Engineering Commons^™

Deployable Mechanisms And Applications For Minimally Invasive Surgery, Jacob L. Sheffield

Theses and Dissertations

This thesis explores techniques to utilize deployable, developable, and compliant mechanism design principles while investigating applications for minimally invasive surgery. This work also examines contemporary outreach strategies to broaden awareness and expand dissemination avenues of engineering research. The outcomes of this research aim to (i) equip product designers with machine design tools, (ii) deliver background and designs to mitigate surgical frustration and procedure complications associated with obstructed laparoscope lenses during laparoscopic surgery, and (iii) provide engineering researchers with new tools to extend the impact of their research. Part one of this work (Chapter 2) introduces methods for embedding linear-motion mechanisms …

Electroplating And Machining Of Silicon Carbide Wafers, Madeline Beth Thompson

Theses and Dissertations

Silicon carbide has many properties that make it a promising and desirable material for diverse applications. One such application for silicon carbide wafers is as a transparent cryogenic probe card. This thesis briefly describes the design of a probe card based on a silicon carbide wafer substrate. It includes a description of electroplating fundamentals and demonstrates the feasibility of electroplating copper onto a wafer for the formation of bond pads between the substrate and external PCB ring. The process for electroplating copper with good adhesion and quality based on metal alloy formation, current control, and materials selection is outlined. Results …

Lumbar Skin Strain Fields In The Context Of Skin Adhered Wearables, Andrew Kent Gibbons

Theses and Dissertations

A comprehensive background is herein presented for lumbar skin strain and its effect on skin adhered wearable (SAW) products. A background of the development of computational models of the interaction of skin and novel SAWs being researched is also presented. These include products involving the use of high deflection strain gauges to measure skin strain during functional movements (FMs) as a method to address the complicated phenotyping of the etiological causes of low back pain (LBP). The background concludes with the mathematical calculation of the principal skin strain magnitudes and orientations using retroreflective marker coordinate data in a motion capture …

Indirect Tensile Strength Of Clayey Soils Treated With Cement Or Lime, Melissa Adams Cowley

Theses and Dissertations

The objectives of this research were to evaluate the sensitivity of indirect tensile strength (ITS) test results to stabilizer type, stabilizer concentration, and curing time for multiple clayey soils with varying plasticity indices (PIs), identify cases in which an ITS of 30 psi can be obtained, and create a general linear model that predicts ITS. The scope of work included laboratory testing of three clayey soils sampled from Monticello, Utah; Bloomington, Indiana; and San Antonio, Texas. Each soil was tested using two stabilizers, cement or lime, at three concentrations, and two replicate samples were prepared for each combination. ITS testing …

3rd Party Ip Encryption From Netlist To Bitstream For Xilinx 7-Series Fpgas, Daniel Hutchings

Theses and Dissertations

IP vendors need to keep the internal designs of their IP secret from the IP user for security or commercial reasons. The CAD tools provided by FPGA vendors have some built-in functionality to encrypt the IP. However, the IP is consequently decrypted by the CAD tools in order to run the IP through the design flow. An IP user can use APIs provided by the CAD tools to recreate the IP in an unencrypted state. An IP user could also easily learn the internals of a protected IP with the advent of new open-source bitstream to netlist tools. The user …

Investigating Bismuth As A Surrogate For Plutonium Electrorefining, Greg Chipman

Theses and Dissertations

Conducting research experiments on plutonium electrorefining is difficult due to the significant hazards and regulations associated with nuclear materials. Finding a surrogate for plutonium electrorefining studies would enable more fundamental research to be conducted. Potential surrogates were identified by determining the physical properties required to conduct electrorefining using a molten metal and molten salt in CaCl2 at 1123 K. More potential surrogates were identified by changing the matrix salt to be a LiCl-KCl-CaCl2 eutectic salt with electrorefining conducted at 673-773 K. Ce-CeCl3, In-InCl3, Zn-ZnCl2, Sn-SnCl2, and Bi-BiCl¬3 were investigated as potential plutonium electrorefining surrogates. Ce electrorefining in molten CaCl2 resulted …

Using Dynamic Task Allocation To Evaluate Driving Performance, Situation Awareness, And Cognitive Load At Different Levels Of Partial Autonomy, Viraj R. Patel

