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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
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

A Laboratory Comparison of a Nephelometer and the Cavity-Attenuated Phase Shift Instrument (CAPS)

The interaction of incoming solar radiation (light) with particulate matter in the atmosphere impacts Earth’s radiation budget and thus is of great importance to climate and climate change. This particulate matter consists of particles, an aerosol referring to the ensemble of these particles. All particles scatter incoming solar radiation, sending some of it back to space and providing a cooling influence on the climate. Some particles additionally absorb incoming solar radiation, causing the particle, and the surrounding atmosphere, to heat, and thus altering atmospheric stability and evaporating water and other substances in the particles, which in turn affect the scattering and absorption of light by the particle.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

Dynamic measurement of bulk modulus of dielectric materials using a microwave phase shift technique

A microwave Doppler shift technique was developed for measuring the dynamic bulk modulus of dielectric materials such as solid propellants. The system has a demonstrated time resolution on the order of milliseconds and a theoretical spatial resolution of a few microns. Accuracy of the technique is dependent on an accurate knowledge of the wavelength of the microwave in the sample being tested. Such measurement techniques are discussed. Preliminary tests with two solid propellants, one non-aluminized and one containing 16% aluminum, yielded reasonable, reproducible results. It was concluded that with refinements the technique holds promise as a practical means for obtaining accurate dynamic bulk modulus data over a variety of transient conditions.

Barker, B. J.↗
NASA NTRS2001

Novel Vertical Interconnects With 180 Degree Phase Shift for Amplifiers, Filters, and Integrated Antennas

In this paper, novel low loss, wide-band coplanar stripline technology for RF/microwave integrated circuits is demonstrated on high resistivity silicon wafer. In particular, the fabrication process for the deposition of spin-on-glass (SOG) as a dielectric layer, the etching of microvias for the vertical interconnects, the design methodology for the multiport circuits and their measured/simulated characteristics are graphically illustrated. The study shows that circuits with very low loss, large bandwidth and compact size are feasible using this technology. This multilayer planar technology has potential to significantly enhance RF/microwave IC performance when combined with semiconductor devices and microelectromechanical systems (MEMS).

Goverdhanam, Kavita↗
NASA NTRS2010

Operation Program for the Spatially Phase-Shifted Digital Speckle Pattern Interferometer - SPS-DSPI

SPS-DSPI software has been revised so that Goddard optical engineers can operate the instrument, instead of data programmers. The user interface has been improved to view the data collected by the SPS-DSPI, with a real-time mode and a play-back mode. The SPS-DSPI has been developed by NASA/GSFC to measure the temperature distortions of the primary-mirror backplane structure for the James Webb Space Telescope. It requires a team of computer specialists to run successfully, because, at the time of this reporting, it just finished the prototype stage. This software improvement will transition the instrument to become available for use by many programs that measure distortion

Blake, Peter N.↗
NASA NTRS1995

Techniques For Topographical Mapping Via Interferometric SAR

Two techniques for processing data acquired by airborne interferometric synthetic-aperture-radar (SAR) system yield terrain-height maps. Predicated on availability of accurate navigational system that yields data on motion and orientation of airplane that carries SAR system and, also effectively gives orientation of baseline between two radar antennas of system. Three-dimensional coordinates of target point on terrain determined from (1) position and orientation of airplane as given by navigational system and (2) slant range gamma and phase shift phase as measured by SAR system.

Madsen, Soren N.↗
NASA NTRS1972

Spectral reflectance of selected aqueous solutions for water quality applications

The relative specular reflectances of individual aqueous solutions having a particular chemical salt content were measured in the 2 to 20 micrometers region of the infrared component or radiant flux. Distilled water was the reflectance standard. The angle of incidence was 70.03 deg plus or minus 0.23 deg. Absolute reflectances of the solutions for the same polarization and angle of incidence were computed by use of the measured relative reflectances, one of the Fresnel equations, and the optical constants of distilled water. Phase shift and phase difference spectra were obtained by respectively applying a Kramers-Kronig dispersion analysis to the absolute and relative reflectance spectra. The optical constants of the solutions were determined by algorithms commonly associated with the Kramers-Kronig analysis. Spectral signatures that qualitatively and quantitatively characterize the solute and that show structure of the infrared bands of water were noted in the phase difference spectra. The relative and absolute reflectances, the phase shift and phase difference spectra and the optical constants are presented in graphical form. Application of these results to remote sensing of the chemical quality of natural waters is discussed briefly.

Querr, M. R.↗