Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Louisville

Electronic Theses and Dissertations

Theses/Dissertations

2019

Articles 1 - 30 of 45

Full-Text Articles in Engineering

Non-Invasive Detection And Assessment Of Coronary Stenosis From Blood Mean Residence Times., Javad Hashemi Dec 2019

Non-Invasive Detection And Assessment Of Coronary Stenosis From Blood Mean Residence Times., Javad Hashemi

Electronic Theses and Dissertations

Coronary artery stenosis is an abnormal narrowing of a coronary artery caused by an atherosclerotic lesion that reduces lumen space. Fractional flow reserve (FFR) is the gold standard method to determine the severity of coronary stenosis based on the determination of rest and hyperemic pressure fields, but requires an invasive medical procedure. Normal FFR is 1.0 and FFR RT, to account for varying volume and flow rate of individual segments. BloodRT was computed in 100 patients who had undergone the pressure-wire FFR procedure, and a threshold for BloodRT was determined to assess the physiological significance of a stenosis, …


Development And Characterization Of A Biopolymer Direct-Write Process For 3d Microvascular Structures Formation., Xiaoming Fan Dec 2019

Development And Characterization Of A Biopolymer Direct-Write Process For 3d Microvascular Structures Formation., Xiaoming Fan

Electronic Theses and Dissertations

Engineering of bulk tissues has been limited by the lack of nutrient and waste exchange in these tissues without an adjacent capillary network. To produce microvasculature, a scaffold must be produced that provides temporary mechanical support and stimulate endothelial cell adhesion, growth, and morphogenesis into a vessel. However, current well-established techniques for producing microvasculature, such as electrospinning, are limited since they lack both the precision to control fiber placement in three-dimensional space and the ability to create fiber networks with predefined diameters to replicate the physiological microvascular progression from arteriole to capillary to venule. Our group has developed a “Direct-write” …


Exploratory Learning Activities In The Physics Classroom: Contrasting Cases Versus A Rich Dataset., Campbell Rightmyer Bego Dec 2019

Exploratory Learning Activities In The Physics Classroom: Contrasting Cases Versus A Rich Dataset., Campbell Rightmyer Bego

Electronic Theses and Dissertations

In exploratory learning, students engage in an exploration activity on a new topic prior to instruction. This inversion of the traditional tell-then-practice order has been shown to benefit learning outcomes, especially conceptual knowledge and preparation for future learning, but not always. In three studies, the current work examines whether the type of exploration activity impacts learning mechanisms and outcomes, on the topic of gravitational field in undergraduate physics classrooms. Activities using either contrasting cases (CC) or a rich dataset (RD) are compared in two instructional orders, explore-first (EF) and instruct-first (IF). Learning outcomes measured procedural knowledge, conceptual knowledge, and performance …


Simulation And Optimization Of A Multi-Agent System On Physical Internet Enabled Interconnected Urban Logistics., Long Zheng Dec 2019

Simulation And Optimization Of A Multi-Agent System On Physical Internet Enabled Interconnected Urban Logistics., Long Zheng

Electronic Theses and Dissertations

An urban logistics system is composed of multiple agents, e.g., shippers, carriers, and distribution centers, etc., and multi-modal networks. The structure of Physical Internet (PI) transportation network is different from current logistics practices, and simulation can effectively model a series of PI-approach scenarios. In addition to the baseline model, three more scenarios are enacted based on different characteristics: shared trucks, shared hubs, and shared flows with other less-than-truckload shipments passing through the urban area. Five performance measures, i.e., truck distance per container, mean truck time per container, lead time, CO2 emissions, and transport mean fill rate, are included in …


Stabilization Of Bimodal Colloidal Systems Via Nanoparticle Haloing In Microgravity., Luke Hawtrey Dec 2019

Stabilization Of Bimodal Colloidal Systems Via Nanoparticle Haloing In Microgravity., Luke Hawtrey

