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Full-Text Articles in Engineering

Compiler-Based Tools To Aid In Data Transfer Optimization And On-Chip Debug Of Heterogeneous Compute Systems, Matthew B. Ashcraft Jul 2020

Compiler-Based Tools To Aid In Data Transfer Optimization And On-Chip Debug Of Heterogeneous Compute Systems, Matthew B. Ashcraft

Theses and Dissertations

First, we present techniques to efficiently schedule data transfers through compiler analyses. Compared to transferring data immediately before and after the kernel executes, our scheduling results in orders of magnitude improvements in execution time, number of data transfers, and number of bytes transferred. Second, we demonstrate techniques to provide on-chip debugging for heterogeneous systems through recording execution on the software in addition to debugging circuitry in the hardware, and provide a temporal correlation between the hardware and software traces through synchronization. This allows us to follow debug data between the hardware and software trace buffers. Due to the added cost …


0.03 V Electrolysis Voltage Driven Hydrazine Assisted Hydrogen Generation On Nico Phosphide Nanowires Supported Nicohydroxide Nanosheets, Mujie Li, Zhongyi Zhang, Hailang Xiong, Linan Wang, Shuxian Zhuang, Morris D. Argyle, Yang Tang, Xiaojin Yang, Yongmei Chen, Pingyu Wan, Maohong Fan Jul 2020

0.03 V Electrolysis Voltage Driven Hydrazine Assisted Hydrogen Generation On Nico Phosphide Nanowires Supported Nicohydroxide Nanosheets, Mujie Li, Zhongyi Zhang, Hailang Xiong, Linan Wang, Shuxian Zhuang, Morris D. Argyle, Yang Tang, Xiaojin Yang, Yongmei Chen, Pingyu Wan, Maohong Fan

Faculty Publications

In order to decrease the electricity consumption of hydrogen generation, hydrazine-assisted water electrolysis is intensively investigated recently. Herein, hierarchical nanostructure of ultrathin NiCo(OH)x nanosheets (NSs) that in-situ grown on the NiCoP nanowires (NWs) was deposited on nickel foam (NF) to construct NiCo(OH)x@NiCoP/NF electrode. NiCoP NWs extend the surface area, spatial utilization of NF and enhance the electron conduction to the outmost NiCo(OH)x NSs. NiCo(OH)x NSs interlace to form regular mesoporous channels, which improve the structural stability and mass transfer rate. Moreover, NiCoP NWs enhance the adsorption of protons and the transfer of electrons, while NiCo(OH) …


Incorporating Stability In Deployable Origami-Based Engineering Applications, David Wayne Andrews Jul 2020

Incorporating Stability In Deployable Origami-Based Engineering Applications, David Wayne Andrews

Theses and Dissertations

For origami-based designs to be functional, they need to be stable. Typically, stability is achieved through the introduction of exterior supports or members. This work focuses on incorporating stability into deployable origami-based engineering applications, including the development of deployable stiffeners or hard stops and generating concepts for stable origami-based systems in specific applications. Two types of deployable stiffeners are developed. Models for transcrease hard stops are presented, which can be directly implemented into origami-patterns to block motion at a specified angle. Thickness Utilizing Deployable Hard Stops (ThUDS), adapted from the transcrease hard stop models, can be implemented into thick materials …


Groundwater Level Mapping Tool: An Open Source Web Application For Assessing Groundwater Sustainability, Steven W. Evans, Norman L. Jones, Gustavious P. Williams, Daniel P. Ames, E. James Nelson Jul 2020

Groundwater Level Mapping Tool: An Open Source Web Application For Assessing Groundwater Sustainability, Steven W. Evans, Norman L. Jones, Gustavious P. Williams, Daniel P. Ames, E. James Nelson

Faculty Publications

Decision makers need an accurate understanding of aquifer storage trends to effectively manage groundwater resources. Groundwater is difficult to monitor and quantify since the data collected from monitoring wells are often available only at irregular and infrequent intervals. We present an open-source web application (app) to visualize groundwater data over time and automatically calculate changes in aquifer storage volume to help managers assess aquifer sustainability. This app uses a novel multi-linear regression (MLR) algorithm to impute missing data for infrequently sampled wells, using correlated data from other wells in the same aquifer. The app uses this MLR-imputed data to spatially …


Rotor-On-Rotor Aeroacoustic Interactions Of Multirotor In Hover, Eduardo Alvarez, Austin Schenk, Tyler Critchfield, Andrew Ning Jul 2020

