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Full-Text Articles in Mechanical Engineering

Using Dielectric Scatters To Selectively Excite Embedded Eigenstates In Cavity Resonators, Olugbenga Joshua Gbidi Jan 2023

Using Dielectric Scatters To Selectively Excite Embedded Eigenstates In Cavity Resonators, Olugbenga Joshua Gbidi

Theses and Dissertations

Bound states in the continuum (BICs) are waves that remain in the continuous spectrum of radiating waves that carry energy, however, still localized within the spectrum. BICs, also embedded eigenmodes, exhibit high quality factors that have been observed in optical and acoustic waveguides, photonic structures, and other material systems. Presently, there are limited means to select these BICs in terms of the quality factor and their excitation. In this work, we show that a different type of BIC, Quasi-BICs (Q-BICs), in open resonators can have their quality attuned by introducing embedded scatters. Using microwave cavities and dielectric scatters as an …


Investigation Of Polymer Nanocomposites With Silicon Dioxide Fillers As Helium Cooled High-Temperature Superconducting Cable Dielectrics, Jordan Thomas Cook Oct 2022

Investigation Of Polymer Nanocomposites With Silicon Dioxide Fillers As Helium Cooled High-Temperature Superconducting Cable Dielectrics, Jordan Thomas Cook

Theses and Dissertations

In this thesis, three polymer nanocomposite configurations are fabricated for investigation as dielectrics in helium-cooled high-temperature superconducting (HTS) cables. Polyimide, polyamide, and polymethyl methacrylate are utilized as host polymers. The composite samples are synthesized through an in situ process, dispersing silicon dioxide nanoparticles throughout the polymer hosts. Fourier transform infrared spectroscopy and scanning electron microscopy were employed to validate the synthesis of each composite configuration. Thin film samples of each configuration were also tested for their dielectric strength at both room (300 K) and cryogenic (92 K) temperatures. When going from room to cryogenic temperatures, all materials demonstrated a significant …


Perovskite Solar Cells Fabricated Via Scalable Dip Coating Methods, Joseph F. Iannello May 2018

Perovskite Solar Cells Fabricated Via Scalable Dip Coating Methods, Joseph F. Iannello

Theses and Dissertations

Perovskite solar cells present the possibility for less expensive electricity generation, through the use of low cost materials and fabrication methods relative to current silicon-based technology. Many current methods of fabricating thin film perovskite solar cells focus on spin-coating, which inherently lacks scalability due to particle conglomeration, poor uniformity over a larger area, and safety concerns. Dip-coating, an alternative to spin-coating, which is explored here addresses these issues which limit scalability. Each individual layer can be separately synthesized, deposited, and characterized, which leads towards scalability. Choosing only the best results from each independent layer allowed progress to the creation of …