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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.
241

Principles for open-arc weld deposition of high-chromium white iron surface layers / John Anthony Francis.

Francis, John A. January 1999 (has links)
Bibliography: leaves 191-198. / xxi, 201 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines the mechanisms controlling the dilution, geometry and wear performance of weld- deposited high-chromium white iron surface layers. Focuses on layers deposited by mechanised flux-cored-arc welding, as this process achieves higher deposition rates than manual-metal-arc welding and affords a greater degree of control over individual welding variables. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1999
242

Metal plasma immersion ion implantation and deposition using polymer substrates

Oates, T. W. H January 2003 (has links)
This thesis investigates the application of plasma immersion ion implantation (PIII) to polymers. PIII requires that a high negative potential be applied to the surface of the material while it is immersed in a plasma. This presents a problem for insulating materials such as polymers, since the implanting ions carry charge to the surface, resulting in a charge accumulation that effectively neutralises the applied potential. This causes the plasma sheath at the surface to collapse a short time after the potential is applied. Measurements of the sheath dynamics, including the collapsing sheath, are performed using an electric probe. The results are compared to theoretical models of the plasma sheath based on the Child-Langmuir law for high voltage sheaths. The theoretical model predicts well the sheath dynamics for conductive substrates. For insulating substrates the model can account for the experimental observations if the secondary electron coefficient is modified, justified on the basis of the poly-energetic nature of the implanting ions. If a conductive film is applied to the insulator surface the problem of charge accumulation can be avoided without compromising the effectiveness of PIII. The requirement for the film is that it be conductive, yet transparent to the incident ions. Experimental results are presented which confirm the effectiveness of the method. Theoretical estimates of the surface potential show that a film of the order of 5nm thickness can effectively circumvent the charge accumulation problem. Efforts to produce and characterise such a film form the final two chapters of this thesis. The optimal thickness is determined to be near the percolation threshold, where a marked increase in conductivity occurs. Spectroscopic ellipsometry is shown to be an excellent method to determine the film thickness and percolation threshold non-invasively. Throughout this work cathodic vacuum arcs are used to deposit thin films and as a source of metal plasmas. The design and construction of a pulsed cathodic vacuum arc forms a significant part of this thesis. Investigations of the cathode spots and power supply requirements are presented.
243

Vers une nouvelle approche pour établir les besoins nutritionnels minimaux (en particulier ceux en P) de la truite arc-en-ciel (oncorhynchus mykiss) à l'aide de puces génétiques /

Lake, Jennifer. January 2007 (has links) (PDF)
Thèse (M.Sc.)--Université Laval, 2007. / Bibliogr.: f. 81-90. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.
244

Seam position detection in pulsed gas metal arc welding

Shen, Hao. January 2003 (has links)
Thesis (M.Comp.Sc.(Hons.))--University of Wollongong, 2003. / Typescript. Includes bibliographical references: leaf 49-55.
245

Optimization of metal transfer and fusion using current control in dip transfer GMAW

Dean, Gary. January 2003 (has links)
Thesis (Ph.D.)--University of Wollongong, 2003. / Typescript. Includes bibliographical references: leaf 8.1-8.10.
246

Geochemical and helium isotopic variability within the Lau Basin /

Goddard, Charlotte Ives. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 168-187). Also available on the World Wide Web.
247

Energy and voltage management methods for multilevel converters for bulk power system power quality improvement

Yazdani, Atousa, January 2009 (has links) (PDF)
Thesis (Ph. D.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed February 18, 2009) Includes bibliographical references.
248

Utilisation d'huile végétales dans la ration de salmonidés : une approche de développement durable en aquaculture /

Bélanger-Lamonde, Amélie. January 2007 (has links) (PDF)
Thèse (M.Sc.)--Université Laval, 2007. / Bibliogr.: f. [94]-108. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.
249

Interactions compétitives entre le saumon atlantique et la truite arc-en-ciel : aspects écologiques, sélectifs et adaptatifs /

Blanchet, Simon. January 2007 (has links) (PDF)
Thèse (Ph. D.)--Université Laval, 2007. / Bibliogr.: f. [166]-181. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.
250

Distribution et abondance des larves d'éperlan arc-en-ciel (Osmerus mordax) au lac Saint-Jean /

Gagnon, Karine, January 2005 (has links)
Thèse (M.Ress.Renouv.) -- Université du Québec à Chicoutimi, 2005. / Bibliogr.: f. 79-85. Document électronique également accessible en format PDF. CaQCU

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