Engineering Commons^™

Composite-Based Additive Manufacturing Applications In The Polymer Injection Molding Cycle, Cody Bivens

Masters Theses

“The experimental method utilized in this research was the application of composite-based additive manufacturing (CBAM) mold plates in the injection molding process. The mold plates comprised carbon fibers and polyether ether ketone (PEEK) matrix. Modifications were made to the mold plates post manufacturing in order to properly adapt to the rest of the injection molding die. A custom cooling system was engineered and integrated into the injection molding machine for the CBAM mold plates. The polymer processed in the injection molding cycle for this study was Lustran 348 acrylonitrile butadiene styrene (ABS). The result of the trials conducted in this …

Fiber Reinforced Polymer Bar Investigation: Long-Term In-Situ Durability And Bond Strength Assessment In Conventional And Sustainable Concrete, Ali Fadhil Al-Khafaji

Doctoral Dissertations

"Corrosion of steel reinforcement and carbon dioxide emissions are two major global problems. Different methods, techniques, and materials have been implemented to mitigate these problems. Glass fiber-reinforced polymer (GFRP) bar presents itself as a solid alternative to replace conventional steel reinforcement owing to its fantastic features in resisting corrosion. Its demand is progressively increasing. Cement-based concrete, on the other hand, is not eco-friendly due to the excessive amount of carbon dioxide (CO₂) emissions yielded from its cement production. One of the alternatives used to mitigate the use of cement in concrete is fly ash. Fly ash is considered …

Analysis Of Turbulence Model Uncertainty For Canonical Flow Problems Including Shock Wave Boundary Layer Interaction Simulations, Aaron James Erb

Doctoral Dissertations

"The purpose of this research is to present results of an uncertainty and sensitivity analysis study of commonly used turbulence models in Reynolds-Averaged Navier-Stokes (RANS) codes due to the epistemic uncertainty in closure coefficients for a set of turbulence model validation cases that represent the structure of several canonical flow problems. The study focuses on the analysis of a 2D zero pressure gradient flat plate, a 2D wall mounted hump, and an axisymmetric shock wave boundary layer interaction, all of which are well documented on the NASA Langley Research Center Turbulence Modeling Resource website. The Spalart-Allmaras (SA), the Wilcox (2006) …

Theoretical Study Of Magnetic Particles In A Shear Flow Subjected To A Uniform Magnetic Field, Christopher A. Sobecki

Doctoral Dissertations

"Magnetic manipulation of non-spherical magnetic microparticles is important for applications in shape-based and magnetic-based separations such as waste management, disease diagnostics, drug delivery, and mining. Manipulations of magnetic microparticles also include chain formation to assemble compositions for electronics, drug loading designs, and magnetorheological fluids for smart armor, hydraulic brakes, and dampers. In microfluidic devices, separation-formation-effectiveness depends on the shape of the channel, the shear rate, and the magnetic field strength and direction.

Particle separation and chain formation involved highly complex and computational expense-demanding studies in microfluidic devices, magnetic fields, and particle- particle/wall interactions. This research took complex experimental studies and …

Studies On Tornado-Structure Interactions And Guidance On Design Tornadic Wind Loading, Zhi Li

Doctoral Dissertations

“Tornadoes are violent natural hazards that could caused significant property loss and fatalities. Statistical data indicates that most fatalities during tornado incidents were caused by the building failure under tornadoes. For example, in the 2011 Joplin Tornado, 161 people were killed, and 84 percent of the fatalities were related to the failure of buildings. In addition, most of the significant, tornado-induced property loss and fatalities are relevant to the tornadoes passing through the densely populated regions. Besides buildings, bridges were also severely damaged or destroyed by tornadoes in the United States. To reduce the tornado-induced loss, it is imperative to …

Effects Of Hydrological And Climatic Variables On Cyanobacterial Blooms In Four Large Shallow Lakes Fed By The Yangtze River, Jian Huang, Qiujin Xu, Xixi Wang, Hao Ji, Edward J. Quigley, Mohamadali Sharbatmaleki, Simeng Li, Beidou Xi, Biao Sun, Caole Li

