Engineering Commons^™

An Fpga-Based Hardware Accelerator For The Digital Image Correlation Engine, Keaten Stokke

Graduate Theses and Dissertations

The work presented in this thesis was aimed at the development of a hardware accelerator for the Digital Image Correlation engine (DICe) and compare two methods of data access, USB and Ethernet. The original DICe software package was created by Sandia National Laboratories and is written in C++. The software runs on any typical workstation PC and performs image correlation on available frame data produced by a camera. When DICe is introduced to a high volume of frames, the correlation time is on the order of days. The time to process and analyze data with DICe becomes a concern when …

Stay-At-Home Motor Rehabilitation: Optimizing Spatiotemporal Learning On Low-Cost Capacitive Sensor Arrays, Reid Sutherland

Graduate Theses and Dissertations

Repeated, consistent, and precise gesture performance is a key part of recovery for stroke and other motor-impaired patients. Close professional supervision to these exercises is also essential to ensure proper neuromotor repair, which consumes a large amount of medical resources. Gesture recognition systems are emerging as stay-at-home solutions to this problem, but the best solutions are expensive, and the inexpensive solutions are not universal enough to tackle patient-to-patient variability. While many methods have been studied and implemented, the gesture recognition system designer does not have a strategy to effectively predict the right method to fit the needs of a patient. …

Investigations Of New Fault-Tolerant Methods For Multilevel Inverters, Haider Mhiesan

Graduate Theses and Dissertations

The demands of power electronics with high power capability have increased in the last decades. These needs have driven the expansion of existing power electronics topologies and developing new power electronics generations. Multilevel inverters (MLI) are one of the most promising power electronics circuits that have been implemented and commercialized in high-voltage direct current (HVDC), motor drives, and battery energy storage systems (BESS). The expanding uses of the MLI have lead to creation of new topologies for different applications. However, one of the disadvantages of using MLIs is their complexity. MLIs consist of a large number of switching devices, which …

Locating Emergency Shelters While Incorporating Spatial Factors, Justin Taylor

Graduate Theses and Dissertations

In the immediate response phase of a natural disaster, local governments and nonprofit agencies often establish shelters for affected populations. Decisions regarding at which locations to open shelters are made ad hoc based on available building inventory, and may result in high travel impedance to reach shelters and congestion. This thesis presents a shelter location optimization model based on the two-step floating catchment area (2SFCA) method. The 2SFCA method creates a shelter accessibility score for each areal unit (e.g., census block group) which represents the ability for persons in the unit to access shelter capacity with low travel impedance, relative …

Design Of Submicron Structured Guided-Mode-Resonance Near-Infrared Polarizer, Marzia Zaman

Graduate Theses and Dissertations

The objective of this research is to design a larger submicron linear polarizer in the near-infrared wavelength range with a wide bandwidth which can be fabricated using the conventional thin-film microfabrication technology to reduce cost. For this purpose, a gold (Au) wire-grid transmission-type transverse-magnetic (TM) polarizer and a silicon (Si) wire-grid reflection-type TM polarizer, were designed using the guided-mode-resonance filter. The Au wire-grid TM polarizer of 700nm grating width and 1200nm grating period has 95% transmittance at 2400nm, more than 1000nm resonance peak bandwidth, and an extinction ratio (ER) of around 300 with a moderated level of sidebands. The 700nm …

Design And Simulation Of Power Electronics Modules, Haonan Jia

Graduate Theses and Dissertations

Silicon carbide (SiC), a wide-bandgap semiconductor material, greatly improves the performance of power semiconductor devices. Its electrical characteristics have a positive impact on the size, efficiency, and weight of the power electronics systems. Parasitic circuit elements and thermal properties are critical to the power electronics module design. This thesis investigates the various aspects of layout design, electrical simulation, thermal simulation, and peripheral design of SiC power electronic modules. ANSYS simulator was used to design and simulate the power electronic modules. The parasitic circuit elements of the power module were obtained from the device parameters given in the datasheet of these …

