Mechanical Engineering Commons^™

Investigation Of Vapor Deposited Conduction Seed Layer For Electrodeposition On Polymers, Olivia Bray

UNF Graduate Theses and Dissertations

The use of three-dimensional printing (3d printing) technologies are becoming increasingly popular in today’s society due to the time and cost advantages associated with these processes. In industries with a high demand for customizable and one-of-a-kind parts at a low volume, these additive manufacturing processes offer a promising solution. Surgical devices are a great example of this demand. Despite the advantages offered by 3d printing, the mechanical integrity of these 3d printed parts are often not comparable to the solid metal parts that have historically been used. In an effort to create a superior part and reach operational requirements, reinforcement …

Examination Of The Adhesiveness Of The Nanotube Layer On Anodized Commercially Pure Titanium Samples Using The Micro-Limiting Dome Height Test And The Tensile Test., Joshua Manohar Chinthapalli

Graduate Research Theses & Dissertations

Titanium oxide (TiO2) nanotube is one of the most extensively studied nanotubes due to its wide applications in electronics and medical fields. In this study, we used electrochemical anodization to create nanotubes on commercially pure titanium (Cp-Ti) samples and examined the adhesiveness of the nanotube layer on the sample surface. Particularly we conducted micro-limiting dome height (µLDH) tests on anodized Cp-Ti foils of 38 µm thickness and 4 mm diameter at room temperature, 100℃, and 200℃. We also conducted tensile tests on standard tensile specimens of anodized Cp-Ti plate at room temperature, and 200℃. The Hitachi S-4500 Field Emission Scanning …

Surface Modification Of Titanium For Orthopedic And Drug Delivery Applications, Prantik Roy Chowdhury

Graduate Research Theses & Dissertations

Titanium is one of the most attractive metal used in orthopedic and drug delivery applications because of its excellent mechanical properties, biocompatibility and high corrosion resistance. However, due to its bio-inertness, fibrous tissue forms between the bone and implant which causes loosening of implant. Surface modification can play an important role to enhance interaction between implant and the surrounding tissues which reduces the implant failure. The aim of this study is to a) incorporate magnesium (Mg) into modified titanium surface by different deposition methods for bone-implant interaction, b) modify the surface of titanium by alkali treatment, and c) investigate the …

Model-Based Network Reconstruction From Cascade Dynamics, Katherine Irena Chwistek

Graduate Research Theses & Dissertations

Network representation provides a natural framework for the study of real world complex systems. From social networks and animal groups to interneuronal communications and power grid systems, complex patterns of interaction can be captured and modeled using networks in a simple mathematical form. In many cases, however, a faithful network representation of the system is not readily available. For this reason, network reconstruction has become a growing topic of interest in recent years, the goal of which is to discover the hidden interaction patterns among individuals by fitting input-output data from multiple experiments to candidate network topologies.

During a cascade, …

Particle Injection Simulation On Cold Spray Technology, Christopher A. Santini

Electronic Theses and Dissertations

Computational Fluid Dynamics (CFD) is a useful tool when it comes to research in the fields of Aerodynamics, Turbomachinery, and is used in several other fields of research. CFD is an important tool in the engineering industry because it allows for understanding and evaluation of a new design, this can lead to advancements in developing a more efficient and effective design. This tool helps in the understanding of the flow phenomena and how it can interact with its surroundings. One of the main reasons in the use of CFD is to reduce the cost of testing a design by running …

Finding A Single Equation To Represent Urea Evaporation, Sublimation, And Decomposition In Selective Catalytic Reduction Systems, Noah Hertzler

Senior Honors Theses

Aqueous Urea used in Selective Catalytic Reduction (SCR) Systems undergoes three sequential processes that result in ammonia being produced to reduce harmful NOx emissions: Water evaporation, Urea sublimation, and Urea decomposition into ammonia and isocyanic acid. While these phases can be simplified by modeling the Urea as pure water, accuracy is sacrificed to do so. In order to make SCR modelling both accurate and simple, this project set out to find an equation that could represent all three processes. Simulations were run in ANSYS and Particle to generate a set of data, then an empirical equation was created to model …

Modeling And Characterization Of A Pull-In Free Mems Microphone, Mehmet Ozdogan, Shahrzad Towfighian, Ronald Miles