Rotor-On-Rotor Aeroacoustic Interactions Of Multirotor In Hover, Eduardo Alvarez, Austin Schenk, Tyler Critchfield, Andrew Ning

Faculty Publications

Multirotor configurations introduce complicated aerodynamic and aeroacoustic interactions that must be considered during aircraft design. In this paper we explore two numerical methods to model the acoustic noise caused by aerodynamic rotor-on-rotor interactions of rotors in hover. The first method uses a conventional mesh-based unsteady Reynolds-average Navier-Stokes (URANS) solver, while the second consists of a meshless Lagrangian solver based on the viscous vortex particle method (VPM). Both methods are coupled with an aeroacoustics solver for tonal and broadband noise predictions. Noise predictions are validated for single and multi-rotor configurations, obtaining with the VPM a similar accuracy than URANS while being …


Tracking Joint Angles During Whole-Arm Movements Using Electromagnetic Sensors, Ryan Clark, Taylor Dickinson, Johnfredy Loaiza, Daniel W. Geiger, Steven Knight Charles Jul 2020

Tracking Joint Angles During Whole-Arm Movements Using Electromagnetic Sensors, Ryan Clark, Taylor Dickinson, Johnfredy Loaiza, Daniel W. Geiger, Steven Knight Charles

Faculty Publications

Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in-vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors …


Exploiting Earth Observation Data To Impute Groundwater Level Measurements With An Extreme Learning Machine, Steven Evans, Gustavious P. Williams, Norman L. Jones, Daniel P. Ames, E. James Nelson Jun 2020

Exploiting Earth Observation Data To Impute Groundwater Level Measurements With An Extreme Learning Machine, Steven Evans, Gustavious P. Williams, Norman L. Jones, Daniel P. Ames, E. James Nelson

Faculty Publications

Groundwater resources are expensive to develop and use; they are difficult to monitor and data collected from monitoring wells are often sporadic, often only available at irregular, infrequent, or brief intervals. Groundwater managers require an accurate understanding of historic groundwater storage trends to effectively manage groundwater resources, however, most if not all well records contain periods of missing data. To understand long-term trends, these missing data need to be imputed before trend analysis. We present a method to impute missing data at single wells, by exploiting data generated from Earth observations that are available globally. We use two soil moisture …


Evaluating And Improving The Seu Reliability Of Artificial Neural Networks Implemented In Sram-Based Fpgas With Tmr, Brittany Michelle Wilson Jun 2020

Evaluating And Improving The Seu Reliability Of Artificial Neural Networks Implemented In Sram-Based Fpgas With Tmr, Brittany Michelle Wilson

Theses and Dissertations

Artificial neural networks (ANNs) are used in many types of computing applications. Traditionally, ANNs have been implemented in software, executing on CPUs and even GPUs, which capitalize on the parallelizable nature of ANNs. More recently, FPGAs have become a target platform for ANN implementations due to their relatively low cost, low power, and flexibility. Some safety-critical applications could benefit from ANNs, but these applications require a certain level of reliability. SRAM-based FPGAs are sensitive to single-event upsets (SEUs), which can lead to faults and errors in execution. However there are techniques that can mask such SEUs and thereby improve the …


Dynamic Reconfigurable Real-Time Video Processing Pipelines On Sram-Based Fpgas, Andrew Elbert Wilson Jun 2020

Dynamic Reconfigurable Real-Time Video Processing Pipelines On Sram-Based Fpgas, Andrew Elbert Wilson

Theses and Dissertations

For applications such as live video processing, there is a high demand for high performance and low latency solutions. The configurable logic in FPGAs allows for custom hardware to be tailored to a specific video application. These FPGA designs require technical expertise and lengthy implementation times by vendor tools for each unique solution. This thesis presents a dynamically configurable topology as an FPGA overlay to deploy custom hardware processing pipelines during run-time by utilizing dynamic partial reconfiguration. Within the FPGA overlay, a configurable topology with a routable switch allows video streams to be copied and mixed to create complex data …


Development And Evaluation Of Dimensionally Adaptive Techniques For Improving Computational Efficiency Of Radiative Heat Transfer Calculations In Cylindrical Combustors, Todd Andrew Williams Jun 2020

Development And Evaluation Of Dimensionally Adaptive Techniques For Improving Computational Efficiency Of Radiative Heat Transfer Calculations In Cylindrical Combustors, Todd Andrew Williams

