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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 NTRS1989

ISEE/ICE plasma wave data analysis

The work performed for the period 1 Jan. 1985 to 30 Oct. 1989 is presented. The objective was to provide reduction and analysis of data from a scientific instrument designed to study solar wind and plasma wave phenomena on the International Sun Earth Explorer 3 (ISEE-3)/International Cometary Explorer (ICE) missions.

Greenstadt, E. W.↗
NASA NTRS2000

Latitudinal Density Dependence of Magnetic Field Lines Inferred from Polar Plasma Wave Data

Using observations of the electron density, n(sub e), based on measurement of the upper hybrid resonance frequency by the Polar spacecraft Plasma Wave Instrument, we have examined the radial density dependence along field lines in the outer plasmasphere and the near plasmatrough. Sampled L values range from 2.5 to 6.6. Our technique depends on the fact that Polar crosses particular L values at two different points with different radial distance R. In our plasmaspheric data set (n(sub e) > 100/cm3), we find that on average n(sub e) is flat along field lines from the equator up to the latitudes sampled by Polar (R approximately equal to or > 2.0). In the plasmatrough data set (n(sub e) < 100/cm-3), there is on average a mild radial dependence n(sub e) varies as R(exp -1.7).

Goldstein, J.↗
NASA NTRS1994

Geotail MCA plasma wave data analysis

NASA Grant NAG 5-2346 supports the data analysis effort at The University of Iowa for the GEOTAIL Multi-Channel Analyzer (MCA) which is a part of the GEOTAIL Plasma Wave Instrument (PWI). At the beginning of this reporting period we had just begun to receive our GEOTAIL Sirius data on CD-ROMs. Much programming effort went into adapting and refining the data analysis programs to include the CD-ROM inputs. Programs were also developed to display the high-frequency-resolution PWI Sweep Frequency Analyzer (SFA) data and to include in all the various plot products the electron cyclotron frequency derived from the magnitude of the magnetic field extracted from the GEOTAIL Magnetic Field (MGF) data included in the GEOTAIL Sirius data. We also developed programs to use the MGF data residing in the Institute of Space and Astronautical Science (ISAS) GEOTAIL Scientific Data Base (SDB). Our programmers also developed programs and provided technical support for the GEOTAIL data analysis efforts of Co-lnvestigator William W. L. Taylor at Nichols Research Corporation (NRC). At the end of this report we have included brief summaries of the NRC effort and the progress being made.

Anderson, Roger R.↗
DOE OSTI2024

Rupture Model of the 5 April 2024 Tewksbury, New Jersey, Earthquake Based on Regional Lg -Wave Data

On 5 April 2024, an earthquake of magnitude 4.8 occurred in Tewksbury, New Jersey. It was the largest instrumentally recorded event since 1900 in New Jersey and southern New York. Millions of people around New York City, ~65 km east–northeast of Tewksbury, felt the shaking from the mainshock, but the epicentral area experienced no known significant property damages. We determine the focal mechanism, which is oblique faulting, and retrieve the Lg–wave relative source time functions (RSTFs) from the stations at regional distances to understand rupture processes and ground motions. Our fault–slip models well explain azimuthal variations of the RSTFs. The models show the rupture propagating toward the east–northeast (~50° to 60°), not along the fault strike. The slip distribution on the nodal plane striking north and dipping to the east shows a slip area of 1.1 km radius with the rupture propagating down–dip. The down–dip rupture may account for the observed lack of strong shaking in the epicentral area.

58 GEOSCIENCES↗
NASA NTRS1975

Pyroxenes and olivines: Structural implications of shock-wave data for high pressure phases

The nature of the shock-induced, high-pressure phases of olivine and pyroxene rocks is examined in the light of data for the densities of a new class of perovskite-related silicate structures. Also examined are some new Hugoniot and release adiabat data for bronzite. Reexamining available shock data for magnesian pyroxenes and olivines leads to the conclusion that they define a mixed phase (or disequilibrium) region to about the 100 GPa range, related to the kinetics of phase transformation in these silicates. By recognizing this point, certain discrepancies in previous interpretations of shock data can be explained. A set of theoretical Hugonoits for pyroxene and olivine stoichiometry, perovskite-bearing assemblages was constructed based on their properties deduced from high-pressure work, showing that the shock data is compatible with transformations to perovskites in the 45-7GPa region. Finally, the shock data indicate very similar properties for olivine and pyroxene at high pressures making them both equally likely candidates for the lower mantle.

