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Molten Aluminum Capillary Hole-Filling, Cheng-Nien Yu

Theses and Dissertations--Mechanical Engineering

The presence of micrometeoroids and space debris in open space raises the question of a mitigation of the damage caused by a possible impact on the man-made structures such as space shuttles, satellites, and the International Space Station. A method achieving metallic sealed hole would be of an interest for development. This dissertation studies a surface tension driven capillary filling/sealing phenomenon in a controlled atmosphere brazing process of aluminum. The filled vs. non-filled results are predictable using minimization of energy, which shows that the outcomes depend heavily on prescribed configurations of the hole. Equilibrium models show excellent agreement with experimental …

Scalable Patterning Using Laser-Induced Shock Waves, Saidjafarzoda Ilhom, Khomidkhodza Kholikov, Peizhen Li, Claire Ottman, Dylan Sanford, Zachary Thomas, Omer San, Haluk E. Karaca, Ali O. Er

Mechanical Engineering Faculty Publications

An advanced direct imprinting method with low cost, quick, and minimal environmental impact to create a thermally controllable surface pattern using the laser pulses is reported. Patterned microindents were generated on Ni₅₀Ti₅₀ shape memory alloys and aluminum using an Nd: YAG laser operating at 1064 nm combined with a suitable transparent overlay, a sacrificial layer of graphite, and copper grid. Laser pulses at different energy densities, which generate pressure pulses up to a few GPa on the surface, were focused through the confinement medium, ablating the copper grid to create plasma and transferring the grid pattern onto …

Summary Of Experimental Bridge Features, Theodore Hopwood Ii, James H. Havens, Edgar E. Courtney

Kentucky Transportation Center Research Report

Experimental bridge features and service problems investigated during this study are reviewed. Those were epoxy-coated reinforcing steel, stay-in-place forms, experimental deck features (rotary compaction and broomed deck finishing), precast segmental bridges, steel-corrosion control methods (weathering steel and hot-dipped galvanizing), microsilica concrete, failures of masonry coatings, and failures of aluminum guardrail-retaining nuts.

Several features including latex and low-slump overlays, epoxycoated reinforcing steel, and broomed deck finishes (for state-built bridges), are now in common use. Most of the other experimental bridge features were performing satisfactorily. A corrosion problem was observed on one weathering steel bridge. Analyses of failures of masonry coatings and …