Acoustic microcavitation studies in the context of surface erosion are reported. Microcavitation in water-like hosts is induced by using acoustic tone bursts of appropriate strength at a low megahertz frequency. In characterizing intense tone bursts, the work details a novel method for measuring high-pressure fields that rapidly fluctuate. Specifically, acoustic pressure (tensile or compressive) amplitudes in excess of several megapascals have been precisely measured even when these oscillate a million times per second. In water-like liquids micron-size bubbles that are created and imploded in short durations, typically a few microseconds, characterize microcavitation. Micro-bubble implosions are known to deposit enormous energy densities at implosion locations. The effects of such implosions are felt only in the immediate vicinity of a cavitation event. Hence, such implosions might be useful in bringing about controlled erosion of thin surface films. In this dissertation microcavitation has been used to study surface erosion represented by removal of laser-xerographic ink prints from paper. Results indicate that all ink can be completely removed from an inked paper sample and that the paper left behind is entirely undamaged and immaculately clean. Acoustically influenced de-inking of paper has been characterized over a wide range of acoustic variables. Acoustic de-inking of scanned samples using fine transducers suggests that this process could be scaled up. The work establishes that acoustic-microcavitation-assisted-de-inking is a chemical-free, environmentally benign and energy-efficient process.
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