Materials Science and Engineering Commons^™

An Experimental Investigation On The Trailing Edge Cooling Of Turbine Blades, Zifeng Yang, Hui Hu

Mechanical and Materials Engineering Faculty Publications

An experimental study was conducted to quantify the flow characteristics of the wall jets pertinent to trailing edge cooling of turbine blades. A high-resolution stereoscopic particle image velocimetry (PIV) system was used to conduct detailed flow field measurements to quantitatively visualize the evolution of the unsteady vortices and turbulent flow structures in the cooling wall jet streams and to quantify the dynamic mixing process between the cooling jet stream and the mainstream flows. The detailed flow field measurements were correlated with the adiabatic cooling effectiveness maps measured by using pressure sensitive paint (PSP) technique to elucidate underlying physics in order …

Silica Nanoparticle-Based Coatings With Superhydrophilic And Superhydrophobic Properties, Robert Andrew Fleming

Graduate Theses and Dissertations

Superhydrophilic and superhydrophobic surfaces have potential for implementation into a variety of fields, including self-cleaning surfaces, anti-fogging transparent materials, and biomedical applications. In this study, sandblasting, oxygen plasma treatments, silica nanoparticle films, and a low surface energy fluorocarbon film were employed to change the natural surface wettability of titanium, glass, and polyethylene terephthalate (PET) substrates, with an aim to produce superhydrophilic and superhydrophobic behavior. The effects of these surface modifications are characterized by water contact angles (WCAs), surface wetting stability, surface morphology and roughness, surface elemental composition, and optical transmittance measurements. The results show that stable superhydrophilic and superhydrophobic surfaces …

Design, Fabrication, Testing Of Cnt Based Isfet And Characterization Of Nano/Bio Materials Using Afm, Zhuxin Dong

Graduate Theses and Dissertations

A combination of Carbon Nanotubes (CNTs) and Ion Selective Field Effect Transistor (ISFET) is designed and experimentally verified in order to develop the next generation ion concentration sensing system. Micro Electro-Mechanical System (MEMS) fabrication techniques, such as photolithography, diffusion, evaporation, lift-off, packaging, etc., are required in the fabrication of the CNT-ISFET structure on p-type silicon wafers. In addition, Atomic Force Microscopy (AFM) based surface nanomachining is investigated and used for creating nanochannels on silicon surfaces. Since AFM based nanomanipulation and nanomachining is highly controllable, nanochannels are precisely scratched in the area between the source and drain of the FET where …

Investigation On Thermo-Mechanical Instability Of Porous Low Dielectric Constant Materials, Emil Hyunbae Zin

Material Science and Engineering Dissertations - Archive

This study investigates the structural stability of porous low dielectric constant materials (PLK) under thermal and mechanical load and the influence of contributing factors including porosity as intrinsic factor and plasma damage and moisture absorption as extrinsic factors on thermo-mechanical instability of PLK in advanced Cu/PLK interconnects. For this purpose, a ball indentation creep test technique was developed to examine the thermal and mechanical instability of PLK at relevant load and temperature conditions in the interconnect structure. Our exploration with the ball indentation creep test found that PLK films plastically deforms with time, indicating that viscoplastic deformation does occur under …

First-Principles Studies On N-Type And P-Type Doping In Cuprous Oxide, Qiong Bai

Material Science and Engineering Dissertations - Archive

We have performed studies on n-type and p-type cuprous oxide with and without doping by first principles methods. Generalized Gradient Approximation (GGA) is used for the geometry optimization. The total energy and the final electronic structure calculations are conducted using the nonlocal screened Heyd-Scuseria-Ernzerhof (HSE) hybrid density functionals approach for cuprous oxide. The HSE hybrid density functionals overcome the shortcoming of GGA, which gives a much reliable value of the band gap. The formation energies of native point defects in undoped cuprous oxide have been studied by HSE hybrid functional theory in two conditions, which are vacuum based condition and …

Properties Of Concrete With Tire Derived Aggregate And Crumb Rubber As A Ligthweight Substitute For Mineral Aggregates In The Concrete Mix, Gideon Momanyi Siringi

Material Science and Engineering Dissertations - Archive

Scrap tires continue to be a nuisance to the environment and this research proposes one way of recycling them as a lightweight aggregate which can substitute for mineral aggregates in concrete. Aggregates derived from scrap tires are often referred to as Tire Derived Aggregate (TDA). First, the focus is how much mineral aggregate can be replaced by these waste tires and how the properties of concrete are affected with the introduction of rubber. This is being mindful of the fact that for a new material to be acceptable as an engineering material, its properties and behavior has to be well …

Growth Mechanism And Interface Effects On Microstructure Of Perovskite-Type Barium Titanate-Based Epitaxial Films, Jie He

