Materials Science and Engineering Commons^™

Effects Of Surface-Directed Spinodal Decomposition On Binary Thin-Film Morphology, Michael Brian Wise

Graduate Theses and Dissertations

Preferential wetting can have a significant impact on the kinetics of phase separation in certain systems. The depletion of the wetting component can simply alter domain growth rates or change the structure entirely. In this thesis, we employ a Cahn-Hilliard model to study the evolution of binary thin-films with symmetric surface wetting. Three possible morphologies were identified: discrete, bicontinuous, and a novel quasi-2D bicontinuous structure in which both phases retain continuity throughout the volume as well as on the center xy plane. Using a continuity factor, regions of film thickness versus blend composition were classified as producing a certain morphology. …

Thermoelectrics And Thermoelectric Devices, Benjamin T. Erck

Senior Theses

The field of thermoelectrics has many applications, and more are found in everyday systems. From its current studies, it is apparent that improving the figure of merit zT (which defines a good thermoelectric material) is important in the effectiveness of power generation. Another important part of thermoelectrics is the duality of these devices. They can both move heat and generate power, depending on their role in the system. In this thesis research, a process was made to test these thermoelectric relationships for a few Peltier devices in order to understand their efficiencies and what systems they can be applied to.

Fabrication Of Solid Polymeric 3d Shapes From Programmable Flat Hydrogel Sheets, Ninad Vilas Khadse

Material Science and Engineering Theses - Archive

Modern methods of fabricating three-dimensional (3D) objects include sheet metal forming, thermoforming, and additive manufacturing among others. These methods have their own advantages and disadvantages regarding scalability, customizability, and time efficiency. A promising approach is to program the growth (expansion and contraction) of hydrogel sheets to form 3D structures. The differential growth-induced 3D shaping approach has the advantages of traditional manufacturing (scalability) and additive manufacturing (customizability). The objective of this study is to create nanocomposite 3D structures that are stable in ambient environment using the growth-induced 3D shaping approach. This study determines the effect of silica nanoparticles in hydrogels on …

Characterization Of Normal And Abnormal Bones By Raman Spectroscopy : Analysis Of Mineral To Matrix Ratio Of Bone Using Advanced Materials Characterization Techniques, Meet Yagnesh Shah

Material Science and Engineering Theses - Archive

Bone disorders and disease are associated with multiple factors. Some of the disorders and diseases are difficult to understand because of their unknown root causes. Our goal was to differentiate between normal and genetically modified rat bone groups by finding the difference in mineral to matrix (Mn/Mx) content using Raman spectroscopy. Raman spectroscopy gives the chemical composition based on the vibration modes of the molecules. Quantitative analysis of Mn/Mx content calculated from Raman spectra allowed us to distinguish between healthy and genetically modified rat bone groups. We have presented the results by averaging the Mn/Mx ratios. Thus, the most significant …

Quantitative Analysis Of Mineral/Matrix To Evaluate Genetically Altered Bone With Infrared Spectroscopy And X-Ray Spectral Imaging, Sunil Balasaheb Yadav

Material Science and Engineering Theses - Archive

This thesis focuses on the characterization of bone with the help of Fourier Transform Infrared Spectroscopy and Energy Dispersive Spectroscopy. Such analysis of the physics and chemistry of biomaterials is vital to resolve problems in life science of bone-related diseases and disorders. Material characterization can help in the understanding of disease mechanisms and lead to useful drugs and other treatments. In this thesis, I have used bone materials produced by groundbreaking research at UT Southwestern Research Center and Texas Scottish Rite Children's Hospital to establish that idiopathic clubfoot (Talipes equinovarus) is associated with the Follistatin 5 gene. We studied healthy …

Study Of Copper-Rich Intermetallic Phase Formation In Copper-Aluminum Binary System, Valery Georges Ouvarov-Bancalero

Material Science and Engineering Dissertations - Archive

This work aims to study the initial formation and subsequent growth of intermetallic compounds (IMC) in the binary Al-Cu system. Al-Cu pair configurations have been successfully used for several decades as structural components, and extensive research on their mechanical and metallurgical properties is available. More recently, the microelectronics industry started implementing the Cu wire-bond technology, which renewed the interest of the scientific community. As with every technological evolution, initial quality and reliability issues arose. Copper (Cu) wire to aluminum (Al) bond-pad is prone to crack nucleation leading to failure at the interface between Cu and Cu-rich IMCs. Even though numerous …