Electronic Theses and Dissertations

Colloidal suspensions typically contain a multi-phase system of solid particles suspended in a liquid medium. Colloids are widely used in industrial applications such as inks, paints, motor oils, foods, cosmetics, and many more. Colloidal systems are typically formed by the interaction of the attractive van der Waals forces and one or more repulsive forces. These repulsive forces include electrostatic repulsion, steric hindrance, and nanoparticle haloing. Nanoparticle Haloing (NPH) is a phenomenon discovered in 2001 as a viable method to stabilize colloidal systems of uncharged silica microparticles using highly charged zirconia nanoparticles. For this thesis the effects of NPH were tested …


Aisle Design For Order Picking Operations With Unit-Load Replenishment., Dominic Ian Sleigh Dec 2019

Aisle Design For Order Picking Operations With Unit-Load Replenishment., Dominic Ian Sleigh

Electronic Theses and Dissertations

The warehouse design problem has been addressed in the last decade with fewer constraints than ever before. Between optimization for unit load and order picking warehouses, the former has had extensively more research performed. Unit load optimization efforts have promised labor savings of 20-22%. Of the existing research for order-picking warehouses, only small improvements of less than 4% have been claimed. We propose the design optimization for order-picking warehouses requires consideration for inherently incurred unit load operations from pallet inbound activities, as well as forward-pick area replenishment. We perform experiments comparing optimization of aisle design using order picking data with …


A Kinetic And Thermodynamic Model Of Ethylene Dichloride Pyrolysis., Travis J Czechorski Nov 2019

A Kinetic And Thermodynamic Model Of Ethylene Dichloride Pyrolysis., Travis J Czechorski

Electronic Theses and Dissertations

Ethylene dichloride (EDC) is a precursor for the production of vinyl chloride (VCM) which is subsequently polymerized to form polyvinyl chloride (PVC). To convert EDC to VCM, EDC undergoes a pyrolysis process in the absence of oxygen at temperatures exceeding 500C. However, process yields are limited by the uncontrolled production of side-products that can degrade the quality of PVC and poison the reactor. Thus, tight process controls and costly separations guided by heuristics and plant operator experience are used to optimize EDC pyrolysis. To improve the process, I have programed a kinetic model of EDC pyrolysis based upon estimations of …


Hardware Implementation Of Boost Power Factor Correction Converter., Shruti Motilal Deore Aug 2019

Hardware Implementation Of Boost Power Factor Correction Converter., Shruti Motilal Deore

Electronic Theses and Dissertations

Nowadays, there has been an increasing demand of unity power factor in electrical power sector. Due to the nonlinear nature of load equipment, switching devices, source voltage and current are out of phase with each other. Many power converters topologies are used for the power factor correction. The boost converter with controller is most common for power factor correction circuits. The controller objective is to maintain the output voltage regulation and input current tracking with source voltage. The voltage ripple present due to the ac component of the current tracking objective, hence instead of ignoring that ripple, it is used …


Cognitive Satellite Communications And Representation Learning For Streaming And Complex Graphs., Wenqi Liu Aug 2019

Cognitive Satellite Communications And Representation Learning For Streaming And Complex Graphs., Wenqi Liu

Electronic Theses and Dissertations

This dissertation includes two topics. The first topic studies a promising dynamic spectrum access algorithm (DSA) that improves the throughput of satellite communication (SATCOM) under the uncertainty. The other topic investigates distributed representation learning for streaming and complex networks. DSA allows a secondary user to access the spectrum that are not occupied by primary users. However, uncertainty in SATCOM causes more spectrum sensing errors. In this dissertation, the uncertainty has been addressed by formulating a DSA decision-making process as a Partially Observable Markov Decision Process (POMDP) model to optimally determine which channels to sense and access. Large-scale networks have attracted …


Triple-Junction Solar Cells : In Parallel., Levi C Mays Aug 2019

Triple-Junction Solar Cells : In Parallel., Levi C Mays

Electronic Theses and Dissertations

This paper looks into the current inefficiency of solar cells and attempts a few alternative solar cell structures in order to provide a more effective source of renewable energy. Currently, multi-junction solar cells are being developed to capture the sun’s light more efficiently. One of the ideas in this paper is to add a window to see if the addition of such a layer into a junction will increase the voltage while maintaining nearly the same current output. Central to this paper is the rearranging of the conducting layers of the multi-junction cell so that the junctions can be connected …


