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Graduate Theses and Dissertations

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Full-Text Articles in Engineering

Addressing Multi-Bit Errors In Dram/Memory Subsystem, Ravikiran Yeleswarapu Jan 2020

Addressing Multi-Bit Errors In Dram/Memory Subsystem, Ravikiran Yeleswarapu

Graduate Theses and Dissertations

As DRAM technology continues to evolve towards smaller feature sizes and increased densities, faults in DRAM subsystem are becoming more severe. Current servers mostly use CHIPKILL based schemes to tolerate up-to one/two symbol errors per DRAM beat. Such schemes may not detect multi-symbol errors arising due to faults in multiple data buses and/or chips. In this work, we introduce Single Symbol Correction Multiple Symbol Detection (SSCMSD) - a novel error handling scheme to correct single-symbol errors and detect multi-symbol errors. Our scheme makes use of a hash in combination with Error Correcting Code (ECC) to avoid silent data corruptions ...


Overcoming The Limitations Of Commodity Augmented Reality Head Mounted Displays For Use In Product Assembly, Jack Miller Jan 2019

Overcoming The Limitations Of Commodity Augmented Reality Head Mounted Displays For Use In Product Assembly, Jack Miller

Graduate Theses and Dissertations

Numerous studies have shown the effectiveness of utilizing Augmented Reality (AR) to deliver work instructions for complex assemblies. Traditionally, this research has been performed using hand-held displays, such as smartphones and tablets, or custom-built Head Mounted Displays (HMDs). AR HMDs have been shown to be especially effective for assembly tasks as they allow the user to remain hands-free while receiving work instructions. Furthermore, in recent years a wave of commodity AR HMDs have come to market including the Microsoft HoloLens, Magic Leap One, Meta 2, and DAQRI Smart Glasses. These devices present a unique opportunity for delivering assembly instructions due ...


Innovative Studies On Reinforced Concrete Panel Structures Through Experimental Testing And Finite Element Modeling; And Teaching Structural Engineering Courses Using Augmented Reality, Elizabeth Miller Jan 2019

Innovative Studies On Reinforced Concrete Panel Structures Through Experimental Testing And Finite Element Modeling; And Teaching Structural Engineering Courses Using Augmented Reality, Elizabeth Miller

Graduate Theses and Dissertations

This thesis presents the results of three studies conducted within the field of structural engineering during completion of a master’s thesis. The first two studies report on the results of experimental testing and finite element modeling in reinforced concrete structures. Both structures can be thought to be composed of concrete panels. The third study, while not related to experimental work, details results of an in-classroom experiment utilizing an application developed to transform typical teaching pedagogy utilizing augmented reality.

The first study focuses on a particular detail utilized within the connection of an approach slab to bridge deck. Known as ...


Collaborative Product Review Using Virtual Reality Interface Devices Performance Studying, Mihir Radia Jan 2019

Collaborative Product Review Using Virtual Reality Interface Devices Performance Studying, Mihir Radia

Graduate Theses and Dissertations

The study presents two research questions: 1) Can stereoscopic 3-D visualization (like Virtual Reality) improve a design reviewer’s ability to detect errors when reviewing a product model over a traditional CAD system in which 3D product models are viewed on a flat 2D computer screen? 2) Can two collaborating individuals be more effective (faster time or detect more errors) during a product design review than one individual operating alone? The answer to the first question will help provide product design reviewers, managers, and software designers in product design firms decide what features to include, and whether it is worthwhile ...


Performance Archery Shooting, Hunter Sabers Jan 2019

Performance Archery Shooting, Hunter Sabers

Graduate Theses and Dissertations

Bows and arrows can be traced all the way back to 65,000 BC and have evolved from a tool used for hunting, to a tool for war, and today used by hobbyists in competition. The evolution of this technology has progressed for the most part without an understanding of the effect it has on humans. The present study aims to connect how technology effects humans specifically looking at archery. The study measured the muscle activity in the bow arm of the archer and the vibration experienced on the bow arm of the archer during the shooting process. From those ...