Accelerated Creative Problem Solving And Product Improvement Applied To Experimental Devices In A Bloodstain Pattern Interpretation Class--Improving The Role Of Insight Development Tools As A Generator Of New Ideas In Novel Situations, Douglas Ridolfi

Creativity and Change Leadership Graduate Student Master's Projects

This project uses an action research centered study protocol to examine the effects of a problem-based learning exercise related to bloodstain pattern interpretation in a crime scene processing and general criminalistics class taught as part of an upper division forensic chemistry major in a four year college. The goal is to apply design principles and creative problem solving methods directly adapted to a project involving interpreting a set of crime scene photographs depicting blood spatter and with the aid of guided exercises in ideation and design, lead students into the development of alternate theories of how the bloodstains were created …

Phase Field Model Of Thermally Induced Phase Separation (Tips) For The Formation Of Porous Polymer Membranes, Ashley Green, Aria Green

Mechanical Engineering Undergraduate Honors Theses

Most membrane research and development has been done through experimental work, which can be costly and time consuming. An accurate computational model would greatly reduce the need for these experiments. The focus of the research presented in this paper is to create an accurate computational model for membrane formation using thermally induced phase separation (TIPS). A phase field model is employed to create this model including the Cahn Hilliard Equation and Flory Huggins Theory. This model produced computational results that correspond well with theoretical and experimental results. The model was then adapted to correspond to the PVDF/DPC polymer-solvent system by …

Influence Of Impact Conditions On Feedstock Deposition Behavior Of Cold-Sprayed Fe-Based Metallic Glass, Constance Ziemian, Wendelin Wright, David E. Cipoletti

Faculty Journal Articles

Cold spray is a promising method by which to deposit dense Fe-based metallic glass coatings on conventional metal substrates. Relatively low process temperatures offer the potential to prevent the crystallization of amorphous feedstock powders while still providing adequate particle softening for bonding and coating formation. In this study, Fe48 Mo14 Cr15 Y2 C15 B6 powder was sprayed onto a mild steel substrate, using a variety of process conditions, to investigate the feasibility of forming well-bonded amorphous Fe-based coatings. Particle splat adhesion was examined relative to impact conditions, and the limiting values of temperature and velocity associated with successful softening and …

Aerospace Mission Outcome: Predictive Modeling, Ephraim Suhir

Mechanical and Materials Engineering Faculty Publications and Presentations

Human-in-the-Loop (HITL)-related models can be applied in various aerospace vehicular problems, when human qualifications and performance are crucial and the ability to quantify them is therefore imperative; since nobody is perfect, these evaluations should preferably be done on a probabilistic basis. The suggested models can also be used in many other areas of applied science and engineering, not even necessarily vehicular engineering, when a human encounters an extraordinary situation and should possess a sufficiently high human capacity factor (HCF) to successfully cope with an elevated mental workload (MWL). The incentive for probabilistic predictive modeling and the rationale for such modeling …

Detection And Prediction Of Defects In Composite Materials Using Di-Electric Characterization And Neural Networks, Muthu Ram Prabhu Elenchezhian, Aishwarya Nandini, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

The state of art non-destructive inspection techniques for composite materials detect the presence of defects in the composite material, but they do not identify what type of defect it is, and hence, further visual inspection of the details are needed. This visual classification is a costly and time-consuming process, and it’s difficult to distinguish all of the defects effectively. Broadband Dielectric Spectroscopy (BbDS), has been an established tool for dielectric material characterization in polymer industries for a long time. Dielectric spectra of heterogeneous materials are altered by constituent interfaces, with changes in morphological heterogeneity, electrical and structural interactions between particles, …

Thiol–Ene Photopolymerization: A Simple Route To Pro-Antimicrobial Networks Via Degradable Acetals (Pandas), William Martin

Honors Theses

The World Health Organization (WHO) has brought the growing epidemic of antibiotic resistance bacteria to the attention of the public and has expressed the need for the development of new methods of defense. In this direction, bioactive aldehyde essential oils have been shown to effectively act as antibiotic and antifungal agents. These bioactive compounds, when used in their pure form, are volatile and lack environmental stability. In this thesis, we describe the synthesis of pro-antimicrobial networks via degradable acetals (PANDAs) using thiol-ene photopolymerization. PANDAs were used as a new model for the high loading and release of bioactive aldehyde-containing compounds …

