Engineering Commons^™

Performance And Durability Of Electrodes With Platinum Catalysts In Polymer Electrolyte Cells Prepared By Ultrasonic Spray Deposition, William A. Rigdon

Theses and Dissertations

Catalysts in the electrodes of polymer electrolyte cells serve a critical function in reactions which can be used to either generate electrical energy from chemical fuels or convert electrical energy into chemicals. For low temperature electrochemical fuel cells, platinum is often utilized for its exceptional catalytic activities towards hydrogen oxidation and oxygen reduction reactions of the anode and cathode, respectively. However, the limited supply of platinum and high demand result in prohibitive costs plaguing commercialization of this technology. Therefore, minimal amounts of the catalyst should be used to achieve the maximum output to reduce expenses. Electrochemical behavior is governed by …

Polymer Nano-Dielectrics For High Density Energy Storage, Sayful Islam Md

Theses and Dissertations

Military and commercial users require next-generation polymer dielectric materials for pulse power and power conditioning applications with rise times less than 1 ms and AC power at frequencies ranging from kHz to MHz. These power density and rate capability requirements necessitate the use of dielectric capacitors that store energy via polarization of electrons in molecular scale dipoles. Multiphase polymer composites and all-polymer dielectrics could be new kinds of materials to meet this acute need for capacitors with compact size and high rate capability.

The polymer nanocomposite (PNC) approach to achieve high energy density employed a “colossal” dielectric constant material, calcium …

An Adaptive Educational Game To Help Students Learn How To Solve Systems Of Linear Equations, Wang Zhang

Theses and Dissertations

Educational games have been proven to be effective in developing problem solving skills in well-defined domain, such as Math and Physics. In this thesis, an educational game called Matrix was developed to foster problem solving skills in the domain of linear algebra, particularly solving a system of linear equations. Matrix is an adaptive educational game that uses intelligent tutoring modules to guide the student's learning process and provide feedback based on the student's performance. These modules are domain module, student module, pedagogical module and presentation module. The domain module contains all the concepts the student needs to learn and an …

Conflict Management And Model Consistency In Multi-User Cad, Ammon Ikaika Hepworth

Theses and Dissertations

The NSF Center for e-Design, Brigham Young University (BYU) site has re-architected Computer Aided Design (CAD) tools, enabling multiple users to concurrently create, modify and view the same CAD part or assembly. This technology allows engineers, designers and manufacturing personnel to simultaneously contribute to the design of a part or assembly in real time,enabling parallel work environments within the CAD system. Multi-user systems are only as robust and efficient as their methods for managing conflicts and preserving model consistency. Conflicts occur in multi-user CAD when multiple users interoperate with the same or dependent geometry. Some conflicts can lead to model …

System Identification Of An Unmanned Tailsitter Aircraft, Nathan W. Edwards

Theses and Dissertations

The motivation for this research is the need to improve performance of the autonomous flight of a tailsitter UAV. Tailsitter aircraft combine the hovering and vertical take-off and landing capability of a rotorcraft with the long endurance flight capability of a fixed-wing aircraft. The particular aircraft used in this research is the V-Bat, a tailsitter UAV with a conventional wing and the propeller and control surfaces located within a ducted-fan tail assembly. This research focuses on identifying the models and parameters of the V-Bat in hover and level flight as a basis for the design of the control systems for …

Sediment Transport Conditions Near Culverts, Kyle Jay Rowley

Theses and Dissertations

Relatively little work has been done to understand how coarse grained sediments behave near culverts. Particularly for embedded culverts, sediment transport must be understood to achieve sustainable culvert designs for aquatic organism passage and peak discharge requirements. Several culvert sites in the Wasatch Mountains of Utah were studied through the spring flood season of 2014. Data obtained from the culvert sites were used to create numerical models with the Sedimentation and River Hydraulics Two-Dimensional model. The field sites and numerical model were used to study deposition of sediments at the entrance to culverts, sediment replenishment inside culverts, and lateral fining …

