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Full-Text Articles in Physical Sciences and Mathematics
Theory And Estimation Of Acoustic Intensity And Energy Density, Derek C. Thomas
Theory And Estimation Of Acoustic Intensity And Energy Density, Derek C. Thomas
Theses and Dissertations
In order to facilitate the acquisition and accurate interpretation of intensity and energy density data in high-amplitude pressure fields, the expressions for intensity and energy density are examined to ascertain the impact of nonlinear processes on the standard expressions. Measurement techniques for estimating acoustic particle velocity are presented. The finite-difference method is developed in an alternate manner and presented along with bias and confidence estimates. Additionally, two new methods for estimating the local particle velocity are presented. These methods appears to eliminate the errors and bias associated with the finite-difference technique for certain cases.
Acoustical Measurement Of The Human Vocal Tract: Quantifying Speech & Throat-Singing, Bryant R. Foresman
Acoustical Measurement Of The Human Vocal Tract: Quantifying Speech & Throat-Singing, Bryant R. Foresman
Pomona Senior Theses
The field of biological acoustics has witnessed a steady increase in the research into overtone singing, or “throat-singing,” in which a singer utilizes resonance throughout the vocal tract to sing melodies with the overtones created by a vocal drone. Recent research has explored both how a singer vocalizes in order to obtain rich harmonics from a vocal drone, as well as how further manipulations of the vocal apparatus function to filter and amplify selected harmonics. In the field of phonetics, vowel production is quantified by measuring the frequencies of vocal tract resonances, or formants, which a speaker manipulates to voice …
Time Reversal, Brian E. Anderson, Michele Griffa, Paul A. Johnson, Carene Larmat, Timothy J. Ulrich
Time Reversal, Brian E. Anderson, Michele Griffa, Paul A. Johnson, Carene Larmat, Timothy J. Ulrich
Faculty Publications
This article provides an historical overview of Time Reversal (TR), introduces its basic physics, addresses advantages and limitations, and describes some applications of this very active research area of acoustics. In the Geophysics Group at the Los Alamos National Laboratory, we conduct studies of TR of elastic waves in solids. Our work includes application of TR to nondestructive evaluation of materials, as well as to earthquake source characterization, and ground-based nuclear explosion monitoring. We emphasize the term elastic waves here to underscore that we include both compression and shear waves, in contrast to purely acoustic waves that are only compressional.