Engineering Commons^™

Multi-Hazard Vulnerability Assessment Of Monopile Foundation Offshore Wind Turbines, Jharna Pokhrel

Electronic Theses and Dissertations

Offshore Wind Turbines (OWTs) have increased in popularity because of numerous technological advancements in the sector of renewable energy. With such an increase in the number of installments, there is a need for multi-hazard vulnerability assessment of the OWT at a given site. Because of hurricane and tsunami loads pertaining to the offshore site, structural failure analysis with respect to wind and wave loads at the critical section of the OWT is required. The existing simulation methods for the failure assessment are computationally expensive and require many simulations to estimate the multi-hazard behavior. The goal of this thesis was to …

Set-Theoretic Model Reference Adaptive Control Of A Generic Transport Model, Ehsan Arabi, Tansel Yucelen, Nhan T. Nguyen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper illustrates an application of a recently developed set-theoretic model reference adaptive control architecture on a generic transport model developed by NASA. The set- theoretic model reference adaptive control allows the system error bound between the state of an uncertain dynamical system and the state of a given reference model to be less than a-priori, user-defined worst-case performance bound. Thus, it has the capability to enforce strict performance guarantees to the adaptively controlled uncertain dynamical systems. specifically, after designing set-theoretic adaptive controllers for both longitudinal and lateral-directional dynamics here, the efficacy of this architecture is illustrated on the NASA …

Linear Burn Rate Of Monopropellant For Multi-Mode Micropropulsion, Alex J. Mundahl, Steven P. Berg, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-mode micro propulsion is a technology that can enable rapidly composable small satellites with unprecedented mission flexibility. To maximize mission flexibility a multi-mode micro propulsion monopropellant must be shared between the chemical and electric propulsion modes. Previous research has identified a promising monopropellant that is both readily catalytically exothermically decomposed (chemical mode) and electro sprayable (electric mode). In this work the linear burn rate of this monopropellant is determined and used to aid the design of a microtube catalytic chemical thruster. Experiments with a pressurized fixed volume reactor are used to determine the linear burn rate. Benchmark experiments use a …

Electrospray Mass Spectroscopy Of A Han-Based Monopropellant, Mitchell J. Wainwright, Joshua L. Rovey, Shawn W. Miller, Benjamin D. Prince, Steven P. Berg

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A mixture of [Emim][EtSO4]-HAN is a potential propellant suitable in a multi-mode chemical-electric microtube-electrospray micro propulsion system. This paper reports experimental mass spectrum results for this liquid when electro sprayed in a 50 μm capillary emitter. Mass spectra from 0-600 amu were obtained over a variety of angles and flow rates from 2 pL/sec to 3 nL/sec in both cation and anion extraction mode. Effects of flow rate and angular orientation on the spectra agree well with literature. Results show at least three of the four monomer species are emitted, along with numerous other species, some of which have been …

Papers Of E. A. Seamands Arc1984-004 - Finding Aid, Ats Special Collections And Archives

Finding Aids

No abstract provided.

Adaptive Methods For Point Cloud And Mesh Processing, Zinat Afrose

Computational Modeling & Simulation Engineering Theses & Dissertations

Point clouds and 3D meshes are widely used in numerous applications ranging from games to virtual reality to autonomous vehicles. This dissertation proposes several approaches for noise removal and calibration of noisy point cloud data and 3D mesh sharpening methods. Order statistic filters have been proven to be very successful in image processing and other domains as well. Different variations of order statistics filters originally proposed for image processing are extended to point cloud filtering in this dissertation. A brand-new adaptive vector median is proposed in this dissertation for removing noise and outliers from noisy point cloud data.

The major …

Inverse Kinematic Assessment Of Rehabilitative Therapy In Children Using Orthotics, Michael P. Murphy, Jacob R. Rammer, Kaleb L. Vinohout, Meghan R. Caballero, Christy M. Cornwell, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Pathologic movement patterns are characterized by abnormal kinematics that alter how muscles support the body during walking. Individual muscles are often the target of interventions with physical therapy and surgery alike, yet the tools to assess individual muscles clinically remain limited. The aim of this study is to assess OpenSim as a clinical tool for individualized rehabilitative evaluation of children using orthotics. This anatomic and kinematic modeling study was focused on pre- and post-treatment assessment of gait characteristics in fourteen children using orthotic devices. A range of four to twelve acceptable gait capture trials was collected for each child before …

