Engineering Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

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. …

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 …

The Use Of Natural Anthraquinone Emodin As A Primary And Complementary Therapeutic In The Treatment Of Colorectal Cancer, Alexander-Jacques Theodore Sougiannis

Theses and Dissertations

5 Fluorouracil (5FU) chemotherapy is widely used in the treatment of colorectal cancer (CRC), and has been the first-choice chemotherapy drug for CRC for many years. However, nearly 10% of patients receiving chemotherapy die during the first 30 days of treatment. Further, it is estimated that 70% of surviving patients will develop non-specific toxicities as a result of chemotherapy treatment. We characterize these toxicities in an animal model of chemotherapy treatment and show that perturbations in the gut microbiome might be exacerbate the prolonged effects of chemotherapy. A compound that could attenuate the multiple non-selective toxicities associated with chemotherapy could …

Local Government Policy And Planning For Unmanned Aerial Systems, Tyler Spence, Francesca Favaro, Kally Yeung

Mineta Transportation Institute

This research identifies key state and local government stakeholders in California for drone policy creation and implementation, and describes their perceptions and understanding of drone policy. The investigation assessed stakeholders’ positions, interests, and influence on issues, with the goal of providing potential policy input to achieve successful drone integration in urban environments and within the national airspace of the United States. The research examined regulatory priorities through the use of a two-tiered Stakeholder Analysis Process. The first tier consisted of a detailed survey sent out to over 450 local agencies and jurisdictions in California. The second tier consisted of an …

The Geographic Disparities In Transportation-Related Physical Activity In The United States: An Analysis Of The 2017 Nhts Data, Hongwei Dong

Mineta Transportation Institute

Research on the relationship between urbanicity and physical activity yielded mixed results despite many studies consistently showing that residents tended to undertake more transportation-related physical activity in a more urban environment. This study analyzed the 2017 NHTS data to examine the geographic disparities in physical activity, particularly transportation-related physical activity in the United States. Our analysis suggests the relationship between urbanicity and physical activity demonstrates a flat U-shape in graphed data. Residents are more physically active when they live in the areas from the two ends of the urbanization spectrum: inner cities and inner suburbs of large metropolitan areas and …

Securing The Emerging Technologies Of Autonomous And Connected Vehicles, Shahab Tayeb, Matin Pirouz

Mineta Transportation Institute

The Internet of Vehicles (IoV) aims to establish a network of autonomous and connected vehicles that communicate with one another through facilitation led by road-side units (RSUs) and a central trust authority (TA). Messages must be efficiently and securely disseminated to conserve resources and preserve network security. Currently, research in this area lacks consensus about security schemes and methods of disseminating messages. Furthermore, a current deficiency of information regarding resource optimization prevents further efficient development of this network. This paper takes an interdisciplinary approach to these issues by merging both cybersecurity and data science to optimize and secure the network. …

Diagnostic Studies Of Non-Thermal Atmospheric Pressure Nanosecond Plasma Jets, Shutong Song

Electrical & Computer Engineering Theses & Dissertations

Non-thermal atmospheric pressure plasma jets attract a lot of attentions due to its growing interest in plasma medicine. In this study, reactive species (e.g. excited He, O, OH) in a helium single-electrode non-thermal atmospheric pressure nanosecond plasma jet (APNPJ) driven by a nanosecond pulsed power supply have been studied via electrical measurements (e.g. voltage, current) and optical emission spectroscopy. It is shown that the gas temperature of the APNPJs remained near 300±50 K by fitting N₂(C-B) second positive system and OH(A-X) emission spectrum. Higher excited N₂+ (by a factor of 1.3) but less excited N_{2 …}

Deep Cellular Recurrent Neural Architecture For Efficient Multidimensional Time-Series Data Processing, Lasitha S. Vidyaratne

Electrical & Computer Engineering Theses & Dissertations

Efficient processing of time series data is a fundamental yet challenging problem in pattern recognition. Though recent developments in machine learning and deep learning have enabled remarkable improvements in processing large scale datasets in many application domains, most are designed and regulated to handle inputs that are static in time. Many real-world data, such as in biomedical, surveillance and security, financial, manufacturing and engineering applications, are rarely static in time, and demand models able to recognize patterns in both space and time. Current machine learning (ML) and deep learning (DL) models adapted for time series processing tend to grow in …

Longitudinal Brain Tumor Tracking, Tumor Grading, And Patient Survival Prediction Using Mri, Linmin Pei

