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Swimming Upstream: Pathways Of New Engineering Faculty At Non-Rl Institutions, Natascha Trellinger Buswell

Open Access Dissertations

The landscape of engineering academia is varied, yet many graduate students are socialized to aspire to a tenure-track faculty position at a research-intensive institution, and are told that teaching is a necessary activity in order to focus on research. However, some graduate students seek out a PhD so that they can primarily teach at the college level. There exists a misalignment for some graduate students between the way graduate programs in engineering prepare their graduates for academic positions and the way graduates desire to be prepared. In this dissertation, I examined the experiences of twelve assistant professors in engineering who …

Algorithms For Efficient Fail Data Collection For Defect Diagnosis, Shraddha Bodhe

Open Access Dissertations

A tester collects failure information for faulty circuits in order to perform defect diagnosis and derive information about the defects that is important for yield improvement. The increase in the complexity of the semiconductor manufacturing process and the higher number of defects due to scaling have caused an increase in the volume of fail data generated. However, with limited tester memory, fail data collection may terminate without acquiring data that is important for diagnosis. Additionally, a large amount of tester time is spent in data collection, increasing the overall test cost. This thesis presents several algorithms for efficient fail data …

Investigation Of Noise And Vibration In Tires Through Analytical Modeling, Tests And Simulations, Rui Cao

Open Access Dissertations

Tire noise and vibration is an interesting topic, with more and more people paying attention to this issue. Tire noise can both propagate into the vehicle interior and radiate directly toward the immediate environment. Tire noise is not only related to vehicle passengers’ comfort but also affects the residential or working area near highways, especially in high population density regions. The emerging electric vehicles also emphasize tires’ role in vehicle Noise Vibration and Harshness (NVH) since power-train noises are significantly reduced. The study in this research focuses on the noise and vibration of tires from the low to high frequency …

Variability Of Persistent Temporal Correlation In Climate Data, Matthew C. Bowers

Open Access Dissertations

This dissertation examines manifestations of persistent memory in climate data. Persistence is characterized by a slow power-law decay in the autocorrelations of a time series. Its existence implies that the influence of past values in a time series extend into the distant future. It has numerous theoretical implications, notably that it changes the asymptotic decay in the variance of sample means, which can substantially impact the uncertainty in climate mean states. Its intensity can vary over space, time, and other dimensions, e.g. tree species. Variation in its intensity can be used for practical applications such as discriminating between steady and …

Effects Of Calcium Hydroxide Treated Corn Stover Inclusion As A Partial Forage Replacement In Diets For Lactating Dairy Cows, Brittany Casperson

Open Access Dissertations

There is a large quantity of harvestable corn stover available in the United States. Due to the high maturity at harvest and subsequent low digestibility, the use of corn stover as a livestock feedstuff is limited. Several treatment and processing strategies have been explored in order to increase yield of fermentable sugars and lessen the limitation of corn stover as a feedstuff. Alkaline pretreatment has been applied to enhance the digestibility of low quality feeds, improve the feeding value, and permit use in livestock rations. The central hypothesis of this dissertation is that calcium hydroxide treatment would improve the feeding …

Improving The Policy Specification For Practical Access Control Systems, Haining Chen

Open Access Dissertations

Access control systems play a crucial role in protecting the security of information systems by ensuring that only authorized users are granted access to sensitive resources, and the protection is only as good as the access control policies. For enabling a security administrator to express her desired policy conveniently, it is paramount that a policy specification is expressive, comprehensible, and free of inconsistencies. In this dissertation, we study the policy specifications for three practical access control systems (i.e., obligation systems, firewalls, and Security-Enhanced Linux in Android) and improve their expressiveness, comprehensibility, and consistency. First, we improve the expressiveness of obligation …

Design And Synthesis Of Molybdenum-Dioxo Complexes And The Development Of Novel Methodologies, Kelsey Cantwell

