Engineering Commons^™

Formulation Of Uv Curable Resins Utilized In Vat Photo Polymerization For The Additive Manufacturing Of Gun Propulsion Charge In 3d Printers, David T. Bird

Theses

Formulating resins for Additive Manufacturing (AM), utilizing UV laser stereolithography, is a new technique that makes it possible for the fabrication of complex geometries with high dimensional resolution. This layer by layer photopolymerization approach spans various industrial sectors from adhesives, inks and optical fibers to nanotechnology and biomaterials. UV curable resins such as epoxides, vinyl ethers and other acrylates are important monomers that offer effective mediums for energetic materials, and the potential exists to develop environmentally friendly formulations with suspended energetic materials at various solids loading levels.

Developing techniques for UV curing formulations of highly loaded energetic suspensions is a …

Electrical Properties Of Metal/Wse2structures, Zeel Rajiv Gandhi

Theses

The formation of low resistance metal contacts on two-Dimensional layer (2-D) of WSe2 is a big challenge. In this research, a comparative study is presented on the electrical properties of metal/WSe2 Schottky barrier diodes with various metals such as Au, In, Al, and Ga in the temperature range of 80K to 400K well within the domain of thermionic emission theory.

Topics covered here include the factors that determine the Schottky barrier height, the device capacitance, and its current-voltage (I-V) characteristics. I-V curves for different metals on WSe2 are analyzed as function of temperature. Barrier height is determined from Au-nWSe2 Schottky …

Microstructure And Mechanical Properties Of Additive Manufacturing Titanium Alloys After Thermal Processing, Ahmet Alptug Tanrikulu

Dissertations and Theses

Titanium alloys are widely used for aerospace and biomaterial applications since their high specific strength, and high corrosion resistivity. Besides these properties, titanium is an excellent biocompatible material widely used for internal body implants. Because the products have complex geometries in both applications, Additive Manufacturing (AM) methods have been recently applied for production. AM methods can process a direct 3-D shape of the final product, decrease total production time and cost. However, high residual stress of the final product limits the application of AM components, especially the ones that are exposed to cyclic loading. In the present study, the initial …

Investigation Of 2195 And 2219 Post Weld Heat Treatments For Additive Friction Stir Lap Welds, Matthew Champagne

University of New Orleans Theses and Dissertations

To evaluate potential uses for friction stir welding in additive manufacturing, two separate parts were fabricated, one of 2195-T84 and the other 2219-T87, utilizing fixed pin techniques and additive lap welds. The parts were cut into samples, artificially aged and subjected to Rockwell hardness (HRB), Vickers hardness, micrographic photography, and metallographic imaging on both pre- and post- heat treatment. Additionally, tensile testing was performed on the heat-treated samples. A comparisons of test results showed a minimal increase in the yield strength of the 2195-T84 samples compared to as-welded tensile results obtained from a previous project. The ultimate tensile strength was …

Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles, Jose Enrique Rubio

University of New Orleans Theses and Dissertations

The exceptional flying characteristics of airborne insects motivates the design of biomimetic wing structures that can exhibit a similar structural dynamic behavior. For this purpose, this investigation describes a method for both manufacturing a biomimetic insect-sized wing using the photolithography technique and analyzing its structural dynamic response. The geometry of a crane fly forewing (family Tipulidae) is acquired using a micro-computed tomography scanner. A computer-aided design model is generated from the measurements of the reconstructed scanned model of the insect wing to design the photomasks of the membrane and the venation network required for the photolithography procedure. A composite …

Adaption Of Catechol And Reversible Addition-Fragmentation Chain-Transfer (Raft) Chemistries For Water-Based Applications, Olabode Oyeneye

Electronic Thesis and Dissertation Repository

Incorporating the binding chemistry of catechol functionality with RAFT chemistry offers a facile and simplified approach for developing a suite of new 2D and 3D hybrid materials with tailored morphologies. Leveraging both chemistries by synthesizing catechol-end functionalized RAFT agents and catechol-containing monomeric species for RAFT (co)polymerization, this dissertation examined a new series of advanced materials that were designed for water-based applications including model flocculants, thermoresponsive hydrogels, adsorbents and underwater adhesives.

