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DOE OSTI2020

Data for Training and Testing Radiation Detection Algorithms in an Urban Environment

The US government routinely performs radiological response deployments to search for the presence of illicit nuclear materials (e.g., highly enriched uranium and weapons-grade plutonium) in a specified area. The deployments can be intelligence driven, in support of law enforcement, and for planned events such as WrestleMania, presidential inaugurations, or political conventions. In a typical deployment, radiation detection systems carried by human operators or mounted on vehicles move in a clearing pattern through the search area. Search teams rely on radiation detection algorithms running on these systems in real time to alert them to the presence of an illicit threat source. The detection and identification of sources is complicated by large variation of natural radiation background throughout a search area and the potential presence of localized non-threat sources such as patients undergoing treatment with medical isotopes. As a result, detection algorithms must be carefully balanced between missing real sources (false negatives) and reporting too many false alarms (false positives).The purpose of this data set is to spur innovations in detecting, identifying, and localizing nuclear materials inurban search missions.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2025

Fe-Coated Optical Fiber for Distributed Corrosion Monitoring in Soil and Aqueous Environment

Natural gas pipeline corrosion represents a substantial cost and safety concern during normal operations. The effective and real-time monitoring of corrosion is important to detect and mitigate pipeline risks before corrosion-related catastrophic events happen. Here, we describe the use of iron (Fe) coated optical fiber sensors (OFS) for distributed corrosion monitoring where Fe acts as a corrosion proxy. By using an optical backscattering reflectometer (OBR), corrosion was monitored based on the increase in the backscattered intensity amplitude of the light being passed as Fe underwent corrosion. The Fe-coated OFSs were prepared with a film thickness between 25–225 nanometers (nm) by an electroless plating approach and corroded by a carbon dioxide (CO2)-saturated acidic electrolyte. The corrosion rate (CR) was approximately 2.5 millimeters (mm)/year for Fe with a film thickness of 30 nm and increased with film thickness. Backscattering-based CRs were supported by visible light transmission measurements, which have been previously demonstrated. Additionally, a correlation between the intermittent transmission and residual Fe film thickness during the corrosion of Fe was established. The corrosion sensor was also tested in soil at > 1 foot depth. Fe-coated OFS was loaded into a Draka cable, which provides mechanical support during fiber deployment and installation into either acidified soil, top-soil, or sandy soil (50/50).

corrosion↗

DOE OSTI2025

Fe-Coated Optical Fiber for Distributed Corrosion Monitoring in Soil and Aqueous Environments

Natural gas pipeline corrosion represents a substantial cost and safety concern during normal operations. The effective and real-time monitoring of corrosion is important to detect and mitigate pipeline risks before corrosion-related catastrophic events happen. Here, we describe the use of iron (Fe) coated optical fiber sensors (OFS) for distributed corrosion monitoring where Fe acts as a corrosion proxy. By using an optical backscattering reflectometer (OBR), corrosion was monitored based on the increase in the backscattered intensity amplitude of the light being passed as Fe underwent corrosion. The Fe-coated OFSs were prepared with a film thickness between 25–225 nanometers (nm) by an electroless plating approach and corroded by a carbon dioxide (CO2)-saturated acidic electrolyte. The corrosion rate (CR) was approximately 2.5 millimeters (mm)/year for Fe with a film thickness of 30 nm and increased with film thickness. Backscattering-based CRs were supported by visible light transmission measurements, which have been previously demonstrated. Additionally, a correlation between the intermittent transmission and residual Fe film thickness during the corrosion of Fe was established. The corrosion was measurable out to > 100 meters (m), which is a significant improvement over our previous work, which showed corrosion sensing at < 10 m. The corrosion sensor was also tested in soil at > 1 foot depth.

corrosion↗

NASA NTRS1974

A cosmic gamma ray burst measured by Apollo 16

A cosmic gamma ray burst at about 1058:21 UT on April 27, 1972, was detected with an omnidirectional scintillation counter on Apollo 16. The event whose energy was approximately 0.0002 erg/sq cm, was pulse height analyzed in 512 channels over the 0.067 less than or equal to E less than or equal to 5 MeV range, and shows a complex, multipeak structure on a 300 msec time scale. The burst was also measured by a collimated X-ray detector on Apollo 16, giving spectral data in the 2 to 8 keV range which, together with a simultaneous observation by Vela 6A, allows a directional determination.