Refinement And Characterization Of Synthetic Vocal Fold Models, Shelby Charisse Ward

Theses and Dissertations

Understanding vocal fold mechanics is an integral part of voice research and synthetic vocal fold models are an essential tool in characterizing vocal fold mechanics. These models contain multiple layers with varying stiffness, much like human vocal folds. The purpose of this thesis is to improve the current models and modeling techniques, as well as investigate the impact of asymmetry on model vibration. A new design for an MRI-based model is detailed. This model has a more realistic geometry than the simplified models and mimics some of the vibratory characteristics observed in human vocal folds. The MRI-based model was used …

Source Apportionment Of Wastewater Using Bayesian Analysis Of Fluorescence Spectroscopy, Daniel B. Blake

Theses and Dissertations

This research uses Bayesian analysis of fluorescence spectroscopy results to determine if wastewater from the Heber Valley Special Service District (HVSSD) lagoons in Midway, UT has seeped into the adjacent Provo River. This flow cannot be directly measured, but it is possible to use fluorescence spectroscopy to determine if there is seepage into the river.Fluorescence spectroscopy results of water samples obtained from HVSSD lagoons and from upstream and downstream in the Provo River were used to conduct this statistical analysis. The fluorescence 'fingerprints' for the upstream and lagoon samples were used to deconvolute the two sources in a downstream sample …

Effect Of High Percentages Of Reclaimed Asphalt Pavement On Mechanical Properties Of Cement-Treated Base Material, Jacob Clark Tolbert

Theses and Dissertations

Full-depth reclamation (FDR) is an increasingly common technique that is used to rehabilitate flexible pavements. Implementation of FDR on rehabilitation projects produces several desirable benefits. However, these benefits are not fully realized due to the fact that state department of transportation specifications typically limit the reclaimed asphalt pavement (RAP) content of pavement base material to 50 percent. The objective of this research was to evaluate the effects of RAP content, cement content, temperature, curing time, curing condition, and moisture state on the strength, stiffness, and deformation characteristics of cement-treated base (CTB) mixtures containing high percentages of RAP.For this research, one …

Verifying Molecular Dynamics Using Dielectric Spectroscopy, Joshua Dee Smith

Theses and Dissertations

The electrical properties of proteins in solution are important for their structure and function. Computational biophysics studies of proteins need accurate parameters to ensure that numerical simulations match physical reality. Past work in this eld has compared the electrical properties of proteins obtained from dielectric spectroscopy to numerical simulations of proteins in water with adjustment of pKa values to try to capture the inevitable changes in electrical conformation that will occur in a complex structure such as a folded protein. However, fundamental veri cation of the charge parameters of the amino acid building blocks in common molecular dynamics software packages …

An Investigation Of Project Delivery Methods Relating To Repetitive Commercial Construction, Donald A. Patterson

Theses and Dissertations

The Design/Bid/Build (DBB) delivery method has historically been the most popular and the most effective means of determining the least cost for building a project based upon a set of construction documents. In recent years, however, other project delivery methods, including but limited to Construction Manager/General Contractor (CM/GC) and Design/Build (DB), have slowly taken a share of the construction market away from the DBB delivery method. The choice of delivery method that will produce the best value for an owner in the measurements of efficiency in quality, cost, and timeliness depends upon the type of project and the business culture …

Investigation Of Compaction Characteristics Of Subbase Material Using The Superpave Gyratory Compactor, Craig Kumpel

Theses and Dissertations

The purpose of this study is to complete an in-depth analysis of data from both the Federal Aviation Administration's (FAA) full-scale testing and Superpave Gyratory Compactor testing to determine if the SGC is a valuable tool for the prediction of airport pavement performance and design. The practicality of the SGC was based on extensive laboratory and field testing of three unbound materials including P-154, P-209, and DGA, which are the subbase and base materials used by the FAA at the National Airport Pavement Test Facility (NAPTF). During the past construction cycles at the NAPTF, it has been found that the …