Mechanical Engineering Faculty Scholarship

In this study, we examine the feasibility of designing a MEMS microphone employing a levitation based electrode configuration. This electrode scheme enables capacitive MEMS sensors that could work for large bias voltages without pullin failure. Our experiments and simulations indicate that it is possible to create robust sensors properly working at high DC voltages, which is not feasible for most of the conventional parallel plate electrode-based micro-scale devices. In addition, the use of larger bias voltages will improve signal-to-noise ratios in MEMS sensors because it increases the signal relative to the noise in read-out circuits. This study presents the design, …

Lateral Pull-In Instability Of Electrostatic Mems Transducers Employing Repulsive Force, Meysam Daeichin, Ronald Miles, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

We report on the lateral pull-in in capacitive MEMS transducers that employ a repulsive electrostatic force. The moving element in this system undergoes motion in two dimensions. A two degree-offreedom mathematical model is developed to investigate the pull-in quantitatively. The nonlinear electrostatic force, which is a vector function of two spatial coordinates, is determined by calculating the potential energy of the system using a boundary element approach. The equilibrium points are found by numerically solving the nonlinear coupled static equations. A stability analysis reveals that depending on the values of the lateral and transverse stiness, the system undergoes dierent bifurcations …

An Extensive Set Of Kinematic And Kinetic Data For Individuals With Intact Limbs And Transfemoral Prosthesis Users, Seyed Abolfazl Fakoorian, Arash Roshanineshat, Poya Khalaf, Vahid Azimi, Daniel J. Simon, Elizabeth Hardin

Electrical and Computer Engineering Faculty Publications

This paper introduces an extensive human motion data set for typical activities of daily living. These data are crucial for the design and control of prosthetic devices for transfemoral prosthesis users. This data set was collected from seven individuals, including five individuals with intact limbs and two transfemoral prosthesis users. These data include the following types of movements: (1) walking at three different speeds; (2) walking up and down a 5-degree ramp; (3) stepping up and down; (4) sitting down and standing up. We provide full-body marker trajectories and ground reaction forces (GRFs) as well as joint angles, joint velocities, …

Comparative Evaluation Of Carbon Reinforced Polyetherketone Acetabular Cup Using Finite Element Analysis, A. Abdal, Rafiqul Noorani, G. Cha

Mechanical Engineering Faculty Works

Background: Patients suffering from osteoarthritis undergo surgery to replace hip joints with hip prosthesis implants. Today most acetabular cups of hip prostheses are made of Ultra-High-Molecular-Weight-Polyethylene. However, these materials acting as acetabular cups of the implant have been recalled since patients have been feeling uncomfortable and abstained from physical activities. A newly introduced material, 30% Carbon Reinforced Polyetherketone, possess better isotropic mechanical properties and lower wear rates.

Objective: The research aims to compare the von-Mises stresses and deformation in static and dynamic loading of Ultra-High Molecular-Weight-Polyethylene to 30% Reinforced Carbon Fiber Polyetherketone using Finite Element Analysis.

Material and Methods: An …

High Tech, High Risk: Tech Ethics Lessons For The Covid-19 Pandemic Response, Emanuel Moss, Jacob Metcalf

Publications and Research

The COVID-19 pandemic has, in a matter of a few short months, drastically reshaped society around the world. Because of the growing perception of machine learning as a technology capable of addressing large problems at scale, machine learning applications have been seen as desirable interventions in mitigating the risks of the pandemic disease. However, machine learning, like many tools of technocratic governance, is deeply implicated in the social production and distribution of risk and the role of machine learning in the production of risk must be considered as engineers and other technologists develop tools for the current crisis. This paper …

Development Of Bio-Based 2t Engine Oil In Marine Engine Application / Babooraman Shanmuganathan, Babooraman Shanmuganathan

Student Works (2020-2029)

Two-storke enginers are simple and lightweight two-cycle spark ignition engine with no oil sump is needed. The use of bio-based lubricants was analyzed to replace commercial mineral and synthetic-based lubricants. Lubricants were prepared by mixing three components of oil which comprise of base oil, additives, and solvent. In this research, four samples of base oil had been prepared with a different weight ratio of the PFAD-NPGester and Type II mineral. Then each of the simples were added with a similiar weight ratio of additives and solvent. A commercial lubricant was used as areference lubricant to be compared with samples prepared. …

