Engineering Commons^™

Characterization And Restoration Of Historic Rosendale Cement Mortars For The Purpose Of Restoration, Stephanie Hart

All Theses

Mortar was a very common building material in today's historic sites. Before Portland cement was manufactured at a global level, Rosendale cement was commonly used in these mortars. Over time, these mortars in historic sites have begun to break down and wear away. With Rosendale cement in production again, measures can be taken to restore and repair the historic mortars. However, little testing has been done to establish durability of modern Rosendale cement mortars. This presentation highlights the common mix techniques used at the time, and undergoes experiments to establish general properties and predict future durability. Six different mortar mixes …

Determination Of A Higher-Order Elastic Constant Of A Single Filament Of Hextow Im7-12k Carbon Fiber Using Finite Deformations, Luciana Oliveira

All Theses

The modulus of elasticity of a homogeneous body is the same for all directions. No known crystalline materials have a Young's modulus that is the same in all directions. The linear theory of elasticity states that strain is proportional to stress so that a straight line is obtained in a stress versus strain plot. As long as the forces applied to the body are proportional, the body behaves perfectly elastically, obeying Hooke's law. At high enough strains, however, deviations from Hooke's law will occur. Nonlinear elasticity is generally apparent when large deformations are applied and usually when the sample size …

Preliminary Investigation Into The Design Of Thermally Responsive Forster Resonance Energy Transfer Colloids, Monte Bedford

All Theses

While nuclear imaging techniques (Magnetic Resonance Imaging, Computed Tomography, and Positron Emission Tomography) have proven effective for diagnosis and treatment of disease in the human body, fluorescence-enhanced optical imaging offers additional benefits. Fluorescent imaging provides high resolution with real-time response, persistent lifetime (hours to days), cell targeting, and transdermal penetration with minimal physical encumbrance. Malignant cells can be targeted by absorbance of exogenous fluorescent nanoprobe contrast agents. Imaging is improved by fluorescent enhancement, especially by energy transfer between attached dyes. Also for use against cancer are heat-active treatments, such as hyperthermal, photothermal, and chemothermal therapies. Helpful to these treatments is …

Double Paddle Oscillators For The Mechanical Spectroscopy Of Ion-Solid Interactions, Jason Puls

All Theses

We demonstrated using a double paddle oscillator to measure subsurface defect formation at room temperatures caused by ion implantation. This sensor has a low amount of noise based because of its high quality factors in certain modes. The double paddle oscillator was bombarded with Ar ions under ultra-high vacuum conditions while it was oscillating. The resultant resonant frequency changes were discussed as a method to determine defect formation inside the bulk substrate.

Measuring Ligand Exchange On The Surface Of Gold Nanoparticles: A Study Of Competitive Binding Of Ligands Utilizing Fluorescent Resonance Energy Transfer, Daniel D'Unger

All Theses

This study was conducted to track ligand exchange on the surface of metallic nanoparticles in order obtain a better understanding of binding strength of various functional groups. This study develops groundwork for further understanding ligand exchange as nanoparticles transition from engineered to natural systems. A problem exists in knowing the fate of these particles if they are released into natural systems, by accident or with intent. To gain a better understanding of what may occur we look at the binding strength of different ligands. This is done to gain knowledge of the possibility of displacement of ligands occurring in the …

Deformation And Adhesion Of Thin Metallic Films On Flexible Substrates, Julia Reid

All Theses

Flexible electronics are conductive circuits, components and lines integrated onto elastic substrates. These systems often consist of metallic thin films deposited onto thin sheets of glass, metals stainless steel or polymeric materials such as polyethylene or polystyrene. These systems are currently being studied for a wide variety of aeronautic and astronautical applications including: electronic skins, solar sails, and antennae structures. For applications include only moderately elevated temperatures (near 200 ¡C) and low strains (insert range), engineers have proposed incorporation metallic lines onto polymeric substrates. Like traditional microelectronic systems with films on hard substrates, the reliability is controlled by the film-substrate …

Optimization Of Processing Parameters For As2se3 Glass For Low Loss, High Strength Fibers, Baptiste Giroire

All Theses

Chalcogenide glasses have been widely studied due to their extraordinary transparency in the infrared (IR) region from 0.5 to 20 μm. This transparency combined with excellent thermo-mechanical properties, makes them ideal candidate for infrared optics including IR fiber optic applications. However, such non-oxide glasses generally exhibit low mechanical strength, as compared to their oxide counterpart, which are based on covalently bonded metal-oxygen species. In addition to mechanical robustness, low optical loss (hence low impurity content) is required for most IR optical materials, including the one in this study, amorphous arsenic tri-selenide, As2Se3. In this effort, As2Se3 glass was investigated and …

Tribiology Of Engineered Surfaces In Aggressive Environments, Nathan Phillip Mitchell

All Theses

To improve the performance of sliding systems, surface modifications and coatings are often applied to opposing surfaces. This thesis focuses on characterizing two tribo-systems (DLC-DLC and steel micropatterns-flat) under their predicted application environments. The first section is focused on friction testing of micropatterned surfaces for orthopaedic device design, the second section elucidates how the sliding of diamond-like-carbon (DLC) coatings changes with temperature and humidity. The experimental design and major results of these sections are as follows.

(1) The use of micropatterning to create uniform surface morphologies has been cited as yielding improvements in the coefficient of friction during high velocity …

Nanoparticles In Solution-Derived Chalcogenide Glass Films, Spencer Novak

All Theses

The results in this thesis are from our efforts to modify the optical properties of solution-derived chalcogenide glass films by the incorporation of nanomaterials. First, the composition Ge23Sb7S70 was selected as the appropriate glass matrix for testing because solution-derived films of this composition have been well-studied in our group. Additionally, this composition was found to be less sensitive to certain processing parameters than As2S3, another well-studied, candidate chalcogenide glass composition, making Ge23Sb7S70 more suitable for the addition of nanomaterials. Optimization of film process parameters was performed to obtain high-quality films appropriate for doping with nanomaterials. This consisted of determining the …

Characterization And Optimization Of Solution-Derived Chalcogenide Glass Thin Films, Jacklyn Wilkinson

All Theses

Chalcogenide glasses have many unique properties that allow them to be used in a variety of optical applications. Infrared transparency allows them to be used in sensors for molecules that have 'fingerprints' in the 2-25 μm range. By producing amorphous thin films of these materials, they can be incorporated into chemical sensors as planar waveguides and resonators. The goal of this work was to fabricate and characterize solution-derived chalcogenide thin films for use in chemical sensors with a source wavelength between 3-3.5 μm.
The structural and optical properties of the parent bulk glass were characterized and used as reference for …

Surface Characterization Of Nephila Clavipes Dragline Silk, Benoit Faugas

All Theses

To design synthetic fibers for extreme applications, many research groups are trying to identify how the structure of natural fibers (such as spider silk) leads to desirable properties such as high tensile strength.
Spider silk is a biological fiber having mechanical properties that exceed those of the best man made fibers in terms of high tensile strength and large extensibility, this combination providing the silk with a large work of rupture. While the bulk structure, composition and properties have been intensively studied elsewhere, this study focuses on elucidating the Nephila clavipes spider dragline silk surface structure and composition, as well …