Thursday, December 5, 1985 3:30 p.m. C. T. Tindle Applied Research Laboratories on leave from University of Auckland Auckland, New Zealand Exact theoretical descriptions of acoustic propagation in shallow water are restricted to horizontally stratified situations. There are no exact descriptions for propagation over a sloping bottom. Experimental measurements have been made in an indoor…
Thursday , November 14 , 1985 3:30 p.m. Corinne Darvennes Department of Mechanical Engineering The University of Texas at Austin Many noise control problems remain unsolved because the values of the speed of sound in real gases are lacking. In the low pressure limit, the perfect gas approximation can be used. At higher pressures, a good estimate…
Thursday, October 31, 1985 3:30 p.m. James McLean Department of Electrical Engineering The University of Texas at Austin In recent years, the thrust in acoustic horn loudspeaker design has shifted from impedance matching and power transfer to radiation pattern control. Although the two criteria are not completely incompatible with one another, horn designs which satisfy…
Thursday, October 24, 1985 3:30 p.m. Mark F. Hamilton and James A. TenCate Department of Mechanical Engineering The University of Texas at Austin The noncollinear interaction in a rectangular duct of finite amplitude sound waves propagating in higher order modes is investigated both theoretically and experimentally. The theory predicts spatial oscillations in the nonlinearly generated…
Thursday, October 17, 1985 3:30 p.m. Dennis Wilson Mechanical Engineering Department The University of Texas at Austin This research is concerned with a theoretical investigation of intense pressure pulses in water. These pulses are due to the bow and recompression shocks created by a projectile which is fired from an electromagnetic rail gun. The velocities…
Thursday, October 10, 1985 3:30 p.m. David Lindberg Physics Department The University of Texas at Austin Chemical systems display a wide range of behaviors, including periodic and chaotic oscillations. The Belousov-Zhabotinsky reaction, the most studied chemical reaction giving chaos, will be used to present several routes to chaos. Routes to chaos presented will include the…
Thursday, October 3, 1985 3:30 p.m. David A. Nelson Tracoustics Acoustic Systems Austin, Texas The speaker has recently descended from the fog-shrouded mountain citadels of theoretical acoustics to the arid plain of nuts and bolts, brute force “acoustical engineering.” The tension between these two extremes is exemplified in the speaker’s attempts to provide a method,…
Thursday, September 26, 1985 3:30 p.m. Ronald L. Panton Department of Mechanical Engineering The University of Texas at Austin The turbulent flow in a boundary layer can excite acoustic oscillations in a Helmholtz resonator imbedded in the wall. Under certain conditions of timing between the flow and the resonator an extra strong excitation occurs. This…
Tuesday, September 17, 1985 3:30 p.m. Wayne M. Wright Department of Physics Kalamazoo College Kalamazoo, Michigan Thermally generated sound may be significantly enhanced by producing it in an enclosure which has a normal mode at the frequency of interest. A small gas-filled cylindrical container and a line thermal source are used to study the frequency response…
Thursday, September 12, 1985 3:30 p.m. Rick Bailey Department of Electrical Engineering and Applied Research Laboratories The University of Texas at Austin This study represents an inverse problem approach to rough surface acoustical scattering, the objective being to infer certain statistical characteristics of a randomly rough surface directly from the coherently scattered pressure field. Eckart’s physical…
Wednesday, April 24, 1985 12:00 p.m. Professor J.E. White Department of Geophysics Colorado School of Mines For a plane sinusoidal acoustic wave, we know that average intensity is directed perpendicular to the wave front and uniform in magnitude. For two identical plane waves at right angles, intensity must be directed at 45° and be increased…
Wednesday, April 3, 1985 12:00 p.m. “Transient Response of an Electret Microphone” by Whang Cho “A PVDF Touch Sensor for Robotics” by Mark Chang “An Electret Touch Sensor” by Don Veron “Measurements of Harmonics Generated by Finite Amplitude Sound Radiated by a Circular Piston in Water” by Thomas L Riley
Wednesday, March 20, 1985 12:00 p.m. Professor Mark F. Hamilton Department of Mechanical Engineering The University of Texas at Austin Finite amplitude propagation of higher order modes in a rectangular waveguide is analyzed by decomposing the modes into plane waves. Two types of nonlinear interactions may then be considered. The self interaction of an individual…
Wednesday, March 6, 1985 12:00 p.m. C. H. Yew The University of Texas at Austin A method using SH-waves to estimate the quality of an adhesive layer in a bonded plate is discussed in this talk. A mathematical analysis of SH-wave motions in a bonded plate consistent with the experimental arrangement was carried out in…
Wednesday, February 27, 1985 12:00 p.m. A. Bedford ASE-EM Department and Applied Research Laboratories The University of Texas at Austin Although the classical diffusion equation is parabolic, in certain mixture models for the motion of particles in a fluid the equations of motion are hyperbolic and predict a phenomenon that can be called a “diffusion…
Wednesday, February 20, 1985 12:00 p.m. Dan Costley Department of Mechanical Engineering The University of Texas at Austin The Biot-Stoll theory describes the propagation of acoustic waves in a saturated, unconsolidated porous medium. The expressions for the attenuation and phase velocity derived from this theory depend explicitly on the viscosity, density, and bulk modulus of…
Wednesday, February 6, 1985 12:00 p.m. James McClean Department of Electrical Engineering The University of Texas at Austin In 1951, Dr. A. F. Stevenson published a landmark paper in which he put forth a general theory of electromagnetic wave propagation in horns. He also published a companion paper in which he briefly outlined how this…
Wednesday, January 30, 1985 12:00 p.m. Dr. Randall Tagg Research Fellow Department of Physics The University of Texas at Austin Fluid flow between coaxial rotating cylinders presents a problem rich in ways to test our understanding of the dynamics of systems governed by nonlinear equations. A review will be given, from an experimentalist’s point of…
Wednesday, January 16, 1985 12:00 p.m. Alex Garcia Applied Research Laboratories The University of Texas at Austin There are a million stories in that big place they call The University. Some of them are about people making a living from the peculiar way the density of water changes when it is compressed. This is one…
Thursday, December 13, 1984 10:30 p.m. Allan D. Pierce Regent’s Professor School of Mechanical Engineering Georgia Institute of Technology No abstract available.