Theses and Dissertations

The state of the art of autonomous vehicles requires operators to remain vigilant while performing secondary tasks. The goal of this research was to investigate how dynamically allocated secondary tasks affected driving performance, cognitive load, and situation awareness. Secondary tasks were presented at rates based on the autonomy level present and whether the autonomous system was engaged. A rapid secondary task rate was also presented for two short periods regardless of whether autonomy was engaged. There was a three-minute familiarization phase followed by a data collection phase where participants responded to secondary tasks while preventing the vehicle from colliding into …

Vertical Federated Learning Using Autoencoders With Applications In Electrocardiograms, Wesley William Chorney

Theses and Dissertations

Federated learning is a framework in machine learning that allows for training a model while maintaining data privacy. Moreover, it allows clients with their own data to collaborate in order to build a stronger, shared model. Federated learning is of particular interest to healthcare data, since it is of the utmost importance to respect patient privacy while still building useful diagnostic tools. However, healthcare data can be complicated — data format might differ across providers, leading to unexpected inputs and incompatibility between different providers. For example, electrocardiograms might differ in sampling rate or number of leads used, meaning that a …

Development Of Preservative-Treated Cross-Laminated Timber And Lignin-Reinforced Polyurethane-Adhesive For Glued Laminated Timber, Samuel Oluwafemi Ayanleye

Theses and Dissertations

Interest in the use of mass timber in building and construction is growing worldwide, this is due to the structural integrity and reduced environmental footprint of timber-based structures. Concerns associated with the biological and environmental degradation of mass timber necessitate the development of adequate protection strategies to ensure the durability of these products. Preservative treatment is a proven technique that increases the durability and performance of wood in-service and can also be applied to large-sized timber panels such as cross-laminated timber (CLT). Therefore, this study focused on investigating the feasibility of treating prefabricated 3- and 5-layer CLT panels with Copper-azole …

Ide-Based Learning Analytics For Assessing Introductory Programming Skill, Phyllis J. Beck

Theses and Dissertations

Providing a sufficient level of personalized feedback on students' current level of strategic knowledge within the context of the natural programming environment through IDE-based learning analytics would transform learning outcomes for introductory programming students. However, providing sufficient insight into the programming process was previously inaccessible due to the need for more complex and scalable data collection methods and metrics with a wider variety for understanding programming metacognition and the full programming process.

This research developed a custom-built web-based IDE and event compression system to investigate two of the five components of a five-dimensional model of cognition for programming skill estimation …

Assessing And Predicting The Students’ Systems Thinking Preference: Multi-Criteria Decision Making And Machine Learning, Siham Tazzit

Theses and Dissertations

The 21st century is marked by a technological revolution that features digital implementation and high interconnectivity between systems across different domains, such as transportation, agriculture, education, and health. Although these technological changes resulted in modern systems capable of easing individuals’ lives, these systems are increasingly complex, and that increased complexity is only expected to continue. The increased system complexity is due to the rapid exchange of information between subsystems, which creates high interconnectivity and interdependence between the subsystems and their elements. Workforce skill sets, as a result, must be modified appropriately to ensure the systems’ success. Systems Thinking is an …

The Effects Of Mechanical Strain On Vascular Calcification And The Canonical Wnt Pathway, Hannah E. Douglas

Theses and Dissertations

Cardiovascular disease is a significant health crisis, representing 32% of deaths worldwide in 2019. Vascular calcification (VC), a major contributor to cardiovascular disease, is a regulated biomineralization process whose exact mechanisms are unknown. Additionally, vascular smooth muscle cells (VSMCs) significantly contribute to VC by undergoing a phenotypic switch and differentiating into osteoblast-like cells. When factors like hypertension cause disturbed laminar flow in the body’s vasculature, the mechanical stress promotes the phenotypic switch and calcification of VSMCs via mechanotransduction. VC is also induced by the Wnt pathway, which is activated via mineral imbalance and mechanical stimulation. However, the exact mechanisms behind …

Effects Of High School Engineering Course Availability And Participation On Engineering School Recruitment, Discipline Selection, Persistence Attitudes, And Self-Efficacy, Kristin S. Sandberg

Theses and Dissertations

The need for engineers in the workforce continues to grow. Filling this need requires recruiting future engineers to colleges and universities and retaining them through to degree completion. However, this is easier said than done. Universities are tasked with attempting to keep up with the demand for new engineers and companies are searching for new engineers to recruit. One avenue that has been established in the attempt to reach students for engineering is offering engineering or STEM classes in K-12 schools.

