Engineering Commons^™

Optimal Global Supply Chain And Warehouse Planning Under Uncertainty, Avnish Kishor Malde

All Dissertations

A manufacturing company's inbound supply chain consists of various processes such as procurement, consolidation, and warehousing. Each of these processes is the focus of a different chapter in this dissertation.

The manufacturer depends on its suppliers to provide the raw materials and parts required to manufacture a finished product. These suppliers can be located locally or overseas with respect to the manufacturer's geographic location. The ordering and transportation lead times are shorter if the supplier is located locally. Just In Time (JIT) or Just In Sequence (JIS) inventory management methods could be practiced by the manufacturer to procure the raw …

Controlled Manipulation Of Droplets On Fibers: Fundamentals And Printing Applications, Yueming Sun

All Dissertations

In this dissertation, the drop interactions with a single fiber is discussed under an application angle for the development on new Drop-on-Demand (DOD) printhead using a fiber-in-a-tube platform[1] to print highly viscous materials[2]. To control the drop formation and manipulation on fiber, one needs to know how the fiber wetting properties and the fiber diameter influence drop formation. And then, one needs to know the effects of fiber movement in the device on drop formation. These two questions constitute the main theme of this dissertation.

Before this study, it was accepted that the liquids could not form axisymmetric droplets if …

Evaluation Of Life Cycle Costs, Benefits, And Public Perceptions Of Greywater Reuse Systems For Supplementing Conventional Water Delivery, Sreeganesh Reddy Yerri

All Dissertations

The water utility industry is under enormous pressure to meet the challenges of increasing demands due to population growth, lifestyle changes, and depleting freshwater resources. The current and predicted future deficit scenarios challenge water supply managers to come up with a sustainable and reliable alternative source while making the supply infrastructure smarter and resilient. One such alternative source is the greywater that is available at the point of consumption itself. With certain limitations, there have been studies performed to evaluate the life cycle costs and expected monetary benefits of decentralized greywater reuse systems, but the public and health bureaus are …

Protection Of Microgrids: A Scalable And Topology Agnostic Scheme With Self-Healing Dynamic Reconfiguration, Phani Harsha Gadde

All Dissertations

Momentum towards realizing the smart grid will continue to result in high penetration of renewable fed Distributed Energy Resources (DERs) in the Electric Power System (EPS). These DERs will most likely be Inverter Based Resources(IBRs) and will be an integral part of the distribution system in the near future. The drive towards resiliency with these IBRs will enable a modular topology where several microgrids are tied together, operating synchronously to form the future EPS at the distribution level.

Since the microgrids can evolve from existing distribution feeders, they will be unbalanced in load, phases, and feeder impedances. A typical control …

Feasibility Of Using Ultra-High-Performance Concrete (Uhpc) As A Repair Material Durability Performance, Rebar Coating, And Bond Characterization, Haitham Hussein

All Dissertations

Ultra-High Performance Concrete can be a very good material for use in repair works. The ability of chloride ions to pass through repaired concrete layers is suppressed if an impermeable concrete like UHPC is used. However, thickness of the UHPC layer and the orientation of the repair layer relative to the direction of chloride ingress may influence its effectiveness. This study is an attempt to evaluate the effect of varying thicknesses and cross sections areas of UHPC over a precast concrete and the direction of the UHPC layers relative to the direction of chloride ion movement on the resistance offered …

Integration Of Techno-Economic Analysis (Tea) And Life Cycle Assessment (Lca) For Sustainable Process Design, Roksana Mahmud

All Dissertations

For sustainable design, technology developers need to consider not only technical and economic aspects but also potential environmental impacts while developing new technologies. Techno-economic analysis (TEA) evaluates the technical performance and economic feasibility of a technology. Life cycle assessment (LCA) evaluates the potential environmental impacts associated with a product system throughout its life cycle from raw material extraction to disposal. Generally, TEA and LCA are performed separately for technology assessment. Understanding of the trade-off between economic and environmental performances is crucial for sustainable process design, which is not fully available if TEA and LCA is performed separately. In contrast, integration …

