Engineering 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 …

Controls On Phosphorus Export From An Agricultural Watershed: Amsden Brook, Fort Fairfield, Maine Usa., Gregory J. Mcdonald

Electronic Theses and Dissertations

This study explores the sources and mechanisms of phosphorus (P) mobilization during base flow within the Amsden Brook watershed, Fort Fairfield, Maine, USA. Amsden Brook is an agriculturally dominated watershed drained by a spring-fed and perennial first- to second-order stream. We characterized the P concentrations within the watershed to investigate connections between soils, stream sediment, surface water, and groundwater. Waters were monitored monthly during the 2017 snow-free period for temperature, pH, dissolved oxygen, conductivity, soluble reactive P (SRP), total P, strong acid anions, strong base cations, dissolved organic carbon (DOC), Al, Fe, and Mn. Phosphorus speciation within soils and sediment …

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 …

Modeling And Simulation Of The Thermoforming Process In Thermoplastic-Matrix Composite Materials, Philip M. Bean

Electronic Theses and Dissertations

Thermoplastic-matrix composite materials have unique advantages over traditional thermosets including faster processing, improved fracture toughness, and recyclability. These and other benefits have caused increasing interest in the use of these materials in both aerospace and automotive industries. Due to the differences in behavior, these materials require a different type of manufacturing process to thermoset matrix composites. This manufacturing process generally involves using pre manufactured tape-layers. These layers, containing both thermoplastic-matrix and fiber-reinforcement, are aligned to the desired orientation, and stacked up into a “tailored blank” using an automated tape layup machine. They are then heated to the thermoplastic melting temperature …

Development Of Thermoplastic Composite Reinforced Ultra-High Performance Concrete Panels For Impact Resistance, Reagan M. Smith Gillis

Electronic Theses and Dissertations

Recent studies investigating the impact performance of ultra-high performance concrete (UHPC) reported a quasi-brittle flexural failure that transitioned to a brittle punching-shear failure as the size of the impact head was reduced. A potential technology to increase the flexural strength and impact resistance of concrete is applying fiber reinforced polymer (FRP) composites to the exterior faces of the beam or slab. In this work, E-glass fiber reinforced thermoplastics were utilized in two different systems to apply reinforcement to UHPC. Thermoplastic materials were chosen over traditional thermoset materials for their unique advantages, such as rapid fabrication, automated manufacturing and the ability …

Three-Dimensional Bedrock Channel Evolution With Smoothed Particle Hydrodynamics, Nick Richmond

Electronic Theses and Dissertations

Bedrock channels are responsible for balancing and communicating tectonic and climatic signals across landscapes, but it is difficult and dangerous to observe and measure the flows responsible for removing weakly-attached blocks of bedrock from the channel boundary. Consequently, quantitative descriptions of the dynamics of bedrock removal are scarce. Detailed numerical simulation of violent flows in three dimensions has been historically challenging due to technological limitations, but advances in computational fluid dynamics aided by high-performance computing have made it practical to generate approximate solutions to the governing equations of fluid dynamics. From these numerical solutions we gain detailed knowledge of the …

Application Of Silicon Nanohair Textured P-N Junctions In A Photovoltaic Device, Michael Small

Electronic Theses and Dissertations

The goal of this project is to design and develop a fabrication process for a silicon photovoltaic device which incorporates a nanohair textured p-n junction. The silicon nanowires are etched into a silicon wafer, comprising an epitaxial p-layer on n-substrate, via metal-assisted chemical etching (MACE). The resulting nanowires contain p-n junctions that lie along the length of the vertical nanowires. This construct has the potential to increase the optical bandwidth of a silicon photovoltaic device by allowing a greater amount of short wavelength light to reach the junction. In addition, the MACE method of nanofabrication has the potential for decreasing …

Field Implementation Of Tire Derived Aggregate As Lightweight Backfill For Retaining Walls, Jeremy Labbe

Electronic Theses and Dissertations

The objective of this study was to determine the effectiveness of Tire Derived Aggregate (TDA) as embankment and retaining wall backfill material using data from two field projects supplemented by data from previously published studies. Data collected from the two projects included horizontal earth pressure, resultant forces and moments acting in the wall stem, tensile and compressive forces within the wall, moments at the base of the wall, settlement of the TDA, time dependent temperature fluctuations within TDA, pore pressure changes in underlying foundation soil, movement of the wall face, and movement of the embankment. Data Collection was completed by …

