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 13 of 13 for “"acoustic output"”.
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Spatial Coherence-Based Adaptive Acoustic Output Selection for Diagnostic Ultrasound
… (FDA) provides guidelines for maximum acoustic output for diagnostic ultrasound imaging through metrics such as intensity, Mechanical Index (MI), and Thermal Index (TI). However, even within these guideline values, if the acoustic exposure levels used do not benefit image quality, they …
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Design and Modeling of Piezoelectric Micromachined Ultrasonic Transducer (PMUT) using a Multi-User MEMS Process for Medical Imaging
… the effect of critical design parameters on output performance. Three sets of PMUTs are fabricated based on the investigated parameters. The resonant frequency and acoustic output pressure of these fabricated devices are evaluated and compared based on their respective areas of the piezo …
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Backscatter Spatial Coherence for Ultrasonic Image Quality Characterization: Theory and Applications
… applications: 1) the automated selection of acoustic output, 2) model-based clutter suppression in B-mode imaging, and 3) adaptive wall filtering in color flow imaging. </p><p>A novel image quality metric, known as the lag-one coherence (LOC), was introduced along with the theory that relates …
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The Potential for Ultrasonic Image-Guided Therapy Using a Diagnostic System
… that can predict the potential for high acoustic output. A rigorous, nondestructive testing regimen for standard, diagnostic transducers to evaluate their potential for therapeutic use is formulated. Based on this work, transducer heating is identified as the largest challenge. The design …
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Hybrid percussion : extending physical instruments using sampled acoustics
… system architecture for creating hybrid digital-acoustic percussion instruments by combining extensions of existing signal processing techniques with specially-designed semi-acoustic physical controllers. This work aims to provide greater realism to digital percussion, gaining much of the …
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Investigation of a compact acoustic source array for the active control of aircraft engine fan noise
An array of small, lightweight acoustic sources was investigated to determine how such an arrangement of sources would acoustically interact with a duct similar to that of a turbofan engine inlet. The sources were cylindrically curved aluminum panels excited in vibration by the application of a …
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Finite Element Analysis of a Golf Ball and Driver Head Impact: Understanding the Feasibility of an Acoustical Optimization
An acoustic profile from the impact between a golf ball and driver head was produced using FEA. Following this, the results were analyzed to determine the feasibility of an acoustical optimization of such an impact. A validation of the FEA program LS-DYNA® was undertaken to ensure a proper solution …
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The Effect of a Lingual Magnet on Fricative Production: An Acoustic Evaluation of Placement and Adaptation
… these devices may have on the perceptual and acoustic characteristics of speech. This study examined the effect of placing a small magnet on the tongue of ten normal adult speakers while reading a sentence containing /s/ and "sh" in initial, medial and final position. Two different placements …
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Use Of Focused Ultrasound For Transcranial Sonothrombolysis
… pulse width settings</p> <p>(3) Characterize the acoustic field produced by the transcranial FUS and determine how it is affected by the skull</p> <p>(4) Determine how sonothrombolysis efficacy and potential clot fragmentation are impacted by varying the FUS intensity</p> <p>The observed, novel in …
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An investigation into the use of ultrasound in the synthesis of fine chemicals
… of reagents.<br/><br/>A calorimetry study on the acoustic output of the ultrasonic probe provided data at different temperatures, depths, solvents, and power settings. The resultant data was in strong agreement with previously published work.
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Signal processing in a loudspeaking telephone
… is limited to low-loss lines and produces a low acoustic output. An architectural for an instrument has been developed and tested, which uses digital signal processing to provide duplex transmission between a LST and a telopnone handset over most of the B.T. network. Digital adaptive-filters are …
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Spontaneous nasalization: An articulatory investigation of glottal consonants in Thai
… ‘nose-whistle-affinity’. Many articulatory and acoustic explanations have been proposed for spontaneous nasalization. First, vowels may nasalize near glottal consonants because they are underspecified for velopharyngeal opening and thus may be produced with a lowered velum. Second, low vowels …
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When nasal is more than nasal: the oral articulation of nasal vowels in two dialects of French
… of an articulatory (EMA and aerodynamic) and acoustic study of the realizations of three oral and nasal vowel pairs /a/-/˜ɑ/, /ɛ/-/˜ɛ/, and /o/-/˜ɔ/ recorded from 11 Northern Metropolitan French (NMF) and two Quebecois French (QF) female speakers in laboratory settings. Using simultaneous …