Low Latency Anomaly Detection With Imperfect Models, Samrat Nath

Graduate Theses and Dissertations

The problem of anomaly detection deals with detecting abrupt changes/anomalies in the distribution of sequentially observed data in a stochastic system. This problem applies to many applications, such as signal processing, intrusion detection, quality control, medical diagnosis, etc. A low latency anomaly detection algorithm, which is based on the framework of quickest change detection (QCD), aims at minimizing the detection delay of anomalies in the sequentially observed data while ensuring satisfactory detection accuracy. Moreover, in many practical applications, complete knowledge of the post-change distribution model might not be available due to the unexpected nature of the change. Hence, the objective …

Study Of A Symmetrical Llc Dual-Active Bridge Resonant Converter Topology For Battery Storage Systems, John K. George

Graduate Theses and Dissertations

A symmetrical LLC resonant converter topology with a fixed-frequency quasi-triple phase-shift modulation method is proposed for battery-powered electric traction systems with extensions to other battery storage systems. Operation of the converter with these methods yields two unique transfer characteristics and is dependent on the switching frequency. The converter exhibits several desirable features: 1) load-independent buck-boost voltage conversion when operated at the low-impedance resonant frequency, allowing for dc-link voltage regulation, zero-voltage switching across a wide load range, and intrinsic load transient resilience; 2) power flow control when operated outside the low-impedance resonance for integrated battery charging; 3) and simple operational mode …

Peptoid And Antibody-Based Gfp Sensors, Solomon Isu

Graduate Theses and Dissertations

In this work, we have made and characterized a pair of immunobiosensors for detecting the green fluorescent protein (GFP) in an aqueous matrix. An anti-GFP antibody-based biosensor was assembled to detect GFP, while a novel peptoid (N-substituted oligomers of glycine designated as IOS-1) biosensor was also assembled for GFP detection. A quartz crystal microbalance (QCM) gold sensor was used as the supporting substrate for self-assembly of the immunobiosensors. Gravimetric measurements of the QCM gold sensor during immunobiosensor construction and operation were available in real-time using a QCM instrument. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Fluorescence microscopy were used …

A Power Constrained 433-Mhz Low Noise Amplifier, Pablo Alvarez Arellano

Graduate Theses and Dissertations

Within wireless communication systems, low noise amplifiers are critical for the performance of receivers. They are primarily responsible for providing enough gain while adding little noise to overcome the noise of the subsequent stages. The LNA presented here is part of a battery-powered transceiver meant to measure crop nutrient data and relay the information. Therefore, power consumption and area become import considerations. To design for a specific power level, a power-constrained noise optimization method is used. The method sizes the amplifying transistor for a fixed source impedance, power dissipation, technology, and operating frequency. The chosen topology is the cascode stage …

Built-In Self-Test (Bist) For Multi-Threshold Null Convention Logic (Mtncl) Circuits, Brett Sparkman

Graduate Theses and Dissertations

This dissertation proposes a Built-In Self-Test (BIST) hardware implementation for Multi-Threshold NULL Convention Logic (MTNCL) circuits. Two different methods are proposed: an area-optimized topology that requires minimal area overhead, and a test-performance-optimized topology that utilizes parallelism and internal hardware to reduce the overall test time through additional controllability points. Furthermore, an automated software flow is proposed to insert, simulate, and analyze an input MTNCL netlist to obtain a desired fault coverage, if possible, through iterative digital and fault simulations. The proposed automated flow is capable of producing both area-optimized and test-performance-optimized BIST circuits and scripts for digital and fault simulation …

A Novel Three-Level Isolated Ac-Dc Pfc Power Converter Topology With Reduced Number Of Switches, Obaid Aldosari

Graduate Theses and Dissertations

The three-level isolated AC-DC power factor corrected (PFC) converter provides safe and more efficient power conversion. In comparison with two-level, three-level PFC converter has the advantages of low total harmonic distortion, low device voltage rating, low di/dt, better output performance, high power factor, and low switching losses at higher switching frequencies. The high frequency transformer (HFT) grants galvanic isolation, steps up or down secondary voltage, and limits damage in case of a fault current.

