UNT Libraries - 13 Matching Results

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Carbon Nanotubes and Molybdenum Disulfide Protected Electrodes for High Performance Lithium-Sulfur Battery Applications

Description: Lithium-sulfur (Li-S) batteries are faced with practical drawbacks of poor cycle life and low charge efficiency which hinder their advancements. Those drawbacks are primarily caused by the intrinsic issues of the cathodes (sulfur) and the anodes (Li metal). In attempt to resolve the issues found on the cathodes, this work discusses the method to prepare a binder-free three-dimensional carbon nanotubes-sulfur (3D CNTs-S) composite cathode by a facile and a scalable approach. Here, the 3D structu… more
Date: August 2019
Creator: Cha, Eunho
Item Type: Refine your search to only Thesis or Dissertation

Charpy Impact Testing of Twinning Induced Plasticity and Transformation Induced Plasticity High Entropy Alloys

Description: High entropy alloys (HEAs) are a new class of solid solution alloys that contain multiple principal elements and possess excellent mechanical properties, from corrosion resistance to fatigue and wear resistance. Even more recently, twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) non-equiatomic high entropy alloys have been engineered, promising increased strength and ductility as compared to their equiatomic counterparts. However, impact and fracture resistance o… more
Date: August 2019
Creator: Zellner, Samantha R
Item Type: Refine your search to only Thesis or Dissertation

Development of a Novel Grease Resistant Functional Coatings for Paper-based Packaging and Assessment of Application by Flexographic Press

Description: Recent commercial developments have created a need for alternative materials and methods for imparting oil/grease resistance to paper and/or paperboard used in packaging. The performance of a novel grease resistant functional coating comprised of polyvinyl alcohol (PVA), sodium tetraborate pentahydrate (borate) and acetonedicarboxylic acid (ACDA) and the application of said coating by means of flexographic press is presented herein. Application criteria is developed, testing procedures describe… more
Date: August 2004
Creator: Brown, Robert W.
Item Type: Refine your search to only Thesis or Dissertation

Dynamic Deformation and Shear Localization in Friction-Stir Processed Al0.3CoCrFeNi and Fe50Mn30Co10Cr10 High-Entropy Alloys

Description: High entropy alloys (HEAs) are a relatively new class of solid solution alloys that contain multiple principal elements to take advantage of their high configurational entropy, sluggish diffusion, lattice distortion, and the cocktail effect. In recent development, work hardening mechanisms known as twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) have been found active in Al0.3CoCrFeNi (molar fraction) and Fe50Mn30Co10Cr10 (at %) HEA compositions. Friction-stir pr… more
Date: August 2019
Creator: Macdonald, Neil
Item Type: Refine your search to only Thesis or Dissertation

Effect of Silyation on Organosilcate Glass Films

Description: Photoresist stripping with oxygen plasma ashing destroys the functional groups in organosilicate glass films and induce moisture uptake, causing low-k dielectric degradation. In this study, hexamethyldisilazane (HMDS), triethylchlorosilane and tripropylchlorosilane are used to repair the damage to organosilicate glass by the O2 plasma ashing process. The optimization of the surface functionalization of the organosilicate glass by the silanes and the thermal stability of the functionalized surfa… more
Date: August 2004
Creator: Kadam, Poonam
Item Type: Refine your search to only Thesis or Dissertation

Evaluation of hydrogen trapping in HfO2 high-κ dielectric thin films.

Description: Hafnium based high-κ dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in complementary metal oxide semiconductor (CMOS) devices. Hydrogen is one of the most significant elements in semiconductor technology because of its pervasiveness in various deposition and optimization processes of electronic structures. Therefore, it is important to understand the properties and behavior of hydrogen in semiconductors with the final aim of controlling and using … more
Date: August 2006
Creator: Ukirde, Vaishali
Item Type: Refine your search to only Thesis or Dissertation

Extrinsic Doping of Few Layered Tungsten Disulfide Films by Pulsed Laser Deposition

Description: This dissertation tested the hypothesis that pulsed laser deposition (PLD) could be used to create targeted dopant profiles in few layered WS2 films based on congruent evaporation of the target. At the growth temperatures used, 3D Volmer-Weber growth was observed. Increased energy transfer from the PLD plume to the growing films degraded stoichiometry (desorption of sulfur) and mobility. Sulfur vacancies act as donors and produce intrinsic n-type conductivity. Post deposition annealing signific… more
Date: August 2019
Creator: Rathod, Urmilaben Pradipsinh P
Item Type: Refine your search to only Thesis or Dissertation

Mechanical behavior and performance of injection molded semi-crystalline polymers.

