The subject matter contained in this thesis is concerned with the measurement and prediction of some of the parameters of an artificial dielectric, consisting of a mixture of fine aluminum powder in paraffin wax or alkyd (100) foam.

Use of a membrane antenna on remote sensing satellites is now possible because of new materials and manufacturing technologies. This would allow space organizations to cut cost and weight by a non-negligible factor. All possible failure modes must be fully analyzed before these are sent to space. With membrane antennas, a new type of failure mode must be looked at: wrinkling. The wrinkling of the emitting layer could greatly undermine the performance of the antenna by modifying the orientation of the radiating elements rendering the wrinkle-affected area useless. It has been anticipated that such wrinkling could occur under temperature variations in space. There is currently a lack of available analyses for predicting with confidence the behaviour of such stretched material in a space environment. This work develops and establishes a finite-element approach as a potential method for predicting wrinkle height and orientation under thermal loads. Some designs for controlling the wrinkles are introduced with the benefits of optimizing the antenna area. The influence of the variation of the parabolic edges and corner cut-offs on the required cable load has been studied. Dynamic behaviour poses a concern, especially with a larger and flexible membrane and has been studied to determine the natural frequencies and the response of the antenna to on-orbit micro-vibrations . / L'utilisation d'une antenne membrane sur les satellites de télédétection est désormais possible par la fabrication de nouveaux matériaux et le développement de nouvelles techniques manufacturières. Une telle antenne permettrait aux organisations possédant de tels satellites d'en réduire le poids et du fait même le coût de lancement par un facteur important. Toutes les causes d'échec, de panne ou d'insuccès reliées à l'utilisation d'une antenne membrane doivent être pleinement étudiées avant qu'elle ne soit lancée. Avec l'émergence de cette nouvelle technologie, une nouvelle problématique s'ajoute: le plissement. Le plissement de la membrane émettrice pourrait affecter l'efficacité del'antenne et réduire ses performances électriques en modifiant l'orientation des éléments radiatifs de la membrane rendant ainsi inopérante la région affectée. Les variations de température présentes dans l'espace peuvent produire de tels plissements. Très peu d'analyses sont disponibles pour prédire en toute certitude le comportement d'une telle membrane en orbite. Cette étude propose l'étude d'une approche par éléments finis analysant la hauteur et l'orientation des plissements dues aux variations de température. Le contrôle des ridules par méthode passive a été également étudié permettant l'optimisation de l'aire et des dimensions de la membrane. L'influence de la forme parabolique des cotés de la membrane sur la force axiale du câble de tension a été étudiée et est présentée. Le comportement dynamique de la membrane est l'objet d'une attention particulière étant donné sa propension à amplifier les micro vibrations . fr

The main work of this paper is the description of electronic equipment that has been developed to measure the parameters of junction transistors over an appreciable frequency range and with changing bias points.

When a beam carries a load, which does not act through its shear center, torsional stresses are introduced along with the flexural stresses. Torsion may be a serious factor in producing beam failures. Rib reinforcement can reduce torsional stresses and angles of twist. The purpose of this investigation was to determine the influence web stiffeners have on these stresses and twist angles.

The laws which govern the flow of fluids in regular conduits have been extensively studied and definite patterns of behaviour have been resolved. However, there is still much work to be carried out before the principles underlying the flow of fluids through irregular channels--such as those formed between the particles in a packed bed--are thoroughly understood. The problem is admittedly difficult, not so much because of the large number of variables involved, but rather because of the complex nature of some of the latter. [...]

An understanding of the behavior of brittle solids subjected to stresses is not only of academic interest, but is of great importance in engineering practice. In particular, the stress response of rock masses merits doser attention. Most large engineering projects utilize rock materials either directly, as part of the structure, or indirectly, as the foundation upon which the structure will rest. In tunneling and in mining, excavations are completely surrounded by rock and usually induce in it the extreme stress response of ultimate failure. [...]

The heat transfer from water to a bed of spherical Alundum pebbles is investigated. From fundamental principles it is shown that for the same bed the heat exchange is governed by the dimensionless groups Pr, Re and [...]

An apparatus has been developed to study entrance region heat transfer in circular pipes and tubes. Previous work on entrance region heat transfer by J. T. Rogers showed that for a given Reynolds number, higher heat transfer coefficients are obtained with increasing bulk temperatures. Present work confirma Rogers' findings and shows that a temperature correction factor is necessary to account for this increase in the value of heat transfer coefficients with increasing temperatures. [...]

Thesis (D.E.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2005. / Consists of the author's previously published papers. Includes bibliographical references. Also available in a print form.

Thesis (M.S. in Systems Technology)--Naval Postgraduate School, June 2009. / Thesis Advisor(s): Pfeiffer, Karl D. "June 2009." Description based on title screen as viewed on July 13, 2009. DTIC Identifiers: Napoleon. Author(s) subject terms: TERMS Napoleon Bonaparte, Information Systems Engineering, Systems Engineering, Command and Control, Organizational Design, Grand Armee. Includes bibliographical references (p. 43-44). Also available in print.