Materials Science and Engineering Commons^™

First Principles Investigation On Chemical Bonding Of Transition Metal Borides And Carbides, Junshan Wang, Yanchun Zhou

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Fabrication Of Tac-Hfc Ceramics For Ultra-High Temperature Applications, Omar Cedillos, Doni Jayaseelan, Bill Lee

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Poster 4. Microstructure And Mechanical Properties Of Zrb2-Nb Composites, Sun Xin

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Densification And High Temperature Properties Of Zrb2 And Tib2-Based Composites, Neha Gupta, G.B. Raju, Bikramjit Basu

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Microstructure, Tribological Response, And Mechanical Properties Of Fiber Bonded Silicon Carbide Ceramics, M.C. Vera, J. Ramirez, J. Martinez, M. Singh

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Elevated Temperature Deformation Mechanisms In Ta2c, Nicholas De Leon, Billie Wang, Gregory Thompson, Christopher Weinberger

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Effects Of Carbon On The Processing And Thermal Properties Of Hot Pressed Zrb2, Greg Harrington, Greg Hilmas, William Fahrenholtz

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Ultra High Temperature Mechanical Testing Of Zrb2 Ceramics, Eric Neuman, Gregory Hilmas, William Fahrenholtz

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Characterization Of Mechanically Activated Zirconium Diboride (Zrb2) Powders, Mustafa Tuncer

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Ultra-High Temperature Ceramics Research At Afrl, M.K. Cinibulk, T.A. Parthasarathy

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Sintering And Densification Of Uhtcs, Diletta Sciti, Laura Silvestroni, Stefano Guicciardi, Frederic Monteverde

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Sol-Gel Synthesis And Characterization Of Hfb2 Powders, Saranya Venugopal, Anish Paul, Jon Binner, Bala Vaidhyanathan, Peter Brown

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Fabrication, Properties, And Arc-Jet Testing Of Zrb2-Based Composites Containing Short Sic Fibers, Frederic Monteverde, Diletta Sciti, Laura Silvestroni, Davide Alfano, Raffaele Savino

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Interfacial Coatings On Carbon Fibers, N. Baklanova, T. Zima, N. Morozova, I. Igumenov

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Ultra-High Temperature Ceramics: Historic Perspectives And Recent Progress, W.G. Fahrenholtz, G.E. Hilmas

Ultra-High Temperature Ceramics: Materials For Extreme Environmental Applications II

No abstract provided.

Nanocharacterization Of Porous Materials With Atomic Force Microscopy, Yasemin Kutes

Master's Theses

Scanning Probe Microscopy techniques have proven very useful in the investigation of porous nanostructured surfaces. Especially, Atomic Force Microscopy (AFM) has been widely used due to its compatibility with non-conducting surfaces. In particular, AFM often complements other techniques like scanning and transmission electron microscopy by providing quantitative surface information coupled with nanoscale spatial resolution. Its ability to operate in fluid is also important, as this allows researchers to mimic the physiological environment of biological materials and systems. In this work, two main types of porous materials are studied with AFM, including Phosphoric Acid Fuel Cell (PAFC) electrode catalyst layers, and …

Advanced Design Optimization For Composite Structure: Stress Reduction, Weight Decrease And Manufacturing Cost Savings, Shayan Ahmadian

Master's Theses

An injection moldable chopped fiber composite actuator with detailed drawing and tolerances was designed within one year. A vendor was selected and a quote for injection molding tooling cost for production was obtained and the first prototype was built in addition of six months. The risks are identified and material characterization tests are proposed.

The objective of this project was redesigning an aluminum made actuator with a continuous fiber composite for weight saving purposes. After searching the literature and consulting with experts in the field it was concluded that manufacturing costs associated with continuous fiber composite are 3 times as …

Correlation Between 90o Tensile And 90o Flexural Properties For Thermoplastic Based Carbon-Fiber Composites, Amy Lautenbach

Materials Engineering

Thermoplastic matrix composites containing carbon fibers and 4 different resins (TP 1-TP 4) were tested in tension with the fibers at 90 degree to the longitudinal axis following ASTM D 3039-00. The tensile strengths varied from 5.07-13.87 ksi with TP 1 as the strongest, and TP 4 as the weakest. SEM images were taken of the fracture surface of the samples to explore the fiber-matrix interaction. The SEM images showed significantly more wetting of the fibers in the higher strength materials. The SEM images of the two stronger materials showed resin coating the fibers even after fracture while the two …

