4,099 research outputs found

    A rugged electron/ion source for spacecraft charging experiments

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    A simple, novel technique was developed for generating a large-diameter, uniform electron beam with appropriate current density for spacecraft charging studies

    Development of a continuous broad-energy-spectrum electron source

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    The development of a practical prototype, large-area, continuous-spectrum, multienergy electron source to simulate the lower energy (approx = 1 to 30 keV) portion of the geosynchronous orbit electron environment was investigated. The results of future materials-charging tests using this multienergy source should significantly improve the understanding of actual in-orbit charging processes and should help to resolve some of the descrepancies between predicted and observed spacecraft materials performance

    Laboratory studies of spacecraft response to transient discharge pulses

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    The in-orbit measurement of spacecraft discharge properties was investigated. The experiments include design and fabrication of appropriate sensors and effects of spacecraft electromagnetic responses on the interpretation of the discharge data. Electric field sensors especially designed to response to high-speed transient signals were installed on a mock-up of a satellite. The simple mock-up was basically a sheet of aluminum rolled to form a cylinder. A movable spark-discharge noise source designed to be electromagnetically isolated from its power supply system was used to induce transient signals at various locations on the spacecraft's outer surface. The measurements and their implications are described. It is concluded that practical orbital measurements to define discharge noise source properties should be possible, and that simple mock-ups of the type described below are useful in sensor system design and data interpretation

    Transient response measurements on a satellite system

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    A set of instruments designed to detect the occurance of electrical breakdown was flown on a synchronous-orbit satellite. The LeRC sensors were installed on cables inside the vehicle. Accordingly, they respond to signals coupled into the satellite wiring system. The SRI sensors were located on the exterior of the vehicle and detected the RF noise pulses associated with surface breakdowns. The results of the earlier SRI program are being used to design and develop a set of intrumentation suitable for inclusion as a general piggy-back package for the detection of the onset of satellite charging and breakdowns on synchronous orbit satellites

    Asymptotically Stationary and Static Space-times and Shear-free Null Geodesic Congruences

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    In classical electromagnetic theory, one formally defines the complex dipole moment (the electric plus 'i' magnetic dipole) and then computes (and defines) the complex center of charge by transforming to a complex frame where the complex dipole moment vanishes. Analogously in asymptotically flat space-times it has been shown that one can determine the complex center of mass by transforming the complex gravitational dipole (mass dipole plus 'i' angular momentum) (via an asymptotic tetrad trasnformation) to a frame where the complex dipole vanishes. We apply this procedure to such space-times which are asymptotically stationary or static, and observe that the calculations can be performed exactly, without any use of the approximation schemes which must be employed in general. In particular, we are able to exactly calculate complex center of mass and charge world-lines for such space-times, and - as a special case - when these two complex world-lines coincide, we recover the Dirac value of the gyromagnetic ratio.Comment: 11 page

    Patent Reexamination

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    Overview of International Arbitration in the Intellectual Property Context

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    Resolving intellectual property rights (“IPR”) issues through alternative dispute resolution (“ADR”) proceedings was a technique long-developing in many major countries. Despite the earlier presence of the Arbitration Act in United States law, the subject of use of arbitration in IPR situations, especially regarding U.S. patents, remained an open and contested issue, until the original addition of 35 U.S.C. § 294 to the U.S. Patent Act in 1982. U.S. law is now resolved in the availability of IPR arbitration as an ADR tool, either through a “pre-problem” contract, such as a license, or as a “post-problem” mechanism elected and/or established by agreement. There are basics that underlie use of arbitration generally, which are also primary in IPR situations

    Patent Reexamination

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