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 266 for “"Laser Doppler"”.
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Digital signal processing techniques for laser-doppler anemometry
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1990.
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Three-dimensional velocity extraction using laser Doppler vibrometry
… also need to be measured. Now with the use of a Laser Doppler Vibrometer the development of a method to measure three-dimensional velocities has provided the ability to measure in-plane velocities accurately. This thesis outlines the methods used for such three-dimensional extraction and gives an …
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Misalignment Effects of the Self-Tracking Laser Doppler Vibrometer
… further describes aspects of a self-tracking laser vibrometry system that can be used to measure the vibrations of rotating structures. This method, if setup correctly, has the capability to overcome many of the limitations listed above. A study of all misalignment effects is presented in this …
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Laser Doppler velocimeter measurements in a turbulent junction vortex
… a two-color, two-component, frequency shifted laser Doppler velocimeter. The mean flow field shows the presence of a single vortex on the plane of symmetry and a singular separation point upstream of the vortex. From the measured data, the locations of the vortex center and the singular …
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A rapidly scanning three-velocity-component laser Doppler anemometer
… three-velocity - component laser Doppler anemometer has been developed. It permits scans through 3-dimensional flows to obtain space-time velocity information. Since it has lower signal-averaging bias than pointwise measurements, only short record times are required to obtain …
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Laser Doppler Vibrometry Based Remote Sensing for Active Noise Control
… limit the performance of many ANC applications. Laser Doppler vibrometry, which works on the principle of optical interferometry, has been widely used in to measure vibrations in many vibro-acoustic applications. Yet, the developed instrument, laser Doppler vibrometer (LDV), has little been …
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Information Processing for Biological Signals: Application to Laser Doppler Vibrometry
… of recording bio-mechanical activity using a Laser Doppler Vibrometer. The LDV measures surface velocity on the basis of the Doppler shift. This device is targeted on the neck overlying the carotid artery, and the proximity of the carotid to the skin results in a strong signal. Vibrations and …
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Hydrogel Design Optimization for Measuring Ultrasound Using Laser Doppler Vibrometry
… benefit from a non-contact ultrasound system. Laser ultrasound (LUS) imaging offers potential advancements over conventional ultrasound, especially in achieving highresolution imaging of tissue structures and the elimination of liquid coupling mediums and probe-to-body contact. The thesis …
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Structural energy and power flow using a scanning laser Doppler vibrometer
… ESPF method consist of first using a scanning laser Doppler vibrometer (SLDV) to acquire spatially dense measurements of the structure's dynamic response. Second, the continuous 3-D complex-valued velocity field is solved from the laser data. Third, a spatially continuous model of the power is …
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The application of laser doppler technique to vibration measurement and position control.
The laser Doppler interferometer reported here was developed to investigate the possibilities of remote vibration and motion measurements. The method is noncontacting and operates with unprepared targets, using the diffusely scattered light to measure the axial component of the motion. A full …
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Application of Laser-Doppler Velocimetry to the Study of Coagulation and Sedimentation
… of model colloidal systems was measured by laser-Doppler velocimetry. This technique allows for rapid stability tests of dilute suspensions which affords a great savings of material over standard methods. The relative stability of dilute polystyrene latex particle (0.198 (mu)m diameter) …
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Laser Doppler velocimetry measurements of particle velocity fluctuations in a concentrated suspension
… tensor would be more realistic. We used laser Doppler velocimetry (LDV) to make a set of experimental observations of particle velocity fluctuations arising from inter-particle collisions in a concentrated non-colloidal suspension under nearly homogeneous shear flow in a narrow-gap …
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Three-dimensional vibrometry via three positions of a one-dimensional laser doppler velocimeter
… This technique uses a reference-beam type laser-doppler velocimeter in three independent positions to determine the target velocity in a non orthogonal coordinate system. The transformation from non-orthogonal to orthogonal coordinate systems is analyzed. The sensitivities of the resulting …
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Laser doppler anemometer measurements of Reynolds stresses in a fully developed pipe flow
A laser Doppler Anemometer (LDA) is used to make Reynolds stress measurements in a fully developed, turbulent pipe flow. Traverses are made to measure shear stress, normal stresses, and the correlation coefficient. To assess the accuracy of this system, these measurements are compared with results …
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A study of vascular reactivity in women with pre-eclampsia using laser doppler fluximetry
… complications of pregnancy of unknown aetiology. Laser Doppler fluximetry, a novel in-vivo technique, was used to assess cutaneous vascular reactivity in normotensive and pre-eclamptic women throughout pregnancy. The veno-arteriolar reflex was used as an index of peripheral vascular activity as it …
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Hydrodynamic drag of three-dimensional bodies by means of a Laser Doppler wake survey.
Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Ocean Engineering.
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Experimental investigation of vortex rings and helicopter rotor wakes using a laser Doppler velocimeter,
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1973.
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