Open Access Dissertations

Molybdenum-centered enzymes occur naturally throughout a variety of organisms. These enzymes have shown interesting reactivities, including oxygen atom transfer reactions. As such, there has been a great deal of interest in creating synthetic analogs of these complexes to further probe the reactive properties of molybdenum catalysts. This work focuses on designing and synthesizing molybdenum complexes for oxygen atom transfer reactions. The first chapter will discuss the design, synthesis, and characterization of three molybdenum dioxo complexes used in sulfoxidation reactions. It will also discuss the development of this reaction methodology, as well as cover substrate scope and application to total synthesis …

Border Relations: A Bioarchaeological Lnvestigation Of The Xiongnu Polity, Jeremy J. Beach

Open Access Dissertations

The Xiongnu were the first mobile pastoralist steppe polity to rise up from the Mongolian Steppe. Previous scholarship attributed the emergence of the Xiongnu to their peripheral location and interactions with sedentary China. It was argued that a polity the size of the Xiongnu could not be sustained on a pastoral economy, therefore they turned their attention to interactions with China to fuel their economic and political growth outside of the steppe. This line of thought has come to be known as Dependency Theory and food was at the center of this dependency argument. The expansion of a pastoral economy …

Developing And Measuring Effectiveness Of A New Evidence-Based Grain Storage And Handling Safety Curriculum Targeting Young And Beginning Workers, Yuan-Hsin Cheng

Open Access Dissertations

Research was conducted on the development, testing, and implementation of an original, evidence-based curriculum (Against the Grain) designed to reduce the frequency and severity of the most frequent types of injuries and fatalities involving young and beginning workers, ages 14-20, at grain storage and handling operations. This population has historically accounted for approximately 24% of documented entrapments, engulfments, asphyxiations, entanglements, falls, and electrocutions associated with grain handling and storage. This includes incidents during both workrelated and non-work or recreational activities. Curriculum contents were based upon data summarized from Purdue’s Agricultural Confined Spaces Incident Database (PACSID), review of relevant injury prevention …

Optothermal Energy Conversion And Transport In Plasmonic Structures, Chen Chen

Open Access Dissertations

Plasmonic structures can efficiently interact with electromagnetic waves at their interfaces, leading to strong light confinement and field enhancement, which has been crucial for many nanotechnology applications in manufacturing, lithography, data storage, biosensing, spectroscopy, molecular trapping and other molecular level studies. Due to the intrinsic losses of metallic structures, the strong light-matter interaction also generates significant energy dissipation, making the thermal management of the devices very challenging. The purpose of this dissertation is to study the optothermal energy conversion and transport in plasmonic structures, especially in structures at the nanoscale. We first investigate the general optothermal responses of plasmonic structures …

Multi-Hazard Resilience Of Steel Mrf Buildings, Rachel A. Chicchi

Open Access Dissertations

Multi-hazard analyses can be used to create more sustainable and resilient structural designs by considering cascading hazards and the overall system performance of structures exposed to multiple hazard types. This dissertation develops a methodology to assess building resilience for seismic, wind, fire, and post-earthquake fire scenarios. Special emphasis is placed on understanding the interdependencies and relationships between earthquake and fire damage in the assessment of structures for post-earthquake fire. The proposed methodology includes designing a building structure according to the latest building codes, developing a three-dimensional (3D) finite element method (FEM) computer model to represent building behavior, and conducting incremental …

Analysis Of Data Of Different Spatial Support: A Multivariate Process Approach, Kelly-Ann N. Dixon Hamil

Open Access Dissertations

Inherent to a spatial variable is the unit of support at which it is measured. In many studies, variables are observed at different support. For example, disease rates might be measured at an aggregated level while temperature is usually measured at specific points. It is still an interesting problem to study the relationship of variables having different support. However, it may be a different problem to statistically model the relationship of variables of different support, particularly when the supports do not have a hierarchical structure. Currently, cokriging, the use of one or more spatial variables to predict another variable, is …

Phase Difference Index: A Frequency-Domain Analysis Tool For Structural Mode Identification, Li-Hui Cheng