This dissertation looked at engineering classes offered at the high school level. These courses were analyzed for relationships with …

Elucidating Self-Assembly Of Semiconducting Polymers In The Presence Of A Low Molecular Weight Gelator, Madhubhashini Lakdusinghe

Theses and Dissertations

Semiconducting polymers with a conjugated backbone are important for energy storage, conversion, and biomedical field applications. The self-assembly process of these polymers in solutions depends on the polymer concentration and quality of the solvent. The electrical properties of thin films obtained from the solution phase depend on the self-assembled process. Thin films of conjugated polymer gels with percolating networks of self-assembled structures display improved electrical conductivities. In this dissertation, we studied the impact of the secondary gel matrix formed by a low molecular weight gelator, on the self-assembly of conjugated polymers, the preservation of assembled structures in dried gel films …

Effect Of Environmental And Geometrical Factors On Microstructure, Desiccation Cracking, And Carbon Dioxide Flux In Clays, Charles Clayton Goodman

Theses and Dissertations

Studying the effects of extreme conditions, such as high temperatures and low humidity, on soil properties is important to various disciplines, including geotechnical engineering, soil science, waste management, crop management, and ceramics. The goal of this research is to investigate the effect of environmental and geometrical factors on microstructure, desiccation cracking, and CO₂ flux in clays. The objectives of this research are threefold. (1) Understand the effects of temperature on the microstructure of clay soils; (2) develop a standardized procedure for studying desiccation cracking in a laboratory setting with reliable and repeatable results; and (3) develop an environmental chamber …

Gas Permeability Of 3d Stitched Composites For Cryogenic Applications, Shuvam Saha

Theses and Dissertations

This research aims to investigate the influence of 3D through-thickness stitching on the gas permeability and transverse microcracking of cryogenically cycled carbon/epoxy composites. 3D through-thickness stitching can be used to improve the interlaminar properties of polymer matrix composites (PMCs) and produce lightweight, unitized structures for cryogenic storage tanks. To fully utilize stitched composite structures for these applications, their inherent gas permeability challenges must be understood. Therefore, in this study, the stitched composites' damage evolution and gas permeability was experimentally characterized under a) pure thermal stress, b) thermal and uniaxial mechanical stress, and c) thermal and biaxial mechanical stress. Helium gas …

Multi-Objective Design Optimization Of Two Configurations Of Ventricular Shunts For Hydrocephalus, Will Kirkpatrick

Theses and Dissertations

Hydrocephalus is developed when the flow of cerebrospinal fluid is obstructed in the ventricles and a pressure build-up is generated within the brain. Ventricular shunts are used to remove excess fluid from the brain, but these shunts have a common problem of failure due to the shunt being obstructed by the build-up of astrocytes. To address this, two sets of 27 designs of ventricular shunts were identified and analyzed with parameters that could potentially reduce obstruction risks. The performance of these designs was examined using fluid simulations on these two sets of 27 designs. One set explored close-tipped shunt designs, …

Comparing Current Consistency And Electrical Resistance Of Wearable Photovoltaic Cells Pre- And Post-Laundering And Pre- And Post-Corrosion Resistance Testing Conditions., Amit Talukder

Theses and Dissertations

Photovoltaic(PV) technology is promising due to its natural availability among energy harvesting technologies. There is a growing need for sustainable power sources that can function without being connected to a power source or needing regular battery replacements. Wearable PV cells are gaining popularity in different applications. However, most companies produce wearable PVs for terrestrial applications. Research on wearable PV applications for the marine environment remains limited because these cells suffer from several issues. This research compares commercially sourced wearable PV cells' maximum current consistency and electrical resistance for two testing conditions. The researcher followed standardized methods for these two laundering …

Nanoscale Modeling Of Membrane Systems Under Mechanical Deformation In Traumatic Brain Injury Using Molecular Dynamics, Anh Thi Ngoc Vo

Theses and Dissertations

Neuronal membrane disruption and mechanoporation are nanoscale damage mechanisms that critically affect brain cell viability during traumatic brain injury (TBI). These nanoscale cellular impairments are elusive in experiments and necessitate in silico approaches such as molecular dynamics (MD) simulations. Implementing MD, this research aims to investigate the effects of different key factors related to membrane deformation and damage, including force field resolutions, lipid compositions, and loading conditions.

