Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 139-142).

Thesis (Ph. D.)--University of Hong Kong, 1990.

Thesis (M.S.)--University of North Texas, Dec., 2008. / Title from title page display. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vi, 106 p. : ill. Includes abstract. Includes bibliographical references (p. 75-76).

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1935. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 9, 2010) Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 80-83).

Blends of lubricant base stocks are commonly employed to produce lubricants with optimised performance. However, the influence of blending on lubricant behaviour within high pressure, mechanical contacts, particularly the film forming capacity and friction, have largely gone unstudied. This thesis examines both of these aspects for a range of base fluids and their blends. Film thickness generation and fluid friction are reviewed in the context of elastohydrodynamic (EHD) lubrication. Various models addressing the origin and mechanism of liquid viscosity are reviewed. The derivation of viscosity as a thermodynamic property is also reviewed and its relevance to the current study is discussed. Consideration is also given to two commonly accepted yet contrasting models of EHD traction, resulting in one being adopted for this research. The relationship of molecular structure to film generation is examined experimentally by studying a number of single component fluids with widely varying chemical structures. It is shown that pressure-viscosity coefficients derived from film thickness are strongly related to the respective chemical “family” of the lubricant. EHD friction (traction) measurements are also made and analysed in order to establish a reliable method for comparing the influence of fluid composition on traction. The method, based on a well regarded fluid model, allows accurate description of full fluid traction by means of the Eyring stress and pressure-viscosity coefficient in the central EHD contact. Binary blends of well-defined base fluids are studied. It is found that the pressure- viscosity coefficient, as derived by the aforementioned methods, varies nonlinearly with the composition and tends toward the lower value of the individual components, at times attaining values lower than either of the individual components.

A high-traction fluid is one of the vital components of a traction drive; a mechanism where input power is transformed into an output force when pressure and shear force are applied to the fluid. In this environment they need to withstand high pressures, temperatures and shear forces, and must be able to lubricate at the same time. So far there has been very little research relating engineering performance to molecular structure. Previous work with model hydrocarbon traction fluids has shown that molecular rigidity about the centre of the molecule appears to be important. This work has now been extended to cyclohexyl esters. A series of cyclohexyl esters was synthesised, and where possible, x-ray structures were obtained. Extensive 13C T1 and NOE relaxation data over a range of radiofrequencies and temperatures were obtained and used to calculate correlation times, for both overall and internal motion, using both the "model-free" and reduced Lorentzian models. This provided information on the rigidity of the molecules studied, In addition molecules have been modelled using molecular dynamics techniques to calculate order parameters and torsion angle distributions. ESR studies have been conducted to measure the viscosity of each fluid. A spin probe, with a similar structure to one of the molecules studied, was synthesised. This allowed complimentary correlation time measurement, and showed that the molecule rotated isotropically. Difficulties were encountered in fitting the NMR data to the motional models and the need for higher radiofrequency data is indicated, to check the validity of the models used. The NMR, ESR and molecular dynamics results did, however, provide a consistent indication of the differing rigidities and motions of these molecules.

Solid lubricants possessing low friction coefficients, low wear rates, and long wear lives are vital for significantly increasing the life span of instruments undergoing extreme frictional wear due to harsh environments. Solid lubricants currently used in high temperatures or excess humidity, such as MoS2, WS2, graphite, or noble metals, are unable to sustain superior frictional qualities over extended amounts of time or in changing environments. To ameliorate these limiting properties, a composite solid lubricant is produced to enable the favorable frictional properties of one lubricant to overcome the lacking frictional properties of the other. This composite uses the combined materials to produce a solid lubricant that can sustain a low friction coefficient and wear rate for a longer amount of time than each individual material. MoS2 electrodeposited on to carbon nanotubes (CNTs) has a lower friction coefficient in humid (~0.16), non-humid (~0.05) and non-humid/humid cycled (~0.075-0.2) environments than either bare MoS2 or bare CNTs. Similarly, silver deposited on CNTs, by electrodeposition, electroless deposition, and sputter coating, performs better in room temperature, high temperature (500°C), and room temperature/high temperature cycling environments than either of its individual materials. Using the techniques used to produce these solid lubricant composite coatings with appealing frictional properties will provide a variety of tribological applications involving high temperature and/or high humidity environments with necessary solutions and further facilitate the improvement of solid lubricants used in other extreme environments.