Electrical & Computer Engineering Theses & Dissertations

This work aims to develop novel methods for brain tumor classification, longitudinal brain tumor tracking, and patient survival prediction. Consequently, this dissertation proposes three tasks. First, we develop a framework for brain tumor segmentation prediction in longitudinal multimodal magnetic resonance imaging (mMRI) scans, comprising two methods: feature fusion and joint label fusion (JLF). The first method fuses stochastic multi-resolution texture features with tumor cell density features, in order to obtain tumor segmentation predictions in follow-up scans from a baseline pre-operative timepoint. The second method utilizes JLF to combine segmentation labels obtained from (i) the stochastic texture feature-based and Random Forest …

Synthesis Of Sic Resin For 3d Printing Of Sic Ceramics By Digital Light Processing, Kevin Zhao, Bai Cui

UCARE: Research Products

Silicon carbide (SiC) resin is produced through shear mixing 0.1-1 μm SiC powders with Tethon’s high load Genesis resin base. Resins of varying SiC vol.% were synthesized to test the loading limit of the resin base; 10, 20, and 30 vol.% of SiC were made with the resin base handling the higher loads quite well. Several attempts were made at printing using the Tethon Bison 1000 DLP printer with higher loads of SiC showing better results even with lower intensity UV lights andtimes.

Evaluation Of The Embedded Environmental Impacts Of The Sanitary Sewer System Using Life Cycle Assessment, Kimberly Law

UCARE: Research Products

This study identifies the overall impact that the installation and construction phase of sanitary sewer systems have on the environment. Construction data on sanitary sewer systems from small Nebraska communities was collected and compared to the operating phase of the sanitary sewer. The operating phase is the energy required for the lift station. Analyzing sanitary sewers during their entire life cycle involved the raw materials, infrastructure construction, installation, operation of the system, and maintenance.

Wastewater treatment systems are meant to reduce the negative impact that humans have on the environment. The purpose of the system is to treat and disinfect …

Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique, Dimitar Pashov, Swagata Acharya, Walter R.L. Lambrecht, Jerome Jackson, Kirill Belashchenko, Athanasios Chantis, Francois Jamet, Mark Van Schilfgaarde

Kirill Belashchenko Publications

This paper summarises the theory and functionality behind Questaal, an open-source suite of codes for calculating the electronic structure and related properties of materials from first principles. The formalism of the linearised muffin-tin orbital (LMTO) method is revisited in detail and developed further by the introduction of short-ranged tight-binding basis functions for full-potential calculations. The LMTO method is presented in both Green's function and wave function formulations for bulk and layered systems. The suite's full-potential LMTO code uses a sophisticated basis and augmentation method that allows an efficient and precise solution to the band problem at different levels of theory, …

Estimation Of Lubrication Layer Thickness And Composition Through Reverse Engineering Of Interface Rheometry Tests, Alexis Salinas, Dimitri Feys

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

During concrete pumping, a lubrication layer is formed near the pipe wall. Extensive research has been performed on measuring and modeling the properties of this layer and using these values to predict pumping pressures. However, there are numerous discussions in the literature about the composition and thickness of this layer: can it be considered mortar, a micromortar, or is it cement paste? In this paper, possible solutions for the thickness and composition of the lubrication layer are derived from interface rheometry tests. It is assumed that the lubrication layer is composed of one or more concentric layers of paste or …

7-Dof Robotic Arm Xy-Plane Translational Stability, Christopher Dean Alkire

Doctoral Dissertations and Master's Theses

Robotic arms are traditionally mounted to rigid structures as they perform tasks. As a result, the arm’s movement would not affect the position of its mount and its operational space that it is performing a task within would remain constant. If a robotic arm were to function in orbit, the motion of the arm would cause it to rotate and translate about its center of mass, which changes as the joints of the arm rotate.

The purpose of this thesis is to focus on the two-dimensional translational effects of an arm operating on a simulated zero-friction surface and provide a …

Drones Detection Using Smart Sensors, Aishah Moafa

Doctoral Dissertations and Master's Theses

Drones are modern and sophisticated technology that have been used in numerous fields. Nowadays, many countries use them in exploration, reconnaissance operations, and espionage in military operations. Drones also have many uses that are not limited to only daily life. For example, drones are used for home delivery, safety monitoring, and others. However, the use of drones is a double-edged sword. Drones can be used for positive purposes to improve the quality of human lives, but they can also be used for criminal purposes and other detrimental purposes. In fact, many countries have been attacked by terrorists using smart drones. …

Constrained Motion Analysis And Control Of Spacecraft Asteroid Hovering With Formulation Extension In Geometric Mechanics Framework, Wesley Thomas Stackhouse

Doctoral Dissertations and Master's Theses

This thesis studies the constrained motion for a spacecraft hovering over an asteroid, where the Udwadia-Kalaba (UK) formulation is applied for nominal control, and an adaptive controller is developed to account for unknowns in the dynamics. Then, the formulation is extended in the geometric mechanics framework to account for rigid body spacecraft asteroid hovering. Constraints are developed and applied for fully constrained and under-constrained asteroid hovering. The fully constrained solutions provided by the UK fundamental equation are compared to an optimal linear quadratic regulator. An adaptive controller is designed using the UK fundamental equation as a basis in the form …