Fluid Flow Analysis Of Diluted Evaporating American Whiskey Droplets., Martin J. Brown Vi Aug 2019

Fluid Flow Analysis Of Diluted Evaporating American Whiskey Droplets., Martin J. Brown Vi

Electronic Theses and Dissertations

The recent discovery of the unique structures, whiskey webs, formed when the evaporation of diluted American whiskey, has raised many questions as to the nature of the structures. Their formation process follows as such: (1) dilution of the whiskey to form nanoaggregates, (2) formation of a monolayer at the air-liquid interface, (3) chaotic ethanol evaporation caused monolayer collapse (via dynamic pressure), (4) bulk fluid evaporation caused monolayer collapse (via reduction of surface area), where the web-like structures reside on the surface, and finally, (5) web-like structures deposit on the substrate. The webs imaged via SEM had a striking resemblance to …


Design And Predicting Performance Of Carbon Nanotube Reinforced Cementitious Materials : Mechanical Properties And Dispersion Characteristics., Mahyar Ramezani Aug 2019

Design And Predicting Performance Of Carbon Nanotube Reinforced Cementitious Materials : Mechanical Properties And Dispersion Characteristics., Mahyar Ramezani

Electronic Theses and Dissertations

Recently, Carbon Nanotubes (CNTs) are drawing considerable attention of researchers for reinforcing cementitious materials due to their excellent mechanical properties and high aspect ratio (length-to-diameter ratio). However, CNTs might not disperse well within the cement matrix, resulting in little improvement or even degradation of concrete properties. The uncertainty in producing the consistent results in different studies might be attributed to multiple interactions between the experimental variables affecting the nanotube dispersion and the final properties of CNT-cement nanocomposites. Therefore, this research mainly focused on proposing equations that can reliably capture these interactions in order to correlate CNT dispersion with the mechanical …


Optical Direct Detection Of Thermal Vibrations Of Ultralow Stiffness Micro-Nano Structures., Sri Sukanta Chowdhury Aug 2019

Optical Direct Detection Of Thermal Vibrations Of Ultralow Stiffness Micro-Nano Structures., Sri Sukanta Chowdhury

Electronic Theses and Dissertations

A direct detection optical vibrometer is constructed around an 850 nm laser and a quadrant photodetector (QPD). The limit of detection is 0.2 fW which corresponds to a minimum amplitude of 0.1 Å. The vibrometer is used to measure the thermal vibration spectra of low stiffness micromechanical structures have nanometer features. One structure measured is a cantilevered 30 μm diameter glass fiber. Vibration amplitudes as low as 1.1 Å are measured. The thermal vibration spectra show fundamental resonances at 80-250 Hz and a signal to noise ratio (SNR) of 23-55 dB. Young’s modulus of glass in the cantilevers, estimated from …


Adaptive Physical Human-Robot Interaction (Phri) With A Robotic Nursing Assistant., Sumit Kumar Das Aug 2019

Adaptive Physical Human-Robot Interaction (Phri) With A Robotic Nursing Assistant., Sumit Kumar Das

Electronic Theses and Dissertations

Recently, more and more robots are being investigated for future applications in health-care. For instance, in nursing assistance, seamless Human-Robot Interaction (HRI) is very important for sharing workspaces and workloads between medical staff, patients, and robots. In this thesis we introduce a novel robot - the Adaptive Robot Nursing Assistant (ARNA) and its underlying components. ARNA has been designed specifically to assist nurses with day-to-day tasks such as walking patients, pick-and-place item retrieval, and routine patient health monitoring. An adaptive HRI in nursing applications creates a positive user experience, increase nurse productivity and task completion rates, as reported by experimentation …


Formally Designing And Implementing Cyber Security Mechanisms In Industrial Control Networks., Mehdi Sabraoui Aug 2019

Formally Designing And Implementing Cyber Security Mechanisms In Industrial Control Networks., Mehdi Sabraoui

