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Full-Text Articles in Engineering
Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera
Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera
Doctoral Dissertations
In this work, a systematic computational study directed toward developing a molecular-level understanding of gas adsorption and diffusion characteristics in nano-porous materials is presented. Two different types of porous adsorbents were studied, one crystalline and the other amorphous. Physisorption and diffusion of hydrogen in ten iso-reticular metal-organic frameworks (IRMOFs) were investigated. A set of nine adsorbents taken from a class of novel, amorphous nano-porous materials composed of spherosilicate building blocks and isolated metal sites was also studied, with attention paid to the adsorptive and diffusive behavior of hydrogen, methane, carbon dioxide and their binary mixtures. Both classes of materials were …
Nonlinear Adaptive Diffusion Models For Image Denoising, Ajay Kumar Mandava
Nonlinear Adaptive Diffusion Models For Image Denoising, Ajay Kumar Mandava
UNLV Theses, Dissertations, Professional Papers, and Capstones
Most of digital image applications demand on high image quality. Unfortunately, images often are degraded by noise during the formation, transmission, and recording processes. Hence, image denoising is an essential processing step preceding visual and automated analyses. Image denoising methods can reduce image contrast, create block or ring artifacts in the process of denoising. In this dissertation, we develop high performance non-linear diffusion based image denoising methods, capable to preserve edges and maintain high visual quality. This is attained by different approaches: First, a nonlinear diffusion is presented with robust M-estimators as diffusivity functions. Secondly, the knowledge of textons derived …
The Effect Of Processing Parameters On Barrier Properties Of Polymers, Russell Louis Hallman Jr.
The Effect Of Processing Parameters On Barrier Properties Of Polymers, Russell Louis Hallman Jr.
Doctoral Dissertations
The intent of this work was to learn if polyethylene could be made with predictable water transfer rates by control of the microstructure. A series of films were formed from three different polyethylenes with a range crystallinities using melt pressing, a controlled cooling rate, and subsequent heat treatments. The samples were tested on a novel device called the polymer characterization device that measures the water transfer flux as a function of temperature. The samples’ morphology was examined using differential gradient column, differential scanning calorimetry, Fourier transform infrared microscopy, wide-angle X-ray diffractions, small-angle X-ray scattering, and small angle light scattering, and …
Novel Ceria-Zirconia-Yttria Mesostructures: Synthesis, Characterization, Diffusional Studies And The Effects Of Morphology On Their Properties, Alma Cordova Morales
Novel Ceria-Zirconia-Yttria Mesostructures: Synthesis, Characterization, Diffusional Studies And The Effects Of Morphology On Their Properties, Alma Cordova Morales
All Dissertations
Ceria-zirconia-yttria (CZY) mixed oxides are used as catalyst supports for three-way catalysts for automotive exhaust emission control and in solid oxide fuel cells. By improving the morphology of CZY mesopores it is possible to reduce the sintering of supported noble metals and enhance overall catalyst lifetime and performance. However, limited studies have been published on the synthetic control of the morphology of CZY materials and the effects that CZY pore geometry has on catalyst operation.
To create optimized CZY catalyst supports, novel mesoporous CZY oxides were synthesized via classical sol-gel and evaporation induced self-assembly (EISA) methods, obtaining mesostructures that exhibited …
A Microfluidic Platform To Quantify Spatio-Temporal Diffusion Of Chemo-Gradients Within 3d Scaffolds: Applications In Axonal Biology, Michael A. Sawonik
A Microfluidic Platform To Quantify Spatio-Temporal Diffusion Of Chemo-Gradients Within 3d Scaffolds: Applications In Axonal Biology, Michael A. Sawonik
ETD Archive
Axonal outgrowth and guidance play an important role in wiring the developing and regenerating nervous system. The critical role of biomolecular gradients in facilitating this axonal sensitivity and directionality along specific trajectories needs to be elucidated for designing effective therapeutic treatments under injury or disease conditions. However, previous in vitro approaches based on micropipette assay or gel-turning assay proved to be unsuitable or inefficient for precise generation and quantification of diffusive gradients. In this study, we utilized a microfluidic device to generate and quantify physiologically-relevant biomolecular gradients in a simple and reliable manner. Using a combination of computational and experimental …
Interdiffusion And Impurity Diffusion In Magnesium Solid Solutions, Catherine Kammerer
Interdiffusion And Impurity Diffusion In Magnesium Solid Solutions, Catherine Kammerer
Electronic Theses and Dissertations
Magnesium, being lightweight, offers potential to be developed into extensive structural applications. The transportation segment has particular interest in Mg and Mg alloy for applications where reduced vehicle weight is proportional to increased fuel efficiency. Aluminum and zinc are two of the most common alloying elements in commercial Mg alloys. They improve the physical properties of Mg through solid solution strengthening and precipitation hardening. Diffusion plays a key role in the kinetics of and microstructural development during solidification and heat treatment. However, there is limited diffusion data available for Mg and Mg alloys. In particular, because Al is monoisotopic, tracer …
Interdiffusion Reaction Between Uranium-Zirconium And Iron, Young Joo Park
Interdiffusion Reaction Between Uranium-Zirconium And Iron, Young Joo Park
Electronic Theses and Dissertations
U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction of the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 630, 650 and 680°C for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and …
Effect Of Exhaust Gas Recirculation And Combustible Oxygen Mass Fraction On Emission Index Of Nox For Counterflow Methane/Air Diffusion Flames, Mugdha S. Sane
Effect Of Exhaust Gas Recirculation And Combustible Oxygen Mass Fraction On Emission Index Of Nox For Counterflow Methane/Air Diffusion Flames, Mugdha S. Sane
Open Access Theses
Exhaust gas recirculation has been proven to be an effective method of reducing emissions of oxides of nitrogen (NOx) from internal combustion engines. The present study validates this effect through flame simulations using detailed chemistry. Counterflow methane/air diffusion flames were simulated in one dimension in physical space using GRI-Mech 3.0 detailed chemistry mechanism, thermal, and transport data. The influence of Exhaust Gas Recirculation (EGR) on the flame structure and NOx emissions was studied by selecting higher than ambient inlet temperature and by varying the composition of the oxidizer stream. The Combustible Oxygen Mass Fraction (COMF), which represents the fraction of …
Plasma-Enhanced Atomic Layer Deposition Of Ruthenium-Titanium Nitride Mixed-Phase Layers For Direct-Plate Liner And Copper Diffusion Barrier Applications, Adam James Gildea
Plasma-Enhanced Atomic Layer Deposition Of Ruthenium-Titanium Nitride Mixed-Phase Layers For Direct-Plate Liner And Copper Diffusion Barrier Applications, Adam James Gildea
Legacy Theses & Dissertations (2009 - 2024)
Current interconnect networks in semiconductor processing utilize a sputtered TaN diffusion barrier, Ta liner, and Cu seed to improve the adhesion, microstructure, and electromigration resistance of electrochemically deposited copper that fills interconnect wires and vias. However, as wire/via widths shrink due to device scaling, it becomes increasingly difficult to have the volume of a wire/via be occupied with ECD Cu which increases line resistance and increases the delay in signal propagation in IC chips. A single layer that could serve the purpose of a Cu diffusion barrier and ECD Cu adhesion promoter could allow ECD Cu to occupy a larger …