Interaction Of High Aspect-Ratio Micro-Pillars With Wall Turbulence, Pratik Suhas Deshpande

Doctoral Dissertations and Master's Theses

An experimental study of the interaction between hairy structures modeled as high-aspect ratio micro-pillars (HAMuP) and wall turbulence is presented. Micro-pillars are elastic, hair-like microstructures which have been inspired by naturally occurring examples like lateral line sensors in fish and air flow sensors in bats. The objective of this thesis was two fold: to develop a manufacturing process for consistent production of HAMuP arrays, and to conduct a study focusing on the interaction of HAMuP arrays with wall turbulence. Hotwire anemometry measurements were carried out in two different experimental facilities at three different streamwise locations to describe the interaction between …

Identifying Opportunities For Educators To Pursue Collaboration At The Interface Of Nursing And Engineering -- And A Word Of Caution, Daniel B. Oerther, Patricia Yoder-Wise, Beverly Malone

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Biphasic Gene Electrotransfer Enhances Gene Delivery In Vitro, John Bui

Biomedical Engineering Theses & Dissertations

The application of short, pulsed electric fields to eukaryotic cells and tissues has been shown to permeabilize cells. This phenomenon has been used for clinical applications for irreversible electroporation of cancer cells or for molecule delivery for drug or gene therapies. Typically, a monophasic (monopolar) pulse train is used; however, recent studies have explored the possibility of using biphasic (often referred to as bipolar) pulses, primarily for irreversible electroporation (IRE), which report reduced muscle contraction during pulse train application compared to monophasic pulses. Additional studies show improved transfection efficiency using biphasic pulses, conversely, with low cell viability. The purpose of …

Lignin: A Likely Precursor Of A Significant Fraction Of Humic Substances Via Oxidative Transformations, Seyyedhadi Khatami

Chemistry & Biochemistry Theses & Dissertations

Lignin is a major component of decaying terrestrial vegetation in soils and has been arguably reported to contribute substantially to the formation of soil carbon humus, and natural dissolved organic matter (DOM). To better understand the process by which this humification occurs, lignin and lignin-derived monomers were subjected to both biotic and abiotic oxidation processes. Two well-known oxidative transformation strategies were employed. The first involved the fungal degradation of brown-rot degraded wood subjected to a white-rot fungus (Phanerochaete chrysosporium) whose enzymes are particularly effective in lignin degradation via enzymatic oxidation. This enzymatic attack was monitored by ultrahigh resolution …

A Post-Impact Behavior Of Platelet-Based Composites Produced By Compression Molding, Christopher Eugene Ervin Volle

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg-based Platelet Molded Compounds (PPMCs) are quickly becoming a widely used method for creating structural components in the aerospace and automotive industries. The discontinuous nature of the platelets used allow good formability of both complex and basic structural components; from seats on commercial airplanes to outer panels of vehicles.

This thesis will look at an important research question of these composites: how PPMCs behave under dynamic loading, e.g. impact and post-impact behavior. Impact is analyzed using recorded force and velocity data to find the absorbed energy. Digital image correlation is used with compression after impact testing to study the propagation …

A Study Of The Aeroacoustics Of Swept Propellers For Small Unmanned Aerial Vehicles, Arthur David Wiedemann

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, small unmanned aerial vehicles (UAVs) have increased in availability and use in both public and commercial sectors. This increased use of small UAVs or “drones” has the unfortunate consequence of introducing excessive noise into communities where they operate. Implementation of noise reduction methods is necessary if we wish to see expanded use of drones in public areas. With electric propulsion, the primary source of noise is the rotor/propeller used in contemporary multi-rotor configurations. In this thesis, the aerodynamics and acoustic behavior of various swept propellers is examined with computational and experimental methods.

A family of propeller geometries …

Investigating The Feasibility And Stability For Modeling Acoustic Wave Scattering Using A Time-Domain Boundary Integral Equation With Impedance Boundary Condition, Michelle E. Rodio

Mathematics & Statistics Theses & Dissertations

Reducing aircraft noise is a major objective in the field of computational aeroacoustics. When designing next generation quiet and environmentally friendly aircraft, it is important to be able to accurately and efficiently predict the acoustic scattering by an aircraft body from a given noise source. Acoustic liners are an effective tool for aircraft noise reduction and are characterized by a frequency-dependent impedance. Converted into the time-domain using Fourier transforms, an impedance boundary condition can be used to simulate the acoustic wave scattering by geometric bodies treated with acoustic liners

This work considers using either an impedance or an admittance (inverse …