Theses and Dissertations

Computational time to model radiative heat transfer in a cylindrical Pressurized Oxy-Coal (POC) combustor was reduced by incorporating the multi-dimensional characteristics of the combustion field. The Discrete Transfer Method (DTM) and the Discrete Ordinates Method (DOM) were modified to work with a computational mesh that transitions from 3D cells to axisymmetric and then 1D cells, also known as a dimensionally adaptive mesh. For the DTM, three methods were developed for selecting so-called transdimensional rays, the Single Unweighted Ray (SUR) technique, the Multiple Unweighted Ray (MUR) technique, and the Single Weighted Ray (SWR) technique. For the DOM, averaging methods for handling …


Thermal Conductivity And Diffusivity Measurement Assessment For Nuclear Materials Raman Thermometry For Uranium Dioxide And Needle Probe For Molten Salts, Peter Ward Hartvigsen Jun 2020

Thermal Conductivity And Diffusivity Measurement Assessment For Nuclear Materials Raman Thermometry For Uranium Dioxide And Needle Probe For Molten Salts, Peter Ward Hartvigsen

Theses and Dissertations

In the near future, Gen II, III, and IV nuclear reactors will be in operation. UO2 is a common fuel for reactors in each of these generations and molten salts are used as coolant/fuel in Gen IV molten salt reactors. This thesis investigates potential ways to measure thermal conductivity for these materials: Raman thermometry for UO2 and a needle probe for molten salts. Four Raman thermometry techniques are investigated in this thesis: The Two Laser Raman (TLR), Time Differential Domain Raman (TDDR), Frequency Resolved Raman (FRR), and Frequency Domain Raman (FDR). The TLR is a steady state method used with …


Increasing The Manufacturing Readiness Of Refill Friction Stir Spot Welding, Brigham Ammon Larsen Jun 2020

Increasing The Manufacturing Readiness Of Refill Friction Stir Spot Welding, Brigham Ammon Larsen

Theses and Dissertations

Refill friction stir spot welding (RFSSW) is an emerging technology, capable of joining thin sheets of aluminum alloys. The present thesis comprises two studies which were conducted to address two challenges faced by RFSSW: the long cycle time traditionally associated with welding and the poor life of existing RFFSW tools. In the first study, welds were made in AA5052-H36, at various cycle times and with various process parameters. It was shown that RPM, cycle time, and material thickness, all have an effect on the machine response. Decreasing RPM or weld duration leads to increased force and torque response during welding. …


Lcm Permeability Characterization Over Mold Curvature, Benjamin Grant Betteridge Jun 2020

Lcm Permeability Characterization Over Mold Curvature, Benjamin Grant Betteridge

Theses and Dissertations

Composite flow simulation tools for LCM processing can be expensive and time-consuming but necessary to design a mold system with proper placement of resin inlets and vacuum outlets. Composites manufacturing engineers would benefit from data regarding the impact of mold curvature radius on resin flow. This could help determine whether or not a particular part and mold would require expensive simulation software designed to handle complex flow paths through curved fabric architectures exhibiting variable permeability over the curvature, or if simple flow modeling would provide accurate enough simulations for sound tooling setup decision making. Four molds, with double curvature having …


Observing The Impact Of An Engineering-Based Unit Of Instruction On 6th Grade Students' Attitudes Towards Engineering As Theyengage In Building Electric Bikes, Gregg Allred Olsen Jun 2020

Observing The Impact Of An Engineering-Based Unit Of Instruction On 6th Grade Students' Attitudes Towards Engineering As Theyengage In Building Electric Bikes, Gregg Allred Olsen

Theses and Dissertations

In the past few decades, science, technology, engineering, and math (STEM) education has become a driving force for innovators throughout the world (Atkinson & Mayo, 2010; Bybee, 2010). STEM education has also become an economic factor in developing countries (Kennedy & Odell, 2014). Currently, many countries are struggling with how to effectively promote STEM education. The United States (U.S.) provides an interesting case study. Despite being one of the global economic leaders, it is behind in STEM education compared to other nations (Atkinson & Mayo, 2010; Dugger, 2010). STEM education helps to build world leaders including marketable and knowledgeable employees …


Creating Library Learning Spaces That Support Twenty-First Century Pedagogy And Student Learning, Deborah Lynn Christoffersen Jun 2020

Creating Library Learning Spaces That Support Twenty-First Century Pedagogy And Student Learning, Deborah Lynn Christoffersen

