Materials Science and Engineering Commons^™

Shape Memory Alloy Capsule Micropump For Drug Delivery Applications, Youssef Mohamed Kotb

Theses and Dissertations

Implantable drug delivery devices have many benefits over traditional drug administration techniques and have attracted a lot of attention in recent years. By delivering the medication directly to the tissue, they enable the use of larger localized concentrations, enhancing the efficacy of the treatment. Passive-release drug delivery systems, one of the various ways to provide medication, are great inventions. However, they cannot dispense the medication on demand since they are nonprogrammable. Therefore, active actuators are more advantageous in delivery applications. Smart material actuators, however, have greatly increased in popularity for manufacturing wearable and implantable micropumps due to their high energy …

The Effect Of Extended Saltwater Absorption And Uv Cure On The Compressive Properties Of Msla 3d-Printed Photopolymer Resin Samples With Printing Variations, Suzanne Dixon

Theses and Dissertations

Liquid Crystal Display (LCD) 3D printers, also known as Masked Stereolithography Apparatus (MSLA), is a type of vat polymerization printing technique that cures liquid resin into a solid object. This technique is relatively new. Consequently, there is a shortage of detailed research on the impact of long-term environmental exposure on the MSLA-printed materials. The research within this document informs engineers and scientists of resin compressive properties after extended exposure to saltwater and ultraviolet (UV) light. Saltwater absorption of the material was analyzed at atmospheric pressure, 30-psi, 60-psi, and 90-psi; the samples reached saturation in saltwater after 56 days. The variation …

Towards A Practical Method For Monitoring Kinetic Processes In Polymers With Low-Frequency Raman Spectroscopy, Robert Vito Chimenti

Theses and Dissertations

Unlike liquids and crystalline solids, glassy materials exist in a constant state of structural nonequilibrium. Therefore, a comprehensive understanding of material kinetics is critical for understanding the structure-property-processing relationships of polymeric materials. Amorphous materials universally display low-frequency Raman features related to the phonon density of states resulting in a broad disorder band for Raman shifts below 100 cm-1, which is related to the conformational entropy and the modulus. This disorder band is dominated by the Boson peak, a feature due to phonon scattering because of disorder and can be related to the transverse sound velocity of the material, and a …

Applicability Of Using Bio-Receptive Concrete For Building Facades In Egypt, Gina Roupheil

Theses and Dissertations

The significant increase in carbon dioxide emissions caused by the construction industry is detrimental to our planet. This is rapidly increasing with the urbanization of cities that is gradually taking its toll on the available green spaces, which help in balancing such emissions. Recently, researchers have been trying to make use of bio-receptivity to create biomaterial systems that could be spread on building envelopes and support the growth of small plant species and microorganisms to establish on. Out of those materials, comes the concrete as a promising material for bio-colonization.

Within this context, this study aims at investigating the applicability …

Assessing Adoption Barriers Of Sustainable Packaging In Egypt, Carol Ramses Morgan

Theses and Dissertations

Sustainable packaging has become an essential part of business decisions and corporate directions. With the rise of environmental damages due to improper waste management and unsustainable practices, businesses have a major responsibility to analyze their products’ life cycles and redesign them with sustainability in mind. Applying sustainable packaging could save companies large amounts of resources, therefore cutting costs, while also achieving the legal and social duty as a corporation towards society and the environment. Many developing countries, with specific focus on Egypt, have recently focused on legislative and corporate decisions in order to encourage more sustainable practices. Egypt’s new Waste …

A 3d Imaging-Based Critique Of Wire Arc Additive Manufacturing (Waam) Simulations, Omar Oraby

Theses and Dissertations

Residual stresses play a critical role in the mechanical behavior and structural integrity of engineered components. Understanding and quantifying these stresses are essential for ensuring the reliable performance and durability of materials and structures. Traditionally destructive methods are used that involve sample sectioning and material removal. However, non-destructive methods have gained popularity due to their advantages in preserving the specimen's integrity for further testing and material waste reduction. Among these techniques, Digital Image Correlation (DIC) stands out as a powerful non-contact and full-field measurement approach. DIC captures displacements and strain distributions by analyzing the deformation of speckle patterns on the …

