2,211 research outputs found
Panel 21 Enhancing the Stature of the IS Field
At the AIS’95 conference, many were inspired by Tom Davenport’s keynote address. Tom lamented that when things happen in the real world about which IS researchers could provide learned insight based on over thirty years of research, the media rarely calls upon us to comment
Application of Fiber Optic Instrumentation
Fiber optic sensing technology has emerged in recent years offering tremendous advantages over conventional aircraft instrumentation systems. The advantages of fiber optic sensors over their conventional counterparts are well established; they are lighter, smaller, and can provide enormous numbers of measurements at a fraction of the total sensor weight. After a brief overview of conventional and fiber-optic sensing technology, this paper presents an overview of the research that has been conducted at NASA Dryden Flight Research Center in recent years to advance this promising new technology. Research and development areas include system and algorithm development, sensor characterization and attachment, and real-time experimentally-derived parameter monitoring for ground- and flight-based applications. The vision of fiber optic smart structure technology is presented and its potential benefits to aerospace vehicles throughout the lifecycle, from preliminary design to final retirement, are presented
Photometry using the Infrared Array Camera on the Spitzer Space Telescope
We present several corrections for point source photometry to be applied to
data from the Infrared Array Camera (IRAC) on the Spitzer Space Telescope.
These corrections are necessary because of characteristics of the IRAC arrays
and optics and the way the instrument is calibrated in-flight. When these
corrections are applied, it is possible to achieve a ~2% relative photometric
accuracy for sources of adequate signal to noise in an IRAC image.Comment: 16 pages, 13 figures. Accepted for publication in the Publications of
the Astronomical Society of the Pacifi
Advanced Fiber Optic-Based Sensing Technology for Unmanned Aircraft Systems
This presentation provides an overview of fiber optic sensing technology development activities performed at NASA Dryden in support of Unmanned Aircraft Systems. Examples of current and previous work are presented in the following categories: algorithm development, system development, instrumentation installation, ground R&D, and flight testing. Examples of current research and development activities are provided
Silicon based substrate with yttrium silicate environmental/thermal barrier layer
A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a yttrium silicate
Silicon based substrate with environmental/ thermal barrier layer
A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a barium-strontium alumino silicate
Silicon based substrate with calcium aluminosilicate environmental/thermal barrier layer
A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a calcium alumino silicate
Silicon based substrate with calcium aluminosilicate/thermal barrier layer
A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a calcium alumino silicate
Probabilities of Large Earthquakes in the San Francisco Bay Region, California
In 1987 a Working Group on California Earthquake Probabilities was organized by the U.S. Geological
Survey at the recommendation of the National Earthquake Prediction Evaluation Council (NEPEC). The
membership included representatives from private industry, academia, and the U.S. Geological Survey. The
Working Group computed long-term probabilities of earthquakes along the major faults of the San Andreas
fault system on the basis of consensus interpretations of information then available. Faults considered by the
Working Group included the San Andreas fault proper, the San Jacinto and Imperial-faults of southern
California, and the Hayward fault of northern California. The Working Group issued a final report of its
findings in 1988 (Working Group, 1988) that was reviewed and endorsed by NEPEC.
As a consequence of the magnitude 7.1 Loma Prieta, California, earthquake of October 17, 1989, a
second Working Group on California Earthquake Probabilities was organized under the auspices of NEPEC.
Its charge was to review and, as necessary, revise the findings of the 1988 report on the probability of large
earthquakes in the San Francisco Bay region. In particular, the Working Group was requested to examine the
probabilities of large earthquakes in the context of new interpretations or physical changes resulting from the
Loma Prieta earthquake. In addition, it was to consider new information pertaining to the San Andreas and other
faults in the region obtained subsequent to the release of the 1988 report. Insofar as modified techniques and
improved data have been used in this study, the same approach might also, of course, modify the probabilities
for southern California. This reevaluation has, however, been specifically limited to the San Francisco Bay
region.
This report is intended to summarize the collective knowledge and judgments of a diverse group of
earthquake scientists to assist in formulation of rational earthquake policies. A considerable body of information
about active faults in the San Francisco Bay region leads to the conclusion that major earthquakes are likely
within the next tens of years. Several techniques can be used to compute probabilities of future earthquakes,
although there are uncertainties about the validity of specific assumptions or models that must be made when
applying these techniques. The body of this report describes the data and detailed assumptions that lead to
specific probabilities for different fault segments. Additional data and future advances in our understanding of
earthquake physics may alter the way that these probabilities are estimated. Even though this uncertainty must
be acknowledged, we emphasize that the findings of this report are supported by other lines of argument and
are consistent with our best understanding of the likelihood for the occurrence of earthquakes in the San
Francisco Bay region
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