Theses and Dissertations

University libraries struggle to keep up with rapidly changing technology and the associated change in teaching strategy. Most administrators and librarians are often not trained to assess space needs and struggle to reassign library spaces for non-traditional library use. As such, they often embark on expensive and time-consuming feasibility studies, using (typically) hard-earned monies to complete the research or to pilot a new space. What academic research library administrators and staff lack is an analysis tool for discovering and planning needed renovations and improvements in aging library facilities. The purpose of this research project was to determine how students use …


An Agent-Based Decision Support Framework For Suas Deployment In Small Infantry Units, Carsten Douglas Christensen Jun 2020

An Agent-Based Decision Support Framework For Suas Deployment In Small Infantry Units, Carsten Douglas Christensen

Theses and Dissertations

Small unmanned aircraft systems (sUAS) will become a disruptive force on the modern battlefield. In recent years, sUAS size and cost have decreased while their capability has increased. They have forced a reconsideration of the air superiority paradigm held since the First World War. Perhaps their most attractive, and worrisome, feature is the huge range of combat roles that they might fulfill. The presence of sUAS on future battlefields is certain, but the role they will play and their impact on those battlefields are not. This work presents a decision support framework for sUAS deployment in small infantry units. The …


Quantifying The Conditioning Period For Geogrid-Reinforced Aggregate Base Materials Through Cyclic Loading, Chad Derrick Vickery Jun 2020

Quantifying The Conditioning Period For Geogrid-Reinforced Aggregate Base Materials Through Cyclic Loading, Chad Derrick Vickery

Theses and Dissertations

Geogrid reinforcement can improve the performance of pavements by stiffening the aggregate base material and decreasing pavement deformations. Understanding the effects of cyclic loading on the modulus of geogrid-reinforced base materials would help engineers better anticipate actual increases in the modulus of aggregate base materials under given traffic loads. The objective of this laboratory research was to investigate the effects of cyclic loading on the resilient modulus, the modulus to peak axial stress, the elastic modulus, and the modulus at 2 percent strain of geogrid-reinforced aggregate base materials. The scope of the research included two aggregate base materials (Wells Draw …


Impacts Of Changing The Transit Signal Priority Requesting Threshold On Bus Performance And General Traffic: A Sensitivity Analysis, Michael Harmon Sheffield Jun 2020

Impacts Of Changing The Transit Signal Priority Requesting Threshold On Bus Performance And General Traffic: A Sensitivity Analysis, Michael Harmon Sheffield

Theses and Dissertations

A sensitivity analysis was performed on the transit signal priority (TSP) requesting threshold to evaluate its impact on bus performance and general traffic. Two distinct bus routes were evaluated to determine the optimal requesting threshold that would balance the positive impacts on bus performance with the negative impacts on general traffic. Route 217, a conventional bus route, and the Utah Valley Express (UVX), a bus rapid transit line, utilize a dedicated short-range communication (DSRC)-based TSP system as part of their normal, day-to-day operations. Using field-generated data exclusively, bus performance and general traffic were evaluated over a 7-month period from February …


A Systems-Level Approach To The Design, Evaluation, And Optimization Of Electrified Transportation Networks Using Agent-Based Modeling, Landon Clark Willey Jun 2020

A Systems-Level Approach To The Design, Evaluation, And Optimization Of Electrified Transportation Networks Using Agent-Based Modeling, Landon Clark Willey

Theses and Dissertations

Rising concerns related to the effects of traffic congestion have led to the search for alternative transportation solutions. Advances in battery technology have resulted in an increase of electric vehicles (EVs), which serve to reduce the impact of many of the negative consequences of congestion, including pollution and the cost of wasted fuel. Furthermore, the energy-efficiency and quiet operation of electric motors have made feasible concepts such as Urban Air Mobility (UAM), in which electric aircraft transport passengers in dense urban areas prone to severe traffic slowdowns. Electrified transportation may be the solution needed to combat urban gridlock, but many …


Performance Of A Full-Scale Rammed Aggregate Pier Group In Silty Sand Based On Blast-Induced Liquefaction Testing In Emilia-Romagna, Italy, Paul Joseph Walsh Andersen Jun 2020

Performance Of A Full-Scale Rammed Aggregate Pier Group In Silty Sand Based On Blast-Induced Liquefaction Testing In Emilia-Romagna, Italy, Paul Joseph Walsh Andersen