Civil & Environmental Engineering Faculty Publications

Shallow lakes, one of the most widespread water bodies in the world, are easily shifted to a new trophic state due to external interferences. Shifting hydrologic conditions and climate change can cause cyanobacterial harmful algal blooms (CyanoHABs) in shallow lakes, which pose serious threats to ecological integrity and human health. This study analyzed the effects of hydrologic and meteorological variables on cyanobacterial blooms in Yangtze-connected lakes (Lake Dongting and Poyang) and isolated lakes (Lake Chao and Tai). The results show that (i) chlorophyll-a (Chl-a) concentration tends to decrease exponentially with increasing relative lake level fluctuations (RLLF) and precipitation, but to …

Bias And Fairness Of Evasion Attacks In Image Perturbation, Sichong Qin

All Master's Theses

When talking about protecting privacy of personal images, adversarial attack methods play key roles. These methods are created to protect against the unauthorized usage of personal images. Such methods protect personal privacy by adding some amount of perturbations, otherwise known as "noise", to input images to enhance privacy protection. Fawkes in Clean Attack method is one adversarial machine learning approach aimed at protecting personal privacy against abuse of personal images by unauthorized AI systems. In leveraging the Fawkes in Evasion Attack method and through running additional experiments against the Fawkes system, we were able to prove that the effectiveness of …

Visualization For Solving Non-Image Problems And Saliency Mapping, Divya Chandrika Kalla

All Master's Theses

High-dimensional data play an important role in knowledge discovery and data science. Integration of visualization, visual analytics, machine learning (ML), and data mining (DM) are the key aspects of data science research for high-dimensional data. This thesis is to explore the efficiency of a new algorithm to convert non-images data into raster images by visualizing data using heatmap in the collocated paired coordinates (CPC). These images are called the CPC-R images and the algorithm that produces them is called the CPC-R algorithm. Powerful deep learning methods open an opportunity to solve non-image ML/DM problems by transforming non-image ML problems into …

Hygrothermal Ageing Behavior And Mechanism Of Carbon Nanofibers Modified Flax Fiber-Reinforced Epoxy Laminates, Yanlei Wang, Wanxin Zhu, Baolin Wan, Ziping Meng, Baoguo Han

Civil and Environmental Engineering Faculty Research and Publications

This study investigated the effects of carbon nanofibers (CNFs) content on hygrothermal ageing behaviors and mechanisms of flax fiber-reinforced epoxy (FFRE) laminates. CNFs/FFRE laminates containing 0.25–2.0 wt% CNFs were fabricated and immersed in distilled water for 180 days. Water absorption and tensile as well as thermodynamic properties were investigated. The research results showed that CNFs played a significant role in the improvement of hygrothermal properties of FFRE laminates. The water uptake of CNFs/FFRE laminates was significantly decreased because CNFs improved water barrier properties of the laminates. The improvements of tensile and thermodynamic properties of CNFs/FFRE laminates were attributed to the …

The Internet-Of-Buildings (Iob) - Digital Twin Convergence Of Wearable And Iot Data With Gis/Bim, Clayton Miller, Mahmoud Abdelrahman, Adrian Chong, Filip Biljecki, Matias Quintana, Mario Frei, Michael Chew, Daniel Wong

Research Collection College of Integrative Studies

nternet-of-Things (IoT) devices in buildings and wearable technologies for occupants are quickly becoming widespread. These technologies provide copious amounts of high-quality temporal data pertaining to indoor and outdoor environmental quality, comfort, and energy consumption. However, a barrier to their use in many applications is the lack of spatial context in the built environment. Adding Building Information Models (BIM) and Geographic Information Systems (GIS) to these temporal sources unleashes potential. We call this data convergence the Internet-of-Buildings or IoB. In this paper, a digital twin case study of data intersection from various systems is outlined. Initial insights are discussed for an …

Above And Beyond: Ethics And Responsibility In Civil Engineering, Shannon Chance, Rob Lawlor, Inês Direito Direito, John Mitchell

Articles

This exploratory study investigates how nine London-based civil engineers have enacted ‘global responsibility’ and how their efforts involve ethics and professionalism. The study assesses moral philosophies related to ethics, as well as professional engineering bodies’ visions, accreditation standards, and requirements for continuing professional development. Regarding ethics, the study questions where the line falls between what an engineer ‘must do’ and what ‘would be good to do’. Although the term ethics did not spring to mind when participants were asked about making decisions related to global responsibility, participants’ concern for protecting the environment and making life better for people did, nonetheless, …

