Mechanical Engineering Commons^™

Computational Fluid Dynamics Based Optimization Method Applied To Hydrokinetic Turbine Devices, Stuart Glenn Fletcher

Graduate Theses and Dissertations

This thesis presents a computational investigation of optimal kinematic operating parameters governing various hydrokinetic turbines (HKT) systems for the use of power generation within river and tidal environments. Two separate studies are performed. The first study investigates optimal cycle parameters for simple and complex kinematic modes governing the motion of oscillating foil energy harvesters (OFEH). An iterative gradient-ascent optimization method is used to search for local efficiency optima based on an initial set of kinematic parameters. To search the operational space for up to eight degrees of freedom (DOF), a maximin space filling condition was implemented to efficiently compute initial …

Multi-Cater Pack Heat Sealer, Ivan Medina-Zepeda, Laurent Hirakata, Donovan Furtado, Cody Ngan

Mechanical Engineering

The Multi-Cater Pack Heat Sealer was developed to support Achievement House, a non-profit organization that employs adults with intellectual and physical disabilities and is facing increasing demand for sealed cater packs. Existing single-pack sealers limited both throughput and accessibility, which led to the creation of a 3D printed attachment for a 40-inch impulse heat sealer. The attachment allows nine packs to be sealed at the same time and includes a tray-style trapdoor that allows for quick unloading. The need for accessibility and usability guided the design throughout the process. Alignment guides improve placement consistency, and the ergonomic layout accommodates both …

Water Bottle Lid Co Detector, Zeke Bukovansky, Jake Siegel, Jack Wisegarver, Cody Rudman

Mechanical Engineering

This project introduces a portable carbon monoxide detector integrated into a water bottle lid to give users a simple way to stay aware of CO exposure in daily life. The design packages an electrochemical sensor, onboard electronics, and clear visual and audible alerts into a compact form that fits standard bottles. By embedding sensing into an object people already carry, the device offers a practical path toward reducing unrecognized CO risks and improving personal safety.

Enhancing Tribological Performance Of Graphite Coatings Through Spray Deposition And Adhesion-Promoting Polydopamine Underlayers, Adedoyin Ayomide Abe

Graduate Theses and Dissertations

Graphite is a widely studied solid lubricant valued for its low friction and layered structure. However, its application as a durable coating remains constrained by poor adhesion to metal substrates and limited wear resistance under sliding. This dissertation presents a systematic approach to overcoming these limitations by integrating deposition process optimization with surface chemistry modification to develop scalable, high-performance graphite coatings. Unlike many prior studies that focus on polished or idealized surfaces, this work targets steel substrates with elevated roughness levels (Sa ≥ 1 μm), aligning with conditions found in practical engineering components. The first phase of research begins by …

Small Laser-Textured Dimples For Improved Tribological Performance Of Cocrmo In Artificial Hip Joints, William Basore Bennett

Graduate Theses and Dissertations

Total hip replacement is a highly successful surgical intervention that restores mobility and improves quality of life for patients with severe joint degeneration. However, the long-term durability of artificial hip joints remains limited by tribological challenges, particularly wear-related failures that can lead to osteolysis and revision surgeries. In metal-on-polyethylene bearing systems, reducing friction and wear at the interface between cobalt–chromium–molybdenum (CCM) femoral heads and ultra-high molecular weight polyethylene (UHMWPE) liners is critical to extending implant lifespan. Laser surface texturing has emerged as a promising technique to improve tribological performance by introducing micro-dimples that enhance lubricant retention and reduce asperity contact. …

Residential Hvac Installation Faults: Field Prevalence, Drivers, And Energy Impacts, Seyed Ali Rooholghodos

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

Faults in residential comfort systems can have detrimental effects on the performance of the system, reducing the energy efficiency, affecting indoor comfort, and shortening equipment lifespan. Many of the faults occur at installation. However, there has not previously been a systematic and nationally representative study to indicate the prevalence of the faults, meaning the distribution of faults by fault type and fault intensity. Understanding true fault prevalence is essential to be able to identify derivers, and to assess the incremental electricity consumption of the new installation systems.

This study presents on-site data from 341 new central cooling systems—air conditioners and …

Experimental Characterization Of An Additively Manufactured Porous Gyroid Air-Cooled Heat Sink, Grant S. Resler

Mechanical Engineering Undergraduate Honors Theses

This paper presents the development of a ducted test facility designed to evaluate heat sinks efficiency at varying air velocities. This enables the evaluation of both heat transfer and pressure drop performance. These metrics are essential to the overall efficiency of heat sinks and help identify the optimal air velocity to achieve the desired thermal performance. A standard plate fin heat sink was used as a control for comparison to a novel heat sink. The specialized heat sink geometry was generated using nTop, a generative design software focused on additive manufacturing. This design was fabricated via Direct Metal Laser Sintering …

Exploratory Diver Geotechnical Equipment (Edge), Angel Villicana, Merrick Zellers, Erik Heuchert, Lucas Heuchert