Photoluminescence Of Beryllium-Related Defects In Gallium Nitride, Mykhailo Vorobiov, Mykhailo Vorobiov

Theses and Dissertations

This study explores the potential of beryllium (Be) as an alternative dopant to magnesium (Mg) for achieving higher hole concentrations in gallium nitride (GaN). Despite Mg prominence as an acceptor in optoelectronic and high-power devices, its deep acceptor level at 0.22 eV above the valence band limits its effectiveness. By examining Be, this research aims to pave the way to overcoming these limitations and extend the findings to aluminum nitride and aluminum gallium nitride (AlGaN) alloy. Key contributions of this work include. i)Identification of three Be-related luminescence bands in GaN through photoluminescence spectroscopy, improving the understanding needed for further material …

A Precision-Controlled Investigation Into The Fundamentals Which Drive The Incredible Superhydrophobic Properties Of Soot, Ashton Bressler

Theses and Dissertations

A PRECISION-CONTROLLED INVESTIGATION INTO THE FUNDAMENTALS WHICH DRIVE THE INCREDIBLE SUPERHYDROPHOBIC PROPERTIES OF SOOT

By Ashton Bressler

A thesis submitted as a partial fulfilment of the Virginia Commonwealth University requirements for a Masters of Science at Virginia Commonwealth University.

Virginia Commonwealth University, 2024.

This thesis investigates a precision controlled superhydrophobic soot surface, composed of semi-rigid linked chains of spheres, with a radii of roughly 14um. These spheres have exceptionally useful hydrophobic properties due to; their large surface area, their large triple phase line length, their low area fraction of solid-liquid interface, their ability to deform, and their strength from both …

Nano-Patterned Si Structures For Optical Filters And Electro-Mechanical Relays: Fabrication, Characterization, Prospects, And Limitations, Md Ataul Mamun

Theses and Dissertations

Nanofabrication technology, especially nanopatterning, is a rapidly advancing field that has already resulted in creating novel devices and holds promise for producing even more with unmatched performance. These techniques also allow us to gain insight into physical phenomena at the micro- and nanoscale. The ultimate performance of nanofabricated devices and their compatibility with existing Si-based CMOS technology hinge upon the careful selection of materials and precise design, coordinated with meticulous pattern transfer. In this work, we applied nanopatterning techniques on silicon to create optical filters for the shortwave infrared (SWIR) region and nanoelectromechanical system (NEMS) relay-based logic gates. Additionally, these …

Extrusion-Based Additive Manufacturing Of Magnetic Heat Exchange Structures For Caloric Applications, Vaibhav Sharma

Theses and Dissertations

Currently, the commercial building sector accounts for 18% of total U.S. end-use energy consumption, of which almost a third was from on-site combustion of fossil fuels for space and water heating. Magnetic heat pumping (MHP) technology is an energy-efficient, sustainable, environmentally-friendly alternative to conventional vapor-compression cooling technology. Several MHP designs today are predicted to be highly energy efficient, on condition that suitable working materials can be developed. This materials challenge has proven to be daunting due to issues associated with intricate synthesis/post-processing protocols and complications related to shaping the mostly brittle magnetocaloric alloys into thin-walled channeled regenerator structures to facilitate …

Optimizing The Synthesis Process For Lithium-Ion Sieve Adsorbents: Effect Of Calcination Temperature And Heating Rate On Reaction Efficiency And Performance, Calvin Nyambane Nyarangi

Theses and Dissertations

Processing-structure-property relationships play a crucial role in tuning the performance of materials for a given application in order to attain a suitable set of optimal conditions, therefore, it is imperative to evaluate the parameters of either the synthesis, delithiation, adsorption, and desorption process. Through an orthogonal test design of the solid-state synthesis process, it was determined that a heating rate of 1 ℃/min had consistently higher reaction efficiencies of 68.1 %, 68.6 %, and 72.3 % at the calcination temperatures of 650 ℃, 700 ℃, and 750 ℃ respectively compared to heating rates of 4 ℃/min and 7 ℃/min. Moreover, …

High Temperature Oxidation Kinetics Of Alumina Forming Steels For Petrochemical Processes, Kao Zoua Yang

