Materials Science and Engineering Commons^™

Redistribution Of Manganese Ion Implanted In Silicon, Arun Kumar Shunmugavelu

Electronic Theses and Dissertations

Ion implantation and the subsequent redistribution of manganese atoms in Czochralski Silicon (Cz-Si) and Floating Zone Silicon (Fz-Si) due to thermal annealing between 300 C and 1000 C is studied using Secondary Ion Mass Spectroscopy. The samples ion implanted at 340 C showed multiple peak formation above 900 C. This was not observed for the samples ion implanted at room temperature. Cz-Si and Fz-Si showed similar redistribution profiles.

Microwave Synthesis Of Nanocrystalline Hydroxy Apatite And Comparison Of Its Biomechanical Properties With Tio2 Structures, Saurabh Verma

Electronic Theses and Dissertations

Nanocrystalline hydroxyapatite (HAp) powder of size 10-20 nm was synthesized applying microwave radiation using calcium nitrate tetrahydrate and sodium phosphate dibasic anhydrous as the starting materials. Microwave power of 600 W and Ca/P ratio of 1.66 in the starting chemicals served as the major factors in the synthesis of nanocrystalline HAp powder. Phase composition and evolution were studied using X-ray diffraction (XRD) technique. Morphology, agglomeration and particle-size of the synthesized powder were studied using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. Energy Dispersive Spectrum (EDS) was used to determine the elemental composition of the powder. Thermal properties …

Film Growth Of Novel Frequency Agile Complex-Oxide Piezoelectric Material, Bindu Sreeramakavacham

Electronic Theses and Dissertations

Piezoelectric materials are well known for their applications in surface (SAW) and bulk acoustic wave (BAW) devices such as oscillators, resonators and sensors. Quartz has been the main material used in such applications. Ternary calcium gallium germanate (CGG) structure-type materials, so-called langasites, recently emerged as very promising because of their piezoelectric properties superior to quartz. This thesis discusses the growth of langasite-type La3Ga5.5Ta0.5O14 (LGT) films by liquid phase epitaxy (LPE) technique and their chemical and structural characterization. In addition, the different techniques suitable for the growth of LGT are discussed and compared. To adjust the materials properties for given applications, …

Development And Application Of A High-Resolution Thin-Film Probe, Shaohua Li, Kuifeng Hu, Daryl G. Beetner, James L. Drewniak, James N. Reck, Matthew O'Keefe, Kai Wang, Xiaopeng Dong, Kevin P. Slattery

Electrical and Computer Engineering Faculty Research & Creative Works

This paper documents the development, characterization, and application of a high-resolution thin-film magnetic-field probe. Probe diameter ranged from 5-μm to 100-μm. The 100-μm probe exhibits a 250-7μm improvement in spatial resolution compared to a conventional loop probe, measured at a height of 250 μm over differential traces with a 118-μm spacing. Electric field rejection was improved using shielding and using a 180-degree hybrid junction to separate common-mode (electric field) and differential-mode (primarily magnetic field) coupling. A network analyzer with narrow band filtering was used to detect the relatively weak signal from the probe and to allow detection of phase information. …

Interfacial And Capillary Pressure Effects On The Thermal Performance Of Wax/Foam Composites, Mohammad Rajab Almajali, Khalid Lafdi, Shadab Shaikh

Chemical and Materials Engineering Faculty Publications

A numerical investigation study was performed to study the phase change behavior of wax/foam composite encapsulated in an aluminum casing. Two types of foam materials, namely, aluminum and carbon, were infiltrated with paraffin wax. The progress of melt interface and temperature distribution within the encapsulated composite was analyzed using computational fluid dynamics software (CFD). A two-energy equation model was implemented in the CFD software through the use of user-defined function (UDF). Interfacial effects influencing the heat transfer process at the casing-composite junction and between the wax-foam surfaces within the composite were addressed through the use of separate UDF. In addition, …

Oxygen Plasma Treatment And Deposition Of Cnx On A Fluorinated Polymer Matrix Composite For Improved Erosion Resistance, Christopher Muratore, Andras Korenyi-Both, John E. Bultman, A. R. Waite, John G. Jones, T. M. Storage, Andrey A. Voevodin

Chemical and Materials Engineering Faculty Publications

The use of polymer matrix composites in aerospace propulsion applications is currently limited by insufficient resistance to erosion by abrasive media. Erosion resistant coatings may provide necessary protection; however, adhesion to many high temperature polymer matrix composite (PMC) materials is poor. A low pressure oxygen plasma treatment process was developed to improve adhesion of CNx coatings to a carbon reinforced, fluorinated polymer matrix composite. Fullerene-like CNx was selected as an erosion resistant coating for its high hardness-to-elastic modulus ratio and elastic resilience which were expected to reduce erosion from media incident at different angles (normal or glancing) relative to the …

