Digital Commons Network^™

Development Of Complex Lattice Cell In Benchmark Model Of Particle Bed Critical System, Elijah Chamberlain Lutz

Masters Theses

“Criticality safety benchmark evaluations require the creation of models that most accurately represent the experiment being evaluated. In some cases this can be relatively trivial with experiments containing rather simple or standard geometry. In others, such as packed bed systems, this becomes unique and a more difficult process. The importance of accurate modeling of packed bed systems for the use of criticality safety benchmark evaluations was looked at. Four models were created of various complexities and accuracy. First the multi-particle bed, consisting of a fuel particle (UC_1.7 kernel with C shell) and two filler particles (Zircaloy-4 and C + …

Multiple Generations Of Phlogopite In An Alnöite Diatreme: Insights Into The Petrogenesis Of The Avon Alkaline Igneous Province, Missouri, Nathan Gregory Limbaugh

Masters Theses

“Alkaline Ultramafic Carbonatite (AUC) complexes, although rare, are valued for diamonds and REEs, and as windows into subcontinental and mantle processes as recorded by rock fabrics, mineral spatial relationships, and mineral compositions. We report specifically on olivine and phlogopite petrographic relationships and compositions from the Devonian alnoite diatreme-facies of the Avon Alkaline Igneous Province, Missouri. The diatreme alnoite is a mixture of domains of olivine magmaclasts (OM) set in a crystal-rich melilite matrix. OM are highly fractured, serpentinized olivine pseudomorphs with variable amounts of pristine olivine fragments. Larger olivine domains typically exhibit clear crystal faces and irregular “channels” indicative of …

Investigation Of The Sensitivity Of Human Arm To Small Interaction Forces During Physical Human-Robot Interaction (Phri), Fazlur Rashid

Masters Theses

“Understanding the human motor control strategy during physical interaction tasks is crucial for developing future robots for physical human-robot interaction (pHRI). Effective pHRI depends on humans communicating their intentions for movement with robots. In physical human-human interaction (pHHI), small interaction forces are known to convey their intent between the partners. It is speculated that small interaction forces contain significant information to convey the movement intention of pHHI. However, the mechanism underlying this interaction strategy is largely unknown. Hence, the aim of this work was to investigate what affects humans’ sensitivity to the interaction forces. The hypothesis was that small interaction …

Communicating Uncertain Information From Deep Learning Models To Users, Harishankar Vasudevanallur Subramanian

Masters Theses

“The use of Artificial Intelligence (AI) decision support systems is increasing in high-stakes contexts, such as healthcare, defense, and finance. Uncertainty information may help users better leverage AI predictions, especially when combined with domain knowledge. I conducted two human-subject experiments to examine the effects of uncertainty information with AI recommendations. The experimental stimuli are from an existing image recognition deep learning model, one popular approach to AI. In Paper I, I evaluated the effect of the number of AI recommendations and provision of uncertainty information. For a series of images, participants identified the subject and rated their confidence level. Results …

Computer Gamification: Addressing Symptoms Of Inattentive Adhd In Children, Shavonne Victoria Halterman

Masters Theses

“Computer gamification has the potential to help meet the educational needs of children with Inattentive Attention Deficit/Hyperactivity disorder (ADHD). The elements of computer gamification are mapped to distinct kinds of interventions for Inattentive ADHD and show certain types of computer gamified learning are better than others for those who experience Inattentive ADHD”--Abstract, page iii.

A Compact Wavelength Meter Using A Multimode Fiber, Ogbole Collins Inalegwu

Masters Theses

“Wavelength meters are very important for precision measurements of both pulses and continuous-wave optical sources. Conventional wavelength meters employ gratings, prisms, interferometers, and other wavelength-sensitive materials in their design. Here, we report a simple and compact wavelength meter based on a section of multimode fiber and a camera. The concept is to correlate the multimodal interference pattern (i.e., speckle pattern) at the end-face of a multimode fiber with the wavelength of the input lightsource. Through a series of experiments, specklegrams from the end face of a multimode fiber as captured by a charge-coupled device (CCD) camera were recorded; the images …

Research And Development Of A Laser Hot Wire Deposition Process, Christopher Croft

