27,434 research outputs found

    Structural evaluation of deployable aerodynamic spike booms

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    An extendable boom consisting of a series of telescopic cylindrical tube segments and overlapping lock joints developed for use as an aerodynamic spike mounted atop a missile is described. Two candidate design concepts differing mainly in the particular overlapping lock joint designs are undergoing a combined analytical/experimental evaluation. Some of the results of this evaluation are presented

    An application of interactive computer graphics technology to the design of dispersal mechanisms

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    Interactive computer graphics technology is combined with a general purpose mechanisms computer code to study the operational behavior of three guided bomb dispersal mechanism designs. These studies illustrate the use of computer graphics techniques to discover operational anomalies, to assess the effectiveness of design improvements, to reduce the time and cost of the modeling effort, and to provide the mechanism designer with a visual understanding of the physical operation of such systems

    On Seismic Waves (Third Paper)

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    In two previous papers under the present title 1) 2) the authors have presented data on bodily waves. The present paper contains the corresponding data on surface waves (including seismic sea waves), the magnitude and energy of earthquakes, and miscellaneous topics. The seismograms used were those studied in the previously published investigations; the numbers assigned to individual shocks are as given in the previous papers

    On Seismic Waves (Second Paper)

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    In a first paper under the present title the authors have presented a body of data on travel times. The present paper contains the corresponding data on amplitudes, periods, velocities, etc., for bodily waves. It is intended to present data on surface waves in a third paper

    The Impact of 9/11 and its Aftermath on Substance Use and Psychological Functioning: An Overview

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    This Essay provides a brief summary and evaluation of findings on the mental health and substance abuse consequences of the events of 9/11 throughout the nation and in United States\u27 cities. It also presents new data obtained from clients who entered substance abuse treatment in New York and other cities either before 9/11 or during a six-month period following the events. This Essay discusses how best to interpret these varying research findings. It concludes that crisis produces many responses and most people just coped with 9/11 in their individual ways

    Integrability and Disorder in Mesoscopic Systems: Application to Orbital Magnetism

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    We present a semiclassical theory of weak disorder effects in small structures and apply it to the magnetic response of non-interacting electrons confined in integrable geometries. We discuss the various averaging procedures describing different experimental situations in terms of one- and two-particle Green functions. We demonstrate that the anomalously large zero-field susceptibility characteristic of clean integrable structures is only weakly suppressed by disorder. This damping depends on the ratio of the typical size of the structure with the two characteristic length scales describing the disorder (elastic mean-free-path and correlation length of the potential) in a power-law form for the experimentally relevant parameter region. We establish the comparison with the available experimental data and we extend the study of the interplay between disorder and integrability to finite magnetic fields.Comment: 38 pages, Latex, 7 Postscript figures, 1 table, to appear in Jour. Math. Physics 199

    TRIDENT 1 third stage motor separation system

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    The third stage engine separation system has shown through test and analysis that it can effectively and reliably perform its function. The weight of the hardware associated with this system is well within the targeted value
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