Interaction Between Metal Fission Products And Triso Coating Materials, Clemens Heske

Fuels Campaign (TRP)

This project focuses on the chemical bonding and interface formation of metal fission products with the coating materials used in tri-isotropic (TRISO) fuel particles for gas-cooled reactors. By combining surface- and bulk-sensitive spectroscopic methods, intermediate chemical phases at the interface, intermixing/ diffusion behavior, and the electronic interface structure as a function of material (metal and coating materials) and temperature are examined.

In the past year, emphasis was placed on a detailed analysis and description of the Cs/SiC interface formation process.

Heating Methods And Detection Limits For Infrared Thermography Inspection Of Fiber-Reinforced Polymer Composites, Jeff R. Brown, H. R. Hamilton

Publications

The use of fiber-reinforced polymer (FRP) composites to strengthen existing civil infrastructure is expanding rapidly. Many FRP systems used to strengthen reinforced concrete are applied using a wet lay-up method in which dry fibers are saturated on site and then applied to the surface. This research investigated using infrared thermography (IRT) as a nondestructive evaluation (NDE) tool for detecting air voids and epoxy-filled holes in FRP systems bonded to a concrete substrate. Four small-scale specimens with FRP thicknesses ranging from 1 to 4 mm (0.04 to 0.16 in.) containing fabricated defects were constructed and inspected in a laboratory setting. Three …

Irradiation And Metal-Containing Conjugated-Polymer Nanocomposites, Frank D. Blum, Zhe-Fei Li, Sunil K. Pillalamarri, Massimo F. Bertino

Chemistry Faculty Research & Creative Works

In recent years, there has been considerable interest in inorganic/organic hybrid materials that combine the desirable properties of both classes. These composite materials may find significant application in a variety of applications such as sensors, memory and energy conversion, to name just a few. In our laboratories, we have recently made a series of studies on the production of polymer nanofibers and their composites with nanometals. Much of this work has focused on the production of polyaniline (PANI) nanofibers that have been made from one-pot syntheses in aqueous solutions where the polymerization was influenced by -radiation1 or UV-radiation.2 in the …

Properties Of Alkaline-Resistant Calcium-Iron-Phosphate Glasses, Jiawanjun Shi

Masters Theses

"The physical properties and alkaline corrosion resistant properties of calcium-iron-phosphate glasses were studied. The addition of Fe₂O₃ decreases the thermal expansion coefficient and increases the glass fiber's Young's modulus in comparison with the addition of CaO. Bulk glass dissolution behavior in alkaline Lawrence solution was studied by weight loss experiments, Raman spectroscopy, and analytical scanning electron microscopy. The corrosion of glass powder in NaOH solution was studied by X-ray diffraction, infrared spectroscopy and high pressure liquid chromatography. The results show that the dissolution rate decreases when the phosphate chain length decreases. Calcium oxide can improve the glass durability in high …

Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt

Faculty Publications

A near-field room temperature scanning magnetic probe microscope has been developed using a laminated magnetoelectric sensor. The simple trilayer longitudinal-transverse mode sensor, fabricated using Metglas as the magnetostrictive layer and polyvinylidene fluoride as the piezoelectric layer, shows an ac field sensitivity of 467±3μV∕O_e in the measured frequency range of 200Hz–8kHz. The microscope was used to image a 2mm diameter ring carrying an ac current as low as 10⁻⁵A. ac fields as small as 3×10⁻¹⁰T have been detected.

Age Strengthening Of Gray Cast Iron: Alloying Effects And Kinetics Study, Thottathil Viswanathan Anish

Masters Theses

"Age strengthening of gray cast iron has become a critical issue with metal casters trying to optimize their process for the closest conformance to properties. This necessitated more robust and precise methods to predict age strengthening. Most foundries use age strengthening behavior to cast at hight carbon equivalents to facilitate smaller gating systems. Also, it is well known in the casting industry that the tool life improves with aging. Hence these foundries require a model to predict aging behavior and accelerate the mechanism from days to hours. This research focuses on the methods of composition adjustments to control aging properties, …

Process Development And Applications Of A Dry Film Photoresist, Phaninder R. Kanikella

Masters Theses

"In this study, dry film photoresist was patterned using UV lithography and the sidewall profile was optimized to achieve vertical sidewalls. Sidewall verticality of dry film is very important for better pattern transfer"--Abstract, page iv.

