Synthesis Of Amorphous Hydrogenated Boron Carbide From Orthocarborane Using Argon Bombardment: A Reaxff Molecular Dynamics Study,
2019
Missouri State University
Synthesis Of Amorphous Hydrogenated Boron Carbide From Orthocarborane Using Argon Bombardment: A Reaxff Molecular Dynamics Study, Nirmal Baishnab
Graduate Theses/Dissertations
In this study, the synthesis process of a-BxC:Hy using argon bombardment from the orthocarborane precursor was modeled by using reactive molecular dynamics (MD). Utilizing the MD simulations, the formation of free radicals as a result of ion bombardment was identified and quantified. Then, the densification process that is aided by the mixture of free radicals and orthocarborane was analyzed. The densification process by creating the initial structure composed of free radicals and orthocarborane with active sites created by partially removing some of the hydrogen atoms from the icosahedral cage was also modelled. Overall, a better understanding of …
Braze For Ceramic And Ceramic Matrix Composite Components,
2019
Missouri University of Science and Technology
Braze For Ceramic And Ceramic Matrix Composite Components, Sean E. Landwehr, Scott Nelson, Jeremy Lee Watts, Greg Hilmas, William Fahrenholtz, Derek Scott King
Materials Science and Engineering Faculty Research & Creative Works
In some examples, a technique may include positioning a first part comprising a ceramic or ceramic matrix composite and a second part comprising a ceramic or a CMC adjacent to each other to define a joint region at the interface of the first part and the second part. In some examples, the joint region may be heated using at least one of a laser or a plasma arc source to heat the joint region to an elevated temperature. The first and second parts may be pressed together and cooled to join the first and second parts at the joint region. …
Methods Of Use And Manufacture Of Silver-Doped, Nano-Porous Hydroxyapatite,
2019
Missouri University of Science and Technology
Methods Of Use And Manufacture Of Silver-Doped, Nano-Porous Hydroxyapatite, Cheol-Woon Kim, Richard K. Brow
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
A silver-doped, nano-porous hydroxyapatite material is provided that can be utilized to capture radioactive iodine, 129I. Methods of using the silver-doped, nano-porous hydroxyapatite material to remove radioactive iodine, and methods of manufacturing the material are also provided.
Bioprinting With Human Stem Cell-Laden Alginate-Gelatin Bioink And Bioactive Glass For Tissue Engineering,
2019
Missouri University of Science and Technology
Bioprinting With Human Stem Cell-Laden Alginate-Gelatin Bioink And Bioactive Glass For Tissue Engineering, Krishna C. R. Kolan, Julie A. Semon, Bradley Bromet, D. E. Day, Ming-Chuan Leu
Biological Sciences Faculty Research & Creative Works
Three-dimensional (3D) bioprinting technologies have shown great potential in the fabrication of 3D models for different human tissues. Stem cells are an attractive cell source in tissue engineering as they can be directed by material and environmental cues to differentiate into multiple cell types for tissue repair and regeneration. In this study, we investigate the viability of human adipose-derived mesenchymal stem cells (ASCs) in alginate-gelatin (Alg-Gel) hydrogel bioprinted with or without bioactive glass. Highly angiogenic borate bioactive glass (13-93B3) in 50 wt% is added to polycaprolactone (PCL) to fabricate scaffolds using a solvent-based extrusion 3D bioprinting technique. The fabricated scaffolds …
Erosion Resistance Of Tungsten-Carbide Coatings For Steel Pipes In Fluid Catalytic Cracking Units,
2019
California Polytechnic State University, San Luis Obispo
Erosion Resistance Of Tungsten-Carbide Coatings For Steel Pipes In Fluid Catalytic Cracking Units, Davis Vannasing, Jennifer Hulfachor
Materials Engineering
