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A Transmission Electron Microscopy Study Of Defect Generation And Microstructure Development In Ultrasonic Wire Bonding, Nikhil Mohan Murdeshwar

Doctoral Dissertations

Ultrasonic wire bonding is widely used in the electronic industry to connect semiconductor chips to packages. Even though the popularity of the technique has increased in recent times, questions remain about the bonding mechanism, and factors affecting bondability and reliability. In this thesis, answers were provided to many of these questions using TEM to examine bonded cross section and plan view specimens.

A detailed investigation of the Al wire and substrate showed dynamically annealed well recovered grains while microstructural observations of other substrates revealed wide varieties of response mechanisms. For example, Ni formed a dislocation cell structure, Cu formed a …

Performance Of Concrete Beams And Slabs Reinforced With Frp Grids, Edwin Robert Schmeckpeper

Doctoral Dissertations

The objective of this dissertation was to evaluate the suitability of Fiber Reinforced Plastic (FRP) grids for use as a structural reinforcement in concrete structures such as highway bridge decks. The work concentrated on determining the mechanical properties of FRP materials, testing the flexural behavior and servicability of concrete beams and slabs reinforced with FRP grids, and determining splice and development length requirements for FRP grids. Design recommendations concerning failure mode, deflections, anchorage requirements were developed.

The results from the flexural tests on FRP reinforced concrete beams, with reinforcing ratios ranging from 0.3% to 2.2%, showed that the failure mode, …

Corrosion Protection Of Metals By Poly(3-Methylthiophene) Coatings, Shouxian Ren

Doctoral Dissertations

Electrochemically prepared poly(3-methylthiophene) (P3MT) films were used as conductive polymer coatings to poise a substrate metal in the passive potential range in corrosive media. To firmly adhere P3MT coatings onto substrate metals, different methods were developed for each metal; stainless steel (430SS), titanium (TiGr2) and carbon steel (C1010). The samples were either pretreated by anodization in phosphate solution to form a uniform porous surface or pitted by chloride ions simultaneously with the formation of an adhesive thin film. Coatings were characterized for various galvanostatic electropolymerization conditions on both platinum and phosphated 430SS (Ph430SS) rotating disk electrodes (RDEs). Both applied current …