Influence Of Specimen Geometry And Anisotropy On Dynamic Modulus Of Asphalt Mixes In South Carolina, Srinivasan Nagarajan

All Dissertations

The objective of this study was to characterize the variability of dynamic modulus of asphalt mixes in South Carolina on the basis of geometry and anisotropy. High priority mixes Surface Type B, and C; Intermediate Type B and C and Base Type A from three different days of production were collected from seven different contractors each having a different aggregate source and the dynamic modulus was measured using the Asphalt Mixture Performance Tester (AMPT) at temperatures of 40, 70, 100 and 130℉ (4.4, 21.1, 37.8, and 54.4℃) and at frequencies of 25, 10, 5, 1, 0.5, and 0.1 Hz. One-way …

Algorithm Optimization And Hardware Acceleration For Machine Learning Applications On Low-Energy Systems, Jianchi Sun

All Dissertations

Machine learning (ML) has been extensively employed for strategy optimization, decision making, data classification, etc. While ML shows great triumph in its application field, the increasing complexity of the learning models introduces neoteric challenges to the ML system designs. On the one hand, the applications of ML on resource-restricted terminals, like mobile computing and IoT devices, are prevented by the high computational complexity and memory requirement. On the other hand, the massive parameter quantity for the modern ML models appends extra demands on the system's I/O speed and memory size. This dissertation investigates feasible solutions for those challenges with software-hardware …

Tessellated Structural-Architectural Systems: Experimental Testing And Interdisciplinary Student Projects, Grace F. Crocker

All Dissertations

This dissertation discusses a new structural system called a Tessellated Structural-Architectural (TeSA) system. These TeSA systems utilize architecturally appealing tessellations in load-bearing structures comprised of interlocking tiles in a pattern. This dissertation focuses on the design, construction, and structural behavior of these TeSA systems, as well as their value as an interdisciplinary learning tool.

This dissertation has 4 research objectives: 1) Demonstrate the fabrication and construction of a precast reinforced concrete (RC) TeSA shear wall system; 2) Measure the structural performance of the RC TeSA shear wall system; 3) Compare simplified shear and flexural analysis methods for RC TeSA shear …

Quantum-Mechanical Evaluation Of Defects In Uranium-Bearing Materials, Megan Hoover

All Dissertations

Quantum-mechanical calculations using density functional theory with the generalized gradient approximation were employed to investigate the effects dopants have on the uranium dioxide (UO₂) structure. Uraninite is a common U⁴⁺ mineral in the Earth's crust and an important material used to produce energy and medical isotopes. Though the incorporation mechanism remains unclear, divalent cations are known to incorporate into the uranium dioxide system. Three charge-balancing mechanisms were evaluated to achieve a net neutral system, including the substitution of (1) a divalent cation for a tetravalent uranium atom and oxygen atom; (2) two divalent cations for a tetravalent …

Computational Characterization Of Nonwoven Fibrous Materials: Transport And Wetting Properties, Fang Wang

All Dissertations

Nonwoven fibrous materials represent a platform of flexible material substrates. Nonwovens are widely used in the production of napkins, paper, filters, wound covers and face masks. In addition, for many applications, nonwoven materials interact with fluids. For example, in filtration applications, nonwoven materials are used to clean fluids containing solid particles or emulsified droplets. The filtration performance is affected not only by the geometrical arrangement of fibers in non-woven materials but also wettability of fibers. Understanding the transport properties of nonwoven materials and interactions between the dispersed droplets and solid substrate is crucial for the design and optimization of filter …

Multi-Scale Vertebral-Kinematics Based Simulation Pipeline Of The Human Spine With Application To Spine Tissues Analysis, Mohd Jaradat

All Dissertations

This study developed an analytical tool for understanding spine tissues’ behavior in response to vertebral kinematics and spine pathology over a range of body postures. It proposed a novel pipeline of computational models based on predicting individual vertebral kinematics from measurable body-level motions, using musculoskeletal dynamics simulations to drive the vertebrae in corresponding spine FEMs.