Applying Convolutional Neural Networks For The Source Reconstruction, He Ming Yao, Wei E.I. Sha, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a novel source reconstruction method (SRM) based on the convolutional neural network algorithm. The conventional SRM method usually requires the scattered field data oversampled compared to that of target object grids. To achieve higher accuracy, the conventional SRM numerical system is highly singular. To overcome these difficulties, we model the equivalent source reconstruction process using the machine learning. The equivalent sources of the target are constructed by a convolutional neural networks (ConvNets). It allows us to employ less scattered field samples or radar cross section (RCS) data. And the ill-conditioned numerical system is effectively avoided. Numerical examples …

Proceedings Of The 18th Annual Early Career Technical Conference (Front Matter), Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the 18th Annual Early Career Technical Conference, November 3, 2018. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama; pp. i-xii

Section 3: Miscellaneous, Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the 18th Annual Early Career Technical Conference, November 3, 2018. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama; pp. 71-90

Effect Of Screen Layers And Orientations On Mesh Wicked Heat Pipes, K Kaddoura, O Y W Abotsi, John Kizito

Early Career Technical Journal (ECTJ)

Section 1: Thermal Sciences; pp. 27-32

Numerical Predictions Of Hydrokinetic Turbine Wake And Freesurface Signatures, Oumina El Fajri, Simon Bushan, D Thompson

Early Career Technical Journal (ECTJ)

Section 2: Numerical Methods; pp. 43-51

Application-Adaptable Chipless Rfid Tag, Katelyn Brinker, Reza Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Chipless RFID has gained prominence due to its application versatility and cost and complexity advantages over traditional RFID. However, chipless RFID tags are typically designed for a specific application instead of being deployable for a multitude of applications. In this paper, a new approach to adaptable chipless RFID tag is proposed that can be optimized for a variety of applications, including materials characterization with tags as embedded sensors. Additionally, the designed approach renders tags that can be interrogated with a linearly polarized probe and achieves bit densities up to 27.57 bits/cm 2,

Synchrotron Radiation X-Ray Absorption Spectroscopy And Spectroscopic Ellipsometry Studies Of Insb Thin Films On Gaas Grown By Metalorganic Chemical Vapor Deposition, Yingda Qian, Yuanlan Liang, Xuguang Luo, Kaiyan He, Wenhong Sun, Hao Hsiung Lin, Devki N. Talwar, Ting Shan Chan, Ian Ferguson, Lingyu Wan, Qingyi Yang, Zhe Chuan Feng

Electrical and Computer Engineering Faculty Research & Creative Works

A series of ultrathin InSb films grown on GaAs by low-pressure metalorganic chemical vapor deposition with different V/III ratios were investigated thoroughly using spectroscopic ellipsometry (SE), X-ray diffraction, and synchrotron radiation X-ray absorption spectroscopy. The results predicted that InSb films on GaAs grown under too high or too low V/III ratios are with poor quality, while those grown with proper V/III ratios of 4.20-4.78 possess the high crystalline quality. The temperature-dependent SE (20-300°C) and simulation showed smooth variations of SE spectra, optical constants (n, k, e1, and ϵ2), and critical energy points (E1, E1+Δ1, E′0, E2, and E′1) for InSb …

Design Optimization Of A Non-Axisymmetric Endwall Contour For A High-Lift Low Pressure Turbine Blade, Jacob Allen Dickel

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Various approaches have been used to shape the geometry at the junction of the endwall and the blade profile in high-lift low-pressure turbine passages in order to reduce the endwall losses. This thesis will detail the workflow to produce an optimized non-axisymmetric endwall contour design for a front-loaded high-lift research turbine profile. Validation of the workflow was performed and included a baseline planar and test contour case for a future optimization study. Endwall contours were defined using a series of Bezier curves across the passage to create a smooth surface. A parametric based approach was used to develop the test …

3d Visualization And Interactive Image Manipulation For Surgical Planning In Robot-Assisted Surgery, Mohammadreza Maddah

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Robot-assisted surgery, or "robotic" surgery, has been developed to address the difficulties with the traditional laparoscopic surgery. The da Vinci (Intuitive Surgical, CA and USA) is one of the FDA-approved surgical robotic system which is widely used in the case of abdominal surgeries like hysterectomy and cholecystectomy. The technology includes a system of master and slave tele-manipulators that enhances manipulation precision. However, inadequate guidelines and lack of a human-machine interface system for planning the ports on the abdomen surface are some of the main issues with robotic surgery. Unreachable target and mid-surgery collisions between robotic arms are the major problems …

Coupling Computational Fluid Dynamics Analysis And Optimization Techniques For Scramjet Engine Design, Nathan T. Mcgillivray

