3,892 research outputs found

    SPECTRASAT: A concept for the collection of global directional wave spectra

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    The synthetic aperture radar (SAR) imagery from SEASAT revealed a rich tapestry of backscatter patterns from the surface of the ocean. Although still far from being fully understood, these patterns occurred on nearly all spatial scales accessible to the SAR, that is from its spatial resolution of 25 m to its full swath width of 100 km. Futhermore, the backscatter signature appear to reveal a large variety of atmospheric and oceanic processes that occur above, at, and below the ocean surface. Proper interpretation of these signatures of varying scales with respect to their underlying geophysical causes is a major objective of SAR ocean research. Even now, however, it is clear that SAR offers a unique means to monitor wind and waves over global scales. A properly designed, configured, and complimented orbiting SAR system should yield substantial improvements in operational forecasts vital to marine activities. Since wind and wave information is optimally extracted in the spectral domain, the name SPECTRASAT is proposed for this global collection scheme

    Operational wave forecasting with spaceborne SAR: Prospects and pitfalls

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    Measurements collected in the Shuttle Imaging Radar (SIR-B) Extreme Waves Experiment confirm the ability of Synthetic Aperture Radar (SAR) to yield useful estimates of wave directional energy spectra over global scales, at least for shuttle altitudes. However, azimuth fall-off effects tend to become severe for wavelengths shorter than about 100 m in most sea states. Moreover, the azimuth fall-off problem becomes increasingly severe as the platform altitude increases beyond 300 km. The most viable solution to the global wave measurements problem may be a low altitude spacecraft containing a combination of both the SAR and the Radar Ocean Wave Spectrometry (ROWS). Such a combination could have a synergy which yield global spectral estimates superior to those of either instrument singly employed

    A significant post-launch calibration experiment for the SEASAT-A SAR

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    A technique for periodically monitoring the impulse response function of the SEASAT-A synthetic aperture radar is outlined that yields most of the significant contributors to the overall instrument transfer function. The essential measurement involves exciting the total SAR system at L-band with a strong point source scatterer, receiving via the normal S-band analog data link, and finally sampling and processing only a small subset of data in the immediate vicinity of the strong point source

    Vol. 25, No. 2

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    Contents: Survey of Recent Legislation Affecting Police Officers and Firefighters, by Bruce C. Beal Recent Developments Further References, compiled by Yoo-Seong Songhttps://scholarship.kentlaw.iit.edu/iperr/1042/thumbnail.jp

    Vol. 25, No. 2

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    Contents: Survey of Recent Legislation Affecting Police Officers and Firefighters, by Bruce C. Beal Recent Developments Further References, compiled by Yoo-Seong Songhttps://scholarship.kentlaw.iit.edu/iperr/1042/thumbnail.jp

    Invitation from Dr. Beal to Dr. Koch for the 60th Annual AOA Convention (NYC)

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    Dr. Beal asking Dr. Koch to present a paper on the effects of manipulative treatment on cardiac problems at the NYC AOA convention

    McCall v. State, 354 So. 2d 869 (Fla. 1978)

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    Constitutional Law-THE FINE LINE BETWEEN PROTECTED AND NON-PROTECTED SPEEC

    The Seasat SAR Wind and Ocean Wave Monitoring Capabilities: A case study for pass 1339m

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    A well organized low energy 11 sec. swell system off the East Coast of the U.S. was detected with the Seasat Synthetic Aperture Radar and successfully tracked from deep water, across the continental shelf, and into shallow water. In addition, a less organized 7 sec. system was tentatively identified in the imagery. Both systems were independently confirmed with simultaneous wave spectral measurements from a research pier, aircraft laser profilometer data, and Fleet Numerical Spectral Ocean Wave Models

    Study and assessment of advanced ETC/LSS application to space shuttle

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    A variety of advanced life support components and subsystems are evaluated to determine their potential application to the space shuttle and related vehicles

    Dissimilar Electron Beam Welding of Nickel Base Alloy 625 and 9% Cr Steel

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    AbstractTo improve the thermal efficiency of fossil running power plants increasing the live steam temperature is essential. In power plant construction, 9-12% chromium martensitic steels are widely used but if steam temperatures rise above 625°C there is no way around nickel base alloys.The scope of this study was to ascertain the weldability of cast nickel base alloy 625 with cast martensitic 9% chromium steel COST CB2, using electron beam welding (EBW). Similar (A625/A625) and dissimilar joint welding experiments on 50mm thick plates were executed. Microstructure of welded joints was investigated and mechanical-technological tests were carried out.Results show that work pieces were completely welded and the microstructure of the seam shows no problems except some δ-ferrite grains near the fusion line on the CB2 side. The joints exhibit good mechanical properties in spite of the presence of a thin layer with very high hardness in the heat affected zone (HAZ) on the CB2 steel side. [1]
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