Engineering Commons^™

Optical And Thermal Characterization Of Vertically Conducting Β-Ga₂O₃ Diodes Grown On 4h-Sic Substrates For Short-Wavelength (<254 Nm) Detection, Muhammad Hassan Tahir

Theses and Dissertations

The advancement of compact, thermally stable, and efficient devices for deepultraviolet (DUV) detection below 254 nm is critical for solar-blind sensing, radiation monitoring, and high-power electronics. This thesis presents the growth, fabrication, and detailed optical and thermal characterization of vertically conducting β-gallium oxide (βGa₂O₃) Schottky barrier diodes (SBDs) grown on n-type 4H-Silicon Carbide (4H-SiC) substrates using metal-organic chemical vapor deposition (MOCVD).

β-Ga₂O₃ is an ultra-wide bandgap (UWBG) semiconductor (~4.8 eV) with intrinsic DUV transparency and high breakdown electric field, making it an ideal candidate for short-wavelength photodetection. However, its low thermal conductivity limits its vertical device performance. To overcome this, …

Effect Of Growth Conditions On The Performance Of Vertically Conducting Beta-Ga2o3 Diodes On 4h-Sic Substrate By Mocvd, Nifat Jahan Nipa

Theses and Dissertations

This thesis highlights the critical influence of doping strategies, specifically co-delta doping with silicon (Si) and indium (In), on improving the structural quality and device performance of β-Ga₂O₃-based Schottky barrier diodes (SBDs). To achieve better thermal management, β-Ga₂O₃ thin film was grown on bulk 4H-SiC substrates using the Metal-Organic Chemical Vapor Deposition (MOCVD) technique, renowned for its precise control over composition, thickness and doping profile. The ultra-wide bandgap (UWBG), high critical breakdown field and low turn-on resistance of β-Ga₂O₃ make it a strong candidate for next-generation power electronics and short-wavelength detection in extreme environments. However, the presence of structural defects …

Characterizing The Relationships Between Cranial Geometry, Brain Morphometry, And Brain Mechanical Properties Using Mr Imaging And Elastography, Jessica Restivo

Theses and Dissertations

Traumatic brain injury (TBI) is a global health concern, with over 69 million cases annually. TBI risk depends on subject-specific neuroanatomical variation, yet research often only considers generic finite element (FE) models, based on the geometry and material composition of a 50th percentile male head. Although highly accurate, subject-specific models require expensive magnetic resonance (MR) imaging, elastography, and time-consuming computational resources. There is a need to create subject-specific TBI models that account for subject-specific variations, without neuroimaging. This study aims to create mathematical models to predict brain morphometry (dimensions, volume) [Objective 1] and mechanical properties (shear stiffness, damping ratio, octahedral …

Addressing Key Challenges In Mhz Power Converters, Aqarib Hussain

Theses and Dissertations

Power electronics are essential in applications such as aerospace, electric vehicles, and electric ships where compact, efficient, and high power-density converters are increasingly demanded. This push toward miniaturization has led to converter designs operating at switching frequencies in the megahertz (MHz) range. Higher-frequency operation enables significant reductions in passive component sizes—particularly transformers and inductors—thereby facilitating dense packaging. However, these benefits come with new challenges, including increased thermal stress, complex semiconductor behavior, higher-frequency magnetic design constraints, and elevated electromagnetic interference (EMI).

