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 14 of 14 for “"Hearing Protectors"”.
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Spectral attenuation and wearability of circumaural hearing protectors as influenced by design attributes and work-related activity
Hearing protection devices (HPDs), a widely used countermeasure against noise-induced hearing loss, are laboratory-tested for their attenuation (noise reduction) capabilities. Unfortunately, laboratory tests overestimate the in-workplace performance of the devices, potentially leading to inadequate …
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The effect of passive and electronic amplitude-sensitive hearing protectors on the detection of a warning signal
An experiment was conducted to study earmuff wearers’ signal detection in noise performance and perceptions of comfort and acceptability with two amplitude-sensitive earmuffs as compared to their conventional counterparts. Passive and electronic amplitude-sensitive earmuffs were tested, represented …
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Instructional requirements for using the HML and NRR methods for estimating protected exposure levels under hearing protectors
… teaching individuals to calculate a protected hearing level given A- or C-weighted sound levels, and using the NRR and HML methods. Three instructional tools were evaluated: 1) outline instructions, 2) tabular nomogram, and 3) hypermedia computer-based instructions. Effectiveness was measured …
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Laboratory investigation of in-field influences on spectral noise attenuation and comfort of insert and circumaural hearing protectors
Laboratory-obtained, manufacturer-supplied hearing protector attenuation ratings typically overestimate the workers' protection level In the workplace. In addition, several work-related in-field factors often degrade protection performance of the hearing protection devices (HPDs), posing the threat …
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Investigation of physical and psychophysical methods for the attenuation measurement of circumaural hearing protectors with implication for field use
… 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) method, termed 1I3-REAT, a psychophysical …
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Field evaluation of noise attenuation and comfort performance of earplug, earmuff, and ear canal cap hearing protectors under the ANSI S12.6- 1984 sound field standard
… workplaces wearing 4 different industrial hearing protection devices (HPDs) while on the job. Over 2 consecutive 3-week periods of HPD use, the study investigated the effects of 2 different HPD fitting procedures (subject-fit versus trained-fit) on the spectral field attenuation and …
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Azimuthal Localization and Detection of Vehicular Backup Alarms Under Electronic and Non-Electronic Hearing Protection Devices in Noisy and Quiet Environments
Objective assessment for the effect of hearing protectors, background noise levels, and backup alarm acoustic features on listeners' abilities to localize backup alarm signals in the horizontal dimension, as well as on their ability to detect backup alarm signals in the distance dimension, is …
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Effects of anechoic vs. reverberant sound-field, subject gender, and outlier dismissal on the real-ear attenuation of hearing protection devices
… environment on the measured attenuation of hearing protection devices (HPDs) when using a standard real-ear attenuation at threshold (REAT) protocol. In the experiment, three earmuffs and three earplugs were tested in two diffuse sound fields implemented in two different sound environments …
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Low Frequency Modeling and Experimental Validation of Passive Noise Attenuation in Ear Defenders
… the dynamics that govern the attenuation of hearing protectors. This thesis duplicates some of this work with newer technology and better data processing ability. In addition to revitalizing the accepted knowledge of hearing protector technology, this thesis is the first documented effort to …
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Psychophysical investigation of the real-ear attenuation of hearing protection devices under different sound-field diffusivity conditions
… and international consensus standards governing hearing protection device (HPD) attenuation testing specify the use of a diffuse sound field to ensure the sound field remains uniform and random-incidence in an envelope about the subject’s head (ANSI, 1974; ANSI, 1984; British BSI 5108:1983; …
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An inter-laboratory investigation of ANSI standard fitting protocols, sample size, subject and experimenter gender, and trial on the real-ear attenuation of two types of earplugs
… differences of using two different hearing protection device (HPD) fitting procedures for testing the real-ear attenuation at threshold (REAT) of a popular vinyl foam earplug and a multi-sized premolded PVC single-flanged earplug. The first fitting procedure tested in the experiment …
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Effects of Earplug Material, Insertion Depth, and Measurement Technique on Hearing Occlusion Effect
… sound when the ear canal is occluded with hearing protection devices, hearing aids, or other canal-sealing inserts. Since the occlusion effect will enhance the hearing of bodily- generated sounds and result in distorted perception of one's own voice, many people report annoyance with …
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Evaluation of a Test Method for Assessing Horizontal Localization and Auditory Learning with Electronic Pass-through Hearing Protection
… warfighters and potential threats. However, hearing loss, acoustic trauma, or the use of hearing protection can diminish this vital ability to locate sounds in the environment accurately. The introduction of electronically modulated hearing protection and enhancement devices (HPED) is an …
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The Detection of Warning Signals While Wearing Active Noise Reduction and Passive Hearing Protection Devices
… individuals wore an active noise reduction (ANR) hearing protection device (HPD), a passive HPD, or no HPD. An ANR earmuff, a passive earmuff, and a user-molded foam earplug were tested in two types of noises (pink and red) at two different noise levels (85 dBA and 100 dBA). The signal used was an …