To prepare the RAFT agents, novel trithiocarbonates with several catechol end R groups (as postpolymerization anchors) were synthesized that differ in their carbonyl α-substituents (Dopa-CTAs). These materials were evaluated for …

The Processing And Polarization Reversal Dynamics Of Thin Film Poly(Vinylidene) Fluoride, Noel Mayur Dawson

Nanoscience and Microsystems ETDs

Many ferroelectric devices benefit from the ability to deposit thin ferroelectric layers. Poly(vinylidene) fluoride (PVDF) is the prototypical ferroelectric polymer, but processing of thin film ferroelectric PVDF remains a challenge due to the formation of large voids in the film during traditional thin film processing. The research described in this dissertation starts by investigating the origin of these voids. The cause of these voids is found to be caused by vapor induced phase separation (VIPS). Guided by the thermodynamics of VIPS, a process is then designed to produce void-free ferroelectric PVDF thin films on polar and non-polar substrates. The films …

Spray-Dried Cellulose Nanofibril-Reinforced Polypropylene Composites For Extrusion-Based Additive Manufacturing, Lu Wang

Electronic Theses and Dissertations

Compared to conventional manufacturing process, additive manufacturing (AM) offers free-form design, lighter and more ergonomic products, short lead time and less waste. Extrusion-based AM can be used to print thermoplastics. However, extrusion-based AM has processing challenges in printing semi-crystalline thermoplastics, for instance, polypropylene (PP). Cellulose nanofibrils (CNF) are one type of cellulose nanofibers that are produced from pulp fibers. CNF has extraordinary properties which make it an ideal candidate to reinforce polymers. Spray-dried CNF (SDCNF) is able to be incorporated into thermoplastic matrices without modifying conventional processing procedures.

The mechanical properties of 3D printed plastic parts have been considered significantly …

Characterization And Modeling Of Asphalt Concrete For Dynamic Properties And Performances, A S M A. Rahman

Civil Engineering ETDs

The recently developed mechanistic-empirical pavement design guide (MEPDG, also known as Pavement M-E design method) uses the nationally calibrated, binder viscosity-based dynamic modulus predictive model for the design and analysis of asphalt pavements. In this study, this model is assessed for its appropriateness for asphalt-aggregate mixtures typically used in New Mexico. In essence, this study investigates the predictability issue of complex modulus of New Mexico mixes. A total of 54 Superpave mixes with different aggregate gradations, air voids, and binder grades were collected from the mixing plants and from the pavement construction sites. The loose asphalt mixtures were then compacted, …

Functional Bio-Nano Hybrids Through A Precise Control Of Interfacial Interactions At The Nanoscale, Sirimuvva Tadepalli

McKelvey School of Engineering Theses & Dissertations

During the course of evolution, proteins have evolved to perform exquisite functions including structural support, signal transduction, actuation, sensing, catalysis, trafficking, gating, light-harvesting, charge transfer, molecular recognition, self-assembly, self-organization, or combinations of two or more of these functions. A precise control and manipulation of the structure and function of proteins is conceivable with the advent of nanotechnology, which has facilitated the integration of nanomaterials with functional biomolecules to realize bio-nano hybrids with synergistically enhanced functionalities.

At the genesis of bionanotechnology, a paucity in the fundamental understanding of the bio-nano interfaces is a grave impediment to the progress of the field. …

The Inter-Laminar Shearing Effect On Wrinkle Development In Composite Forming Processes, David Sundquist

McKelvey School of Engineering Theses & Dissertations

Composite materials are becoming prevalent in aerospace industries as the uniqueness of the composite structure allows the composite to be tailored specifically for individual applications. Many fabrication techniques produce defects in composite parts such as wrinkles, fiber waviness, fiber misalignment, and porosity. The driving mechanisms behind these defects occurring during forming processes are not fully understood and, thus, characterization formation of these defects in a uncured state is beneficial to optimize composite processing. This work primarily investigated the influence of how uncured pre-impregnated carbon ply properties affect the wrinkling behavior of a composite laminates. Several factors affecting composite ply forming …

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Cellulose Nanofiber-Reinforced Impact Modified Polypropylene: Assessing Material Properties From Fused Layer Modeling And Injection Molding Processing, Jordan Elliott Sanders