Mechanical Engineering

The goal of this report is to showcase how our final Core Sampler design and prototype address the needs of Navy Divers. Geotechnical equipment for Navy divers has not been updated since the early to mid-1980s, resulting in imprecise and outdated sampling methods. The primary purpose of this project is to enhance, modernize, and redesign a tool to collect a minimally disturbed core sample of the seabed for geotechnical evaluation. This report presents the full development of our project from concept to verification and final outcomes. It begins with the statement of disclaimer, followed by a four-panel executive summary and …

Harnessing The Mechanical And Gelation Behavior Of Tyramine-Substituted Silk Fibroin Bioinks Through Integration Into A Modular And Low-Cost 3d Bioprinting Platform, Sourjjadeepta Biswas

Boise State University Theses and Dissertations

3D printing has become an indispensable tool in research labs across the globe. Yet, when it comes to bioprinting with custom or sensitive bioinks, accessible options remain limited. Commercial systems are often prohibitively expensive and restricted to proprietary materials, while DIY setups frequently lack the precision and compatibility needed for biologically relevant printing. Moreover, tunable bioinks that align with real-world biological constraints are still hard to come by. To address these gaps, we developed a modular, low-cost bioprinting platform tailored for tyramine-substituted silk fibroin (TA-SF) hydrogels-biocompatible materials known for their rapid gelation, tunable stiffness, and potential to support cell differentiation …

Mechanical Properties Of Sintered Lunar Regolith Simulant Lhs-1 When Moulded Under Different Temperatures And Time At Constant Pressure, Jasper Stevens

The Plymouth Student Scientist

Humans are returning to the Moon for the first time since 1972. And when they arrive, In-Situ resource Utilisation (ISRU), the philosophy of using local materials and resources will be required to help maintain a more permanent presence on the Moon. Lunar regolith is the homogenous layer of inorganic ‘soil’ that covers nearly the entire Lunar surface, making it the most readily available material for ISRU. This report investigates the effect of changing time and temperature applied to samples of lunar regolith simulant LHS-1 formed as freestanding samples under constant pressure, before sintering into a consolidated sample. Compressive testing on …

Application And Suitability Of Using Paraffin Wax In A Thermal Store For Residential Buildings In The Uk, Cameron Edwards

The Plymouth Student Scientist

Heating costs and pressure to reduce carbon emissions are rapidly increasing. A possible solution is the implementation of efficient energy storage systems for UK residential buildings. Paraffin wax-based thermal energy storage offers a promising solution due to its low-cost, high-energy density, and long-term stability. However, its low thermal conductivity significantly reduces its practicality. Multiple upgrades, such as implementing highly conductive particles and nanotubes, have been previously studied but lack the inclusion of cost-effectiveness and real-world feasibility. This paper reviews current research and develops a numerical model using the Enthalpy method and a 2D finite difference approach, utilised in Python. It …

Boundary-Layer Mechanisms In Flow Over Triangular Porous-Textured Flat Plates: A Computational Fluid Dynamics Study, Luis Angel Alvarez

Theses and Dissertations

Growing demand for energy-efficient vehicles drives research into flow control strategies that mitigate aerodynamic drag. Active devices such as morphing flaps or plasma actuators offer real-time authority but require external power. Passive concepts, including riblets, tubercles, porous coatings, and miniature vortex generators, reshape the boundary layer without additional energy input. We propose an integrated passive solution called Triangular Porous Texturing (TPT). TPT combines the two mechanisms: a periodic array of triangular prisms that generate controlled streamwise vortices, and an embedded porous matrix that locally adjusts pressure gradients near the wall. Acting synergistically, these features attenuate near-wall turbulence, redistribute momentum, and …

Development And Testing Of A Prototype Erbium-Doped Lithium Tantalate Based Sensor For Infrastructure Crack Detection And Measurement, Alejandro Barrera

Theses and Dissertations

Ensuring the safety and longevity of infrastructure is crucial to safeguarding communities and preserving economic stability. In this study, the development of a novel sensor for detecting and characterizing cracks in infrastructure, particularly suited for deployment on Unmanned Aerial Vehicles (UAVs), is presented. The device utilizes a laser (operating at 980 nm) for excitation of erbium-doped lithium tantalate nanoparticles that emit 1550 nm wavelength, which stimulates a photodiode for data collection. The data was utilized to collect, process, and reconstruct topological information. The synthesized lithium tantalate nanoparticle samples vary in erbium doping percentages of 0.5%, 3%, and 10%. Experimental evaluation …

Experimental And Numerical Study On The Influence Of Carbon Fiber Reinforcement On The In-Plane Compressive Properties Of 3d Printed Hexagonal Honeycomb Core Structures, Deon Wallace

