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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 145 records · Page 8

Overview of feasibility study on conducting overflight measurements of shaped sonic boom signatures using RPV's

Before beginning this presentation, it is appropriate to acknowledge the sincere interest and financial support provided by the NASA LaRC under contract NAS9-17900. An outline of the material to be used in the present paper is given. It begins with a indication of the origin and objectives of the feasibility study. This is followed by a discussion of various simulation methods of establishing the persistence of shaped sonic boom signatures to large distances including the use of recoverable RPV/drones. The desirable features to be sought out in an RPV along with a rationale for the selection of a 'shaped' sonic boom signature will be addressed. Three candidate vehicles are examined as to their suitability with respect to a number of factors, in particular, modifiability. Area distributions and associated sonic boom signatures of the basic and modified Firebee vehicle will also be shown. An indication of the scope of the proposed wind tunnel and flight test programs will be presented including measurement technologies and predicted waveforms. Finally, some remarks will be made summarizing the study and highlighting the key findings.

Maglieri, Domenic J.↗

Annotated bibliography of Software Engineering Laboratory literature

This document is an annotated bibliography of technical papers, documents, and memorandums produced by or related to the Software Engineering Laboratory. Nearly 200 publications are summarized. These publications cover many areas of software engineering and range from research reports to software documentation. This document has been updated and reorganized substantially since the original version (SEL-82-006, November 1982). All materials have been grouped into eight general subject areas for easy reference: the Software Engineering Laboratory; the Software Engineering Laboratory: software development documents; software tools; software models; software measurement; technology evaluations; Ada technology; and data collection. This document contains an index of these publications classified by individual author.

Morusiewicz, Linda↗

Proceedings of the Eighteenth Annual Software Engineering Workshop

The workshop provided a forum for software practitioners from around the world to exchange information on the measurement, use, and evaluation of software methods, models, and tools. This year, approximately 450 people attended the workshop, which consisted of six sessions on the following topics: the Software Engineering Laboratory, measurement, technology assessment, advanced concepts, process, and software engineering issues in NASA. Three presentations were given in each of the topic areas. The content of those presentations and the research papers detailing the work reported are included in these proceedings. The workshop concluded with a tutorial session on how to start an Experience Factory.

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Coherent Doppler Wind Lidar Technology for Space Based Wind Measurements Including SPARCLE

It has been over 30 years since coherent lidar systems first measured wind velocity, and over 20 years since the "ultimate application" of measuring Earth's winds from space was conceived. Coherent or heterodyne optical detection involves the combination (or mixing) of the returned optical field with a local oscillator (LO) laser's optical field on the optical detector. This detection technique yields the benefits of dramatically improved signal-to-noise ratios; insensitivity to detector noise, background light and multiply scattered light; reduction of the returned signal's dynamic range; and preservation of the optical signal spectrum for electronic and computer processing. (Note that lidar systems are also referred to as optical radar, laser radar, and LADAR systems.) Many individuals, agencies, and countries have pursued the goal of space-based wind measurements through technology development, experiments, field campaigns and studies.

Kavaya, Michael J.↗

Mapping Environmental Contaminants at Ray Mine, AZ

Airborne Visible and InfraRed Imaging Spectrometer (AVIRIS) data was collected over Ray Mine as part of a demonstration project for the Environmental Protection Agency (EPA) through the Advanced Measurement Initiative (AMI). The overall goal of AMI is to accelerate adoption and application of advanced measurement technologies for cost effective environmental monitoring. The site was selected to demonstrate the benefit to EPA in using advanced remote sensing technologies for the detection of environmental contaminants due to the mineral extraction industry. The role of the Jet Propulsion Laboratory in this pilot study is to provide data as well as performing calibration, data analysis, and validation of the AVIRIS results. EPA is also interested in developing protocols that use commercial software to perform such work on other high priority EPA sites. Reflectance retrieval was performed using outputs generated by the MODTRAN radiative transfer model and field spectra collected for the purpose of calibration. We are presenting advanced applications of the ENVI software package using n-Dimensional Partial Unmixing to identify image-derived endmembers that best match target materials reference spectra from multiple spectral libraries. Upon identification of the image endmembers the Mixture Tuned Match Filter algorithm was applied to map the endmembers within each scene. Using this technique it was possible to map four different mineral classes that are associated with mine generated acid waste.