Probe Vehicle Performance Measures For Assessing Travel Time Reliability, Kyle Robert Thompson Jan 2019

Probe Vehicle Performance Measures For Assessing Travel Time Reliability, Kyle Robert Thompson

Graduate Theses and Dissertations

Travel time reliability reflects the degree to which the amount of time needed for a trip is predictable. Metrics that quantify travel time reliability are emerging as a fundamental part of assessing the performance of transportation networks. Many states and municipalities are starting to incorporate travel time reliability into their transportation assessments and planning processes. Probe vehicle data is a prevalent data source which can be utilized to compute many of these travel time reliability metrics. This study used probe vehicle data from INRIX to compute, compare, and apply travel time reliability metrics on interstate segments in Iowa. It also ...


Airline Fleet Planning And Utilization Hours Comparison Studies, Daniel Zhou Jan 2019

Airline Fleet Planning And Utilization Hours Comparison Studies, Daniel Zhou

Graduate Theses and Dissertations

After the latest mechanical malfunction accidents involving Allegiant and Southwest Airlines, a special interest was taken to investigate whether low-cost carriers (LCC) are taking an overly aggressive stance in regards to the utilization of aircraft within their respective fleets. Based on summary reports obtained from incident logs generated by the FAA (Federal Aviation Administration) and NTSB (National Transportation Safety Board), it was observed that Allegiant Airlines was almost three and a half times as likely to encounter a mid-air breakdown as legacy carriers are. On the economic front, the fallout that Southwest Airlines has faced from the Flight 1380 incident ...


Design And Rapid Prototyping Of Printed Graphene Electrochemical Biosensors For Sensitive Monitoring Of Pesticide Levels For Agricultural Use, John Hondred Jan 2019

Design And Rapid Prototyping Of Printed Graphene Electrochemical Biosensors For Sensitive Monitoring Of Pesticide Levels For Agricultural Use, John Hondred

Graduate Theses and Dissertations

While the use of pesticides (herbicides and insecticides) are critically important to meet the current and future food demands (increases crop yield by up to 40%), their overuse has shown long-term detrimental impacts on the environment from polluting watersheds used for drinking water to eutrophic “dead zones”. Current pesticide soil measurement methods (chromatography) are costly, require trained technicians, and take days to analyze; thus, farmers are taking an “over-application approach” which is pollution the environment and waterways. A disposable pesticide soil sensor would provide farmers the opportunity of precisely regulating the application of pesticides in an independent and economical fashion ...


Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng Jan 2019

Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng

Graduate Theses and Dissertations

Metal particles like aluminum and boron are of great interest as additives to energetic materials due to their high gravimetric and volumetric heat of combustion. However, the ignition temperatures of metals are quite high and their burning rates which depend upon the surface area of the burning metal agglomerates are quite slow. The naturally formed oxide layer on the surface of metal particles can further inhibit their ignition and combustion by limiting fuel/oxidizer transport. The boron oxide layer on boron particles is of particular interest due to the strong diffusion barrier formed by its presence. However, the ignition temperature ...


Modeling Grain Storage Outflow Contamination Levels, Based Upon Input Time Series, Anne E. Dohmen Jan 2019

Modeling Grain Storage Outflow Contamination Levels, Based Upon Input Time Series, Anne E. Dohmen

Graduate Theses and Dissertations

The main objective of this thesis was to use a modeling approach to simulate the concentration of grain contamination in an existing corn processing system. The majority of the plant input is GMO corn, which is processed into multiple end products. In addition to GMO corn, each year, the plant processes six 11-day runs of non-GMO corn. During these non-GMO runs, the overall GMO contamination of the products produced is required to be less than 0.9% per the 3rd party labeling organization Non-GMO Project standards. Each run takes in approximately 1,400 lots (1000 bu/lot), with a sub-sample ...


