Engineering Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

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. …

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 …

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 …

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, …

Design And Testing Of A Supercritical Carbon Dioxide Plasma Reactor, Gregory Belk

Theses and Dissertations

The objective of this project was to design, build, and test a plasma reactor capable of operating in the supercritical conditions. The reactor allows for the initiation of a plasma discharge in different fluids driven by a direct current (DC) power supply operating either in steady state mode or pulsing mode. The reactor was specifically designed for igniting plasmas within supercritical carbon dioxide, which has a pressure of 72.9 atm and 31.1 degrees Celsius.

A series of runs were conducted for varying pressures and inter-electrode separation, which allowed testing the operation regimes of the reactors. Finally, plasma experiments were conducted …

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 …

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 …

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 …

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 …

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 …

Design Of Bio-Inspired Multifrequency Acoustic Sensors And Metamaterial Energy Harvesting Smart Structures, Mohammadsadegh Saadatzi

Theses and Dissertations

Due to the limited availability and high depletion rates of nonrenewable sources of energy as well as environmental concerns, the scientific community has started to explore many alternative clean sources of energies. It is identified that civil, mechanical and Aerospace structures are always subjected to acoustic noises and vibration which could potentially be used as renewable source of energy. Roads and Industrial noise barriers are used inside industrial facilities alongside the walls, around construction pillars, nearby machinery and other equipment to separate quite work zones, protect walls, deliver extra safety and precautions while diminish sound and vibrational pressure. We hypothesized …

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 …

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 …

High-Speed And Low-Power Techniques For Successive-Approximation-Register Analog-To-Digital Converters, Eric Lee Swindlehurst

Theses and Dissertations

Broadband wireless communication systems demand power-efficient analog-to-digital converters (ADCs) in the GHz and medium resolution regime. While high-speed architectures such as the flash and pipelined ADCs are capable of GHz operations, their high-power consumption reduces their attractiveness for mobile applications. On the other hand, the successive-approximation-register (SAR) ADC has an excellent power efficiency, but its slow speed has traditionally limited it to MHz applications. This dissertation puts forth several novel techniques to significantly increase the speed and power efficiency of the SAR architecture and demonstrates them in a low-power 10-GHz SAR ADC suitable for broadband wireless communications. The proposed 8-bit, …

Bacteria In Blood: Optimized Recovery Of Bacterial Dna For Rapid Identification, Ryan Wood

Theses and Dissertations

Blood stream infections are challenging infections to rapidly diagnose. The current clinical diagnostic methods for blood stream infections require culturing the blood sample prior to identifying the bacteria and any resistance the bacteria may contain. Removing the culturing step from the bacterial identification process of a blood stream infection provides a significant reduction in the processing time. However, eliminating the culturing step shifts the difficulty from processing time to concentration, since clinical concentration levels can be as low as 10 CFU/mL in blood. This dissertation developed and evaluated many aspects of the process required to identify bacteria from a blood …

Tracking Multiple Vehicles Constrained To A Road Network Using One Uav With Sparse Visual Measurements, Jared Joseph Moore

Theses and Dissertations

Many multiple target tracking algorithms operate in the local frame of the sensor and have difficulty with track reallocation when targets move in and out of the sensor field of view. This poses a problem when an unmanned aerial vehicle (UAV) is tracking multiple ground targets on a road network larger than its field of view. We propose a Rao-Blackwellized Particle Filter (RBPF) to maintain individual target tracks and to perform probabilistic data association when the targets are constrained to a road network. This is particularly useful when a target leaves then re-enters the UAV’s field of view. The RBPF …

Advancing The Accessibility, Reusability, And Interoperability Of Environmental Modeling Workflows Through Web Services, Xiaohui Qiao

Theses and Dissertations

Global flood forecasting can benefit developing countries and ungauged regions that lack observational data, computational infrastructure, and human capacity for streamflow modeling. Many technical challenges exist to provide flood predictions on a global scale. First, existing land surface forecasts use coarse resolution grid cells, which provide limited information when used for flood forecasting at local scales. There is, so far, no modeling system that can provide rapid and accurate global flood predictions with low cost. Second, accurate flood predictions often require integrating interdisciplinary models, data sources, and analysis routines into a workflow. Limited accessibility, reusability, and interoperability of models restrict …

Relational Database Design And Multi-Objective Database Queries For Position Navigation And Timing Data, Sean A. Mochocki

Theses and Dissertations

Performing flight tests is a natural part of researching cutting edge sensors and filters for sensor integration. Unfortunately, tests are expensive, and typically take many months of planning. A sensible goal would be to make previously collected data readily available to researchers for future development. The Air Force Institute of Technology (AFIT) has hundreds of data logs potentially available to aid in facilitating further research in the area of navigation. A database would provide a common location where older and newer data sets are available. Such a database must be able to store the sensor data, metadata about the sensors, …

Dynamic Micromechanical Fabry-Perot Cavity Sensors Fabricated By Multiphoton Absorption Onto Optical Fiber Tips, Jeremiah C. Williams

Theses and Dissertations

This research leveraged two-photon polymerization microfabrication to integrate dynamic mechanical components with Fabry-Perot resonators onto the ends of low-loss optical fibers to prototype 3 micro-optic devices. The first device featured a multi-positional mirror that enabled thin-film deposition onto cavities of any length with mirrors of significant curvature, for refractive index sensing. The second device combined an FP cavity with a spring body featuring easily scalable stiffness for pressure sensing. The third device presented a high-speed rotating micro-anemometer for measuring a wide range of gas flows. All devices represent a significant reduction in size and weight over commercially available devices.

Sliver: Simulation-Based Logic Bomb Identification/Verification For Unmanned Aerial Vehicles, Jake M. Magness

Theses and Dissertations

This research introduces SLIVer, a Simulation-based Logic Bomb Identification/Verification methodology, for finding logic bombs hidden within Unmanned Aerial Vehicle (UAV) autopilot code without having access to the device source code. Effectiveness is demonstrated by executing a series of test missions within a high-fidelity software-in-the-loop (SITL) simulator. In the event that a logic bomb is not detected, this methodology defines safe operating areas for UAVs to ensure to a high degree of confidence the UAV operates normally on the defined flight plan. SLIVer uses preplanned flight paths as the baseline input space, greatly reducing the input space that must be searched …

Modeling Nonlinear Heat Transfer For A Pin-On-Disc Sliding System, Brian A. Boardman

Theses and Dissertations

The objective of this research is to develop a numerical method to characterize heat transfer and wear rates for samples of Vascomax® 300, or Maraging 300, steel. A pin-on-disc experiment was conducted in which samples were exposed to a high-pressure, high-speed, sliding contact environment. This sliding contact generates frictional heating that influences the temperature distribution and wear characteristics of the test samples. A two-dimensional nonlinear heat transfer equation is discretized and solved via a second-order explicit finite difference scheme to predict the transient temperature distribution of the pin. This schematic is used to predict the removal of material from the …