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 20 of 44 for “"Ear canal"”.
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Studies of the microenvironment and microflora of the canine external ear canal
… components of cerumen from healthy canine ears and those with otitis externa were studied. Interactions between canine cerumen and one member of the resident aural flora, Malassezia pachydermatis were also investigated. Gram-positive, coagulase-negative cocci, and M.pachydermatis were the …
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Effects of ear-canal geometry and middle-ear pressure on wideband acoustic reflectance
… immittance (WAI) measurements of the middle ear are studied. The body of work presented here has three major components: (1) design of a hearing measurement probe and probe tip, (2) extraction of the effects of the residual ear canal (REC) and estimation of the WAI at the tympanic membrane …
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Music Intensity in the Ear Canal in Quiet and in Subway Noise Using Four Different Headphones
<p><strong>Background</strong>: Noise-induced hearing loss, hearing loss caused by exposure to loud sounds, affects individuals of all ages. One cause of noise-induced hearing loss is listening to music at high intensities on personal listening devices, such as the iPhone. The aim of this study was …
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In vivo investigations of photoplethysmograms and arterial oxygen saturation from the auditory canal in conditions of compromised peripheral perfusion
… In order to overcome this problem, the ear canal was investigated as an alternative site for measuring reliable SpO2 on the hypothesis that blood flow to this central site is preferentially preserved. Novel miniature ear canal PPG sensors were developed along with a state of the art PPG …
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Calibration of a probe to match the acoustic signature of Er-10C and measurement of power reflectance and impedance of human ear canal
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-12-01
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Influence of insertion/donning instruction on frequency-specific sound attenuation achieved with ear canal caps and earmuffs with implications for industrial noise application
… dependency of sound attenuation capabilities of earmuffs and earcaps on various application instruction techniques including: (1) no instruction, (2) no instruction with 70 dBA auditory feedback, (3) manufacturers' package instruction, (4) detailed instruction, and (5) modeled instruction. The …
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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
A field research study was conducted to determine the actual noise attenuation and perceived comfort achieved by 40 noise-exposed industrial workers in 5 industrial workplaces wearing 4 different industrial hearing protection devices (HPDs) while on the job. Over 2 consecutive 3-week periods of HPD …
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Evidence of inner-ear mechanisms in bone conduction in chinchillas
… of how airborne sound is conducted to the inner-ear via the outer ear and middle ear, so-called air conduction (AC), the mechanisms by which vibrations of the head and body, so-called bone conduction (BC), produce an auditory response are not well understood. It is clear that the inner ear is the …
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Active noise reduction headphone measurement: Comparison of physical and psychophysical protocols and effects of microphone placement
… headphones cannot be tested and labeled as hearing protection devices (HPDs) due to inherent limitations with the existing psychophysical headphone testing standard, real-ear attenuation at threshold (REAT). This research focused on the use of a standard, for physical, microphone-in-real-ear …
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A Fully-Implantable Low-Noise Emi-Resistant Piezoelectric-Polymer Microphone and Amplifier for the Middle Ear
… microphone designed to operate with a cochlear implant. This thesis details the design, fabrication, and potential surgical implantation scheme for a fully differential and shielded cantilever made from polyvinylidene difluoride (PVDF)—a common piezoelectric polymer, as well as a low noise …
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Studies on the role of the mammalian external ear in directional hearing
The acoustical properties of the external ears of rabbits, rats and guinea pigs have been investigated by means of microphone or probe implants in the ear canal or tympanic bulla and by cochlear microphone (CM) recordings. The directional properties and transfer functions of the external ears were …
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Digital ear scanner : measuring the compliance of the ear
… paper seeks to resolve the biggest problem with hearing aids, their physical fit. By digitally scanning the ear canal and taking the dynamics of the ear into account the performance and comfort of a hearing aid can be greatly improved. Current optical techniques for 3-D imaging are too expensive …
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Finite Element Modeling and Exploration of Double Hearing Protection Systems
… requiring the improvement of current hearing protection devices. The improvement of passive hearing protection devices lies in examining the performance of major contributors to reduction of noise attenuation. The finite element method can be used to fully explore single hearing …
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Effects of Earplug Material, Insertion Depth, and Measurement Technique on Hearing Occlusion Effect
… components of body- transmitted 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 …
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Characterizing middle ear reflectance via pole-zero fitting
This thesis characterizes middle ear complex acoustic reflectance (CAR) and impedance by fitting poles and zeros to real-ear measurements. The goal of this work is to establish a quantitative connection between pole-zero locations and the underlying physical properties of CAR data. Most previous …
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Heritability of Spontaneous Otoacoustic Emissions
… emitted from the cochlea and measured in the ear canal with a sensitive microphone. Because these emissions are correlated with sex and because sex is genetically determined, Bilger et al. (1990) hypothesized that SOEs were inherited. This twin study was planned to pursue their idea. A total …
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Surgical system for image-based stereotaxy in the rat
… brains for neuroscience are based on dental and ear canal fixation and on skull based features which are at best crudely related to brain anatomy. As a result there is no accurate method or apparatus to place a probe into the brain of a research animal. Proposed here is a surgical system to …
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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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Interpreting otoacoustic emissions in humans : evidence for multiple generating mechanisms
Healthy ears generate sounds known as otoacoustic emissions that can be evoked and measured in the ear-canal using small, low-noise microphones. The ability to measure acoustic signals that originate within the cochlea provides noninvasive access to what in humans is an almost inaccessible organ. …
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The Chondroid Conundrum: Transpharyngeal Removal of Guttural Pouch Chondroids in Horses
… pus in a structure in an air-filled sac of the ear canal called guttural pouches (GPs). These concretions, called chondroids, allow affected horses to continue to pass on infection to other horses. Removal of chondroids is needed to stop disease transmission but current non-surgical and surgical …
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