Experimental And Computational Characterization Of Sodium Nitrate @ Silica Nano Capsules For Thermal Energy Storage Applications, Wataru Hashimoto

Graduate Research Theses & Dissertations

In this investigation, a nanocapsule composed of a sodium nitrate core and a silicon dioxide shell is synthesized, characterized, and analyzed utilizing a mixture of analytical and computational tools. The sol-gel method was selected as the process of nanoencapsulation. Analytical characterization techniques employed in this investigation include differential scanning calorimetry (DSC) to measure melting temperatures and enthalpies of fusion, dynamic light scattering (DLS) to calculate particle size distributions, scanning electron microscopy (SEM) to analyze surface characteristics, transmission electron microscopy (TEM) to perform shell characterization, and energy dispersive X-ray spectroscopy (EDS) to determine chemical composition. Preliminary results indicated a decrease in …

Transportation Analysis And Related Design Optimization Of The Fermilab High-Beta 650 Mhz Cryomodule, Josh F. Helsper

Graduate Research Theses & Dissertations

The Proton Improvement Plan-II (PIP-II) at Fermi National Accelerator Laboratory(FNAL) will create a new and vastly improved accelerator, which will be the source of high energy particles for the experiments taking place at FNAL. The new linear accelerator (LINAC) contains several types of cryomodules, which are individual particle accelerators. The last cryomodule in the LINAC will be the High-Beta 650 (HB650), which will operate at 650 MHz. Each module is approximately 15 meters in length, 1.5 meters wide, weighs 13 tonnes, and shares many design features with three of the other cryomodules. The HB650 consists of two primary sections, the …

Laminate-Like Behavior Of An Additively Manufactured Polymer With Underlying Bioinspired Architecture, Flavio Jonuzaj

Graduate Research Theses & Dissertations

Laminates are a class of composite materials in which several unidirectional laminae are stacked together to create a material with a clear layer-by-layer architecture. Traditionally, each lamina is itself a composite consisting of aligned fibers, such as cellulose, graphite, or glass, embedded within a polymer, ceramic, or metal host matrix. These materials are unique in the sense that their engineering properties can be greatly varied simply by changing the stacking order of lamina within the laminate. While there are several traditional manufacturing approaches for laminates, recent research has focused on assessing the feasibility of using additive manufacturing techniques to create …

Micro-Macro Mathematical Modeling Analysis Of An Al-Air Battery, Christopher Charles Welch

Graduate Research Theses & Dissertations

The aluminum-air battery is a very promising electrical energy storage system for portable electronics and electric vehicles because it is safe, inexpensive, and has a very high energy density. With the [EMIm]Cl-AlCl3 room-temperature ionic liquid (RTIL) electrolyte, by controlling the acidity, H2 evolution and dendrite formation are prevented and the Al2O3 passive film on the anode can be partially dissolved (cracked), so the battery’s lifespan is extended and even allows battery charging. Still, the Al2O3 passive film on the anode and Al2O3 deposition on the cathode remain issues which negatively affect battery performance. While these phenomena have been experimentally observed, …

Implementation Of A 2d Bond Based Peridynamic Fatigue Model In Fem, Kyle Mansfield

Graduate Research Theses & Dissertations

A relatively new fracture theory known as peridynamics has been developed which uses a nonlocal theory to describe crack growth, resolving many of the issues associated to the classical continuum theory. Internal material interactions are described via a family of ‘bonds’, capable of exerting force over a macro-scale region of influence known as the horizon. Bond damage accumulates naturally due to repeated cyclic or critical loading and damage precipitates as a growing crack as bonds reach a critical damage and are severed. In the present work a modified compact tension specimen subjected to cyclic loading is modeled with the 2D …

Molecular Dynamic Simulations Of Mechanical Properties In Nb-Nbc Core-Shell Nanowires And Nodes, Austin Pauga

Graduate Research Theses & Dissertations

Nanoporous materials have attracted attention recently because of their extensive range of possible applications. These nanoporous materials are comprised of nanowires and nodes. A node joins three or more nanowires of different orientations. Current research has focused on nanowires and nodes composed of metallic single crystals and core-shells. Nanoporous materials experience brittle failure from the rupture of the weakest feature, overloading the other remaining structural features. To alter the deformation behavior of the network nodes, a ceramic layer has been added around the metal. Coating the metallic ligaments with ceramic shell increases the buckling capacity of each ligament and further …

