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Full-Text Articles in Mechanical Engineering
On The Degradation Of Lubricating Grease, Asghar Rezasoltani
On The Degradation Of Lubricating Grease, Asghar Rezasoltani
LSU Doctoral Dissertations
A comprehensive literature review on physical and chemical degradation monitoring and life estimation models for lubricating greases is presented in chapter one. Degradation mechanisms for lubricating grease are categorized and described, and an extensive survey of the available empirical and analytical grease life estimation models including degradation monitoring standards and methods are presented. In chapter two, irreversible thermodynamic theory is employed to study the mechanical degradation of lubricating grease. A correlation between the mechanical degradation and entropy generation is established and the results are verified experimentally using a rheometer, a journal bearing test rig, and a modified grease worker machine. …
Thermophysical And Thermochemical Property Measurement And Prediction Of Liquid Metal Titanium Alloys With Applications In Additive Manufacturing, Jonathan Richard Raush
Thermophysical And Thermochemical Property Measurement And Prediction Of Liquid Metal Titanium Alloys With Applications In Additive Manufacturing, Jonathan Richard Raush
LSU Doctoral Dissertations
Accurate high-temperature thermophysical property data for liquid metals and alloys are important for simulation of laser-based 3D printing processes. To understand and better control such additive manufacturing processes, knowledge of density, viscosity, and surface tension of liquid metals and alloys versus composition and temperature is needed. Likewise, thermochemical property data information regarding alloys, including chemical activities and free energies relative to composition and temperature, aid in the understanding and development of phase data important in the material design process. Vacuum electrostatic levitation (ESL) is an important technique through which both thermophysical and thermochemical property measurements can be accomplished without physical …
Design Of Surface Texture For The Enhancement Of Tribological Performance, Cong Shen
Design Of Surface Texture For The Enhancement Of Tribological Performance, Cong Shen
LSU Doctoral Dissertations
Surface texturing is a method of surface modification that fabricates micro patterns on the contacting surfaces to improve the tribological performance in sliding, lubricated system. It is found that the geometric design of textures has a significant influence on the performance of textured surfaces. Some important geometric parameters, such as the area ratio and the depth-over-diameter ratio, have been identified for textures in the form of circular dimples. The current study aims to improve the friction reduction effect of surface texturing by using textures with novel designs. Some new factors considered in the design of textures are: internal structure and …