Formation Of In- (2×1) And In Islands On Si (100) - (2×1) By Femtosecond Pulsed Laser Deposition, M. A. Hafez, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The growth of indium on a vicinal Si (100) - (2×1) surface at room temperature by femtosecond pulsed laser deposition (fsPLD) was investigated by in situ reflection high-energy electron diffraction (RHEED). Recovery of the RHEED intensity was observed between laser pulses and when the growth was terminated. The surface diffusion coefficient of deposited In on initial two-dimensional (2D) In- (2×1) layer was determined. As growth proceeds, three-dimensional In islands grew on the 2D In- (2×1) layer. The RHEED specular profile was analyzed during film growth, while the grown In islands were examined by ex situ atomic force microscopy. The full …

The Effect Of The Size Of Pinning Centres On The Critical Current Density In High-Temperature Superconductors, Salama Bakhit Sowaidan Al-Neaimi

Theses

Superconductor materials that have no resistance to the flow of electricity are one of the last great frontiers of scientific discovery.

Superconductivity in these materials occurs particularly in the copper-oxide (CuO₂) planes. However, since these materials are type-II superconductors, magnetic fields can penetrate these materials in quantized amounts of flux called vortices without completely destroying superconductivity, but producing some resistance, due to vortex motion. In order to overcome the resistance problem, vortices must be pinned to prevent their motion and hence eliminate the resistance.

In this work study we have performed extensive numerical simulations to study the effect …

Microstructures And Viscoelastic Properties Of Anisotropic Magnetorheological Elastomers, Lin Chen

Articles

The microstructures and viscoelastic properties of anisotropic magnetorheological elastomers were investigated in this paper. The measurement results show that their mechanical properties are greatly dependent on the magnetic flux density applied in preparation. A finite-column model was proposed to describe the relations between the microstructures and the viscoelastic properties. The simulation results agree well with the experimental results.

Investigation On Magnetorheological Elastomers Based On Natural Rubber, Lin Chen

Articles

Magnetorheological Elastomers (MR Elastomers or MREs) are a kind of novel smart material, whose mechanical, electrical, magnetic properties are controllable under applied magnetic fields. They have attracted increasing attentions and broad application prospects. But conventional MREs are limited to wide applications because their MR effects and mechanical performances are not high enough. This paper aims to optimize the fabrication method and to fabricate good natural rubber based MREs with high modulus by investigating the influences of a variety of fabrication conditions on the MREs performances, such as matrix type, external magnetic flux density, and temperature, plasticizer and iron particles. Among …

The Effect Of The Rate Of Precursor Production On The Purity And Aggregation Morphology Of Nanoparticulate Zinc Oxide, Grainne Duffy, Suresh Pillai, Declan Mccormack

Articles

The synthesis of zinc oxide through the decomposition of a solid oxalate precursor was
investigated. It was found that the rate of preparation of the precursor had a quantitative effect on
the morphology and extent of surface ligation of particles produced; contrary to our expectations,
it was found that the slow combination of reagents led to a less pure product. It has been
determined that this time dependence mimics the variation of reactant ratios. Zinc oxide particles
were produced from a number of reactant ratios, and were characterised by TEM, XRD, FT-IR
and DSC. It was found that the size …

Fracture Toughness Of Ceramic Moulds For Investment Casting With Ice Patterns, Qingbin Liu, Ming-Chuan Leu, Von Richards

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ice patterns can be used to make ceramic investment moulds for metal castings. Owing to the characteristics of ice, the ceramic mould must be made at subzero temperatures and consequently, requires a different formulation than shells built at room temperature. Success of this process depends greatly on the fracture toughness of mould materials. The present paper describes the experimental results of fracture toughness of mould materials processed from different compositions. The Taguchi method was used to reduce the trial runs. The parameters considered included the ratio of fibre containing fused silica and aluminosilicate powders, the volume of binder and the …

Increasing Energy Efficiency Through Improvements In Ladle Materials And Practices, Kent D. Peaslee, Semen Naumovich Lekakh, Jeffrey D. Smith, Mangesh Vibhandik

Materials Science and Engineering Faculty Research & Creative Works

Steel foundry ladle practices play an important role in total energy efficiency of melting as well as influence casting quality. Extensive heat losses in the ladle could be associated with excessive superheating of the melt before tap which increases energy consumption, promotes oxidation of the melt and increases refractory consumption. A high cooling rate of the liquid metal in the ladle could also cause casting quality instability. The overall ladle heat balance and components of heat losses were analyzed using FLUENT and FACTSAGE software and validated with experimental data from both the UMR foundry and industrial foundries. The purpose of …