To examine the impact of force field resolution, MD deformation simulations were conducted on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) lipid bilayer membranes, using all-atom (AA), united-atom (UA), and coarse-grained Martini (CG-M) force fields. The mechanical responses …

Non-Destructive Evaluation Of White Striping And Microbial Spoilage Of Broiler Breast Meat Using Structured-Illumination Reflectance Imaging, Ebenezer O. Olaniyi

Theses and Dissertations

Manual inspection is a prevailing practice for quality assessment of poultry meat, but it is labor-intensive, tedious, and subjective. This thesis aims to assess the efficacy of an emerging structured illumination reflectance imaging (SIRI) technique with machine learning approaches for assessing WS and microbial spoilage in broiler breast meat. Broiler breast meat samples were imaged by an in house-assembled SIRI platform under sinusoidal illumination. In first experiment, handcrafted texture features were extracted from direct component (DC, corresponding to conventional uniform illumination) and amplitude component (AC, unique to the use of sinusoidal illumination) images retrieved from raw SIRI pattern images build …

Designing Bioinspired Materials With Tunable Structures And Properties From Natural And Synthetic Polymers, Anandavalli Varadarajan

Theses and Dissertations

Biological systems are composed of complex materials which are responsible for performing various functions, such as providing structural support, mobility, functional adaptation to the environment, damage repair, and self-healing. These complex materials display excellent mechanical properties and can rapidly adapt to external stimuli. Thus, nature inspires in terms of source materials, functions, and designs to develop new-generation structural and functional materials. Polymers (natural or synthetic) are excellent sources of developing materials to mimic the functions of soft segments in biological systems. This dissertation focuses on synthesizing and characterizing two different materials with tunable structures and properties: complexes from natural polysaccharides …

Heat And Mass Transfer Modeling Of High-Temperature Moving-Bed Thermochemical Reactors, David Korba

Theses and Dissertations

With the global deployment of renewable energy generation at record rates, clean energy is steadily becoming competitive with its fossil-fuel counterparts. However, further expansion is limited by the inherent intermittency of renewable energy sources (solar, wind, wave, etc.), which typically do not match with daily and seasonal variations of global (and local) energy demand. Thermochemical energy storage (TCES) has demonstrated strong potential in being a technological pathway to provide on-demand process heat and handle the intrinsic variations in renewable energy generation and energy demand. TCES works on the premise of excess renewable heat driving an endothermic reduction reaction, in which …

The Cosolvent And Association Effect On Polymer Behaviors, Xiangyu Zhang

Theses and Dissertations

The blending or mixing is extensively utilized in diverse processes of polymers to bring about advantageous properties, but the behavior becomes intriguing when associations are involved and multi-solvents are used. Explanations based on chemistry-specific arguments are less than satisfactory in abstracting essential features, and lack the general applicability across various systems. So, this work focuses on capturing the physical force governing the phenomenon of interest by using a generic model. Highly non-trivial behaviors of polymers are often observed in multi-solvent solutions. It is known that polymers swell and dissolve in good solvents, while they tend to collapse and aggregate in …

Tuning The Metal/Acid Functionalities In Hzsm-5 For Efficient Dehydroaromatization, Genwei Chen

Theses and Dissertations

The increasing production of natural gas liquids attracts both academia and industry to develop on-purpose techniques converting those light alkanes to value-added chemicals. Dehydroaromatization is an alternative path for light alkane conversion to produce aromatics but still lacks active and stable catalysts. This work aims at the development of efficient dehydroaromatization catalysts by tuning the metal/acid bifunctionality of the Pt/HZSM-5 catalyst. Additionally, through co-processing light alkane with ammonia during the dehydroaromatization process, this study also proposes a new reaction system that could directly link the C-N bond for nitrile synthesis.