Creating Total Value Engineering Through Combining Design For Manufacturing And Design For Six Sigma Constructs, David Ryan Christensen

Theses and Dissertations

The modern manufacturing world has been driven to compete in a more international and interconnected system. This has led to increased focus upon frameworks and architectures to guarantee quality, high market acceptance, and reduce cost. Modern manufacturing design processes evolved largely from Henry Ford at Ford Motor Company, and Alfred Sloan at General Motors. Their structures embody two different focuses on quality and value engineering which have influenced many recent design frameworks. In the 1970s a heavy emphasis was placed upon Design for Manufacturing, which uses group technology, commonality of processes, and continual focus to reduce part count. Some companies …

Design And Analysis Of Receiver Systems In Satellite Communications And Uav Navigation Radar, Matthew Robertson Morin

Theses and Dissertations

The design of a low cost electronically steered array feed (ESAF) is implemented and tested. The ESAF demonstrated satellite tracking capabilities over four degrees. The system was compared to a commercial low-noise block downconverter (LNBF) and was able to receive the signal over a wider angle than the commercial system. Its signal-to-noise ratio (SNR) performance was poor, but a proof of concept for a low cost ESAF used for tracking is demonstrated. Two compact low profile dual circularly polarized (CP) reflector feed antenna designs are also analyzed. One of the designs is a passive antenna dipole array over an electromagnetic …

A Model For Analyzing Heating And Cooling Demand For Atria Between Tall Buildings, Samuel David Christensen

Theses and Dissertations

The heating and air-conditioning energy demand of skyscrapers with atria between buildings is explored. Radiation, conduction, convection, and ventilation were evaluated to determine annual heating and cooling energy demands for a 100-building city located in Provo, Utah. Spreadsheets models were developed and calibrated with a computational fluid dynamics model. Three spreadsheet model cases were examined: a baseline no-atrium case, a conditioned atrium case, and an unconditioned atrium case. The energy demands and atrium temperatures were compared between the different cases. The research concludes that atria can be used between buildings to reduce the heating and cooling energy demands. The exposed …

Recursive-Ransac: A Novel Algorithm For Tracking Multiple Targets In Clutter, Peter C. Niedfeldt

Theses and Dissertations

Multiple target tracking (MTT) is the process of identifying the number of targets present in a surveillance region and the state estimates, or track, of each target. MTT remains a challenging problem due to the NP-hard data association step, where unlabeled measurements are identified as either a measurement of an existing target, a new target, or a spurious measurement called clutter. Existing techniques suffer from at least one of the following drawbacks: divergence in clutter, underlying assumptions on the number of targets, high computational complexity, time-consuming implementation, poor performance at low detection rates, and/or poor track continuity. Our goal is …

In-Plane Lateral Load Capacities Of Vertically Oriented Interlocking Timber Panels, Brandon T. Decker

Theses and Dissertations

The Vertically Oriented Interlocking Timber (VOIT) panel is a new solid wood panel similar to Interlocking Cross Laminated Timber (ICLT) and the more commonly known Cross Laminated Timber (CLT). Like ICLT, VOIT panels use timber connections instead of the adhesives or metal fasteners common to CLT. The difference of VOIT is the orientation of the layers. Where CLT and ICLT panels alternate the orientation of each layer, VOIT panels orient all the layers in the same direction. The vertically oriented layers are then attached to one another by smaller horizontal dovetail members.Two types of VOIT panels were provided to be …

Analysis And Compression Of Large Cfd Data Sets Using Proper Orthogonal Decomposition, Trevor Jon Blanc

Theses and Dissertations

Efficient analysis and storage of data is an integral but often challenging task when working with computation fluid dynamics mainly due to the amount of data it can output. Methods centered around the proper orthogonal decomposition were used to analyze, compress, and model various simulation cases. Two different high-fidelity, time-accurate turbomachinery simulations were investigated to show various applications of the analysis techniques. The first turbomachinery example was used to illustrate the extraction of turbulent coherent structures such as traversing shocks, vortex shedding, and wake variation from deswirler and rotor blade passages. Using only the most dominant modes, flow fields were …