Feature Fusion Of Raman Chemical Imaging And Digital Histopathology Using Machine Learning For Prostate Cancer Detection, Trevor Doherty, Susan Mckeever, Nebras Al-Attar, Tiarnán Murphy, Claudia Aura, Arman Rahman, Amanda O'Neill,, Stephen P. Finn, Elaine Kay, William M. Gallagher, William G. Watson, Aoife Gowen, Patrick Jackman

Articles

The diagnosis of prostate cancer is challenging due to the heterogeneity of its presentations, leading to the over diagnosis and treatment of non-clinically important disease. Accurate diagnosis can directly benefit a patient’s quality of life and prognosis. Towards addressing this issue, we present a learning model for the automatic identification of prostate cancer. While many prostate cancer studies have adopted Raman spectroscopy approaches, none have utilised the combination of Raman Chemical Imaging (RCI) and other imaging modalities. This study uses multimodal images formed from stained Digital Histopathology (DP) and unstained RCI. The approach was developed and tested on a set …

Event-Driven Servers Using Asynchronous, Non-Blocking Network I/O: Performance Evaluation Of Kqueue And Epoll, Lorcan Leonard

Dissertations

This research project evaluates the performance of kqueue and epoll in the context of event-driven servers. The evaluation is done through benchmarking and tracing which are used to measure throughput and execution time respectively. The experiment is repeated for both a virtualised and native server environment. The results from the experiment are statistically analysed and compared. These results show significant differences between kqueue and epoll, and a profound impact of virtualisation as a variable.

A Comparison Of Instructional Efficiency Models In Third Level Education, Murali Rajendran

Dissertations

This study investigates the validity and sensitivity of a novel model of instructional efficiency: the parabolic model. The novel model is compared against state-of-the-art models present in instructional design today; Likelihood model, Deviational model and Multidimensional model. This models is based on the assumption that optimal mental workload and high performance leads to high efficiency, while other models assume that low mental workload and high performance leads to high efficiency. The investigation makes use of two instructional design conditions: a direct instructions approach to learning and its extension with a collaborative activity. A control group received the former instructional design …

A New Mmc Topology Which Decreases The Sub Module Voltage Fluctuations At Lower Switching Frequencies And Improves Converter Efficiency, Shahab Sajedi

Doctoral

Modular Multi-level inverters (MMCs) are becoming more common because of their suitability for applications in smart grids and multi-terminal HVDC transmission networks. The comparative study between the two classic topologies of MMC (AC side cascaded and DC side cascaded topologies) indicates some disadvantages which can affect their performance. The sub module voltage ripple and switching losses are one of the main issues and the reason for the appearance of the circulating current is sub module capacitor voltage ripple. Hence, the sub module capacitor needs to be large enough to constrain the voltage ripple when operating at lower switching frequencies. However, …

A Two-Level Information Modelling Translation Methodology And Framework To Achieve Semantic Interoperability In Constrained Geoobservational Sensor Systems, Paul Stacey

Doctoral

As geographical observational data capture, storage and sharing technologies such as in situ remote monitoring systems and spatial data infrastructures evolve, the vision of a Digital Earth, first articulated by Al Gore in 1998 is getting ever closer. However, there are still many challenges and open research questions. For example, data quality, provenance and heterogeneity remain an issue due to the complexity of geo-spatial data and information representation.

Observational data are often inadequately semantically enriched by geo-observational information systems or spatial data infrastructures and so they often do not fully capture the true meaning of the associated datasets. Furthermore, data …

Computational Modeling Of Climate Attributes And Condition Deterioration Of Concrete Highway Pavements, Salma Sultana

Electronic Theses and Dissertations

An efficient and safe road network secures the nation’s economy and prosperity by providing public mobility and freight transport. Maintenance and rehabilitation of the road network cost billions of dollars annually. Road and highway infrastructures performance in any country is impacted by load repetitions and it is further compromised by climate attributes and extreme weather events. Damages to roads and bridges are among the infrastructure failures that have occurred during these extreme events. If maintenance and rehabilitation are not done promptly, the damages to the road caused by heavy traffic and extreme climate may lead to life-threatening conditions for road …

Analytical Assessment Of Project Complexity: A Guide To Managing Projects Through Reduction Of Complexity, Christopher Vanarsdale

Dissertations, Master's Theses and Master's Reports

This research discusses the characteristics that make projects difficult to manage. Project inefficiencies and failures can be attributed to the structure of a system. Developing a measurement for complexity based on the number and nature of interactions in the system can allow project complexity to be reduced while still meeting project objectives. Previous research has identified characteristics or markers of complex systems but does not address how to measure or how to reduce a system’s complexity.