Theses and Dissertations

To investigate the liquefaction mitigation capability of Rammed Aggregate Piers® (RAP) in silty sand, blast liquefaction testing was performed at a soil profile treated with a full-scale RAP group relative to an untreated soil profile. The RAP group consisted of 16 piers in a 4x4 arrangement at 2 m center-to-center spacing extending to a depth of 9.5 m. Blasting around the untreated area induced liquefaction (ru ≈1.0) from 3 m to 11 m depth, producing several large sand boils, and causing settlement of 10 cm. In contrast, installation of the RAP group reduced excess pore water pressure (ru ≈0.75), eliminated …


Analysis Of Performance Measures Of Traffic Incident Management In Utah, Mitchell Gregory Hadfield Jun 2020

Analysis Of Performance Measures Of Traffic Incident Management In Utah, Mitchell Gregory Hadfield

Theses and Dissertations

In 2009 the Federal Highway Administration published a report regarding a Focus States Initiative that had been conducted with 11 states to discuss the development of national Traffic Incident Management (TIM) standards. Performance measures were defined, and a national TIM dashboard created, but very little data has been added to the dashboard since. In this research study, performance measures of the Utah Department of Transportation (UDOT) TIM program were analyzed. Data availability was first assessed to determine whether these performance measures could be calculated. It was determined that crash response data available from the Utah Highway Patrol (UHP) could be …


Evaluating The Impacts Of Hurricane Maria On The Residential Construction Industry In Puerto Rico And The Effectiveness Of Reconstruction Efforts, M. Bradley Wells Jun 2020

Evaluating The Impacts Of Hurricane Maria On The Residential Construction Industry In Puerto Rico And The Effectiveness Of Reconstruction Efforts, M. Bradley Wells

Theses and Dissertations

In September of 2017, Hurricane Irma and Hurricane Maria, both category 5 hurricanes, swept across the Caribbean, including the U.S. Territory island of Puerto Rico. These two storms, particularly Hurricane Maria, caused catastrophic damages from high winds and flooding to the island paradise. This research investigates the direct effects that Hurricane Maria had on the residential construction industry within Puerto Rico and evaluates how to better prioritize and manage these types of efforts in the future. This research was initiated to identify challenges and opportunities that have been encountered within the Puerto Rican construction industry during the first year of …


Designing Developable Mechanisms On Conical And Cylindrical Developable Surfaces, Lance Parker Hyatt Jun 2020

Designing Developable Mechanisms On Conical And Cylindrical Developable Surfaces, Lance Parker Hyatt

Theses and Dissertations

The research results presented in this thesis provide tools and methods to aid in the design of developable mechanisms. This work will help engineers design compact mechanisms onto developable surfaces, making it possible for them to be used in future applications. The thesis introduces terminology and definitions to describe conical developable mechanisms. Models are developed to describe mechanism motion with respect to the apex of the conical surface, and connections are made to cylindrical developable mechanisms using projected angles. The Loop Sum Method is presented as an approach to determine the geometry of the cone to which a given spherical …


Computational Investigation Of The Effects Of Rotor-On-Rotor Interactions On Thrust And Noise, Austin R. Schenk Jun 2020

Computational Investigation Of The Effects Of Rotor-On-Rotor Interactions On Thrust And Noise, Austin R. Schenk

Theses and Dissertations

Recent advancements in electric propulsion systems have made electric vertical takeoff and landing aircraft a reality, and one that is seen as a partial solution to the growing issue of urban traffic congestion. Designing an aircraft with multiple smaller motors and rotors spread across the wings–referred to as distributed electric propulsion (DEP)–has shown great potential in help- ing improve electric aircraft performance by offering increased propulsive efficiency, augmented lift, and structural load distribution. For these reasons, DEP is one configuration that is currently being implemented into multiple prototype designs (e.g. NASA’s Maxwell X-57, Airbus Vahana, Opener BlackFly, and Joby S2). …


Optimized 3d Reconstruction For Infrastructure Inspection With Automated Structure From Motion And Machine Learning Methods, Samuel Arce Munoz Jun 2020

Optimized 3d Reconstruction For Infrastructure Inspection With Automated Structure From Motion And Machine Learning Methods, Samuel Arce Munoz

Theses and Dissertations

Infrastructure monitoring is being transformed by the advancements on remote sensing, unmanned vehicles and information technology. The wide interaction among these fields and the availability of reliable commercial technology are helping pioneer intelligent inspection methods based on digital 3D models. Commercially available Unmanned Aerial Vehicles (UAVs) have been used to create 3D photogrammetric models of industrial equipment. However, the level of automation of these missions remains low. Limited flight time, wireless transfer of large files and the lack of algorithms to guide a UAV through unknown environments are some of the factors that constraint fully automated UAV inspections. This work …