Open Access Dissertations

A new structural mode-identification approach, called the Phase Difference Index plot (PDI plot), is used to identify the natural modes in a building from its acceleration records response to earthquake ground motion. The phase difference index can be calculated by the Hilbert transform of displacement response curves obtained from acceleration records at two different floors in the building. The torsional mode can also be identified if two accelerometers are installed on opposite sides in a floor. To demonstrate the power of the new approach, earthquake acceleration records from ten buildings in Taiwan and the U.S. are used. After applying narrow …

Exploiting Science: Enhancing The Safety Training Of Pilots To Reduce The Risk Of Bird Strikes, Flavio A.C. Mendonca

Open Access Dissertations

Analysis of bird strikes to aviation in the U.S. from 1990 to 2015 indicate that the successful mitigation efforts at airports, which must be sustained, have reduced incidents with damage and a negative effect-on-flight since 2000. However, such efforts have done little to reduce strikes outside the airport jurisdiction, such as occurred with US Airways Flight 1549 in 2009. There are basically three strategies to mitigate the risk of bird strikes: standards set by aviation authorities, technology, and actions by crewmembers. Pilots play an important role as stakeholders in the prevention of bird strikes, especially outside the airport environment. Thus, …

A Collaborative Monocular Visual Simultaneous Localization And Mapping Solution To Generate A Semi-Dense 3d Map., Ruwan Janapriya Egodagamage

Open Access Dissertations

The utilization and generation of indoor maps are critical in accurate indoor tracking. Simultaneous Localization and Mapping (SLAM) is one of the main techniques used for such map generation. In SLAM, an agent generates a map of an unknown environment while approximating its own location in it. The prevalence and afford-ability of cameras encourage the use of Monocular Visual SLAM, where a camera is the only sensing device for the SLAM process. In modern applications, multiple mobile agents may be involved in the generation of indoor maps, thus requiring a distributed computational framework. Each agent generates its own local map, …

Learning Electron Transport Chain Process In Photosynthesis Using Video And Serious Game, Cecilia Espinoza Morales

Open Access Dissertations

This research investigates students' learning about the electron transport chain (ETC) process in photosynthesis by watching a video followed by playing a serious board game-Electron Chute- that models the ETC process. To accomplish this goal, several learning outcomes regarding the misconceptions students' hold about photosynthesis and the ETC process in photosynthesis were defined. Middle school students need opportunities to develop cohesive models that explain the mechanistic processes of biological systems to support their learning. A six-week curriculum on photosynthesis included a one day learning activity using an ETC video and the Electron Chute game to model the ETC process. The …

Effects Of Acute Aerobic Exercise On Whole Genome Nucleosome Maps, Transcriptomics And Acylcamitine Metabolomics In Skeletal Muscle Of Lean Vs Overweight/Obese Men, Prasad P. Devarshi

Open Access Dissertations

Skeletal muscle mitochondrial dysfunction, evidenced by incomplete beta oxidation and accumulation of fatty acid intermediates in the form of long and medium chain acylcarnitines, may contribute to ectopic lipid deposition and insulin resistance during high fat diet (HFD)-induced obesity. Anterograde and retrograde communication play a role in nucleo-mitochondrial crosstalk that determines skeletal muscle mitochondrial adaptations, specifically alterations in mitochondrial number and function in relation to obesity and insulin resistance. High fat diet (HFD) feeding affects the expression of nuclear-encoded mitochondrial genes (NEMGs) nuclear receptor factor 1 (NRF-1), 2 (NRF-2) and peroxisome proliferator receptor gamma coactivator 1 alpha (PGC-1α) thereby, playing …

Ambient Ionization Mass Spectrometry For Metabolomics And Reaction Acceleration, Caitlin E. Falcone

Open Access Dissertations

This dissertation discusses two interlocking topics: metabolomics by ambient ionization mass spectrometry and reaction acceleration. Ambient ionization mass spectrometry, a fast technique with minimal sample preparation, was used for rapid screening of metabolites. Leaf spray mass spectrometry was proven as a rapid molecular diagnostic tool for emerald ash borer infestation. Leaf spray mass spectrometry was performed on 23 different ash trees to determine that the mass spectra profiles of healthy and infested ash tree leaflets. The discriminator ions of healthy and EAB-infested ash trees were based on principal component analysis and the chemical identities of the discriminator ions were determined …