The existing three-level converter based on solid-state transformer (SST) topologies convert ac power from the electrical grid to a dc load while maintaining at least the …

Area Efficient Device Optimization For Esd Protection In High Speed Interface Ics, Dan Thomas Jarard

Graduate Theses and Dissertations

Electrostatic discharge (ESD) protection is considered as a vital step in integrated circuit (IC) manufacturing process. IC chips are unable to overcome the effects of transient events without adequate discharge protection. Recent trend in the industry has seen the incorporation of system level ESD protection within the IC chip. Incorporating system level on-chip ESD protection often increases cost, degrades circuit performance and consumes layout area which could otherwise be used for improving the circuit performance. These design challenges could be easily overcome if the parasitic components in a circuit were used for ESD protection. Despite the various design challenges, on-chip …

Characterization Of Avidin And Case9 Single Protein Molecules By A Solid-State Nanopore Device, Haopeng Li

Graduate Theses and Dissertations

The shape and charge of a protein play significant roles in protein dynamics in the biological system of humans and animals. Characterizing and quantifying the shape and charge of a protein at the single-molecule level remains a challenge. Solid-state nanopores made of silicon nitride (SiNx) have emerged as novel platforms for biosensing such as diagnostics for single-molecule detection and DNA sequencing. SSN detection is based on measuring the variations in ionic conductance as charged biomolecules translocate through nanometer-sized channels driven by an external voltage applied across the membrane. In this paper, we observe the translocation of asymmetric cylindrical structure CRISPR-Cas9 …

Cybersecurity Methods For Grid-Connected Power Electronics, Stephen Joe Moquin

Graduate Theses and Dissertations

The present work shows a secure-by-design process, defense-in-depth method, and security techniques for a secure distributed energy resource. The distributed energy resource is a cybersecure, solar inverter and battery energy storage system prototype, collectively called the Cybersecure Power Router. Consideration is given to the use of the Smart Green Power Node for a foundation of the present work. Metrics for controller security are investigated to evaluate firmware security techniques. The prototype's ability to mitigate, respond to, and recover from firmware integrity degradation is examined. The prototype shows many working security techniques within the context of a grid-connected, distributed energy resource. …

Incorporating Geophysical Data In Slope Stability Modeling For Two Slopes In Arkansas, Vanessa Lebow

Graduate Theses and Dissertations

Slope failures in the United States alone cause millions of dollars in damage to infrastructure, threaten national monuments, create environmental hazards, and take an average of 25-50 lives a year. With the inevitable construction that occurs on slopes, it is imperative that the slopes be properly designed which requires a thorough understanding of slope grade, subsurface soil conditions, soil strength parameters, water table locations, and depth to bedrock across the entire site. The preferred method of data collection would be to use borings and other in-situ methods; however, sometimes due to cost constraints or site accessibility only a very limited …

Evaluation Of Concrete Deck Curing Regimens Using Capillary Pressure Sensing System, Samuel Spann

Graduate Theses and Dissertations

Early-age plastic shrinkage cracking is a common problem with the construction of concrete bridge decks due to the high surface area-to-volume ratio and exposure to potentially detrimental environmental effects. Curing regimens are utilized to mitigate cracking risk during the plastic stage of the concrete; the curing regimens evaluated for this study were wet burlap-polyethylene sheeting, two acrylic curing compounds, and one lithium compound. Capillary pressure in the water filled pores has been shown to correlate to the plastic shrinkage cracking risk of concrete. A new portable system has been developed to measure the capillary pressure that could potentially be used …

Truck Activity Pattern Classification Using Anonymous Mobile Sensor Data, Taslima Akter

Graduate Theses and Dissertations

To construct, operate, and maintain a transportation system that supports the efficient movement of freight, transportation agencies must understand economic drivers of freight flow. This is a challenge since freight movement data available to transportation agencies is typically void of commodity and industry information, factors that tie freight movements to underlying economic conditions. With recent advances in the resolution and availability of big data from Global Positioning Systems (GPS), it may be possible to fill this critical freight data gap. However, there is a need for methodological approaches to enable usage of this data for freight planning and operations.

