No description available.

No description available.

This research investigates the tribological performance of crystalline and amorphous powders of boron as additives in lubricants: grease and mineral oil for potential applications of wind turbine. This research is focused on the wear resistance and lubricity performance of boron powders. Experimental approach was used in this research. Several experiments were conducted including API RP 7A1 thread compound test, pin-on-disk tribometer experiment, stribeck curve analysis and surface analysis. It is possible to obtain fundamental principles of boron powder as additives in lubricants from these experiments. The results indicate that amorphous boron powder is beneficial for lubricants additive, while crystalline boron powder showed that it is not proper as an additive, since there were a lot of traces of abrasive wear. According to the results amorphous boron powder provided anti-wear and better lubricity properties in the lubricants. The observation and understanding obtained here will be beneficial for the lubrication industry. This research will provide basic principle of boron powder and possibilities of boron powder as additive in lubricants. This thesis is composed of six chapters. The first chapter is about general ideas of lubrication from problems to emulsion techniques, followed by chapter II, motivation and objectives. Chapter III provides experimental details including boron powder’s properties and basic information will also be discussed in this chapter. Finally obtained results will be discussed in the chapter IV and V followed by chapter VI conclusions and future recommendations.

No description available.

No description available.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 69-72).

[No abstract available] / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

The' 'thermal wedge' effect in hydrodynamic lubrication has been studied both theoretically - and experimentally. The friction theory has been refined to take into consideration the effect on friction of a variation of temperature across the film from the bearing to the disk surface. The theoretical pressure and temperature equations formulated by Currie were used in conjunction with the friction equation to obtain theoretical performance curves. Tests were carried out on a set of bearings having three, four and five pad configurations. Two different bearing materials were used, namely, babbitt, and Delrin A.F. fiber/resin. Circumferential oil rings were fitted into the assembly to restrict the radial flow of oil, thereby ensuring full lubrication of the bearings. Experimental observations proved that a thermal gradient across the film did exist, thus justifying the basic assumption in the variable viscosity analysis. Experimental coefficients of friction compared favourably with predicted values. The agreement was better than by-earlier theories. The results indicate that bearing performance is improved by the use of oil restrictor rings (actual load carrying capacities were more than doubled). The optimum bearing .configuration was that of a four-pad babbitt bearing. Although the Delrin A F bearing performed much better than the babbit bearings, differential thermal expansion of the Delrin produced a geometric wedge, and a bearing of this material could not be considered-as a thermal wedge bearing. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

No description available.

No description available.