Materials-Genome-Based Multiscale Modeling Of Ceramics And Laser-Assisted Machining, Xiangyang Dong

Open Access Dissertations

This study is concerned with developing multiscale models to predict material properties and simulate laser-assisted machining of ceramics. The microstructure and composition of ceramics and computational costs are taken into consideration in the development of multiscale models. These models can predict both mechanical and thermal properties, which can further assist in selecting machining parameters for laser-assisted machining of ceramics. Quantum level, atomistic level, micro and macro scales are bridged in the multiscale modeling of ceramics. Interatomic potentials are derived by ab initio methods to achieve more accurate calculations in molecular dynamics (MD) simulations. MD calculations are carried out to predict …

A New Method For Determining Hamaker Constants Of Solids Based On The Dynamic Approach Behavior Of An Atomic Force Microscope, Sean G. Fronczak

Open Access Dissertations

The Hamaker constant, A, is a very important parameter used to quantify the strength of the van der Waals (vdW) attractive interaction among particles and between particles and surfaces. Consequently, an accurate measurement of A is of fundamental importance to a wide range of research and manufacturing fields. Therefore, this dissertation primarily focuses on the development and application of a new method to determine Hamaker constants of solid materials using an atomic force microscope (AFM). While the direct contact or pull-off method is typically employed during an AFM force measurement, this contact-technique is highly dependent upon material properties that are …

A Supervised Learning Approach For Dynamic Sampling (Slads), Gunawath Mudiyanselage Dilshan Prasanjana Godaliyadda

Open Access Dissertations

Sparse sampling schemes can broadly be classified in to two main categories: static sampling where the sampling pattern is predetermined, and dynamic sampling where each new measurement location is selected based on information obtained from previous measurements. Dynamic sampling methods are particularly appropriate for point-wise imaging methods in which pixels are measured sequentially in arbitrary order. Examples of point-wise imaging schemes include certain implementations of atomic force microscopy (AFM), electron back scatter diffraction (EBSD), and Scanning Electron Microscopy (SEM). In these point-wise imaging applications, dynamic sparse sampling methods have the potential to dramatically reduce the number of measurements required to …

Consensus Algorithms For Networks Of Systems With Second- And Higher-Order Dynamics, Michael Fruhnert

Open Access Dissertations

This thesis considers homogeneous networks of linear systems. We consider linear feedback controllers and require that the directed graph associated with the network contains a spanning tree and systems are stabilizable. We show that, in continuous-time, consensus with a guaranteed rate of convergence can always be achieved using linear state feedback. For networks of continuous-time second-order systems, we provide a new and simple derivation of the conditions for a second-order polynomials with complex coefficients to be Hurwitz. We apply this result to obtain necessary and sufficient conditions to achieve consensus with networks whose graph Laplacian matrix may have complex eigenvalues. …

Refresh: An Infrastructure To Build Self-Aware Robotic Systems, Yanzhe Cui

Open Access Dissertations

The programming of most robotic tasks is conceptually simple, but error recovery and the handling of unexpected events add enormous complexity to the programming burden. Furthermore, software is procedural, so the handling of unforeseen scenarios by the programmer is just not possible in most programs. The objective of this dissertation is to describe an infrastructure that guides systems engineers to conveniently program self-aware systems, reducing the workload necessary to program robotic tasks. In this dissertation, we present an infrastructure to enable self-awareness. The primary contributions of the work are four fold. First, an architecture with a programming framework is proposed …

An Optimization-Based Approach To Determine Requirements And Aircraft Design Under Multi-Domain Uncertainties, Parithi Govindaraju

Open Access Dissertations

Determining the optimal requirements for and design variable values of new systems, which operate along with existing systems to provide a set of overarching capabilities, as a single task is challenging due to the highly interconnected effects that setting requirements on a new system’s design can have on how an operator uses this newly designed system. This task of determining the requirements and the design variable values becomes even more difficult because of the presence of uncertainties in the new system design and in the operational environment. This research proposed and investigated aspects of a framework that generates optimum design …