This research addresses several key challenges in MHz converter design. The first part involves the development of a 1-MHz, 1-kW …

Informing Cold Spray Via High Strain Rate Particle Impacts Captured Using Ultra-High-Speed Videography, Elias Timmons

Theses and Dissertations

The primary objective of this research is to provide insight into high strain rate deformation behavior of particles in cold spray-like impacts for the purposes of material vetting and optimization of spray parameters for deposition quality and efficiency. A light gas gun and ultra-high-speed videography techniques were engineered, built, and used for millimeter particle impact experiments and adapted to launch micron scale particles at controlled velocities and particle/substrate temperatures representative of cold spray conditions. Analytical techniques employed for understanding impact mechanics focused on characterization of impact behavior and presence of features related to cold spray particle bonding. This research demonstrates …

Simulations Of Single Metallic Particle Impacts Onto Polymeric Substrates For Insights Into Cold Spray Adhesion At Composite Material Interfaces, Saidur Rahman Shoaib

Theses and Dissertations

Metallization of polymer-based composites finds applications in a variety of industries in which addressing challenges such as electrical discharge mitigation or surface erosion can be vital. Cold spray additive manufacturing is emerging as a cutting-edge technology for polymer/composite metallization, offering a transformative approach to achieving desired material enhancements. This study employs finite element analysis (FEA) to evaluate the adhesive “bonding” strength (i.e., extraction force under impulsive dynamic loading) between single 20-micron diameter spherical metal (copper) particles and polymer (polyetheretherketone) substrates under cold spray-relevant impact conditions. Analysis of FEA simulations centers on initial impact processes parameterized by particle impact velocity and …

Design And Control Of A Versatile Modular Soft Robotic System With Integrated Resource Sharing And Self-Reconfiguration Capabilities, Joshua Knospler

Theses and Dissertations

Modular, self‑reconfigurable soft robots promise unprecedented versatility by combining the compliance of soft materials with the adaptability of modular architectures. This thesis presents an integrated system of pneumatic, bending-type soft actuator modules. Modules are compact and fully equipped with tunable magnetic and electromechanical connections for low‑power attachment and detachment and a novel power-air-communication (PAC) connector for seamless sharing of electricity, compressed air, and digital signals. This work examines two representative assemblies: ManusBot, a pinching gripper, and TendrilBot, a versatile linear configuration for various tasks. Their grasping performance, variable stiffness, and radial support capabilities are characterized. A magnetic interlock and an …

Monitoring And Mitigation Of Per- And Polyfluoroalkyl Substances (Pfas) In Urban Stormwater Runoff, Mustafizur Rahaman

Theses and Dissertations

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants known for their persistence with widespread environmental and health concerns. Urban stormwater runoff could be a non-point pollution source that transports PFAS to receiving water bodies. This study analyzed types and concentrations of PFAS in stormwater runoff from Trenton and Glassboro, New Jersey, with samples collected from high- and low-traffic areas during precipitation events in February, June, July, and August 2024. Significantly higher concentrations of PFAS were identified in high-traffic areas than low-traffic areas (p< 0.05) in both cities for most sampling events, confirming the role of traffic in PFAS dispersal. To address PFAS contamination in stormwater runoff, this study evaluated the removal of six U.S. Environmental Protection Agency (USEPA)-regulated PFAS compounds from synthetic stormwater runoff using aluminum-based water treatment residuals (Al-WTRs, by-products of the drinking water treatment process). The findings demonstrated that Al-WTRs exhibited high sorption capacities and low desorption rates for PFAS, particularly for long-chain PFAS compounds such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), supporting their potential as an economical and effective sorbent for stormwater PFAS management. Furthermore, the durability and sustained performance of Al-WTRs indicated their feasibility for future field-scale applications.

Development Of Biodegradable Mg-1zn-0.5sc Alloy & Surface Treatment Through Laser Shock Peening And Evaluation Of Microstructure & Property Correlation For Orthopedic Implants, Parameshwari R

Theses and Dissertations

Magnesium (Mg) and its alloys are of much interest as promising third-generation bio-materials for bone implant applications; however, challenges remain for the alloy's mechanical integrity and bio-corrosion behaviour. Therefore, appropriate alloying elements and surface-modification techniques are required to overcome these limitations. Zinc (Zn) and Scandium (Sc) elements were found to have good biocompatibility and biodegradability; hence, they were selected as suitable alloying elements for magnesium.

