Measurement of Piezoelectric and Electrostrictive Coefficients of Thin Polymer Films

Wednesday, March 1, 2000 4:00 p.m. Francois Guillot Georgia Institute of Technology Atlanta, Georgia http://www.gatech.edu/ Piezoelectric polymers such as polyvinylidene fluoride (PVDF) and its copolymers are widely used in electromechanical applications such as sonars, actuators and loudspeakers. Their advantages include low manufacturing cost, low density and modulus, and flexible design possibilities. Another type of polymer,…

High-Frequency Acoustics of Ocean Sediments: In-Situ Measurements

Friday, February 25, 2000 4:00 p.m. Dr. Nicholas P. Chotiros Applied Research Laboratories The University of Texas at Austin http://www.arlut.utexas.edu The participation of ARLUT in the sediment acoustics experiment (SAX99) is directed towards determining the underlying physical processes in the penetration of sound into sandy ocean sediments, particularly at shallow grazing angles, and the scattering…

Next Generation Acoustic Transducer Materials: 1-3 Piezocomposite and Beyond

Friday, February 4, 2000 4:00 p.m. Dr. Leslie Bowen Materials Systems, Inc. Littleton, Massachusetts http://www.matsysinc.com 1-3 piezocomposite is a relatively new entry into the piezoelectric materials portfolio of acoustic transducer designers. Originally conceived in the 1970s at Penn State’s Materials Research Laboratory, the material was of limited academic interest until the early 1990s when MSI…

Reconfigurable Arrays for Broadband Feedback Control of Aircraft Fuselage Vibrations

Thursday, January 27, 2000 4:00 p.m. Michael Fripp Massachusetts Institute of Technology Cambridge, Massachusetts http://www.mit.edu Reconfigurable arrays of sensors and actuators can provide robust broadband feedback control with high performance and limited modeling. The weighted summation of the sensor signals identifies the modes that are important to performance and rejects the remaining modes, thus reducing…

The Ocarina: From Pre-Columbian Times to the Legend of Zelda

Friday, December 3, 1999 4:00 p.m. Professor David Peterson Department of Mathematics University of Central Arkansas Conway, Arkansas http://www.uca.edu/divisions/academic/math http://www.uca.edu For thousands of years Indian cultures in the Western hemisphere have produced whistling vessels and musical instruments, ocarinas, from clay. Ocarinas are found in wide array of morphological forms – vegetables, animals, demons, etc. –…

Nonlinear Surface Acoustic Waves in Cubic Crystals

Tuesday, November 23, 1999 4:00 p.m. Ronald E. Kumon Department of Physics The University of Texas at Austin http://www.ph.utexas.edu Both the linear and nonlinear properties of surface waves in crystals are significantly different from those in isotropic media. Recently developed model equations are employed to perform theoretical and numerical studies of nonlinear surface acoustic waves…

Harmonic generation by Rayleigh–Lamb waves in isotropic elastic plates

Friday, November 19, 1999 4:00 p.m. Washington De Lima Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu Harmonic generation by Rayleigh–Lamb waves of finite amplitude in homogeneous, isotropic, stress-free elastic plates is investigated theoretically. A bifrequency primary wave field is considered, in which the two waves propagate in single yet arbitrary Rayleigh–Lamb…

Modern Audio and Acoustic Test and Measurement

Friday, November 12, 1999 4:00 p.m. Dr. Tom Kite Audio Precision Beaverton, Oregon http://audioprecision.com This talk will describe techniques used to measure performance parameters of both analog and digital audio equipment. Particular attention will be given to methods that are also appropriate to acoustic measurements, such as the use of maximum-length sequences (MLS) for pseudo-anechoic…

Automotive Acoustics Applications and Overview with Ford Motor Company

Friday, October 22, 1999 4:00 p.m. Mike Stoeckle Ford Motor Company http://www.ford.com Acoustical considerations play an important role in the design and development of an automobile. The purpose of this discussion is to inform students interested in acoustics of practical applications and the design process in the automotive industry. Emphasis will be on acoustical aspects…

Acoustical Measurements While Drilling

Friday, October 15, 1999 4:00 p.m. Dr. Jean-Pierre Masson and Dr. Kai Hsu Schlumberger Sugarland Product Center Sugarland, Texas http://www.schlumberger.com We present an overview of acoustical measurements while drilling, ranging from low frequency seismic to ultrasonic pulse-echo measurements. The main topic is the development of an acoustical logging-while-drilling (LWD) tool in the kilohertz range. This…

Designing Asphalt Pavement for Improved Acoustical Performance

Friday, October 8, 1999 4:00 p.m. Jeff DeMoss Center for Transportation Research The University of Texas at Austin http://www.utexas.edu/research/ctr Pavement type and surface configuration are known to have a significant effect on traffic noise. Studies of different roadway surfaces have shown that more-porous pavement designs perform better acoustically. However, pavements are currently designed for durability…

Acoustic Emission Testing of Process Industry Equipment

Friday, October 1, 1999 4:00 p.m. Professor Timothy Fowler Department of Civil Engineering The University of Texas at Austin http://www.ce.utexas.edu Acoustic emission serves an important function in the process industries. It is a global nondestructive examination technique which provides a measure of the structural severity of a defect. As such, it is complementary to other…

A Reduced-Noise Gas Flow Design Guide for NASA Glenn Research Center

Friday, September 24, 1999 4:00 p.m. David A. Nelson Nelson Acoustical Engineering, Inc. A “Reduced-Noise Gas Flow Design Guide” has recently been developed for NASA’s John H.Glenn Research Center (GRC) at Lewis Field, Ohio. The purpose of the Guide is to allow GRC engineers and designers to address hearing conservation and community noise issues at…

Piezoelectric PZT Films for Electromechanical Applications

Thursday, June 17, 1999 4:00 p.m. Dr. Qing-Ming Wang Lexmark International, Inc. Lexington, Kentucky http://www.lexmark.com The development of piezoelectric Pb(Ti 0.52 Zr 0.48 )O 3(PZT) thin films toward device miniaturization for microelectromechanical system (MEMS) applications depends largely on the processing capability of PZT film on silicon substrate, since the combination of PZT thin film with…

Magnetostrictive Sensors and Their Applications

Monday, May 17, 1999 4:00 p.m. Dr. Yichi Lu Southwest Texas Research Institute San Antonio, Texas The magnetostrictive sensor is a non-contact, nondestructive inspection technology that is suitable for inspecting ferromagnetic components. Progress has been made in recent years in order to use magnetostrictive sensors for long range pipeline corrosion inspection, suspension bridge cable inspection,…

Algorithm For The Design Of Broadband, Constant-Beamwidth, Point-Element Linear Arrays With Constant Sidelobe Level

Friday, April 9, 1999 4:00 p.m. Joseph B. Gaalaas Department of Mechanical Engineering The University of Texas at Austin http://www.me.utexas.edu An algorithm has been designed that allows one to calculate the individual element weights, as a function of frequency, required to achieve specified values of sidelobe level and half-power beamwidth. The arrays considered have linear…