3-8.0 keV band, limiting optical magnitudes, and potential counterpart identifications are tabulated. Spectral and timing analysis of the 36 brightest sources are reported including the low luminosity active galactic nucleus, SN 1993J, and the Einstein discovered ultraluminous X-ray source X6.

Swartz, Douglas A.↗
NASA NTRS2021

Swift/UVOT Follow-Up of Gravitational Wave Alerts in the O3 Era

In this paper, we report on the observational performance of the Swift Ultra-violet/Optical Telescope (UVOT) in response to the gravitational wave (GW) alerts announced by the Advanced Laser Interferometer Gravitational Wave Observatory and the Advanced Virgo detector during the O3 period. We provide the observational strategy for follow-up of GW alerts and provide an overview of the processing and analysis of candidate optical/UV sources. For the O3 period, we also provide a statistical overview and report on serendipitous sources discovered by Swift/UVOT. Swift followed 18 GW candidate alerts, with UVOT observing a total of 424 deg2. We found 27 sources that changed in magnitude at the 3σ level compared with archival u- or g-band catalogued values. Swift/UVOT also followed up a further 13 sources reported by other facilities during the O3 period. Using catalogue information, we divided these 40 sources into five initial classifications: 11 candidate active galactic nuclei (AGNs)/quasars, three cataclysmic variables (CVs), nine supernovae, 11 unidentified sources that had archival photometry, and six uncatalogued sources for which no archival photometry was available. We have no strong evidence to identify any of these transients as counterparts to the GW events. The 17 unclassified sources are likely a mix of AGN and a class of fast-evolving transient, and one source may be a CV.

gravitational waves↗
NASA NTRS1981

The Jovian hydrogen bulge - Evidence for co-rotating magnetospheric convection

The Jovian hydrogen bulge is located 180 deg away in the System II longitude from the active sector identified as the source region for Jupiter's decametric radio emission and release of energetic electrons into interplanetary space. The sector results from the large magnetic anomaly in the Jovian northern hemisphere; it is expected that a two-cell magnetospheric convection pattern is found in the Jovian atmosphere. The magnetic anomaly of the active sector produces a convection which brings the magnetospheric plasma to the upper atmosphere at the longitudes below the hydrogen bulge; the hot plasma contains electrons with energies of about 100 keV which dissociate atmospheric molecules into atomic hydrogen creating longitudinal symmetry in hydrogen Lyman alpha emission.

Dessler, A. J.↗
NASA NTRS1987

Comparison of active regions on the nucleus of Comet Halley

The images of the nucleus of Comet Halley returned by the Giotto spacecraft reveal a number of active regions on the surface, one of which is near the expected location of the rotation axis. This feature is larger and brighter than other source regions, suggesting that the mechanism which drives this source is also different. At this active region near the rotation pole the Sun is circumpolar for a significant portion of the solar encounter. Continuous solar insolation causes heating of the nucleus to greater depths and results in the unique properties of this source region. For example, the dust scattering in the antisolar regions around the nucleus is less from the polar region than from the region at the sunward end of the nucleus, consistent with spotty ejection of dusty mantle from the sunward tip and widespread activity in the polar region.

Reitsema, H. J.↗
NASA NTRSDate not supplied

Adaptative Site Management for a 115 Acre Chlorinated Solvent Plume with Two Separate Source Areas at Kennedy Space Center, Florida