The objective of this dissertation is to develop a metric for complexity that assists project and emergency managers in reducing project complexity either by …

Transient Maneuvers And Pressure Analysis On An Automotive Torque Converter, Abigail A. Hempy

Dissertations, Master's Theses and Master's Reports

This work involves an investigation of internal fluid behavior of an automotive torque converter in a front-wheel drive automatic 6-speed transmission. The fluid behavior is identified through 29 pressure transducers instrumented throughout the torus, acquired through IR Telemetrics multiplexed channels, and analyzed with custom MATLAB code. The main vehicle operating conditions studied in this research are back drive scenarios or low motoring torques. Findings showed speed and torque limits for open converter coast down conditions as well as pressure field behavior with negative input torque.

Development Of The Carbon Nanotube Thermoacoustic Loudspeaker, Troy Bouman

Dissertations, Master's Theses and Master's Reports

Traditional speakers make sound by attaching a coil to a cone and moving that coil back and forth in a magnetic field (aka moving coil loudspeakers). The physics behind how to generate sound via this velocity boundary condition has largely been unchanged for over a hundred years. Interestingly, around the time moving coil loudspeakers were first investigated the idea of using heat to generate sound was also known. These thermoacoustic speakers heat and cool a thin material at acoustic frequencies to generate the pressure wave (i.e. they use a thermal boundary condition). Unfortunately, when the thermoacoustic principle was initially discovered …

Multi-Level Analysis Of Atomic Layer Deposition Barrier Coatings On Additively Manufactured Plastics For High Vacuum Applications, Nupur Bihari

Dissertations, Master's Theses and Master's Reports

While hardware innovations in micro/nano electronics and photonics are heavily patented, the rise of the open-source movement has significantly shifted focus to the importance of obtaining low-cost, functional and easily modifiable research equipment. This thesis provides a foundation of open source development of equipment to aid in the micro/nano electronics and photonics fields.

First, the massive acceptance of the open source Arduino microcontroller has aided in the development of control systems with a wide variety of uses. Here it is used for the development of an open-source dual axis gimbal system. This system is used to characterize optoelectronic properties of …

Active Gravity Offloading System With Infrared Tracking For Rover Testing, Travis Wavrunek

Dissertations, Master's Theses and Master's Reports

Gravity offloading is a tool used to test how different gravitational forces will impact the mobility of rovers bound for Lunar or Martian expeditions. Previous approaches have been successful in simulating partial gravity environments, and this report details how the Infrared- Gravity offload (IRGO) system, developed for the Planetary Surface Technology Development Laboratory (PSTDL) and lunar simulant sandbox, has a similar aim. Through a series of iterations, IRGO has been developed to actively track an infrared beacon and follow a rover within the test chamber to eliminate inertial and friction forces along two horizonal axes. A portion of a rover’s …

Design And Testing Of An Open Source Vacuum Oven For Research, Community Recycling, And Additive Manufacturing, Benjamin R. Hubbard

Dissertations, Master's Theses and Master's Reports

To aid the continuing growth of open source tools in the research community, this thesis presents two broadly useful instruments which can be built and operated for a fraction of the cost of equivalent or inferior commercial products. The first device is a digitally-replicable scale, which provides a single framework for making measurements on the order of milligrams all the way up to tens of kilograms by supporting multiple types of load cells. The second device is a vacuum oven, which is validated using the first. The open source vacuum oven facilitates the dehydration of materials at low temperature, providing …

Commissioning And Testing Of A New Dusty Thermal Vacuum Chamber, Ben Wiegand

Dissertations, Master's Theses and Master's Reports

The Dusty Thermal Vacuum Chamber (DTVAC) is a new facility purchased by the Planetary Surface Technology Development Lab (PSTDL) that will be used to test the Technology Readiness Level (TRL) of extraplanetary devices and systems. With the use of vacuum pumps and simulated regolith, the DTVAC can create extraplanetary environments such as those found on the Moon and Mars. This report details the actions that were taken to prepare the DTVAC for TRL testing, including the development of a Data Acquisition Center (DAC) and test fixtures, along with the findings of baseline tests that were performed to understand the behavior …

