Nanoscience and Nanotechnology Commons^™

Fabrication, Characterization, And Simulation Of Graphene-Copper Electrical Conductors, Raju Prasad Ghimire

Nanoscience and Microsystems ETDs

The addition of nanocarbons to copper (Cu), specifically in the form of graphene (GN), has been shown to enhance copper's properties. GN-Cu nanocomposites can potentially achieve higher electrical, mechanical, and thermal properties compared with copper. These characteristics make GN-Cu materials interesting for several applications including but not limited to interconnects, high voltage lines, and rotating machines. Copper’s microstructure and nanoscale interfacial phenomena between the GN and Cu control charge conduction in GN-Cu materials. In this work, we investigated the possibilities of conductivity enhancement in multi-layered GN-Cu composites both theoretically (classical, quantum, and atomistic models) and experimentally.

Additionally, our work elucidates …

Characterization Of Materials Properties In Additively Manufactured Aisi-420 Martensitic Steel Deposited By Laser Engineered Net Shaping, Md Mehadi Hassan

Nanoscience and Microsystems ETDs

Metal additive manufacturing (AM) is a disruptive technology enabling the fabrication of complex and near-net-shaped parts by adding material layer-wise. It offers reduced lead production time. AM processes are finding applications in many industrial sectors such as aerospace, automotive, biomedical, and mold tooling. Despite the tremendous advantages of AM, some challenges still prevent this technology's adoption in high-standard applications. Anisotropy and inhomogeneity in the mechanical properties of the as-built parts and the existence of pores and lack-of-fusion defects are considered the main issues in directed energy deposition (L-DED) parts. Laser-engineered net shaping LENS® offers excellent possibilities to fabricate metal tools …

Material Characterization And Comparison Of Sol-Gel Deposited And Rf Magnetron Deposited Lead Zirconate Titanate Thin Films, Katherine Lynne Miles

Mechanical Engineering ETDs

Lead zirconate titanate (PZT) has been a material of interest for sensor, actuator, and transducer applications in microelectromechanical systems (MEMS). This is due to their favorable piezoelectric, pyroelectric and ferroelectric properties. While various methods are available to deposit PZT thin films, radio frequency (RF) magnetron sputtering was selected to provide high quality PZT films with the added capability of batch processing. These sputter deposited PZT films were characterized to determine their internal film stress, Young’s modulus, composition, and structure. After characterization, the sputtered PZT samples were poled using corona poling and direct poling methods. As a means of comparison, commercially …

Control Mechanisms For Adaptive Nanoscale Devices, David Arredondo

Nanoscience and Microsystems ETDs

Nanotechnology promises to revolutionize many areas of applied science including materials, synthetic biology, and medicine. Devices may consist of solution-phase information processing systems or molecular robots. Of particular interest are DNA-based systems due to their composability and relatively simple interactions that are suited to bottom-up design. This work introduces high-level designs of robust control mechanisms for nanoscale devices with immediate applications in molecular computing, synthetic biology, and DNA robotics.

Nanoscale systems are dominated by probabilistic chemical behavior, so engineers must take careful consideration to produce predictable systems. Probabilistic behavior in chemical reaction networks (CRNs) yields deterministic evolution of species concentrations …

Physiologically-Based Pharmacokinetics Modeling Of Colloidal Nanoparticles, Anh-Dung Le

Nanoscience and Microsystems ETDs

Physiologically-based Pharmacokinetics (PBPK) modeling—a mechanistic mathematical tool to predict biodistribution to inform drug development, requires knowledge of the physico-chemical properties of the drug in question as well as the anatomy and physiology of the organism. Unlike with molecular drugs, nanoparticle parameters often need to be estimated by fitting models to time-course data, which can result in large uncertainties in parameter estimates due to a high-dimensional parameter space. Our research addresses this challenge by offering a path to parameter insights using global sensitivity analysis. The first chapter is an overview of the PBPK model structure and mathematical framework used in our …