Description: I have used computer simulations to investigate the behavior of polymeric materials at the molecular level. The simulations were performed using the molecular dynamics method with Lennard-Jones potentials defining the interactions between particles in the system. Significant effort was put into the creation of realistic materials on the computer. For this purpose, an algorithm was developed based on the step-wise polymerization process. The resulting computer-generated materials (CGMs) exhibit… more
Date: August 2003
Creator: Simoes, Ricardo J. F.
Item Type: Refine your search to only Thesis or Dissertation

Phase Transformation and Elastic Constants in Binary Titanium Alloys: An Atomistic Study

Description: The current understanding of the mechanical properties and deformation behavior of some individual phases in titanium alloys is limited due to the fine scale at which these phases precipitate within the β-phase matrix. The α and ω phases represent the most widely observed phases in titanium alloys depending on the alloy composition and also the heat treatment procedure adopted during processing. The possibility of precipitating ω-phase depends on the content of the β-stabilizers within the syst… more
Date: August 2019
Creator: Salloom, Riyadh Farooq
Item Type: Refine your search to only Thesis or Dissertation

Phase Transformations in Refractory High Entropy Alloys

Description: High entropy alloys (HEAs) based on refractory elements have shown a great potential for high temperature structural applications. In particular, the ones containing Al, exhibits a microstructure similar to the γ-γ' in Ni-based superalloys. While these alloys exhibit impressive strengths at room temperature (RT) and at elevated temperatures, the continuous B2 matrix in these alloys is likely to be responsible for their brittle behavior at RT. Phase stability of five such alloys are studied by t… more
Date: August 2019
Creator: Soni, Vishal
Item Type: Refine your search to only Thesis or Dissertation

Processing-Structure-Property Relationships of Reactive Spark Plasma Sintered Boron Carbide-Titanium Diboride Composites

Description: Sintering parameter effects on the microstructure of boron carbide and boron carbide/titanium diboride composites are investigated. The resulting microstructure and composition are characterized by scanning electron microscopy (SEM), x-ray microscopy (XRM) and x-ray diffraction (XRD). Starting powder size distribution effects on microstructure are present and effect the mechanical properties. Reactive spark plasma sintering introduces boron nitride (BN) intergranular films (IGF's) and their eff… more
Date: August 2019
Creator: Lide, Hunter
Item Type: Refine your search to only Thesis or Dissertation

Topics in micro electromechanical systems: MEMS engineering and alternative materials for MEMS fabrication.

Description: This paper deals with various topics in micro electromechanical systems (MEMS) technology beginning with microactuation, MEMS processing, and MEMS design engineering. The fabrication and testing of three separate MEMS devices are described. The first two devices are a linear stepping motor and a continuous rotary motor, respectively; and were designed for the purpose of investigating the frictional and wear properties of silicon components. The third device is a bi-stable microrelay, in which e… more
Date: August 2004
Creator: Chapla, Kevin
Item Type: Refine your search to only Thesis or Dissertation

Understanding the Micromechanism of Cyclic Loading Behavior of Ultrafine Grained Alloys

Description: In the current study, we have investigated the cyclic loading behavior of conventional as well as novel alloy system exhibiting fine and ultrafine-grained structure. While in case of conventional alloy systems (here aluminum alloy AA5024), the effect of three different grain sizes was investigated. Improvement in fatigue properties was observed with decreasing grain size. The unique microstructure produced via Friction stir processing was responsible for the improved fatigue response. Additiona… more
Date: August 2019
Creator: Shukla, Shivakant
Item Type: Refine your search to only Thesis or Dissertation
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