Masters Theses

“Laser hot wire directed energy deposition (DED) is an increasingly popular method for improving deposition rates and overall reduction of build times in DED processing. While there is clear benefit, it is important to fully understand the impact of preheating the wire. This work focuses on developing a model that describes bead geometry output using all factors including the wire preheat. The model was fit with over 150 data points that explored a large range of each factor. The resulting model was then leveraged to evaluate a process control variable. The technique chosen used feedback from the hot wire system …

Analysis And Design Of Dc-Link Capacitor In Cascaded H-Bridge Multilevel Active Front-End Converter, Muhammad Shehroz Malik

Masters Theses

Medium-voltage grid-tied systems often use a cascaded H-bridge multi-level active front-end. In this converter, dc link bus capacitors play an important role in stabilizing the converter and enabling both active and reactive power injections. The present work provides analytical expressions for the capacitor current, which are essential for optimizing system design (especially capacitor size vs. lifetime). Then, the expression is incorporated into the grid connected bidirectional power system model. Consequently, this work contributes to the guiding principles to choose accurate dc link capacitor ratings against grid-side power delivery requirements.

DC-link capacitors come with an expiration date which is dependent on …

Numerical Behavior Of Steel H-Plies Repaired Using Layered Concrete Jacket, Fareh Waleed Abudawaba

Masters Theses

“This study developed finite element models (FEMs), using LS-Dyna software, to investigate the repair of corroded steel H-piles using concrete jacket. The concrete modeled as a layered material simulating 3D printed concrete. 3DPC is a new technology that can be used to repair or build structures without formwork by depositing concrete mixture layer by layer. For the 3DPC, this study investigated the feasibility of using alkali-activated concrete (AAC) synthesized using class C fly ash as the main binder. The fresh properties, extrudability, and buildability of the proposed concrete were investigated through open time and deformation tests, respectively. Hardened properties were …

Neural Network Supervised And Reinforcement Learning For Neurological, Diagnostic, And Modeling Problems, Donald Wunsch Iii

Masters Theses

“As the medical world becomes increasingly intertwined with the tech sphere, machine learning on medical datasets and mathematical models becomes an attractive application. This research looks at the predictive capabilities of neural networks and other machine learning algorithms, and assesses the validity of several feature selection strategies to reduce the negative effects of high dataset dimensionality. Our results indicate that several feature selection methods can maintain high validation and test accuracy on classification tasks, with neural networks performing best, for both single class and multi-class classification applications. This research also evaluates a proof-of-concept application of a deep-Q-learning network (DQN) to …

Axial Performance Of Self-Consolidating Concrete-Filled Fiber Tubes, Joshua David Carter

Masters Theses

"Concrete filled fiber tubes can be used to increase ductility and strength of a concrete member and self-consolidating concrete is an ideal material to use in practical applications of concrete-filled fiber tubular columns. However, the propensity of self-consolidating concrete to autogenous shrinkage could reduce the effectiveness of the concrete confinement. This research investigates the use of self-consolidating concrete in pre-cast FRP tubes and various methods of shrinkage reduction and compensation to increase the axial performance of said self-consolidating concrete-filled fiber tubes. Axial compression tests were performed under monotonic and cyclic conditions to determine the stress-strain relationship of the self-consolidating concrete …

A Systematic Analysis Of Eye-Tracking Metrics For Sleepiness, Debasis Roy

Masters Theses

”Sleepiness or sleep deprivation is a serious hazard that can be life-threatening in carrying out certain tasks (e.g., when driving or executing attention-critical tasks). Eye movement can provide cues on sleepiness. Hence, eye-tracking metrics have the potential to detect sleepiness.