In petroleum processing, the flow of catalyst readily leads to erosion of piping in a fluid catalytic cracking unit. Advances in coating materials and processes necessitate a re-evaluation of current protection methods. Commercially available tungsten-carbide (WC) claddings and nanostructured WC-W CVD coatings were investigated as potential alternative erosion-resistant coatings. Erosion tests by solid particle impingement were conducted on 2 variations of claddings and 1 variation of WC-W coatings following ASTM standard G76. A36 steel coupons were used as reference samples. For statistical validation, 2-3 replications of the tests were performed for the claddings and WC-W coating. Testing was conducted using …
Investigation Of Copper Infiltration Alloys For Use In Metal Matrix Composite Drill Bits,
2019
California Polytechnic State University, San Luis Obispo
Investigation Of Copper Infiltration Alloys For Use In Metal Matrix Composite Drill Bits, Samuel J. Stueland, Timothy P. Markiewicz
Materials Engineering
A newly developed copper-based alloy, P98-X1 was tested for compressive strength to predict qualitative performance compared to MF53, F-Bronze, CuNiSn, and CuMnNi for use as the infiltration alloy in metal matrix composite (MMC) drill bits. Ingots of each alloy were cast using an arc furnace and cut into compression testing samples using wire electrical discharge machining (EDM). The alloys were selected for testing based on solid solution strengthening coefficient and melting point. Five of each alloy were compression tested to determine yield strength of the infiltration alloy. Yield strength was determined using a 0.002mm displacement offset from the linear elastic …
Nano Fab Lab 63,
2019
California Polytechnic State University, San Luis Obispo
Nano Fab Lab 63, Brian K. Deemer, Josh Clemons, Nick Brodine, Delaney Fitzsimmons
Mechanical Engineering
Lawrence Livermore National Laboratories (LLNL) has several steps in the production process for ceramic nanofiber tubes that they would like to improve - electrospinning, cutting, rolling, sealing and heat treating. We undertook the challenge to deliver LLNL with a semi-automated process that efficiently integrates the steps of cutting, rolling, and sealing to save time and improve control over end dimensions. In this document, we discuss the technical background of the manufacturing steps currently followed to create nanofiber tubes, identify which steps are incorporated in our prototype and explain how they will interface with one another, define the design requirements, present …
Fracture Toughness Improvement Of ����� Ceramics By Grain Size Control And Ductile Phase Reinforcement,
2019
Washington University in St. Louis
Fracture Toughness Improvement Of ����� Ceramics By Grain Size Control And Ductile Phase Reinforcement, Kesong Wang
McKelvey School of Engineering Graduate Student Theses & Dissertations
This study used grain size control and ductile phase reinforcement to improve fracture toughness of ����� ceramics. Alpha alumina particles of 100 nm, 0.5-1 micrometers, and 10 micrometers were coated with 1-5 nm nickel by electroless nickel plating (ENP). The coated powders were consolidated at 1200℃-1500℃ by spark plasma sintering (SPS). The sintered samples were annealed at 1100 oC for 1.5 hours and 10 hours to determine the effect of post sintering annealing on hardness and fracture toughness. Density of the samples were measured by the standard Archimedes method using a 5 mL pycnometer. Hardness values were determined by Vickers …
Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides.,
2019
University of Louisville
Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides., Babajide Patrick Ajayi
Electronic Theses and Dissertations
Clean energy production and storage are two of the most significant challenges in the 21st century currently limited by the discovery and development of new and advanced materials. Complex oxides and alloys made using earth-abundant elements will play a crucial role in technology development moving forward, however, current preparation techniques are limited by their inability to produce complex oxides and alloys with precise composition control at fast timescales. A concept was proposed to produce mixed metal oxides with composition control through the oxidation of liquid precursors via plasma oxidation. It was hypothesized that the oxidation process can be completed …
