Other Materials Science and Engineering Commons^™

Zirconium Diboride, Hexagonal Boron Nitride, And Amorphous Alumina Thin Films For High Temperature Applications, David Murdock Stewart

Electronic Theses and Dissertations

The use of microelectronic sensors and actuators in harsh, high temperature environments, such as power plants, turbine engines, and industrial manufacturing, could greatly improve the safety, reliability, and energy efficiency of these processes. The primary challenge in implementing this technology is the breakdown and degradation of thin films used in fabricating these devices when exposed to high temperatures >800 °C and oxidizing atmospheres. Zirconium diboride, hexagonal boron nitride, and amorphous alumina are candidate materials for use as thin film sensor components due to their high melting temperatures and stable phases. Zirconium diboride thin films have metallic-like electrical conductivity and remain …

Creation And Evaluation Of Polymer/Multiwall Carbon Nanotube Films For Structural Vibration Control And Strain Sensing Properties, Weiwei Lin

FIU Electronic Theses and Dissertations

Multifunctional materials both with damping properties and strain sensing properties are very important. They promise to be more weight-efficient, and provide volume-efficient performance, flexibility and potentially, less maintenance than traditional multi-component brass-board systems.

The goal of this dissertation work was to design, synthesize, investigate and apply polyaniline/Multiwall carbon nanotube (PANI/MWCNT) and polyurethane (PU) /MWCNT composites films for structural vibration control and strain sensors using free layer damping methods and static and dynamic strain sensing test methods.

The PANI/MWCNT was made by in situ polymerization of PANI in the presence of MWCNT, then frit compression was used to make circular and …

Modelling And Simulation Of The Flexoelectric Effect On A Cantilevered Piezoelectric Nanoplate, Xining Wang

Electronic Thesis and Dissertation Repository

Piezoelectric nanomaterials have attracted increasing attentions due to their distinct electromechanical features, especially the size-dependent properties, which differ greatly from their bulk counterparts.

Due to the large strain gradients presented in nanostructures, the flexoelectricity is believed to be responsible for such size-dependent properties. In this thesis, based on the Kirchhoff plate model and the extended linear piezoelectric theory, a modified continuum mechanics based model is developed to study the size-dependent flexoelectric effect upon the static bending behaviors of a cantilevered piezoelectric nanoplate (PNP). Finite difference method (DFM) is employed to obtain the approximate numerical solutions.

The numerical results indicate that …

Lignin-Based Li-Ion Anode Materials Synthesized From Low-Cost Renewable Resources, Nicholas William Mcnutt

Doctoral Dissertations

In today’s world, the demand for novel methods of energy storage is increasing rapidly, particularly with the rise of portable electronic devices, electric vehicles, and the personal consumption and storage of solar energy. While other technologies have arguably improved at a rate that is exponential in accordance with Moore’s law, battery technology has lagged behind largely due to the difficulty in devising new electric storage systems that are simultaneously high performing, inexpensive, and safe.

In order to tackle these challenges, novel Li-ion battery anodes have been developed at Oak Ridge National Laboratory that are made from lignin, a low-cost, renewable …

Enzyme Stabilization In Hierarchical Biocatalytic Food Packaging And Processing Materials, Dana Erin Wong

Doctoral Dissertations

The partnership of biocatalysts and solid support materials provides many opportunities for bioactive packaging and bioprocessing aids beneficial to the agricultural and food industries. Biocatalysis, or reactions modulated by enzymes, allows bioactive materials to assist in bringing a substrate to product. Enzymes are proteins which catalyze reactions by lowering the activation energy required to drive the production of a desired product. Enzymes are commonly utilized in food processing as catalysts with specificity in order to enhance product quality through the production of beneficial food components, and to break down undesirable components that may be harmful or may decrease product quality. …

Advanced Electrode Materials By Electrostatic Spray Deposition For Li-Ion Batteries, Chunhui Chen

FIU Electronic Theses and Dissertations

Recent development in portable electronics and electric vehicles have increased the demand for high performance lithium ion batteries. However, it is still challenging to produce high energy and high power lithium ion batteries. The major objective of this research is to fabricate advanced electrode materials with enhanced power density and energy density. Porous Li4Ti5O12 (LTO) and its nanocomposites (with Si and reduced graphene oxide (rGO)) synthesized by electrostatic spray deposition (ESD) technique were mainly studied and promising electrochemical performance was achieved. In chapter 3, porous LTO thin film electrode was synthesized by ESD to solve the low energy density and …

Dynamic Atomistic Study Of Tunnel Functions In Nanostructured Transitional Metal Oxides, Yifei Yuan

Dissertations, Master's Theses and Master's Reports

Alpha (α-) MnO₂ is a well know transitional metal oxide possessing one dimensional 2×2 (4.6 × 4.6 Ų) tunnels for accommodation of various ions. Such a characteristic tunneled structure has enabled the wide applications of α-MnO₂ in the fields of ion exchange, molecular sieves, biosensor, catalysis and energy storage. This PhD dissertation focuses on the dynamic study of ion transport functionality of α-MnO₂ at atomic level using an aberration corrected scanning transmission electron microscopy equipped with a special holder with a scanning tunneling microscopy probe.

The wide application of in situ TEM studying the dynamic …

Diagnostics And Degradation Investigations Of Li-Ion Battery Electrodes Using Single Nanowire Electrochemical Cells, Naveen Kumar Reddy Palapati, Naveen Kumar Reddy Palapati

Theses and Dissertations

Portable energy storage devices, which drive advanced technological devices, are improving the productivity and quality of our everyday lives. In order to meet the growing needs for energy storage in transportation applications, the current lithium-ion (Li-ion) battery technology requires new electrode materials with performance improvements in multiple aspects: (1) energy and power densities, (2) safety, and (3) performance lifetime. While a number of interesting nanomaterials have been synthesized in recent years with promising performance, accurate capabilities to probe the intrinsic performance of these high-performance materials within a battery environment are lacking. Most studies on electrode nanomaterials have so far used …