Engineering Science and Materials Commons^™

Coating Component Migration In Paper Coatings, Emilia Purington

Electronic Theses and Dissertations

In many applications such as in paints and coatings, pigments are mixed with polymeric binders to generate the final product. In the coating of paper, properties like strength, durability, and print quality are affected not only by the binder type, but the final location of the binder relative to the pigments and the fibers. During the application and drying of a paper coating, binder is known to migrate. A number of methods are available to measure the migration of latex or starch. However, all of these methods have some limitations, especially when starch, latex and kaolin are components of the …

Metal Thin Film Stiffness Extraction Technique For Surface Acoustic Wave Filters, Travis R. Weismeyer

Electronic Theses and Dissertations

Accurate knowledge of the surface acoustic wave (SAW) properties propagating at the surface of a piezoelectric substrate with thin films, electrodes or temperature compensated films, is critical in SAW filter design to meet the target frequency response, power durability and performance prior to device fabrication. While reliable material constants exist for substrates such as LiNbO3 used in SAW filters, the absolute elastic constants associated with operational thin films used for electrodes or temperature compensation do not exist. Although the bulk values of the constituent materials are known, the composite film/substrate properties are difficult to predict since they depend strongly on …

Ice Adhesion Analysis Of Severely Aged Pdms Rubbers, Theodore R. Woll

Electronic Theses and Dissertations

The goal of this study was to evaluate and optimize the ice adhesion test initially developed by the University of Denver and to examine Polydimethylsiloxane (PDMS) based silicone rubbers for their ice-phobicity as a function of their physical and chemistry properties, and under severe oxidative aging. The test is based on an ice block bonded to a silicone rubber substrate and subjected to shear. In its original state, the test had severe limitations that caused the ice to be dislodged through a mixture of shear and peeling. Several steps were taken in this research to improve the test, and the …

Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys., Lars Herhold

Electronic Theses and Dissertations

Additive Manufacturing (AM) with metals has been accomplished mainly through powder bed fusion processes. Initial experiments and simulations using Material Extrusion Additive Manufacturing (MEAM) have been performed by various researchers especially using low melting alloys. Recently Stratasys Inc. submitted a patent application for the use of their Material Extrusion technology also called Fused Deposition Modeling (FDM) where they describe the process using thixotropic semi-solid alloys. Currently this process using semi-solid, engineering type alloys such as A356 or THIXALLOY 540 aluminum have not been researched to evaluate the control parameters. This research combines the in-depth knowledge of applying thixotropic semi-solid aluminum …

Microwave Acoustic Saw Resonators For Stable High-Temperature Harsh-Environment Static And Dynamic Strain Sensing Applications, Anin K. Maskay

Electronic Theses and Dissertations

High-temperature, harsh-environment static and dynamic strain sensors are needed for industrial process monitoring and control, fault detection, structural health monitoring in power plant environments, steel and refractory material manufacturing, aerospace, and defense applications. Sensor operation in the aforementioned extreme environments require robust devices capable of sustaining the targeted high temperatures, while maintaining a stable sensor response. Current technologies face challenges regarding device or system size, complexity, operational temperature, or stability.

Surface acoustic wave (SAW) sensor technology using high temperature capable piezoelectric substrates and thin film technology has favorable properties such as robustness; miniature size; capability of mass production; reduced installation …

Ultrasonic Nondestructive Evaluation Of Metal Additive Manufacturing., Venkata Karthik Nadimpalli

Electronic Theses and Dissertations

Metal Additive Manufacturing (AM) is increasingly being used to make functional components. One of the barriers for AM components to become mainstream is the difficulty to certify them. AM components can have widely different properties based on process parameters. Improving an AM processes requires an understanding of process-structure-property correlations, which can be gathered in-situ and post-process through nondestructive and destructive methods. In this study, two metal AM processes were studied, the first is Ultrasonic Additive Manufacturing (UAM) and the second is Laser Powder Bed Fusion (L-PBF). The typical problems with UAM components are inter-layer and inter-track defects. To improve the …

Optimization Of Microfluidic Particle Separator Geometry Using Computational Fluid Dynamics, Joseph Petersen

Electronic Theses and Dissertations

Computational fluid dynamics software was used to simulate the motion of circulating tumor cells in a variety of microfluidic cell isolation devices. Design of several novel microfluidic cell isolation devices was aided by viewing streamlines of fluid in devices in simulation. Devices that performed best in simulation used 5-micrometer wide guiding channels to guide cells to the capture location in the device. While these devices performed better than other devices in simulation and captured all particles regardless of position along inlet, experimental results differ from simulation.

Simulation Of Gas Dynamic Cold Spray Process, Sai Rajkumar Vadla

Electronic Theses and Dissertations

The utilization of computational fluid dynamics (CFD) as a study tool in the aerodynamics and turbomachinery industry reinforces efficiency in the design of aircraft or for understanding the flow through pipes. CFD offer tools to model different geometries and perform a more extensive study of the flow phenomena. This gives the opportunity to model a variety of geometries and analyze their behavior under different operating conditions. A similar approach can be applied to coating technologies. Coating technologies play an essential role in the manufacturing industry. Their ability to form layers of specific materials onto engineering components to enhance mechanical and …

Additive Manufacturing With High Density Polyethylene: Mechanical Properties Evaluation, Calvin Wampol

Electronic Theses and Dissertations

High-density polyethylene is a common recyclable plastic that has a large potential as an additive manufacturing material due its economic and environmental benefits. However, high-density polyethylene has undesirable thermal properties that cause the material to shirk and not adhere to the printing bed during an additive manufacturing processes. Researchers have attempted to combat these thermal properties but have only created novel filaments of high-density polyethylene without being able to create 3D printed specimens for mechanical property testing. This paper presents several methods to create 3D printed specimens with pure high-density polyethylene filament on a fused filament fabrication type 3D printer. …

Structural And Aerodynamic Design, Procedure And Analysis Of A Small V-Shaped Vertical Axis Wind Turbine, Odari J. Whyte

Electronic Theses and Dissertations

Over the last two decades there has been a renewed interest in Vertical Axis Wind Turbines. This turbine configuration though unpopular for large-scale generation has found a niche market in the way of offshore energy harvesting. However, offshore wind has its challenges. In this thesis a detailed comprehensive study of a proposed V-shaped vertical axis turbine rotor is performed in order to examine its structural and aerodynamic characteristics. The design met and exceeded the safety parameters establish for test bed operation, showing a factor of safety of 1.87 with regard to fatigue stress response. A satisfactory fatigue stress design life …