Engineering Commons^™

The Impact Of Pac-Loaded Polymer Membrane Thickness On Chloroform Removal And Comparison Of Solvent And Thermal Membrane Regeneration Methods, Yizhi Hou, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Powdered activated carbon (PAC) has better adsorption performance than granular activated carbon (GAC) and is widely used in water purification. In most cases, PAC is dosed into water directly, then precipitated as sludge, and landfilled. In this study, PAC was mixed with a polymer and dissolved in dimethylformamide (DMF) solvent to form a PAC-loaded membrane, which was then tested for chloroform removal. The chloroform adsorption capacity of the PAC membrane increased with increasing membrane thickness because of higher carbon loading. However, regardless of membrane thickness, the flux of the PAC membranes was similar since flux resistance predominantly occurred at the …

Process Modeling Of Composites For Automated Fiber Placement, Von Clyde Jamora

Mechanical & Aerospace Engineering Theses & Dissertations

Fiber-reinforced composites are available in various material systems, each requiring specific manufacturing techniques to exploit their unique properties fully. Systems such as woven fabrics and preimpregnated fibers employ distinctive methods to harness these properties effectively. For instance, non-crimp fabrics (NCF) use high-pressure resin transfer molding and prepregs, like IM7-8552, use manufacturing method called automated fiber placement (AFP). However, these manufacturing processes often introduce deposition features that can evolve into defects. Their occurrence and impact on morphology must be predicted using experimentally informed finite element models. The research began with compaction experiments on NCF fabric, leading to the development of a …

Development Of A Conceptual Framework For Complex System Governance (Csg) Performance Measurement, James Hartwell Rutherford

Engineering Management & Systems Engineering Theses & Dissertations

Within the Complex System Governance (CSG) paradigm, system performance is regulated by nine metasystem governance functions, which provide control, communication, coordination, and integration. However, CSG has lacked a fully developed model or language to richly articulate system performance at a conceptual level. The purpose of this research was to develop a systems theory-based conceptual framework to measure the performance of CSG metasystem governance using an inductive research design.

Although ‘good performance’ may seem like an obvious idea, the current literature on performance measurement across many disciplines and contexts contains vastly inconsistent uses of the word ‘performance.’ Both researchers and practitioners …

An Integrated Space Test Lexicon: A Taxonomy For The Integrated Test And Evaluation Of Space Systems, Stephen K. Tullino, Andrew S. Keys, Robert A. Bettinger, Amy M. Cox, David R. Jacques

Faculty Publications

The proposed Integrated Space Test Lexicon is intended to amalgamate the numerous definitions of integrated (IT or IT&E), development test (DT or DT&E), and operational test (OT or OT&E) into unified, service-wide definitions, aligned with the Space Test Enterprise Vision. Refining such definitions will help distill the core characteristics of these fundamental test types to first identify space system activities composing what is traditionally known as DT and OT, then to provide a means of how these activities fit into the IT paradigm and support space system development. In forging a common understanding of how DT and OT support space …

Skilled Labor Shortage In Construction: Deep Dive Of Impactful Factors And Influential People Of The Decision-Making Process, Nicholas B. Hardy

LSU Doctoral Dissertations

The skilled labor shortage is well documented from a historical perspective via studies focusing on various construction trades such as carpentry, mechanical, electrical, plumbing, and tile setters. Causes of such shortages such as industry image, college as a preferred choice after high school, and construction being a last resort have been investigated extensively. Consequently, possible solutions ranging from amplifying shop classes in high school to intensifying recruiting efforts for union training programs have all been addressed throughout the last 40 years. However, recent studies have focused on identifying the magnitude and reach of the skilled labor gap while limited attention …

Adopt: An Environmentally-Friendly System For Alerting Drivers To Occluded Pedestrians Traffic, Abrar Abdulrahman Alali

Computer Science Theses & Dissertations

The emergence of sensing technologies and vehicular communications has brought significant opportunities for enhancing pedestrian safety on city streets. However, existing solutions rely on costly technologies such as computer vision and trajectory prediction to detect crossing pedestrians, while they have limits in detecting pedestrians who are occluded by parked cars. Despite the presence of collaborative perception by surrounding vehicles and infrastructure, there is a notable absence of incorporating existing parked cars themselves due to their insufficiency in detecting pedestrians and communicating with other cars while they are turned off. Furthermore, accommodating pedestrians on streets has been linked to an additional …

Safe And Efficient Operation Of Mobile Robots In Indoor Environments: A User-Centric Shared Control System With High-Level Navigation Capabilities, Ahmet Saglam

Electrical & Computer Engineering Theses & Dissertations

Hospitalization and isolation can be a traumatic experience for immunocompromised children, especially because they are separated from their families and friends. Social robots have been proposed as a way to improve the quality of care for children hospitalized in isolation by providing alternative means of social interaction and support. Remote control of such robots in a hospital setting, particularly where safety is a major concern, can be a daunting task for young patients.

