Stand-off Interference Mitigation System

ABSTRACT: To address the Air Force"s need for a blast booth noise-reduction system, Physical Optics Corporation (POC) proposes to develop a new Stand-off Interference Mitigation (SIM) system, a noninvasive noise reduction system that can be mounted along the media blasting production line. The SIM system is based on a new design that utilizes mature POC-developed components. The innovation in quiet zones will enable the system to protect operators from excessive noise to meet OSHA"s 8 hr time-weighted-average (TWA) daily dose. This system offers no additional ergonomic stress to the operator, as it reduces noise without physically touching the operator within a surrounding quiet zone, which directly addresses the Air Force requirements for blast cleaning room (BCR) and blast cabinets (BC) working areas. In Phase I, POC plans to develop initial concept designs and model key elements for a system that reduces the blast booth noise level from 99 dB (SPL) to<80 dBA. In Phase II, POC will demonstrate the operation of a TRL-6 prototype blast booth noise reduction system that will reduce the noise at the ears to<80 dBA in the presence of continuous noise at 99 dB SPL. BENEFIT: The SIM system has significant commercial applications, including noise reduction for airlines, where the system can be mounted above each passenger to provide quiet zones during transport. It will also find use in noise minimization and cancellation of marine motors and in quieting motors, auditoriums, theatres, and opera houses, or ambient noise cancellation in commercial or residential buildings. Aeroacoustic noise is a major impediment to current and future civil aircraft designs. In addition to interior noise reduction, exterior noise reduction is a particular problem during landing and takeoff, as the resulting noise can be unacceptable in urban environments.