In this research, we used a systematic analysis approach to identify eye-tracking metrics for sleepiness. We used several databases to identify independent experimental studies that have used eye-tracking metrics to assess sleepiness. We identified 25 studies that included 674 participants where the participants’ data were captured both in an alert state and in a sleep-deprived state. In the analysis, we …

A Meta-Analysis: Gamification In Education, Yalin Wang

Masters Theses

“Gamification has been used in a variety of contexts including education. In order to understand the effects of gamification in education, a meta-analysis was conducted. A bottom-up approach was used to analyze the effects of game design elements on learning outcomes found in the literature search. The result suggests that gamification can enhance student learning outcomes. Elements such as points, leaderboards, competitions, progress bars, feedback, and collaboration have medium to large effect sizes. Gamification also has larger effects on young children in elementary education than learners at other education levels. The study offers suggestions and guidelines for educators on the …

Simulation And Modeling Of Hypersonic Turbulent Boundary Layers Subject To Adverse Pressure Gradients Due To Concave Streamline Curvature, Gary L. Nicholson, Junji Huang, Lian Duan, Meelan M. Choudhari

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct numerical simulations (DNS) of adverse-pressure-gradient turbulent boundary layers over a planar concave wall are presented for a nominal freestream Mach number of 5, with the objective of assessing the limitations of the currently available Reynolds-averaged Navier-Stokes (RANS) models. The wall geometry and flow conditions of the DNS are representative of the experimental data for a Mach 4.9 turbulent boundary layer that was tested on a two-dimensional planar concave wall model in the high-speed blow-down wind tunnel located at the National Aerothermochemistry Laboratory at Texas A&M University (TAMU). The DNS was validated against the experimental results of TAMU for the …

Effect Of Nonlinear Mixing On Electrospray Propulsion Predictions, Mitchell J. Wainwright, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

The Effect Of Laser Welding Modes On Mechanical Properties And Microstructure Of 304l Stainless Steel Parts Fabricated By Laser-Foil-Printing Additive Manufacturing, Chia Hung Hung, Wei Ting Chen, M. Hossein Sehhat, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The success of laser-foil-printing (LFP) additive manufacturing depends critically on the laser welding of sheet metals onto the substrate or the previous layer during the part fabrication process. The welding can be generally categorized into two modes: conduction mode and keyhole mode. In this study, 304L stainless steel parts fabricated by the LFP process using the two laser welding modes are compared. The porosity, microstructure, and tensile properties of the fabricated parts in these two modes are measured and compared in the laser scanning direction (X) and part building direction (Z). The parts fabricated in the conduction mode have a …

Equilibrium And Kinetic Study On The Biosorption Of Trypan Blue From Aqueous Solutions Using Avocado Seed Powder, Tamer T. El-Idreesy, Omar Khoshala, Amin Firouzi, Hany A. Elazab

Chemical and Biochemical Engineering Faculty Research & Creative Works

This research aims to investigate the removal of trypan blue dye from aqueous solutions by employing ground avocado seeds powder, a low-cost biowaste adsorbent (biosorbent), under various experimental conditions. The effect of contact time, initial dye concentration, and adsorbent dose on dye removal were studied. The experimental kinetic data were fitted to pseudo-first order and pseudo-second-order kinetic models. Results imply that adsorption of trypan blue on the avocado seed adsorbent nicely followed the pseudo-second-order kinetic model. Equilibrium isotherms were analyzed by Langmuir and Freundlich isotherms, where Langmuir isotherm described the isotherm data with a high-correlation coefficient (R2=0.9948) closer to unity, …

Electrospun Fiber Scaffolds For Engineering Glial Cell Behavior To Promote Neural Regeneration, Devan L. Puhl, Jessica L. Funnell, Derek W. Nelson, Manoj K. Gottipati, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Electrospinning is a fabrication technique used to produce nano-or micro-diameter fibers to generate biocompatible, biodegradable scaffolds for tissue engineering applications. Electro spun fiber scaffolds are advantageous for neural regeneration because they mimic the structure of the nervous system extracellular matrix and provide contact guidance for regenerating axons. Glia are non-neuronal regulatory cells that maintain homeostasis in the healthy nervous system and regulate regeneration in the injured nervous system. Electro spun fiber scaffolds offer a wide range of characteristics, such as fiber alignment, diameter, surface nano topography, and surface chemistry that can be engineered to achieve a desired glial cell response …

Subsumption Reduces Dataset Dimensionality Without Decreasing Performance Of A Machine Learning Classifier, Donald C. Wunsch, Daniel B. Hier