Synthesis And Characterization Of Dielectric And Multiferroic Nanocrystalline Transition Metal Oxide Materials And Nanocomposites,
2019
CUNY Graduate Center
Synthesis And Characterization Of Dielectric And Multiferroic Nanocrystalline Transition Metal Oxide Materials And Nanocomposites, Frederick A. Pearsall
Dissertations, Theses, and Capstone Projects
Nanocrystalline transition metal oxides with unique chemical, physical, magnetic and dielectric properties have very broad applications, ranging from photocatalysis, capacitor energy storage and 4-state memory. Frequency stable, high permittivity nanocomposite capacitors produced under mild processing conditions offer an attractive replacement to MLCCs derived from conventional ceramic firing. In one project reported herein, 0-3 nanocomposites were prepared using BaTiO3 (barium titanate, BTO) nanocrystals, suspended in a poly(furfuryl alcohol) matrix, resulting in a stable, high effective permittivity, low and stable loss dielectric. Effective medium approximations were used to compare this with similar nanocomposite systems. The use of synthesized BTO nanocrystal photocatalysts …
Method And Apparatus For Fabricating Ceramic And Metal Components Via Additive Manufacturing With Uniform Layered Radiation Drying,
2019
Missouri University of Science and Technology
Method And Apparatus For Fabricating Ceramic And Metal Components Via Additive Manufacturing With Uniform Layered Radiation Drying, Ming-Chuan Leu, Amir Ghazanfari, Wenbin Li, Greg Hilmas, Robert G. Landers
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A freeform extrusion fabrication process for producing three - dimensional ceramic, metal and functionally gradient composite objects, including the steps of filling a plurality of paste sources with a respective plurality of aqueous paste compositions, operationally connecting respective syringes containing respective aqueous paste compositions to a mix ing chamber, moving a first aqueous paste composition from a first respective paste source into the mixing chamber, moving a second aqueous paste composition from a second respective paste source into the mixing chamber, mixing the first and second aqueous paste compositions to define a first admixture having a first admixture composition, extruding …
Off Axis Compressive Response Of Ice-Templated Ceramics,
2019
Old Dominion University
Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu
Mechanical & Aerospace Engineering Theses & Dissertations
The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading. …
Characterization Of Mgal₂O₄ Sintered Ceramics,
2019
Missouri University of Science and Technology
Characterization Of Mgal₂O₄ Sintered Ceramics, Nina Obradovic, William Fahrenholtz, Suzana Filipovic, Cole Corlett, Pavle Dordevic, Jelena Rogan, Predrag J. Vulic, Vladimir Buljak, Vladimir Pavlovic
Materials Science and Engineering Faculty Research & Creative Works
Single phase MgAl2O4 was made from a one-to-one molar ratio of MgO and Al2O3 powders mixed using ball-milling. Mixtures of MgO and Al2O3 were subsequently treated in planetary ball mill for 30, 60, 90 and 120 minutes in air. The aim of this study was to examine phase composition, microstructure, and densification behavior of sintered specimens. After sintering in dilatometer at 1500 °C, the powder was converted to single phase MgAl2O4. The results show that mechanical activation improved the densification behavior of MgAl2O4 sintered …
Biodegradable Composite Scaffold For Repairing Defects In Load-Bearing Bones,
2019
Missouri University of Science and Technology
Biodegradable Composite Scaffold For Repairing Defects In Load-Bearing Bones, D. E. Day, Ali Mohammadkhah
Materials Science and Engineering Faculty Research & Creative Works
A tissue scaffold for repair and regeneration of bone hard tissue or muscle, skin, or organ soft tissue, including load-bearing bone tissue, the scaffold comprising a core of biocompatible, biodegradable inorganic glass fibers; and a biocompatible, biodegradable, flexible polymer film surrounding the core and adhered to the core.