McCubbin, Ian↗

Atmospheric and Spectroscopic Research in the Far Infrared

The University of Oregon (UO) was a participant in a number of far infrared spectroscopic projects over the past three decades. These include Sub-millimeter Infrared Balloon Experiment (SIBEX), the Balloon Intercomparison Campaign (BIC), and the Infrared Balloon Experiment (IBEX). In addition to these field studies, the UO program contained a detector research component and a laboratory spectroscopy element. Through a productive collaboration with Dr. Carli's group in Italy, with Prof. Ade's group in England and with Dr. Chance of Harvard-Smithsonian, we have made substantial contributions to the development of far infrared spectroscopy as a mature measurement technology for the atmospheric science. This report summarizes the activities during the latest grant period, covering the span from February 22, 1998 to February 21, 2002.

Park, Kwangjai↗

NASA's Role in the North American Carbon Program

NASA's participation in the North American Carbon Program will include a significant effort for quantifying terrestrial and adjacent ocean sources and sinks of carbon using a variety of land, ocean, and atmospheric measurements. This effort will require improved remote sensing algorithms, new measurement technologies, refined model parameterizations of carbon cycle processes, advanced satellite data assimilation methodologies, and a data management strategy. NASA's plan for pursuing these activities will be presented. Examples of NASA data management capabilities such as the SeaWiFS on-line field data system will be discussed.

McClain, Charles R.↗

Advanced Measurement Systems Available to PIWG Members

It was developed advanced measurement technologies to meet NASA goals: reduce design cycle time, reduce emission, reduce testing time, increase safety. The technology are saving money. This technology are available now for technology transfer: optical diagnostics, the film technology and MEMS devices.

Anderson, Robert↗

A Head Start to a Healthy Heart

Cambridge Heart, Inc., has licensed the only U.S. Food and Drug Administration-cleared tool to identify those at risk for sudden cardiac death (SCD). The Microvolt T-Wave Alternans Test(TM) was invented by Dr. Richard J. Cohen, a professor at the Harvard-Massachusetts Institute of Technology (MIT) Division of Health Sciences and Technology, with developmental support and funding from NASA's Johnson Space Center and the National Space Biomedical Research Institute (NSBRI) in Houston, Texas. In 1993, MIT licensed the technology to Cambridge Heart, Inc., a start-up company that Dr. Cohen helped to establish. Cambridge Heart's non-invasive technology measures T-wave alternans, a change from one heartbeat to the next that is too minute to be detected by a standard electrocardiogram. Cardiac patients with such a change in heartbeat regulation are faced with a much greater risk of ventricular arrhythmia and SCD than those without it. The company's ability to measure electrical alternans on a microvolt level has been clinically proven to be just as accurate as - and in some studies, more accurate than - more costly and somewhat risky, invasive procedures, such as electrophysiological testing.

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High Tech for Milady's Makeup

"Elizabeth," a computerized beauty analysis system marketed by Elizabeth Arden, is based upon an ARAC data base search of technologies measuring skin profiles. * "Elizabeth" is no longer commercially available.

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Vitamin D Investigation

The solar dosimeter, a spinoff from NASA solar cell technology, measures the amount of solar radiation to which its wearer is exposed. It was used in a University of Cincinnati Medical Center investigation into the effect of sunlight exposure on maintaining vitamin D status in infants. The infants were exposed to sunlight and records were kept by mothers. Each baby wore a solar dosimeter. The two circular "eyes" in the instrument are silicon photovoltaic detectors which collect solar energy, convert it to electric signals and transmit the charge to E-cells that record the charge by plating silver ions onto an electrode. The time required to plate the silver measures the radiation received. The University found the solar dosimeter to be very effective.

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Thermomechanical Response Variability of Stiffened Composite Panels

A significant numerical simulation capability now exists for studying the various phenomena associated with the response, failure, and performance of multilayered composite panels and shells subjected to combined pressure, mechanical, and thermal loads. The phenomena involved cover a wide range of length scales from local to global structural response. The modeling approaches used for multilayered panels include micromechanical models, three-dimensional continuum models, quasi-three-dimensional models, and two-dimensional plate and shell models. Within each category a number of models with several levels of sophistication has evolved. The four categories are described in review papers. Despite the extensive literature cited in the afore-mentioned references, only a few studies have been reported on the effects of stiffness discontinuities, such as those associated with an abrupt stiffener termination or dropped plies, on the response of composite panel. Stiffener termination is often necessary in composite aerospace structures to satisfy detailed design requirements, and therefore an understanding and a prediction of its effect on the response and failure of composite panels are desirable. Such a prediction must take into account the fact that current measurement technology does not allow the accurate determination of the material parameters that are used in the analytical models.

