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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.

Geoacoustic characterization of a range-dependent environment

Fallat, Mark Ryan. 10 April 2008 (has links)
No description available.

Simulation of the acoustic pulse expected from the interaction of ultra-high energy neutrinos and seawater

Gruell, Michael S. 03 1900 (has links)
The purpose of this thesis was to design, build, and test a device capable of simulating the acoustic pulse expected from the interaction between an Ultra-High Energy (UHE) neutrino and seawater. When a neutrino interacts with seawater, the reaction creates a long, narrow shower of sub-atomic particles. The energy from this reaction causes nearly instantaneous heating of the seawater on an acoustic timescale. The acoustic pulse created by the resulting thermal expansion of the water is predicted to be bipolar in shape. This work was undertaken to support a Stanford experiment, the Study of Acoustic Ultra-high energy Neutrino Detection (SAUND), that uses existing hydrophone arrays to detect UHE neutrinos from the acoustic pulse generated by their rare interactions with seawater. The device fabricated for this thesis uses the discharge current from a 4 microFarads capacitor charged to 2.5kV to heat the seawater between two copper plates. The anode and cathode plates of this "zapper" design were 6 cm in diameter and 20 cm apart. The acoustic pulse generated by the zapper was measured both in a small test tank at NPS and at the Acoustic Test Facility located at NUWC Keyport. Bipolar pulses observed at NPS on two separate test dates had average pulse lengths of 110 microseconds +/- 10 microseconds and 160 +/- 20 microseconds and average amplitudes at 1m of 1.9 +/- 0.3Pa and 4.7 +/- 0.6Pa. The average pulse length recorded at Keyport was 49 +/- 6 microseconds and the average amplitude at 1m was 6.4 +/- 0.9Pa. The pulse lengths recorded at NPS were reasonably consistent with theory, however all pressure amplitudes were about 100 times lower than predicted. The cause of the amplitude discrepancy is not completely understood at this time.

The numerical solution of the dynamic fluid-structure interaction problem

Harris, Paul John January 1989 (has links)
In this thesis we consider the problem of the dynamic fluid-structure interaction between a finite elastic structure and the acoustic field in an unbounded fluid-filled exterior domain. We formulate the exterior acoustic problem as an integral equation over the structure surface. However, the classical boundary integral equation formulations of this problem do not have unique solutions at certain characteristic frequencies (which depend on the surface) and it is necessary to employ modified boundary integral equation formulations which are valid for all frequencies. The modified integral equation formulation used here involves certain arbitrary parameters and we shall study the effect of these parameters on the stability and accuracy of the numerical methods used to solve the integral equation. We then couple the boundary element analysis of the exterior acoustic problem with a finite element analysis of the elastic structure to investigate the interaction between the structure and the acoustic field. Recently there has been some controversy over whether or not the coupled problem suffers from the non-uniqueness problems associated with the classical integral equation formulations of the exterior acoustic problem. We resolve this question by demonstrating that the solution to the coupled problem is not unique at the characteristic frequencies and that we need to employ an integral equation formulation valid for all frequencies. We discuss the accuracy of our numerical results for both the acoustic problem and the coupled problem, for a number of axisymmetric and fully three-dimensional problems. Finally, we apply our method to the problem of a piezoelectric sonar transducer transmitting an acoustic signal in water, and observe reasonable agreement between our theoretical predictions and some experimental results.

A study of the spectral and directional properties of ambient noise in Pugent Sound /

Dall'Osto, David R. January 2009 (has links) (PDF)
Thesis (M.S.M.E.)--University of Washington, 2009. / Includes bibliographical references (p.75-77). Also available on the World Wide Web.

Overwintering abundance and distribution of striped bass (Morone saxtilis) in the Hudson River Estuary using hydroacoustic techniques

Nagy, Brian W. January 1900 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 113 p. : ill. (some col.), col. map. Vita. Includes abstract. Includes bibliographical references.

A study of the spectral and directional properties of ambient noise in Puget Sound

Dall'Osto, David R. January 2009 (has links) (PDF)
Thesis (M.S.M.E.)--University of Washington, 2009. / Title from Web page (viewed on Feb. 3, 2010). Includes bibliographical references (p.75-77).

Detection of binary phase-shift keying signal in multioath propagation /

Jung, Du San. January 2002 (has links) (PDF)
Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Charles W. Therrien, Murali Tummala. Includes bibliographical references (p. 83-84). Also available online.

Direct-sequence spread-spectrum acoustic communications with CRV Decomposition /

Angelopoulos, Pavlos. January 2004 (has links) (PDF)
Thesis (M.S. in Electrical Engineering and M.S. in Engineering Acoustics)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Roberto Cristi, Kevin B. Smith. Includes bibliographical references (p. 91-94). Also available online.

Design and testing of a low-frequency, water-filled sound exposure chamber

Lentz, Toby Robert 12 1900 (has links)
No description available.

Structural and acoustic response of motion sensors mounted on a compliant coating

Fisher, Karl Albert 08 1900 (has links)
No description available.

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