Engineering Commons^™

Influence Of Coordination Environment On Catalyst Structure And Function For Co2 Hydrogenation And Ethane Partial Oxidation, Juan D. Jimenez

Theses and Dissertations

In this work, we set out to establish strong structure/activity relationships for various catalytic compositions and reactions. Through in situ spectroscopic approaches, specifically DRIFTS, Raman XPS, and XAFS, we were able to discern the reactive species in CO₂ hydrogenation over highly active cobalt nanostructures, the relevant ensemble size and composition of single site catalysts for CO₂ hydrogenation, and active vibrational modes of mixed oxide catalysts for ethane partial oxidation (EPO).

First, we illustrate how tailoring surface orientations of Co₃O₄ catalysts on the nanoscale results in control over catalytic performance via the preferential formation of active …

Multi-Scale Modeling For Transport Study Inside Porous Layers Of Polymer Electrolyte Membrane Fuel Cell Using Direct Numerical Simulation, Pongsarun Satjaritanun

Theses and Dissertations

The direct modeling-based Lattice Boltzmann Agglomeration Method (LBAM) is used to explore the electrochemical kinetics and multi-scalar/multi-physics transport inside the detailed structure of the porous and catalyst layers inside polymer electrolyte membrane fuel cells (PEMFCs). The complete structure of the samples is obtained by both micro- and nano- X-ray computed tomography (CT). LBAM is able to predict the electrochemical kinetics in the nanoscale catalyst layer and investigate the electrochemical variables during cell operation. This work shows success in integrating the lattice elements into an agglomerate structure in the catalyst layer (CL). The predictions using LBAM were compared and validated with …

Parsimonious Sociology Theory Construction: From A Computational Framework To Semantic-Based Parsimony Analysis, Mingzhe Du

Theses and Dissertations

In the social sciences, theories are used to explain and predict observed phenomena in the natural world. Theory construction is the research process of building testable scientific theories to explain and predict observed phenomena in the natural world. Conceptual new ideas and meanings of theories are conveyed through carefully chosen definitions and terms.

The principle of parsimony, an important criterion for evaluating the quality of theories (e.g., as exemplified by Occam’s Razor), mandates that we minimize the number of definitions (terms) used in a given theory.

Conventional methods for theory construction and parsimony analysis are based on heuristic approaches. However, …

Using Human Granulosa Cells To Select The Most Competent Embryos For Uterine Transfer In In Vitro Fertilization Cycles, Richard John Kordus

Theses and Dissertations

Infertility is a worldwide epidemic often treated with in vitro fertilization. The success of in vitro fertilization is directly dependent upon the quality of oocytes produced during the controlled stimulation of the patient’s ovaries. There is a need for improved methods to allow embryologists to select the most viable embryos with the highest probability of leading to live births since in vitro fertilization success is far from optimal.

Oocyte and subsequent embryo quality are intimately influenced by the granulosa cells which surround the oocyte during follicular maturation. The oocytes require proper signaling and energy production form the surrounding granulosa cells …

Lablineup: An Intuitive Web Application For Queueing Help Requests In Academic Labs, Graham Mcdonald

Senior Theses

LabLineup is a start-up project designed to address the needs of large, lab-based classes, where teaching assistants (TAs) struggle to assist students in the order in which they request help. LabLineup is a lightweight web application that allows TAs and professors to accept requests for help in order. LabLineup allows professors to view the requests for a lab and see frequently asked questions that can be addressed en masse rather than individually. LabLineup also allows students to provide TA feedback. LabLineup addresses issues arising from requesting help in large, lab-based classes in the most efficient manner possible.

Tow-Path Characterization For Automated Fiber Placement, Roudy Wehbe

Theses and Dissertations

Automated Fiber Placement (AFP) is a manufacturing process used to fabricate large composite structures for aerospace applications. During the process, the machine head deposits multiple bands of composite material named tows over a prescribed path. Temperature, speed, and compaction pressure can be varied to obtain a good layup quality. For conventional laminated plate structures manufactured using the AFP process, fibers are laid at constant angles (0°, 90°, ±45°) in straight paths. However, to manufacture complex shell structures or variable stiffness plates, curved paths are necessary in the design leading to a length mismatch between the parallel edges of the towpath. …

