Materials Science and Engineering Commons^™

Magnetic Augmented Rotation System (Mars ) - Properties And Performance, Ruolei Liu

Theses

Magnetic Augmented Rotation System (MARS) is proposed as a system for conversion of mechanical energy into electrical energy. It works on the principle of magnetic coupling. Because it is contactless, compared with traditional gears, it increases the transfer efficiency from a driver to a rotor; reduces noise, requires no lubrication and has low maintenance cost. In order to assess the performance of MARS, a charging system based on MARS is implemented. This system includes rechargeable batteries in the range of 6 volts to 12 volts, a load in the form of a light bulb, a voltage transformer, and digital multimeter …

A Computational Model For Transdermal Diffusion Of Lidocaine And Tetracaine Topical Patches, Qian Dong

Theses

In recent years, transdermal drug delivery patches (TDDP) have developed rapidly. This is because the TDD system has more advantages than traditional drug delivery systems such as oral medicine and intravenous injection. In order to reach the circulatory system of the human body, drug molecules have to pass through the epidermis (outer layer) of the skin. The barrier properties of epidermis originate from low permeability of stratum corneum (SC) which is the outermost layer of the human skin. The objective of this thesis is to build a Finite Element (FE) model, utilizing commercial FE software (ANSYS), that can be implemented …

Koh Etching Of Silicon, Ying Wang

Theses

In this research, a series of comparative etching experiments on silicon wafers have been carried out using potassium hydroxide (KOH) for different experimental etching conditions for concentration, temperature and time on (100) orientation p-type silicon wafers. Besides the basic etching conditions, the position of the immersed wafer also has unpredictable effect on the etching process. This may be attributed to the relative contact position between the surface of the immersed wafer and the flow patterns of the stirred etching solution.

The surface morphology analysis indicates that the specific position of the wafer, with respect to the flow of the etchant, …

Infrared Imaging - Case Studies And Applications, Shuang Du

Theses

Recent advancements in the manufacture of solid state detectors have led to significant improvements in the use and applications of infrared (IR) imaging. Compared with traditional imaging in visible light, infrared imaging has abilities to convey significant additional information. Applications in medicine require wavelengths in the range of 0.8 to 25 microns while metrology and astronomy, traditionally, require wavelengths in the range of 25 microns to 1 mm.

In this study, infrared imaging has been used as a tool to characterize a variety of objects and systems. Some of these case studies have been considered under conditions of thermodynamic non-equilibrium. …

Diffusivity Of Drug Actives In Transdermal Drug Delivery (Tdd), Natali R. Gendelberg

Theses

Transdermal Drug Delivery (TDD) through skin patches has many advantages including the following: slow and continuous administration of the therapeutic over long periods of time, timely dosage, accessibility, kinetic maneuverability, elimination of the “First Pass Effect” and negative side effects on the digestive tract. All of the above justify investment into further development of TDD therapies, despite the skin permeability restrictions posed on size and charge by the skin. As skin permeability varies between all individuals based on age, ethnicity and lifestyle, the determination of the proper drug dosages to be contained in the skin patch is highly reliant on …

Design, Testing, Analysis, And Material Properties Of Carbon Fiber Reinforced Polymers, Andrew Miner, Simon Jones

Rose-Hulman Undergraduate Research Publications

Rose-Hulman Institute of Technology excels in many fields, however in the field of Carbon Fiber Reinforced Polymers (CFRPs) there is a significant lack of knowledge. Over the 2015 summer I started accumulating and building a knowledge base for the institute to help future students who have interest in this ever expanding field. This report covers many of the learnings I found in the structures of fiber reinforced polymers, manufacturing processes and controls, testing procedures and standards, important considerations in the design process of CFRPs, and analysis capabilities and methods. This report is organized as a series of short guides to …

Zno Thin Films Generated By Ex-Situ Thermal Oxidation Of Metallic Zn For Photovoltaic Applications, Kovas Zygas

Macalester Journal of Physics and Astronomy

ZnO thin films that function as either transparent conducting oxides in solid-state photovoltaic cells or as nanocrystalline dye-absorbers in dye-sensitized solar cells have the potential to reduce the cost of producing electricity from solar energy. Although there exist many methods to produce ZnO thin films, the most economical and practical method may be oxidation of metallic Zn thin films. This research examined the utility of ex-situ thermal oxidation of DC magnetron sputtered Zn thin films in generating useful ZnO thin films for these photovoltaic applications. We annealed Zn thin films in air at 570° C in order to produce ZnO …

