This thesis investigates potential materials to be used in the rotary sealing industry that provide low power loss and minimize cost. The studied rotary valve utilizes slots that act as timing valves to allow for flow axially, through the seal face, at particular times within a heat pump cycle. This investigation examines various combinations of multiple PTFE materials, plastics, and soft metals that have been proven to provide low friction coefficients. Leakage and wear requirements are stated for the future use of the rotary valve and are used to determine the effectiveness of sealing the fluid while examining the power loss. In conclusion, the study finds the combination of a modified PTFE stationary ring and Aluminum Bronze rotating face to provide the lowest power loss. Numerical analysis was completed to verify the lubrication regime to be partial lubrication and was also used to investigate geometry changes and impact on the power loss.

The mechanical grinding processes is the most popular way to fabricate the end face of optical fibers, although there are some other methods like chemical etching and leaser machining. In cases of fabricate the wedge type and wedge-cone type optical fiber end faces, the mechanical grinding is the typical way. Professor Y. C. Tsai¡¦s research group has successfully fabricated the optical fiber with elliptical-cone-type end-face in a single grinding process by adopting a mechanism with eccentric mass on the commercial optical fiber grinding machine. In this study, a torque motor is equipped on the commercial optical fiber grinding machine for controlling the normal pressure between the optical fiber and the grinding film during the grinding process. While the optical fiber rotating, the normal pressure, as well as the material removed rate and the final shape of the optical fiber, can be controlled in different periodical mode shapes by applying different voltages with different periodical mode shapes. The merit of this system is its capability of fabricating fiber with elliptical-cone-shape and polygon-cone-shape (polyhedron-tip) end faces in a single grinding process that will increase the efficiency and the accuracy of grinding. It is believed the grinding machine system developed in this study can be successfully applied for fabricating the optical fiber lenses as well as different types of micro probes for other applications.