Matteson, J. L.↗

NASA NTRS1975

The Severe Storms Observation Satellite /SSOS/

The objective of the Severe Storms Observation Satellite (SSOS) is to continuously observe meteorological phenomena from geosynchronous altitude and to acquire data whose analysis will lead to a better understanding, early detection, and prediction of severe storms and other significant mesoscale events such as dust storms. Details are discussed as to the Advanced Atmospheric Sounding and Imaging Radiometer designed for SSOS, the use of a special spacecraft for an R&D mission, data acquisition, and data processing and analysis. The required accurate vertical temperature and moisture profiles as well as high temporal and spatial resolution images can best be obtained by a three-axis stabilized system, which offers approximately an order of magnitude sensing improvement over a comparable spinning system due to its capability to continuously view the earth. A block diagram of the severe storm analysis system is included.

Shenk, W. E.↗

NASA NTRS1977

Observations of energetic electrons /E no less than about 200 keV/ in the earth's magnetotail - Plasma sheet and fireball observations

An earlier paper by the authors (1976) has reported on energetic electron anisotropies observed in conjunction with the acceleration regions identified by Frank et al., (1976). The present paper gives more detailed analyses of observations in the distant plasma sheet, including specific features of intensities, energy spectra, and pitch angle distributions of the very energetic electrons associated with intense plasma particle events, with energies ranging between 50 eV and 45 keV, detected with an electron/isotope spectrometer aboard the earth-orbiting spacecraft Imp 8. Two domains are considered: the plasma sheet and the regions near and within the localized magnetotail acceleration regions known as the fireball regions. The instrumentation used offered a number of observational advantages over many previous studies, including inherently low background, large geometric factors, excellent species identification, good angular distribution measurement capability, and availability of high resolution of differential intensities.

Baker, D. N.↗

NASA NTRS1984

A case study illustrating time scales and operational responses for a wind shear episode during the JAWS project

A microburst event on 14 July 1983 illustrates the short time scales involved in responding to this type of wind shear. The event also illustrates how a controller used information from several sources in helping a number of aircraft avoid a dangerous wind shear situation. The implications of this event are discussed for the design of future wind shear detection systems, and these observations are related to data obtained during the JAWS experiment.

Bedard, A. J., Jr.↗

NASA NTRS1986

The heating of the thermal plasma with energetic electrons in small solar flares

The energetic electrons deduced from hard X-rays in the thick target model may be responsible for heating of soft X-ray plasma in solar flares. It is shown from OSO-7 studies that if a cutoff of 10 keV is assumed, the total electron is comparable to the thermal plasma energy. However, (1) the soft X-ray emission often appears to begin before the hard X-ray burst, (2) in about one-third of flares there is no detectable hard X-ray emission, and (3) for most events the energy content (assuming constant density) of soft X-ray plasma continues to rise after the end of the hard X-ray burst. To understand these problems we have analyzed the temporal relationship between soft X-rays and hard X-rays for 20 small events observed by ISEE-3 during 1980. One example is shown. The start of soft X-ray and hard X-ray bursts is defined as the time when the counting rates of the 4.8 to 5. keV and 25.8 to 43.2 keV channels, respectively, exceed the background by one standard deviation.

Lin, H. A.↗

NASA NTRS1989

Cockpit display of hazardous weather information

Information transfer and display issues associated with the dissemination of hazardous-weather warnings are studied in the context of wind-shear alerts. Operational and developmental wind-shear detection systems are briefly reviewed. The July 11, 1988 microburst events observed as part of the Denver TDWR operational evaluation are analyzed in terms of information transfer and the effectiveness of the microburst alerts. Information transfer, message content, and display issues associated with microburst alerts generated from ground-based sources (Doppler radars, LLWAS, and PIREPS) are evaluated by means of pilot opinion surveys and part-task simulator studies.