Development Of A Complex Synthetic Larynx Model And Characterization Of The Supraglottal Jet, Jayrin Ella Seegmiller

Theses and Dissertations

Voice is an important tool for communication. Consequently, voice disorders tend to severely diminish quality of life. Voice research seeks to understand the physics that govern voice production to improve treatment of voice disorders. This thesis develops a method for creating complex synthetic laryngeal models and obtaining flow data within these complex models. The method uses Computed Tomography (CT) scan data to create silicone models of the larynx. Index of refraction matching allows flow field data to be collected within a synthetic complex larynx, which had previously been impossible. A short proof-of-concept of the method is set forth. Details on …

Airline Consumers’ Perception Of Transport Security Administration’S Prohibited Items, Clayton Ernest D'Souza

Theses and Dissertations

There has been limited research conducted and significantly limited scholarly articles on consumer attitudes towards the current TSA prohibited items list. If the research were to be conducted a year after the September 11, 2001 attacks, the results of the research would be negatively skewed, indicating the majority of passengers would approve of the TSA prohibited list. But after almost thirteen years since the devastating act of terrorism and no major attempt to repeat a similar terrorist activity, would airline consumers continue to fly if the TSA amended the prohibited items list and allowed passengers to bring on liquids and …

Measurement And Modeling Of Fire Behavior In Leaves And Sparse Shrubs, Dallan R. Prince

Theses and Dissertations

Wildland fuels and fire behavior have been the focus of numerous studies and models which provide operational support to firefighters. However, fuel and fire complexity in live shrubs has resulted in unexpected and sometimes aggressive fire behavior. The combustion of live fuels was studied and modeled, and the results were assimilated into a shrub-scale fire behavior model which assumes fire spread by flame-fuel overlap. Fire spread models have usually assumed that radiation heat transfer is responsible for driving fire spread, but that assumption is a topic of continuing debate, and appears to contradict some experimental observations. A convection-based shrub-scale fire …

Validity And Reliability Of A Mini Situational Judgment Test (Sjt) For Pilots, Lu Shi

Theses and Dissertations

The situational judgment test (SJT) was developed by Hunter (2002) to test pilot judgment. SJT is very useful. However, this test takes too long for participants to complete. A mini SJT was developed with shortened questions. The purpose of this research was to determine the reliability and validity of mini SJT comprised of 16 of the original 51 questions. Validity and reliability were the two key elements in psychometrics. Face validity was used as a method to measure validity. Reliability was determined by Cronbach's Alpha, the correlation of split half and even odd, and Pearson s correlation of test retest. …

Characterization Of Sinusoidal Vibration Induced Fluid Motion In Spherical Elastomeric Diaphragm Tanks, Cody Ambrose Harris

Theses and Dissertations

Elastomeric diaphragm tanks are commonly used in spacecraft applications to incite positive expulsion of hydrazine monopropellant. The diaphragm exhibits low flexural rigidity, causing it to easily fold under its own weight at low fill levels. If the tank is sinusoidally oscillated under standard gravity, such as during ground transportation or launch pad winding, these folds will result in rubbing, eventually wearing down the thin material to the point of failure. The ability to accurately predict the presence of folds, rubs, and center of gravity shifts for a given tank design and frequency excitation is thus of critical importance to mission …

Analysis Of Data Center Network Convergence Technologies, Robert-Lee Daniel Leblanc

Theses and Dissertations

The networks in traditional data centers have remained unchanged for decades and have grown large, complex and costly. Many data centers have a general purpose Ethernet network and one or more additional specialized networks for storage or high performance low latency applications. Network convergence promises to lower the cost and complexity of the data center network by virtualizing the different networks onto a single wire. There is little evidence, aside from vendors' claims, that validate network convergence actually achieves these goals. This work defines a framework for creating a series of unbiased tests to validate converged technologies and compare them …