All Theses

There is difficulty with numerically replicating the behavior of composite honeycomb core structures numerically due to the trouble of gathering material properties from a hollow structure. Also, complex part geometries and carbon fiber reinforcement strategies can lead to unwanted structural weaknesses and variance in material properties that may not be reflected in numerical analysis when the part is additively manufactured. In this study, edgewise compressive testing is used to characterize the mechanical behavior and performance characteristics of these structures. The experimental results indicate an increase in the Young’s moduli of the honeycomb core structures as carbon fiber concentration increases. However, …

Capillary Imbibition Of Shear-Thinning Xanthan Gum Solutions, Aimee Sayster

All Theses

Capillary rise in confined geometries plays a critical role in numerous natural and industrial processes. While classical models such as the Lucas–Washburn equation accurately describe the dynamics of Newtonian fluids, they fail to capture the complex behavior of shear-thinning, non- Newtonian fluids whose viscosity varies with shear rate. This research investigates the capillary rise dynamics of shear-thinning xanthan gum polymer solutions in capillary tubes. The rheological behavior of each fluid is characterized using the Ellis model, which accounts for shear-thinning effects through three key parameters: zero-shear viscosity μ0, characteristic shear stress τ1/2 and viscosity index α. Experimental data was collected …

Study On The Knock Resistance Offered By Thermally Stratifying Water Injections In A Single Cylinder Spark Ignition Engine, Aditya Datar

All Theses

Stochastic end-gas autoignition in SI engines, commonly called ‘knock’, limits attainable engine efficiencies. Multiple pathways to extend SI engine operation into knock-limited regions have been studied, including direct water injection (DWI). This study employs single-cylinder engine experiments and modeling to investigate the knock resistance offered by compression stroke water injections, which have shown to thermally stratify the cylinder in HCCI. In SI, thermally stratifying injections are expected to forcibly widen the cylinder temperature distribution by preferentially cooling the cylinder periphery. The end-gas is in the cylinder periphery; therefore, a cooler end-gas would result in longer ignition delays, thus providing knock …

Tradespace Exploration For Multiple Collaborative Vehicles, Mrunal Deshmukh

All Theses

Modern military operations demand systems that adapt to uncertain, rapidly changing missions across diverse terrains. Traditional single-platform vehicle design is insufficient for such complexity. This research introduces a hierarchical tradespace exploration framework for designing and evaluating families of heterogeneous ground vehicles under a System-of-Systems (SoS) architecture. The framework treats vehicle design as a co-optimization problem, where a “parent” vehicle (e.g., a Squad Multipurpose Equipment Transport) coordinates specialized “child” vehicles for reconnaissance, amphibious tasks, terrain traversal, and stealth missions. Unlike conventional approaches that optimize vehicles individually, this study emphasizes collaborative performance, resource sharing, and adaptability at the family level. Central to …

Multi-Criteria Decision-Making For Sustainable Design: Stakeholder Prioritization And Methodological Comparison In Solar And E-Bike Applications, Swagath Madhu Gowda

All Theses

This thesis focuses on using Multi-Criteria Decision-Making (MCDM) methods to support sustainable product design by addressing the trade-offs between environmental, economic, and social goals. The research is presented through two studies that demonstrate how both subjective and objective decision-making approaches can guide sustainability evaluations.

The first study applies the Analytic Hierarchy Process (AHP) to assess residential solar panels by incorporating stakeholder perspectives from sustainability experts, end users, and industry professionals. Using Life Cycle Sustainability Assessment (LCSA) data, this study identifies how different stakeholder groups prioritize sustainability criteria and applies Aggregation of Individual Priorities (AIP) to combine their judgments. A one-at-a-time …

Optimal Control Of Human Exercise Using An Individualized Physiological Three-Tank Model And Dynamic Programming, Asal Lotfi

All Theses

This thesis develops a physiologically inspired three-tank model of human bioenergetics to describe and optimize fatigue and recovery during exercise. The aerobic, phosphagen, and glycogen systems are modeled as coupled reservoirs whose states constrain instantaneous power output. Building on this representation, dynamic programming is used to compute pacing strategies that respect physiological limits while maximizing task-specific goals such as peak power or total work over a fixed duration, enabling individualized, goal-driven exercise prescriptions. The three-tank dynamics are formulated in continuous time and then discretized under a zero-order-hold assumption for simulation and optimal control. Model parameters are linked to standard field …

Understanding Policy Transfer Under Decomposition And Coordination: Sequential Reinforcement Learning With Relaxation-Based Feasibility Control, Aannand Lal

All Theses

This thesis investigates how decomposition and coordination (D&C) choices influence exploration, learning, and transfer in reinforcement learning (RL) based design frameworks. A unified methodology is developed to evaluate generality under decomposition and to demonstrate sequential coordination on a representative physical task. The generality study holds the underlying physics constant while varying problem presentation - specifically scalarization weights, objective orientations, and feasibility handling. A train-evaluate matrix is constructed in which each trained policy is assessed across all alternative decompositions. Set-based diagnostics quantify generality through exact-match identity, Jaccard similarity of distinct feasible states, total feasible coverage, and Pareto-front quality. Results show that …