Friday, September 22, 1995 4:00 p.m. Dr. David P. Knobles The Applied Research Laboratories The University of Texas at Austin Modeling acoustic propagation in shallow water and/or littoral ocean environments is a difficult problem in present day computational ocean acoustics. Unlike deep water propagation, the propagation of sound in shallow water waveguides is usually characterized…
Detection Using Biocorrelations Friday, September 15, 1995 4:00 p.m. Dr. Melvin J. Hinich Mike Hogg Professor of Local Government Consider the problem of detecting an unknown waveform in additive noise. The waveform may be unknown due to changes in a known waveform used in active radar or sonar, or it may be a waveform used…
Friday, September 8, 1995 4:00 p.m. B. J. Landsberger Department of Mechanical Engineering University of Texas at Austin Similar to a beam of light, underwater ultrasonic beams can be very directive. Also similar to light, an ultrasonic beam will undergo diffraction as it propagates and refraction as it encounters an interface of two media. For…
Friday, September 1, 1995 4:00 p.m. Members of the Acoustics Faculty Departments of Mechanical Engineering and Electrical Engineering University of Texas at Austin The purpose of this seminar is to introduce members of the acoustics faculty and their research associates to anyone who is either new at UT or simply curious. Overviews of current projects…
Oblique Reflection of Shock Waves in a Slow Sound Speed Fluorocarbon Liquid Tuesday, June 13, 1995 4:00 p.m. Bruce J. P. Mortimer School of Electrical Engineering Cape Technikon Cape Town, South Africa Fluorocarbon liquids have very low sound speed. In addition, because the equation of state of these fluids is highly nonlinear, the nonlinearity parameter…
Friday, May 5, 1995 4:00 p.m. James Bulgrin Brooke Army Medical Center, Fort Sam Houston, TX and Hughes Aircraft Corp., Fullerton, CA During the past thirty years there have been few advances in the development of automated heart sound analysis. The slow advancement is in part due to the inability of conventional spectral analysis techniques…
Nonlinear Elastic Behavior of Granular Porous Media Friday, April 28, 1995 4:00 p.m. Dr. Mukul Sharma Department of Petroleum Engineering University of Texas at Austin For most rocks, the elastic moduli obtained from ultrasonic measurements, well logs and static stress cycling measurements indicate that Εultrasonic > Εlog >> Εstatic. Stress-strain diagrams demonstrate that the sampled…
Friday, April 21, 1995 4:00 p.m. Dr. Jack Sheehan Applied Research Labs, The University of Texas at Austin Automotive customers tend to identify quiet with quality. Vehicles which eliminate engine, transmission, final drive, tire, road, and wind noise from the passenger compartment command a premium in the marketplace compared to otherwise similar competitors. It is…
Wednesday, April 12, 1995 3:00 p.m. Dr. Rodney Whitaker Los Alamos National Laboratory Los Alamos National Laboratory has had a program in long range, low frequency atmospheric acoustics, for the last several years. This work began as part of the Laboratory’s research in arms control and verification under the sponsorship of the Department of Energy.…
Friday, April 7, 1995 4:00 p.m. Steve Ho Mechanical Engineering Department University of Texas at Austin In normal design the top edge of a noise barrier is straight. As a result, noise diffracted from the barrier edge seems to come from a string of highly correlated point sources, that is, a straight line source. The…
Friday, March 24, 1995 4:00 p.m. Dr. Joe Thornhill Applied Research Labs University of Texas at Austin Wavelet transforms are a relatively new member of a family of mathematical techniques referred to as time-frequency and time-scale techniques. Wavelets have found application in many fields including down hole oil well drilling, vibration, speech, video, electrocardiology and…
Thursday, March 9, 1995 9:00 a.m. Robin O. Cleveland Applied Research Labs and Department of Mechanical Engineering, University of Texas at Austin The United States is considering the development of a new supersonic passenger aircraft. Of some concern is the annoyance of the sonic boom generated by the aircraft to observers on the ground. We…
Friday, Feb. 24, 1995 4:00 p.m. Dr. Linda Thibodeau and Dr. Craig Champlin Program in Communication Sciences and Disorders We will provide an overview of the various applications in acoustics that are being undertaken in the Program in Communication Sciences and Disorders. The general areas that will be covered include academic coursework and both basic…
Friday, February 10, 1995 4:00 p.m. Dr. J. D. Gavenda Department of Physics University of Texas at Austin Ultrasonic waves are strongly absorbed by the conduction of electrons in pure metals at low temperatures. An applied magnetic field can induce resonant absorption of the ultrasound with accompanying changes in the sound velocity. A brief review…
Friday, January 27, 1995 4:00 p.m. Geoffrey S. Royal Applied Research Labs University of Texas at Austin A broadband coupled-mode model analysis of acoustic propagation in a shallow-water wedge-shaped environment is presented. Simulated time series from a coupled mode model calculation are compared to measured time series taken during a tank experiment conducted by Tindle…
Friday, January 20, 1995 4:00 p.m. Dr. Evan K. Westwood Applied Research Labs University of Texas at Austin A normal mode model has been developed for underwater acoustic propagation in an ocean having a multi-layered elastic bottom. Following a brief tutorial on normal mode theory and the effects of shear waves, a description of the…
Wednesday, November 23, 1994 3:30 p.m. Wonkyu Moon “Thermodynamic property considerations for modeling piezoelectric ceramic vibrators including thermal effects” Wonkyu Moon “Bond graph model for one-dimensional heat conduction for modeling of piezoelectric ceramic vibrators including thermal effects” Oleg Rudenko “Analytical method for describing the paraxial region of finite amplitude sound beams” Vera Khokhlova “Modification of…
Monday, November 21, 1994 3:30 p.m. Mike Bailey “Bioeffects of positive and negative pulses in vivo” Robin Cleveland “Sonic Boom Risetime” Mark Hamilton “Transient axial solution for the reflection of a spherical wave from a paraboloidal mirror” Larry Gelin “Experimental study of reflection of airborn, spark-produced N waves by a paraboloidal dish” Tom Kite “The…
Saturday and Sunday, November 19-20, 1994 Professor Oleg V. Rudenko Chair, Acoustics Faculty Department of Physics, Moscow State University The two lectures on Saturday will be an introductory short course on the general properties and special features of nonlinear acoustic wave interactions in media with weak and strong dispersion. Both spectral and temporal analyses will…
Friday, November 18, 1994 4:00 p.m. Katya Knight “Extensions of the theory for nonlinear Rayleigh waves” Katya Knight “Pulsed nonlinear Rayleigh waves” Zhenya Zabolotskaya “Evolution equations for nonlinear Rayleigh wave propagation” Doug Meegan “Theoretical model for nonlinear Stoneley and Scholte waves”