Electronic Theses and Dissertations

This dissertation describes progress in the state-of-the-art for developing and deploying formally verified cyber security devices in industrial control networks. It begins by detailing the unique struggles that are faced in industrial control networks and why concepts and technologies developed for securing traditional networks might not be appropriate. It uses these unique struggles and examples of contemporary cyber-attacks targeting control systems to argue that progress in securing control systems is best met with formal verification of systems, their specifications, and their security properties. This dissertation then presents a development process and identifies two technologies, TLA+ and seL4, that can be …


An Explainable Recommender System Based On Semantically-Aware Matrix Factorization., Mohammed Sanad Alshammari Aug 2019

An Explainable Recommender System Based On Semantically-Aware Matrix Factorization., Mohammed Sanad Alshammari

Electronic Theses and Dissertations

Collaborative Filtering techniques provide the ability to handle big and sparse data to predict the ratings for unseen items with high accuracy. Matrix factorization is an accurate collaborative filtering method used to predict user preferences. However, it is a black box system that recommends items to users without being able to explain why. This is due to the type of information these systems use to build models. Although rich in information, user ratings do not adequately satisfy the need for explanation in certain domains. White box systems, in contrast, can, by nature, easily generate explanations. However, their predictions are less …


All Season Heat Pipe System., Adrienne Marie Parsons Aug 2019

All Season Heat Pipe System., Adrienne Marie Parsons

Electronic Theses and Dissertations

Our energy choices impact the earth’s natural systems and climate. As this becomes increasingly important, the need for decreasing our energy usage is essential. Conventional passive solar systems can significantly reduce the heating load. Similarly, passive ambient energy systems, such as ventilation and sky radiation, can reduce cooling loads. However, the integration of passive heating and cooling systems in the same building and the benefits of actively controlling these otherwise passive systems to maximize annual energy savings has largely been unexplored. This study first evaluates the building cooling capacity of sky radiation, which was previously identified to have the greatest …


Improving Flow-Induced Hemolysis Prediction Models., Mohammad Mohaghegh Faghih Aug 2019

Improving Flow-Induced Hemolysis Prediction Models., Mohammad Mohaghegh Faghih

Electronic Theses and Dissertations

Partial or complete failure of red blood cell membrane, also known as hemolysis, is a persistent issue with almost all blood contacting devices. Many experimental and theoretical contributions over the last few decades have increased insight into the mechanisms of mechanical hemolysis in both laminar and turbulent flow regimes, with the ultimate goal of developing a comprehensive, mechanistic and universal hemolysis prediction model. My research is broadly divided into two sections: theoretical/analytical/Computational Fluid Dynamics (CFD) analyses and experimental tests. The first part of my research revolved entirely around analyzing the simplest and most popular hemolysis model, commonly called as the …


Purification Of Biomass Hydrolyzates For The Promotion Of Xylose Diester Formation, Laura Fernandez Aug 2019

Purification Of Biomass Hydrolyzates For The Promotion Of Xylose Diester Formation, Laura Fernandez

Electronic Theses and Dissertations

The application of a novel xylose isolation procedure using phenyl boronic acid esterification has been limited to the hydrolyzates of low extractive biomasses like hardwoods and agricultural resides. Hydrolyzates with lower sugar and higher extractive concentrations, like softwoods, have not yielded xylose, or even xylose diester (XDE), the first intermediate product in the new process, under the same conditions. This research applied evaporation concentration, adsorbent separation and membrane filtration to these lower performing biomass hydrolyzates to maximize the yield of the XDE formation step of the new xylose extraction process. Lab-scale tests of these techniques were applied to pine hydrolyzate …


Solarpede: An Untethered Micro Robot Powered By Light., Jordan Fredrick Klotz Aug 2019

Solarpede: An Untethered Micro Robot Powered By Light., Jordan Fredrick Klotz

Electronic Theses and Dissertations

Micro-Robotics looks to implement robotics principles at a small scale and has gained popularity in recent decades as a gateway to new research areas such as micro-factory applications. The SolarPede is a second-generation, cm-scale micro-crawler designed for such micro factory applications which is equipped with a legged locomotion system and an electronic backpack. The SolarPede is an evolution of its predecessors and features power and signal conditioning capabilities, gait pattern generation, and Bluetooth connectivity. The components which make up SolarPede have been full validated and tested, and its systems have been realized in the form of a body made from …