Growth Of Mc3t3-El Pre-Osteoblasts On Borate Containing Glasses & Growth Of Osteoblastic Cells On 13-93 Glass Scaffolds, Agatha Dwilewicz

Opportunities for Undergraduate Research Experience Program (OURE)

Three borate-based glasses, compositions designated 1B, 2B, and 3B, with B₂0₃ levels of 15, 31, and 46 mole percent (Table 1), respectively, were tested for their effects on the growth of MC3T3-El mouse pre-osteoblastic cells under physiological fluid conditions. Silicate type 45S5 glass was used as a control for comparison. Independently, the biocompatibility of recently developed silicate-based porous 13-93 bioactive glass scaffolds was tested; Saos-2 human osteosarcoma cell line was used. Tests performed for the two studies included: contact assays of cell growth at the glass interface, chemical analysis of borate released into the culture medium, quantitative …

Preparation Of Bioactive Glasses With Controllable Degradation Behavior And Their Bioactive Characterization, Aihua Yao, Deping Wang, Qiang Fu, M. N. Rahaman, Wen-Hai Huang

Materials Science and Engineering Faculty Research & Creative Works

Bioactive glasses and ceramics have been widely investigated for bone repair because of their excel-lent bioactive characteristics. However, these biomaterials undergo incomplete conversion into a bone-like material, which severely limits their biomedical application. In this paper, borosilicate bioac-tive glasses were prepared by traditional melting process. The results showed that borosilicate glasses possessed high biocompatibility and bioactivity. In addition, when immersed in a 0.02 mol/L K2HPO4 solution, particles of a borate glass were fully converted to HA. The desirable conversion rate to HA may be achieved through the adjustment of the B2O3/SiO2 ratio. The results of XRD and FTIR analysis indicated …

An Evaluation Of Supercritical Drying And Peg/Freeze Drying Of Waterlogged Archaeological Wood, Eric Schindelholz, Robert Blanchette, Desmond C. Cook, Michael Drews, Steve Hand, Benjamin Held, Joel Jurgens, Betty Seifert

Physics Faculty Publications

This study was undertaken to evaluate the physical effects of drying waterlogged archaeological wood using supercritical carbon dioxide as compared to air drying and the popular polyethylene glycol (PEG)/freeze drying method. Previous studies have shown supercritical drying to be a potentially advantageous alternative to current methods of drying waterlogged wood through reduced processing time, minimal shrinkage, and increased success for reversibility. Samples in the form of blocks and planks of a few centimeters in size were prepared from two archaeological waterlogged wood sources and grouped into three treatment sets: one for air drying, one for PEG/freeze drying, and the other …

Mode Suppressed Tem Cell Design For High Frequency Ic Measurements, Shaowei Deng, David Pommerenke, Todd H. Hubing, James L. Drewniak, Daryl G. Beetner, Dongshik Shin, Sungnam Kim, Hocheol Kwak

Electrical and Computer Engineering Faculty Research & Creative Works

TEM cells or GTEM cells can be used to evaluate the radiated emissions of integrated circuits (ICs). The applicable frequency bandwidth of a TEM cell is limited due to the resonances of higher order modes. This paper describes how a TEM cell can be modified to extend the frequency range without changing the test topology. Several methods are proposed and implemented to suppress the higher order modes. The magnetic field coupling and electric field coupling are evaluated for the new design. The frequency bandwidth of the modified TEM cell is extended from original 1 GHz to 2.5 GHz.

Process Development For The Formation Of Post-Bonding Biorecognition Layers In Microfluidic Biosensors, Martin G. Perez, Phaninder R. Kanikella, James N. Reck, Chang-Soo Kim, Matthew O'Keefe

Electrical and Computer Engineering Faculty Research & Creative Works

Formation of the biorecognition layers within microfluidic sensor channels must be done after the completion of the channel structure since these layers cannot withstand the wafer bonding temperature. We propose a new post-bonding immobilization process to prepare the enzyme layers within microfluidic channels of electrochemical biosensors. An array of Pt vertical electrodes is electroplated using a SU-8 mold. The cured SU-8 is then removed by plasma etching to expose the Pt electrode and to define the fluidic channel cavity simultaneously. An array of enzyme posts is formed on the Pt surface by either electropolymerizing or photopolymerizing enzyme precursor solutions injected …

Friction Stir Processing Of Cast Magnesium Alloys, Timothy A. Freeney

Masters Theses

"This thesis investigates the feasibility and benefits of using friction stir processing as a thermo-mechanical microstructural modification tool for local property enhancement or casting repair of magnesium alloys, specifically high strength EV31A and WE43"--Abstract, page iv.