Electronic Theses and Dissertations

The purpose of this research was to investigate the use of cellulose nanofibers (CNF) compounded into an impact modified polypropylene (IMPP) matrix. A IMPP was used because it shrinks less than a PP homopolymer during FLM processing. An assessment of material properties from fused layer modeling (FLM), an additive manufacturing (AM) method, and injection molding (IM) was conducted. Results showed that material property measurements in neat PP were statistically similar between IM and FLM for density, strain at yield and flexural stiffness. Additionally, PP plus the coupling agent maleic anhydride (MA) showed statistically similar results in comparison of IM and …

Heterogeneous Anisotropy Index And Scaling In Multiphase Random Polycrystals, Muhammad Ridwan Murshed

Theses and Dissertations

Under consideration is the finite-size scaling of elastic properties in single and two-phase random polycrystals with individual grains belonging to any crystal class (from cubic to triclinic). These polycrystals are generated by Voronoi tessellations with varying grain sizes and volume fractions. By employing variational principles in elasticity, we introduce the notion of a 'Heterogeneous Anisotropy Index' and investigate its role in the scaling of elastic properties at finite mesoscales. The index turns out to be a function of 43 variables, 21 independent components for each phase and the volume fraction of either phase. Furthermore, the relationship between Heterogeneous Anisotropy Index …

Novel Fission Track Detection For Identification And Characterization Of Special Nuclear Materials, Jonathan Allen Gill

Doctoral Dissertations

Fission track detection and analysis is used primarily in nuclear safeguards to identify special nuclear material. Identification of isotopic ratios is a crucial step in understanding the intended use of nuclear material and the nature of the materials production cycle. Unfortunately, this methodology uses etchable track detectors that require significant expertise and intensive labor to process.

This study developed a novel method using lithium fluoride (LiF) as a fluorescing nuclear track detector to conduct fission track analysis for isotopic prediction of uranium enrichment. Individual latent tracks produced by fission products were observed in LiF for the first time. These tracks …

Development Of High-Performing Polydimethylsiloxane-Based Membranes For Carbon Dioxide Separation, Tao Hong

Doctoral Dissertations

Membrane separation is highlighted as one of the most promising approaches to mitigate the excessive CO₂ [carbon dioxide] emission, due to its significant reduction of energy cost compared with many conventional separation techniques. Unfortunately, the separation performance of current membranes does not meet the practical CO₂/N₂ [nitrogen] separation requirements. And due to the huge volume of industrial flue gas, membranes with exceptionally high permeability are needed for practical reasons.

Currently, the separation mechanism of most polymeric membranes is based on size-sieving. However, this method is not sufficient for CO₂/N₂ separations due to the …

Low Energy Recoil Simulations In Mgo, Linbo3, And Litao3 Using Ab Initio Molecular Dynamics, Benjamin Aaron Petersen

Doctoral Dissertations

Ab initio molecular dynamics (AIMD) was utilized to test a series of materials, MgO, LiNbO₃ , and LiTaO₃ , to determine defect structures produced due to low energy recoil events . The kinetic energy required to displace an atom from its lattice site, the threshold displacement energy, was calculated for an array of directions in each material, based on symmetry and complexity of the structure. MgO having a simple rock salt structure provided a model material for demonstrating computational techniques used later on LiTaO₃ and LiNbO₃ . The minimum values for displacing an atom were at …

Mechanical Behavior Of Pipeline Steels And An Al0.1cocrfeni High-Entropy Alloy, Bilin Chen

Doctoral Dissertations

This dissertation is composed of two parts. The first part focuses on the mechanical behavior study on pipelines steels. More specifically, the effect of hydrogen on the deformation behavior of the crack tip of an X52 pipeline steel specimen, and the overload effects on the fatigue crack growth of an x70 pipeline weld metal are discussed. For the second part of the dissertation, fatigue behavior of an Al0.1CoCrFeNi high-entropy alloy (HEA) is studied, and the influence of heat treatment is discussed.