Theses and Dissertations

Petrochemical industries produce 14.33 million barrels of petroleum products a day and by 2023, are expected to produce over a trillion dollars in sales annually. Petroleum is the number one used fuel source and is the raw material used to produce a wide range of petrochemical products including ethylene which is the raw chemical precursors that is crucial to the polymer market. Ethylene is created by the process of cracking ethane and other hydrocarbons in steel reactors at high temperature and potentially oxidizing conditions. The cracking process produces a range of byproducts including a detrimental solid carbon, called coke, which …

Enhanced Biofouling Properties Of Polyethersulfone Membranes Using Multi-Functional Thermo-Responsive Polymers For Ultra-Filtration Applications, Homa Ghasemi

Theses and Dissertations

The accumulation and growth of microorganisms on a membrane surface, known as membrane biofouling, has been a significant issue in the effective use of membrane technology for water and wastewater treatment. To overcome these challenges, this study aimed to modify the surface of a polyethersulfone (PES) membrane through the use of a multi-functionalized thermo-responsive polymer. The primary objectives of chemical treatment on membrane surfaces are to enhance surface hydrophilicity and provide anti-bacterial/biocidal properties.To evaluate the effectiveness of these modifications, the performance of the modified membranes was tested for their ability to resist biofouling through filtration of bovine serum albumin (BSA), …

Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav

Theses and Dissertations

Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …

Elucidating Self-Assembly Of Semiconducting Polymers In The Presence Of A Low Molecular Weight Gelator, Madhubhashini Lakdusinghe

Theses and Dissertations

Semiconducting polymers with a conjugated backbone are important for energy storage, conversion, and biomedical field applications. The self-assembly process of these polymers in solutions depends on the polymer concentration and quality of the solvent. The electrical properties of thin films obtained from the solution phase depend on the self-assembled process. Thin films of conjugated polymer gels with percolating networks of self-assembled structures display improved electrical conductivities. In this dissertation, we studied the impact of the secondary gel matrix formed by a low molecular weight gelator, on the self-assembly of conjugated polymers, the preservation of assembled structures in dried gel films …

Development Of Preservative-Treated Cross-Laminated Timber And Lignin-Reinforced Polyurethane-Adhesive For Glued Laminated Timber, Samuel Oluwafemi Ayanleye

Theses and Dissertations

Interest in the use of mass timber in building and construction is growing worldwide, this is due to the structural integrity and reduced environmental footprint of timber-based structures. Concerns associated with the biological and environmental degradation of mass timber necessitate the development of adequate protection strategies to ensure the durability of these products. Preservative treatment is a proven technique that increases the durability and performance of wood in-service and can also be applied to large-sized timber panels such as cross-laminated timber (CLT). Therefore, this study focused on investigating the feasibility of treating prefabricated 3- and 5-layer CLT panels with Copper-azole …

Mechanical And Microstructural Properties Of 625 Chromia Forming Alloys In Different Temperatures And Atmospheres, Davan Jordan Siegfried

Theses and Dissertations

ABSTRACTMECHANICAL AND MICROSTRUCTURAL PROPERTIES OF 625 CHROMIA FORMING ALLOYS IN DIFFERENT TEMPERATURES AND ATMOSPHERES by Davan Jordan Siegfried The University of Wisconsin-Milwaukee, 2023 Under the Supervision of Dr. Benjamin C. Church Inconel alloys have historically been used in high temperature applications because of two significant reasons: high strength at elevated temperatures and excellent corrosion resistance especially in high temperature applications. The resistivity to chemical attack comes from presence of chromium and molybdenum in the alloy (22 and 9 wt%, respectively) and the formation of chromia on the surface when exposed to oxidizing environments. The formation of chromia on the surface …

Additive Manufacturing Of Stretchable Strain Sensors: Fabrication, Optimization And Application, John Nady Shihat Bastawrous

Theses and Dissertations

In this project, a novel strain sensor design is fabricated employing different additive manufacturing techniques. The spring sensor's primary material is PLA-Like resin with a nanocomposite encapsulation layer as the functional material. The main principle of Straining the sensors results in a change in resistivity as the distances among the conductive carbon particles change according to the strain applied.

