Mechanical Failure Of Metal/Ceramic Interfacial Regions Under Shear And Tensile Loading,
2021
Louisiana State University
Mechanical Failure Of Metal/Ceramic Interfacial Regions Under Shear And Tensile Loading, Xiaoman Zhang
LSU Doctoral Dissertations
Quantitative assessment of the adhesion strength of ceramic hard coatings on substrates is a subject of great technological importance as well as current scientific relevance. Achievement of reliable and quantitative measurements of interfacial strength has proven difficult over the past two decades. In this dissertation, how the deformation and fracture behavior of ceramic/metal/substrate interfacial regions under shear and tensile loading is influenced by the structure and chemical composition of the interfacial region were observed and discussed. Interfacial shear failure experiments were carried out on focused ion beam fabricated micro pillars containing interfacial regions of ceramic/metal/substrate systems. Detailed characterization was carried …
Cyclic Regeneration Of Nanostructured Composites For Catalytic Applications,
2021
Missouri University of Science and Technology
Cyclic Regeneration Of Nanostructured Composites For Catalytic Applications, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
A cermet catalyst material, defining a matrix having interconnected open pores, the matrix selected from the group consisting of YSZ and CGO and defining a substrate, a ceramic coating having a general formula AyBnOx at least partially coating the pores, and a plurality of metal particles A at least partially embedded in the ceramic coating. A is selected from the group consisting of Co, Cu, Ce, Ni, Ti, and combinations thereof and B is selected from the group consisting of Mo, W, Ce, and combinations thereof. When the coating is in a first oxidizing atmosphere and at a temperature between …
Experimental Investigation Of Surface Resistivity Of Yttrium Stabilized Zirconium As A Thin Film,
2021
Seton Hall University
Experimental Investigation Of Surface Resistivity Of Yttrium Stabilized Zirconium As A Thin Film, Matthew J. Melfi
Seton Hall University Dissertations and Theses (ETDs)
Solid Oxide Fuel Cells are devices that use electrochemical reactions to convert chemical energy from fuel to electricity. In comparison with coal power plants, a Solid Oxide Fuel Cell, produces a higher electrical conversion efficiency. However, at higher temperatures (1000°C) it creates a lower ionic conductivity, which limit the Solid Oxide Fuel Cells. When lowering the temperature, the ohmic resistance increases. In our research, an Yttrium Stabilized Zirconium layer will be produced from a fine dimple grain structure allowing high flow of oxygen mobility. This mobility increases ionic conductivity and decrease ohmic loss. The goal of our research is first …
Design And Fabrication Of A Microstrip Bandpass Filter In Ltcc,
2021
University of Arkansas, Fayetteville
Design And Fabrication Of A Microstrip Bandpass Filter In Ltcc, Allison Rucker
Electrical Engineering Undergraduate Honors Theses
The goal of the project was to design and fabricate a bandpass filter with a center frequency of 25GHz with a 2GHz bandwidth. The first step was to do the calculation to design a bandpass filter to meet these specifications along with the properties of the DupontTM GreenTapeTM 9K7. HFSS was then used to verify the results from the initial calculations. There was a significant error between the two results, so more tweaking was done to the calculations to get a better center frequency. After a final design was decided, the fabrication process started. Low-Temperature Co-Fired Ceramics (LLTC) …
Study Of Static And Dynamical Properties Of Complex Antiferroelectrics Materials,
2021
University of Arkansas, Fayetteville
Study Of Static And Dynamical Properties Of Complex Antiferroelectrics Materials, Kinnary Yogeshbhai Patel
Graduate Theses and Dissertations
The aim of this dissertation is the investigation of the static and dynamical properties of the complex antiferroelectric materials using Effective Hamiltonian method and First principles calculations. In chapter 3, a novel elemental interatomic coupling in perovskite materials which bilinearly couples the antiferroelectric displacements of cations with the rotations of the oxygen octahedra. This new coupling explains a very complex crystal structure of prototypical antiferroelectric PbZrO3. My explanation provides a unified description of many other complex antipolar crystal structures in variety of perovskite materials, including the occurrence of incommensurate phases in some of them. In chapter 4, results and analysis …