Development Of A 3d Computational Vocal Fold Model Optimization Tool, Austin C. Vaterlaus Jun 2020

Development Of A 3d Computational Vocal Fold Model Optimization Tool, Austin C. Vaterlaus

Theses and Dissertations

One of the primary objectives of voice research is to better understand the biomechanics of voice production and how changes in properties of the vocal folds (VFs) affect voice ability and quality. Synthetic VF models provide a way to observe how changes in geometry and material property affect voice biomechanics. This thesis seeks to evaluate an approach of using a genetic algorithm to design synthetic VF models in three ways: first, through the development of a computationally cost-effective 3D vocal fold model; second, by creating and optimizing a variation of this model; and third, by validating the approach. To reduce …


Identifying High-Potential Work Areas In Engineering For Global Development: Linking Industry Sectors To The Human Development Index, Daniel Oliver Smith Jun 2020

Identifying High-Potential Work Areas In Engineering For Global Development: Linking Industry Sectors To The Human Development Index, Daniel Oliver Smith

Theses and Dissertations

Those working in Engineering for Global Development seek to improve the conditions in developing countries. A common metric for understanding the development state of a given country is the Human Development Index (HDI), which focuses on three dimensions: health, education, and income. An engineer’s expertise does not always align with any of those dimensions directly, while they still hope to perform impactful work for human development. To discover other areas of expertise that are highly associated with the HDI, correlations and variable selection were performed between all World Development Indicators and the HDI. The resultant associations are presented according to …


Byu Diesel Engine Lab Setup And Parasitic Losses Of The Water Pump And Vacuum Pump On A Cummins 2.8l Engine, Eric Ashton Jessup Jun 2020

Byu Diesel Engine Lab Setup And Parasitic Losses Of The Water Pump And Vacuum Pump On A Cummins 2.8l Engine, Eric Ashton Jessup

Theses and Dissertations

The need to minimize carbon dioxide (CO2) emissions is becoming increasingly important with the total number of vehicles throughout the world exceeding one billion. Carbon dioxide emissions can be reduced by improving vehicle fuel efficiency. While electric transportation is gaining popularity, most passenger vehicles are still powered by gasoline or diesel engines. The main objective of this work was to provide opportunities for studying and improving the fuel efficiency of internal combustion engines (ICE). This was achieved by 1) Designing, building and testing auxiliary systems necessary to run a Cummins 2.8 L engine in a an engine test cell; 2) …


Understanding The Relationships Between Ion Transport, Electrode Heterogeneity, And Li-Ion Cell Degradation Through Modeling And Experiment, Fezzeh Pouraghajansarhamami Jun 2020

Understanding The Relationships Between Ion Transport, Electrode Heterogeneity, And Li-Ion Cell Degradation Through Modeling And Experiment, Fezzeh Pouraghajansarhamami

Theses and Dissertations

Electrode microstructure directly affects ion and electron transport and, in turn, has a strong correlation to battery performance. Understanding the separate yet complementary effects of ionic and electronic transport in cell behavior is a challenge. This work provides through a combination of experiments and modeling a better understanding of the relationship between three aspects of the cell: ion transport within the electrode, electrode uniformity, and cell degradation. The first part of this work compares two experimental methods that determine ion transport in terms of tortuosity, a dimensionless geometric factor. The polarization-interrupt and blocking-electrolyte methods measure effective diffusivity and conductivity, respectively. …


Characterization Of Slow Pyrolysis Behavior Of Live And Dead Vegetation, Elham Amini Jun 2020

Characterization Of Slow Pyrolysis Behavior Of Live And Dead Vegetation, Elham Amini

Theses and Dissertations

Prescribed (i.e., controlled) burning is a common practice used in many vegetation types in the world to accomplish a wide range of land management objectives including wildfire risk reduction, wildlife habitat improvement, forest regeneration, and land clearing. To properly apply controlled fire and reduce unwanted fire behavior, an improved understanding of fundamental processes related to combustion of live and dead vegetation is needed. Since the combustion process starts with pyrolysis, there is a need for more data and better models of pyrolysis of live and dead fuels. In this study, slow pyrolysis experiments were carried out in a pyrolyzer apparatus …