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Various aspects of hypersonic vehicles are being rapidly explored for improved functionality. One of the main areas of consideration is the fueling of a Supersonic Combusting Ramjet (scramjet) engine. Using Computational Fluid Dynamics (CFD), computer simulations can be performed to analyze the flow physics of a scramjet. In this research, an optimization code, Dakota, is integrated with the CFD to optimize a set of parameters to maximum thrust. In this study, the fuel injection and combustion is replaced with heat sources. This simplification greatly reduces the computational requirements. Additionally, the 3D geometry is reduced to an axisymmetric 2D geometry because …

Analysis Of Evolutionary Algorithms In The Control Of Path Planning Problems, Pavlos Androulakakis

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The purpose of this thesis is to examine the ability of evolutionary algorithms (EAs) to develop near optimal solutions to three different path planning control problems. First, we begin by examining the evolution of an open-loop controller for the turn-circle intercept problem. We then extend the evolutionary methodology to develop a solution to the closedloop Dubins Vehicle problem. Finally, we attempt to evolve a closed-loop solution to the turn constrained pursuit evasion problem. For each of the presented problems, a custom controller representation is used. The goal of using custom controller representations (as opposed to more standard techniques such as …

Leveraging 3d Models For Sar-Based Navigation In Gps-Denied Environments, Zachary A. Reid

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This thesis considers the use of synthetic aperture radar (SAR) to provide absolute platform position information in scenarios where GPS signals may be degraded, jammed, or spoofed. Two algorithms are presented, and both leverage known 3D ground structure in an area of interest, e.g. provided by LIDAR data, to provide georeferenced position information to airborne SAR platforms. The first approach is based on the wide-aperture layover properties of elevated reflectors, while the second approach is based on correlating backprojected imagery with digital elevation imagery. Both of these approaches constitute the system we have designated: SARNAV. Building on 3D backprojection, localization …

Microstructural Characterization Of LensTm Ti-6al-4v: Investigating The Effects Of Process Variables Across Multiple Deposit Geometries, Laura Christine Davidson

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Laser based additive manufacturing of Ti-6Al-4V components is under consideration for aerospace applications. The mechanical properties of the finished components depend on their microstructure. Process mapping compares process variables such as heat source power, heat source travel speed, material feed rate, part preheat temperature and feature geometry to process outcomes such as microstructure, melt pool geometry and residual stresses. In this work, the microstructure of two-dimensional pads, multilayer pads, thin walls, and structural components at the steady state location was observed. A method for measuring β grain widths that allows for the calculation of standard deviations, confidence intervals, and variances …

An Autonomous Intelligent Robotic Wheelchair To Assist People In Need: Standing-Up, Turning-Around And Sitting-Down, Iosif Papadakis Ktistakis

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The world’s ageing population has significantly increased over the last decades, which will result in one of the most significant transformations of the twenty-first century. As people age, they become more vulnerable to diseases and their health may need constant monitoring. At the same time, the number of people who have some kind of disability is also increasing. These people with disabilities may need daily assistance and monitoring of their health condition that is provided by specialists (health providers) at a high cost. A possible solution to the aforementioned problem comes from the assistive and intelligent robotics research area. The …

Interactive Visualization Of Search Results Of Large Document Sets, James D. Anderson

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When presented with many search results, finding information or patterns within the data poses a challenge. This thesis presents the design, implementation and evaluation of a visualization enabling users to browse through voluminous information and comprehend the data. Implemented with the JavaScript library Data Driven Documents (D3), the visualization represents the search as clusters of similar documents grouped into bubbles with the contents depicted as word-clouds. Highly interactive features such as touch gestures and intuitive menu actions allow for expeditious exploration of the search results. Other features include drag-and-drop functionality for articles among bubbles, merging nodes, and refining the search …

Switching Neural Network Systems For Nonlinear Tracking, Manoj Ghimire

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In this thesis, we consider the problem of tracking in complex nonlinear dynamical systems. While the Kalman filter is known to be the mean-squared error optimal tracker under linear dynamics and linear measurements, more sophisticated models and algorithms are required for complex dynamics. Here, we consider switching systems where the dynamical properties vary (''switch modes") over time. For example, the dynamics of a vehicle may switch as it transitions from interstate to urban conditions, human speech dynamics switch as speakers change, and stock market dynamics switch with discrete news events. In this work, we use mode-dependent neural networks to capture …