Hansman, R. John, Jr.↗

NASA NTRS1990

Cockpit display of hazardous weather information

Information transfer and display issues associated with the dissemination of hazardous weather warnings are studied in the context of windshear alerts. Operational and developmental windshear detection systems are briefly reviewed. The July 11, 1988 microburst events observed as part of the Denver Terminal Doppler Weather Radar (TDWR) operational evaluation are analyzed in terms of information transfer and the effectiveness of the microburst alerts. Information transfer, message content and display issues associated with microburst alerts generated from ground based sources are evaluated by means of pilot opinion surveys and part task simulator studies.

Hansman, R. John, Jr.↗

NASA NTRS1991

Cockpit display of hazardous weather information

Information transfer and display issues associated with the dissemination of hazardous weather warnings are studied in the context of wind shear alerts. Operational and developmental wind shear detection systems are briefly reviewed. The July 11, 1988 microburst events observed as part of the Denver Terminal Doppler Weather Radar (TDWR) operational evaluation are analyzed in terms of information transfer and the effectiveness of the microburst alerts. Information transfer, message content and display issues associated with microburst alerts generated from ground based sources (Doppler Radar, Low Level Wind Shear Alert System, and Pilot Reports) are evaluated by means fo pilot opinion surveys and part task simulator studies.

Hansman, R. John, Jr.↗

NASA NTRS1992

Materials SIG quantification and characterization of surface contaminants

When LDEF entered orbit its cleanliness was approximately a MIL-STD-1246B Level 2000C. Its burden of contaminants included particles from every part of its history including a relatively small contribution from the shuttle bay itself. Although this satellite was far from what is normally considered clean in the aerospace industry, contaminating events in orbit and from processing after recovery were easily detected. The molecular contaminants carried into orbit were dwarfed by the heavy deposition of UV polymerized films from outgassing urethane paints and silicone based materials. Impacts by relatively small objects in orbit could create particulate contaminants that easily dominated the particle counts within a centimeter of the impact site. During the recovery activities LDEF was 'sprayed' with a liquid high in organics and water soluble salts. With reentry turbulence, vibration, and gravitational loading particulate contaminants were redistributed about LDEF and the shuttle bay.

Crutcher, E. Russ↗

NASA NTRS1993

Major episodes of geologic change - Correlations, time structure and possible causes

Published data sets of major geologic events of the past about 250 Myr (extinction events, sea-level lows, continental flood-basalt eruptions, mountain-building events, abrupt changes in sea-floor spreading, ocean-anoxic and blackshale events and the largest evaporite deposits) have been synthesized (with estimated errors). These events show evidence for a statistically significant periodic component with an underlying periodicity, formally equal to 26.6 Myr, and a recent maximum, close to the present time. The cycle may not be strictly periodic, but a periodicity of about 30 Myr is robust to probable errors in dating of the geologic events. The intervals of geologic change seem to involve jumps in sea-floor spreading associated with episodic continental rifting, volcanism, enhanced orogeny, global sea-level changes and fluctuations in climate. The period may represent a purely internal earth-pulsation, but evidence of planetesimal impacts at several extinction boundaries, and a possible underlying cycle of 28-36 Myr in crater ages, suggests that highly energetic impacts may be affecting global tectonics. A cyclic increase in the flux of planetesimals might result from the passage of the Solar System through the central plane of the Milky Way Galaxy - an event with a periodicity and mean phasing similar to that detected in the geologic changes.

Rampino, Michael R.↗

NASA NTRS1994

Plate mode velocities in graphite/epoxy plates

Measurements of the velocities of the extensional and flexural plate modes were made along three directions of propagation in four graphite/epoxy composite plates. The acoustic signals were generated by simulated acoustic emission events (pencil lead breaks or Hsu-Neilson sources) and detected by by broadband ultrasonic transducers. The first arrival of the extensional plate mode, which is nondispersive at low frequencies, was measured at a number of different distances from the source along the propagation direction of interest. The velocity was determined by plotting the distance versus arrival time and computing its slope. Because of the large dispersion of the flexural mode, a Fourier phase velocity technique was used to characterize this mode. The velocity was measured up to a frequency of 160 kHz. Theoretical predictions of the velocities of these modes were also made and compared with experimental observations. Classical plate theory yields good agreement with the measured extensional velocities. For predictions of the dispersion of the flexural mode, Mindlin plates theory, which includes the effects of shear deformation and rotatory inertia was shown to give better agreement with the experimental measurements.