This dissertation introduces a multilevel shared control system for mobile robots, specifically companion robots in hospital-like indoor spaces. The system integrates user inputs with algorithmic semi-autonomous control …

Hydrologic Modeling Of The Lower Chesapeake Bay Watershed Using Hecc-Hms With Implications For Future Coupled Coastal Modeling, Christopher Leonard Frost

Civil & Environmental Engineering Theses & Dissertations

This study explores the hydrological methodology for modeling a coastal watershed basin using the US Army Corps of Engineers hydrologic software, HEC-HMS with an objective of being able to create riverine boundary conditions that could be applied to a coupled compound flood model. Compound flooding is defined as high water inundation event that occurs due to the simultaneous occurrence of multiple flooding drivers. The Atlantic Seaboard and the Gulf of Mexico regions of the United States account for most of the compound events observed in the United States with a higher occurrence caused by hurricanes from July to November. In …

Flying Wing Aerodynamic Design And Airbrake Integration, Philip Lawson Mantz

Mechanical & Aerospace Engineering Theses & Dissertations

During the 2022-2023 Academic year, the defense contractor, AeroVironment, tasked the Unmanned Aerial Systems Laboratory at Old Dominion University with designing an autonomous drone platform. A brief summary of the aerodynamic requirements included that the drone should cruise at a target cruise speed of 30m/s, the drone would operate up to an altitude of 1500m and be able to land within a 20m radius of a designated landing spot. The laboratory chose a flying wing model. Additionally, the aircraft would have an airbrake system integrated into the platform.

The aerodynamic requirements were configurated through the use of a ‘constraint diagram’. …

Zero Dynamics Attacks On Unknown Bilinear Systems: Vulnerability And Detection, Mohammad Aminul Haq

Electrical & Computer Engineering Theses & Dissertations

Critical infrastructure requires a safe and secure operating environment because of its significant impact on society. Its large-scale size and distributed sensors and actuators make it vulnerable to cyber-physical attacks. A zero dynamics attack is a type of cyber-physical attack where an adversary keeps the output of the target constant (classically zero), while forcing some of the internal states to deviate from their nominal values. Most of the existing work in the literature assumes the system dynamics are linear and available to an adversary. The first goal of this dissertation is to show that an adversary can successfully execute a …

Mesostructure Reconstruction Of Prepreg Platelet Molded Composite With Artificial Intelligence, Richard Larson

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg platelet molded composites (PPMC) are long, discontinuous fiber reinforced polymer materials. PPMC are an important subcategory of composite materials as they are processible into geometrically complex structures and can be produced via high-throughput manufacturing processes, however they have higher stiffness and strength as compared to traditional discontinuous fiber reinforced polymers. However, there is inherent randomness in the structure of PPMCs and as such, PPMC parts frequently require per part testing that is cost prohibitive.

Herein, a method using artificial intelligence is proposed as a more cost-effective method of inspecting PPMC parts. Different artificial intelligence (AI) architectures are explored to …

A Kinematic Analysis Of The Shoulder During The Volleyball Attack Using Euler And Helical Axis Methods, Victoria Jolliff

Biomedical Engineering Theses & Dissertations

The shoulder is a complex joint with a wide range of motion, including flexion, extension, abduction, adduction, and internal and external rotation. In volleyball, repetitive overhand movements can cause shoulder overuse injuries. The primary offensive move, the attack, involves the approach, arm cocking, arm acceleration, and follow-through phases. Motion capture analysis and techniques like calculating Euler angles and rotation about a mean helical axis can evaluate shoulder movements. This study aimed to calculate shoulder movements during each phase of the volleyball attack using the Euler angle YXY sequence and the helical axis method. Different attack types, such as cross-court and …

Harnessing Social Media For Disaster Response: Intelligent Identification Of Reliable Rescue Requests During Hurricanes, Wael Khallouli