Seismic Attribute Fracture Analysis And Thin And Thick-Skinned Structural Controls On The Evolution Of A Foreland Basin - Parrando And Guavio Anticlines, Eastern Cordillera Foothills, Colombia, Ibraheem Khalil Hafiz

Theses and Dissertations

The Parrando and Guavio anticlines are located in the Llanos foothills on the eastern flank of the Eastern Cordillera of Colombia. This study presents new 3D horizon maps, seismic and stratigraphic interpretations, and 1D burial models based on a 3D seismic volume, 2D seismic lines, and well logs. The Guavio anticline was formed by overlapping Miocene-Pliocene fault-bend folds and inversion of the Guaicaramo normal fault. Unlike previous models, the basement fold is interpreted as formed by a ramp from pre-Cretaceous basement to a double wedge fault probably preceded by a thin-skinned bedding plane thrust fault. A new 1D burial model …

Optimization Of Vehicle To Grid System In A Power System With Unit Commitment, Charles Uko

Theses and Dissertations

This thesis provides a comprehensive overview and analysis of the benefits of using plug-in electric vehicles (PEVs) in solving the unit commitment problem. PEVs are becoming more attractive and a rapid replacement of conventional fuel vehicles due to their environmental-friendly operation. Through collective control by an aggregator, PEVs batteries can also provide ancillary services such as load leveling and frequency regulation to improve the quality of power supplied in the power grid and reduce the cost of power generation. This study presents the modeling, simulation, and analysis of a vehicle-to-grid (V2G) system connected to a smart power grid. The model …

Structural Design Of Pool House In The City Of Columbia, Nathan F. Gates

Senior Theses

This report presents a structural design for a one-story pool house in the City of Columbia. The most important part of the project was determining critical horizontal and vertical loads, and designing each member in accordance to those governing loads. The loads we analyzed were dynamic, dead, live and seismic. By means of the LRFD method, the greatest possible load combination was calculated, combining the previously mentioned loads. These load combinations were different for each analysis, as the loading pressures will change depending on what structural system is being analyzed. This comprises the large part of the report and of …

Design And Control Of An Arrayed Infrared (Mat-Ir) Heater For Accurate Heating Control During Automated Fiber Placement, Benjamin L. C. Greenberg

Theses and Dissertations

Automated Fiber Placement (AFP) is the primary method for manufacturing of large and complex primary composite structures in the aerospace industry. Predominantly, AFP use infrared heaters to ensure appropriate tackiness between the different composite layers. The task of accurately detecting and obtaining a set uniform temperature, across the nip point/line, has proven to be difficult. Traditional AFP heat processes are mostly open-loop controlled, which can lead to issues with ensuring accurate and uniform heat distributions. The latter need to be obtained to allow for proper material consolidation to occur. Uneven heating could cause degradation at the center or at the …

Kinetic And Multidimensional Transport Coupled Numerical Investigation Of Nox Formation During Syngas And Natural Gas Combustion, Sheikh Farhan Ahmed

Theses and Dissertations

The primary objective of this thesis work is focused on the chemical kinetic modeling of the formation of Oxides of Nitrogen (collectively termed as NOx), regarded as a major pollutant emitted by combustion devices, and the application of that model to simulate transport coupled multidimensional distribution of NOx in a reacting flow. The underlying motivation of this kinetic modeling is the noted discrepancies among the existing models, which become critical in selecting the correct model in advanced gas turbine and engine research. The first part of this work is the performance evaluation and comparison of the existing models. Based on …

The Role Of Acute And Chronic Neuroinflammation In Depression: Uncovering The Relationship Between Histamine And Serotonin Transmission, Melinda Hersey

Theses and Dissertations

Depression is the leading cause of disability worldwide. Disorders of the brain, including depression, are notoriously difficult to treat because the basic pathology underlying behavioral outcomes remains undefined. Robust chemical biomarkers of these diseases have not been identified, nor are there reliable methods to measure brain chemicals. Depression is associated with chemical and inflammatory changes in the brain that are predicted to contribute to the pathology. By studying the serotonin and histamine systems we aim to better define the neurochemical basis of depression. Serotonin has long been hypothesized to play a role in depression since selective serotonin reuptake inhibitors (SSRIs) …

