THE EFFECT OF AIR-GENERATED SOUND WAVES ON SUSPENSIONS OF MICROORGANISMS
PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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Two high-intensity air-borne sound generators, a siren and a je r T- type whistle, were used to study the effects of sound on liquid suspensions of bacteria. Special techniques and exposure chambers were developed. Lethal effects and cellular disruption were most obvious wit certain strains of Micrococcus pyogenes var. aureus, but they were irreproducible over a period of months. The experiments failed to elucidate the mode of action of the acoustic field in producing a sharp threshold for the lethal effects. The data showed that bacteria can be killed in standing wave fields with maximum pressure amplitudes of a few tenths of an atm and maximum particle velocities of a few cm. The sound sources indicated a relative scale of bacterial sensitivity to low-intensity sound fields.