The Effects Of Carbon Dioxide Addition On Turbulent Premixed Combustion, Dong Han

Open Access Dissertations

Turbulent premixed combustion plays an important role in the development of gas turbine systems. Continuous work has been devoted to increasing the turbine inlet temperature regarding thermal efficiency and introducing combustion technology for suppression of pollutants such as nitrogen oxide (NOx). Exhaust gas recirculation (EGR) is recognized as a promising NOx inhibition technique mostly by reducing the combustion temperature. Recent industrial progress showed that EGR significantly reduced NOx emission even at the same turbine inlet temperature. An in-depth understanding of the combustion process is required for the development of low NOx combustors with EGR. In this work, a piloted axisymmetric …

Deceptive Memory Systems, Christopher N. Gutierrez

Open Access Dissertations

Unauthorized data destruction results in a loss of digital information and services, a devastating issue for society and commerce that rely on the availability and integrity of such systems. Remote adversaries who seek to destroy or alter digital information persistently study the protection mechanisms and craft attacks that circumvent defense mechanisms such as data back-up or recovery. This dissertation evaluates the use of deception to enhance the preservation of data under the threat of unauthorized data destruction attacks. The motivation for the proposed solution is two-fold. (i) An honest and consistent view of the preservation mechanisms are observable and often …

Computational Modelling Of Thermal Transport Using Spectral Phonon Boltzmann Transport Equation, Ahmed Osama Ibrahim Hamed

Open Access Dissertations

Lattice vibration is the main microscopic mechanism for thermal transport in dielectric materials. The convenience of the analysis of atomic vibrations in the reciprocal space, motivated by the pioneering work of Debye and Peirels, made phonon transport theory is one of the standard paradigms adequate to study the microstructure and stoichiometry effects on thermal transport phenomena at mesoscale. UO2 is of theoretical as well as technological importance. The characteristic thermal transport phenomena at short length-scale (~ nanometer) and time-scale (~ picosecond) associated with radiation dictate close examination of available theoretical models and solution methods for thermal conductivity prediction, in addition …

Cultivating Asian Students' Willingness To Communicate In American Classrooms Using An Online Video-Based Pre-Arrival Course, Hui-Ching Kayla Hsu

Open Access Dissertations

The purpose of this mixed methods study was: 1) to document the design and implementation process of an online video-based pre-arrival course that was intended to cultivate Asian students’ willingness to communicate in American Classrooms; 2) to assess the effectiveness of the course by measuring students’ oral proficiency and willingness to communicate; and 3) to investigate their first-year classroom participation as well as their experiences with the pre-arrival course. This research inquiry was guided by two research questions: 1) How does completing an online pre-arrival course influence Asian students’ speaking abilities, willingness to communicate, and verbal participation in their first-year …

Axial And Lateral Resistance Of Non-Displacement Piles, Fei Han

Open Access Dissertations

Non-displacement piles have been often used in foundation solutions worldwide due to many advantages, such as their flexible dimensions, the suitabiliy for very hard soil profiles, and the minimal amount of vibration and noise during installation. The thesis focuses on the mechanical response of the pile-soil system when the pile is subjected to vertical or horizontal loads, the mechanisms of the resistance mobilization and the implementation of the research findings in pile design practice.

A series of three-dimesional finite element analyses were performed with an advanced, two-surface constitutive sand model to investigate the response of non-displacement piles to axial loading. …

Radiative Transport And Heavy Ion Collisions, Dustin R. Hemphill

Open Access Dissertations

The good agreement of relativistic, dissipative hydrodynamics with heavy ion experiments at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider seems to indicate that the medium produced in the collision is near local equilibrium. However, the mechanism of the observed rapid equilibration is still an unsolved problem. While elastic 2 → 2 perturbative QCD rates do not quickly thermalize or produce large elliptic fow [1], it has been claimed that perturbative gg ↔ ggg rates can equilibrate rapidly [2]. To investigate rapid equilibration via gg ↔ ggg, the partonic stage of a heavy ion collision is modeled …