This research work aims to enhance the mechanical integrity and bio-corrosion resistance behaviour of a novel Mg-1wt% Zn-0.5wt% Sc cast alloy by laser shock peening surface treatment with multiple passes (LSP-2 Pass and LSP-3 Pass). …

Development Of Fiber Composite Joints To Improve Folding Of Deployable Arrays, Luke Q. Gardner

Theses and Dissertations

An origami-inspired deployable array, despite being commonly made from rigid materials, must be able to fold into its stowed configuration. This necessitates the employment of discontinuities between the panels of the array and the use of specialized joints to connect them. Compliant joints, with all their typical advantages, are useful in this application. Membrane hinges and lamina-emergent torsional (LET) arrays are two classes of compliant joints, or surrogate folds, which each feature unique benefits and drawbacks. Membrane hinges in principle are simple and flexible, providing a wide range of motion while experiencing little stress. However, perhaps their most robust variation, …

Contaminant Removal Of Printed 7xxx Aluminum Using The Additive Friction Stir Deposition Process, Jacob Jason Hansen

Theses and Dissertations

The development of contaminant-free additive friction stir deposition (AFSD) using 7xxx series aluminum alloys represents a significant advancement in solid-state additive manufacturing. The removal of graphite and other contaminants allows AFSD to more effectively move forward into the production space. This work demonstrates how contaminant-free depositions were made more feasible. This was accomplished via novel tool designs. These novel designs reduced process forces sufficiently that 7xxx aluminum alloys were able to be printed on commercial and research AFSD machines. Internal features such as draft angles and diffusers/chamfers help to significantly reduce actuator forces. This work also demonstrates how external tool …

Enhancing Fault Tolerance In Tmr Soft Risc-V Fpga Socs Through Failure-Driven Mitigation Strategies, Andrew Elbert Wilson

Theses and Dissertations

Field-Programmable Gate Arrays (FPGAs) leveraging soft processors, particularly those implementing the open-standard RISC-V Instruction Set Architecture (ISA), are increasingly important for space missions due to their adaptability and reconfigurability. However, their susceptibility to radiation-induced Single Event Upsets (SEUs) presents significant reliability challenges, necessitating robust fault-tolerant strategies such as Triple Modular Redundancy (TMR). This dissertation evaluates the effectiveness of TMR-based mitigation techniques for Linux-capable soft RISC-V System-on-Chip (SoC) implementations deployed on SRAM-based FPGAs operating in high-radiation environments. Using a combination of deterministic fault injection and neutron radiation testing, this work identifies critical residual single-point failure modes that persist in TMR-protected designs. …

Characterization Of Ultra-High-Speed Friction Stir Welds Made In Thin Sheet Aa6061-T4 Material, Todd Grant Lainhart

Theses and Dissertations

Friction stir lap welding (FSLW) of thin aluminum sheets in industry and in research has faced challenges in weld quality that limit welding speeds. Interfacial defects such as hooking and thinning are common defects that appear at the interface of FSLW, and researchers and process operators have traditionally reduced process parameters such as feed rate and spindle rotation to fully eliminate the defects. While such measures are successful in creating fully consolidated FSLW, feed rates for FSLW have stagnated around 1 mpm with the fastest feed rates recorded at 3 mpm, making it difficult for manufacturers to implement FSLW in …

Practicality Of Implementing Sub-Clause 8.4 [Advance Warning] Of The Fidic 2017 Red Book In Egypt, Gehad Ibrahim

Theses and Dissertations

Disputes in construction projects can cause cost and time overruns that can be detrimental to the parties involved and to the project. Several measures have been advocated by the industry’s practitioners in an attempt to avoid disputes and their adverse impacts. One of these measures is the introduction of advance warning sub-clauses in construction contracts, where the contracting parties play a proactive and collaborative role in warning each other of potential adverse impacts to the project. Such clauses have been in the NEC suite of standard construction contracts for decades and have recently found their way to the 2017 edition …

Rapid Beamformer Weight Calibration Update Method For The Advanced L-Band Phased Array Camera For Astronomy (Alpaca), Kayla Lyman Ward