In-Situ Optoelectronic Powder Flow Measurement Analysis For Directed Energy Deposition Applications, Mark Sliwka

Graduate Research Theses & Dissertations

Directed energy deposition (DED) is a metal additive manufacturing method of creating parts by using a high-power laser to fuse powdered metals into fully dense three-dimensional structures. To ensure the geometric and mechanical integrity of the completed part, the powder flow rate of the DED system must be accurate and repeatable for manufacturability. Due to its opacity and reflectivity, one method of measuring powder flow is by utilizing an optoelectronic sensor. The sensor consists of a diode laser with a line generator that emits a thin defocused light sheet, a photodiode, and a set of lenses. The corresponding lens collimates …

Thermal / Structural Analysis Of The Hb 650 Thermal Shield, Gerald J. Smith

Graduate Research Theses & Dissertations

Fermilab’s PIP-II project’s superconducting linear accelerator (Linac) will drive the next generation of particle accelerators through a revolution in beam intensity. Key to beam intensification are the high efficiencies of niobium-tin superconducting radiofrequency (SRF) cavities operating at cryogenic temperatures near 5 Kelvin. A multifaceted approach is employed to achieve and maintain the extreme temperature. Vacuum provides the first barrier to thermal convection. Physical thermal intercept zones further isolate the exterior shell vacuum vessel at 300 Kelvin from the supercooled beamline. The first thermal intercept lies just inside the exterior vacuum vessel forming the 40 Kelvin zone. This 40K thermal shield …

Numerical Investigation Of Darrieus Wind Turbine With Slotted Airfoil Blades, Ahmed Elbaz, Omar Sherif Mohamaed, Ahmed Abdelhamid Ibrahim, Ahmed Khaled Etman, Amr A. Abdelfattah

Mechanical Engineering

Low starting torque is considered as one of the major drawbacks of Darrieus type vertical axis wind turbine (VAWT). Design optimization to overcome this problem by modifying the airfoil geometry has received great attention by the wind energy community. Moreover, efforts have been directed towards augmenting the power coefficient of the turbine. In the present work, the effect of employing slotted airfoil as turbine blade on the performance and starting characteristics has been investigated. The slot parameters; slot location, angle of inclination, and dimensions, were optimized for NACA 0018 airfoil which is commonly used in Darrieus turbines. The flow over …

Binder Saturation, Layer Thickness, Drying Time And Their Effects On Dimensional Tolerance And Density Of Cobalt Chrome - Tricalcium Phosphate Biocomposite, John Ruprecht

All Graduate Theses, Dissertations, and Other Capstone Projects

Traditional metals such as stainless steel, titanium and cobalt chrome are used in biomedical applications (implants, scaffolds, etc.) but suffer from issues such as osseointegration and compatibility with existing bone. One way to improve traditional biomaterials is to incorporate ceramics with these metals so that their mechanical properties can be similar to cortical bones. Tricalcium phosphate is such a ceramic with properties such that it can be used in the human body. This research explores the use of the Binder Jetting based additive manufacturing process to create a novel biocomposite made of cobalt chrome and tricalcium phosphate. Experiments were conducted …

A Framework For A Successful Additive Repair System, Todd E. Sparks

Doctoral Dissertations

“The goal of this research is to generate a revolutionary improvement to the usability and usefulness of additive repair technology by integrating a set of tools into a seamless work flow. Insufficient automation in the current repair process is a huge hurdle in achieving cost-effective, reliable repairs. Many opportunities have been missed due to inconsistency, quality issues and lack of robustness and flexibility. The present work addresses deficiencies in preparatory steps such as 2D and 3D geometry processing, parameter estimation, and path planning as well as on-machine execution of the path plan. The bulk of the effort is focused on …

Magnetic Control Of Transport Of Particles And Droplets In Low Reynolds Number Shear Flows, Jie Zhang

Doctoral Dissertations

“Magnetic particles and droplets have been used in a wide range applications including biomedicine, biological analysis and chemical reaction. The manipulation of magnetic microparticles or microdroplets in microscale fluid environments is one of the most critical processes in the systems and platforms based on microfluidic technology. The conventional methods are based on magnetic forces to manipulate magnetic particles or droplets in a viscous fluid.