Engineering Management & Systems Engineering Theses & Dissertations

Hurricanes pose a significant threat to both human lives and infrastructure. Decision-makers face substantial challenges during such events, as they must act quickly to address victims’ needs. Social media platforms provide a valuable source for quick and real-time information. Recent hurricane events have shown that people turn to social media to call for help when official communication channels, such as 911, are overwhelmed. However, extracting actionable information from the massive number of messages posted on social media is challenging. Furthermore, verifying social media messages posted by the public is a critical concern for disaster response practitioners, making them hesitant to …

Improving Tcp Performance Using P4-Programmable Data Planes, Jose Antonio Gomez Gaona

Theses and Dissertations

The Transmission Control Protocol (TCP) forms the foundation of reliable end-to-end communication and is widely used by many applications for efficient data transfers across the Internet. TCP relies on various congestion control algorithms (CCAs) to manage its response to network congestion. These algorithms ensure fairness among competing flows and optimize the use of available bandwidth. However, since TCP is deployed within end hosts, its capacity to attain visibility of network events is constrained. This limitation arises from the closed nature of non-programmable network devices, which prevents researchers from exploring customized actions in response to network events. Recently, the emergence of …

Strengthening Power Systems For Net Zero: A Review Of The Role Of Synchronous Condensers And Emerging Challenges, Hamid Soleimani, Daryoush Habibi, Mehrdad Ghahramani, Asma Aziz

Research outputs 2022 to 2026

System strength is both supplied and demanded in a power system during normal operations and in the presence of disturbances. This is characterised by stable voltage and frequency, supporting renewable generation such as wind and solar. Because the retirement of synchronous generators reduces system strength supply, and the connection of new inverter-based resource (IBR) generators increases demand, there is an urgent need for new sources of system strength. This paper provides an overview of the challenges brought about by grid modernisation. It highlights tangible solutions provided by synchronous condensers (SCs) to bolster grid strength, stability, and reliability while accommodating the …

Derivative Propagation Through Vortex Particle Method Simulation, Eric Green, Andrew Ning

Faculty Publications

Automatic differentiation (AD) is a powerful tool for evaluating numerical derivatives. In particular, reverse-mode AD provides numerical gradients in a way that is insensitive to the number of input variables. This makes reverse-mode AD well-suited for solving large optimization problems. However, reverse-mode AD has a particularly large associated memory cost because most intermediate values in operations need to be cached. This is problematic for large problems such as aerodynamics simulations, though, since the memory requirements can quickly become impractical. The solution implemented in this work is to provide analytic pullback expressions for functions for which many of the intermediate values …

Trajectory Optimization Of Evtol And Conventional Aircraft: A Comparative Analysis Of Vortex Particle Method And Vortex Lattice + Blade Element Momentum Theory, Andrew Tagg, Ryan Anderson, Cibin Joseph, Andrew Ning

Faculty Publications

Trajectory optimization of aircraft transition maneuvers can significantly influence the design of these systems, particularly when making decisions about aircraft geometry, propulsion sizing, and control system design. This paper presents the trajectory optimization of air vehicles including electric vertical takeoff and landing (eVTOL) as well as conventional aircraft. The study evaluates the influence of fidelity in trajectory design by comparing the use of two aerodynamic methods in the context of trajectory optimization. The mid-fidelity method utilizes a vortex lattice method (VLM) to model lifting surfaces while employing blade element momentum theory (BEMT) to model rudimentary rotor-wing interactions. The high-fidelity approach …

Solving Unsteady Potential Flow Problems In O(N) Time, Ryan Anderson, Andrew Ning

Faculty Publications

Design of vertical takeoff and landing aircraft is challenging in part due to significant aerodynamic interactions between rotors and wings. Computational models can aid in their design, but are computationally expensive. 3-D panel methods coupled with vortex particle wakes offer an attractive solution, but solving for the panel strengths scales poorly for large problems. Multigrid methods, such as Krylov subspace methods in conjunction with the fast multipole method (FMM), have been demonstrated to reduce the scaling to O(𝑁). We explore the performance and limitations of the Krylov-FMM method, traditional matrix-powered GMRES, LU decomposition, and a novel O(𝑁) multigrid approach to …

High–Strength Porous Tinbzrtafe Alloys Fabricated By Sintering Of Nanocomposite Powder Precursor With Space Holder Technique, Yuhua Li, Yuxin He, Rong Zhao, Libin Niu, Juxin Qu, Lai Chang Zhang