Effect Of Cannabinoid Treatment On Immune Cell Functions During Acute Lung Injury, Amira Kamil Mohammed

Theses and Dissertations

Staphylococcal enterotoxin B (SEB) is a highly potent CDC select agent that can trigger acute lung injury (ALI) via robust T cell proliferation and differentiation, and massive cytokine and chemokine release. Δ9-Tetrahydrocannabinol (THC) is a psychoactive ingredient found in Cannabis sativa. In the current study, we investigated the effects of treatment with THC on SEB-induced acute lung injury. To this end, acute lung injury was induced by a dual dose of SEB in C3H/HeJ mice, which were then treated with vehicle or THC. THC-treatment led to survival of all the SEB-administered mice when compared to vehicle-treated. This corroborated with THC-induced …

The Manufacturing And Characterization Of Pseudo-Woven Carbon Fiber Composite Architectures For Enhanced Damage Tolerance, Cyrus Vakili Rad

Theses and Dissertations

Traditional unidirectional carbon fiber reinforced polymer matrix composites exhibit brittle failure, limited toughness, and poor damage tolerance often resulting in the overdesign of composite systems. This work focuses on the automated fiber placement (AFP) manufacturing and characterization of a new family of pseudo-woven (PW) laminate architectures aimed to enhance impact resistance and damage tolerance. The PW laminate architecture uses a specialized in situ AFP process implementing tow skips to produce its laminate architecture. This results in a heterogeneous architecture possessing spatially variable in-plane material properties unlike traditional laminated composites. This heterogeneity is associated with topological variations in the fiber orientations …

Efficient Design Optimization Methodology For Manufacturable Variable Stiffness Laminated Composite Structures, Mazen Albazzan

Theses and Dissertations

Because of their superior mechanical and environmental properties compared to traditional metals, fiber-reinforced composite materials have earned a widespread acceptance for different structural applications. The tailoring potential of composites to achieve high specific stiffness and strength has promoted them as promising candidates for constructing lightweight structures. From that aspect, designers have tackled the problem of designing composite laminates, which is inherently challenging due to the presence of non-linear, non-convex, and multi-dimensional optimization problems with discrete and continuous design variables. However, despite their increased usage, the possible improvements that can be achieved by composite laminates have not been fully exploited. With …

Acoustic Emission And Guided Wave Modeling And Experiments For Structural Health Monitoring And Non-Destructive Evaluation, Roshan Prakash Joseph

Theses and Dissertations

This dissertation is organized into major parts. In Part I of the dissertation, plate guided waves due to an acoustic emission (AE) event are analytically studied in the context of seismic moment tensor sources. The guided wave propagation elastodynamic equation corresponding to a point source applied to the plate in an arbitrary direction is modified in order to describe the case when the source is a seismic moment tensor of various tensor components. This part of the dissertation also discusses the analytical modeling of AE test sources such as pencil lead break, hammer hit excitation, etc.

In Part II of …

Structural Evolution Of La Florida And Guavio Anticlines, Fractures, And Petroleum Systems In A Foreland Fold Belt, Eastern Cordillera Foothills, Colombia, Ziyad Albesher

Theses and Dissertations

Geological structures and petroleum systems associated with La Florida anticline and the Cusiana fault system in the Llanos foothills and the Guavio anticline and the Guaicaramo fault system in the Medina basin were interpreted based on 3D seismic data from La Florida anticline in the foothills, 2D seismic data in the Medina basin and Guavio anticline, well, and surface geology maps. Unlike previous interpretations of the Guavio anticline and Medina basin area, our interpretation shows that thin-skinned thrusting on the Guaicaramo fault preceded thick-skinned basement thrusting. Late Miocene thin-skinned ramp thrusting was followed by a Pliocene thick-skinned fault-bend fold ramping …

Channel Modeling And Tropospheric Effects On Millimeter Wave Communications For Aviation Applications, Jinwen Liu

Theses and Dissertations

Next generation communication systems will be designed to be faster, more secure and easier to connect with than current systems. Along with the concept of internet of things (IoT), many more devices will be required to communicate with each other. In the case of aeronautical vehicles and systems, in addition to current navigation and surveillance systems, more data links will be required for multiple applications, such as photography, inspections, and entertainment. Current aviation frequency bands will likely be unable to support all proposed services. Apart from air-to-ground (AG) communication links, airport surface terrestrial links and satellite-to-air links (SA) are also …

