Open Access. Powered by Scholars. Published by Universities.®

Materials Science and Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2008

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 271 - 275 of 275

Full-Text Articles in Materials Science and Engineering

Modeling And Simulations Of Diphasic Composites For Development Of High Energy Density Dielectrics, Sandeep K. Patil Jan 2008

Modeling And Simulations Of Diphasic Composites For Development Of High Energy Density Dielectrics, Sandeep K. Patil

Doctoral Dissertations

"This research is focused on diphasic dielectric composites for high energy density storage applications in pulsed power and power distribution systems. Composite materials are particularly attractive because they can synergistically combine high permittivity with high breakdown strength of the individual phases. Energy density, which captures permittivity and dielectric breakdown strength as vital material parameters, dominates this research challenge. Avenues for increasing the effective permittivity and breakdown strength may be found by gaining fundamental understanding of the response of diphasic dielectrics to an applied electric field. Improved understanding of these characteristics will ultimately lead to dielectrics with increased energy storage densities. …

Go to article

Thin Film Techniques For The Fabrication Of Nano-Scale High Energy Density Capacitors, James N. Reck Jan 2008

Thin Film Techniques For The Fabrication Of Nano-Scale High Energy Density Capacitors, James N. Reck

Doctoral Dissertations

Dielectric thin films of either TiO₂ or BaTiO₃ were sputtered in O₂/Ar plasmas on Si wafers to thicknesses ranging from approximately 25 to 200 nm with patterned Ni or Pt electrodes sputtered in Ar plasmas at thicknesses from about 20 to 250 nm to form nano-capacitors. Statistical design of experiments (DOE) was used to determine the effects of the deposition power, plasma composition, and deposition temperature on the measured electrical properties of the nano-capacitors. Additional tests to determine the effects of the dielectric and electrode thickness on the measured dielectric responses of the devices were also undertaken. Characterization was performed …

Go to article

Geological Sequestration Of Carbon Dioxide By Hydrous Carbonate Formation In Steelmaking Slag, C. Hank Rawlins Jan 2008

Geological Sequestration Of Carbon Dioxide By Hydrous Carbonate Formation In Steelmaking Slag, C. Hank Rawlins

Doctoral Dissertations

"The formation of carbonate solids from the alkaline earth oxide phases in steelmaking slag was investigated in dry and aqueous conditions as a vehicle for carbon dioxide sequestration. The goal of this research was to determine the process conditions that would increase the kinetics of the carbonate formation process under hydrous conditions, enabling direct removal of carbon dioxide from steelmaking offgas"--Abstract, page iv.

Go to article

Densification, Microstructure, And Mechanical Properties Of Zirconium Diboride Based Ultra-High Temperature Ceramics, Sumin Zhu Jan 2008

Densification, Microstructure, And Mechanical Properties Of Zirconium Diboride Based Ultra-High Temperature Ceramics, Sumin Zhu

Doctoral Dissertations

"The first part of this dissertation was aimed at studying the densification of ZrB₂ ceramics by pressureless sintering techniques. Various processes have been applied to coat ZrB₂ powders with polymer precursors, which were used to produce C after charring. After sintering at 1900⁰C, relative density increased of ~70% for uncoated ZrB₂ to >99% for ZrB₂ coated with at least 1.0 wt% C. Thermodynamic analysis suggested that C reacted with and removed oxide impurities (ZrO₂ and B₂O₃) that were present on the ZrB₂ particle surfaces, which promoted densification by minimizing grain coarsening"--Abstract, page iv.

Go to article

The Effects Of Nanoscale Disorder On The Paramagnetic To Ferromagnetic Transition In Melt-Spun Gadolinium And Gadolinium Iron Alloys, Justin Gary Bohnet Jan 2008

The Effects Of Nanoscale Disorder On The Paramagnetic To Ferromagnetic Transition In Melt-Spun Gadolinium And Gadolinium Iron Alloys, Justin Gary Bohnet

Honors Program Theses

As nanoscale science continues to flourish, scientists strive to understand how structure and order (or disorder) on the nanoscale contribute to macroscopic properties, such as magnetism. This study examines alloys of gadolinium and iron that have been nanostructured through the process of melt-spinning. The result was a two-part system consisting of small (~70 nm) gadolinium grains surrounded by an amorphous gadolinium and iron matrix. Measurements of the samples’ DC magnetization and AC susceptibility were performed. By looking at the paramagnetic to ferromagnetic transition in the materials, the critical exponents were obtained and used to classify and understand how the addition …

Go to article

First Prev