Theses and Dissertations

The Advanced L-Band Phased Array Camera for Astronomy (ALPACA) is a phased array feed instrument designed for the Green Bank Telescope. It is capable of producing 40 real-time beams on the sky, widening the telescope's field of view and significantly increasing survey speed. ALPACA employs an RF-over-fiber (RFoF) signal transport system from the phased array feed front end to the digital backend. This RFoF link is expected to introduce phase delays and changes in gain through out the course of an observation, invalidating the beamformer weights previously calculated. This work presents rapid beamformer weight calibration updates for ALPACA, a method …

Development And Miniaturization Of Pad-Printed Carbon Electrodes For Antibody-Type Biosensing, Elizabeth Danielle Clark

Theses and Dissertations

Miniaturized, pad-printed carbon electrodes (PPCEs) offer a promising platform for antibody-type biosensors, enabling rapid and cost-effective point-of-care diagnostics. This study investigates the development, fabrication, and electrochemical performance of large and miniaturized PPCEs functionalized for antibody-type detection, with the eventual goal of detecting pancreatic cancer specific biomarkers. The PPCEs were made of silver- and carbon- based inks that were formulated to be pad printable and conductive and printed on polycarbonate film so they can be easily disposed of after use. Each PPCE was thoroughly cleaned with ethanol several times to ensure a clean base on which to adsorb antibodies and antigens. …

Optimization Of Pile Construction Sequence Using Cfa Machines, Omar Wael Ammar

Theses and Dissertations

In most construction projects with deep foundations, piling activities are critical to the project schedule and often fall on the critical path. The piling construction process requires a diverse range of resources, including equipment, materials, and skilful labour. Without carefully planning the construction process according to installation standards, there is a significant risk of time and cost overruns. These overruns are caused by inefficiencies such as equipment idle or lost time due to required lags between closely spaced piles. Therefore, it is essential to develop an optimized construction sequence to minimize these risks and enhance overall project efficiency. The primary …

Multi-Parameter Optimization Of Brine Desalination Using Machine Learning, Elaf Mman Seif

Theses and Dissertations

Air Gap Membrane Distillation (AGMD) is a promising desalination technology with significant potential for addressing global water scarcity. However, the interplay of operational parameters significantly impacts its performance, making optimization a challenging task. This research focuses on brine desalination as a means to mitigate the negative environmental impacts of brine disposal which will eventually help in provide a sustainable solution for handling brine while producing freshwater. The study seeks to develop a predictive model and optimize the AGMD process for efficient brine desalination. To achieve this, Response Surface Methodology (RSM) and Artificial Neural Networks (ANNs) were utilized to develop predictive …

Image-Based Models For Left Heart Flow Morphodynamics In Hypertrophic Obstructive Cardiomyopathy, Abdelrahman A. Sultan

Theses and Dissertations

Relieving flow obstruction in hypertrophic obstructive cardiomyopathy is highly effective in reducing symptoms and promoting left ventricular remodeling. However, existing characteristics in the disease, such as the systolic anterior motion of the mitral, mitral regurgitation, and papillary muscle motion, and their effect on ventricular flow and vortex formation, have not been thoroughly addressed. This study aims to develop image-based computational fluid dynamics models to evaluate flow morphodynamics in hypertrophic obstructive cardiomyopathy. A computational fluid dynamics model is constructed to investigate the interaction between inflow and outflow in hypertrophic obstructive cardiomyopathy, with a focus on how the motion of the left …

An Llm Approach For Automating The Analysis Of Bim (Ifc) Data, Miral Selim

Theses and Dissertations

This thesis introduces a novel methodology for automating the analysis of Building Information Modeling (BIM) data using LangGraph, an advanced extension of the LangChain framework, and integrating Google’s Gemini Large Language Model (LLM) with IfcOpenShell. BIM, and specifically Industry Foundation Class (IFC) files, are widely used in the construction industry for representing and managing building data. However, analyzing this data effectively remains a significant challenge due to its volume and complexity. Additionally, analyzing BIM data typically requires knowledge of different BIM software depending on the application. This research addresses this challenge by creating a workflow that utilizes LangGraph’s ability to …

