Acoustical Society of America
Gold Medal Award - 2002

Robert E. Apfel

ROBERT EDMUND APFEL was born on March 16, 1943 to Mark and Anita Apfel in New York City. Bob developed a creative spirit and a love for the well-put word while growing up with two brothers in Harrison, NY. He first developed an interest in acoustics at Tufts University, where he graduated magna cum laude in 1964, also earning his Phi Beta Kappa pin. As a senior, he merged a love of both music and physics by studying the acoustics of a Tufts performance hall. In executing this project he was fortunate to obtain the support of Bolt, Beranek and Newman for access to instrumentation, and particularly to Bill Cavanaugh, for some sound advice. In the fall of 1964 he was off to Harvard to do this Ph.D. work in Ted Hunt's acoustics lab. During a visit to his old Alma Mater he met a young freshman, Nancy Howe. Soon Nancy joined Bob at Harvard, and they were married. They both received their graduate degrees from Harvard in 1970; Bob, a PhD in Applied Physics, and Nancy, a Master's in Education. They have two children, Darren and Alison.

Bob is a prolific researcher. Writing about Bob, Ted Hunt said, "[He has] a breadth of scientific interest and a subtle trait that I can only describe as scientific zing. Apfel has it and he communicates it," Bob has published over 140 papers in 36 different journals, and has been granted 4 patents, two related to biomedical applications. Among his papers are 41 articles in the Journal of the Acoustical Society of America (JASA).

One of the fundamental properties of nature is the ultimate tensile strength of liquids. At a basic level, this impacts such diverse fields as the performance of bubble chambers, ultrasonic cleaners, medical ultrasound, catalysts for chemical reactions, the efficiency of hydraulic turbines and the noise generated by ship propellers. Theoretically the tensile strength of water should be on the order of a hundred megapascals. Yet, measurements over a broad range of acoustic frequencies reveal that water can seldom sustain more than a single megapascal. It was long suspected that microscopic inhomogeneities (dirt and other particulate matter) acted as nucleation sites, providing preferential locations for liquid failure under tension. While former Acoustical Society of America Gold medallist Moe Greenspan laboriously filtered water to remove its impurities, he still could not achieve tensile strengths in excess of 25 megapascals. Bob reasoned that no matter how carefully one tried to remove the dirt, it was simply too difficult to get the required purity in large samples. He conceived of testing the tensile strength of microliter-sized drops, whose small volumes could result in a perfectly clean liquid in a reasonable fraction of the sampled drops. To perform this experiment he had to develop innovative techniques in "acoustic levitation." By acoustically levitating microliter drops and stressing them with sound and high temperatures, Bob was able to report in JASA, and in Nature, that many liquids could achieve their theoretical strengths. With this amazingly creative and difficult research effort under his belt, he was able to finish his Ph.D. thesis!

Bob's creativity is multi-faceted. He has written a paper describing a unique method for deriving Einstein's time dilation formulas, and an article on "Whispering waves in a wineglass." Although he teaches in the mechanical engineering department, he also lectures to students of architecture at Yale. He has written a primer on architectural acoustics titled "Deaf Architects and Blind Acousticians? A Guide to the Principles of Sound Design." He edited Ted Hunt's unfinished book Origins of Acoustics, which was then published by Yale University Press. He also worked with Tom Hunt, Ted's son, to help establish the ASA's. F.V. Hunt Postdoctoral Research Fellowship in Acoustics. Several Hunt Fellows have had the special opportunity to work in the creative atmosphere of Bob's lab. Remarkably, he has also written a screenplay, books on creativity and the nature of our humanity, and over thirty Valentine sonnets to Nancy. While his scientific writings are widely read, few of these latter works have yet been published, though at this writing, his CV includes the citation, "Animation-Accommodation-Authorization Theory of the Human Personality," New Ideas in Psychology, Vol. 19(2), pp. 145—168 (2001).

With the expansion of the Internet, and the immediacy of information that it provided, it was soon obvious to Bob that the conventional practice of publishing research articles on paper and housing them in libraries could be enhanced. Since the culture, if not the reality, of the Internet is that everything is free, the financial health of professional societies such as the ASA, which rely heavily on income from journal subscriptions, was in jeopardy. Always a forward thinker, Bob carefully analyzed ways in which electronic publishing would prove both an asset to the scientist or engineer, but not undermine the financial backbone of our professional societies. As a member of the American Institute of Physics (AIP) Governing Board, Bob argued that the unwieldy and time-consuming practice of mailing paper manuscripts back and forth between authors and reviewers could be supplanted with an all-electronic system. He was one of the first to conceptualize a fully-electronic, manuscript management system in which the entire process of publication, from submission through peer review to publication could be accomplished electronically. Within the ASA, Bob convincingly argued that there was no alternative—it was the wave of the future, and those engaging this problem early would be the eventual winners. This arguments prevailed and AIP implemented such an automated system for the ASA. As a result of his foray into electronic publishing, he also conceived of ARLO, Acoustic Research Letters Online, which has been mimicked by a number of other totally electronic publications. ARLO, a new publication of ASA, stands as a beacon of Bob's creativity and perseverance. Bob led the ASA into electronic publishing and was influential in related developments at the AIP as well. As a result, the ASA remains a leader in the effective distribution of scientific knowledge.

Bob's talents have been widely recognized by his colleagues. In 1971, he received the A. B. Wood Medal from the Institute of Acoustics (UK) for his fundamental work on the properties of liquids. In 1976, he was awarded ASA's Biennial Award, now the R. Bruce Lindsay Award. In 1997, he was recognized again with the Silver Medal in Physical Acoustics. His contributions to the Society have not been limited to scholarship. From 1979 to 1982, he served on the Executive Council. At a relatively young age he was elected Chair of the Technical Committee on Physical Acoustics, and became a founding member of the Committee on Long-Range Planning. He made distinguished contributions in the administration of the affairs of the Society as the Vice President-elect (1990–91), as Vice President (1991–92), as President-elect (1994–95), and as the Society's President during 1995–96.

By awarding Bob the ASA's Gold Medal, we recognize him for this research discoveries, his leadership, and his many creative innovation. However, his legacy contains another more human dimension—his students. He has mentored more than 47 students and colleagues in his lab at Yale, and they are rapidly assuming major roles in our Society. Two have served on the Executive Council and three have chaired Technical Committees.

Bob is modest when his contributions are recognized, always being quick to comment that there are others more deserving of recognition than he. A poem he wrote, "On the occasion of the 1976 Biennial Award of the Acoustical Society of America," beings with the lines, "There must be some mistake; this couldn't be for me..." and continues on to recognize his "parents, wife, children, mentors and colleagues for any contribution that he might have made." In spite of his protests, we who have heard Bob speak recognize his importance as a spokesperson and ambassador for acoustics, a dynamic speaker who employs demonstrations, metaphors, and images to bring his audience into his world. The Acoustical Society is fortunate to have his energy, his vision and his creativity employed on our behalf, and we honor Bob Apfel for his hard work and dedication to our Society.

Larry Crum
Carr Everbach
Christy Holland
Ron Roy