In contrast to conventional magnetic separation method, several recent experimental and theoretical studies have demonstrated a different way to manipulate magnetic non-spherical particles by using a uniform magnetic field in the microchannel. However, the fundamental mechanism …

Combustion And Emission Characteristics Of Ic Engines Fueled By Hydrogen And Hydrogen/Diesel Mixtures And Multi-Objective Optimization Of Operating Parameters, Abdulhakim Issa Jabbr

Doctoral Dissertations

“The present study considers combustion of hydrogen in IC engines. In general, the work focuses on simulating the engine performance and emissions at different operation parameters, and using optimization techniques. Task I work deals with the engine performance and emissions of a single cylinder spark-ignition (SI) engine fueled by hydrogen. The engine was simulated at different equivalence ratios, exhaust gas recirculation (EGR) and ignition timing. The results indicate that NOx emissions, engine power, and efficiency are reduced by increasing EGR level, and increased with increasing equivalence ratio and advanced ignition timing. The best operating conditions for hydrogen engines were obtained …

Development Of Horizontal Axis Hydrokinetic Turbine Using Experimental And Numerical Approaches, Abdulaziz Abutunis

Doctoral Dissertations

“Hydrokinetic energy conversion systems (HECSs) are emerging as viable solutions for harnessing the kinetic energy in river streams and tidal currents due to their low operating head and flexible mobility. This study is focused on the experimental and numerical aspects of developing an axial HECS for applications with low head ranges and limited operational space. In Part I, blade element momentum (BEM) and neural network (NN) models were developed and coupled to overcome the BEM’s inherent convergence issues which hinder the blade design process. The NNs were also used as a multivariate interpolation tool to estimate the blade hydrodynamic characteristics …

Additive Manufacturing Of Customized Lithium-Ion Batteries: Process Fundamentals And Applications, Xiaowei Yu

Doctoral Dissertations

“In the pasting decades, considerable efforts have been spent in developing the next-generation lithium-ion batteries (LIBs), from advanced active materials to new manufacturing methods. The development of additive manufacturing (AM) has brought new opportunities to LIBs. In this work, two AM methods are introduced for fabricating electrodes of LIBs. The first method is aerosol printing, which is a solvent-based wet additive method. Whereas the second method is a solvent-free, dry printing method. The commonly used materials for current collectors and active materials (including cathodes and anodes) of LIBs are aerosol printed and the electrochemical functionalities of the printed materials are …

Fabrication And Characterization Of Multifunctional Composites, Aditya R. Thakur

Doctoral Dissertations

“This study details the research to facilitate fabrication and characterization of novel structural composites reinforced with carbon fibers. Across industries, materials with high performance-to-weight ratio are sought after. Using carbon fibers as secondary phases in these proposed composites, specific characteristics can be tailored in these materials to manufacture strong, lightweight, high performance structures. The first part of the research focused on the improvement in the mechanical properties of the composites using carbon fiber reinforcement. As a part of this study, toughened ceramic composites with predictable failure patterns were produced using carbon fiber inclusions. A closed-form analytical model was developed to …

Observer-Based Event-Triggered And Set-Theoretic Neuro-Adaptive Controls For Constrained Uncertain Systems, Abdul Ghafoor

Doctoral Dissertations

"In this study, several new observer-based event-triggered and set-theoretic control schemes are presented to advance the state of the art in neuro-adaptive controls. In the first part, six new event-triggered neuro-adaptive control (ETNAC) schemes are presented for uncertain linear systems. These comprehensive designs offer flexibility to choose a design depending upon system performance requirements. Stability proofs for each scheme are presented and their performance is analyzed using benchmark examples. In the second part, the scope of the ETNAC is extended to uncertain nonlinear systems. It is applied to a case of precision formation flight of the microsatellites at the Sun-Earth/Moon …

Characterization And Recyclability Of 304l Stainless Steel Powder For Use In The Selective Laser Melting Process, Austin Taylor Sutton

Doctoral Dissertations

"Powder-bed fusion refers to a subset of additive manufacturing (AM) methods which successively melts and solidifies selected regions within a powder bed on a layer-by-layer basis to construct components directly from computer-aided design files. Laser Powder-Bed Fusion (L-PBF) is a process among the powder-bed fusion techniques that utilizes a laser to consolidate particles into a material with little porosity. During the L-PBF process, the large energy input from the laser causes the production of ejecta in the form of laser spatter and condensate, both of which have the potential to settle in the surrounding powder bed compromising its reusability. In …