Simulation Of A Continuum Tumor Model Using Distributed Computing., Dylan A Goodin Jul 2019

Simulation Of A Continuum Tumor Model Using Distributed Computing., Dylan A Goodin

Electronic Theses and Dissertations

Mathematical modeling aims to provide a theoretical framework for understanding tissue dynamics and for establishing treatment response for diseased tissues, such as tumors. Previously published continuum models have successfully represented idealized two-dimensional and three-dimensional tissue for short periods of time. A recently published continuum model of cancer increases model complexity and describes three-dimensional tissue that, due to the required complexity of the geometric multigrid solver, can only be feasibly applied to millimeter-scale simulations. Furthermore, the computational cost for such models has hindered their application in the laboratory and in the clinic. With computational demands greatly outpacing current openMP-based approaches on …


Feasibility Study Of Intelligent Lvad Control For Optimal Heart Failure Therapy., John A. Karlen Iii Jul 2019

Feasibility Study Of Intelligent Lvad Control For Optimal Heart Failure Therapy., John A. Karlen Iii

Electronic Theses and Dissertations

Background: Left ventricular assist devices (LVAD) are operated at constant speeds (rpm), consequently, pump flow is passively determined by the pressure difference between the LV and aorta. Since the diastolic pressure gradient (~70 mmHg) is much larger than the systolic gradient (~10 mmHg), the majority of pump flow occurs during systole. This limitation results in sub-optimal LV volume unloading, LV washing, and diminished vascular pulsatility that may be associated with increased risk for clinically-significant adverse events, including stroke, bleeding, arteriovenous malformations, and aortic insufficiency. To address these clinical adverse events, an intelligent control strategy using pump speed modulation was developed …


Nanowire Based Adsorbents/Catalysts For Co2 Capture And Utilization., Apolo Nambo May 2019

Nanowire Based Adsorbents/Catalysts For Co2 Capture And Utilization., Apolo Nambo

Electronic Theses and Dissertations

Even today, the major energy source is fossil fuels, which release CO2, a greenhouse gas that contributes to global warming. CO2 capture, storage (CCS) and/or utilization (CCU) technologies are two routes to mitigate this problem. Sorbents are being investigated in either temperature swing or pressure swing absorption approaches for carbon capture from flue gases. Solid sorbent based technology is a promising one but suffers from slow kinetics, low capacity and need for high temperatures. Thus, new sorbent materials that can have good CO2 sorption capacity, recyclability are sought. Similarly, one of the utilization approaches for CO …


Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides., Babajide Patrick Ajayi May 2019

Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides., Babajide Patrick Ajayi

Electronic Theses and Dissertations

Clean energy production and storage are two of the most significant challenges in the 21st century currently limited by the discovery and development of new and advanced materials. Complex oxides and alloys made using earth-abundant elements will play a crucial role in technology development moving forward, however, current preparation techniques are limited by their inability to produce complex oxides and alloys with precise composition control at fast timescales. A concept was proposed to produce mixed metal oxides with composition control through the oxidation of liquid precursors via plasma oxidation. It was hypothesized that the oxidation process can be completed …


A Two-Stage Approach To Ridesharing Assignment And Auction In A Crowdsourcing Collaborative Transportation Platform., Peiyu Luo May 2019

A Two-Stage Approach To Ridesharing Assignment And Auction In A Crowdsourcing Collaborative Transportation Platform., Peiyu Luo

Electronic Theses and Dissertations

Collaborative transportation platforms have emerged as an innovative way for firms and individuals to meet their transportation needs through using services from external profit-seeking drivers. A number of collaborative transportation platforms (such as Uber, Lyft, and MyDHL) arise to facilitate such delivery requests in recent years. A particular collaborative transportation platform usually provides a two sided marketplace with one set of members (service seekers or passengers) posting tasks, and the another set of members (service providers or drivers) accepting on these tasks and providing services. As the collaborative transportation platform attracts more service seekers and providers, the number of open …