Jeanloz, R.↗
NASA NTRS1997

Archiving of Wideband Plasma Wave Data

Beginning with the third year of funding, we began a more ambitious archiving production effort, minimizing work on new software and concentrating on building representative archives of the missions mentioned above, recognizing that only a small percentage of the data from any one mission can be archived with reasonable effort. We concentrated on data from Dynamics Explorer and ISEE 1, archiving orbits or significant fractions of orbits which attempt to capture the essence of the mission and provide data which will hopefully be sufficient for ongoing and new research as well as to provide a reference to upcoming and current ISTP missions which will not fly in the same regions of space as the older missions and which will not have continuous wideband data. We archived approximately 181 Gigabytes of data, accounting for some 1582 hours of data. Included in these data are all of the AMPTE chemical releases, all of the Spacelab 2/PDP data obtained during the free-flight portion of its mission, as well as significant portions of the S3, DE-1, Imp-6, Hawkeye, Injun 5, and ISEE 1 and 2 data sets. Table 1 summarizes these data. All of the data archived are summarized in gif-formatted images of frequency-time spectrograms which are directly accessible via the internet. Each of the gif files are identified by year, day, and time as described in the Web page. This provides a user with a specific date/time in mind a way of determining very quickly if there is data for the interval in question and, by clicking on the file name, browsing the data. Alternately, a user can browse the data for interesting features and events simply by viewing each of the gif files. When a user finds data of interest, he/she can notify us by email of the time period involved. Based on the user's needs, we can provide data on a convenient medium or by ftp, or we can mount the appropriate data and provide access to our analysis tools via the network. We can even produce products such as plots or spectrograms in hardcopy form based on the specific request of the user.

Kurth, William S.↗
NASA NTRS1994

Nondestructive Characterization of Adhesive Bonds from Guided Wave Data

The critical role played by adhesive bonds in the fracture and failure of composites and other bonded materials is well known. A good knowledge of the mechanical properties of these adhesion joints is a prerequisite to reliable design and reliable prediction of the performance of these bonded structures.

moduli↗
NASA NTRS1994

Nondestructive Characterization of Adhesive Bonds from Guided Wave Data

The critical role played by interface zones in the fracture and failure of composites and other bonded materials is well known. The existing nondestructive evaluation methods are generally not capable of yielding useful quantitative information of the strength of an interface.

developed adhesively bonded joints↗
NASA NTRS2011

Gravitational-Wave Data Analysis with Spinning Merger-Ringdown Waveforms

The recent availability of high-quality, gravitational merger-ringdown waveforms from spinning black-hole systems has made possible the development of multi-mode GW templates for use in data-analysis studies of current and proposed interferometric GW detectors. We report on recent work at NASA Goddard, analyzing the most significant modes from aligned-spin black-hole-binary mergers. From these, we have developed time-domain merger-ringdown GW templates covering the aligned-spin portion of parameter space. We also discuss how using the full information content of aligned-spin mergers can significantly reduce uncertainties in some parameters, emphasizing the significant gains possible in the last stages of merger, inaccessible to inspiral-only post-Newtonian templates.

Kelly Bernard J.↗
NASA NTRS1988

Development of a satellite SAR image spectra and altimeter wave height data assimilation system for ERS-1

The applicability of ERS-1 wind and wave data for wave models was studied using the WAM third generation wave model and SEASAT altimeter, scatterometer and SAR data. A series of global wave hindcasts is made for the surface stress and surface wind fields by assimilation of scatterometer data for the full 96-day SEASAT and also for two wind field analyses for shorter periods by assimilation with the higher resolution ECMWF T63 model and by subjective analysis methods. It is found that wave models respond very sensitively to inconsistencies in wind field analyses and therefore provide a valuable data validation tool. Comparisons between SEASAT SAR image spectra and theoretical SAR spectra derived from the hindcast wave spectra by Monte Carlo simulations yield good overall agreement for 32 cases representing a wide variety of wave conditions. It is concluded that SAR wave imaging is sufficiently well understood to apply SAR image spectra with confidence for wave studies if supported by realistic wave models and theoretical computations of the strongly nonlinear mapping of the wave spectrum into the SAR image spectrum. A closed nonlinear integral expression for this spectral mapping relation is derived which avoids the inherent statistical errors of Monte Carlo computations and may prove to be more efficient numerically.

Hasselmann, Klaus↗