3,892 research outputs found
SPECTRASAT: A concept for the collection of global directional wave spectra
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
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
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
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
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)
Dr. Beal asking Dr. Koch to present a paper on the effects of manipulative treatment on cardiac problems at the NYC AOA convention
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Fabrication of X-Graded H13 and Cu Powder Mix Using High Power Pulsed Nd:YAG Laser
The manufacturing of Functionally Graded Material (FGM) parts using Solid Free Form
manufacturing technologies has been carried out since early 1980. At present, most of the
powder manufacturing techniques are being focused on layering powder with different
powder blend compositions with Z gradients (graded in direction of layer build). Although,
there are a few researchers working on multi powder feeder and deposition system, the study
of laser fusion of the deposited powder (by a powder deposition system) is minimum or not
known to date. Consequently, the manufacturing of functionally graded structures is still
geometry limited. This work was focused on the manufacturing of X-graded (graded along the
powder bed plane) specimens with H13 tool steel and Cu mix. Five bimodal powder blends
were used with a multi-container feed hopper to spread powder layers for the selective laser
fusion of the powder. The powder was fused using a high power Nd:YAG pulsed laser using a
specific scanning strategy to reduce porosity. Specimens were produced with graded Cu
within the H13 matrix. The specimens were analysed for dimensional accuracy,
microstructure, porosity, cracks and micro hardness of the FGM.Mechanical Engineerin
Tracking ocean wave spectrum from SAR images
An end to end algorithm for recovery of ocean wave spectral peaks from Synthetic Aperture Radar (SAR) images is described. Current approaches allow precisions of 1 percent in wave number, and 0.6 deg in direction
McCall v. State, 354 So. 2d 869 (Fla. 1978)
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
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
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