Volume 2, Issue 1, January 2006
Index of content:
2(2006); http://dx.doi.org/10.1121/1.2961130View Description Hide Description
A new global network of microbarometers is breathing life into a once dormant branch of acoustics: the study of infrasound. The nascent study of sub‐audible sounds is shedding new light on a great variety of man‐made and natural phenomena in the atmosphere, including Mount Saint Helens, pictured on the front cover of this issue. The re‐emergence of this field is due largely to the Comprehensive Nuclear‐Test‐Ban Treaty (CTBT), which was opened for signatures in New York City in September of 1996. The CTBT held the promise of limiting the spread of nuclear weapons. In the process, the treaty created the International Monitoring System (IMS). The International Monitoring System consists of seismic, hydroacoustic, radionuclide, and sixty infrasound stations spread over the globe to provide almost uniform coverage (Fig. 1).
2(2006); http://dx.doi.org/10.1121/1.2961126View Description Hide Description
Recently there has been substantial renewed interest by ASA members and others regarding the transient sounds of supersonic airplanes, called sonic booms. In fact, during July 21–22, 2005 an International Sonic Boom Forum was held in State College, PA, organized by the present author and Francois Coulouvrat of the French National Center for Scientific Research (CNRS) at Pierre and Marie Curie University (Paris VI). This Forum was a set of special sessions of the 17th International Symposium on Nonlinear Acoustics, co‐sponsored by the ASA. There were 30 technical papers as well as panel discussions from industry and government. Participants were from seven countries, and included presentations by the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), industry, and university researchers. Clearly there has been recent resurgence of interest in sonic boom, including new funded research. Where is all this new interest coming from? This article will try to answer this question and provide some highlights of recent sonic boom research.
2(2006); http://dx.doi.org/10.1121/1.2961127View Description Hide Description
When James E. West was 8 years old, he propped himself on his bed's brass footboard one afternoon and stretched to plug the cord of a radio he had repaired into a ceiling outlet. It was one of his first experiments. Mr. West's hand sealed to the light socket as 120 volts of electricity shimmied through his body, freezing him in place until his brother knocked him from the footboard and onto the floor.
Like more storied inventors who preceded him, he was quickly hooked on the juice—even as he lay shivering from that first encounter. “I became fascinated by electricity after that, just completely fascinated,” recalled Mr. West, now 74 and an award‐winning research professor at Johns Hopkins University. “I needed to learn everything I could about it.”
2(2006); http://dx.doi.org/10.1121/1.2961128View Description Hide Description
Clickity‐clickity‐clickity‐CLACKity … clickity‐clickity‐clickity‐CLACKity … what is creating that background noise in your office, in your home, or in the movie theater? It may be hard to pinpoint, but certainly it can cause you different kinds of distress. It may make you annoyed, disturb the flow of conversation, interrupt your sleep, cause fatigue, and even impact how productive you are. Some of the most pervasive sources of background noise are the modern heating, ventilating, and air‐conditioning (HVAC) systems that keep us at comfortable temperatures indoors. These systems range broadly from the window unit in your apartment to a chiller supplying chilled water to cool a gymnasium in the summer.
2(2006); http://dx.doi.org/10.1121/1.2961129View Description Hide Description
It has been known for decades that many marine animals make underwater sounds ranging in frequency from 10 Hz to over 100 kHz. Associating various sounds with specific species has been an active research topic to which members of the Acoustical Society of America (ASA) have made substantial contributions. A good start on this topic can be found in Reference 1 or by consulting the Macaulay Library of Sounds at Cornell University (http://www.birds.cornell.edu/macaulaylibrary/).