A reformulated elastic surface node (ESN) lumbar model was developed for use in MSD simulations. The ESN model modifies the lumbar spine within an existing MSD model by removing non-physiological kinematic constraints and including elastic IVD behavior. The model was scaled using subject-specific anthropometrics and …

Mitral Valve Tissue Engineering - A Dynamic Model For Investigating The Mechanism Of Valvular Pathology, Collin Owens

All Dissertations

Heart valve disease affects an average of 2.5% of the population in the United States. The mitral valve (MV) is the most complex of the heart’s four valves and is most associated with the disease by exhibiting altered extracellular matrix (ECM) which translates into stenosis or regurgitation. These diseases are typically degenerative in nature and can be accelerated by risk factors such as diabetes and hypertension. With diabetes and hypertension affecting 425 million and 1.39 billion people worldwide, further investigation into these risk factors is warranted. This study aims to develop and test an in vitro model of MV disease. …

3d Printed Multicomponent Polymer Based Materials Via Hybrid Filaments: Fabrication And Characterization, Erik Antonio

All Dissertations

Additive manufacturing, also known as 3D printing, promises a manufacturing revolution for both industry and academic circles. One of the most widely used method of 3D printing is Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF), which requires a thermoplastic filament to be directed towards a heating block and then deposited via extrusion layer by layer to produce a finished part. However, there are significant issues with this technology, mainly a limitation on the materials available for use and mechanical property deficiencies when compared to traditional manufacturing. These issues are brought about by the temperature limited nature of the …

Machine Learning-Enabled Model-Based Condition Assessment Of Water Pipelines By Leveraging Hydraulic Monitoring Data, Ahmad Momeni

All Dissertations

Overpopulation and climate change have direly challenged the freshwater resources, specifically potable water supplied by water distribution networks (WDNs). One aggravating issue associated with the WDNs is associated with the pipeline leakage, which accounts for almost 20% of freshwater loss in WDNs throughout the US. Leakage detection and severity measurement are of top
asset management priorities in water utilities to minimize and mitigate complicated risks attributed to background and burst leakage. Accordingly, decline in other pipe condition parameters such as effective hydraulic diameters and roughness coefficients, which are complex and uncertain in nature, abets leakage by worsening the WDN status …

Adaptive Design And Flexible Approval Of Clinical Trials, Saeid Delshad Sisi

All Dissertations

Dose-finding clinical trials are among the most critical cornerstones of the healthcare system. In this broad research area, there are many decision making problems that are extremely challenging to address. However, a small improvement may result in significant benefits to the society. Dose-finding clinical trials are extremely expensive and require multiple time-consuming and complicated R&D phases. Despite all the costs and the long time these trials need to conclude (on average over ten years for each new drug/technology), only less than 15\% of these trials successfully end up in a new approved drug entering the market. This problem is even …

Use Of A Trial Function Method To Semi-Analytically Simulate Matrix Diffusion In Heterogeneous And Fractured Media, Kien Trung Pham

All Dissertations

A semi-analytic trial function model is applied to simulate matrix diffusion in systems of parallel fractures, 2-D/3-D discrete fracture networks, and in 3-D heterogeneous media. The trial function model gives low normalized root mean square error (NRMSE) when compared to the parallel fracture analytical solution over a range of fracture spacing, with considerations for retardation and decay. The semi-analytic trial function model is efficient in time and maintains less than 6% NRMSE when it simulates matrix diffusive transport in 2-D/3-D discrete fracture networks (DFN). The model can predict DFN plume within a few meters of accuracy compared to fine-grid DFN …

A Novel Computationally Efficient Ai-Driven Generative Inverse Design Framework For Accelerating Topology Optimization And Designing Lattice-Infused Structures, Darshil Patel

All Dissertations

Multiscale topology optimization (TO) provides an inverse design computational framework for designing globally and locally optimized hierarchical structures. Triply periodic minimal surfaces (TPMS), a subclass of parametrically-driven lattice structures, exhibit unique properties such as large surface area, significant volume densities, and good strength-to-weight ratio, which makes them favorable for novel engineering applications. The recent advances in additive manufacturing and its ability to fabricate high-resolution structures have spurred interest in multiscale TO and TPMS for computationally designing finer and high-resolution designs. While multiscale TO and TPMS bring transformative opportunities in various applications, their potential for everyday use remains idle due to …