Intelligent Team Tutoring: An Analysis Of Communication, Cognition, Cooperation, And Coordination, Kaitlyn M. Ouverson Jan 2019

Intelligent Team Tutoring: An Analysis Of Communication, Cognition, Cooperation, And Coordination, Kaitlyn M. Ouverson

Graduate Theses and Dissertations

This thesis describes the evaluation of an Intelligent Team Tutoring System (ITTS) designed to teach team and task skills to improve team and individual performance. Previous work has revealed how team communication, shared situational awareness and mental models, and collective efficacy contribute to the success of a team and how these phenomena are molded by the team members’ interactions. However, less research has explored the impacts of an ITTS on these dimensions of teamwork. The present study was conducted on 37 teams of three who took on one of two roles – spotter (two people) or sniper – in a military-style task ...


Investigation Of The Photophysical Properties Of Energy-Relevant Inorganic Nanocrystals, Brett Boote Jan 2019

Investigation Of The Photophysical Properties Of Energy-Relevant Inorganic Nanocrystals, Brett Boote

Graduate Theses and Dissertations

Environmental concerns over use of fossil fuels to generate power and the finite supply of these resources have driven major efforts for alternative energies. At the same time, the development of nanotechnology has blossomed to propose strategies and materials for renewable and less energy-intensive end-user devices, such as solar cells and LED lighting. Two examples of promising candidates for energy applications are germanium-based nanocrystals and lead halide perovskite nanocrystals.

Germanium-based materials have limited absorption efficiency due to their indirect band gap. To address this, germanium-tin alloy nanocrystals were synthesized to promote direct band gap character. A full characterization demonstrated tin ...


Development Of Performance Models To Determine Effectiveness Of Flexible Pavement Preservation Using A Pavement Management System, Benjamin Claypool Jan 2019

Development Of Performance Models To Determine Effectiveness Of Flexible Pavement Preservation Using A Pavement Management System, Benjamin Claypool

Graduate Theses and Dissertations

More, now than ever, importance on saving materials, time, and money is at the forefront of infrastructure maintenance. Large strides have been made to achieve these goals through the use of pavement preservation. A properly applied preservation method will extend the service life of the pavement, use less materials than a typical overlay or reconstruction, and result in lower construction costs. The presented research evaluates a variety of analytical methods used to model the performance of four different flexible pavement preservation methods, including microsurfacing, slurry sealing, patching, and crack/joint sealing.

Best-fit curves were applied to performance data from the ...


Calcium Passivation And Properties Of Al/Ca Composite Conductors, Charles Czahor Jan 2019

Calcium Passivation And Properties Of Al/Ca Composite Conductors, Charles Czahor

Graduate Theses and Dissertations

Light, strong, high-conductivity materials are desirable for overhead power transmission and distribution conductors. An aluminum/calcium composite with nanofilamentary reinforcement was produced by powder metallurgy and deformation processing to fine wires. Upon achieving the desired dimension, the wires were heat treated to convert the calcium to Al2Ca intermetallic reinforcement filaments. Extended heat treatments were used to evaluate the upper operating temperature of the material. The processing steps, microstructure, conductivity, and tensile strength of Al/Ca composites were evaluated. The measured properties indicate that the number of support towers required for a HVDC transmission line can be reduced by more than ...


Insights Into Performance Stability Of Lead-Free Piezoelectric Ceramics, Zhongming Fan Jan 2019

Insights Into Performance Stability Of Lead-Free Piezoelectric Ceramics, Zhongming Fan

Graduate Theses and Dissertations

Developing materials with superior functional properties is the primary goal of materials engineering. Nonetheless, the stability of performance during practical service should be of equal importance. This is, with no doubt, also true for piezoelectric materials.

The working conditions of piezoelectric materials can lead to either gradual or abrupt degradation in their functional properties. First, fatigue. In analogy to structural materials under cyclic stresses, the piezoelectric properties deteriorate during the electric field cycling. Second, aging. While the service is paused and the piezoelectric material is sitting idle, the piezoelectric properties will decay over time. Third, thermal depolarization. Electronic devices are ...