Sensor fabrication consists of two parts: spring manufacturing and development of nanocomposite encapsulation The nanocomposite matrix is developed through the dispersion of Graphene and Carbon nanotubes in Thermoplastic Polyurethane through sonication and magnetic hotplate stirring. While the spring itself is manufactured …

Flexural Wave Manipulation By Non-Hermitian Planar Elastic Metasurface, Katerina Stojanoska

Theses and Dissertations

It has been demonstrated that metasurfaces with spatially asymmetric inner geometry exhibit unidirectional scattering effects, which can be used to control waves in a directional fashion. In this thesis, a planar Non-Hermitian elastic metasurface exhibiting unidirectional focusing of flexural waves is proposed. Asymmetrically loaded piezoelectric disks and metallic blocks comprise the unit cells. By using a negative capacitance shunting, a tunable material loss is embedded into the system. With suitable engineering of the induced loss profile, resonating building blocks are designed, which are capable of independently accessing unidirectional zero reflection. A planar metasurface is then created so that constructive interference …

Integrating Steel Slag Aggregates Into Asphalt Paving By Harmonizing Availability, Quality, Economics, And The Environment, Timothy R. Murphy

Theses and Dissertations

This thesis provides guidance on how to balance matters related to the environmental stewardship, market sources, origin and uses, material properties, performance, and economic impact of using slag materials in pavements. The literature on this topic provides numerous references on the use of slag materials for specific applications, and this thesis aims to make use of those references along with other data from the author to describe slag materials from a holistic perspective and provide some suggestions for balancing several factors that impact optimal use of this resource within pavement structures. Discussion is given to the increased importance of recycling …

Materials And Methods For Digital Construction, Milad Hajipour Manjili

Theses and Dissertations

The benefits of digital manufacturing and 3D printing technology when applied in the construction industry have proven to demonstrate considerable advantages over conventional production methods including increase in efficiency, reduced labor, ability to realize complex architecture and design optimization to effectively utilize materials characteristics and decrease production waste. For industry today, the 3D printing has emerged to address many of the needs to improve the material performance, enhance properties, and deliver complex structures with efficiency. In the case of concrete, the extension of the extrusion method to 3D (and even 4D) printings is the technological challenge that requires the modification …

Rapid Synthesis Of Dual-Layered Covalent Organic Framework Membranes Via Interfacial Polymerization With Enhanced Desalination Performance, Miguel Angel Jaimes

Theses and Dissertations

As a consequence of disrupting the water cycle via human interventions, such as climate change, humanity is facing global water crises. The water crises are wide ranging, but often associated with the deterioration of a local water cycle’s capacity to support a population. This capacity is reduced on a global scale through the atmosphere via climate change, but on a local scale, it can be reduced because of an over extraction of resources, alteration of ecosystems, and water pollution. The deployment of desalination plants is growing around the world. Reverse osmosis (RO) desalination is much more efficient than the thermal …

Experimental And Computational Bearing Strength Of Fiber Metal Laminate With And Without Film Adhesive, Christopher L. Bellanova Jr.

Theses and Dissertations

This research characterized the performance of a fiber metal laminate composed of carbon fiber and stainless steel without film adhesive and compared it to a similar, previously tested, fiber metal laminate including film adhesive. Removal of the adhesive layers reduced the localized thickness, simplified manufacturing, and allowed for a 20% increase in foil thickness. Quasi-static testing was conducted in double shear, single shear protruding, and single shear countersunk configurations. The results were compared to adhesive hybrid and control samples. To study the affects of bolt tension, samples at low torque in double shear were also tested. Progressive failure samples revealed …

Anisotropic Characterization Of Additively Manufactured Ti 6-4 Via Tension, Compression, And Three Point Bend Experimentation, James M. Gunderson

Theses and Dissertations

Titanium's ability to fill existing material gaps because of its higher strength and higher melting temperature compared to other common materials used in aircraft structures requires a need to understand the behavior of the material. Titanium's properties and the development of additive manufacturing also open an opportunity for it to be used in aerospace systems of the future in applications where traditionally manufactured titanium cannot meet the desired system requirements. Compressive, tensile, and three point bend experimental data collected from this research under varying temperatures, print orientations, print layer build heights, and surface finishes were analyzed to determine favorable material …

