2,525 research outputs found

    An indicated specular degradation rate for aluminized Mylar surfaces in near-earth orbit from recent photometric observations of the Echo I satellite

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    Photometric measurements of Echo I satellite on specular degradation of aluminized Mylar surface during orbi

    Some Ore Deposits in Maine and The Milan Mine, New Hampshire

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    Some Ore Deposits in Maine and The Milan Mine, New Hampshire by William H. Emmons Department of the Interior, United States Geological Survey - Bulletin 432 Washington, D.C. (1910). Contents: Introduction / Geology / Ore Deposits / Descriptions of Mines / Mines of Hancock County / Mines of Washington County / Mines in Somerset and Oxford Counties / Milan Mine, New Hampshire / Indexhttps://digitalcommons.usm.maine.edu/me_collection/1106/thumbnail.jp

    Photometric measurements of surface characteristics of echo i satellite final report

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    Photometric measurements of Echo I satellite surface characteristic

    Post-processing partitions to identify domains of modularity optimization

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    We introduce the Convex Hull of Admissible Modularity Partitions (CHAMP) algorithm to prune and prioritize different network community structures identified across multiple runs of possibly various computational heuristics. Given a set of partitions, CHAMP identifies the domain of modularity optimization for each partition ---i.e., the parameter-space domain where it has the largest modularity relative to the input set---discarding partitions with empty domains to obtain the subset of partitions that are "admissible" candidate community structures that remain potentially optimal over indicated parameter domains. Importantly, CHAMP can be used for multi-dimensional parameter spaces, such as those for multilayer networks where one includes a resolution parameter and interlayer coupling. Using the results from CHAMP, a user can more appropriately select robust community structures by observing the sizes of domains of optimization and the pairwise comparisons between partitions in the admissible subset. We demonstrate the utility of CHAMP with several example networks. In these examples, CHAMP focuses attention onto pruned subsets of admissible partitions that are 20-to-1785 times smaller than the sets of unique partitions obtained by community detection heuristics that were input into CHAMP.Comment: http://www.mdpi.com/1999-4893/10/3/9

    Large scale flow around turbulent spots

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    Numerical simulations of a model of plane Couette flow focusing on its in-plane spatio-temporal properties are used to study the dynamics of turbulent spots.Comment: 16 pages, 6 figure

    Independent Orbiter Assessment (IOA): Analysis of the orbiter main propulsion system

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    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items (PCIs). To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Orbiter Main Propulsion System (MPS) hardware are documented. The Orbiter MPS consists of two subsystems: the Propellant Management Subsystem (PMS) and the Helium Subsystem. The PMS is a system of manifolds, distribution lines and valves by which the liquid propellants pass from the External Tank (ET) to the Space Shuttle Main Engines (SSMEs) and gaseous propellants pass from the SSMEs to the ET. The Helium Subsystem consists of a series of helium supply tanks and their associated regulators, check valves, distribution lines, and control valves. The Helium Subsystem supplies helium that is used within the SSMEs for inflight purges and provides pressure for actuation of SSME valves during emergency pneumatic shutdowns. The balance of the helium is used to provide pressure to operate the pneumatically actuated valves within the PMS. Each component was evaluated and analyzed for possible failure modes and effects. Criticalities were assigned based on the worst possible effect of each failure mode. Of the 690 failure modes analyzed, 349 were determined to be PCIs
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