Friday, January 28, 1994 4:00 p.m. Anthony A. Atchley Physics Department Naval Postgraduate School Monterey, CA A single gas bubble, acoustically levitated in a standing wave field and oscillating under the action of that field, can emit a single pulse of blue-white light. This emission, called sonoluminescence (SL), has a number of remarkable features. It…
Friday, January 21, 1994 4:00 p.m. Dr. A. Sarvazyan Rutgers University, New Brunswick, NJ and Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Pushchino, Russia The acoustic nonlinearity parameter B/A of a liquid is a simple function of the pressure derivative of bulk modulus and is directly related to the character of intermolecular…
Friday, December 3, 1993 4:00 p.m. Tom Kite Department of Electrical Engineering The Unviersity of Texas at Austin When driven by a normal power amplifier, a dynamic driver in a sealed enclosure exhibits the frequency response of a resonant, second-order, high-pass filter, and has an underdamped transient response. A power amplifier with negative output impedance…
Friday, November 19, 1993 4:00 p.m. Preston Wilson Applied Research Laboratories and Department of Mechanical Engineering The University of Texas at Austin This presentation describes a new type of underwater sound source, the Combustive Sound Source (CSS). The gas mixture produced by electrolysis of water is captured in a combustion chamber and ignited with a…
Friday, November 12, 1993 4:00 p.m. Jinlong Wu Department of Mechanical Engineering The University of Texas at Austin The subject of this seminar is the propagation of sound in a circular duct with locally reactive acoustical lining, and in which a sheared mean fluid flow exists. Previous theoretical investigations of this problem were based on…
Friday, November 5, 1993 4:00 p.m. Matthew Kaplan Department of Aerospace Engineering and Engineering Mechanics The University of Texas at Austin Computational structural acoustic analysis of submarines can be prohibitively expensive in certain frequency ranges because of the geometric complexity of the structure. A method for dealing with high order finite element models of submarines…
Friday, October 29, 1993 4:00 p.m. Won-Kyu Moon Department of Mechanical Engineering The University of Texas at Austin A finite element equivalent model for the thickness vibrator is formulated. This formulation leads to a new definition of the generalized displacements for a continuous system. The newly defined coordinates are easily interpreted physically and easily used…
Friday, October 22, 1993 4:00 p.m. Ahmed Shaaban Department of Mechanical Engineering The University of Texas at Austin The fracture impedance method is a new technology for estimating the dimension and characteristics of downhole, hydraulically introduced fractures along the wellbore. The method is based on the assumption that the existence of the fracture changes the…
Monday, October 11, 1993 4:00 p.m. Dr. Guan Dinghua Institute of Acoustics Academia Sinica Beijing, China No abstract available.
Friday, October 1, 1993 4:00 p.m. C. L. Morfey Institute of Sound and Vibration Research University of Southampton, UK Results will be presented from recent work on the sound field radiated by the surface vibration of two spheres in an infinite fluid medium. The application originally envisaged was to impact noise of colliding solid spheres,…
Friday, September 24, 1993 4:00 p.m. John T. Post Department of Electrical Engineering The University of Texas at Austin Rayleigh’s Horn Equation and Michalakis A. Averkiou Department of Mechanical Engineering The University of Texas at Austin Measurements of Finite Amplitude Pulses Radiated by Plane Circular Pistons in Water
Friday, September 17, 1993 4:00 p.m. Dr. Vera A. Khokhlova Acoustics Division, Physics Department Moscow State University An overview will be provided of research performed on statistical problems in nonlinear acoustics in the Department of Physics at Moscow State University. Attention will be focused on the propagation of random sound waves containing shocks. A model…
Friday, September 10, 1993 4:00 p.m. Michael Bailey Department of Mechanical Engineering The University of Texas at Austin The violence of gas bubble collapse poses a potential danger in medical ultrasound procedures, and tissues dense gas, such as lung, are among the most sensitive. Developed from predictions of expansion and inertial collapse of bubbles in water,…
Friday, September 3, 1993 4:00 p.m. Members of the Acoustics Faculty Departments of Mechanical Engineering and Electrical Engineering The 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…
Thursday, May 13, 1993 10:00 a.m. Ping-Wah Li Department of Physics The University of Texas at Austin A theoretical investigation of the propagation and absorption of finite-amplitude acoustic waves in media with thermoviscous and multiple relaxation mechanisms will be presented. A nonlinear wave equation, called the generalized Burgers equation, is derived for this purpose. Analytic…
Friday, May 7, 1993 3:30 p.m. Bart Lipkens Mechanical Engineering Department The University of Texas at Austin and Applied Research Laboratories The results of an experimental and numerical study on the propagation of N waves through turbulence is presented. The experiment simulates the propagation of sonic booms through atmospheric turbulence. The N waves are generated…
Friday, April 23, 1993 3:30 p.m. Charles E. Bradley Mechanical Engineering Department The University of Austin at Texas and Applied Research Laboratories In this seminar the results of a theoretical and experimental investigation of the acoustic Bloch waves that occur in a class of periodic waveguides is presented. Many unusual wave phenomena, some known and…
Monday, April 19, 1993 1:00 p.m. Professor Henrik Schmidt Department of Ocean Engineering Massachusetts Institute of Technology No abstract available.
Friday, April 16, 1993 4:00 p.m. James A. Davidson Department of Petroleum Engineering The University of Texas at Austin During the past twenty years, a number of applications for ultrasonic measurement techniques have been developed for the oil industry. This seminar will review many of those developed to provide information useful in gas well drilling…
Friday, April 2, 1993 4:00 p.m. Professor Philip L. Marston Department of Physics Washington State University and Visiting Research Fellow Applied Research Laboratories The average or “radiation” pressure of ultrasound can produce large responses in fluid systems when there is sufficient time for the generally weak second-order forces to act. Examples to be considered include…