Subwavelength Engineering Of Silicon Photonic Waveguides, Farhan Bin Tarik

All Dissertations

The dissertation demonstrates subwavelength engineering of silicon photonic waveguides in the form of two different structures or avenues: (i) a novel ultra-low mode area v-groove waveguide to enhance light-matter interaction; and (ii) a nanoscale sidewall crystalline grating performed as physical unclonable function to achieve hardware and information security. With the advancement of modern technology and modern supply chain throughout the globe, silicon photonics is set to lead the global semiconductor foundries, thanks to its abundance in nature and a mature and well-established industry. Since, the silicon waveguide is the heart of silicon photonics, it can be considered as the core …

Improving Patient Safety, Patient Flow And Physician Well-Being In Emergency Departments, Vishnunarayan Girishan Prabhu

All Dissertations

Over 151 million people visit US Emergency Departments (EDs) annually. The diverse nature and overwhelming volume of patient visits make the ED one of the most complicated settings in healthcare to study. ED overcrowding is a recognized worldwide public health problem, and its negative impacts include patient safety concerns, increased patient length of stay, medical errors, patients left without being seen, ambulance diversions, and increased health system expenditure. Additionally, ED crowding has been identified as a leading contributor to patient morbidity and mortality. Furthermore, this chaotic working environment affects the well-being of all ED staff through increased frustration, workload, stress, …

Modeling, Estimation, And Optimal Control Of Lithium-Ion Battery At Cell And System Level, Hamidreza Mirzaei

All Dissertations

Lithium-ion batteries (LIBs) have been regarded as a crucial technology for electrifying a variety of applications, ranging from powering computers, phones, and hybrid electric vehicles (HEVs) to being a critical part of the modern centralized and distributed power grids. Battery systems performance is governed by embedded battery management systems (BMSs). The BMS includes battery state estimation algorithms and control rules, and it acts as the brain of battery-powered systems. The purpose of this research is to address unresolved difficulties associated with control algorithms in BMSs at all levels, from single battery cells to battery packs in hybrid electric vehicles (HEVs).\\ …

Tissue-Engineered Living Pulmonary Valve For Young Adult Patients, Erica Hoskins

All Theses

Cardiovascular disease (CVD) is a non-communicable disease responsible for 659,000 deaths annually in the United States. While CVD can affect all components of the cardiovascular system, heart valve disease is responsible for 25,000 deaths yearly. Of specific interest is the pulmonary valve since there is limited research on resolving pathologies that affect it. Like the aortic and mitral valves, common pathologies include stenosis, regurgitation, and atresia. Notably, the pulmonary valve requires repair and replacement in pediatric patients and young adults due to congenital disabilities. Even with technological advances in valve replacements, limitations still present themselves for use with younger patients …

Computational Tradespace Exploration, Analysis, And Decision-Making: A Proposed Framework For Organizational Self-Assessment, Julia Daniels

All Theses

The ability to assess technical feasibility, project risk, technical readiness, and realistic performance expectations in early-phase conceptual design is a challenging mission-critical task for large procurement projects. At present, there is not a well-defined framework for evaluating current practices of organizations performing computational trade studies. One such organization is the US Army Ground Vehicle Systems Center (GVSC). When defining requirements and priorities for the next-generation autonomy-enabled ground vehicle system, GVSC is faced with the challenge of an increasingly complex programmatic tradespace due to emerging complexities of ground vehicle systems. This thesis aims to document and evaluate tradespace processes, methods, and …

Soft Robotic Arms For Fall Mitigation: Design, Control And Evaluation, Param Malhotra

All Theses

Most fall mitigation devices present a heavy system that avoid injuries to the user by preventing the impact of a fall. They are dependent on the user capability or on the probability that the user falls in the assumed manner the system was designed for. Often that is not the case, hence this project initiates a novel concept of using soft robotic arms to prevent falls from happening in the first place itself and save the user from any injuries. This thesis describes the prototype and development of a soft continuum robotic backpack system. The system can validate its use …