Material Science and Engineering Dissertations - Archive

This work was motivated and focused on the growth mechanism, microstructures and interfaces of barium titanate, BaTiO3 (BTO), based epitaxial thin films. Transimission electron microscopy (TEM), high resolution TEM (HRTEM), electron diffraction (ED) have been mainly employed in this study for microstructure investigations of BTO-based epitaxial thin films with the assistance of other materials characterization methods, such as X-ray diffraction (XRD), atomic force microscopy (AFM), Nanoindentation testing, etc. As a basic studying model, epitaxial BTO films were first deposited on the (001) MgO substrate using RF magnetron sputtering to provide fundamental knowledge of the film growth for BTO based thin …

Syntheses, Characterization, And Applications Of Injectable Citrate-Based Mussel-Inspired Biodegradable Adhesive (Icmba) Polymers And Hydrogels, Mohammadreza Mehdizadeh

Material Science and Engineering Dissertations - Archive

Tissue adhesives are increasingly gaining more popularity in various areas of biomedical applications. They are utilized as surgical adhesives, as a replacement or adjunct to conventional wound closure and bleeding control techniques such as suturing, as well as in other applications such as tissue engineering and drug delivery.Unfortunately, the existing surgical adhesives are not ideal for wet tissue adhesion required in many surgeries such as those for internal organs. Developing surgical adhesives with strong wet tissue adhesion, controlled degradability and mechanical properties, and excellent biocompatibility has been a significant challenge. Herein, learning from nature, we report a one-step synthesis of …

Prediction Of Compressive Creep Bhaviour In Flexible Polyurethane Foam Over Long Time Scales And At Elevated Temperatures, Conor Briody, Barry Duignan, Stephen Jerrams, Stephen Ronan

Articles

Compressive creep gradually affects the structural performance of flexible polymeric foam material over extended time periods. When designing components, it is often difficult to account for long-term creep, as accurate creep data over long time periods or at high temperatures is often unavailable. This is mainly due to the lengthy testing times and/or inadequate high temperature testing facilities. This issue can be resolved by conducting a range of short-term creep tests and applying accurate prediction methods to the results. Short-term creep testing was conducted on viscoelastic polyurethane foam, a material commonly used in seating and bedding systems. Tests were conducted …

Synthesis And Characterization Of Nanoscale Fluorescent Polymer Films, Maryus Chyasnavichyus

All Dissertations

Performance of the chemical sensing devices is based sensitivity to the targeted analytes and accuracy of the measurements. Of many different types of chemical sensors, fluorescence based sensing devices draw much attention as efficient yet small and straightforward devices, capable of detection of various analytes at extremely small quantities.
Polymeric materials provide support for the fluorescent materials and usually serve as a host for the chromophores, protecting them from harsh environments, and serve as a transport media for the analyte.
In the present study thin fluorescent polymer films, sensitive to the environment are synthesized and studied. Poly(glycidyl methacrylate) was used …

Double Paddle Oscillators For The Mechanical Spectroscopy Of Ion-Solid Interactions, Jason Puls

All Theses

We demonstrated using a double paddle oscillator to measure subsurface defect formation at room temperatures caused by ion implantation. This sensor has a low amount of noise based because of its high quality factors in certain modes. The double paddle oscillator was bombarded with Ar ions under ultra-high vacuum conditions while it was oscillating. The resultant resonant frequency changes were discussed as a method to determine defect formation inside the bulk substrate.

Characterization And Restoration Of Historic Rosendale Cement Mortars For The Purpose Of Restoration, Stephanie Hart

All Theses

Mortar was a very common building material in today's historic sites. Before Portland cement was manufactured at a global level, Rosendale cement was commonly used in these mortars. Over time, these mortars in historic sites have begun to break down and wear away. With Rosendale cement in production again, measures can be taken to restore and repair the historic mortars. However, little testing has been done to establish durability of modern Rosendale cement mortars. This presentation highlights the common mix techniques used at the time, and undergoes experiments to establish general properties and predict future durability. Six different mortar mixes …

Preliminary Investigation Into The Design Of Thermally Responsive Forster Resonance Energy Transfer Colloids, Monte Bedford

All Theses

While nuclear imaging techniques (Magnetic Resonance Imaging, Computed Tomography, and Positron Emission Tomography) have proven effective for diagnosis and treatment of disease in the human body, fluorescence-enhanced optical imaging offers additional benefits. Fluorescent imaging provides high resolution with real-time response, persistent lifetime (hours to days), cell targeting, and transdermal penetration with minimal physical encumbrance. Malignant cells can be targeted by absorbance of exogenous fluorescent nanoprobe contrast agents. Imaging is improved by fluorescent enhancement, especially by energy transfer between attached dyes. Also for use against cancer are heat-active treatments, such as hyperthermal, photothermal, and chemothermal therapies. Helpful to these treatments is …

A Silicon Carbide Based Solid-State Fault Current Limiter For Modern Power Distribution Systems, Erik Darnell Johnson

Graduate Theses and Dissertations

The fault current limiter represents a developing technology which will greatly improve the reliability and stability of the power grid. By reducing the magnitude of fault currents in distribution systems, fault current limiters can alleviate much of the damage imposed by these events. Solid-state fault current limiters in particular offer many improved capabilities in comparison to the power system protection equipment which is currently being used for fault current mitigation. The use of silicon carbide power semiconductor devices in solid-state fault current limiters produces a system that would help to advance the infrastructure of the electric grid.