Reflective Efficiencies Of Materials For Applications Of Bifacial Solar Cells, Michael Metter

Senior Theses

The bifacial solar cell is superior to its monofacial predecessor due to its ability to convert both incident light on top and reflected light from below into energy. The scattering of the reflected light is affected by the property of the material on which it is interacting. To date, little work has been contributed to studying the properties of these materials to determine optimal quantities for bifacial solar cells. In the first experiment, reflective efficiencies compared to the angle of reflection were explored for different grit of sandpaper in order to develop an understanding of how surface texture impacts reflectivity. …

Searching To Distinguish Defects And The Presence Of Negative Capacitance, Thaddeus Cox

Senior Theses

In the search for solar cells with lower manufacturing costs, thin film technology was developed. These thin films are only micrometers thick and are grown at relatively low temperatures, resulting in films with imperfections known as defects. Defects can cause thin film solar cells to have lower efficiencies than their single crystalline counterparts. In order to create more efficient thin film solar cells the physical mechanisms behind defects need to be investigated by sensitive techniques. Capacitance measurements of solar cells detect minute changes in charge in the material. For that reason, capacitance is used to electrically characterize the solar cell. …

Theory Of Carrier Transport From First Principles: Applications In Photovoltaic And Thermoelectric Materials, Alireza Faghaninia

McKelvey School of Engineering Graduate Student Theses & Dissertations

New sources of energy that are environmentally friendly, cost-effective, and renewable are essential if we are to combat the effects of global climate change. Two of these sources are solar photovoltaic (PV) cells to convert sunlight into electricity and thermoelectric (TE) devices to convert heat to electricity. To be practical on a large scale, the properties (e.g. electrical conductivity, band gap, Seebeck coefficient, etc) of the the underlying materials must be improved significantly through judicious control of structure and composition. Significant understanding of materials properties is required to design and engineer new high-performing materials. First principles calculations using density functional …

Size Effect On The Magnetic Phase In Sr4Ru3O10, Yan Liu, Jiyong Yang, Weike Wang, Haifeng Du, Wei Ning, Langsheng Ling, Wei Tong, Zhe Qu, Zhaorong Yang, Minling Tian, Gang Cao, Yuheng Zhang

Center for Advanced Materials Faculty Publications

High quality Sr₄Ru₃O₁₀ nanoflakes are obtained by the scotch tape-based micro-mechanical exfoliation method. The metamagnetic transition temperature T_m^flake is found to decrease in line with the decrease of thickness, while the ferromagnetic (FM) phase, the ordinary, and anomalous Hall effects (OHE and AHE) are independent on the thickness of the flake. Analysis of the data demonstrates that the AHE reflects the FM nature of Sr₄Ru₃O₁₀, and the decrease of thickness favors the Ru moments aligned in the ab-plane, which induces a decrease of the metamagnetic transition …

Effect Of The Inherent Eccentricity In Single-Lap Direct-Shear Tests Of Pbo Frcm-Concrete Joints, Tommaso D'Antino, Lesley Sneed, Christian Carloni, Carlo Pellegrino

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Investigation of the bond between fiber reinforced composites and the substrates onto which they are applied is of critical importance to understand their failure mechanisms. The bond behavior can be studied using different experimental test set-ups; the most commonly used are the single-lap and double-lap direct-shear tests. Although single-lap shear tests are simpler to carry out than double-lap shear tests, the presence of an eccentricity between the pulling and restraining forces leads to a mixed mode fracture process at the interface, which may influence the results. This study investigates the eccentricity effect on the bond behavior of fiber reinforced cementitious …

A Concrete Water Pasteurization Device For Third World Countries, Andrea R. Murchie

Senior Honors Projects, 2010-2019

In the rural areas of South Africa, as well as many other developing countries, people cook food and sterilize their water by heating over open fires. Many times the fires are inside of homes, which more often than not are very small. Children will often be the ones to tend to the fire, out of necessity while parents and other family members are tending to other work and needs.