Corner Sealants For Tactical Shelters, Janine Carlita Nowak

Honors Theses

The demand for a lightweight, easy-assembly tactical shelter is high for those faced with unexpected disasters and global conflicts. This project focuses on designing and prototyping the corner sealant for such a shelter. Two materials were chosen and tested: an in-house thermoplastic polyurethane (TPU) and Texin 950. Thermogravimetric Analysis (TGA) was performed on both of these materials. The in-house TPU showed initial degradation at 282.50 °C and sample degradation at 457.45 °C. Similarly, Texin 950 showed initial degradation at 293.68 °C and sample degradation at 453.26 °C. Differential Scanning Calorimetry (DSC) was then run. The crystallization temperature (Tc) was observed …

The Natural Aging Effect On Hardenability In Al-Mg-Si: A Complex Interaction Between Composition And Heat Treatment Parameters, Alex Poznak, Violet Thole, Paul G. Sanders

Michigan Tech Publications, Part 1

The technological relevance of Al-Mg-Si alloys has been rapidly growing over the last decade. Of particular interest to current and future applications is the problematic negative effect of prior natural aging on subsequent artificial age hardening. The influence of natural aging is dependent on both processing and compositional variables and has origins that are far from well-understood. This work examines the hardenability of 6000 series alloys under a wide range of conditions, paying particular attention to the natural aging effect. Experimental variables include alloy composition (Mg + Si, Mg/Si), cooling rate after solutionization, and duration of prior natural aging. Hardenability …

Peridynamic Modeling Of Dynamic Fracture In Bio-Inspired Structures For High Velocity Impacts, Sneha Akula

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

Bio-inspired damage resistant models have distinct patterns like brick-mortar, Voronoi, helicoidal etc., which show exceptional damage mitigation against high-velocity impacts. These unique patterns increase damage resistance (in some cases up to 3000 times more than the constituent materials) by effectively dispersing the stress waves produced by the impact. Ability to mimic these structures on a larger scale can be ground-breaking and could be used in numerous applications. Advancements in 3D printing have now made possible fabrication of these patterns with ease and at a low cost. Research on dynamic fracture in bio-inspired structures is very limited but it is …

Design, Fabrication, And Characterization Of All-Inorganic Quantum Dot Light Emitting Diodes, Ramesh Vasan

Graduate Theses and Dissertations

Quantum dot light emitting diodes are investigated as a replacement to the existing organic light emitting diodes that are commonly used for thin film lighting and display applications. In this, all-inorganic quantum dot light emitting diodes with inorganic quantum dot emissive layer and inorganic charge transport layers are designed, fabricated, and characterized. Inorganic materials are more environmentally stable and can handle higher current densities than organic materials. The device consists of CdSe/ZnS alloyed core/shell quantum dots as the emissive layer and metal oxide charge transport layer. The charge transport in these devices is found to occur through resonant energy transfer …

Glucose Level Estimation Based On Invasive Electrochemical, And Non-Invasive Optical Sensing Methods, Sanghamitra Mandal

Graduate Theses and Dissertations

The purpose of this research is to design and fabricate sensors for glucose detection using inexpensive approaches. My first research approach is the fabrication of an amperometric electrochemical glucose sensor, by exploiting the optical properties of semiconductors and structural properties of nanostructures, to enhance the sensor sensitivity and response time. Enzymatic electrochemical sensors are fabricated using two different mechanisms: (1) the low-temperature hydrothermal synthesis of zinc oxide nanorods, and (2) the rapid metal-assisted chemical etching of silicon (Si) to synthesize Si nanowires. The concept of gold nano-electrode ensembles is then employed to the sensors in order to boost the current …

Fabrication And Characterization Of Graphene Based 2d Materials For Supercapacitors, Anishkumar Manoharan

Graduate Theses and Dissertations

Supercapacitors have attracted a lot attention due to their efficient energy storage. In comparison to batteries, supercapacitors have high capacitance, energy, and power densities per unit mass than conventional capacitors. Carbon based materials are most promising in supercapacitor application due to their outstanding physical and electrochemical behavior. In this work, a facile method to synthesize a nanocomposite electrode consisting of annealed carbon from carbon ink and MoS2 was demonstrated. Effects of various aqueous and solid electrolytes were studied. It was found that the nanocomposite electrode with 10% MoS2 and 1M Na2SO4 as the aqueous electrolyte tested using the three electrode …

Understanding The Evolution Of Surface Texture Under Boundary Lubrication, Salil T. Bapat

Graduate Theses and Dissertations

The objective of this research was to understand the evolution of surface texture under boundary/mixed lubrication (BL). Significant material/energy losses occur during BL because of direct contact between the two surfaces. Traditionally, tribofilms have been studied extensively for BL while textures have been used as a static engineering design parameter to enhance lubricant film properties. However, texture is dynamic at the tribological mating interface, where both physical and chemical interactions are continuously modulated. The evolution and the interplay between the tribofilm and texture is least studied in the literature, which is the focus of this research.