Cross-Linked Pdms Expansion Due To Submersion In Liquid And Supercritical Co2, Teng Yang

Graduate Theses and Dissertations

Characterization of micro/nano-copper particles impregnated Polydimethylsiloxane (PDMS) submersed in supercritical carbon dioxide (scCO2) was studied. The purpose of this investigation was to advance micro-corrosion sensor technology utilizing PDMS and micro-metal particle composite as the sensing element currently under-development. One of the key challenges encountered was the removal of the native oxides inherently existing on the metal particles. Numerous techniques were experimented with to counter this problem at the UA Engineered Micro/Nano Systems Laboratory (EMNSL), with swell-based protocols being identified as the most promising solution. In terms of compatibility to Micro-electro-mechanical Systems (MEMS) fabrication, CO2 is often used in the release …

Real Time Shrinkage Studies In Photopolymer Films Using Holographic Interferometry, Mohesh Moothanchery, Izabela Naydenova, Viswanath Bavigadda, Suzanne Martin, Vincent Toal

Conference Papers

Polymerisation induced shrinkage is one of the main reasons why photopolymer materials are not more widely used for holographic applications. The aim of this study is to evaluate the shrinkage in an acrylamide photopolymer layer during holographic recording using holographic interferometry. Shrinkage in photopolymer layers can be measured by real time capture of holographic interferograms during holographic recording. Interferograms were captured using a CMOS camera at regular intervals. The optical path length change and hence the shrinkage were determined from the captured fringe patterns. It was observed that the photopolymer layer shrinkage is in the order of 3.5%.

Surface Characterization Of Nephila Clavipes Dragline Silk, Benoit Faugas

All Theses

To design synthetic fibers for extreme applications, many research groups are trying to identify how the structure of natural fibers (such as spider silk) leads to desirable properties such as high tensile strength.
Spider silk is a biological fiber having mechanical properties that exceed those of the best man made fibers in terms of high tensile strength and large extensibility, this combination providing the silk with a large work of rupture. While the bulk structure, composition and properties have been intensively studied elsewhere, this study focuses on elucidating the Nephila clavipes spider dragline silk surface structure and composition, as well …

Effective Dielectric Constant Of Two Phase Dielectric Systems, Vladimir Petrovsky, Piotr Jasinski, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Various theoretical approaches are implemented for electrical characterization of two-phase material systems. Most of these approaches do not include possibility of percolation of the dispersed material. In this article brick wall model is extended on the systems exhibiting percolation. Transition from brick wall geometry to corresponding equivalent circuits provides final equations for effective dielectric constant. Comparison of theoretical results with experimental data shows that developed equations provide good fitting of effective dielectric constant to experimental values. Dielectric constants of both phases and percolation threshold calculated from the fitting match the corresponding experimental values of the phases.

Material Flow And Microstructural Evolution During Friction Stir Spot Welding Of Az31 Magnesium Alloy, W. Yuan, Rajiv S. Mishra, B. Carlson, R. Verma, R. K. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Material flow and local texture evolution during friction stir spot welding (FSSW) of AZ31 magnesium alloy was characterized by varying tool rotation rates. Texture at various locations of the welded region was measured using electron backscatter diffraction (EBSD). Material flow is significantly influenced by tool rotation rate with a conical step spiral pin tool, and FSSW introduces a unique basal fiber texture in the welded region. Results indicate that local texture evolution is dominated by shear deformation through material flow. the tool shoulder applies both shear and compressive deformation to the upper region material; however, the rotating pin introduces only …

Plasma-Assisted Molecular Beam Epitaxial Growth Of Indium Nitride For Future Device Fabrication, Steven Paul Minor

Graduate Theses and Dissertations

The need for energy conservation has heightened the search for new materials that can reduce energy consumption or produce energy by the means of photovoltaic cells. III-nitride alloys show promise for these applications due to their generally good transport properties and ability to withstand high power applications. Along with these, this family of semiconductor alloys has a direct bandgap energy range (0.7-6.2 eV) which spans the entire visible spectrum and encompasses a large portion of the available solar spectrum. Of the three root III-nitride semiconductors, AlN, GaN, and InN, InN has only recently become attainable epitaxially with qualities good enough …

Investigation Of Negative Differential Resistance Phenomena In Quantum Well Heterostructures, Nazariy Andrushchak

Graduate Theses and Dissertations

Increasing interest in entirely new possibilities for quantum mechanical description of carriers transport is becoming more evident with the developing advancements in epitaxial growth technique. Consequently, molecular beam epitaxy (MBE) technique is considered to be the most precise technique that allows the growth of ultra-thin layers of different compositions.