The purpose of my Senior Honors Project was to design a concrete vessel that can hold water and heat the water to pasteurization (149°F) when exposed to sunlight for an extended …

Manipulation Of Surface Plasmon Resonance In Metal And Alloy Thin Films Using Dielectric Media, Benjamin Dubray Hall

Graduate Theses - Physics and Optical Engineering

Surface plasmon polaritons are coherent electron oscillations that propagate along an interface between a Drude metal and a dielectric medium. The excitation of polaritons is highly dependent on the dielectric properties of the metal, the thickness of the metal, and the optical properties of the dielectric material. First, plasmonic activity is assessed for several thicknesses of silver and nickel chromium under He-Ne incidence. Relationships between film thickness and metal dielectric function are explored in both cases. To manipulate the plasmonic activity at the silver surfaces, two methods are explored. Silver oxide was grown on the surface of the silver films, …

Micro-Raman Investigation Of Residual Stresses In Sic/Sic Composites, Kaitlin Kollins

The University Honors Program

Ceramic Matrix Composites (CMCs) are being developed for use in extreme operating conditions. Specifically, there is interest to replace superalloys with Silicon-Carbide/Silicon-Carbide (SiC/SiC) CMCs in the hot section of gas turbine engines because of their lower densities, high temperature performance, and oxidation resistance. Due to the high temperature processing conditions of SiC/SiC CMCs, there are thermal residual stresses inherent to the material. This study focused on using micro-Raman Spectroscopy on as manufactured SiC/SiC CMCs to measure and investigate the residual stresses within a fiber and the matrix material. Following the silicon Raman active mode at 520 cm-1 and the SiC …

Coercivity Enhancement And Gamma Phase Avoidance Of Alnico Alloys, Li Zhang

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

The promotion of social progress requires greater levels of energy efficiency, quality and productivity. However, these developments usually come at the cost of the environment. Green technologies such as electric vehicles, wind turbine and solar panels are ironically overshadowed by supply limitations and high prices of rare earth elements. Therefore, it is important to find alternative materials to replace those that contain critical elements. Alnico alloys show high magnetization, high Curie temperature (800°C) and good corrosion resistance, making it one of the best candidates to replace neodymium-based magnets used in electric vehicles.

In this thesis, methods controlling shape anisotropy and …

Microstructure And Properties Of Hard And Optically Transparent Hfo2 Films Prepared By High-Rate Reactive High-Power Impulse Magnetron Sputtering, Nai-Wen Pi

Material Science and Engineering Theses - Archive

Hafnium Dioxide (HfO2) has an extraordinary high bulk modulus, high hardness, high chemical stability, high melting point and high thermal stability. This material can be used as protective coatings for application involving high temperature environments. HfO2 films were fabricated on Si using high-rate reactive high-power impulse magnetron sputtering (HiPIMS) using different deposition-averaged target power density and voltage pulse durations t1. Five HfO2 films were prepared with (1) t1 = 25 µs, =7.6 Wcm-2 (T25S7), (2) t1 = 100 µs, =7.2 Wcm-2 (T100S7), (3) t1 = 200 µs, =7.3 Wcm-2 (T200S7), (4) t1 = 200 µs, =18 Wcm-2 (T200S18) and (5) …

Silver Dendrite Based Three-Dimensional Surface Enhanced Raman Scattering (Sers) Substrates, Sandesh Rajkumar Shelke

Material Science and Engineering Theses - Archive

Three-dimensional (3D) hierarchical nanostructures have been considered as one of the most promising surface-enhanced Raman spectroscopy (SERS) substrates because it provides high-density hotspots along the three-dimension directions and high surface areas. In this thesis, we report the synthesis process to develop 3D SERS substrates in thin wall quartz capillary tube on Cu wire. These 3D SERS substrates consist of Ag dendrite, Au-Ag and Pd-Ag bimetallic nanostructures which was synthesized by employing simple galvanic replacement reactions (GRR). In this synthesis process Cu wire which is used as substrate was inserted in the thin walled quartz capillary tube and then AgNO3 was …

Synthesis And Characterization Of Plasmonic-Magnetic Au-Co Multilayered Nanorods, Akshay Hande

