A MESSAGE TO THE GATEWAY
The following sections on acoustics provide the scientific fundamentals and a description of the physiology of the human ear. In addition, the final sections of this series supplies the student an introduction to ultrasonic sound, which is being increasingly used in medical diagnostics and therapies. The instructor carries the option of rearranging the material to fit the needs and the presumed mathematical maturity of the class. Excerpts are available online at this site, the remainder may be requested through Gateway Central. Some portions of the mathematical derivations may be skipped in order to make the course easier (but a bit less rigorous). Much of the material contained herein refers to the forth coming text The Science and Applications of Acoustics written by D. R. Raichel and used in republication format in the acoustics courses taught by the author.
The first part describes the importance of acoustics to the bioengineer and the physician, with some overview of biomedical applications. The second part defines sound, describes salient features of acoustic signals and the wave nature of sound. The third section derives the acoustical wave equation (we eschewed the popular spring and weight exposition as not being truly analogous). The following section is devoted to the physiology of the human ear and psychoacoustics.
Ultrasonics constitute the main topic of a separate treatment, with emphasis on the differences from audio-range acoustics, particularly the occurrence of relaxation phenomena. Because of the rather sophisticated mathematics entailed in theoretical treatment of ultrasonics, that might be beyond the ken of the typical undergraduate, we have concentrated on the applications without delving into mathematical and physical details.
This region of study cannot be deemed complete without supplementing the student's experience with laboratory work and design projects. A very important aspect of experimentation (and testing) is the use of real time spectrum analysis, not only as a tool to assay the signals generated but also to evaluate the effect of transmission (or non-transmission) through specific media, e.g. simple fluids, solid materials, biomaterials, etc. Many of the techniques and theories underlying the evaluation of acoustical signals are also used in X-rays, magnetic resonance procedures, and image analyses. The student who fully understands the fundamentals of acoustics is well equipped to deal with other wave phenomena.
Move forward to an OVERVIEW OF ACOUSTICS AND ITS APPLICATIONS IN MEDICAL FIELDS
Support for the development of this module was provided by the National Science Foundation and The Cooper Union for the Advancement of Science and Art.
Please send questions or comments to Professor Ron Adrezin or Professor Daniel Raichel.