Fabrication And Characterization Of Carbon Nanotube Metal Matrix Composites For Use In Photovoltaic Gridline Applications, Cayla M. Nelson

Nanoscience and Microsystems ETDs

Performance reliability is crucial for photovoltaic (PV) cells in both terrestrial and space-based applications. Electrical efficiency losses over time are heavily impacted by electrical losses due to microcracks within the cell structure and metallization failure. Mechanical stresses and thermal cycling of the device can lead to fracture of the current-carrying metal (Ag) lines on the surface of the device, significantly reducing output power. Incorporating carbon nanotubes (CNTs) into PV metal lines as a reinforcement, forming a CNT/Ag metal matrix composite (MMC), enhances the electrical and mechanical performance of the device. In this work the influence of CNT/Ag MMCs were explored …

Application Of Bismuth Oxychloride As A Colorimetric Uv Sensor Material, Kyle James Troche

Nanoscience and Microsystems ETDs

Sunlight contains about 9% UV radiation with roughly one-third of it penetrating the atmosphere and reaching the Earth’s surface. UV radiation from the sun is classified into three different types: UVA (315- 499 nm), UVB (280- 314nm), and UVC (100- 279 nm). Prolonged exposure to artificial UV radiation or direct sunlight can still induce many adverse effects such as sunburn, weakening of the immune system, and skin cancer. A wide variety of photoresistor, photodiode and colorimetric UV sensors are currently being researched to help monitor UV radiation. Our research is focused on developing a colorimetric UV sensor that is inherently …

Surface Acoustic Wave Characterization And Interdigitated Transducer Optimization For Studying Stress-Enhanced Phenomena, Brian D. Rummel

Nanoscience and Microsystems ETDs

Surface acoustic wave devices have not yet achieved their full potential as the effects of standing acoustic fields on stress-sensitive phenomena in semiconductor systems have been largely unexplored. From this perspective, it is necessary to develop novel methods to characterize surface acoustic wave devices quantitatively and prepare an experimental platform to probe stress-enhanced processes. In this dissertation, interdigitated transducer devices are fabricated on gallium arsenide to evaluate their potential impact on strain-enhanced phenomena. A novel Raman characterization technique characterizes the surface stress induced by a standing acoustic field, revealing stress values on the order of 10⁸ Pa. FEM software …

Enhancing Optical And Thermal Properties Of Nanofibrous Films Inspired By The White Beetle Scale, Bokyung Park

Nanoscience and Microsystems ETDs

The Cyphochilus white beetle has received significant attention recently for its exceptional visible-light-scattering properties, owing to the beetle scale's anisotropic nano-fibrillar network structure. Inspiration from the remarkable optical properties of these biological species has directed research efforts to fabricating biomimetic nano-fibrillar structures with polymer materials. In this work, electrospun silk fibroin polymer films reproduce the white beetle scale's anisotropic nature to draw on its optical scattering properties and further improve the radiative-cooling capabilities of silk fabrics. An anisotropically restructured silk film with a mean fiber diameter of a few hundred nanometers substantially increases optical scattering strength in the visible spectrum …

Controlling The Emission Of Volatile Platinum Oxides To The Vapor Phase In Diesel Oxidation Catalysts, Arnab Ghosh

Nanoscience and Microsystems ETDs

Pt-based catalysts are used for the treatment of emissions from vehicles, particularly in Diesel oxidation catalysts (DOCs). Three-way catalysts are treated at temperatures ranging from 950℃-1050℃ while DOCs are aged at 800℃ for 50 hrs. At 800°C, Pt reacts with O₂ to form PtO₂ which has a high vapor pressure and can be transported through the vapor phase. These accelerated aging conditions lead to the formation of large Pt particles causing a loss of catalytic activity. In this thesis, we used model thin-film catalysts that made it possible to quantify the emission of Pt to the vapor phase …