Elastic Energy Absorption Via Compliant Corrugations, Sean S. Tolman

Theses and Dissertations

Elastic absorption of kinetic energy and distribution of impact forces are required in many applications. This may be achieved through the use of compliant corrugations. An innovative padding concept is investigated for such applications. Also, recent attention given to the potential for using origami in engineering applications may provide new corrugation configurations that are advantageous for energy absorption and force distribution. This work explores three areas related to these concepts.First, the parameters of a compliant, corrugated padding concept are investigated using Finite Element Analyses (FEA) and physical testing. The shape of the corrugation cross section is explored as well as …

The Effect Of Learning And Cost Optimization On Line Of Balance Scheduling, Kareem Essam Zahran

Theses and Dissertations

The increase in populations throughout the past years introduced the need for improving and increasing countries’ infrastructure. Moreover, there has been an increasing demand for dwelling units ranging from small economic housing blocks to high-rise buildings and residential villa compounds. These projects are known by their repetitive nature, where a constant unit is repeated several times. Scheduling techniques that consider the learning effect as an influencing parameter in calculating productivity rates can improve the effectiveness of the scheduling process. This achieves more realistic forecasts resulting in optimum utilization of resources and better control during implementation phases. Linear scheduling techniques are …

Automated Landing Site Determination For Unmanned Rotocraft Surveillance Applications, Justin Keith Mackay

Theses and Dissertations

Unmanned air vehicles have been increasing in their autonomous capabilities. This research furthers these capabilities by focusing on the automation of landing site determination for rotorcraft in urban environments. Automated landing saves energy and allows the aircraft to choose areas that are safe for people and the aircraft. Two methods are used to gather information about the terrain of potential landing sites. One method is 3D reconstruction from multiple camera images. The other method uses a range sensor to reconstruct the terrain. Both of these methods create an inertial terrain map of the environment in the form of a point …

Articulated Spine For A Robot To Assist Children With Autism, Brandon M. Norton

Theses and Dissertations

Autism spectrum disorder (ASD) affects about 1.5 million individuals in the US alone. The consequences of ASD affect families, caregivers, and social structures. This thesis adds to a growing group of people performing research on mitigating the effects of autism through robotics. Children with ASD tend to interact with robots more easily than with other humans. The goal of robotic therapy is not to help children interact with robots, but to generalize the behavior to humans. An articulated spine is a key to human emotional expression through shaping, weight shifting, and flow. Despite this importance, this feature is all but …

Passive Force On Skewed Bridge Abutments With Reinforced Concrete Wingwalls Based On Large-Scale Tests, Kyle Mark Smith

Theses and Dissertations

Skewed bridges have exhibited poorer performance during lateral earthquake loading when compared to non-skewed bridges (Apirakvorapinit et al. 2012; Elnashai et al. 2010). Results from small-scale laboratory tests by Rollins and Jessee (2012) and numerical modeling by Shamsabadi et al. (2006) suggest that skewed bridge abutments may provide only 35% of the non-skewed peak passive resistance when a bridge is skewed 45°. This reduction in peak passive force is of particular importance as 40% of the 600,000 bridges in the United States are skewed (Nichols 2012). Passive force-deflection results based on large-scale testing for this study largely confirm the significant …

A Computational Hybrid Method For Self-Intersection Free Offsetting Of Cad Geometry, Garrett Clark Bodily

Theses and Dissertations

Surface offsetting is a valuable tool used in Computer Aided Design (CAD). An offset surface is a collection of points that are at a constant distance from another surface. An offset surface is created in CAD by selecting a surface and then specifying the distance that the surface is to be offset. If a surface is selected and a distance of D is specified, then the resulting offset surface should always be distance D from the original surface. The surface offset tool can be used for many applications. Modeling of composites or other layered manufacturing processes rely heavily on offset …