Research outputs 2022 to 2026

Although introducing high porosity in biomedical Ti alloys can reduce their elastic modulus and promote new bone ingrowth, relieving the stress–shielding effect and implant failure, this also causes a decline in the alloys’ mechanical strength. In this work, a new preparation method for the high–strength and high–porosity Ti65Nb23.33Zr5Ta1.67Fe5 (TNZTF, at.%) alloy was suggested by sintering nanocomposite powder precursor in combination with the use of a space holder technique, in which NH4HCO3 is adopted to achieve a porous structure. The highly porous TNZTF alloy possesses a homogeneous fine–grained microstructure consisting of equiaxed α–Ti and a small amount of FeTi2, the latter …

Dark Knights: Exploring Resilience And Hidden Workarounds In Commercial Aviation Through Mixed Methods, Riana Steen, James Norman, Johan Bergström, Gitte F. Damm

Aviation Faculty Publications

In this study, the duality of adaptive capacity in aviation safety is examined, where the need for resilience of frontline workers conflicts with the expectations and assumptions of upstream entities, leading to system brittleness. We explore three critical categories: responsibilization, the application of practical wisdom in navigating challenging situations, and the unrecognized sacrifices that accompany adaptation. A qualitative research design is used, using three focus groups consisting of pilots in a European airline, the airline’s safety department, and the respective civil aviation authority. The study's findings reveal i. significant organizational constraint and pressure on pilots, resulting in workarounds, personal playbooks, …

Modelling, Design, Control, And Implementation Of Advanced Isolated Dc/Dc Converters For Renewable Energy Applications, Yuqi Wei, Quanming Luo, Di Mou, Shuang Zhao, Marco Liserre, H. Alan Mantooth

Electrical Engineering and Computer Science Faculty Publications and Presentations

Demand for high-efficient isolated DC/DC converters to achieve energy transfer among renewable energy sources, energy storage elements, and loads is increasing because of renewable energies’ increasing market penetration. Traditional converters pose significant challenges due to the wide voltage range operation nature of these components. Interest in improving the power converters’ performances for renewable energy applications is growing rapidly. Researchers are exploring accurate analysis methods, optimal design, and novel control strategies to improve the power converters’ performance. These strategies can improve the converters’ performance without any modifications to the traditional hardware. In addition, design automations are drawing more and more attention. …

Electrical And Morphological Investigation Of A Fe(Ii) Based Spin Crossover Complex And Its Composite, Rifat Mahbub

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Spin crossover (SCO) complexes have unique properties of switching their spin state upon perturbations like temperature, pressure, light, etc. Along with the spin state, different properties vary like structural, electrical, magnetic, optical properties. This enables these materials to be potentially used in various applications like molecular electronics, memory devices, switching devices, sensors and many more. To incorporate spin crossover materials into devices with efficient performance, the electrical behavior needs to be understood. This dissertation aims to investigate the effect of crystal structure on the electrical properties of iron(II) triazole spin crossover complex and how it can be modified for better …

Integrating Remote Sensing And Machine Learning To Determine Past, Current And Future Crop Water Use From The Nubian Sandstone Aquifer System, Moaz Ishag

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The agriculture sector is a significant consumer of water, and sustainable water use begins with monitoring irrigated land. Delineating irrigated land supports decision-makers and promotes the sustainable use of this crucial resource. This study focuses on the Nubian Sandstone Aquifer System (NSAS), the largest aquifers in the world, which spans Egypt, Sudan, Libya, and Chad. The study aims to: 1) quantify the increase in irrigated hectares (both pivot and non-pivot) from 2000-2001 to 2023-2024; 2) identify major irrigated crop types and their water requirements; and 3) quantify groundwater crop water use from the NSAS using remote sensing via the Google …

Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Lead toxicity has hindered the wide applications of lead halide perovskites in optoelec- tronics and bioimaging. A significant amount of effort has been made to synthesize lead-free halide perovskites as alternatives to lead halide perovskites. In this work, we demonstrate the feasibility of synthesizing CsSnI3-based powders mechanochemically with dual light emissions under ambi- ent conditions from CsI and SnI2 powders. The formed CsSnI3-based powders are divided into CsSnI3-dominated powders and CsSnI3-contained powders. Under the excitation of ultraviolet light of 365 nm in wavelength, the CsSnI3-dominated powders emit green light with a wavelength centered at 540 nm, and the CsSnI3-contained powders …

Investigation Of Emissions Characteristics Of Natural Gas Engines With Prechamber Enabled Mixing Controlled Combustion, Johnathan Michael Ronsman

Master's Theses (2009 -)

