Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 7 of 7 for “"Broadband Attenuation"”.
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Broadband Acoustic Liner Optimization Study Using Novel Poro-elastic Materials
… for acoustic liner configurations that target broadband performance. This thesis experimentally and analytically investigates passive noise control methods to improve broadband frequency attenuation through various acoustic liner designs. The inclusion of acoustic metamaterials within these …
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Control of broadband acoustic radiation from structures using a piezoelectric double-amplifier active-skin
… active-skin is demonstrated for the reduction of broadband acoustic radiation from a vibrating structure. A simplified representation of the active-skin, employing acoustic monopoles as secondary sources, is explored as a precursor to the more complicated analyses of the device. Many design issues …
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Feedback Applications in Active Noise Control for Small Axial Cooling Fans
… (ANC) has been applied as a means of attenuating broadband noise from a small axial cooling fan. Such fans are used to maintain thermal stability inside of computers, projectors, and other office equipment and home appliances. The type of low-level noise radiated from axial cooling fans has been …
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The study and development of distributed devices for concurrent vibration attenuation and energy harvesting
This work focuses on the broadband attenuation of structural vibration and, in the process, employs a new perspective of vibrational energy harvesting devices. The first part of the research studies and develops a continuously distributed vibration control device which combines the benefits of …
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Investigation of physical and psychophysical methods for the attenuation measurement of circumaural hearing protectors with implication for field use
… measure is needed to estimate the attenuation workers are achieving with their hearing protectors in the field. Alternative measures for assessing a hearing protector's effectiveness were evaluated through comparison to the standardized real-ear attenuation at threshold (REAT) …
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Speech intelligibility in tracked vehicles and pink noise under active noise reduction and passive attenuation communications headsets
… mode, however, provided a greater degree of broadband attenuation especially in the lower frequency range, e.g. < 630 Hz. Phase reversal proved to be of no benefit to performance in either noise environment. The pink noise proved to be the harsher environment for speech intelligibility than …
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Modeling and Estimation of Linear and Nonlinear Piezoelectric Systems
… Arrays (PSOAs) for the wideband vibration attenuation problem. PSOAs offer a straightforward and low mass ratio solution to cancel out the resonant peaks in a host structure's frequency domain. Further, they provide adaptability through shunt tuning, which gives them the ability to recover …