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variable that combines the effects of frequency and temperaturę. In view of the fact that all dynamie measuring techniques cannot be rei labie over a broad rangę of frequencies and temperatures, a temperature-frequency equivalence is not only valuable but necessary for extrapolating data into regions in which the direct measurement of dynamie properties is either difficult or impossible. Because a variety of measurement techniques, instrumenta-tion, and damping materials exist. the need for apply-ing a temperature*frequency equivalence (in the form of a reduced temperaturę nomogram) is impera-tive. The author of this report, who is certainly aware of the use of the reduced temperaturę nomogram, has chosen to include plots of frequency- and tern* perature-dependent data instead of the reduced temperaturę nomogram; his reason is a lack of data for the nomogram. Formatting the data in this way could be potentially dangerous to the user of this report. The author should have included only materia! properties that are in a form usable by the designer; i.e., a reduced temperaturę nomogram for producing reliable data for engineering use. Other-wise. potential users can expect to be confused and possibly misled by the use of incomplete and unreli-able data. If the author did not have the required number of data points to generate a reduced temperaturę nomogram, he should add qualifiers to the data he does include, so that the user is aware of the potential dangers that could result from extrapolation or interpolation.

V.R. Miller 5331 Pathview Drive Huber Heights, OH 45424

ENGINE NOISE

R. Hickling and M.M. Camel, Editors Plenum Publishing, New York, NY 1982. 497 pages. $62.50

The organizers and editors of the international symposium on "Engine Noise: Excitation, Vibration, and Radiation" held at the General Motors Research Laboratories on October 11-13, 1981, should be highly commended for, first of all, sponsoring the conference and, secondly. publishing the papers that were presented. This symposium contained timely work relative to current problems and con-cepts that are applicable to noise control problems not necessarily associated with engine noise. Papers on engine noise and its various aspects were prepared by authors from universities, industry. and govern-ment.

The four sections of the book correspond to sessions held during the symposium. The first section contains new work on excitation sources of engine noise --including cylinder pressure pulsations. piston slap. gear noise excitation, and fuel-injection Systems -and their control. The session corresponding to this section was chaired by Theo Priede of the Univer$ity of Southampton. The second section deals with transmission paths and structural vibrations of engines. Dick Lyon, Massachusetts Institute of Technology, headed the session. Topics included vibration transmission analysis, noise and vibration in linkages. engine structure vibrations, and finite element techniques to assess the noise of engine structures. The third session, chaired by J.Y. Chung of the General Motors Research Laboratories, was concerned with noise radiation from engine surfaces. including acoustic intensity measurements of engine noise and comparisons of different measurement approaches. Methods for compoling engine noise surface acoustic radiation are presented as are numer ical methods for acoustic problems. The finał session, which was chaired by Jerry Manning of Cambridge Collaborative, Inc., described practical methods for reducing engine noise This section presents methods for using enclosures for noise reduction and for modifying sources to alter noise and vibration mechanisms that cause problems.

Included at the end of each paper are the discussions that followed the presentations. In some cases written comments received from the audience were printed. The book contains a list of conference participants. an author and contributor index. and a subject index.

The concepts. techmques. and methods are presented in such a way as to make ihem valuable to those interested in noise control. This book should be of interest to those who work in noise control in the areas of community and factory noise and to those in the transportation industry.

V.R. Miller 5331 Pathview Drive Huber Heights. OH 45424