Chemistry Faculty Research & Creative Works

When Features in a High Dimension Dataset Are Organized Hierarchically, There is an Inherent Opportunity to Reduce Dimensionality. Since More Specific Concepts Are Subsumed by More General Concepts, Subsumption Can Be Applied Successively to Reduce Dimensionality. We Tested Whether Sub-Sumption Could Reduce the Dimensionality of a Disease Dataset Without Impairing Classification Accuracy. We Started with a Dataset that Had 168 Neurological Patients, 14 Diagnoses, and 293 Unique Features. We Applied Subsumption Repeatedly to Create Eight Successively Smaller Datasets, Ranging from 293 Dimensions in the Largest Dataset to 11 Dimensions in the Smallest Dataset. We Tested a MLP Classifier on All …

A Deep Learning Model To Predict Traumatic Brain Injury Severity And Outcome From Mr Images, Dacosta Yeboah, Hung Nguyen, Daniel B. Hier, Gayla R. Olbricht, Tayo Obafemi-Ajayi

Chemistry Faculty Research & Creative Works

For Many Neurological Disorders, Including Traumatic Brain Injury (TBI), Neuroimaging Information Plays a Crucial Role Determining Diagnosis and Prognosis. TBI is a Heterogeneous Disorder that Can Result in Lasting Physical, Emotional and Cognitive Impairments. Magnetic Resonance Imaging (MRI) is a Non-Invasive Technique that Uses Radio Waves to Reveal Fine Details of Brain Anatomy and Pathology. Although MRIs Are Interpreted by Radiologists, Advances Are Being Made in the Use of Deep Learning for MRI Interpretation. This Work Evaluates a Deep Learning Model based on a Residual Learning Convolutional Neural Network that Predicts TBI Severity from MR Images. the Model Achieved a …

Data-Driven Identification Of Governing Partial Differential Equations For The Transmission Line Systems, Yanming Zhang, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Discovering governing equations for transmission line is essential for the study on its properties, especially when the nonlinearity is introduced in a transmission line system. In this paper, we propose a novel data-driven approach for deriving the governing partial differential equations based on the spatial-temporal samples of current and voltage in the transmission line system. The proposed method is based on the ridge regression algorithm to determine the active spatial differential terms from the candidate library that includes nonlinear functions, in which the time and spatial derivatives are estimated by using polynomial interpolation. Three examples, including uniform and nonuniform transmission …

Decoupling Of Antennas With Adjacent Frequency Bands, Min Li, Lijun Jiang, Lawrence Kwan Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

A decoupling device called cascaded power dividing decoupling network (C-PDDN) is presented for two antennas operating in adjacent frequency bands. Design formulas are derived to determine parametrical variables for high isolation. A prototype of a testing array consisting of two base-station dipole antennas is realized on a Rogers PCB for demonstration purposes. Simulated and experimental results show that good impedance matching, and high isolation are achieved simultaneously after adopting the C-PDDN.

Nanostructured Copper Selenide As An Ultrasensitive And Selective Non-Enzymatic Glucose Sensor, Siddesh Umapathi, Harish Singh, Jahangir Masud, Manashi Nath

Chemistry Faculty Research & Creative Works

CuSe nanostructures exhibit high-efficiency for glucose detection with high sensitivity (19.419 mA mM-1 cm-2) and selectivity at a low applied potential of +0.15 V vs. Ag|AgCl, a low detection limit of 0.196 μM and a linear range of glucose detection from 100 nm. to 40 μM. This journal is

Can Mind Perception Explain Virtuous Character Judgments Of Artificial Intelligence?, Daniel Burton Shank, Mallory North, Carson Arnold, Patrick Gamez

Psychological Science Faculty Research & Creative Works

People tend to attribute less of a virtuous or unvirtuous characteristic to artificial intelligence (AI) agents compared to humans after observing a behavior exemplifying that particular virtue or vice. We argue that this difference can be explained by perceptions of experiential and agentic mind. Experiential mind focuses on one's emotions, sensations, and past experiences, whereas agentic mind focuses on one's intentions, capacity for action, and behaviors. Building on person-centered morality, virtue ethics, and mind perception research, we argue that both agentic and experiential mind are possible mediators of behavior-to-character attributions. We conducted two experiments (n = 613, n = 584) …

Humans Are Perceived As Better, But Weaker, Than Artificial Intelligence: A Comparison Of Affective Impressions Of Humans, Ais, And Computer Systems In Roles On Teams, Daniel Burton Shank, Madison Bowen, Alexander Burns, Matthew Dew

