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Polyethylene-layered double hydroxide and montmorillonite nanocomposites: Thermal, mechanical and flame retardance properties.

Description: The effect of incorporation two clays; layered double hydroxides (LDH) and montmorillonite layered silicates (MLS) in linear low density polyethylene (PE) matrix was investigated. MLS and LDH were added of 5, 15, 30 and 60 weight percent in the PE and compounded using a Brabender. Ground pellets were subsequently compression molded. Dispersion of the clays was analyzed using optical microscopy, SEM and XRD. Both the layered clays were immiscible with the PE matrix and agglomerates formed with i… more
Date: May 2008
Creator: Kosuri, Divya
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Microstructure Evolution and Mechanical Response of Material by Friction Stir Processing and Modeling

Description: In this study, we have investigated the relationship between the process-microstructure to predict and modify the material's properties. Understanding these relationships allows the identification and correction of processing deficiencies when the desired properties are not achieved, depending on the microstructure. Hence, the co-relation between process-microstructure-properties helped reduce the number of experiments, materials & tool costs and saved much time. In the case of high entropy all… more
Date: August 2022
Creator: Gupta, Sanya
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

In-situ Analysis of the Evolution of Surfaces and Interfaces under Applied Coupled Stresses

Description: To study the effect of the substrate support on the nanoscale contact, three different regimes, i.e., graphene on rigid (ultra-crystalline diamond) and on elastic (Polydimethylsiloxane) supports and free-standing graphene, were considered. The contribution of the graphene support to the mechanical and electrical characteristics of the graphene/metal contact was studied using the conductive atomic force microscopy (AFM) technique.The results revealed that the electrical conductivity of the graph… more
Date: August 2020
Creator: Lee, Ji Hyung
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Design and Manufacture of Molding Compounds for High Reliability Microelectronics in Extreme Conditions

Description: The widespread use of electronics in more avenues of consumer use is increasing. Applications range from medical instrumentation that directly can affect someone's life, down hole sensors for oil and gas, aerospace, aeronautics, and automotive electronics. The increased power density and harsh environment makes the reliability of the packaging a vital part of the reliability of the device. The increased importance of analog devices in these applications, their high voltage and high temperature … more
Date: December 2016
Creator: Garcia, Andres
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Materials Approaches for Transparent Electronics

Description: This dissertation tested the hypothesis that energy transferred from a plasma or plume can be used to optimize the structure, chemistry, topography, optical and electrical properties of pulsed laser deposited and sputtered thin-films of ZnO, a-BOxNy, and few layer 2H-WS2 for transparent electronics devices fabricated without substrate heating or with low substrate heating. Thus, the approach would be compatible with low-temperature, flexible/bendable substrates. Proof of this concept was demons… more
Date: December 2021
Creator: Iheomamere, Chukwudi E.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

First Principle Calculations of the Structure and Electronic Properties of Pentacene Based Organic and ZnO Based Inorganic Semiconducting Materials

Description: In this thesis, I utilize first principles density functional theory (DFT) based calculations to investigate the structure and electronic properties including charge transfer behaviors and work function of two types of materials: pentacene based organic semiconductors and ZnO transparent conducting oxides, with an aim to search for high mobility n-type organic semiconductors and fine tuning work functions of ZnO through surface modifications. Based on DFT calculations of numerous structure comb… more
Date: May 2012
Creator: Li, Yun
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Defect Behaviors in Zinc Oxide and Zinc Titanates Ceramics from First Principles Computer Simulations

Description: ZnO and ZnO-TiO2 ceramics have intriguing electronic and mechanical properties and find applications in many fields. Many of these properties and applications rely on the understanding of defects and defect processes in these oxides as these defects control the electronic, catalytic and mechanical behaviors. The goal of this dissertation is to systematically study the defects and defects behaviors in Wurtzite ZnO and Ilmenite ZnTiO3 by using first principles calculations and classical simulatio… more
Date: December 2016
Creator: Sun, Wei
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Workfunction tuning of AZO Films Through Surface Modification for Anode Application in OLEDs.