Noor, Ahmed K.↗

Smokestack Monitor

Environmental Protection Agency monitors emissions from industrial smokestacks to obtain such information as how much pollutant material is being discharged into the atmosphere, how rapidly it is being discharged, and how the smoke plume disperses after leaving the stack. Raytheon's invisible laser beam, adapted from NASA's laser doppler technology, measures emission from one of the stacks. Aimed from a van's interior, the beam is projected from the roof mounted scanning pod near the rear of the vehicle. Particles in the smoke coming out of the stack reflect the beam back to light-detecting equipment in the van. The frequency of the returned beam is different from that of outgoing beam; analysis of the difference in frequencies, called "doppler shift" allows determination of the velocity.

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Control of Jet Noise Through Mixing Enhancement

The idea of using mixing enhancement to reduce jet noise is not new. Lobed mixers have been around since shortly after jet noise became a problem. However, these designs were often a post-design fix that rarely was worth its weight and thrust loss from a system perspective. Recent advances in CFD and some inspired concepts involving chevrons have shown how mixing enhancement can be successfully employed in noise reduction by subtle manipulation of the nozzle geometry. At NASA Glenn Research Center, this recent success has provided an opportunity to explore our paradigms of jet noise understanding, prediction, and reduction. Recent advances in turbulence measurement technology for hot jets have also greatly aided our ability to explore the cause and effect relationships of nozzle geometry, plume turbulence, and acoustic far field. By studying the flow and sound fields of jets with various degrees of mixing enhancement and subsequent noise manipulation, we are able to explore our intuition regarding how jets make noise, test our prediction codes, and pursue advanced noise reduction concepts. The paper will cover some of the existing paradigms of jet noise as they relate to mixing enhancement for jet noise reduction, and present experimental and analytical observations that support these paradigms.

Bridges, James↗

Application of Video Image Correlation Techniques to the Space Shuttle External Tank Foam Materials

Results that illustrate the use of a video-image-correlation-based displacement and strain measurement system to assess the effects of material nonuniformities on the behavior of the sprayed-on foam insulation (SOFI) used for the thermal protection system on the Space Shuttle External Tank are presented. Standard structural verification specimens for the SOFI material with and without cracks and subjected to mechanical or thermal loading conditions were tested. Measured full-field displacements and strains are presented for selected loading conditions to illustrate the behavior of the foam and the viability of the measurement technology. The results indicate that significant strain localization can occur in the foam because of material nonuniformities. In particular, elongated cells in the foam can interact with other geometric or material discontinuities in the foam and develop large-magnitude localized strain concentrations that likely initiate failures. Furthermore, some of the results suggest that continuum mechanics and linear elastic fracture mechanics might not adequately represent the physical behavior of the foam, and failure predictions based on homogeneous linear material models are likely to be inadequate.

Hilburger, Mark W.↗

Application of Video Image Correlation Techniques to the Space Shuttle External Tank Foam Materials

Results that illustrate the use of a video-image-correlation-based displacement and strain measurement system to assess the effects of material nonuniformities on the behavior of the sprayed-on foam insulation (SOFI) used for the thermal protection system on the Space Shuttle External Tank are presented. Standard structural verification specimens for the SOFI material with and without cracks and subjected to mechanical or thermal loading conditions were tested. Measured full-field displacements and strains are presented for selected loading conditions to illustrate the behavior of the foam and the viability of the measurement technology. The results indicate that significant strain localization can occur in the foam because of material nonuniformities. In particular, elongated cells in the foam can interact with other geometric or material discontinuities in the foam and develop large-magnitude localized strain concentrations that likely initiate failures. Furthermore, some of the results suggest that continuum mechanics and linear elastic fracture mechanics might not adequately represent the physical behavior of the foam, and failure predictions based on homogeneous linear material models are likely to be inadequate.

Hilburger, Mark W.↗

Combined 2-micron Dial and Doppler Lidar: Application to the Atmosphere of Earth or Mars

A concept is explored for combining the Doppler and DIAL techniques into a single, multifunctional instrument. Wind, CO2 concentration, and aerosol density can all be measured. Technology to build this instrument is described, including the demonstration of a prototype lidar. Applications are described for use in the Earth science. The atmosphere of Mars can also be studied, and results from a recently-developed simulation model of performance in the Martian atmosphere are presented.

Singh, Upendra N.↗

New Millennium Program: Servicing Earth and Space Sciences

NASA has exciting plans for space science and Earth observations during the next decade. A broad range of advanced spacecraft and measurement technologies will be needed to support these plans within the existing budget and schedule constraints.

New Millennium Program Earth Space↗