MoS2-based lubricants, known for …

Dielectric Property Investigation Of Degraded Pre-Preg And Performance Prediction Of The Final Composite Part, Aishwarya Nandini, Nina Shute, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

In recent years, fiber-reinforced (i.e., Glass, Carbon, Kevlar) epoxy composites are used widely in structural applications ranging from military and civil aircraft production to recreational consumer products. Most of the industries use pre-impregnated varieties of composite (prepregs) to make high-quality composite parts. Despite their various advantages, prepreg materials are unstable at ambient temperature. A realistic estimation of the shelf life of prepreg is therefore essential for maintaining quality while reducing wastage of resources. Prepregs are temperature and moisture sensitive material systems. To achieve prolonged shelf life, manufacturer and seller of the prepreg must store the materials at zero degrees Celsius …

Design, Fabrication, And Characterization Of Novel Optoelectronic Devices For Near-Infrared Detection, Ahmad Nusir

Graduate Theses and Dissertations

Investigating semiconductor materials and devices at the nanoscale has become crucial in order to maintain the exponential development in today’s technology. There is a critical need for making devices lower in power consumption and smaller in size. Nanoscale semiconductor materials provide a powerful platform for optoelectronic device engineers. They own interesting properties which include enhanced photoconductivity and size-tunable interband transitions.

In this research, different types of nanostructures were investigated for optoelectronic devices: nanocrystals, nanowires, and thin-films. First, lead selenide nanocrystals with narrow bandgap were synthesized, size-tailored, and functionalized with molecular ligands for the application of uncooled near-infrared photodetectors. The devices …

Optically Active Dye-Based Systems Templated By Dna Exhibiting Excitonic Delocalization, Brittany Lynn Cannon

Boise State University Theses and Dissertations

The concept of quantum computing was first developed in the early 1980’s. The attraction of quantum computers is their potential capacity to solve extremely complex problems, such as factorization, on a timescale far faster than that of classical computers. However, realization of quantum computation is currently in its infancy, and recent implementations possess serious drawbacks that reduce their appeal. Some challenges of current designs include the necessity to cool the systems using liquid helium to near absolute zero temperatures (15 mK) in order to maintain sufficiently long-lifetimes of the Qbits (i.e., unit of quantum information), difficulty with scaling up the …

Osteoprogenitor Cell Adhesion And Growth On The Bioactive Silicon Nitride Surface For Craniofacial Implants Applications, Kamal Awad

Material Science and Engineering Theses - Archive

As a novel biomaterial, silicon nitride (Si3N4) has been used for orthopedic and spinal fusion applications. Its ability to promote continuity for structural support of missing bone, by in/on bone growth, gives it advantageous properties and potential for mandibular and craniofacial reconstruction applications. Yet, the surface properties of this material and its effect on the osteogenic properties have not been fully realized. Thus, the aim of this study was to evidently investigate the surface properties of the bioactive Si3N4 that enhance the calvarial osteoblasts cell adhesion, growth, and differentiation when compared to conventional implant materials such as titanium (Ti) and …

Nature Inspired Technology: A New Process For Silicification Based On Marine Sponges, Ami Atul Shah

Material Science and Engineering Dissertations - Archive

Silica is used in various industries, ranging from automobile industry for tires to semiconductor industry, paints and coatings, biomedical devices & applications to food & drug industry. The current processing techniques for precipitated silica involve harsh conditions like high temperature and extreme pH conditions. Nature already has highly evolved production techniques for silica. They run at physiological conditions and exhibit intricate control over the synthesis, leading to very pure and ornate siliceous structures. These structures exhibit organized architecture at scales as small as nano-dimensions. The proposed research work is a step, towards development of new techniques that bio-mimic the silica …

Investigation Of The Processing-Structure-Property Relationship In Ta-Si-N Nanocomposite Coatings, Anna Zaman