To …

Study Of Internal Strains Developed In Concrete Decks At Early Ages In Steel Continuous Bridges, Fernando R. Benitez Ortiz

Graduate Theses and Dissertations

The Arkansas Department of Transportation (ARDOT) has identified bridge deck cracking shortly after concrete decks are placed and prior to applying traffic loads. Previous researchers have confirmed improper construction practices and design methods can lead to deck cracking. Currently, many contractors throughout Arkansas are using continuous deck pours. This construction approach may restrict the concrete slab from movement during early age shrinkage, causing tensile stresses to develop. The final stresses at the end of construction must be lower than the concrete tensile strength, if not cracking issues will develop. Eventually, these cracks may enlarge due to service load stresses and …

Cytotoxicity And Mutagenicity Of Disinfection Byproduct Mixtures Formulated Using Free Chlorine And Monochloramine, Yonas Ghebremedhin

Graduate Theses and Dissertations

Bioassays have been used extensively to assess various toxicity endpoints of drinking water disinfection byproducts (DBPs), but an emphasis on single compounds prevails. In this research, DBP mixtures were assessed using a cytotoxicity test with Chinese Hamster Ovary (CHO) cells and an Ames fluctuation test with Salmonella typhimurium TA-98 and TA-100 with and without S9 rat liver homogenate. Seven whole mixture DBP concentrates were formulated using reconstituted natural organic matter (NOM) extracts from the Upper Mississippi River using scaled disinfectant dosing protocols with free chlorine and monochloramine in the presence and absence of added bromide. DBPs were identified by gas …

Weigh-In-Motion Auto-Calibration Using Automatic Vehicle Identification, Fu Ren Zhang Zhang Durandal

Graduate Theses and Dissertations

Weigh-in-Motion (WIM) sensors are installed on mainline lanes at highway locations to record vehicle weights, axle spacing, vehicle class, travel speed, vehicle length, and traffic volume. These data elements support effective transportation planning, infrastructure design, and policy development. Therefore, it is important that WIM sensors supply accurate data. After initial installation and calibration, WIM systems may experience measurement drifts in weight and axle detection. Recalibration takes two general forms: (a) On-site calibration involving running trucks of known weight over WIM scales and (b) Auto-calibration methods involving comparisons to assumed reference weights. Auto-calibration can be more cost and time effective than …

Evaluation Of Fracture Principles In Asphalt Concrete Utilizing The Sc(B) Geometry, Airam Marlee Morales Vega

Graduate Theses and Dissertations

Since cracking is one of the principal distresses to be considered in asphalt concrete, multiple fracture tests and geometries have been used to quantify cracking resistance. One of the most popular geometries that have been used in fracture tests is the Semi-Circular bend (SC(B)). However, for this geometry, most of the fracture test methods use different parameters such as thickness, testing temperatures, and loading rates. Thus, the purpose of this research was first to evaluate fracture energy by performing a ruggedness test based on ASTM E1169. Then, to apply fracture mechanics concepts to evaluate three specimen thicknesses (25, 50, and …

Production And Purification Of Basic Fibroblast Growth Factor Fused To Two Collagen Binding Domains Expressed In E. Coli Bl21 Using Flask And Fed-Batch, Hazim Aljewari

Graduate Theses and Dissertations

Delivering effective and non-toxic doses of bioactive materials that can aid in activating tissue regeneration to wounded tissue has proven to be an enormous challenge. This study was designed to produce a potential therapeutic recombinant protein by fusing two collagen binding domains to basic fibroblast growth factors (bFGF) through a collagenase cleavage site linker, so it can release the bFGF in a wound site by the action of this enzyme. The novel fusion protein was expressed in Escherichia coli BL-21 (E. coli) using traditional flask shaker and fed-batch cultivation. Cell lysate was purified by FPLC using Immobilized metal affinity chromatography …

In Vivo Metabolic And Vascular Response To Hypoxia In Twist Knockdown Murine Breast Cancer, Brandon Sturgill

Graduate Theses and Dissertations

Twist transcription factor is often overexpressed in aggressive tumors. Although needed in early embryonic development for organogenesis, Twist is known to induce an epithelial to mesenchymal transition in cells. In cancer, epithelial to mesenchymal transitions can lead to increased motility and invasiveness. It has also been linked to metabolic reprogramming and increased metastatic risk. Furthermore, metabolic preferences can increase proliferation, enhance metastatic potential, and influence the site of metastasis. We hypothesize that Twist directly affects the metabolism of cancer cells. We expect to see in vivo what we have seen in vitro; Twist overexpression should promote a shift away from …

