10,527 research outputs found

    Simple models for the shuttle remote manipulator system

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    The investigation is aimed at establishing a series of simple models which can be used to study the forces and moments which occur due to the reaction control system (RCS) jet plume firings during a deployment or retrieval of an IUS type payload. The models considered in this investigation are primarily planar in nature. In this study primary attention is given to the roles the payload play in determining the overall moments on the remote manipulator system arm

    Removal of apple trees

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    Strong Shift Equivalence of C∗C^*-correspondences

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    We define a notion of strong shift equivalence for C∗C^*-correspondences and show that strong shift equivalent C∗C^*-correspondences have strongly Morita equivalent Cuntz-Pimsner algebras. Our analysis extends the fact that strong shift equivalent square matrices with non-negative integer entries give stably isomorphic Cuntz-Krieger algebras.Comment: 26 pages. Final version to appear in Israel Journal of Mathematic

    Analysis of aircraft microwave measurements of the ocean surface

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    A data system was developed to process, from calibrated brightness temperature to computation of estimated parameters, the microwave measurements obtained by the NASA CV-990 aircraft during the 1972 Meteorological Expedition. A primary objective of the study was the implementation of an integrated software system at the computing facility of NASA/GSFC, and its application to the 1972 data. A single test case involving measurements away from and over a heavy rain cell was chosen to examine the effect of clouds upon the ability to infer ocean surface parameters. The results indicate substantial agreement with those of the theoretical study; namely, that the values obtained for the surface properties are consistent with available ground-truth information, and are reproducible except within the heaviest portions of the rain cell, at which nonlinear (or saturation) effects become apparent. Finally, it is seen that uncorrected instrumental effects introduce systematic errors which may limit the accuracy of the method

    Survey Simulations of a New Near-Earth Asteroid Detection System

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    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth-Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes >=140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of new large-format 10 um detector arrays capable of operating at ~35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline suitable for operating on the trial cadence. We tested this pipeline on a simulated sky populated with astrophysical sources such as stars and galaxies extrapolated from Spitzer and WISE data, the catalog of known minor planets (including Main Belt asteroids, comets, Jovian Trojans, etc.), and the synthetic NEA model. Trial orbits were computed for simulated position-time pairs extracted from the synthetic surveys to verify that the tested cadence would result in orbits suitable for recovering objects at a later time. Our results indicate that the Earth-Sun L1 and Venus-trailing surveys achieve similar levels of integral completeness for potentially hazardous asteroids larger than 140 m; placing the telescope in an interior orbit does not yield an improvement in discovery rates. This work serves as a necessary first step for the detailed planning of a next-generation NEA survey.Comment: AJ accepted; corrected typ

    Kennesaw State University - Maintenance Optimization and Cost Analysis

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    The Department of Housing and Residence Life was looking for ways to improve the quality of their work while saving costs at the same time. The department allowed the team to look over their work orders where the team noticed over 50% of the work orders were related to room turnover. After this discovery, the team focused all efforts on room turnover and went over the process in detail with management. The team asked to see the standard operating procedure for room turnover and learned that most of the staff did not know they had one. The team wanted to investigate why the staff was not aware of the SOP, so the team met with the assistant director of housing facilities to discuss why the SOP was not in use. He expressed that the SOP was not specific enough to direct the technicians in what the department was looking for. This led the team to begin thinking about creating a new SOP. After some research, the team learned that reducing variability was a good way of saving costs and that standard operating procedures were a reliable way of reducing variability. The team spoke with the department and reached the decision that a new SOP was the right decision for the department. The team began by shadowing the technicians to learn how the procedure should be done and where improvements could be made. As the team shadowed, they learned that resident assistants were supposed to be performing the inspections. This inspired the team to continue with creating the SOP but to also fully shift inspection duties to the resident assistants. After discussions with the housing department management, the new SOP created by the team was accepted and the trial runs with resident directors performing the inspections began. The team recommended that the department make the new SOP available to all resident and student assistants to ensure that each inspection was done in the same manner to reduce variability and rework
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