The results suggested that the activity, selectivity, and stability of …

Physical Layer Security With Unmanned Aerial Vehicles For Advanced Wireless Networks, Aly Sabri Abdalla

Theses and Dissertations

Unmanned aerial vehicles (UAVs) are emerging as enablers for supporting many applications and services, such as precision agriculture, search and rescue, temporary network deployment, coverage extension, and security. UAVs are being considered for integration into emerging wireless networks as aerial users, aerial relays (ARs), or aerial base stations (ABSs). This dissertation proposes employing UAVs to contribute to physical layer techniques that enhance the security performance of advanced wireless networks and services in terms of availability, resilience, and confidentiality. The focus is on securing terrestrial cellular communications against eavesdropping with a cellular-connected UAV that is dispatched as an AR or ABS. …

Direct Measurement Of The 114cd(N, Gamma)115cd Cross Section In The 1 Ev To 300 Kev Energy Range, Kofi Tutu Addo Assumin-Gyimah

Theses and Dissertations

The large thermal cross section of cadmium makes it ideal for many practical applications where screening of thermal neutrons is desired. For example, in non-destructive assay techniques, or for astrophysical studies of the s-process. All such applications require precise knowledge of the neutron-capture cross section on cadmium. Although there are some data on neutron-capture cross sections particularly at thermal energies and at energies relevant for astrophysics, there is very little data at most other energies. Further, the evaluated cross sections from the ENDF and JENDL databases disagree at high energies. Therefore, there is a critical need for precise knowledge of …

Resource Optimization Of Edge Servers Dealing With Priority-Based Workloads By Utilizing Service Level Objective-Aware Virtual Rebalancing, Amna Shahid

Theses and Dissertations

IoT enables profitable communication between sensor/actuator devices and the cloud. Slow network causing Edge data to lack Cloud analytics hinders real-time analytics adoption. VRebalance solves priority-based workload performance for stream processing at the Edge. BO is used in VRebalance to prioritize workloads and find optimal resource configurations for efficient resource management. Apache Storm platform was used with RIoTBench IoT benchmark tool for real-time stream processing. Tools were used to evaluate VRebalance. Study shows VRebalance is more effective than traditional methods, meeting SLO targets despite system changes. VRebalance decreased SLO violation rates by almost 30% for static priority-based workloads and 52.2% …

A Comparison Of Ground Reaction Forces And Muscle Activity Of The Tsunami Bar® Against A Rigid Barbell During Back Squat Phases, John Carver Middleton

Theses and Dissertations

An Institutional Review Board (IRB)-approved study was conducted to investigate the effects of the Tsunami Bar® (TB), a flexible barbell, on ground reaction force (GRF) production and muscle activity in the quadricep, hamstring, and gluteal muscle groups during phases of the squat exercise and compare the effects to the effects to using a rigid barbell (RB). A two-by-two repeated measures Analysis of Variance (ANOVA) test was used to compare the results. Descriptive statistics showed significantly higher GRFs for the TB during the unweighting phase, significant differences in GRFs between speeds for each phase, significantly higher forces on average with the …

Ruggedness Test Of A New Standardized Test Method For Abrasion Resistance Of E-Textiles, Erin Parker

Theses and Dissertations

Standard test methods provide product developers with information regarding materials' suitability for different purposes. Typically, current standards are suitable for determining the mechanical properties of new materials. However, in the case of electronic textiles (E-Textiles) and wearable technology (wearables), adding conductive components with added functionality makes utilizing textile standards difficult, and these standards will not provide information on mechanical and electrical properties of conductive elements. New standards for E-Textile and wearables testing are needed to ensure product developers can obtain the information necessary to make informed decisions about new products. Standards organizations such as the American Society for Testing and …

Re(Engineering) Student Success: Constructing Knowledge On Students’ Experiences In Engineering Education Programs To Encourage Holistic Student Success, Shaylin Williams

Theses and Dissertations

If a group of engineering deans were asked whether students at their institutions were successful and why, what information might they immediately or subconsciously use to measure or gauge the engineering students’ success? If only academic performance outcomes like GPA, individual course grades, or graduation rate race to their minds, then their rationale aligns with the majority of researchers. My research seeks to shift the mindset that frames engineering student success mainly within the boundaries of academic performance measures. By measuring students’ perceived autonomy, competence, social integration and relatedness within their programs, and aspirations after graduation, one can more accurately …