Removal Of Fluoroquinolones From Water Systems Employing Rice Husk Composited Sponges Via Nanoadsorption, Dalia Kanaa

Theses and Dissertations

A novel nanocomposite of polyvinyl alcohol formaldehyde (PVF) sponge loaded with green zinc oxide nanoparticles (ZnONP) and referred to as (NP-PVF) was fabricated as a potential adsorbent of ciprofloxacin from water. A simple mechanical foaming process was used to synthesize the adsorbent. Rice husk extract was used to synthesize zinc oxide nanoparticles (ZnONP) for its phytochemicals as reducing agents. A facile and low-energy-dependent extraction method was used that did not require the use of high-temperature annealing. The synthesized nanoparticles showed a maximum UV absorption at 347 nm, which corresponds to a 3.58 eV band gap energy. FTIR confirmed the successful …

Multi-Field Quantum Conference Key Agreement Using An Integrated Photonic Green Machine, Benjamin J. Fisher

Theses and Dissertations

Quantum Conference Key Agreement (QCKA) enables a group of users to generate a shared secret key, which reduces the latency and equipment overhead of establishing multiple Quantum Key Distribution (QKD) links. Conventional QCKA protocols send a multi-photon entangled state from one user to others and a key is generated only when all photons are detected, which is inefficient at high loss and opens side-channels at the receiver side. Here, we overcome this barrier through a multi-field QCKA protocol enabled by designing, fabricating, and testing an integrated photonic Green Machine that implements an eight-mode Hadamard unitary transformation through a beam-splitter network. …

Optimized Wireless Power Transmission For Low-Cost, Energy-Efficient Internet Of Things Devices In Residential Environments, Daniel Brook Hatch

Theses and Dissertations

Wireless power transmission (WPT) offers a promising solution for powering devices in locations where traditional electrical outlets are inaccessible, such as ceilings or outdoor environments. By utilizing electromagnetic waves, such as light, WPT enables power delivery without the need for physical connections. With line-of-sight (LoS) as its primary limitation, this technology offers significant flexibility and potential for a wide range of applications, making it a compelling focus for research and innovation. Despite the advancements in WPT technologies, their practical application for powering Internet of Things (IoT) devices in real-world scenarios remains underexplored. Many IoT devices are installed in locations where …

A Modular Simulation Environment And B-Spline Trajectory Generation Methods For Multi-Agent Uav Systems, Landon D. Shumway

Theses and Dissertations

Multi-agent UAV systems present a complex challenge requiring solutions to numerous subproblems. This research addresses two key issues: simulation testing and path planning. A modular simulation environment is developed, enabling users to run diverse mission scenarios with heterogeneous UAV teams and to implement custom dynamic models and guidance laws. Additionally, two novel B-spline trajectory generation methods are proposed. The first generates time-synchronized B-spline paths for UAVs with arbitrary initial and final states in 2D space, accommodating scenarios where agents must follow predetermined speed profiles. The second guidance method converts spline paths between MINVO, Bézier, and non-uniform B-spline representations, leveraging the …

Compliant Mechanisms For Scalable Systems And Precision Deployment, Jared Rodney Hunter

Theses and Dissertations

Compliant mechanisms offer advantages in precision applications where size, scaling, and environmental effects render traditional mechanisms inadequate or likely to fail. However, designing compliant mechanisms and integrating them into larger, more complex systems remains a challenging problem. This thesis presents work that addresses this issue with analytical models and experiments on flat springs, scalable compliant mechanisms, and origami arrays. Storing and releasing energy in tiny, flat compliant mechanisms opens the door for the design of innovative actuators and products in space-constrained situations. Scaling compliant mechanisms allows novel systems to be made that can operate across scales. By designing for scalability …

