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 78 for “"speed of sound"”.
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Speed of sound in unconsolidated sediments of Boston Harbor, Massachusetts
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1967.
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Bone speed of sound in overweight and normal-weight girls and adolescents
Over the last two decades, the prevalence of obesity in the general population has been steadily increasing. Obesity is a major issue in scientific research because it is associated with many health problems, one of which is bone quality. In adult females, adiposity is associated with increased …
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Image Reconstruction of the Speed of Sound and Initial Pressure Distributions in Ultrasound Computed Tomography and Photoacoustic Computed Tomography
<p>Ultrasound computed tomography (USCT) and photoacoustic computed tomography (PACT) are two emerging imaging modalities that have a wide range of potential applications from pre-clinical small animal imaging to cancer screening in human subjects. USCT is typically employed to measure acoustic …
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The (travel) times they are a changing : a computational framework for the diagnosis of non-alcoholic fatty liver disease (NAFLD)
… is based on two fundamental concepts: 1) the speed of sound in a fatty liver is lower than that in a healthy liver and 2) the quality of an ultrasound image is maximized when the beamforming speed of sound used in image formation matches the speed in the medium under examination. The proposed …
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High Speed Compressor Design
Abstract: High Speed Compressor Design A long-standing paradox exists in high speed compressor blade design. As the inlet flow to a row of blades approaches the speed of sound, the two-dimensional (2D) design of that blade row becomes exceptionally difficult, with designers laboriously trying to …
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Spirometer techniques for measuring molar composition in argon carbon dioxide mixtures
… for measuring gas composition through the use of a spirometer. A spirometer is high precision pressure transducer which measures the speed of sound in a gas through the emission and reception of ultrasonic pulses, commonly used in medicine to measure patient lung capacity. The spirometer was …
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Diffusive Acoustic Confocal Imaging System (DACI): a novel method for prostate cancer diagnosis
This thesis is part of the project undertaken to develop a diffusive acoustic confocal imaging system (DACI) that aims to differentiate between healthy and the diseased tissues in the prostate. Speed of sound is chosen as the tool to quantify the alterations in the tissues’ mechanical properties at …
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The observation of phase state and temperature using noninvasive ultrasonic waves.
… but most rely on physical contact or a line-of-sight path with the material. Many industries ranging from oil and gas to food and beverage could expand their application space in select scenarios if a noninvasive means were available to identify the internal temperature state of a material …
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Multidoman Piezo-Ceramic Cantilever
… that has many applications that are the subjects of current research. As a ferroelectric, PZT-5H has a permanent electrical polarization that arises from ferroelectric domains. In this thesis, numerical simulations were conducted via the well know Finite Element Method of several types of …
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3D organ property mapping using freehand ultrasound scans
… mapping has gained a considerable amount of interest in the recent years because of its diagnostic and clinical significance. Existing methods for 3D property mapping include computed tomography (CT), magnetic resonance imaging (MRI), and 3D ultrasound (3DUS). These methods, while capable …
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Injector Characterisation Measurement Technology for a Production Environment
The performance of Heavy-Duty common rail injectors is directly responsible for the power, efficiency, and emission levels of diesel engines. The variance in injector measurements, negatively impact performance and emissions characteristics of engines in real world applications. The main objectives …
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Experimental assessment of the internal flow behavior of supercritical carbon dioxide
This thesis presents an experimental assessment of the internal flow behavior of supercritical carbon dioxide. The investigation focused mainly on assessing condensation onset during rapid expansion of CO₂ into the two-phase region. An experimental blowdown test-rig with a modular test section was …
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Colliding and moving Bose-Einstein condensates : studies of superfluidity and optical tweezers for condensate transport
In this thesis, two different sets of experiments are described. The first is an exploration of the microscopic superfluidity of dilute gaseous Bose-Einstein condensates. The second set of experiments were performed using transported condensates in a new BEC apparatus. Superfluidity was probed by …
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The biomechanical properties of epithelial cells and tissue in two and three dimensions
… cues. This is also true during the onset of colorectal cancer, the second most common cause of cancer deaths in the Western world. Before the changes that occur during cancer onset can be understood, a better appreciation is needed of the mechanical forces and properties involved. …
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Measuring Density of Novel Technorganic Material
… its density. By ascertaining the density of the material, we hope to later derive other important properties including: the speed of sound within the material, its stiffness, its conductivity, and its natural frequency. The material in question was printed on a gold substrate by depositing …
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A comparison of two computer models of sound propagation for a wedge shaped ocean over a penetrable bottom
The problem of determining the acoustic pressure in a wedge shaped wave guide is examined. Two computer models, one using the method of images, the other using coupled normal modes, are compared. This comparison is over the benchmark wedge of the Acoustic Society of America. Three scenarios were …
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Measuring acoustic fields in an optical trap
This thesis describes progress in the use of optical traps for measurement of acoustic fields, a first step toward acoustic micromanipulation in fluids. The optical trap used throughout this study is carefully characterized. Eccentricity of measured distributions of thermal fluctuations of trapped …
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An Experimental Investigation Into the Effect of Plasma on the Flow Features of an Axisymmetric Jet
… did influence the mean and turbulent velocity profiles of the jets tested - allowing the jet core to penetrate further downstream. Large scale structure tracking indicated an increase in convective velocity of up to 5%. Heating of the shear layer by the plasma field was believed to bias the …
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Quantitative biomarkers for tissue characterization
… primary metrics investigated include estimation of longitudinal speed of sound and shearwave elastography. Additional metrics investigated include bioimpedance and functional tests specifically for muscle health quantification. Diagnosing and monitoring of health of muscle and liver tissue is the …
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Ferrofluid surface and volume flows in uniform rotating magnetic fields
Ferrofluid surface and volume effects in uniform dc and rotating magnetic fields are studied. Theory and corroborating measurements are presented for meniscus shapes and resulting surface driven flows, spin-up flows, and Hele-Shaw cell flows and instabilities. To characterize the water-based and …
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