Description: Widespread use of organic light emitting diodes (OLEDs) in solid state lighting and display technologies require efficiency and lifetime improvements, as well as cost reductions, inclusive of the transparent conducting oxide (TCO). Indium tin oxide (ITO) is the standard TCO anode in OLEDs, but indium is expensive and the Earth's reserve of this element is limited. Zinc oxide (ZnO) and its variants such as aluminum-doped ZnO (AZO) exhibit comparable electrical conductivity and transmissivity to … more
Date: August 2016
Creator: Jha, Jitendra
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Processing and Shape-Setting of Shape Memory Alloys for Small Satellite Antennas

Description: In this study, four different NiTi-based shape memory alloys (SMAs) compositions were processed, shape-set, and characterized to evaluate their effectiveness as SMA actuation component for satellite antennas. Three of the compositions were commercially available NiTi wires (90°C Flexinol® actuator NiTi wire and Confluent ADB SE508 NiTi wire), NiTi SM495 plates (ATI Specialty Alloys and Components) and the other composition was in house lab-produced NiTiCu plate. Different shape-setting techniqu… more
Date: December 2022
Creator: Al Jabri, Nehal Ahmed Mubarak
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Orientation, Microstructure and Pile-Up Effects on Nanoindentation Measurements of FCC and BCC Metals

Description: This study deals with crystal orientation effect along with the effects of microstructure on the pile-ups which affect the nanoindentation measurements. Two metal classes, face centered cubic (FCC) and body centered cubic (BCC, are dealt with in the present study. The objective of this study was to find out the degree of inaccuracy induced in nanoindentation measurements by the inherent pile-ups and sink-ins. Also, it was the intention to find out how the formation of pile-ups is dependant upon… more
Date: May 2008
Creator: Srivastava, Ashish Kumar
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Substrate Nanotopography and Stiffness Modulation of Cell Behavior

Description: The physical characteristics (i.e., nanostructure and stiffness) of the extracellular matrix where cells reside have been shown to profoundly affect numerous cellular events in vivo and also been employed to modulate cell behavior in vitro, yet how these physical cues regulate cell behavior is still elusive. Therefore, we engineered a variety of nanotopographies with different shapes and dimensions, and investigated how the nanotopographical cue, through focal adhesions-cytoskeleton-nucleus pat… more
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Date: May 2019
Creator: Wang, Kai
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Crystallization and Lithium Ion Diffusion Mechanism in the Lithium-Aluminum-Germanium-Phosphate Glass-Ceramic Solid Electrolytes

Description: NASCION-type lithium-aluminum-germanium-phosphate (LAGP) glass-ceramic is one of the most promising solid electrolyte (SEs) material for the next generation Li-ion battery. Based on the crystallization of glass-ceramic material, the two-step heat treatment was designed to control the crystallization of Li-ion conducting crystal in the glass matrix. The results show that the LAGP crystal is preferred to internally crystalize, Tg + 60%∆T is the nucleation temperature that provides the highest ion… more
Date: May 2021
Creator: Kuo, Po Hsuen
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Processing-Structure-Property Correlation for Additively Manufactured Metastable High Entropy Alloy

Description: In the present study both fusion based - laser powder bed fusion (LPBF), and solid state - additive friction stir deposition (AFSD) additive manufacturing processes were employed for the manufacturing of a metastable high entropy alloy (HEA), Fe40Mn20Co20Cr15Si5 (CS-HEA). A processing window was developed for the LPBF and AFSD processings of CS-HEA. In case of LPBF, formation of solidification related defects such as lack of fusion pores (for energy density ≤ 31.24 J/mm3) and keyhole pores (for… more
Date: August 2022
Creator: Agrawal, Priyanshi
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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