Rapidly Deployable Structures For Disaster Relief And Military Use, Jayson Leonard

All Theses

Rapidly deployable structures currently play a vital role in the recovery aspect of disaster-stricken areas and the safety of military personnel in hostile zones. More recently there has also been a need for the structures to deal with unforeseen disruptions caused by the COVID pandemic, such as COVID testing centers or backyard pop-up offices. These structures could be used in different environments and serve many other purposes. Along with the structural performance of these shelters, they need to integrate into systems set in place effortlessly. For that reason, four key factors were taken into consideration, namely (1) deployability (how difficult …

Optimizing Crispr/Cas9-Mediated Knockdown Of Angptl3 In Liver Cell Lines And Mouse Hepatocytes, Meredith Reeves

All Theses

Familial hypercholesterolemia (FH) is a genetic condition characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C) that leads to an increased risk of developing cardiac disease early in life (Shah et al., 2020). Current treatments such as statins and PCSK9 inhibitors have helped lower LDL-C levels, however they require repeated administration every 4-6 weeks to remain effective (Raal et al., 2018). Angiopoietin-like 3 (ANGPTL3) is an inhibitor of plasma lipid metabolism that has become a promising molecular target for the treatment of FH. Individuals with non-functional copies of ANGPTL3 demonstrate low levels of plasma LDL-C and triglycerides, indicating a protective …

Sustain Water Conservation Behaviors Using Nonparametric Ranking And Social Marketing, Mahmudur Rahman Aveek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Circulation of water use feedback and conservation messaging are strategies implemented to reduce water demand on a short-term (seasonal) basis. Often considered a less impactful strategy than other tactics such as price increments and usage restrictions, authorities mostly use feedback in informational campaigns with a focus to apprise users about their water use. Such conservation programs have had limited success that has been attributed to the fact that the information provided with the feedback campaigns was generic and did not motivate users enough to sustain their water-saving behaviors. However, the advent of disaggregation technologies that can provide appliance-wise water use …

Geometric Analysis Of Insect Wing Vein Network, Jacob White, Ying Hu, Sangjin Ryu, Seunghee Kim, Haipeng Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

An insect wing consists of a thin membrane supported by a system of veins, and flow of blood through the system of veins is critical for maintaining healthy insect wings. Better understanding of the insect wing vein circulation requires to know how the efficiency of blood flow in an insect wing relates to the geometric shape of the vein. Our investigation of the wing vein network of a dragonfly Anax junius follows the idea of Murray’s law, which is established in the study of efficiency of the vein network and the geometric shape of the vein. Instead of using the …

A Novel Testbed For Evaluation Of Operational Technology Communications Protocols And Their On-Device Implementations, Matthew Boeding

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Operational Technology (OT) and Infrastructure Technology (IT) systems are converging with the rapid addition of centralized remote management in OT systems. Previously air-gapped systems are now interconnected through the internet with application-specific protocols. This has led to systems that had limited access points being remotely accessible. In different OT sectors, legacy protocols previously transmitted over serial communication were updated to allow internet communication with legacy devices. New protocols such as IEC-61850 were also introduced for monitoring of different OT resources. The IEC-61850 standard’s Generic Object Oriented Substation Event (GOOSE) protocol outlines the representation and communication of a variety of different …

Manufacturing And Characterization Of Continuous Nanofiber-Reinforced Composites, Lucas Barry

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fiber-reinforced composite laminates are some of the most advanced structural materials available. However, delamination remains a critical challenge due to its prevalence in structures and ability to cause catastrophic failure. Recently, high-temperature composites are at the forefront of polymer-matrix composites research, but they are prone to microcracking followed by delamination. Nanoreinforcement of interfaces by continuous nanofibers has been proposed earlier at UNL and produced increased interlaminar fracture resistance in conventional advanced composites. However, no studies have yet been conducted on emerging high-temperature composites. Also, there is insufficient information on the translatability of observed modes I and II interlaminar fracture toughness …