12,157 research outputs found

    A 10kW series resonant converter design, transistor characterization, and base-drive optimization

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    Transistors are characterized for use as switches in resonant circuit applications. A base drive circuit to provide the optimal base drive to these transistors under resonant circuit conditions is developed and then used in the design, fabrication and testing of a breadboard, spaceborne type 10 kW series resonant converter

    NOSS Altimeter Detailed Algorithm specifications

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    The details of the algorithms and data sets required for satellite radar altimeter data processing are documented in a form suitable for (1) development of the benchmark software and (2) coding the operational software. The algorithms reported in detail are those established for altimeter processing. The algorithms which required some additional development before documenting for production were only scoped. The algorithms are divided into two levels of processing. The first level converts the data to engineering units and applies corrections for instrument variations. The second level provides geophysical measurements derived from altimeter parameters for oceanographic users

    Inversion algorithms for the microwave remote sensing of soil moisture. Experiments with swept frequency microwaves

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    Two experiments were performed employing swept frequency microwaves for the purpose of investigating the reflectivity from soil volumes containing both discontinuous and continuous changes in subsurface soil moisture content. Discontinuous moisture profiles were artificially created in the laboratory while continuous moisture profiles were induced into the soil of test plots by the environment of an agricultural field. The reflectivity for both the laboratory and field experiments was measured using bi-static reflectometers operated over the frequency ranges of 1.0 to 2.0 GHz and 4.0 to 8.0 GHz. Reflectivity models that considered the discontinuous and continuous moisture profiles within the soil volume were developed and compared with the results of the experiments. This comparison shows good agreement between the smooth surface models and the measurements. In particular the comparison of the smooth surface multi-layer model for continuous moisture profiles and the yield experiment measurements points out the sensitivity of the specular component of the scattered electromagnetic energy to the movement of moisture in the soil

    Code 672 observational science branch computer networks

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    In general, networking increases productivity due to the speed of transmission, easy access to remote computers, ability to share files, and increased availability of peripherals. Two different networks within the Observational Science Branch are described in detail

    On the Optimization of Mixture Resolving Signal Processing Structures

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    Mixture resolving signal processing optimization with optimum linear detection operators and mixture resolving estimator

    NOSS altimeter algorithm specifications

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    A description of all algorithms required for altimeter processing is given. Each description includes title, description, inputs/outputs, general algebraic sequences and data volume. All required input/output data files are described and the computer resources required for the entire altimeter processing system were estimated. The majority of the data processing requirements for any radar altimeter of the Seasat-1 type are scoped. Additions and deletions could be made for the specific altimeter products required by other projects

    Data documentation for the bare soil experiment at the University of Arkansas

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    The reflectivities of several controlled moisture test plots were investigated. These test plots were of a similar soil texture which was clay loam and were prepared to give a desired initial soil moisture and density profile. Measurements were conducted on the plots as the soil water redistributed for both long term and diurnal cycles. These measurements included reflectivity, gravimetric and volumetric soil moisture, soil moisture potential, and soil temperature

    A review of the Shark Bay pearling industry.

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    While there are currently only two pearl culture leases in Shark Bay, two new applications for leases have already been received by the W.A. Fisheries Department. Increased interest is being generated about pearl culture in Shark Bay, which will need to be considered against the background of management plans designed to restrict further entry into other areas, notably the pearly industry of W.A from Exmouth Gulf northwards, and the pearling industry of the Northern Territory. Recent successes with pearl culture in both those areas, and the greatly increased revenues and high lease transfer values realised, must inevitably focus interest on areas of underexploited pearl oysters such as Shark Bay, which appears to have considerable potential for development

    Why Urofsky v. Gilmore Still Fails to Satisfy

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    The United States Court of Appeals for the Fourth Circuit appears to have adopted the rule that any speech uttered by a governmental employee, in the course of performing the work for which the employee was hired, is per se not a matter of public concern. A majority of the court relies on its holdings in DiMeglio v. Haines and Boring v. Buncombe Co. Bd. of Educ. for that proposition. That fact was evident in questioning from the en banc panel of the Fourth Circuit during its rehearing of Urofsky v. Gilmore on October 25, 1999. At issue was the constitutional protection afforded state- employed university faculty when accessing content of a lascivious nature from the Internet via state-owned computers. The Commonwealth of Virginia passed an act in 1996, subsequently amended in 1999, that prohibited such use of state-owned and state-leased computers without prior permission of the employee\u27s agency head. Six state-employed faculty members sued the Commonwealth because the Act chilled their abilities to carry out their dual roles as educators and scholars

    Mars Observer Radar Altimeter Radiometer (MORAR)

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    The Mars Observer Project will permit the advancement of the state of the topographic and hypsometric knowledge of Mars to a level of 10 m or better over the surface of the planet Mars, the measurement of microwave surface brightness temperature of Mars with an accuracy of 15 to 20 K over 24 hours, and the measurement, globally, of surface returned power related to radar cross section with an accuracy of 1 dB and a repeatability of .5 dB. The MORAR Hardware Development, Ground Data Processing, and the Mission Operations will allow the accomplishment of these scientific objectives to define globally the topography of Mars at sufficient vertical resolution and spatial scale to address both large-scale geophysical and small-scale geologic problems, and to obtain global surface electrical and scattering properties of the upper several centimeters of the Martian surface for assessment of the composition, physical state, and volatile distribution of the surface
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