Those structures can be designed to investigate the wave-nature of carriers, which broadens the possibilities in device design and fabrication for a specific area. In this thesis the fundamental study of the real space charge transfer (RST) mechanism that took place in quantum well heterostructures and led to the negative differential …

Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas

Graduate Theses and Dissertations

Stem cell and tissue engineering offer us with a unique opportunity to research and develop new therapies for treating various diseases that are otherwise incurable using traditional medicines. However, development of these new therapies replies upon the establishment of in vitro cell culture and differentiation systems that mimic in vivo microenvironments required for cell-cell and cell-ECM interaction. The development of these cell culture systems depends upon the identification of appropriate biomaterials and cell sources. Biomaterials should be carefully selected and fabricated into scaffolds for supporting cell growth and differentiation. In this study, we explored the fabrication of 3D electrospun nanofiber …

Microencapsulation Of The Non-Steroidal Anti-Inflammatory Drugs Into Biodegradable Polymers Using Supercritical Fluid Technology, Safaa Mohamad Al Mahdi Ali Yousif

Theses

Osteoarthritis is a disease that attacks human bones especially in older people and usually nonsteroidal anti-inflammatory drugs (NSAIDS) are being prescribed for patients with Osteoarthritis. These kinds of drugs usually have low aqueous solubility and in order to have their therapeutic effects, their solubility should be enhanced. The purpose of this study was to find solution for this problem and one way to do that is to reduce the particle size by forming micro particles. In this project, one of these types of drugs ibuprofen (isobutyl-propanoicphenolic Acid) was encapsulated into a polymer (PVP polyvinylpyrrolidone) using supercritical fluid technology (Supercritical CO …

Structural Dna Origami: Engineering Supermolecular Self-Assembly For Nanodevice Fabrication, Craig Marshal Onodera

Boise State University Theses and Dissertations

Two challenges encountered in nanotechnology are the ability to create nanostructures inexpensively and the ability to arrange nanomaterials with a precision commensurate with their size. In nature, nanostructures are created using a bottom-up approach, whereby molecules hierarchically self-assemble into larger systems. Similarly, structural DNA nanotechnology harnesses the programmability, specificity, and structural integrity of DNA to engineer synthetic, self-assembled materials. For example, during scaffolded DNA origami, a long single stranded DNA polymer is artificially folded into nanostructures using short oligonucleotides. Once folded, two- and three-dimensional nanostructures may be decorated with proteins, metallic nanoparticles, and semiconductor quantum dots. Using gold nanoparticles and …

Investigating The Use Of Pozzolans In Portland Cement Concrete And Inorganic Polymer Mortar, Omar Abdelmalek Saleh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of pozzolans offers promising signs for a change in the cement industry. Pozzolan in its natural and artificial forms can be used to improve cement properties or to synthesize new cement. This study investigates the use of pozzolans in portland cement concrete and inorganic polymer mortar (geopolymer mortar).

This thesis is divided into two phases. Phase 1 investigates the use of natural pozzolan as a partial replacement of portland cement in concrete. In this phase two types of class N pozzolan are used separately to develop concrete mixtures contain different percentages of class N pozzolan. Fresh concrete properties …

Characterization And Optimization Of Solution-Derived Chalcogenide Glass Thin Films, Jacklyn Wilkinson

All Theses

Chalcogenide glasses have many unique properties that allow them to be used in a variety of optical applications. Infrared transparency allows them to be used in sensors for molecules that have 'fingerprints' in the 2-25 μm range. By producing amorphous thin films of these materials, they can be incorporated into chemical sensors as planar waveguides and resonators. The goal of this work was to fabricate and characterize solution-derived chalcogenide thin films for use in chemical sensors with a source wavelength between 3-3.5 μm.
The structural and optical properties of the parent bulk glass were characterized and used as reference for …