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Full-Text Articles in Tribology

Tribological Studies Of Thick Polytetrafluoroethylene Coatings Enhanced By Polydopamine And Nanoparticles, Sujan Kumar Ghosh Jul 2021

Tribological Studies Of Thick Polytetrafluoroethylene Coatings Enhanced By Polydopamine And Nanoparticles, Sujan Kumar Ghosh

Graduate Theses and Dissertations

Polytetrafluoroethylene (PTFE) is a popular low friction solid lubricant with high chemical and thermal stability. Thick PTFE coatings have the potential for many tribological applications, such as replacing Tin-based Babbitt materials in journal bearings. However, the weak bonding strength to the substrate and the high wear rate of PTFE coatings are current limiting factors. The lack of understanding of their tribological properties and wear mechanisms in oil-lubricated conditions and how coating thickness affects the tribological performance further hindered the use of PTFE coatings. In this dissertation, polydopamine (PDA), a bio-inspired adhesive, is used as an underlayer for or as a …


High Temperature Degradation In Gan-Based Hall Effect Sensors, Alexis Anne Krone Jul 2021

High Temperature Degradation In Gan-Based Hall Effect Sensors, Alexis Anne Krone

Graduate Theses and Dissertations

This research focuses on understanding the effects of accelerated aging through temperature and environment on novel gallium nitride-based Hall effect magnetic field sensors and determining device reliability under electric vehicle operating conditions. The device reliability was modeled using accelerated aging for the temperatures of 200 °C, 350 °C, 450 °C, and 600 °C under various time steps unique to each temperature and either air, which is identical to operating circumstances, or argon, which would model the hermetic packaging environment. Using a high temperature furnace and oven, devices underwent high temperature storage tests at a chosen temperature and time step. Afterwards, …


Modeling Of Mixed Friction Interactions Occurring In Axial Piston Pumps, Andrew C. Adelsperger, Lizhi Shang, Dan Mizell, Monika Ivantysynova Aug 2014

Modeling Of Mixed Friction Interactions Occurring In Axial Piston Pumps, Andrew C. Adelsperger, Lizhi Shang, Dan Mizell, Monika Ivantysynova

The Summer Undergraduate Research Fellowship (SURF) Symposium

Axial piston pumps are integral to a variety of hydraulic systems due to their versatility and reliability, but most attempts to model them for design purposes have failed. However, software which fully models the fluid structures within these pumps, such as the FSTI gap design program, has improved significantly. Unfortunately, current discrepancies between simulated and measured friction forces on the cylinder due to the fluid drag and piston movement need to be eliminated so that more accurate simulation of these pumps in operation is possible. Friction measurements and FSTI simulation outputs were analyzed with MATLAB filters and graphs, resulting in …


Basins Of Attraction Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, Reza Montazami Jan 2009

Basins Of Attraction Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, Reza Montazami

Nastaran Hashemi

We perform a large number of simulations over a wide range of system parameters to approximate the basins of attraction of steady oscillating solutions. We find that the basins of attraction vary as a function of system parameters and initial conditions. For large equilibrium separations, the basin of attraction is dominated by the low-amplitude solution. The location of the fixed point is shifted toward the higher values of instantaneous displacement and velocity for larger equilibrium separations. We show that the basin of attraction in the neighborhood of the fixed point is dominated by low-amplitude solutions as relative humidity is increased.