Process Intensification Of Biomass Fast Pyrolysis Via Autothermal Operation, Joseph Patrick Polin Jan 2019

Process Intensification Of Biomass Fast Pyrolysis Via Autothermal Operation, Joseph Patrick Polin

Graduate Theses and Dissertations

Heat transfer is the bottleneck to fast pyrolysis of biomass. Although the enthalpy for pyrolysis of biomass is relatively small, operation at temperatures around 500°C constrains heat carrier selection to inert gases and granular media that can sustain only modest thermal fluxes in practical pyrolysis systems. With heat transfer controlling the rate of pyrolysis, reactor capacity only scales as the square of reactor diameter and does not benefit from economies of scale in building larger reactors. We have eliminated this heat transfer bottleneck by replacing it with partial oxidation of pyrolysis products to provide the enthalpy for pyrolysis in ...


Towards Energy-Efficient Hardware Acceleration Of Memory-Intensive Event-Driven Kernels On A Synchronous Neuromorphic Substrate, Saunak Saha Jan 2019

Towards Energy-Efficient Hardware Acceleration Of Memory-Intensive Event-Driven Kernels On A Synchronous Neuromorphic Substrate, Saunak Saha

Graduate Theses and Dissertations

Spiking neural networks are increasingly becoming popular as low-power alternatives to deep learning architectures. To make edge processing possible in resource-constrained embedded devices, there is a requirement for reconfigurable neuromorphic accelerators that can cater to various topologies and neural dynamics typical to these networks. Subsequently, they also must consolidate energy consumption in emulating these dynamics. Since spike processing is essentially memory-intensive in nature, a significant proportion of the system's power consumption can be reduced by eliminating redundant memory traffic to off-chip storage that holds the large synaptic data for the network. In this work, I will present CyNAPSE, a ...


Evaluating The Effect Of Displaying Team Vs. Individual Metrics On Team Performance, Jamiahus Walton Jan 2019

Evaluating The Effect Of Displaying Team Vs. Individual Metrics On Team Performance, Jamiahus Walton

Graduate Theses and Dissertations

Teams have the potential to display high performance or low performance, depending on how well team members interact with one another. Training is commonly used to maintain or enhance the performance of various team types (e.g., sport or work teams). Intelligent Tutoring Systems (ITSs) have been used for years in multiple domains to tutor individuals. However, challenges arise when attempting to develop an Intelligent Team Tutoring System (ITTS). This current work focuses on the challenge of delivering effective feedback to teams via an ITTS designed to improve team performance. This research specifically focuses on how the assessment basis of ...


Big Data Driven Assessment Of Probe-Sourced Data, Vesal Ahsani Jan 2019

Big Data Driven Assessment Of Probe-Sourced Data, Vesal Ahsani

Graduate Theses and Dissertations

Presently, there is an expanding interest among transportation agencies and state Departments of Transportation to consider augmenting traffic data collection with probe-based services, such as INRIX. The objective is to decrease the cost of deploying and maintaining sensors and increase the coverage under constrained budgets. This dissertation documents a study evaluating the opportunities and challenges of using INRIX data in Midwest. The objective of this study is threefold: (1) quantitative analysis of probe data characteristics: coverage, speed bias, and congestion detection precision (2) improving probe based congestion performance metrics accuracy by using change point detection, and (3) assessing the impact ...


Controlled Cavitation Design And Investigation Of Its Effect In Traumatic-Brain Injuries, Alex Wrede Jan 2019

Controlled Cavitation Design And Investigation Of Its Effect In Traumatic-Brain Injuries, Alex Wrede

Graduate Theses and Dissertations

Traumatic brain injuries (TBIs) are a highly complex injury that is heavily studied in modern research. An aspect of TBIs that has been almost entirely overlooked is the existence of cavitation in the brain during a high impact injury. The presence of cavitation in the brain is a recent theory and is feared to cause detrimental damages on brain tissue. The following chapters aim to investigate this phenomena by first engineering an apparats that simulates controlled cavitation for TBI applications. The apparatus that is used in this study involves acoustical techniques to cause microbubbles (MBs) to oscillate and fragment under ...