Background/Objectives. During Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) activities, Geosyntec delineated a chlorinated volatile organic compound (CVOC) plume at the National Aeronautics and Space Administration’s (NASA’s) Vehicle Assembly Building (VAB) area located at KSC, Florida. The RFI activities identified an approximate 115-acre dissolved plume (primarily vinyl chloride) and a trichloroethene (TCE) source area in an active aerospace complex that is surrounded by sensitive wetland/waterbodies. Due to the size of the impacted area, the Corrective Measure Design included a multi-component strategy: (i) address the source area via bioremediation; (ii) protect sensitive wetlands from impacted groundwater discharge via biosparging; and (iii) Long Term Monitoring (LTM) of the remaining dissolved plume. After the Corrective Measures implementation (CMI), NASA and Geosyntec worked with Florida Department of Environmental Protection (FDEP) to implement an adaptive site management for the complex, 115-acre site outside of the traditional RCRA process. The adaptive site management approach relied on performing supplemental assessments and implementing Interim Measures (IMs) to further assess and implement remedies over time while working within site and budget constraints, with an overall goal of achieving enough mass reduction to transition the entire site to LTM and eventually achieve site closure. Approach/Activities. After the biosparge barrier was operational and bioremediation within the source area (referred to as Hot Spot 1) achieved the Corrective Action Objective (CAO), supplemental assessment of the area between Hot Spot 1 and the biosparge barrier was performed. The conceptual site model was updated using the supplemental assessment results and an air sparge system IM was designed to treat an approximate 1.2 acre area (referred to as Hot Spot 2). After installation of the air sparge system, supplemental assessment within the remainder of the 115-acre dissolved plume was performed and a second TCE source area was identified. The TCE source area and associated areas with elevated CVOC concentrations (referred to as Hot Spot 3) were delineated and a bioremediation IM was implemented. Also, the downgradient impacts from Hot Spot 3 were adjacent to a sensitive waterbody, and negotiations with the FDEP allowed the area to be monitored using LTM. Results/Lessons Learned. The performance of supplemental assessment activities and implementation of remedial alternatives as IMs allowed NASA to successfully address groundwater impacts over time, while working within the FDEP regulatory framework. The implementation of the CMI and multiple IMs has achieved the following goals: (i) the biosparge barrier has mitigated the potential discharge of impacted groundwater to an adjacent wetland; (ii) enhanced bioremediation within Hot Spot 1 achieved the CAO within 2 years and transitioned the area into LTM; (iii) operation of an air sparge system within Hot Spot 2 removed TCE as a constituent of concern and contributed to a reduction (approximately 43%) in the impacted groundwater area outside the air sparge treatment area (plume collapse); and (iv) bioremediation within Hot Spot 3 removed approximately 80% of the CVOC mass and contributed to a reduction (approximately 47%) in the impacted groundwater area outside the bioremediation IM treatment area. Overall, the adaptive approach is protecting the sensitive water bodies surrounding the complex site and reducing the area of impacted groundwater, which is moving the entire site towards LTM.

Rebecca C Daprato↗
NASA NTRS2010

Potentially Habitable Ancient Environments in Gusev Crater, Mars

Habitable environments must sustain liquid water at least intermittently and also provide both chemical building blocks and useful sources of energy for life. Observations by Spirit rover indicate that conditions have probably been too dry to sustain life, at least since the emplacement of the extensive basalts that underlie the plains around the Columbia Memorial Station landing site. Local evidence of relatively minor aqueous alteration [1] probably occurred under conditions where the activity of water was too low to sustain biological processes as we know them. In contrast, multiple bedrock units in West Spur and Husband Hill in the Columbia Hills have been extensively altered. Patterns of elemental abundances are consistent with aqueous processes involving migrating fluids [2]. Fe in several of these units has been extensively oxidized [3]. Conceivably any microbiota present during the aqueous alteration of these rocks might have obtained energy from Fe oxidation. Spirit discovered olivine-rich ultramafic rocks during her descent from Husband Hill southward into Inner Basin. Alteration of similar ultramafic rocks on Earth can yield H2 that can provide both energy and reducing power for microorganisms. Spirit's discovery of deposits rich in ferric sulfate is consistent with the aqueous dissolution and/or alteration of olivine under acidic conditions [2] such as those associated with hydrothermal activity. The oxidation of iron and sulfur that can accompany such activity can be an energy source for life. Hydrothermal systems on Earth that sustain either acidic [4] or neutral to alkaline fluids [5] have been shown to provide this energy. Collectively the observations by Spirit rover are consistent with the possibility that habitable environments existed in Gusev crater at least intermittently in the distant geologic past.

