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Department:
Materials Science and Engineering
Decade:
2010-2019
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UNT Scholarly Works
Temperature-dependent structural heterogeneity in calcium silicate liquids
Date: December 7, 2010
Creator: Benmore, Chris J.; Weber, J. K. R.; Wilding, Martin C.; Du, Jincheng & Parise, John B.
Description: This article discusses temperature-dependent structural heterogeneity in calcium silicate liquids. X-ray diffraction measurements performed on aerodynamically levitated CaSiO3 droplets have been interpreted using a structurally heterogeneous liquid-state model. When cooled, the high-temperature liquid shows evidence of the polymerization of edge shared Ca octahedra. Diffraction isosbestic points are used to characterize the polymerization process in the pair-distribution function. This behavior is linear in the high-temperature melt but exhibits rapid growth just above the glass transition temperature around 1.2Tg. The heterogeneous liquid interpretation is supported by molecular-dynamics simulations which show the CaSiO3 glass has more edge-shared polyhedra and fewer corner shared polyhedra than the liquid model.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc107770/
Tungsten Carbide and Possible Military Applications
Date: April 14, 2011
Creator: Brice, David & Collins, Peter
Description: This poster discusses research on tungsten carbide and possible military applications. Tungsten carbide (WC) ceramics are extremely hard and exhibit great potential for use in military application. The purpose of this project is to show that tungsten carbide (WC) is a more effective material than Kevlar or steel when used for body armor. Tungsten carbide possesses a high measure of hardness that indicates a high resistance to deformation. Also, the methods of production, namely Pulsed Current Activated Sintering (PCAS), can increase these natural properties. To conclusively prove that WC can be used as body armor components, the material must be tested by firing armor piercing munitions at samples of the material.
Contributing Partner: UNT Honors College
Permallink:digital.library.unt.edu/ark:/67531/metadc86697/
Laser Surface Engineering for Improved Biocompatibility of Orthopedic Biomaterials
Date: April 19, 2012
Creator: Dahotre, Sanket; Paital, Sameer & Banerjee, Rajarshi
Description: This poster discusses research on laser surface engineering for improved biocompatibility of orthopedic biomaterials. Abstract: Even now, 90 percent of humans above the age of 40 show signs of bone degeneration as a result of society taking a turn towards more active lifestyles. This has led to a dramatic increase in the number of hip replacement surgeries. Implants today top out at around 15 years if the recipient follows a strict lifestyle protocol. As a younger demographic is now requiring prosthetic implantation surgery, it has become necessary for the implants to last longer while allowing recipients to carry on their lifestyles. These lifestyles can be hampered by flaws in current implant materials today such as low bio compatibility and varying material strength which can lead to effects such as inability to walk and insomnia caused by unbearable pain. In order to address such issues, it is becoming important to find orthopedic implant materials that do not have the previously discussed flaws. Titanium is a material that is widely being studied for strength similar to bone. However, titanium lacks in bio chemical compatibility as an orthopedic bio material. This is due to cells not recognizing the foreign metal implant due to ...
Contributing Partner: UNT Honors College
Permallink:digital.library.unt.edu/ark:/67531/metadc86824/
Modified embedded atom method study of the mechanical properties of carbon nanotube reinforced nickel composites
Date: March 11, 2010
Creator: Uddin, Jamal; Baskes, Michael I.; Srivilliputhur, Srinivasan; Cundari, Thomas R., 1964- & Wilson, Angela K.
Description: This article discusses modified embedded atom method study of the mechanical properties of carbon nanotube reinforced nickel composites. Abstract: We report an atomistic simulation study of the behavior of nanocomposite materials that are formed by incorporating single-walled carbon nanotubes (SWCNTs), with three different diameters, and a multiwalled carbon nanotube (MWCNT) into a single-crystal nickel matrix. The interactions between carbon and nickel atoms are described by a modified embedded atom method potential. Mechanical properties of these nanocomposite materials are predicted by atomistic calculations and compared with that of fcc nickel and pristine CNTs. Our simulations predict that all Ni/CNT composites studied in this work are mechanically stable. Their elastic properties depend on the volume fraction and diameter of embedded CNTs. The single-crystal Young's modulus (E₁₁) of Ni/SWCNT composites exhibit a large increase in the direction of CNTs alignment compared to that of a single-crystal nickel. However, a moderate but gradual decrease is seen for E₂₂ and E₃₃ in the transverse directions with increase in CNT diameters. As a consequence, Ni/SWCNTs show a gradual decrease for the polycrystalline Young's, bulk and shear moduli with the increasing CNT diameters and volume fractions. These reductions, although moderate, suggest that enhancement of mechanical properties for ...
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc107769/
Laser Machining of Structural Ceramics: An Integrated Experimental and Numerical Approach for Surface Finish
Date: March 2, 2013
Creator: Vora, Hitesh D. & Dahotre, Narendra B.
Description: This poster received 1st place in the 2013 Graduate Exhibition in the Engineering category. Abstract: High energy lasers emerged as an innovative and potential industrial tool to fabricate complex shapes on structural ceramics which is otherwise difficult using conventional machining techniques. However, obtaining a desired surface finish at higher material removal rate during laser machining of structural ceramics is still a critical issue. In this situation, the better understanding of various physical phenomena such as heat transfer, fluid flow, recoil pressure, Marangoni convection, and surface tension and its influence on the evolution of typical surface topography during laser machining could be more helpful. In light of this, this study was attempted to present the state of the art of laser machining of alumina using an integrated experimental and computational approach. A multistep computational model based on COMSOL™ Multiphysics was developed to study the effect of various physical phenomena on the generation of surface topography for various laser machining conditions. Furthermore, this process model can be used as a handy tool for the process engineers to configure the process variables (laser power, scanning speed, pulse rate, size of overlap) to obtain the specified quality characteristics. The surface topography of laser machined ...
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc152429/