17,946 research outputs found

    Propagation of sound from aircraft ground operations

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    Atmospheric absorption effects on sound propagation losses during aircraft ground operation

    The propagation of sound from airport ground operations

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    Noise measurements of sound propagation related to jet aircraft takeoff

    Resonances, Unstable Systems and Irreversibility: Matter Meets Mind

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    The fundamental time-reversal invariance of dynamical systems can be broken in various ways. One way is based on the presence of resonances and their interactions giving rise to unstable dynamical systems, leading to well-defined time arrows. Associated with these time arrows are semigroups bearing time orientations. Usually, when time symmetry is broken, two time-oriented semigroups result, one directed toward the future and one directed toward the past. If time-reversed states and evolutions are excluded due to resonances, then the status of these states and their associated backwards-in-time oriented semigroups is open to question. One possible role for these latter states and semigroups is as an abstract representation of mental systems as opposed to material systems. The beginnings of this interpretation will be sketched.Comment: 9 pages. Presented at the CFIF Workshop on TimeAsymmetric Quantum Theory: The Theory of Resonances, 23-26 July 2003, Instituto Superior Tecnico, Lisbon, Portugal; and at the Quantum Structures Association Meeting, 7-22 July 2004, University of Denver. Accepted for publication in the Internation Journal of Theoretical Physic

    Experimental atmospheric absorption values from aircraft flyover noise signals

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    Analysis of aircraft noise recordings to determine experimental values of atmospheric sound absorptio

    Tongues, signs and visions, not God\u27s order for today

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    https://digitalcommons.biola.edu/biola-pubs/1063/thumbnail.jp
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