Materials Science and Engineering Commons^™

Magneto-Optics And Magneto-Transport Studies On Thin Films For Sensor Applications, Kaida Yang

Dissertations, Theses, and Masters Projects

Recent progress and interest have bought considerable effort to bear on the synthesis and opportunities of magnetic thin films in different fields. There are applications in many fields, including remote sensing, waveguide applications, hard drive applications, etc. at the College of William and Mary, we have focused on utilizing magnetic thin films in some of these applications and are deeply involved in the optimization process of the thin films.

Joining And Hermetic Sealing Of Silicon Carbide Using Iron, Chromium, And Aluminum Alloys, Andrew Morgan

Theses and Dissertations

Silicon Carbide (SiC) is increasingly gaining attention as a potential fuel cladding material, on account of its favorable thermo-mechanical and neutronic properties. The major limitations of such a cladding is currently associated with joining and hermetic sealing. The work presented here investigated the use of Al, Cr and Fe metals and a specialized alloy (FeCrAl) to achieve hermetic sealing of SiC tubes as well as a joining technology of SiC. Major part of solving this issue requires addressing joining of ceramic and metallic components, which are largely dissimilar in both thermal and mechanical properties. Preliminary experiments to bond SiC with …

Environmental Degradation Of Nano Enhanced Polymers In Low Earth Orbit, Mohammed Jaradat

Electronic Theses and Dissertations

No abstract provided.

Co2 Sequestration In Cement-Based Materials During Mixing Process Using Carbonated Water And Gaseous Co2, Jacek Kwasny, P. A. Muhammed Basheer, Mark I. Russell, William Doherty, Kieran Owens, Neil Ward

International Conference on Durability of Concrete Structures

This paper presents selected findings from a recently completed research project, aimed at the investigation of CO₂ sequestration in cement-based materials during the early stages of hydration when the cement paste is being mixed. Portland cement pastes were carbonated during the mixing process, using both carbonated water and gaseous CO₂, and their properties were compared to the control non-carbonated mix. All mixes were prepared in a purpose-designed chamber that permitted carbonated water and gaseous CO₂ to be mixed with the cementbased materials during the mixing process, without losses of CO₂ to the external environment. Temperature …

Influence Of Organic Inhibitor On Corrosion Resistance Of Steel In Simulated Concrete Pore Solution, Jingshun S. Cai, C. C. Chen, J. Z. Liu, J. P. Liu

International Conference on Durability of Concrete Structures

Organic corrosion inhibitor is one of lower cost technologies that limit the deterioration of concrete structures. The influence of a newly prepared organic corrosion inhibitor on the corrosion behavior of carbon steel in simulated concrete pore solution was investigated by polarization curves, electrochemical impedance spectroscopy, and so on. The effect of organic corrosion inhibitors on concrete working performance was also studied. The results show that the corrosion rate decreases with the concentration of inhibitor increase; when the content of inhibitor up to 1.5% versus water, the oxide film was completely passive. Organic corrosion inhibitor had no effect on work performance.

Freeze Thaw Durability Of Internally Cured Concrete Made Using Superabsorbent Polymers, Wesley A. Jones, W. Jason Weiss

International Conference on Durability of Concrete Structures

The use of superabsorbent polymers (SAPs) to produce internally cured concrete has been shown to be effective in reducing the potential for restrained shrinkage cracking of high performance concrete mixtures. However, not much is known regarding the freeze–thaw durability of concrete mixtures that incorporate SAPs for internal curing (IC). When SAP particles desorb (or partially desorb) the “water” (pore fluid) they contain for the purposes of IC, some believe that the void space created by these particles can provide enough empty voids to accommodate the additional volume caused by water expansion upon freezing. This paper investigates the freeze–thaw durability of …

Electric-Field Induced Ferromagnetic Phase In Paraelectric Antiferromagnets, Maya D. Glinchuk, Eugene A. Eliseev, Yijia Gu, Long-Qing Chen, Venkatraman Gopalan, Anna N. Morozovska

Materials Science and Engineering Faculty Research & Creative Works

The phase diagram of a quantum paraelectric antiferromagnet EuTiO₃3 under an external electric field is calculated using Landau-Ginzburg-Devonshire theory. The application of an electric field E in the absence of strain leads to the appearance of a ferromagnetic (FM) phase due to the magnetoelectric (ME) coupling. At an electric field greater than a critical field, E_cr, the antiferromagnetic (AFM) phase disappears for all considered temperatures, and FM becomes the only stable magnetic phase. The calculated value of the critical field is close to the values reported recently by Ryan et al. [Nat. Commun. 4, 1334 (2013)10.1038/ncomms2329] …