Prosser, W. H.↗

NASA NTRS1995

Results from GROCSE I: A real-time search for gamma ray burst optical counterparts

The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE 1 has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still emitting gamma rays. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given.

Lee, B.↗

NASA NTRS1999

Does UV CETI Suffer from the Mad Syndrome?

Photometric data have been analyzed and searched for events of flaring and other variability. Some flaring has been detected, though probably not at a level that will hinder our continuing spectral analysis. X-ray diagnostics for the very hot coronal emission measure are under investigation in order to determine whether or not the very hot coronal plasma contributes significantly to the observed X-ray flux in the (EUV) Extreme Ultraviolet Radiation. The key test of the MAD syndrome lies in whether or not the coronal lines indicate a depletion in metals in the corona relative to the underlying photosphere.

Drake, Jeremy↗

NASA NTRS1999

Does UV CETI Suffer from the MAD Syndrome?

Photometric data have been analysed and searched for events of flaring and other variability. Some flaring has been detected, though probably not at a level that will hinder our continuing spectral analysis. X-ray diagnostics for the very hot coronal emission measure are under investigation in order to determine whether or not the very hot coronal plasma contributes significantly to the observed X-ray flux in the EUV. The key test of the MAD syndrome lies in whether or not the coronal lines indicate a depletion in met- als in the corona relative to the underlying photosphere. While some progress has been made in this direction, not as much work has been accomplished as expected due to the increasing commitments of the PI to the CXO project as it nears launch. A no-cost extension has been granted in order to further the analysis and carry out the next stages of the investigation: to construct an emission measure distribution with which to compute a synthetic continuum to compare with the observed continuum.

Drake, Jeremy↗

NASA NTRS1998

Evolution of the 1997-98 El Nino and La Nina: the Role of Altimetry in ENSO Studies and Prediction

El Nino and the Southern Oscillation (ENSO) are known to be a quasi-periodic coupled ocean-atmosphere phenomenon occurring roughly every 3-7 years. Its largest oceanic manifestations are found in the equatorial Pacific, but it is of global climatic significance. During the flight of the TOPEX]Poseidon altimeter, the equatorial Pacific was in the midst of an unusual period of prolonged ENSO warming in the mid-1990's. In 1997, the tropical Pacific witnessed the development of a major El Nino event, rivaling in strength the 1982-83 El Nino. The intensity of this El Nino, and its rapid intensification early in the calendar year, caught the scientific community by surprise. None of the forecast models, statistical or dynamical, captured these features of the 1997 El Nino, although those models that assimilated in situ ocean observations did better than most in predicting that the event would occur in 1997. The onset of the El Nino coincided with the occurrence of several westerly wind events in the western Pacific rather than to delayed oscillator physics. However, western Pacific sea levels were anomalously elevated a year and a half prior to the onset, which may have helped precondition the system to a particularly strong ENSO episode. The coming of La Nina was foreshadowed by large-scale drops in sea level in the western tropical Pacific and cyclonic wind stress curl anomalies far beyond the +\- 8 degrees latitude bounds of the TAO mooring array. In past El Nino events, the evolution of the coupled system could only be studied from the perspective of in situ observations. The 1997-1998 El Nino event will be the first time a major El Nino event will have been observed from start to finish via remotely-sensed measurements of sea surface topography, sea surface temperature, sea surface winds, ocean color, and precipitation. These observations have considerable potential for advancing coupled climate forecasts on time scales from seasons to decades. This presentation will address questions along the lines of: (1) What are the scientific problems in ENSO that can benefit most from altimetry data? (2) Are there any precursors in the global ocean-atmosphere system for the 1997-98 extreme event? (3) Is there a unique role of altimetry in detecting potential precursors?(4) Has Topex/Poseidon data been adequately used to improve ENSO forecasts? Is there any firm evidence? (6) What is the status of the transition of El Nino into a La Nina?

Busalacchi, Antonio J.↗