Ballistic Evaluation Of Carbon Nanotube Sheet Material In Multifunctional Applications,
2019
Air Force Institute of Technology
Ballistic Evaluation Of Carbon Nanotube Sheet Material In Multifunctional Applications, Casey M. Keilbarth
Theses and Dissertations
Significant development of carbon nanotubes has occurred since they were first studied in the 1990's. Attempts to capture the phenomenal molecular properties in practical applications are gaining ground as new methods of producing CNTs have been developed. This thesis sought to determine if the addition of commercially produced CNT sheets to thin carbon fiber panels improved the ballistic properties of the panel. The difference between 0 and 4 CNT sheets was studied. The hypothesis was that inte- grating CNT sheets into the laminate would increase the projectile energy absorbed by the panel and reduce the damage to the panel incurred …
Interlaminar Shear Performance Of High Temperature Composites,
2019
Air Force Institute of Technology
Interlaminar Shear Performance Of High Temperature Composites, Tyler A. Wallis
Theses and Dissertations
Interlaminar shear properties of a high temperature polymer matrix composite (HTPMC) and a ceramic matrix composite (CMC) were evaluated at elevated tempera- ture. Two variants of the HTPMC were studied. Both consisted of a high-temperature polyimide (AFR-PE-4) matrix reinforced with Astroquartz-III pre-impregnated glass fabric woven in an eight-harness-satin weave. The first HTPMC variant also contained stainless steel foil at the midplane, while the second HTPMC variant did not. The interlaminar shear strength (ILSS) of both variants of the HTPMC was evaluated at 204°C in laboratory air. The addition of the stainless steel foil resulted in significant loss of ILSS for …
Creep Of Nextel 720/Alumina Ceramic Matrix Composite With Diamond-Drilled Effusion Holes At 1200°C In Air And In Steam,
2019
Air Force Institute of Technology
Creep Of Nextel 720/Alumina Ceramic Matrix Composite With Diamond-Drilled Effusion Holes At 1200°C In Air And In Steam, Megan L. Harkins
Theses and Dissertations
A recent study evaluated tensile stress-strain and tensile creep behavior of an oxide-oxide composite (Nextel™720/alumina) with laser-drilled effusion holes at 1200°C. It was determined that the presence of laser-drilled holes degraded the mechanical properties and performance of the CMC as a result of damage caused to the composite microstructure by the laser drilling process. Based on these results, the present effort sought to assess the effects of diamond-drilled holes on the mechanical behavior of this CMC. Tensile properties of the N720/A composite at 1200°C in laboratory air were unaffected by the presence of an array of 17 diamond-drilled effusion holes. …
Investigation Of Transition-Metal Ions In The Nickel-Rich Layered Positive Electrode Materials For Lithium-Ion Batteries,
2019
University of Kentucky
Investigation Of Transition-Metal Ions In The Nickel-Rich Layered Positive Electrode Materials For Lithium-Ion Batteries, Shuang Gao
Theses and Dissertations--Chemical and Materials Engineering
Layered lithium transition-metal oxides (LMOs) are used as the positive electrode material in rechargeable lithium-ion batteries. Because transition metals undergo redox reactions when lithium ions intercalate in and disintercalate from the lattice, the selection and composition of transition metals largely influence the electrochemical performance of LMOs. Recently, a Ni-rich compound, LiNi0.8Co0.1Mn0.1O2 (NCM811), has drawn much attention. It is expected to replace its state-of-the-art cousins, LiCoO2 (LCO) and LiNi1/3Co1/3Mn1/3O2 (NCM111), because of its higher capacity, lower cost, and reduced toxicity. However, the excess Ni, as a …
Experimental And Numerical Simulation Of Split Hopkinson Pressure Bar Test On Borosilicate Glass,
2019
Michigan Technological University
Experimental And Numerical Simulation Of Split Hopkinson Pressure Bar Test On Borosilicate Glass, Mayank K. Bagaria
Dissertations, Master's Theses and Master's Reports
This study is an extension to the design of ceramic materials component exposed to bullet impact. Owing to the brittle nature of ceramics upon bullet impact, shattered pieces behave as pellets flying with different velocities and directions, damaging surrounding components. Testing to study the behavior of ceramics under ballistic impact can be cumbersome and expensive. Modeling the set-up through Finite Element Analysis (FEA) makes it economical and easy to optimize. However, appropriately incorporating the material in modeling makes laboratory testing essential. Previous efforts have concentrated on simulating crack pattern developed during 0.22 caliber pellet impact on Borosilicate glass. A major …
Form Stable Phase-Change Materials,
2019
University of Akron
Form Stable Phase-Change Materials, Russell Dent, Marjan Kashfipour, Nitin Mehra, Jiahua Zhu
Williams Honors College, Honors Research Projects
This work investigates the use of two different polyols, xylitol (Xyl) and erythritol (Ery), in conjunction with boron nitride (BN) aerogels, for the purpose of creating thermally conductive composites. While the BN filler in Xyl composites achieved a high anisotropic thermal conductivity of up to 4.53 W/m-K at 18.2 weight percent filler loading, they do not exhibit good phase-change material qualities due to a low solidification enthalpy even at low cooling rates. Alternatively, the BN-Ery composites have shown promising results with a solidification enthalpy of 225.14 J/g and a melting enthalpy of 385.84 J/g at a heat rate of 5 …