Solving Arc Routing Problems For Winter Road Maintenance Operations, Luning Zhang Jan 2019

Solving Arc Routing Problems For Winter Road Maintenance Operations, Luning Zhang

Graduate Theses and Dissertations

For winter road maintenance, a fleet of snowplow trucks is operated by government agencies to remove snow and ice on roadways and spread materials for anti-icing, de-icing, or increasing friction. Winter road maintenance is essential for providing safe and efficient service for road users (Usman et al., 2010). It is also costly due to the high cost of equipment, crew, and materials. Optimizing winter road maintenance operations could result in significant cost savings, improved safety and mobility, and reduced environmental and social impacts (Salazar-Aguilar et al., 2012).

The first topic in this study focuses on designing routes for winter maintenance ...


Advanced Manufacturing And Nanotechnology For Non-Noble Metal-Based Oxygen Evolution Electrocatalysts, Bowei Zhang Jan 2019

Advanced Manufacturing And Nanotechnology For Non-Noble Metal-Based Oxygen Evolution Electrocatalysts, Bowei Zhang

Graduate Theses and Dissertations

The oxygen evolution reaction (OER) plays vital roles in electrochemical energy conversion and storage applications, including water-splitting systems, fuel cells, metal-air batteries, and CO2 reduction devices, but the development of highly active and robust OER catalysts based on non-noble metals by simple methods is challenging. In this dissertation, three major strategies are proposed for developing advanced OER electrocatalysts at low cost by simple and versatile methods. In the first work, a bimetallic Ni-Fe-P nanosheet arrays were designed and fabricated as a pre-catalyst to catalyzing super high OER current densities under alkaline and neutral media. To catalyze a 10 mA/cm2 ...


Deep Learning For Monitoring Cyber-Physical Systems, Tryambak Gangopadhyay Jan 2019

Deep Learning For Monitoring Cyber-Physical Systems, Tryambak Gangopadhyay

Graduate Theses and Dissertations

Different cyber-physical systems involving sequential data require accurate frameworks for predicting the state of the system leading to effective monitoring. If the framework is explanatory, the insights provided by the explanations can improve scientific understanding of the system. Detecting the transition to an impending instability is important to initiate effective control in a combustion system. Building robust frameworks is important in this context.

As one of the early applications of characterizing instability in a combustion system using Deep Neural Networks, we train our proposed deep convolutional neural network (CNN) model on sequential image frames extracted from hi-speed flame videos by ...


Use Of Soft Computing And Numerical Analysis In Design, Analysis And Management Of Pavement Systems, Orhan Kaya Jan 2019

Use Of Soft Computing And Numerical Analysis In Design, Analysis And Management Of Pavement Systems, Orhan Kaya

Graduate Theses and Dissertations

There are a number of components of pavement engineering, including pavement management, pavement analysis and design, and pavement materials. Historically, the field of pavement management has been interested in monitoring post-construction condition, timing of preventive maintenance and rehabilitation treatments, and economic analysis of alternatives. On the other hand, the field of pavement analysis and design has dealt with optimizing pavement structure; with optimum structure, a pavement system is expected to survive during its service life for given traffic and climate conditions. The performance of pavement materials has been improved to achieve the long-lasting and lower-maintenance pavement systems. A data-driven comprehensive ...


Applying Computer Vision For Detection Of Diseases In Plants, Xuan Truong Tran Jan 2019

Applying Computer Vision For Detection Of Diseases In Plants, Xuan Truong Tran

Graduate Theses and Dissertations

Early detection and quantification of diseases in food plants are critical to agriculture industry and national food security. However, limitation in technology and cost has limited the success of applying Computer Vision in Plant Science. This research builds on the recent advance of Machine Learning, GPU and smartphones to tackle the problem of fast and low cost diagnosis of plant disease. In particular, we choose soybean as the subject for applying automatic disease detection. The reason is because soybean is an important crop for the state of Iowa and an important source of food for America. The plant is however ...