Development Of Novel Turbomachinery Manufacturing Methods, Timothy P. Winkler

Theses and Dissertations

Compact turbine engines are of increasing interest as a means of propulsion for small, lightweight, low cost, unmanned aerial systems. This study looks to leverage advancements in novel manufacturing technology to produce turbomachinery components while simultaneously reducing costs and manufacturing time. To determine the feasibility of drop-in replacements for stock components this study focused on several research areas. This included materials research on both polymer-reinforced and ceramic materials, specimen tensile testing to determine temperature-dependent material properties, finite element analysis of multiple candidate materials, design and fabrication of a spin test rig, and physical spin testing of manufactured components to predict …

Accurate Evaluation Of The Direction-Dependent Mechanical Properties Of Ideal Single Crystals: A Comparative Ab Initio Study, Jaylan Ali Elhalawani

Theses and Dissertations

The mechanical properties of a single crystal or a grain in a polycrystalline material are highly dependent on the direction of the applied load. Key properties of interest are the Young’s modulus and the Poisson ratio in the small strain limit, and the ideal tensile strength in the large strain regime. Prior atomistic computations of these properties interchangeably used two approaches. In one approach the stress-strain response is explicitly calculated via a numerical tensile test experiment. In the second approach the second order single crystal elastic constants are computed via small deformations and then used in analytical equations to derive …

Polyethersulfone Thin-Film Nanocomposite Membrane Embedded With Amine-Functionalized Graphene Oxide For Desalination Applications, Ahmed Bahaeldin

Theses and Dissertations

Thin-film nanocomposite (TFN) desalination membranes were prepared based on a polyethersulfone (PES) support, where the polyamide (PA) layer was embedded with amine-functionalized graphene oxide (GO). The effect of adding various concentrations of functionalized and un-functionalized GO on the desalination performance, hydrophilicity, and morphology of the membranes was additionally assessed throughout this work. Scanning electron microscopy (SEM) measurements were used to assess the morphology of the membranes in combination with Brunauer-Emmett-Teller (BET) analysis. Contact angle measurements were used to gauge the hydrophilicity of the synthesized membranes. The membrane with the best desalination performance contained 1x10^-3 wt/vol% of functionalized GO in …

Aerosol Synthesis Of Tungsten Bronze Particles For Nir Shielding, Hao Tu

Theses and Dissertations

This dissertation emphasizes the need for efficient energy use in buildings and transportation due to global warming and the energy crisis. It suggests that improving energy efficiency can help reduce energy consumption and emissions and support sustainability. The dissertation introduces various transparent materials that can block near-infrared (NIR) radiation from solar radiation to save energy and money, and it highlights the growing market value of such products. The dissertation compares tungsten bronze with other NIR shielding materials and shows its advantages. The dissertation introduces a cheap and environmentally friendly method for continuously producing tungsten bronze particles via aerosol synthesis. Particle …

Radiation Shielding Effectiveness Of Hafnium Diboride (Hfb2) Reinforced Epoxy Composites For Enhanced Radiation Protection And Safety, Furkan Erdogan

Theses and Dissertations

This thesis investigates the radiation shielding effectiveness of hafnium diboride (HfB2) reinforced epoxy composites, with the aim of enhancing radiation protection and safety in various applications. The study focuses on the development and characterization of HfB2-epoxy composites with varying weight percentages of HfB2 nanoparticles, as well as on the evaluation of their shielding effectiveness against gamma rays and thermal neutrons. The radiation shielding performance of the composites is assessed using gamma-ray spectroscopy and neutron counting, and the neutron attenuation efficacy is compared with that of 5% borated high-dense polyethylene. The results indicate that the HfB2-epoxy composites exhibit promising radiation shielding …

A Constitutive Material Model For Simulating Texture Evolution And Anisotropy Effects In Cold Spray., Creston Michael Giles

Theses and Dissertations

Cold spray has seen rapid advancement since its inception and has shown significant potential as a method of additive manufacturing. However, the large plastic deformation and repeated heating/cooling cycles that the material undergoes during the cold spray process can result in gradients in material structure and large residual stresses. The purpose of this study is to extend the existing EMMI material model to include anisotropic material response through the use of orientation distribution functions to predict residual stresses and anisotropy resulting from cold spray and similar additive manufacturing processes. Through the use of a finite element simulation, yield surfaces for …