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Acoustic Spectra from Turbulent Jets
The Journal of the Acoustical Society of America, 1971One of the interesting and important problems involving turbulent jets is that of determining the spectrum of the radiated sound. This has proved to be a difficult theoretical problem because the space-time correlation of the velocity is central in the prediction of such sound characteristics.
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Acoustic phonon power spectra in a periodic superlattice
physica status solidi (b), 2006AbstractWe consider a Green function formalism, based on the frequency distribution, to study the propagation of acoustic phonon modes in a periodic superlattice. The calculations are based on the linear response function approach, which is very convenient to deal with this kind of problem.
P. W. Mauriz +2 more
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Spectra of ion acoustic plasma instability
The Physics of Fluids, 1977An experimental study of ion acoustic plasma turbulence in a collision-dominated positive column is presented. Linear theory predictions, which include ion Landau damping and the effects of a dc electric field, are shown to agree with measured values of convective growth rates.
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Method of invariant manifolds and regularization of acoustic spectra
Transport Theory and Statistical Physics, 1994Abstract A new approach to the problem of reduced description for Boltzmann-type systems is developed. It involves a direct solution of two main problems: thermodynamicity and dynamic invariance of reduced description. A universal construction is introduced, which gives a thermodynamic parameterization of an almost arbitrary approximation.
A. N. Gorban, I. V. Karlin
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Subharmonics Spectra of Acoustics Excitation in Granular Medium
AIP Conference Proceedings, 2008The results of experimental research of specific features of acoustical subharmonics excitation in granular medium are considered. It is founded that signal subharmonics registered at the scale of single granular extremely high varies in time and spectrum of this frequency component lies in some band.
Igor B. Esipov +5 more
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Acoustic measures of lake community size spectra
Canadian Journal of Fisheries and Aquatic Sciences, 2016Acoustic methods were tested as an alternative to catch data to measure size spectra of freshwater fish communities in Lac du Bonnet (LdB), Manitoba, Canada. Eleven daytime hydroacoustic surveys conducted in 2011 and 2012 enabled length-frequency spectra of fish communities to be calculated within LdB.
Laura J. Wheeland, George A. Rose
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Naturally Enhanced Ion-Acoustic Spectra And Their Interpretation
Surveys in Geophysics, 2001Incoherent scatter radars are designed to detect scatter from thermalfluctuations in the ionosphere. These fluctuations contain, among other things,features associated with ion-acoustic waves driven by random motions within theplasma. The resulting spectra are generally broad and noisy, but neverthelessthe technique can, through a detailed analysis of ...
Francis Sedgemore-Schulthess +1 more
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Transient Response Spectra of Coupled Acoustical Resonators
The Journal of the Acoustical Society of America, 1966The maximum absolute pressure magnification of a Helmholtz resonator for an excitation of one cycle of a sine wave is 3.14, occurring when the natural period of the system is equal to the excitation period. When two resonators are coupled together, the response is a function of two uncoupled natural frequencies and a coupling frequency of the system ...
N. N. Reddy, Richard L. Lowery
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Concrete Material Response by Acoustic Spectra Analysis
Journal of the Structural Division, 1976The purpose of the research in this paper was to determine material behavior and strength characteristics of concrete materials, by studying stochastically the random-type acoustic emission patterns and intensities that emanate from concrete during loading.
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Fourth-order cumulants and spectra of acoustic data
The Journal of the Acoustical Society of America, 1992In a recent paper [Dwyer, J. Acoust. Soc. Am. 90, 918–926 (1991)] properties of the Fourier transform of a special case of the fourth-order cumulant were discussed and the results of a transmit–receive experiment presented. The data from this experiment have now been analyzed for more general cases of the fourth-order cumulant and its corresponding ...
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