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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Doppler global velocimetry measurements in a wing flow field with tip blowing

Starn, Andrew Douglas. January 2004 (has links)
Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains vi, 101 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 41-45).
32

A pseudo-dual-Doppler analysis of cyclic tornadogenesis /

Dowell, David C., January 2000 (has links)
Thesis (Ph. D.)--University of Oklahoma, 2000. / Includes bibliographical references (leaves 105-115).
33

Radar signature characterization from wind turbine scattering

Naqvi, Aale R. 25 June 2014 (has links)
The growth in the number of wind farms has raised significant concerns in the radar community due to their potential interference on radar systems. The motion of the turbine blades creates unwanted Doppler clutter that can interfere in the tracking of moving targets. Large turbine structures can also produce electromagnetic shadows that may make observing objects behind a wind farm difficult. Detailed characterization of the clutter is the first step towards effective mitigation techniques. The goal of this dissertation research is to gain a better understanding of the dynamic radar signatures resulting from scattering by wind turbines. First, the scattering characteristics of turbines in the presence of ground surface are studied. Image theory in conjunction with a shooting-and-bouncing ray code, Ahilo, is used to carry out the dynamic signature simulation. The observed features in the simulation are corroborated with laboratory model measurements. Second, the effects of higher order motions of a turbine undergoing rotation on the radar signatures are investigated and characterized. Mathematical models for the motions are proposed and used to simulate the joint time-frequency and inverse synthetic aperture radar characteristics of the turbine undergoing these motions. The motions are studied for an isolated turbine as well as for a turbine rotating above a ground. Selected motions are corroborated by laboratory model measurements. Next, a method to remove the dynamic clutter produced by wind turbines is presented. A physics-based basis is constructed to model the radar backscattering from a wind turbine. This basis is used in conjunction with the matching pursuit algorithm to iteratively remove the Doppler clutter due to wind turbines. The algorithm is tested using radar return generated using Ahilo. Finally, radar features of wind turbines are simulated and studied in the HF (high frequency) band. The features are presented in the range-Doppler plane for single as well as arrays of turbines. Doppler aliasing due to the limited pulse repetition frequency of HF radars is examined. Shadowing characteristics of arrays of turbines are simulated and analyzed. Electromagnetic modeling details including effects of thin-wire modeling, non-conducting turbine components, and the presence of a conducting ground surface are discussed. / text
34

PROPERTIES OF ELECTROMAGNETIC TRANSITIONS IN FLUORINE-20 AND IRON-55

Hershberger, Robert Lee, 1941- January 1970 (has links)
No description available.
35

PROPERTIES OF SILICON-29 AND SILICON-31 NUCLEI FROM DOPPLER-SHIFT ATTENUATION MEASUREMENTS

Wozniak, Matthew J. January 1969 (has links)
No description available.
36

PROPERTIES OF SULFUR-35 AND COBALT-57 NUCLEI FROM ANGULAR CORRELATION ANDDOPPLER-SHIFT ATTENUATION MEASUREMENTS

Burton, Kenneth Shrum, 1941- January 1970 (has links)
No description available.
37

ELECTROMAGNETIC TRANSITIONS IN VANADIUM-51 AND MANGANESE-53

Goodman, Allan Stephen, 1942- January 1971 (has links)
No description available.
38

Laser doppler anemometry and its application to high temperature reactors

Ho, Thi Hien. January 1975 (has links)
No description available.
39

Ultrasound doppler evaluation of mechanical aortic heart valves

Ridgway, Andrea Janina 12 1900 (has links)
No description available.
40

An in vitro study of the relationship between fluid mechanical phenomena and signals from a 12 MHz doppler ultrasound guidewire in a model of coronary artery stenosis

Leclerc, Hélène 05 1900 (has links)
No description available.

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