Formate Assisted Pyrolysis Of Lignin, Mayank S. Patel

Electronic Theses and Dissertations

A significant fraction of global energy demand is met through nonrenewable petroleum feedstock, which increases the risk of energy security. The energy production from nonrenewable petroleum feedstocks is one of the large contributor to greenhouse gas emissions, which can cause climate change impacts. The energy security can be improved, and the greenhouse gas emissions can be reduced by deriving energy from domestically available renewable lignocellulosic feedstocks such as wood. Wood has three major components: cellulose, hemicellulose, and lignin. The cellulose is primarily used to produce pulp and paper. The hemicellulose is often utilized to produce a valueadded chemical like furfural. …

Feasibility Of Hybrid Thermoplastic Composite-Concrete Load Bearing System, Camerin M. Seigars

Electronic Theses and Dissertations

Thermoplastic composites have many advantages over thermoset composites such as being recyclable, rapidly manufacturable, and more impact resistant. The goal of this thesis is to assess the feasibility of using thermoplastic composites in structural applications through literature review, mechanical testing, design of a load-bearing hybrid composite-concrete structures, and the implementation of thermoplastic composites for tensile reinforcement of concrete. The study had four objectives covering the stated goal.

1. Conduct a literature review to direct thermoplastic material selection
2. Characterize thermoplastic material mechanical properties using standardized mechanical testing
3. Design a hybrid composite-reinforced concrete beam, and
4. Develop thermoplastic shear connectors to develop composite action …

Modeling Coastal Flooding And Sand Transport In The Gulf Of Maine During Severe Storms In A Changing Climate, Dongmei Xie

Electronic Theses and Dissertations

Elevated water level and large waves cause extensive damage and economic loss to coastal communities. An integrated atmosphere-ocean-coast modeling system that links physical processes with scales ranging from the open ocean to the surf zone has been developed for the Gulf of Maine. The modeling system includes a hydrodynamic model, a wave overtopping model and a sediment transport model. It is then applied to investigate and gain a comprehensive understanding of the following coastal processes: (1) the interaction between tide-surge, waves and bathymetry, (2) coastal flooding due to wave overtopping, and (3) sand transport.

Both coastal flooding and sand transport …

Performance Test And Numerical Simulation Of An Adjustable Implant For Treating Vocal Fold Paralysis, Hai Zi

Electronic Theses and Dissertations

Unilateral vocal fold paralysis (UVFP) is one of the most common laryngeal diseases that affect human voice and speech production. It often causes incomplete glottal closure, resulting in voice symptoms including hoarseness, voice fatigue and increased voice effort. One common treatment of UVFP is Thyroplasty Type I, which uses a thyroplasty implant to medialize the paralyzed vocal fold and restore the normal vibration of the vocal fold. However, the surgical outcome is extremely sensitive to the size and shape of the implant. Currently, modifications in the implant size and shape rely upon surgical intuition and experience. The level of voice …

The Hilbert-Huang Transform: A Theoretical Framework And Applications To Leak Identification In Pressurized Space Modules, Kenneth R. Bundy

Electronic Theses and Dissertations

Any manned space mission must provide breathable air to its crew. For this reason, air leaks in spacecraft pose a danger to the mission and any astronauts on board. The purpose of this work is twofold: the first is to address the issue of air pressure loss from leaks in spacecraft. Air leaks present a danger to spacecraft crew, and so a method of finding air leaks when they occur is needed. Most leak detection systems localize the leak in some way. Instead, we address the identification of air leaks in a pressurized space module, we aim to determine the …

Mechanistic Studies Of Reducible Metal Oxides As Hydrodeoxygenation Catalysts, Akbar Mahdavi Shakib

Electronic Theses and Dissertations

Hydrodeoxygenation of phenol to benzene using ruthenium supported titania catalysts strongly varies depending on the support crystal structure and preparation conditions. Here, we performed spectroscopic characterization of titania supports to identify the surface impurities common to commercial and synthesized titania samples using a variety of spectroscopic methods. Sulfate impurities were detected for the commercial anatase samples and a procedure for their elimination was proposed so that inactive catalysts gained reactivity. Surface hydroxyls of different TiO2 samples (anatase, rutile, and pyrogenic) were identified using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments performed on vigorously cleaned surfaces and a facet-specific assignment …

How Gpu Rendering Affects Image Processing And Scientific Calculation Speed, Power And Energy On A Raspberry Pi, Qihao He

Electronic Theses and Dissertations

In this thesis, we explore the speed, power, and energy performance of the same data process on the central processing unit (CPU) with and without the acceleration of the Graphics Processing Unit (GPU) on the microcomputer Raspberry Pi (RPI). We tested on the RPI in two different fields. The first was comparing the speed, power, and energy usage with and without GPU acceleration in the image processing impacts on RPI model B+. The second was comparing speed, power, energy usage, and accuracy for scientific calculation with and without GPU acceleration on RPI model B+ and 3B.