Increasingly stringent emissions regulations have motivated the exploration of ways to decarbonize the internal combustion engine (ICE). Alternative fuels are of interest as they can easily be implemented with existing infrastructure. Among these alternative fuels, natural gas stands out due to its large abundance and high hydrogen-to-carbon ratio, which can significantly reduce CO2 emissions. Due to its low reactivity, most natural gas engines today are premixed lean burn spark ignited (SI) engines. These engines produce criteria pollutants, such as nitrogen oxides (NOx) and carbon monoxide (CO), but due to their premixed nature, also produce relatively large amounts of unburned methane …

Design And Verification Of A Planar, Programmable, Compliant Hand For Use In General Open-Loop Constrained Manipulation, Jacob Frye

Master's Theses (2009 -)

Conventional robots are adept at performing tasks where the desired absolute position of the robot's end effector is well defined. However, these robots will struggle with tasks in which the desired position is poorly defined, subject to variation, or determined by contact with a constraint with positional uncertainty. This problem can be solved by introducing compliance to the system, either active or passive. Active compliance uses force feedback to make corrective motions, but is limited in speed and experiences higher contact forces than passive systems. Passively compliant systems are capable of realizing the necessary compliance for a given task but …

Advancing Understanding Of Opinions, Perceptions, And Knowledge In Underrepresented Communities In The El Paso Region To Promote Electric Vehicles And Electrified Infrastructure Use To Reduce Environmental Impacts, Liliana Lozada-Medellin

Open Access Theses & Dissertations

As the transportation and automotive industries continue growing, environmental and human health impacts remain a growing concern for planners, policy-makers, constructors, and the public as well (Krause et al., 2013; Larson et al., 2014). Although Electric Vehicles (EVs) are entering the market as a green technology solution to counteract greenhouse gas (GHG) emissions from internal combustion engine vehicles (ICEVs), there are still barriers that need to be overcome for widespread diffusion and adoption as the best solution. These include disseminating basic information about the technology for public awareness, considering equity concerns, and ensuring equitable access to infrastructure for all (L. …

Impact Of Non-Thermal Plasma Generated Using Air And Nitrogen On Functional Properties Of Milk Protein Dispersions, Nikitha Modupalli, Md Mahfuzur Rahman

Food Science Faculty Publications and Presentations

This study focuses on improving the functionalities of milk protein concentrate (MPC) using a nonthermal plasma jet and plasma-activated water (PAW) with atmospheric air and nitrogen as source gases. The 5% and 10% MPC dispersions were directly treated with a plasma jet, and PAW was used to make the MPC dispersions. The dispersions were analyzed for changes in protein structure and functional properties. The treatment altered the secondary structure of MPC protein structure by increasing β-components and changing the order of random coils. The solubility of the PAW-treated 5% protein dispersions doubled due to plasma-induced modification of hydrophilic and covalent …

Microstructural Evolution In A Precipitate-Hardened (Fe0.3ni0.3mn0.3cr0.1)94ti2al4 Multi-Principal Element Alloy During High-Pressure Torsion, Matthew Luebbe, Jiaqi Duan, Peipei Cao, Zhaoping Lu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Yuzi Liu, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Multi-principal element alloys demonstrate high strength, thermal stability, and irradiation resistance, making them excellent candidate materials for applications in nuclear reactors and other harsh environments. Some studies have examined the use of high-pressure torsion to strengthen MPEAs through grain size reduction and strain hardening. However, no studies have investigated the effect of HPT on secondary phases (precipitates) within an MPEA. Two alloys, (Fe_0.3Ni_0.3Mn_0.3Cr_0.1)₉₄Ti₂Al₄ containing Ni(Ti, Al) B2 phase, and CrFe σ phase, and single-phase Fe_0.3Ni_0.3Mn_0.3Cr_0.1, were fabricated by casting …

Predicting Iot Distributed Ledger Fraud Transactions With A Lightweight Gan Network, Charles Rawlins, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Decision-making and consensus in traditional blockchain protocols is formulated as a repeated Bernoulli trial that solves a computationally intense lottery puzzle, called Proof-of-Work (PoW) in Bitcoin. This approach has shown robustness through practice but does not scale with increasing network size and generation of new transactions. Resource constrained Internet of Things (IoT) networks are incompatible with full computation of schemes like Bitcoin's PoW. Our effort proposes a first step towards an alternative consensus using machine learning-based decision-making with prediction of fraud transactions to alleviate need for intense computation. To improve base approval probabilities for fraud detection in an ideal security …