In a previous study, it was hypothesized that ultrasound-induced lung damage was related to the transfer of ultrasonic energy into the lungs (W. D. O'Brien et al. 2002, "Ultrasound-induced lung hemorrhage: Role of acoustic boundary conditions at the pleural surface," J. Acoust. Soc. Am. 111, 1102-1109). From this study a technique was developed to: 1) estimate the impedance (Mrayl) of fresh, ex...

We present a concept of "active material" with variable acoustic properties, being constituted of an electroacoustic transducer which acoustic impedance can be changed by an active mean. Among the different ways to obtain variable acoustic properties on an electroacoustic transducer's voicing face is the shunting of the transducer's electrical input. With such shunt devices, the acoustic impeda...

In 1946, Metz described what was probably the first practical impedance bridge for measurement of the acoustic reflex. Over the next four decades, diagnostic use of the acoustic reflex progressed in parallel with instrumentation refinements. Today, acoustic reflex threshold and decay testing are a routine component of the diagnostic audiology test battery. Recent advances in the measurement of ...

Scanning Acoustic Microscopy (SAM) can deliver information on mechanical properties. For the investigation of bone microstructure we found the acoustic impedance as the most suitable parameter.A spatial resolution of approximately 1 um at 1 GHz allows morphological studies at the level of cellular structures. For quantitative analysis at high frequencies a smooth and plane surface is essential....

In a previous study [J. Acoust. Soc. Am. 108, 1290 (2000)] the acoustic impedance difference between intercostal tissue and lung was evaluated as a possible explanation for the enhanced lung damage with increased hydrostatic pressure, but the hydrostatic-pressure-dependent impedance difference alone could not explain the enhanced occurrence of hemorrhage. In that study, it was hypothesized that...

The Virtual Flute is a web service that provides many thousands of machine-predicted alternative fingerings. Alternative fingerings can offer variations in intonation and timbre, and can be easier to play in different musical contexts. Many play multiphonics. An advanced fingering guide is invaluable when exotic effects and demanding passages are required of the player. The Virtual Flute uses a...

We report a web service for flute players, ‘The Virtual Boehm Flute’, that provides alternative fingerings which may be easier to play, less awkward to finger and/or more in tune for different circumstances. It also provides possible fingerings for multiphonics (chords). It uses an expert system that predicts the playability of notes from features in the input impedance spectra, based on the pl...