Optimized Production And Evaluation Of Cellulose Nanocrystals Derived From Pre-Extracted Kraft Pulp Of Different Wood Species, Gurshagan Kandhola

Graduate Theses and Dissertations

Production of nanocellulose from a variety of naturally abundant, locally available and industrially significant wood species provides an opportunity for diversifying the portfolio of traditional pulp and paper industries. The U.S. has a prolific forest products industry with a well-established infrastructure that could be utilized for optimized and customized production of cellulose nanomaterials. However, to achieve that, it is important to a) understand how biorefining strategies for complete fractionation of biomass affect the downstream processing of pulp into nanocellulose, b) maximize the yields of cellulose nanocrystals and nanofibers (CNCs and CNFs) from pretreated raw materials, and c) evaluate if the …

Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity, Ricardo Raphael Lopez Romo

Graduate Theses and Dissertations

Noble metal nanoparticles and two-dimensional (2D) transition metal dichalcogenide (TMD) crystals offer unique optical and electronic properties that include strong exciton binding, spin-orbital coupling, and localized surface plasmon resonance. Controlling these properties at high spatiotemporal resolution can support emerging optoelectronic coupling and enhanced optical features. Excitation dynamics of these optical properties on physicochemically bonded mono- and few-layer TMD crystals with metal nanocrystals and two overlapping spherical metal nanocrystals were examined by concurrently (i) DDA simulations and (ii) far-field optical transmission UV-vis spectroscopic measurements. Initially, a novel and scalable method to unsettle van der Waals bonds in bulk TMDs to prepare …

High Frequency Ltcc Based Planar Transformer, Adithya Venkatanarayanan

Graduate Theses and Dissertations

As we move towards high power and higher frequency related technology, conventional wire-wound magnetics have their own limitations which has led path to the development of planar based magnetic materials. Nowadays more planar magnetic technology has been employed because it is easier to fabricate them. The planar magnetic is a transformer or an inductor that replaces the wire-wound transformer or inductors which generally uses copper wires. One of the main reasons why we move to planar magnetic technology is its operation at higher frequency which provides higher power density. This study explains in detail about the design and fabrication of …

Design And Optimization Of A High Power Density Silicon Carbide Traction Inverter, Tyler Adamson

Graduate Theses and Dissertations

This project was initiated with the goal of demonstrating a 3-phase silicon carbide based 150-kW 25 kW/L DC-AC power conversion unit capable of operation with coolant temperatures up to 90°C. The project goals were met and exceeded by first analyzing the established inverter topologies to find which one would yield the highest power density while still meeting electrical performance needs in the 150-kW range. Following topology selection, the smallest silicon carbide power module that met the electrical requirements of the system was found through experimental testing and simulation. After a power module selection was finalized, a DC link capacitor bank …

Theoretical Investigations Of The Electronic, Magnetic, And Thermoelectric Properties Of Transition-Metal Based Compounds, Haleoot Edaan Raad

Graduate Theses and Dissertations

The electronic, magnetic, and thermoelectric properties of transition-metal based compounds were investigated by using the density functional theory and Boltzmann transport formalism. It was found that the Co-based Heusler compounds and InSe monochalcogenide are among the materials that may be used for future thermoelectric devices. Furthermore, the investigation showed that the quaternary Heusler compounds, such as, CoFeYGe, where Y is Ti or Cr, are half-metallic ferromagnetic materials with full electron spin polarization. The lattice thermal conductivity (κL) was found to decrease for these alloys as the temperature increases. The present investigation indicated that the phonon optical modes have a major …

Exploring Convergence Of Snake Skin-Inspired Texture Designs And Additive Manufacturing For Mechanical Traction, Catherine Sue Tiner

Graduate Theses and Dissertations

This research focuses on the understanding, development, and additive manufacture of a 3D printed snake skin-inspired texture pattern. The design functionalities of snake skin were determined through the study of the snake species Python Regius otherwise known as the ball python. Each scale of a snake has hierarchical texture with hexagonal macro-patterns aligned on the ventral surface of the skin with overriding anisotropic micro textured patterns such as denticulations and fibrils. Using a laser-powder bed fusion (L-PBF) process, 420 stainless steel samples were 3D printed which closely resemble the above described directional texture of natural snake skin. This printed surface …