Psychological Science Faculty Research & Creative Works

Attributions of affective meaning – goodness, power, and activity – are important for understanding how people interact with both human and technological agents. Recent evidence indicates that labels of artificial intelligence (AI) and computer system differ in affective impressions, but it is unknown if people perceived affective differences when the AI or computer is an agent with a specific human-like role. For humans, roles (e.g., an online recruiter, a product assembling employee, a resource distributor) have stable affective meaning creating a stable social structure and predictable interaction patterns. In this paper, we examine how the 59 roles affectively differ based …

Icelandic Folklore And The Cultural Memory Of Religious Change, Eric Shane Bryan

English and Technical Communication Faculty Research & Creative Works

This book attempts to understand the origins and development of religious belief in Iceland and greater Scandinavia through the lenses of five carefully selected Icelandic folktales collected in Iceland during the nineteenth century. Each of these five stories has a story of its own: a historical and cultural context, a literary legacy, influences from beliefs of all kinds (orthodox and heterodox, elite or lay), and modalities (oral or written) by which the story was told. These factors leave an imprint -- sometimes discernible, sometimes not -- upon the story, and when that imprint is readable, the legacies and influences upon …

Cyclic Sequential Adsorption Desorption/Thermal-Catalytic Oxidation Of Volatile Organic Compounds: Material Development, Process Advancement/Improvement, And Numerical Modeling, Simulation And Optimization, Busuyi Ojo Adebayo

Doctoral Dissertations

"Volatile organic compounds (VOCs) are a group of useful organic chemicals but when emitted have contributed to air pollution. They affect human health, cause environmental degradation and contaminate our waters and soils, so they need to be controlled. When they exist in dilute concentrations, abatement becomes challenging, thus requiring advanced abatement methods, e.g., sequential adsorption desorption/thermal-catalytic oxidation process. The overall goal of this research was to abate dilute streams of VOCs via the process. The specific objectives were to 1) develop novel adsorbent/catalyst dual-function materials (DFMs) for the process, 2) improve the operability of a one-bed-one-column reactor configuration for the …

Identification Of Neuromarkers Using Structural And Functional Neuroimaging, Sreevalsan Sanathanan Menon

Doctoral Dissertations

"One of the grand challenges in science is understanding the human brain. Recent advances in magnetic resonance imaging have opened unmatched opportunities to demystify neural circuitry. In this research, the spatially and temporally complex neuroimaging data were used to identify neuromarkers that aids in quantifying a brain’s health. In the first part, a comparison of static and dynamic functional connectivities was made to study their efficacies in identifying intrinsic individual connectivity patterns. Results show that the intrinsic individual connectivity pattern can be used as a ‘fingerprint’ to distinguish among and identify subjects and their biological sex and is more accurately …

Cooperative Navigation Of Small Satellites In The Deep Space Environment, Jill Christine Davis

Doctoral Dissertations

“The continued development of small satellites (SmallSats) has made them an increasingly viable mission alternative to traditional monolithic spacecraft. Constellations, swarms, and formations of these small spacecraft have the potential to fill unique gaps in the space systems architecture, while reducing overall mission costs and increasing mission redundancy. Cooperative navigation between spacecraft within swarms and formations is critical to mission success, but poses many challenges for SmallSats due to their size, mass, power, and computing constraints. While Earth orbiting missions can rely on GNSS data for high-accuracy inertial and relative navigation, deep space missions require new navigation techniques. In this …

Collaborative Planning In The Construction Industry: A Holistic Framework For Assessing Collaborative Planning Practices And Predicting Project Performance, Amr Elsayegh

Doctoral Dissertations

"The fragmentation of the construction industry prompted developing novel methods such as collaborative planning, lean construction, advancements in technology, integrated project delivery, and relational contracting. Current research focused on specific facets of collaborative planning without presenting a comprehensive analysis of its factors. As such, the goal of this research is to develop a holistic framework that studies and evaluates collaborative planning practices in construction projects. This research offers significant addition to the body of knowledge through various theoretical and practical contributions. In relation to that, this research developed a comprehensive framework by (1) identifying a comprehensive list of factors influencing …