A solid-state fault …

Plasma Test On Industrial Diamond Powder In Hydrogen And Air For Fracture Strength Study, Rohit Asuri Sudharshana Asuri Sudharshana Chary

UNLV Theses, Dissertations, Professional Papers, and Capstones

Diamonds are the most precious material all over the world. Ever since their discovery, the desire for natural diamonds has been great; recently, the demand has steeply increased, leading to scarcity. For example, in 2010, diamonds worth $50 billion were marketed. This increased demand has led to discovering alternative sources to replace diamonds. The diamond, being the hardest material on earth, could be replaced with no other material except another diamond. Thus, the industrial or synthetic diamond was invented. Because of extreme hardness is one of diamond's properties, diamonds are used in cutting operations. The fracture strength of diamond is …

Recrystallization Kinetics Of 3c Silicon Carbide Implanted With 400 Kev Cesium Ions, Daniel Denell Osterberg

Boise State University Theses and Dissertations

Polycrystalline 3C silicon carbide was implanted at room temperature with 400 keV cesium ions to a dose of 10¹⁶ ions·cm^-2. The samples were then annealed at 600 – 1000°C for 0-48 hours in ultra-high purity argon. The implanted zone of each sample was characterized by transmission electron microscopy and secondary ion mass spectroscopy. It is shown that the implantation resulted in a 217 ± 2 nm amorphous region with microstructural damage extending to approximately 250 nm below the surface. Recrystallization of the amorphous region was observed at 725°C, although minimal densification was observed until ≥ 800°C. Densification …

Fabrication Of Solid Solution Tungsten-Rhenium Alloys By High Energy Ball Milling And Spark Plasma Sintering, Cory C. Sparks

Boise State University Theses and Dissertations

Tungsten-rhenium powders of varying compositions were fabricated by spark plasma sintering (SPS). In initial exploration of the parameter space, W-25 at% Re powders were blended and consolidated by SPS at 1500 to 1900°C with sintering dwell times of 0 to 60 minutes. In addition, the influence of milling was investigated. W-25 at% Re powders were high-energy ball milled at 200 to 400 rpm for 5 hours and consolidated at 1700°C with sintering dwell times of 0 to 60 minutes. The sample densities, grain sizes, porosities, contamination level, and hardness values were measured. The intermetallic content, specifically the fraction of σ-phase, …

Polymeric Eutectic Drug Delivery System, S. Tuntarawongsa, T. Phaechamud

Journal of Metals, Materials and Minerals

Eutectic system is the mixture of at least two substances that suppresses melting point for each of them. The viscosity enhancement of liquid eutectic by polymer addition might increase the viscous environment for retardation of drug release. Typically, there are rare polymers that can dissolve in the liquid eutectic. The aim of this study was to develop the polymeric eutectic delivery system for controlling the drug delivery. Liquid eutectic used as vehicle was prepared by mixing menthol and camphor in various ratios. The obtained lowest viscosity liquid eutectic was used as vehicle in this study. Various polymers were attempted to …

Implementation And Validation Of Fault-Rupture Response Spectrum Analysis Procedure In Csibridge For Bridges Crossing Earthquake Fault Ruptures, Jennifer Evelyn Tures

Master's Theses

This thesis evaluates the application of a simplified analysis procedure as implemented in version 16 of CSiBridge^TM for design of bridges crossing earthquake fault ruptures. The fault-rupture response spectrum analysis (FR-RSA) approximation method has been proved adequate for both straight and curved ordinary bridges, but lacked a comfortable interface to accommodate the method users. Computers and Structure, Inc. has implemented the FR-RSA procedure into CSiBridge^TM, a user-friendly integrated 3-D bridge design software, as an added seismic design feature. By combining the response of the bridge due to the quasi-static displacement from the fault strike-slip rupture and the …

Kinetics And Mechanisms Of Titanium Wire Oxidation, Tanmay P. Engineer

Boise State University Theses and Dissertations

The kinetics and mechanisms of oxidation of titanium wire were assessed using a large test matrix in Ar-20% O₂ at 800 to 1200°C, and N₂-20% O₂ at 1000°C, for 0.5 to 24 hours. The effects of geometry on oxidation were evaluated by investigating the behavior of six high purity Ti wires with diameters varying from 50 to 2000 μm, with an objective of producing hollow TiO₂ tubes.

Oxidation behavior was characterized by measuring oxide thicknesses and morphology by optical microscopy, and the phases were characterized using a combination of SEM and TEM. The kinetics was …