Material Science and Engineering Dissertations - Archive

The present-day industry demands development of coatings for harsh environmental applications which can resist impact and oxidation at high temperatures. It is vitally important to develop new hard (>30 GPa) protective coatings which will be thermally stable at temperatures, T > 800 °C and simultaneously will ensure a good protection of the substrate against oxidation from an external atmosphere. The limitations of conventional coatings due to inferior hardness or poor oxidation stability can be overcome by nanocomposite coatings as they exhibit enhanced and completely new properties. To address this requirement of new enhanced protective systems, there is a need to …

Polymer Nanocomposites Containing High Aspect Ratio Particulates: Innovation In Co-Extruded Multilayer Barrier Films, Kevin Meyers

Dissertations

Delaminated montmorillonite (MMT) clay/ maleic anhydride grafted LLDPE nanocomposite multilayer films with alternating layers of LDPE were produced through multilayer co-extrusion. The MMT concentration within the nanocomposite layers was increased through annealing the films in the melt due to a mismatch in interdiffusion rates of the polymer layers. Analysis of the nanocomposite layers upon annealing revealed that the platelets impinged upon one another resulting in significant improvement in oxygen barrier in the multilayer system, exceeding the results of bulk nanocomposites.

Model analysis demonstrated that increasing the nanoplatelet aspect ratio or initial concentration in the filled layers would lead to even …

Antimicrobial Materials Via Thiol-Ene Chemistry, Dahlia Amato

Dissertations

With the increasing prevalence of antimicrobial resistance, the escalation of opportunistic/pathogenic infections is a looming global crisis. To avoid the pitfalls of conventional antibiotics, this dissertation focuses on developing macromolecular solutions to develop novel antimicrobial materials based on essential oils (thymol, carvacrol, and aldehydes). It is well established that essential oil derivatives exhibit high potency towards a wide range of pathogenic microbes. The rapid photopolymerization kinetics, limited by-products, and homogeneous network formation afforded by thiol-ene photopolymerization are utilized to either encapsulate essential oil derivatives or convert them into monomers which can subsequently be incorporated into new antimicrobial materials with new …

Molybdenum Sulfide Prepared By Atomic Layer Deposition: Synthesis And Characterization, Steven Payonk Letourneau

Boise State University Theses and Dissertations

Molybdenum disulfide (MoS₂) is the prototypical two-dimensional (2D) semiconductor. Like graphite, it has a layered structure containing weak van der Waals bonding between layers, while exhibiting strong covalent bonding within layers. The weak secondary bonding allows for isolation of these 2D materials to single layers, like graphene. While bulk MoS₂ is an indirect band gap semiconductor with a band gap of ~1.3 eV, monolayer MoS₂ exhibits a direct band gap of ~1.8 eV, which is an attractive property for many opto-electronic applications. Atomic layer deposition (ALD) has been used to grow amorphous films of MoS_{2 …}

Self-Assembly Of (111)-Oriented Tensile-Strained Quantum Dots By Molecular Beam Epitaxy, Christopher F. Schuck, Robin A. Mccown, Ashlie Hush, Austin Mello, Simon Roy, Joseph W. Spinuzzi, Paul J. Simmonds

Materials Science and Engineering Faculty Publications and Presentations

The authors report on a comprehensive study of the growth of coherently strained GaAs quantum dots (QDs) on (111) surfaces via the Stranski–Krastanov (SK) self-assembly mechanism. Recent reports indicate that the long-standing challenges, whereby the SK growth mechanism could not be used to synthesize QDs on (111) surfaces, or QDs under tensile strain, have been overcome. However, a systematic study of the SK growth of (111)-oriented, tensile-strained QDs (TSQDs) as a function of molecular beam epitaxy growth parameters is still needed. Here, the authors explore the effects of deposition amount, substrate temperature, growth rate, and V/III flux ratio on the …

Routine Million-Particle Simulations Of Epoxy Curing With Dissipative Particle Dynamics, Stephen Thomas, Monet Alberts, Michael M. Henry, Carla E. Estridge, Eric Jankowski

Materials Science and Engineering Faculty Publications and Presentations

Mesoscale simulation techniques have helped to bridge the length scales and time scales needed to predict the microstructures of cured epoxies, but gaps in computational cost and experimental relevance have limited their impact. In this work, we develop an open-source plugin epoxpy for HOOMD-Blue that enables epoxy crosslinking simulations of millions of particles to be routinely performed on a single modern graphics card. We demonstrate the first implementation of custom temperature-time curing profiles with dissipative particle dynamics and show that reaction kinetics depend sensitively on the stochastic bonding rates. We provide guidelines for modeling first-order reaction dynamics in a classic …