Nitric Oxide Expression With Age And Diet In The Arterial Wall Of Apoe Knockout Mice, Kara Cooper

Theses and Dissertations

Background: Hypertension is a dangerous condition that precedes many cardiovascular events including myocardial infarction, stroke, transient cerebral ischemic attack and symptomatic aortoiliac occlusive disease. While it is universally accepted that arteries stiffen with age, the physiological reason for this is debated. In a previous study, by Dr. Shana Roach Watson it was shown that collagen fibers re-orient themselves in a circumferential direction, resulting in increased arterial stiffness. The study hypothesized that this collagen remodeling could be a result of decreased nitric oxide production.

Methods: This study measured nitric oxide in two different ways, indirectly via Immunoperoxidase staining for eNOS and …

Effects Of Material Characteristics And Equipment Configuration On Profilometry Scanning Results For Error Mitigation In Automated Fiber Placement, Jacob Ondeck

Theses and Dissertations

The Automated Fiber Placement manufacturing process is a method for constructing layered composite parts. This is done by placing tapes of material on a tool using a compaction roller and heat to tackify the material [1]. This manufacturing process is not new, but latest equipment generations can still introduce randomly occurring defects, presenting often as tow twists, gaps, unintentional overlaps and even missing tows during the layup process. These defects deviate the manufactured structure from the as-designed structure, and have been proven to introduce stress concentration sources, which can ultimately undermine the performance of a structure [2]. To detect and …

Advanced Geometric Analyses In Vascular Disease And Interventions, Dara Ahmadi Azar

Theses and Dissertations

The central function of the vascular system is the transportation and distribution of blood throughout the body. Occurrence of various forms of vascular disease, in which this central function is compromised, is associated with high mortality and morbidity rates. Vascular disease is an active and multifactorial process causing changes in local hemodynamics and blood vessel wall mechanics. The work presented here aims to advance the current knowledge on the role of local geometrical parameters in vascular disease and endovascular intervention modalities. In our first set of studies, we develop a computational framework to understand the role of aortic geometry in …

A Machine Learning Based Approach To Accelerate Catalyst Discovery, Asif Jamil Chowdhury

Theses and Dissertations

Computational catalysis, in contrast to experimental catalysis, uses approximations such as density functional theory (DFT) to compute properties of reaction intermediates. But DFT calculations for a large number of surface species on variety of active site models are resource intensive. In this work, we are building a machine learning based predictive framework for adsorption energies of intermediate species, which can reduce the computational overhead significantly. Our work includes the study and development of appropriate machine learning models and effective fingerprints or descriptors to predict energies accurately for different scenarios. Furthermore, Bayesian inverse problem, that integrates experimental catalysis with its computational …

Geophysical Study Of Gold Mineralized Zones In The Carolina Terrane Of South Carolina, Saad Saud Alarifi

Theses and Dissertations

T

he goal of this study was to calibrate and test geophysical methods for the detection of geological structural and disseminated sulfides in the area of the four largest gold deposits in the Southern Appalachian of South Carolina. The Coastal plain sediments, vegetation and saprolite covering the mining areas remain the most challenging in this region. The work focused on the calibration of high-resolution gravity, and helicopter electromagnetic (EM) and magnetic data provided by OceanaGold over the Haile and Brewer Mines; then calibrating the regional gravity and aeromagnetic data over the four gold mines in South Carolina. Observed geophysical fields …

An Overlay Architecture For Pattern Matching, Rasha Elham Karakchi

Theses and Dissertations

Deterministic and Non-deterministic Finite Automata (DFA and NFA) comprise the fundamental unit of work for many emerging big data applications, motivating recent efforts to develop Domain-Specific Architectures (DSAs) to exploit fine-grain parallelism available in automata workloads.