Material Science and Engineering Theses - Archive

Au nanoparticles (AuNPs) and superparamagnetic iron oxide nanoparticles (SPIONs), in various forms, are considered as biocompatible and are of great interest for diagnostic imaging and therapeutic applications. Biomedical applications of AuNPs originate from the surface plasmon resonance (SPR) effect. In order to tune the SPR wavelength to the near infrared (NIR) region which is required for deep light penetration for in vivo applications, various types of AuNPs such as nanorods, nanoprisms, nanoshells and nanocages have been developed and investigated. SPIONs have also been explored extensively for biomedical applications, including magnetic cell separation, contrast enhancement agents for magnetic resonance imaging (MRI), …

Energy Transfer And Localization In Molecular Crystals, Mitchell A. Wood

Open Access Dissertations

With the aim of developing new technologies for the detection and defeat of energetic materials, this collection of work was focused on using simulations to characterize materials at extremes of temperature, pressure and radiation. Each branch of the work here is collected by which material response is potentially used as the detectable signal.

Where the chemical response is of interest, this work will explore the possibility of non-statistical chemical reactions in condensed-phase energetic materials via reactive molecular dynamics (MD) simulations. We characterize the response of three unique high energy density molecular crystals to different means of energy input: electric fields …

Customization Of Titanate Nanofiber Bioscaffolds, Jared Hopkins

Biomedical Engineering Undergraduate Honors Theses

In the field of orthopedic devices implant loosening is a major issue resulting in the majority of device failures. These failures result in the need for costly secondary procedures. To reduce device loosening an improved method of tissue anchoring is required. A previously studied titanate nanofiber bioscaffold has been shown to be safely implantable and to contribute to the differentiation of mesenchymal stem cells to osteocytes. Through the customization of both physical and chemical characteristics this titanate nanofiber bioscaffold was fabricated as a potential means to enhance tissue anchoring for use with orthopedic devices. This customization was enabled by acoustic …

Measuring Relative Humidity In Concrete Pavements As A Method To Assess Asr Mitigation Measures, Remington G. Reed

Civil Engineering Undergraduate Honors Theses

Alkali-silica reaction (ASR) in concrete is partly facilitated by available moisture within the concrete. In order to better understand this facilitation and to develop processes for ASR mitigation methods, it is necessary to establish a means of monitoring internal relative humidity (RH) within the concrete. Current procedures for measuring RH are time consuming; requiring several hours of equilibration time and specific external conditions to yield accurate results. In order to better understand RH monitoring, laboratory tests were conducted using commercially available RH probes and different controlled environments. Probes were carefully monitored and calibrated in controlled environments, and laboratory tests on …

A Study On The Synthesis And Properties Of Gold Nanoparticles And Their Applications To Surface Enhanced Raman Spectroscopy, Daniel Robert Soden

Graduate Theses/Dissertations

Surface enhanced Raman substrates represent a critical step in the sensitivity augmentation of Raman spectroscopy, but due to the time and expertise currently required in the synthesis process, they have not been fully realized within an industrial setting. This thesis aims to investigate a new technique in surface enhanced Raman spectroscopy (SERS) substrate fabrication designed to decrease synthesis time and map the most effective growth parameters for a successful Raman intensity boost. Sputter physical vapor deposition was utilized to deposit a gold (Au) layer on an insulating substrate, and annealing treatments were applied to agglomerate the Au atoms into the …

Experimental And Theoretical Analyses Of The Structural, Electronic And Magnetic Properties Of Novel Inverted Core-Shell A-Cr2o3@A-Mxcr2-Xo3-Y (M=Co, Ni, Mn, Fe) Nanoparticles, Mohammad Delower Hossain

Graduate Theses/Dissertations

I used hydrothermal nano-phase epitaxy technique to synthesize well-ordered a-Cr2O3@a-MxCr2-xO3 (M = Co, Ni, Mn, Fe) inverted core-shell nanoparticles (NPs). This resulted in the formation of novel a-MxCr2-xO3 shells having ferromagnetic/ferrimagnetic (FM/FiM) spin ordering and an antiferromagnetic (AFM) a-Cr2O3 core structure. The combined results from Xray diffraction (XRD) and high resolution transmission electron microscoy (HRTEM) provide evidence of the presence of the corundum phase both in the shell and in the core regions. HRTEM results also show a sharp interface exhibiting epitaxial atomic registry of shell atoms over highly ordered core atoms whereas TEM-Energy dispersive spectroscopy analyses show that the …