Physical Characterization, Calibration, And Validation Methodology For Modeling Of Grains Using Discrete Element Method (Dem), Mohammad Mousaviraad Jan 2019

Physical Characterization, Calibration, And Validation Methodology For Modeling Of Grains Using Discrete Element Method (Dem), Mohammad Mousaviraad

Graduate Theses and Dissertations

Discrete element method (DEM) as a numerical technique for modeling granular materials has been developed for predicting the dynamic behavior of bulk particulate systems. Simulation of bulk grain handling in crop harvesting machine using the DEM technique have been challenging owing to the variability of corn conditions (e.g., grain moisture content) and limitation of robust DEM calibration procedures. Although DEM has provided an invaluable qualitative understanding of the particle flow inside or in contact with equipment, quantitatively accurate DEM simulation of particle flow and particle-machine interaction for engineering design and analysis has been generally limited. The objective of this ...


A Top-Down Human-Centered Approach To Exoskeleton Design, Thomas Michael Schnieders Jan 2019

A Top-Down Human-Centered Approach To Exoskeleton Design, Thomas Michael Schnieders

Graduate Theses and Dissertations

This dissertation begins, as all good research does, with a thorough review of the literature. The literature is broken into three primary sections covering the early 1960’s when information on exoskeletons was first published up to 1970, then the formative years of 1970 to 2000 where much of the primary technology was developed, and finally 2000 to present where new advancements in battery density, computer processing, and materials leads to more robust and advanced exoskeleton designs. The literature review determines the areas where there is a dearth of research or places needing further examination and lays the groundwork for ...


Data-Driven Analyses Of Future Electric Personal Mobility, Liang Hu Jan 2019

Data-Driven Analyses Of Future Electric Personal Mobility, Liang Hu

Graduate Theses and Dissertations

Personal mobility is moving towards the era of electrification. Adopting electric vehicles (EV) is widely regarded as an effective solution to energy crisis and air pollution. Many automakers have announced their roadmap to electrification in the next 1-2 decades. At the same time, limited electric range and insufficient charging infrastructure are still obstacles to EV large-scale adoption. However, with the emerging technologies of ride-hailing, connected vehicles, and autonomous vehicles, these obstacles are being solved effectively, and the EV market penetration is expected to increase significantly. Among the many kinds of electric mobility, electric taxis and personal battery electric vehicles (BEV ...


Variable Friction Cladding Connection For Multi-Hazard Mitigation, Yongqiang Gong Jan 2019

Variable Friction Cladding Connection For Multi-Hazard Mitigation, Yongqiang Gong

Graduate Theses and Dissertations

Safety and serviceability design of civil infrastructure, including buildings and energy, lifeline, communication, and transportation systems, is critical in providing and maintaining services and benefits to our communities. In modern society, new constructions tend to be more flexible due to advances in material science and construction technologies. A key challenge in the design of these structures is to meet the motion requirements under operational and extreme loadings. The purpose of a motion-based design (MBD) approach is to ensure that motion requirements are met under the design loads, after which strength requirements are verified and met. A popular method under MBD ...


Comparison Of Urans And Des Models For Dynamic Stall Of Naca 0012 At Low Reynolds Number, Anshul Chandel Jan 2019

Comparison Of Urans And Des Models For Dynamic Stall Of Naca 0012 At Low Reynolds Number, Anshul Chandel

Graduate Theses and Dissertations

Designing wings and rotor blades to mitigate the adverse effects of dynamic stall is of current interest. For example, unmanned air vehicles with vertical take-off and landing capability are particularly susceptible to dynamic stall as they operate entirely in the highly unsteady planetary boundary layer. The intense unsteady loads generated as the vehicle undergoes dynamic stall can lead to catastrophic failure as well as fatigue failure. A passive mechanism to mitigate dynamic stall is a desirable alternative to active control as it is simpler, robust, and economical. Innovative wing and rotor blade designs can be developed using numerical simulations and ...