Inaug.-diss.--K. Technische hochschule, Stuttgart.

Inaug.-diss.--K. Technische hochschule, Stuttgart.

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Structural Engineering, Department of Civil and Environmental Engineering, University of Alberta. Includes bibliographical references.

published_or_final_version / Industrial Engineering / Master / Master of Philosophy

No description available.

Dissertation submitted in compliance with the requirements for the Master's Diploma in Technology: Mechanical Engineering, Technikon Natal, 1992. / Brinelling exists ID two fonns, namely true brinelling and false brinelling. Bearing damage due to false brinelling is a common problem and is known to occur on powerstations in Eskom.An example of false brinelling has recently been identified on the ejector pump motors at I.ethabo Pow'er station. True brinelling does not pose a problemto Eskom,and has therefore not been included in this study False brinelling is a special form of fretting and is found to occur in stationary roller element bearings subject to vibration. The vibration creates load fluctuations and varying degrees of relative motion within the bearings. As a result, small depressions or flutes are fonned in the race (Plate 1.1) which eventually lead to increased operational vibration and premature bearing failures. Previous studies do not makeany reference to factors affecting false brinelling in horizontally mounted bearings. The need for a better understanding of false brinelling has increased with the cold storage and partial cold storage of under utilized powerstations. This investigation approachesthe problemof false brinelling froma new angle. Horizontally mountedbearings have been used for testing as opposed to vertically mountedbearings used by other researchers. The effects of static bearing load, impedance,vibration amplitude and direction on false brinelling have been investigated. The study has shown that bearing impedanceand load do not have a significant influence on the rate of bearing damage,while vibration / M

In the drive towards power electronic integration, planar structures are widely used. Applications for the use of these structures are varied. These have been shown to have potential advantages with regard to reduction in size and cost. Much work has been done with regard to integration, but generally from an intuitive perspective, and without a general approach. An important part of power electronic integration is EMI filtering. One way in which this is achieved is through dissipative filtering. It is demonstrated that this can be done for planar structures through the use of multi-layered conductors. Planar conductors have a particularly distinct advantage in that they are low profile and can be miniaturised. The resulting focus of this dissertation is an investigation into the characterisation of two-layer conductors in terms of how the properties of the two layers contribute to the frequency dependent resistance of the conductor. This is done with a direct view towards dissipative filtering. This investigation begins with a description of the method of characterisation of two-layered conductors, and the construction of a parametric study around this. A contribution of this dissertation is the demonstration that the parametric space can be reduced without loss of generality of the characterisation. The results of this characterisation are used to demonstrate the importance of the total conductivity and total permeability as concepts. This concept provides flexibility in the design of two-layer dissipative filters. The concept of a single-layer approximation is presented and investigated. It is shown to even further simplify the model used for multi-layered conductors, and presents a good first level understanding of what the frequency dependent resistance of the structure will be. This concept is shown to be useful in the design of two-layered conductors, and may be generalisable to multiple layers. A second contribution of this work is the presentation of design equations based upon this approximation for five different scenarios. This contribution includes the limits to the dimensions of the two-layer structure, with the conclusion that some specifications do not have physically realisable forms. The final, major contribution that this work presents is as follows. In terms of dissipative filtering, it is shown under differential-mode excitation that the desired properties of the inner layer of the conductor should be: less conductive than the outer layer, and more permeable than the outer layer. These conditions are shown to provide a steeper gradient of resistance increase with respect to frequency. This conclusion is verified experimentally, which provides confidence in the modelling technique this dissertation is based upon.

Thèse : Sciences : Lausanne : 1923. / Bibliographie, p. 107.

Based on the author's thesis, Hochschule für Ökonomie, Berlin. / Includes bibliographical references.

Thesis (M.A.)--Guo li Zheng zhi da xue, 1971. / Cover title. Reproduced from typescript; on double leaves. Bibliography: p. 129.