Modeling And Simulation Of Tensegrity Structures With Continuous Cables, Austin R. Brown

Theses and Dissertations

This thesis presents a novel approach for modeling and simulating tensegrity structures with continuous cables. A Python-based simulation framework package was developed to address limitations in existing tensegrity modeling software, particularly the inability to model cables passing through multiple nodes. The framework utilizes virtual work methods to solve for equilibrium configurations of 2D, 2.5D and 3D tensegrity systems. Key features include: • A YAML-based input system for easy definition of tensegrity topologies. • Algorithms for handling continuous cables spanning multiple nodes. • Optimization techniques to find stable equilibrium states. • Capability to simulate 2.5D structures wrapped around cylindrical surfaces. • …

Enhancing Gpr Reliability For Concrete Infrastructure: Integrating Signal Processing And Deep Learning For Defect And Corrosion Assessment, Priyam Chowdhury

Theses and Dissertations

This research addresses the critical issue of deteriorating civil infrastructure by utilizing GPR integrated with advanced signal processing and machine learning. Employing the Conquest 100 system, four concrete slab configurations were tested: multi-layer rebar with defects, single- and double-layer rebar setups, varied rebar spacing, and pre-corroded rebars (0–30% mass loss). GPR B-scans collected over 3–60 days demonstrated that detection accuracy varied significantly with curing time, structural complexity, and moisture levels. A custom-developed Python script surpassed EKKO_Project software in rebar localization, achieving lower position errors (0.4–0.7 inches compared to 0.5–1.25 inches). Notably, the amplitude of GPR signals unexpectedly increased with corrosion …

Heat Pumps And Sustainable Building Operations: An Analysis Of Energy Efficiency, Emissions, And Life Cycle Costs, Mahdiyeh Zafaranchi

Theses and Dissertations

Heating, ventilation, and air conditioning (HVAC) systems are a major contributor to energy demand. Heat pump technologies, particularly Ground Source Heat Pumps (GSHPs) and Air Source Heat Pumps (ASHPs), have emerged as key solutions to reduce energy use worldwide. However, their adoption is challenged by economic, operational, and environmental trade-offs. This dissertation develops a comprehensive framework for evaluating the energy efficiency, lifecycle emissions, and cost-effectiveness of GSHP and ASHP systems in sustainable building operations. Through advanced energy modeling, lifecycle assessments (LCA), and lifecycle cost (LCC) analyses, this research provides data-driven insights to optimize heat pump system selection. This study is …

Study Of Capital And Operation Costs For Reverse Osmosis Desalination Plants, Habiba Mahdy Mohamed

Theses and Dissertations

Desalination is a progressively common solution to supply freshwater in numerous parts of the globe where this resource falls short. Among all desalination techniques, seawater reverse osmosis (SWRO) is the most globally prevalent technology. Evaluating a desalination technology's cost-effectiveness is essential to ensure a well-designed plant can be implemented successfully and within an acceptable budget. In the Egyptian context, where water scarcity heightens the urgency of effective resource allocation, economic indicators such as capital expenditure (CAPEX) and operational expenditure (OPEX) are pivotal in shaping policy and planning decisions. Adopting this integrated financial perspective ensures that desalination projects are not only …

Investigating Solvent Effects On Crystallization Kinetics, Ibrahim Joel

Theses and Dissertations

The use of crystallization for separation is not a recent phenomenon. However, the development of efficient crystallization processes is continually being challenged by the complexity and high cost of new drug substances, coupled with stringent regulatory requirements, which add to the uncertainty surrounding drug launches by pharmaceutical enterprises. Accurate characterization of crystallization kinetics is a key step in crystallizer design, which can be influenced by several factors, including process conditions, scale, and the measurement techniques used for tracking particle evolution. These factors often lead to inconsistencies between kinetic studies, hindering rapid implementation within industrial contexts. This thesis presents a case …