OF THE DISSERTATION Comparison of Conventional and Bayesian Analysis for the Ultrasonic Characterization of Cancellous Bone by Amber Mae Groopman Doctor of Philosophy in Physics Washington University in St. Louis, 2014 Professor James G. Miller, Chair This dissertation investigates the physics underlying the propagation of ultrasonic waves in cancellous bone. Although quantitative ultrasound ha...

[1] Desert booming can be heard after a natural slumping event or during a sand avalanche generated by humans sliding down the slip face of a large dune. The sound is remarkable because it is composed of one dominant audible frequency (70 to 105 Hz) plus several higher harmonics. This study challenges earlier reports that the dunes’ frequency is a function of average grain size by demonstrating...

Albite (NaAlSi3O8) is an aluminosilicate mineral. Its crystal structure consists of 3-D framework of Al and Si tetrahedral units. We have used Density Functional Theory to investigate the high-pressure behavior of the crystal structure and how it affects the elasticity of albite. Our results indicate elastic softening between 6-8 GPa. This is observed in all the individual elastic stiffness com...

Three-dimensional compressionaland shear-wave velocity (“Vp” and “Vs,” respectively) structure is obtained for the SE Geysers geothermal area from microearthquake arrival-time data. The results indicate a region of high Vp and high Vs in the northwest portion of the area studied, and a low value of VpNs at depths corresponding to the upper part of the steam reservoir. The Vp and Vs anomalies ar...

The interpretation of simultaneous ionospheric Doppler sounding and ground magnetometer observations of low-latitude Pi2 waves is revised. We compare the theoretical estimates of the ionospheric Doppler velocity for the same amplitude of the ground magnetic disturbances produced by a large-scale compressional mode and an Alfvén mode. The plasma vertical displacement caused by the wave electric ...

An inhomogeneous cosmological magnetic field will create Alfvén-wave modes that induce a small rotational velocity perturbation on the last scattering surface of the microwave background radiation. The Alfvén-wave mode survives Silk damping on much smaller scales than the compressional modes. This, in combination with its rotational nature, ensures that there will be no sharp cut-off in anisotr...

An anomalous body with low Vp (compressional wave velocity), low Vs (shear wave velocity), and high Vp/Vs anomalies is observed at 8–11 km depth beneath the upper east rift zone of Kilauea volcano in Hawaii by simultaneous inversion of seismic velocity structure and earthquake locations. We interpret this body to be a crustal magma reservoir beneath the volcanic pile, similar to those widely re...

The dispersion behavior of circumferential creeping waves around a fluid-filled cylindrical cavity in an infinite elastic medium is analyzed by computational methods. Phase and group velocity as well as attenuation curves are constructed by numerically solving the dispersion equation. A comparison of the corresponding modes for elastic and rigid hosts is presented. The modes in both cases exhib...