A Novel Injectable Borate Bioactive Glass Cement As An Antibiotic Delivery Vehicle For Treating Osteomyelitis, Hao Ding, Cunju Zhao, Xu Cui, Yifei Gu, Weitao Jia, M. N. Rahaman, Yang Wang, Wenhai Huang, Changqing Zhang

Materials Science and Engineering Faculty Research & Creative Works

Background: A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. Materials and Methods: The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. Results: …

Practical Aspects Of Modern And Future Permanent Magnets, R.W. Mccallum, L. H. Lewis, Ralph Skomski, M. J. Kramer, I. E. Anderson

Ralph Skomski Publications

The mandate to reduce greenhouse gases will require highly efficient electric machines for both power generation and traction motor applications. Although permanent magnet electric machines utilizing Nd2Fe14B-based magnets provide obvious power-to-weight advantages over induction machines, the limited availability and high price of the rare earth (RE) metals make these machines less favorable. Of particular concern is the cost and supply criticality of Dy, a key RE element that is required to improve the high-temperature performance of Nd-based magnetic alloys for use in generators and traction motors. Alternatives to RE-based alloys do exist, but they currently lack the energy density necessary …

Agen/Bsen 344: Biological And Environmental Transport Processes—A Peer Review Of Teaching Project Benchmark Portfolio, Shadi F. Othman

UNL Faculty Course Portfolios

The course I am providing a portfolio for is BSEN/AGEN 344 which is a required course for all our undergraduate students. The Department provides an assessment for the course to align itself with the ABET's Accreditation Process. I taught the course in Spring 2012 adapting a new Team Based Learning Approach. I have three main objective from my portfolio: (1) refine my methods in documenting the linkage between my course goals and assessment measures, (2) document the efficacy of team based learning approach, (3) refine team based learning approach for the current course and adapt the approach to future courses, …

The Environmental Performance Of Biobased Resin Within Phenolic-Urethane Nobake Binders: A Feasibility Study, Ian David Morgan Williams

Dissertations and Theses @ UNI

The objectives of this research were to investigate the discovery and development of a biobased nobake binder resin for use within the foundry industry toward improved energy efficiency and environmental performance. The performance of polysaccharides within biobased resins was evaluated using industry-accepted methods and standards such as cure rate, tensile-strength development, and casting performance based upon step cone core results. Biobased nobake resins comprised of polysaccharide raw materials cure at a rate that is comparable to conventional nobake sand binders. Upon reaching stripping time, the development of biobased resin reveals a rapid increase in tensile strength, reaching 80% of its …

Correlation Between The Microstructure And Mechanical Properties Of Irradiated Fe-9cr Ods, M. Swenson, C. Dolph, J. Wharry

Materials Science and Engineering Faculty Publications and Presentations

The growing global demand for energy will increasingly call upon fusion reactors and Generation IV nuclear fission reactors to supply safe and reliable energy worldwide. Ferritic/martensitic (F/M) alloys are leading candidates for structural components in these reactors because of their high strength, dimensional stability, and low activation. In novel reactor concepts, these materials will be subject to extreme operating conditions, accumulating doses of irradiation up to a few hundred displacements per atom (dpa) at temperatures as high as 600°C. Oxide dispersion strengthened (ODS) F/M alloys containing a dispersion of Y-Ti-0 nanoclusters have been developed to operate at even higher temperatures.

3d Printing Technology Using High Viscous Materials-Synthesis Of Functional Materials And Fabrication Of 3d Metal Structure, Seongik Hong

Open Access Theses & Dissertations

In the 3D printing technology, the research for using various materials has been performing. In this research work, 3D printable high viscous materials are suggested as one of the solutions for problems in the traditional 3D printing technology.

First, Cu-Ag coreshell was synthesized as a functional material. In terms of the reaction rate, reaction rate limiting step was defined as a fundamental research, and then prepared Cu-Ag coreshell was printed and analyzed. Second, the high viscous Cu paste was prepared and then metal 3D printed structure was fabricated by using new printing method.