Fe oxidation↗
NASA NTRS2020

ATSA- A Cold, Active Telescope for Space Astronomy

The National Academies’ Decadal Survey telescope studies have produced mission design concepts that plotpathways into the future to follow on from Hubble, Spitzer, JWST and NGRST. Considering the results of theLUVOIR and HabEx studies in particular, it is clear that segmented mirrors will eventually be needed to providevery large apertures in space and that this architecture presents both a scientific opportunity and an engineeringchallenge. Furthermore, while HabEx and LUVOIR cover a great deal of spectrum, both fall short of the mid-IRregion where general astronomy and astrophysics can be undertaken that would be impossible from terrestrialobservatories and where there also exist spectral features of interest in the search for life. A telescope with similarcapabilities to Habex/LUVOIR but also capable of exoplanet work in spectral regions up to 5 µm would largelybridge the gap between those proposals and TPF-I (which would have operated from about 7 µm upwards), andis therefore worthy of study. The Active Telescope for Space Astronomy (ATSA) design study presents a possiblearchitecture and is moderately sized (6 m) to enable the use of both starshade and coronagraph technologies.While the segment gaps of a segmented primary mirror present a challenge for coronagraphy, the architecturedoes allow direct wavefront control at each segment of that mirror, enabling a great degree of control at theprimary source of contrast degradation. While active systems (for example, deformable mirrors on WFIRSTCGI) are being incorporated into telescope designs today, a fully active mirror system needs further developmentfor a future mission. With this concept in mind, and intending to build on the LUVOIR and HabEx studies, wediscuss the elements of a cooled telescope design enabling both general astrophysics and exoplanet studies fromthe near UV through to the near-IR.

Steeves, John↗
NASA NTRS1974

Relation between metric and decametric noise storm sources and microwave S-component emissions

Various activities are reported by taking into account the properties of the active region and its relationship to low frequency burst emissions observed by the IMP-6 satellite. The relation of metric noise continuum storms (200 MHz) with the S-component of microwave emissions (2800 MHz) are examined. Taking the results analyzed, a model on the growth of radio noise continuum sources in metric and decametric frequencies and its relation to microwave and other solar active phenomena are considered.

Sakurai, K.↗
NASA NTRS2004

Oscillatory Hierarchy Controlling Cortical Excitability and Stimulus Integration

Cortical gamma band oscillations have been recorded in sensory cortices of cats and monkeys, and are thought to aid in perceptual binding. Gamma activity has also been recorded in the rat hippocampus and entorhinal cortex, where it has been shown, that field gamma power is modulated at theta frequency. Since the power of gamma activity in the sensory cortices is not constant (gamma-bursts). we decided to examine the relationship between gamma power and the phase of low frequency oscillation in the auditory cortex of the awake macaque. Macaque monkeys were surgically prepared for chronic awake electrophysiological recording. During the time of the experiments. linear array multielectrodes were inserted in area AI to obtain laminar current source density (CSD) and multiunit activity profiles. Instantaneous theta and gamma power and phase was extracted by applying the Morlet wavelet transformation to the CSD. Gamma power was averaged for every 1 degree of low frequency oscillations to calculate power-phase relation. Both gamma and theta-delta power are largest in the supragranular layers. Power modulation of gamma activity is phase locked to spontaneous, as well as stimulus-related local theta and delta field oscillations. Our analysis also revealed that the power of theta oscillations is always largest at a certain phase of delta oscillation. Auditory stimuli produce evoked responses in the theta band (Le., there is pre- to post-stimulus addition of theta power), but there is also indication that stimuli may cause partial phase re-setting of spontaneous delta (and thus also theta and gamma) oscillations. We also show that spontaneous oscillations might play a role in the processing of incoming sensory signals by 'preparing' the cortex.

Shah, A. S.↗
NASA NTRS1989

Newborn stars and stellar winds in Barnard 228

Imaging and spectroscopic observations of premain-sequence stars in the B228 molecular cloud have identified three sites of extended, shock-excited nebulosity. A highly collimated, blueshifted jet is associated with the T Tauri star Sz68 (CoD -33:10685 deg). A candidate Herbig-Haro object is found near Sz68 and the T Tauri star Sz69. A third region of shock-excited nebulosity is identified near the embedded newborn star IRAS 15398-3359. IR excesses observed toward these stellar sources may imply a relationship between outflow activity and the presence of a circumstellar disk. Only one of the two outflow sources with well-defined orientations is aligned with the large-scale, magnetic-field geometry of the cloud in contrast to the global alignment of outflows in the Taurus cloud complex. Data for three previously unidentified emission-line stars are presented. A faint 18th magnitude dMe star located 48 arcsecs west of Sz68 is identified.

Heyer, Mark H.↗