The objectives of the first part of this proposed work are to (1) detect the influence of hydrogen on …

Transport Of Water And Ions Through Single-Walled Armchair Carbon Nanotubes: A Molecular Dynamics Study, Michelle Patricia Aranha

Doctoral Dissertations

The narrow hydrophobic interior of a carbon nanotube (CNT) poses a barrier to the transport of water and ions, and yet, unexpectedly, numerous experimental and simulation studies have confirmed fast water transport rates comparable to those seen in biological aquaporin channels. These outstanding features of high water permeability and high solute rejection of even dissolved ions that would typically require a lot of energy for separation in commercial processes makes carbon nanotubes an exciting candidate for desalination membranes. Extending ion exclusion beyond simple mechanical sieving by the inclusion of electrostatics via added functionality to the nanotube bears promise to not …

Usa Boccia Ball Ramp For Athletes With Quadriplegia, Alissa A. Koukourikos, Matthew Lee, Nathan Bernards

Mechanical Engineering

In this report, the design process in creating an assistive device for Boccia Classification 3 (BC3) players is outlined. The initial research steps, including research into the rules of the game, capabilities of the players, and existing products is documented to show where ideas for the product stemmed from. This transitions into requirements that the sponsor requested, and preliminary designs and ideas for the product. Finally, this report explains the details of the final design, which has been analyzed for safety, ease of use, and ability to function under different conditions. The processes of manufacturing and testing will also be …

Material Properties Design Using Simulations And Experiments For Powder Injection Molding Of Lead Zirconate Titanate (Pzt)., Bhushan Pramod Bandiwadekar

Electronic Theses and Dissertations

Powder injection molding (PIM) process simulations can be performed to minimize the number of injection molding experiments by estimating material properties necessary for PIM simulations. In current work, lead zirconate titanate (PZT) powder-polymer binder feedstock was compounded for 45 vol. % and 52 vol. % solids loading. PIM experiments on designed micro-pillar array geometry were performed using 52 vol. % PZT. Using PIM experiments results as basis, PIM simulations were performed on designed micro-pillar array geometries to understand the effectiveness of PIM simulations with the use of estimated feedstock properties in predicting molding behavior that have micro-features. Additionally, PIM simulations …

Effects Of Electrolyte Formulation On Graphite Anode For Wide Temperature Application, Jeremy Chang

Theses and Dissertations

In this study, we demonstrate that the low temperature power capability of a Li-ion battery can be substantially improved not by adding exotic additives into the electrolyte, but by rational design of the composition of the most commonly used solvents. Through the detailed analysis with electrochemical impedance spectroscopy, the formation of a homogenous solid electrolyte interphase (SEI) layer on the carbon anode surface is critical to ensure the performance of a Li-ion battery in a wide temperature range. Subsequent post mortem analysis after cycling of the negative electrode by XPS revealed that all the electrolyte compositions form similar compounds in …

Synthesis And Characterization Of Glycidyl Methacrylate-Based Graft Copolymer Functional Interfaces, Nikolay Brordinov

All Dissertations

Modification of materials properties such as surface energy, wettability, ability to absorb, contain or release specific type of chemicals enables practical application of these materials in various scientific and engineering set-ups. However, designing protocol that could be easily adapted for different situations and simultaneously unlock multiple variations of the resulting properties is a non-trivial task. This dissertation is devoted to application of glycidyl methacrylate-based graft copolymers for the purposes of surface modification, establishing fundamental trends and dependencies of this process and exploring the possible range of applications. These materials have extremely valuable property to undergo controllable post-synthetic modifications including surface …

Modeling And Simulation Of Iii-Nitride-Based Solar Cells Using Nextnano®, Malak Refaei

Graduate Theses and Dissertations

Nextnano³ software is a well-known package for simulating semiconductor band-structures at the nanoscale and predicting the general electronic structure. In this work, it is further demonstrated as a viable tool for the simulation of III-nitride solar cells. In order to prove this feasibility, the generally accepted solar cell simulation package, PC1D, was chosen for comparison. To critique the results from both PC1D and Nextnano3, the fundamental drift-diffusion equations were used to calculate the performance of a simple p-n homojunction solar cell device analytically. Silicon was picked as the material for this comparison between the outputs of the two simulators as …

