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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Focusing Of High-Amplitude Sound Waves Using The Time Reversal Process, Brian D. Patchett
Focusing Of High-Amplitude Sound Waves Using The Time Reversal Process, Brian D. Patchett
Theses and Dissertations
Time reversal is a method often used to focus sound to a desired location, and works best in a reverberant environment. The effect of focus location within a reverberant environment is presented first, revealing that proximity to reflecting surfaces has a significant effect on the amplitude of the focus both experimentally and when using a modal summation model. These effects are a primary component to creating focus signals at high amplitudes. High-amplitude focusing experiments show that when multiple sources are used simultaneously to generate a focus, a peak amplitude pressure spike of 200 dB can be achieved in air. A …
Coupled Oscillators: Protein And Acoustics, Angelique N. Mcfarlane
Coupled Oscillators: Protein And Acoustics, Angelique N. Mcfarlane
Theses
This work encompassed three different vibrational energy transfer studies of coupled resonators (metal, topological, and microtubule comparison) inspired by the lattices of microtubules from regular and cancerous cells. COMSOL Multiphysics 5.4 was utilized to design the experiment. The simulation starts with an acoustic pressure study to examine the vibrational modes present in coupled cylinders, representing α-, β-tubulin heterodimers. The Metal Study consisted of 3 models (monomer, dimer, and trimer) to choose the correct height (40 mm) and mode (Mode 1) for study. The Topological Study was run to predict and understand how the lattice structure changes over a parametric sweep …
Considerations For And Development Of Sound Level Maps For The M16a4 Rifle, Reese D. Rasband
Considerations For And Development Of Sound Level Maps For The M16a4 Rifle, Reese D. Rasband
Theses and Dissertations
Small firearms can create sound levels exceeding the safe threshold of human hearing with even one shot. Understanding how the sound propagates will lead to better range and military drill design. This thesis describes errors associated with different predictive interpolation models for the M16A4. Before directly discussing potential sources of error, the thesis first seeks to validate the data acquired. This is done through waveform inspection with a focus on shot-to-shot consistency. Finding the standard deviation in level between a 10-shot volley provides a good baseline with which other sources of error can be compared to. For both peak and …
Volcano Infrasound: Progress And Future Directions, Jacob F. Anderson, Jeffrey B. Johnson
Volcano Infrasound: Progress And Future Directions, Jacob F. Anderson, Jeffrey B. Johnson
Geosciences Faculty Publications and Presentations
Over the past two decades (2000–2020), volcano infrasound (acoustic waves with frequencies less than 20 Hz propagating in the atmosphere) has evolved from an area of academic research to a useful monitoring tool. As a result, infrasound is routinely used by volcano observatories around the world to detect, locate, and characterize volcanic activity. It is particularly useful in confirming subaerial activity and monitoring remote eruptions, and it has shown promise in forecasting paroxysmal activity at open-vent systems. Fundamental research on volcano infrasound is providing substantial new insights on eruption dynamics and volcanic processes and will continue to do so over …