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Full-Text Articles in Mechanical Engineering

An Examination Of The Indentation Size Effect In Fcc Metals And Alloys From A Kinetics Based Perspective Using Nanoindentation, David Earl Stegall Oct 2016

An Examination Of The Indentation Size Effect In Fcc Metals And Alloys From A Kinetics Based Perspective Using Nanoindentation, David Earl Stegall

Mechanical & Aerospace Engineering Theses & Dissertations

The indentation size effect (ISE) in metals is described as the rise in hardness with decreasing depth of indentation and contradicts conventional plasticity behavior. The goal of this dissertation is to further examine the fundamental dislocation mechanisms that may be contributing to the so-called indentation size effect. In this work, we examined several metals and alloys including 99.999% Aluminum (SFE ~200 mJ/m2), 99.95% Nickel (SFE ~125 mJ/m2), 99.95% Silver (SFE ~22 mJ/m2), and three alloys, alpha brass 70/30 (SFE >10 mJ/m2), 70/30 nickel copper (SFE ~100 mJ/ …


Electrokinetic Phenomena In Pencil Lead-Based Microfluidics, Yashar Bashirzadeh, Venkat Maruthamuthu, Shizhi Qian Jan 2016

Electrokinetic Phenomena In Pencil Lead-Based Microfluidics, Yashar Bashirzadeh, Venkat Maruthamuthu, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

Fabrication of microchannels and associated electrodes to generate electrokinetic phenomena often involves costly materials and considerable effort. In this study, we used graphite pencil-leads as low cost, disposable 3D electrodes to investigate various electrokinetic phenomena in straight cylindrical microchannels, which were themselves fabricated by using a graphite rod as the microchannel mold. Individual pencil-leads were employed as the micro-electrodes arranged along the side walls of the microchannel. Efficient electrokinetic phenomena provided by the 3D electrodes, including alternating current electroosmosis (ACEO), induced-charge electroosmosis (ICEO), and dielectrophoresis (DEP), were demonstrated by the introduced pencil-lead based microfluidic devices. The electrokinetic phenomena were characterized …