In the synThesis of Cu-Ag coreshell, different …

Effect Of Solid Solutions And Second Phases On The Thermal Conductivity Of Zirconium Diboride Ceramics, Gregory John Kenneth Harrington

Doctoral Dissertations

"The research presented in this dissertation is focused on the thermal conductivity (k) of ZrB₂ ceramics. The goal was to develop a better understanding of how various solid solutions and second phases affect the thermal and electrical transport in ZrB₂, with a focus on the effect of C, W, and ZrC. The first study showed C additions improved densification and it was proposed that the reduction of boria was the impetus for this result. Boron carbide was formed by the reaction of excess C with reduced B and its formation was mitigated by the addition of ZrH …

Dissolution Behavior Of Phosphate Glasses, Li Na Ma

Doctoral Dissertations

"The solubility of phosphate glasses in aqueous solutions can be tailored through compositional control to obtain a wide range of ion release rates required for a variety of applications. The principal objective of this dissertation is to advance the understanding of the dissolution behavior of phosphate glasses in aqueous environments.

Two families of glasses, sodium-iron phosphate (NFP) glasses and sodium-calcium phosphate (NCP) glasses, were evaluated. The dissolution behavior depends on the phosphate anions that constitute the glass structure and the associated metal (Me) cations. The phosphate glass structure, defined by the distribution and average size of phosphate anions and depending …

Repeated Load Relaxation Testing Of Pure Polycrystalline Nickel At Room Temperature Using Nanoindentation, D. E. Stegall, M. A. Mamun, B. Crawford, A, A. Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

We present the results of repeated relaxation tests using nanoindentation to derive the activation volume of the dislocation velocity and the ratios of the dislocation density and dislocation velocity. An experimental technique, based on classical uniaxial relaxation experiments, was developed to establish a constant strain during repeated load relaxation transients and then to calculate the stiffness of unloading, and therefore the hardness, across the transients with acceptable results. We found that the activation volume of the dislocation velocity from our nanoindentation methodology was in good agreement when compared to the same reported for uniaxial experiments. © 2014 AIP Publishing LLC.

Polarization Of Bi2te3 Thin Film In A Floating-Gate Capacitor Structure, Hui Yuan, Kai Zhang, Haitao Li, Hao Zhu, John E. Bonevich, Helmut Baumgart, Curt A. Richter, Qiliang Li

Electrical & Computer Engineering Faculty Publications

Metal-Oxide-Semiconductor (MOS) capacitors with Bi₂Te₃ thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of the Bi₂Te₃ thin film while the gate voltage sweeps. The temperature-dependent capacitance measurement indicates that the activation energy is about 0.33 eV for separating the electron and hole pairs in the bulk of Bi₂Te₃, and driving them to either the top or bottom surface of the thin film. Because of the fast polarization speed, potentially excellent …

Stm Study Of Pulsed Laser Assisted Growth Of Ge Quantum Dot On Si(1 0 0)-(2 × 1), Ali Orguz Er, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Ge quantum dot formation on Si(1 0 0)-(2 × 1) by nanosecond pulsed laser deposition under laser excitation was investigated. Scanning tunneling microscopy was used to probe the growth mode and morphology. Excitation was performed during deposition using laser energy density of 25-100 mJ/cm ². Faceted islands were achieved at a substrate temperature of ∼250 °C only when using laser excitation. The island morphology changes with increased laser excitation energy density although the faceting of the individual islands remains the same. The size of the major length of islands increases with the excitation laser energy density. A purely electronic …

First-Principles Investigations Of Iron-Based Alloys And Their Properties, Krista Renee Limmer

Doctoral Dissertations

"Fundamental understanding of the complex interactions governing structure-property relationships in iron-based alloys is necessary to advance ferrous metallurgy. Two key components of alloy design are carbide formation and stabilization and controlling the active deformation mechanism. Following a first-principles methodology, understanding on the electronic level of these components has been gained for predictive modeling of alloys.

Transition metal carbides have long played an important role in alloy design, though the complexity of their interactions with the ferrous matrix is not well understood. Bulk, surface, and interface properties of vanadium carbide, VC_x, were calculated to provide insight for the carbide …

The Structure And Properties Of Ternary Zinc Phosphate Glasses For Optical Applications, Charmayne Elizabeth Smith

Doctoral Dissertations

"This dissertation focuses on the properties and structures of ternary zinc phosphate glasses that have recently been investigated as substrates for femto-second (fs) laser writing. Although these glasses have potential for use as optical substrates, their poor chemical properties limit their applications. In this work, ternary zinc phosphate glasses were studied to find compositions with enhanced chemical durability and the properties and structures of the investigated glasses are reported.

Paper 1 and Paper 2 include the first systematic studies of the properties, structures of zinc aluminophosphate (ZAP) glasses and phase relationships in the ZnO-Al₂O₃-P₂O₅ system, respectively. Adding alumina to a …