We used a novel …

Developing A Risk Assessment Protocol To Quantify Distribution And Uptake Of Persistent Organic Pollutants In Glacial Outflows, Kimberley Rain Miner

Electronic Theses and Dissertations

Pollutants released by industrialized nations between 1960 and 2004 have been transported northward through atmospheric processes and deposited into glaciated alpine ecosystems. Many of these chemicals retain their original structure and are absorbed into the biota thousands of miles away from where they were originally utilized. With a warming climate increasing the melt of alpine glaciers, these glaciers may be introducing growing amounts of toxins into the watershed. While studies have demonstrated the existence of resident pollutants within glaciated ecosystems, no one has developed a risk assessment to identify sources and quantity of risk posed by these compounds when released …

The Dynamics Of Mixing And Subtidal Flow In A Maine Estuary, Kristopher Bears

Electronic Theses and Dissertations

Long-term material transport in estuaries is largely controlled by subtidal flow. Subtidal flows are driven by conditions specific to their geographic location, namely river discharge, tidal forcing, and wind. These conditions are further modified by mixing, curvature of the estuary, Coriolis, and friction. While many practices of measuring these various forcing mechanisms exist, the current literature fails to provide a standard for measuring turbulent mixing in well- mixed estuaries. As a changing climate affects these various forcing and modifying mechanisms via sea level rise and increased precipitation, the corresponding material transport scheme is expected to change accordingly. Subtidal flow and …

Wireless Sensor System For Mild Cognitive Impairment Diagnosis, Ahmed A. Almaghasilah Mr

Electronic Theses and Dissertations

Alzheimer’s disease (AD), which causes decline in the cognitive functions, is the

major lead of dementia. AD begins showing damage in memory, making patients

dependent on caregivers. Treating AD requires early diagnosis of its signs. The

initial sign of AD is mild cognitive impairment (MCI), which is the middle stage

between a healthy patient and one diagnosed with AD. The proposed sleep

monitoring system is capable of diagnosing MCI symptoms.

MCI patients are characterized with sleep fragmentation and sleep disorder. The

sleep fragmentation is defined as awakenings that interrupt the normal sleep. The

proposed system in this thesis uses force …

Stochastic Modeling Of Wireless Energy Transfer With Applications In Wireless Displacement Sensing Of Structures, Shaun G. Veilleux

Electronic Theses and Dissertations

Wireless communications are being utilized in nearly every field of work and impact virtually everyone's daily life. With the increased use of wireless sensors, the difficulty of powering them becomes more apparent. One emerging technology is the use of wireless energy transfer which utilizes either a designated transmitter or harvests otherwise wasted energy. Since the amount of transferable wireless energy is limited modeling and simulating a system's probability of operation is desired in order to maximize the run time of the sensor. These simulations allow for the investigation into the impact of a smart scheduling algorithm that can determine the …

Evaluation Of Non-Composite Steel Girder Bridges Using Field Load Testing And A Calibrated Finite-Element Model, Mahmood J. Albraheemi

Electronic Theses and Dissertations

This research focuses on understanding the behavior of five, non-composite, simple-span steel girder bridges using field load testing and calibrated finite element models. These bridges were tested during the summer of 2016. Strains and selected displacements were measured at multiple locations during the field load tests. 3D finite-element (FE) models were created to simulate the actual response of these bridges with a novel approach to calibrate these models was developed that captures the observed full and partial composite action as well as rotational restraint of the girder ends. More accurate predictions of the bridges capacity were determined using field tests. …

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 …

Surface Reaction And Diffusion Kinetics In Semiconducting Metal Oxide Film Gas Sensors, Aravind Reghu

Electronic Theses and Dissertations

Chemiresistive metal oxide gas sensors based on materials such as SnO₂, ZnO, and TiO₂, have been investigated extensively by many researchers for a wide range of applications. The band bending model, based on the surface chemistry of highly reactive ionosorbed species (O₂^- or O^-) and the semiconducting material properties of SnO₂, TiO₂ and ZnO, adequately predicts the dependence of the change in sensor conductivity (Δσ) as a function of target gas pressure and temperature. However, the band bending model is not applicable to gas sensors based on reducible oxides …

Detailed Power Measurement With Arm Embedded Boards, Yanxiang Mao

Electronic Theses and Dissertations

Power and energy are becoming important considerations in today's electronic equipment. The amount of power required to run a supercomputer for an hour could supply an ordinary household for many months. The need for low-power computing also extends to smaller devices, such as mobile phones, laptops and embedded devices.

In order to optimize power usage of electronic equipment, we need to collect information on the power consumption of these devices. Unfortunately it is not easy to do this on modern computing systems. Existing measuring equipment is often expensive, inaccurate, and difficult to operate. The main goal of this project is …