Towards Systems On Cloth: The Design, Manufacturing, And Validation Of Open-Source Embroidered Resistors, Somerset Schrock

Dissertations, Master's Theses and Master's Reports

This thesis is focused on advancing embroidered wearable electronics and textile electronics by creating open-source flexible resistors. Advancements in textile electronics could usher a new generation of smart devices that are entirely flexible. Current systems on cloth primarily use rigid components, which limits the flexibility and comfort of using the fabric devices. To advance this field, I propose a novel method of creating flexible electrical resistors with embroidery. To realize this technology, I created an open-source tool to create embroidery files for machine fabrication. This thesis details the methods and tools created for resistor fabrication. The resistors were tested to …

Multiscale Investigation Of Dropwise Condensation On A Smooth Hydrophilic Surface, Shahab Bayani Ahangar

Dissertations, Master's Theses and Master's Reports

The objective of this work is to identify the fundamental mechanism of dropwise condensation on a smooth solid surface by probing the solid-vapor interface during phase-change to evaluate the existence and structure of the thin film and the initial nucleus that develop during condensation. In this work, an automated Surface Plasmon Resonance imaging (SPRi) instrument with the ability to perform imaging in intensity modulation and angular modulation is developed. The SPRi instrument is used to probe (in three dimensions) the adsorbed film that forms on the substrate during dropwise condensation. SPRi with a lateral resolution of ~ 4-10 μm, thickness …

Marangoni Propulsion Of Active Particles, Saeed Jafari Kang

Dissertations, Master's Theses and Master's Reports

We study the surfing motion of active particles located at a flat liquid-gas interface. The particles create and maintain a surface tension gradient by asymmetrically discharging a surface tension-reducing agent. We employ theory and numerical simulation to investigate the Marangoni propulsion of these active surfers. First, we use the reciprocal theorem to establish a relationship between the propulsion speed and the release of the active chemical. This theoretical relation is utilized to examine the effect of wall confinement and geometry on the Marangoni-driven motion of active particle when the inertial effects are negligible and when the transports of the released …

The Effects Of Molybdenum, Chromium, And Niobium On Gray Iron For Brake Rotor Applications, Matthew Hasbrouck

Dissertations, Master's Theses and Master's Reports

Brake rotor composition and microstructure must be optimized for thermal and mechanical performance to avoid thermal-mechanical cracking, excessive wear, and to reduce noise. Niobium is an element that increases the strength and wear resistance of gray iron; however, the interaction of niobium with other common alloying elements (chromium and molybdenum) is not well understood. Thirteen gray cast iron alloys were produced with varying levels of carbon equivalent (CE), Cr, Mo, and Nb. Bars with four different diameters (8, 14, 22, and 30 mm) were cast from each alloy and microstructural and physical properties such as graphite flake morphology, pearlite spacing, …

Development Of A Method To Model An Enclosed, Coaxial Carbon Nanotube Speaker With Experimental Validation, Suraj Prabhu

Dissertations, Master's Theses and Master's Reports

Carbon nanotube (CNT) speakers operate on heat as compared to conventional loudspeakers that operate on vibration. CNT speakers are extremely lightweight, stretchable, flexible, and have high operating temperatures. Due to these advantages, CNT speakers are being considered as a viable replacement option for conventional loudspeakers. One such application is automotive exhaust noise control. The goal of this research is to design an enclosed, coaxial CNT speaker and to develop a modeling method to model this speaker using COMSOL Multiphysics.

As part of this research, an enclosed, coaxial CNT speaker was designed and manufactured for automotive exhaust noise control. The first …

Multi-Dimensional Modeling For Environmental Impact Assessment At Intersections Of The Food-Energy-Water Nexus, Jessica Daignault

Dissertations, Master's Theses and Master's Reports

This dissertation uses multi-dimensional modeling for environmental impact assessment at intersections of the Food-Energy-Water (FEW) Nexus, including life cycle assessment (LCA) modeling for quantification of environmental impacts due to household FEW consumption, a linear regression framework for quantification of water-use impacts of marginal electricity generation, and a multi-objective optimization model to assess monetization of water withdrawals for electricity generation and impacts to water stress due to electricity dispatch schemes. Chapter 2 of this dissertation summarizes the development of an LCA model that quantifies the direct and indirect environmental impacts of household FEW consumption. The model is executed through a novel …