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Full-Text Articles in Physics
Influence Of Wall Vibrations On The Sound Of Brass Wind Instruments, Wilfried Kausel, Daniel W. Zietlow, Thomas R. Moore
Influence Of Wall Vibrations On The Sound Of Brass Wind Instruments, Wilfried Kausel, Daniel W. Zietlow, Thomas R. Moore
Student-Faculty Collaborative Research Publications
The results of an experimental and theoretical investigation of the influence of wall vibrations on the sound of brass wind instruments are presented. Measurements of the transmission function and input impedance of a trumpet, with the bell both heavily damped and freely vibrating, are shown to be consistent with a theory that assumes that the internal pressure causes an oscillation of the diameter of the pipe enclosing the air column. These effects are shown to be most significant in sections where there are flaring walls, which explains why damping these vibrations in cylindrical pipes normally produces no measurable effects.
Imaging Of Vibrating Objects Using Speckle Subtraction, Thomas R. Moore, Ashley E. Cannaday, Sarah A. Zietlow
Imaging Of Vibrating Objects Using Speckle Subtraction, Thomas R. Moore, Ashley E. Cannaday, Sarah A. Zietlow
Student-Faculty Collaborative Research Publications
A simple method for imaging vibrational motion is proposed. The process consists of capturing two speckled images of a region illuminated by coherent radiation. One of the images is captured before the onset of motion and the other during motion. If the mean speckle intensity is below the threshold for detection or above the saturation intensity of the detector, subtracting the two images produces a high contrast image of the moving region. A theory is shown to agree well with experimental data.