Maximizing Space Utilization In Unit-Load Warehouses., Luis Felipe Cardona Olarte May 2019

Maximizing Space Utilization In Unit-Load Warehouses., Luis Felipe Cardona Olarte

Electronic Theses and Dissertations

In a unit-load warehouse, products are stored and retrieved in pallet quantities. Examples include retail distribution centers (DC), third-party DCs, and transshipment hubs in freight transportation. Expenses related to space are a significant component of the operational cost of unit-load warehouses; therefore, maximizing space utilization is important. Moreover, the continuing revolution of retail e-commerce is changing the role and design of modern distribution centers (Boysen et al., 2018). An important trend with serious implications for design is the desire of many distributors to locate DCs in or near metropolitan areas in order to support same-day service or better (Thuermer, 2018). …


Plasma-Assisted Liquid Phase Epitaxy Of Gallium Nitride Using Molten Gallium., Daniel Felipe Jaramillo-Cabanzo May 2019

Plasma-Assisted Liquid Phase Epitaxy Of Gallium Nitride Using Molten Gallium., Daniel Felipe Jaramillo-Cabanzo

Electronic Theses and Dissertations

Next generation semiconductor materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) are rapidly replacing Silicon (Si) for high power and high frequency applications due to Si’s inherent limitations. Despite the advantages of GaN over SiC, adoption of GaN has been hindered due to the lack of a cost-effective bulk production technique. Thus, the inability to precure native substrates requires GaN-based architectures to be heteroepitaxially synthesized on non-native substrates, such as sapphire and even SiC. This research seeks to develop a cost effective and scalable method to produce low defect, bulk GaN encouraging the adoption of GaN based devices …


Lithium Molybdate-Sulfur Battery., Ruchira Ravinath Dharmasena May 2019

Lithium Molybdate-Sulfur Battery., Ruchira Ravinath Dharmasena

Electronic Theses and Dissertations

Rechargeable energy storage systems play a vital role in today’s automobile industry with the emergence of electric vehicles (EVs). In order to meet the targets set by the department of energy (DOE), there is an immediate need of new battery chemistries with higher energy density than the current Li- ion technology. Lithium–sulfur (Li–S) batteries have attracted enormous attention in the energy-storage, due to their high specific energy density of 2600 Wh kg-1 and operational voltage of 2.0 V. Despite the promising electrochemical characteristics, Li-S batteries suffer from serious technical challenges such as dissolution of polysulfides Li2Sx …


Evaluating The Water Quantity And Quality Performances Of Underground Gravel Filter Basins., Jihad A. Hallany May 2019

Evaluating The Water Quantity And Quality Performances Of Underground Gravel Filter Basins., Jihad A. Hallany

Electronic Theses and Dissertations

Underground gravel filter basins (UGF basins) are subsurface structures that are used for detention, filtration, and infiltration of stormwater runoff in urbanized areas. The application of these structures is recommended in highly developed urban areas, where land is not available or it is too expensive for surface-level green infrastructures such as stormwater ponds, bio-retention, and infiltration trenches. Objectives of this study are to assess and analyze the effectiveness of two (2) UGF basins in reducing the stormwater runoff peak flow, and to assess water quality parameters in a high-density residential area. The experimental site is located at Red Mile Village, …


Clustering Heterogeneous Autism Spectrum Disorder Data., Mariem Boujelbene May 2019

Clustering Heterogeneous Autism Spectrum Disorder Data., Mariem Boujelbene

Electronic Theses and Dissertations

Autism spectrum disorder (ASD) is a developmental disorder that affects communication and behavior. Several studies have been conducted in the past years to develop a better understanding of the disease and therefore a better diagnosis and a better treatment by analyzing diverse data sets consisting of behavioral surveys and tests, phenotype description, and brain imagery. However, data analysis is challenged by the diversity, complexity and heterogeneity of patient cases and by the need for integrating diverse data sets to reach a better understanding of ASD. The aim of our study is to mine homogeneous groups of patients from a heterogeneous …