Studies On Stable Crack Growth, Mohammed Juma Humaid Al-Ghafri

Theses

The goal of this work is to experimentally investigate the stable crack growth (SCG) fracture behavior of AISI 4340 alloy steel. A series of mode I and mixed mode SCG fracture tests were carried out on 8 mm thick compact tension (CT) specimens subjected to quasistatic loading. The wire cutting technique was used to introduce a pre-notch/ pre-crack of 0.05 mm root radius to the specimen. Five different loading angles Ψ between the loading axis and the crack surface were employed; 90° (mode I), 75°, 65°, 60° and 50°. Five different ratios of original crack length to specimen width a …

Surface Alloying Of Plain-Carbon Steels During The Casting Manufacturing Process, Michael Beining

Theses and Dissertations

At times, the surface properties of an engineered component must be improved or enhanced when compared to the bulk of the component. Thus, various methods of surface alloying, one of the most important surface engineering processes, have been studied and developed for the decades. This study is concerned with the modification of the surface of WCB plain-carbon steel to improve corrosion and wear resistance of components used in the fresh water industry. The objective is to create a corrosion and wear resistant surface on an engineered component by enriching the surfaces with nickel or nickel and chromium, while the bulk …

Real-Time, Selective Detection Of Heavy Metal Ions In Water Using 2d Nanomaterials-Based Field-Effect Transistors, Guihua Zhou

Theses and Dissertations

Excessive intake of heavy metals damages the central nervous system and causes brain and blood disorders in mammals. Heavy metal contamination is commonly associated with exposure to mercury, lead, arsenic, and cadmium (arsenic is a metalloid, but classified as a heavy metal). Traditional methods to detect heavy metal ions include graphite furnace atomic absorption spectroscopy (GFAAS), inductively-coupled plasma optical emission spectroscopy (ICP-OES), and inductively-coupled plasma mass spectroscopy (ICP-MS). Recently, many new methods have been proposed to detect heavy metal ions, including atomic absorption spectrometry, fluorescent sensors, colorimetric sensors, electrochemical sensors, X-ray absorption fine structure spectroscopy, ultrasensitive dynamic light scatting assays, …

A Study Of Manganese And Cobalt Incorporated Nickel Oxide Based Core-Shell Magnetic Nanoparticles, Samiul Hasan

MSU Graduate Theses

The synthesis along with the structural and magnetic properties of manganese (Mn) and cobalt (Co) -incorporated nickel oxide (NiO) inverted core-shell nanoparticles (CSNs) were investigated. The primary objective of this study was to determine the effect of substitution of nickel (Ni) by transition metal ions (Mn²⁺/Co²⁺) in affecting the magnetic properties of the resultant CSNs. The core of the CSNs is comprised of NiO and the shell constitutes a Ni_x(Mn/Co)_1-xO phase. The synthesis of the CSNs was accomplished in two steps: first, NiO nanoparticles were synthesized using a thermal decomposition method. In …

Block Copolymer Nanostructures For Inorganic Oxide Nanopatterning, Krishna Pandey

MSU Graduate Theses

Self-assembled nature of block copolymer (BCP) makes them ideal for emerging technologies in nanometer scale. The micro phase separation between two or more dissimilar polymer blocks of BCP leads to uniform periodic nanostructures of different domains of dimension in the range of 5-100 nm, good for the development of emerging microelectronic and optoelectronics devices. Molecular weight and chain architecture of each blocks govern the morphology evolution; gives different structure like spherical, micelles, lamellae, cylindrical, gyroid etc. The morphology evolution of BCP nanostructure also depends on different external factors as well. In the first work of this thesis, three external factors …

A Comparison Study Of Composite Laminated Plates With Holes Under Tension, Joun S. Kim

Master's Theses

A Comparison Study of Composite Laminated Plates with Holes under Tension

A study was conducted to quantify the accuracy of numerical approximations to deem sufficiency in validating structural composite design, thus minimizing, or even eliminating the need for experimental test. Error values for stress and strain were compared between Finite Element Analysis (FEA) and analytical (Classical Laminated Plate Theory), and FEA and experimental tensile test for two composite plate designs under tension: a cross-ply composite plate design of [(0/90)4]s, and a quasi-isotropic layup design of [02/+45/-45/902]s, each with a single, centered hole of 1/8” diameter, and 1/4" diameter (four sets …