Investigation Of Optical Properties Of Zinc Oxide Photodetector, Tyler Chism

Graduate Theses and Dissertations

UV photodetection devices have many important applications for uses in biological detection, gas sensing, weaponry detection, fire detection, chemical analysis, and many others. Today’s photodetectors often utilize semiconductors such as GaAs to achieve high responsivity and sensitivity. Zinc oxide, unlike many other semiconductors, is cheap, abundant, non-toxic, and easy to grow different morphologies at the micro and nano scale. With the proliferation of these devices also comes the impending need to further study optics and photonics in relation to phononics and plasmonics, and the general principles underlying the interaction of photons with solid state matter and, specifically, semiconductors. For this …

Stabilization Of Vegetable Oil-Based Quenchants To Thermal-Oxidative Degradation: Experimental Strategy And Effect Of Oxidation On Quenching Performance, Éder Cícero Adão Simêncio, Rosa Lúcia Simêncio Otero, Lauralice De Campos Franceschini Canale, George E. Totten

Mechanical and Materials Engineering Faculty Publications and Presentations

Although petroleum oils continue to be the dominant type of basestock for the formulation of vaporizable quenchants, there is increasing pressure to identify an alternative basestock to address the limitations to their continued use because they are not a renewable basestock and they possess generally poor toxicity and biodegradability properties. Currently the most often cited alternative basestocks are those based on seed oils since they are renewable and usually non-toxic but especially because they are typically readily biodegradable. However, they suffer a critically important deficiency in that they are also typically much less stable to thermal-oxidative degradation than petroleum oils. …

The Effect Of Cure Rate On Glassy Polymer Networks, Kristen M. Van De Voorde

Honors Theses

The formation of glassy polymer networks such as epoxy-amine systems may be altered by varying the temperature ramp rate that is used to cure the system. As a result, the physical and mechanical properties of the network may be changed. This work synthesized the epoxy resins diglycidyl ether of bisphenol A (DGEBA) with the amine curing agent 4,4-diaminodiphenyl sulfone (4,4’-DDS) from 35°C to 180°C using varying temperature ramp rates. Mechanical and structural properties of these samples were then analyzed to determine the effect the different temperature ramp rates had on the formation and properties of the thermoset matrix. These aspects …

Synthesis Of Acceptors For Use In Donor-Acceptor Copolymers And Characterization Of These Polymers, William D. Walker

Honors Theses

In this thesis, a selenium-derivatized acceptor was synthesized to examine the heavy atom effects of selenium on the position of the frontier molecular orbitals (HOMO/LUMO band gap) as opposed to sulfur in a donor-acceptor copolymer for use in light harvesting and detection applications. Over the course of this research, standard operating protocols for ultraviolet-visible (UV-Vis-NIR) and Fourier transform infrared (FT-IR) spectroscopies, as well as cyclic voltammetry (CV) characterization techniques were established. Once synthesized, the polymers were characterized through use of the established characterization protocols. The selenium-derivatized polymer exhibited a bathochromic shift compared to the sulfur analogue, with a solid-state absorption …

Direct Band Gap Gallium Antimonide Phosphide (Gasbxp1-X) For Solar Fuels., Harry Benjamin Russell

Electronic Theses and Dissertations

Photoelectrochemical water splitting has been identified as a promising route for achieving sustainable energy future. However, semiconductor materials with the appropriate optical, electrical and electrochemical properties have yet to be discovered. In search of an appropriate semiconductor to fill this gap, GaSbP, a semiconductor never tested for PEC performance is proposed here and investigated. Density functional theory (DFT+U) techniques were utilized to predict band gap and band edge energetics for GaSbP alloys with low amount of antimony. The overall objective of this dissertation is to understand the suitability of GaSb_xP_1-x alloys for photoelectrochemical water splitting application. Specifically, …

Influence Of Hydrogen Concentration And Distribution On Fracture In Nickel, Arturo Sucre Melfi

Mechanical Engineering Undergraduate Honors Theses

Hydrogen embrittlement is a main factor in the premature failure of metals under stress. Using molecular dynamics (MD) simulations, two models were built in order to study how the presence of hydrogen at interstitial positions within the nickel lattice affects how it fractures. The first model was a 3D single crystal nickel sample, while the other was the same nickel model but with different concentrations and locations of hydrogen positioned at or near the crack tip. Two aspects of fracture were studied and compared between the different simulations: the crack tip velocity and dislocation nucleation from the crack tip. Analysis …