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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.

The acoustic modelling of dissipative elements in automotive exhausts

Kirby, Raymond January 1996 (has links)
The mathematical modelling and experimental testing of both dissipative silencers and catalytic converters is reported here, although dissipative silencers are of primary interest. The models examined are formulated with a view to introducing them into commercial software aimed at the acoustic design of automotive exhaust systems.The porous materials which are commonly employed in dissipative silencers are examined first, and a semi-empirical model is formulated in order to predict the bulk acoustic properties of four different fibrous materials. Perforated tubes are also commonly employed in dissipative silencers separating the central channel from the absorbent, and the effects of both grazing flow and a backing layer of porous material upon the acoustic impedance of a perforate plate are examined.Three different theoretical approaches to modelling dissipative silencers are reported, and the accuracy of each method is assessed in the light of experimental sound transmission loss data measured for five different dissipative silencers. Mean flow in the central channel is a feature of each model, in addition to the use of the new semiempirical models for the perforated tube and the absorbent. A simple fundamental mode model is examined first, employing a straightforward analytical solution. More complex models are then investigated, incorporating finite element numerical methods. First, a fully general finite element model is examined and transmission loss predictions are obtained using both two and three dimensional meshes. A less complex eigenvalue solution, which also employs the finite element method, is examined next but this does not require such a high degree of computational effort. Predictions for finite length silencers are subsequently obtained using three different mode matching formulations. An examination of the accuracy of the predictions obtained using the different mathematical models is then carried out, from which conclusions are made concerning the future usefulness of each model in commercial design software. Finally, the effects of both mean flow and an axial temperature gradient upon the transmission loss of catalytic converters are examined. The relative influence the catalytic converter exerts sound attenuation, as compared to dissipative silencers, is also discussed.

Modeling and analysis of spacecraft battery charger systems /

Kim, Seong Joong, January 1991 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 166-169). Also available via the Internet

Integration and environmental qualification testing of spaecraft structures in support of the Naval Postgraduate School CubeSat launcher program

DeJesus, Adam C. January 2009 (has links) (PDF)
Thesis (M.S. in Space Systems Operations)--Naval Postgraduate School, June 2009. / Thesis Advisor(s): Newman, James H. "June 2009." Description based on title screen as viewed on July 14, 2009. Author(s) subject terms: Atlas, ABC, CubeSat, ESPA, EELV, NPSCuL, NPSCuL-Lite,, Picosatellite, Satellite, Space, Spacecraft, Structure, Launcher, Launch, ABC, Centaur, Qualification, Testing, Integration, Vibration. Includes bibliographical references (p. 91-92). Also available in print.

Design, construction, and evaluation of a portable skid tester

Gass, Donald Norbert, January 1966 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

System level simulation for electric vehicles /

Chan, Tai-wai, David, January 2000 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references.

Evaluation and simulation of electric vehicles /

Chan, To, Tony. January 1990 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1992.

Advanced concepts of the stability of two-wheeled vehicles application of mathematical analysis to actual vehicles.

Singh, Digvijai, January 1964 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

A stellar acquisition and tracking system for astronomical research from manned space vehicles

Seinfeld, Robert D. January 1962 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [91]-93).

An artificial neural network control system for spacecraft attitude stabilization /

Segura, Clement M. January 1990 (has links) (PDF)
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 1990. / Thesis Advisor(s): Burl, Jeff B. Second Reader: Cristi, Roberto. "June 1990." Description based on title screen as viewed on October 20, 2009. DTIC Identifier(s): Neural Networks, Attitude Stabilization, Spacecraft. Author(s) subject terms: Neural Networks, Attitude Stabilization, Pattern Matching Training, Time-Optimal Control Law, Performance Index Training. Includes bibliographical references (p. 69). Also available online.

The effects of operational parameters on vehicle directional responses

Sutantra, I. Nyoman. January 1900 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 303-308).

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