Monday, March 29, 1999 4:00 p.m. Dr. Bart Lipkens Macrosonix Richmond, Virginia http://www.macrosonix.com A new technology called Resonant Macrosonic Synthesis (RMS) has been developed. RMS allows the creation of high amplitude shock-free standing waves in oscillating closed cavities that are driven by a linear motor. Measurements in cavities designed with RMS show standing wave overpressures…
Friday, March 5, 1999 4:00 p.m. Fernando Garcia Osuna Department of Electrical and Computer Engineering The University of Texas at Austin http://www.ece.utexas.edu The key component of any seismic monitoring system is the analog sensor, or transducer. The sensor transforms both strong and weak ground motions into electrical signals, while the remainder of the system is…
Friday, February 26, 1999 4:00 p.m. Dr. F. Levent Degertekin E.L. Ginzton Laboratory Stanford University http://www.stanford.edu/group/ginzton Stanford University Micromachined ultrasonic transducers (MUTs) have become an alternative to piezoelectric transducers in the last few years. They offer solutions to the problems of high frequency medical ultrasonic imaging, which is currently limited by the piezoelectric transducer array…
Friday, February 19, 1999 4:00 p.m. Dr. Al. A. Kolomenskii Department of Physics Texas A&M University Home http://www.tamu.edu A survey of recent studies of the excitation and propagation of surface acoustic waves in solids will be presented. With increasing amplitude, the waveform experiences nonlinear evolution during propagation. Experimental observation and theoretical description of this effect…
Friday, February 12, 1999 4:00 p.m. Dr. Yichi Lu Southwest Texas Research Institute San Antonio, Texas http://www.swri.org The topic of this seminar is Southwest Research Institute’s research and development of magnetostrictive sensors (MsS) and their applications to ultrasonic inspection of industrial components. The MsS technology is a noncontact, inexpensive ultrasonic inspection tool. It generates and…
Friday, February 5, 1999 4:00 p.m. Professor George D. Pollak Section of Neurobiology, School of Biological Sciences The University of Texas at Austin http://www.biosci.utexas.edu In this talk I will address the issue of why there are so many parallel pathways in the ascending auditory system and what functional role they may be playing in audition.…
Friday, January 29, 1999 4:00 p.m. Dr. Robert Hickling University of Mississippi http://home.olemiss.edu/~hickling http://www.olemiss.edu and Professor Richard L. Brown Department of Entomology & Plant Pathology Mississippi State University http://www.msstate.edu/Entomology/Richard.html http://www.msstate.edu/entomology/ENTPLP.html http://www.msstate.edu/ An analysis is presented of acoustic communication by ants, including a study of the black fire ant Solenopsis richteri. Generally, ants’ stridulatory sounds are…
Friday, December 4, 1998 4:00 p.m. Professor Ofodike Ezekoye Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu This seminar will present some of the work done in our group on the effects of acoustic fields on soot production and subsequent growth in combustion systems. First, the aero-thermo-chemical dynamics of soot production in…
Thursday, November 19, 1998 4:00 p.m. Dr. Thomas D. Rossing Department of Physics Northern Illinois University DeKalb, Illinois http://www.physics.niu.edu/fakepages/rossing.htm http://www.physics.niu.edu http://www.niu.edu The modern piano, which is a direct descendant of the harpsichord, has become the most versatile and popular of all musical instruments. In order to explain the production of sound in a piano, we…
Friday, November 6, 1998 4:00 p.m. Joseph B. Gaalaas Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu The accuracy to which human listeners can localize non-impulsive, broadband noise stimuli in a reverberant environment was studied. Physical measurements of the stimuli were obtained with the use of a manikin equipped with a microphone…
Friday, October 30, 1998 4:00 p.m. Professor Yuri Pyl’nov Moscow Institute of Radioengineering Electronics and Automation Moscow, Russia This report is devoted to the first experimental study of nonlinear propagation of phase conjugated ultrasonic beams, carried out in the General Physics Institute (Moscow). Parametric pumping of magnetostrictive ceramics with an alternating magnetic field produces a…
Friday, October 23, 1998 4:00 p.m. Dr. Leonid M. Krutyansky General Physics Institute Russian Academy of Sciences Moscow, Russia This report reviews an investigation of phase conjugation of ultrasonic beams performed in recent years by our group at the General Physics Institute in collaboration with the Moscow Institute of Radio-Engineering Electronics and Automation. A number…
Friday, October 2, 1998 4:00 p.m. Anderson Mills Department of Electrical and Computer Engineering The University of Texas at Austin http://www.ece.utexas.edu The Kirchhoff Integral Theorem can be used to calculate far field quantities from known values on a surface surrounding an acoustic source distribution. Because of interest in predicting the noise generated by turbomachinery, far…
Friday, September 25, 1998 4:00 p.m. Won Suk Ohm Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu When residential areas line both sides of a highway, each side needs a noise barrier. The conventional approach for modeling parallel noise barriers has been mostly based on using the single barrier theory with image…
Friday, September 18, 1998 4:00 p.m. Steven Younghouse Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu Recent experiments with focused ultrasound at frequencies and intensities commonly encountered in biomedical applications have revealed substantial acoustic streaming (dc flow) associated with the formation of shocks. It is the momentum transferred to the fluid due…
Friday, September 4, 1998 4:00 p.m. Professor David Blackstock Department of Mechanical Engineering and Applied Research Laboratories The University of Texas at Austin http://www.me.utexas.edu http://www.arlut.utexas.edu Research is being carried out at the University of Rochester on the effects of intense low frequency underwater sound on mouse lung. A sound pressure level as high as 190…
Friday, May 8, 1998 4:00 p.m. Professor C. L. Morfey Institute of Sound & Vibration Research University of Southampton Southampton, UK http://www.soton.ac.uk More than 80 years ago, Weyl showed that the number of Helmholtz-equation eigenvalues smaller than k2, in a 3D enclosure of arbitrary shape, approaches k3V/6 pin the short-wavelength limit. He also conjectured a…
Friday, May 1, 1998 4:00 p.m. Jeff G. Schmitt Acoustic Systems and Dell Computer Corp. http://www.acousticsystems.com http://www.dell.com Laboratories wishing to make measurements that are traceable to primary national standards must insure that the instruments used to make the measurements are calibrated in a manner that maintains strict traceability to these national primary standards, and they…
Friday, April 24, 1998 4:00 p.m. Paul Calamia Department of Electrical and Computer Engineering The University of Texas at Austin http://www.ece.utexas.edu No abstract available.
Monday, April 13, 1998 4:00 p.m. Penelope Menounou Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu Experimental investigations have shown that noise barrier performance can be improved by making the top edge randomly ragged. A new method termed Directive Line Source Model is presented for predicting the sound field (pressure time waveform)…