This dissertation presents NAPOLY (Non-Deterministic Automata Processor Over- LaY), an overlay architecture and associated software that attempt to maximally exploit on-chip memory parallelism for NFA evaluation. In order to avoid an upper bound in NFA size that commonly affects prior efforts, NAPOLY is optimized for runtime reconfiguration, allowing for full reconfiguration in 10s of microseconds. NAPOLY is also parameterizable, allowing for offline generation of …

Automation Of Process Planning For Automated Fiber Placement, Joshua A. Halbritter

Theses and Dissertations

Process planning represents an essential stage of the Automated Fiber Placement (AFP) workflow. It develops useful and efficient machine processes based upon the working material, composite design, and manufacturing resources. The current state of process planning requires a high degree of interaction from the process planner and could greatly benefit from increased automation. Therefore, a list of key steps and functions are created to identify the more difficult and time-consuming phases of process planning. Additionally, a set of metrics must exist by which to evaluate the effectiveness of the manufactured laminate from the machine code created during the Process Planning …

Strain Components In Friction Stir Extrusion, Megan Ryan

Theses and Dissertations

Friction stir extrusion is a solid state process that uses a rotating die to perform extrusions. This process can be used to directly recycle waste from machining processes and has been shown to produce wires with desirable mechanical properties. In order to better understand the friction stir extrusion process, the effect of the process parameters on the strain distribution in the wires needs to be understood. The process parameters evaluated in this work are die advance rate, die rotational seed, and die geometry. A total of 16 wires were extruded using different combinations of these process parameters. Marker wires were …

Influence Of Dynamic Multiaxial Transverse Loading On Ultrahigh Molecular Weight Polyethylene Single Fiber Failure, Frank David Thomas

Theses and Dissertations

High performance fibers such as ultrahigh molecular weight polyethylene (UHMWPE) are often used for ballistic impact applications in the form of textile fabrics and composite laminates. In order to predict the ballistic performance of such materials, single-fiber experiments are performed to quantify the material behavior at smaller length scales, which can be applied to larger length scales as a result. Failure of UHMWPE is well understood as a function of simple tension at low and high strain rates, as well as under various multiaxial loading states. However, experimental characterization of single UHMWPE fibers under transverse loading at high strain rates …

The Development Of Polymer Constructs For Adipose Tissue Engineering Applications, Kendall Murphy

Theses and Dissertations

The adipose tissue functions as the body’s main energy reservoir and plays a central role in maintaining whole body energy homeostasis. The ability to modulate this tissue’s inherent endocrine and metabolic functions has promising implications in treating disease associated with adipose tissue dysfunction. This work revolves around two diseases where adipose tissue inflammation and metabolic dysfunction drive the disease, obesity and cachexia. Both diseases impact a significant population of U.S. adults and substantially reduce patient quality of life.

In this study, we first demonstrate the use of novel therapeutic platforms engineered to specifically target adipose tissue inflammation and lipid catabolism …

Analyzing And Learning The Language For Different Types Of Harassment, Mohammadreza Rezvan, Saeedeh Shekarpour, Faisal Alshargi, Krishnaprasad Thirunarayan, Valerie L. Shalin, Amit P. Sheth

Publications

THIS ARTICLE USES WORDS OR LANGUAGE THAT IS CONSIDERED PROFANE, VULGAR, OR OFFENSIVE BY SOME READERS. The presence of a significant amount of harassment in user-generated content and its negative impact calls for robust automatic detection approaches. This requires the identification of different types of harassment. Earlier work has classified harassing language in terms of hurtfulness, abusiveness, sentiment, and profanity. However, to identify and understand harassment more accurately, it is essential to determine the contextual type that captures the interrelated conditions in which harassing language occurs. In this paper we introduce the notion of contextual type in harassment by distinguishing …

Knowledge Infused Learning (K-Il): Towards Deep Incorporation Of Knowledge In Deep Learning, Ugur Kursuncu, Manas Gaur, Amit Sheth

Publications

Learning the underlying patterns in data goes beyondinstance-based generalization to external knowledge repre-sented in structured graphs or networks. Deep learning thatprimarily constitutes neural computing stream in AI hasshown significant advances in probabilistically learning la-tent patterns using a multi-layered network of computationalnodes (i.e., neurons/hidden units). Structured knowledge thatunderlies symbolic computing approaches and often supportsreasoning, has also seen significant growth in recent years,in the form of broad-based (e.g., DBPedia, Yago) and do-main, industry or application specific knowledge graphs. Acommon substrate with careful integration of the two willraise opportunities to develop neuro-symbolic learning ap-proaches for AI, where conceptual and probabilistic repre-sentations are combined. …