Overwhelming The Saa System Of Delivery Uavs By Drone Swarming, Barry Lynn Pfaff

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As the Internet continues to replace the brick-and-mortar store as the main place for purchasing goods, web-based companies are looking for ways to reduce the cost of delivering those goods. The use of Unmanned Aerial Vehicles, or UAVs, is one delivery method that is increasingly being used. These UAVs can be programmed with delivery routes and destinations and can complete the job while requiring limited intervention from human controllers. Sense and Avoidance (SAA) systems have recently been incorporated into these UAVs so that they can detect objects in their flight path, reroute the UAV accordingly and operate even more autonomously. …

Fully Transparent Computer Vision Framework For Ship Detection And Tracking In Satellite Imagery, Jason T. Gottweis

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Tracking of ships in satellite imagery is a challenging problem in remote sensing since it requires both object detection and object recognition. Most of the resources available only cover one of these problems and are often filled with machine learning techniques which are costly to train. Additionally, the techniques covered in these resources are often difficult to replicate or may be hard to combine with other solutions to get a full tracking algorithm. The proposed framework offers a transparent and efficient alternative to machine learning approaches and includes preprocessing, detection, and recognition needed for tracking. All components of the framework …

Augment The Multi-Modal Interaction Capabilities Of Hololens Through Networked Sensory Devices, Subhadra Tummalapally

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Augmented Reality (AR) places virtual contents along with real objects to enhance user perception in the physical environment. It is a technology that has shown great potential in many industries such as medicine, education and transportation. AR devices, such as Microsoft HoloLens, come with multi-modal interaction capabilities, such as voice, gesture and gaze, to support intuitive and reliable human-computer interactions. However, HoloLens gesture support is limited to simple gestures like tap, bloom and hold, it stops short to support meaningful interaction through full hand gesture and motion tracking, which may be critical in field operations of various industry practices in …

Wideband Doa And Parameter Estimation Of Chirp Sources Using Dcft And Compressive Sensing, Luay A. Al Irkhis

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Direction of Arrival (DoA) estimation of chirp sources has many applications in radar, sonar and medical imaging. This work considers DoA and parameter estimation of wide- band chirp sources by the use of Discrete Chirp Fourier Transform (DCFT), its Compres- sive Sensing formulation (CS-DCFT) and Distributed CS. DCFT is similar to traditional Discrete Fourier Transform (DFT) but with chirp ba- sis and two-dimensional search over chirp rate and chirp frequency. For chirp parame- ters estimation, the proposed Compressive Sensing (CS) formulation uses the parametric DCFT basis to achieve superior estimator performance in polynomial time using Orthog- onal Matching Pursuit (OMP) …

Garbage Disposal, Madison Popa, Tyler Miller, Mitchell Wheeler, Johnathon Klebe

Williams Honors College, Honors Research Projects

The purpose of this report is to outline a new design for a sink garbage disposal system. The goal of this design is to develop a garbage disposal that could be made for less money, which would turn into a cost savings for the consumer and would lead to an increase in the amount of garbage disposal systems being used throughout the world. This allows the garbage disposal system to be marketed to different parts of the world that currently can’t afford the systems available on the market.

The increased use of garbage disposals, help reduce the amount of organic …

Development Of Entubulation Strategies For Treating Central Nervous System Injuries, Ivy Brosch

Williams Honors College, Honors Research Projects

According to the McKnight Brain Institute, at least 10,000 people annually in the USA suffer from a central nervous system (CNS) injury. These injuries can cause serve disabilities including paralysis. Due to the complexity of the spinal cord, it is common that potential CNS treatments are first applied to an optic nerve crush (ONC) model in rats. Two proposed treatments were employed; one where nerve growth factor (NGF) was immobilized to a chitosan substrate to stimulate axonal regeneration, and the other using pentadecafluorooctanoyl chloride modified methacrylamide chitosan (MAC(Ali15)F) hydrogel to enhance local oxygenation. The two different treatments were formed into …

Evaluation Of Silane-Doped Epoxy Coatings For Resisting Aluminum Corrosion By Oxalic Acid, An A. Niger Metabolite, Alex Pica

Williams Honors College, Honors Research Projects

The goal of this study was to investigate whether silane-doped epoxy coatings are capable of preventing corrosion of aluminum alloy 2024-T3 by oxalic acid, one of the primary metabolites of the fungus Aspergillus Niger. Previous research suggested the success of these types of coatings at preventing AA 2024-T3 corrosion in saline solutions, and this study was meant to build on those findings by investigating the efficacy of the coating in an acidic environment.

Each coating was applied to an AA 2024-T3 coupon by dissolving the epoxy and varying amounts of 3-aminopropyltriethoxysilane in acetone and then dripping the solution onto …