Solid State Synthesis And Characterization Of Apatite Based Ceramic Waste Form For The Immobilization Of Radioactive Iodine,
2021
Louisiana State University and Agricultural and Mechanical College
Solid State Synthesis And Characterization Of Apatite Based Ceramic Waste Form For The Immobilization Of Radioactive Iodine, Md Imdadul Islam
LSU Doctoral Dissertations
The growing demand for nuclear power in the United States and worldwide is accountable for addressing the major concern of radioactive waste, involving the technical challenges of maintaining the nuclear fuel cycle and immobilizing high-level wastes for safe disposal in geological storage. The appropriate selection of waste forms for spent nuclear fuel such as fission products and radionuclides can be effective means for a feasible and sustainable nuclear fuel cycle. But highly volatile radionuclides such as iodine (129) are of specific concern due to its extraordinary long half-life (15.7 million years). Due to its poor solubility and high volatility at …
Fatigue Of Two Oxide/Oxide Ceramic Matrix Composites At 1200°C In Air And In Steam. Effect Of Diamond Drilled Effusion Holes,
2021
Air Force Institute of Technology
Fatigue Of Two Oxide/Oxide Ceramic Matrix Composites At 1200°C In Air And In Steam. Effect Of Diamond Drilled Effusion Holes, Anthony R. Cabri
Theses and Dissertations
The tension-tension fatigue behavior of two oxide-oxide ceramic matrix composites (CMCs) was investigated at 1200°C in laboratory air and steam. Both composites consist of a porous oxide matrix reinforced with laminated, woven mullite/alumina (NextelTM720) fibers. The first composite had an alumina matrix, while the second had an alumina-mullite matrix. First, we assessed the effects of incorporating mullite into the matrix material on fatigue performance by studying the tension-tension fatigue behavior of alumina-mullite matrix CMC. Second, we evaluated the effects of effusion holes on the alumina matrix CMC's fatigue performance. Specimens containing an array of 17 effusion holes of 0.5-mm diameter …
Static Fatigue Of Hi-Nicalon™ S Ceramic Fiber Tows At 600°C In Air And Silicic Acid-Saturated Steam,
2021
Air Force Institute of Technology
Static Fatigue Of Hi-Nicalon™ S Ceramic Fiber Tows At 600°C In Air And Silicic Acid-Saturated Steam, Caleigh M. Nelson
Theses and Dissertations
Ceramic matrix composites (CMCs) have the potential to be utilized in applications such as hypersonic vehicles, aircraft leading edges, hot sections of engines, and rocket nozzles. Of particular interest are advanced SiC/SiC composites that can withstand the elevated temperatures and harsh oxidizing environments while maintaining their properties and structural integrity under an applied load. Steam, a major component of combustion environment, is one such aggressive oxidizing environment. As steam passes through the SiC/SiC composite, entering the composite interior through the cracks in the SiC matrix, it becomes saturated with silicic acid, Si(OH)4. Before incorporating SiC/SiC composites in the …
Research Trend Of Metal Matrix Composites Reinforced With Silica Extracted By Green Route: A Bibliometric Analysis,
2021
Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University) (SIU), Lavale, Pune, India
Research Trend Of Metal Matrix Composites Reinforced With Silica Extracted By Green Route: A Bibliometric Analysis, Rinku Datkhile, Meena Laad, Babaji Ghule
Library Philosophy and Practice (e-journal)
Metal Matrix Composites have acquired an important place in the engineering applications due to their distinctive characteristics such as high specific strength, lower specific gravity, improved material stiffness, better durability, enhanced creep and fatigue strength etc. Worldwide scientists are working on the improvement of mechanical properties of composite materials. The present work attempts to summarise all the research carried out on metal matrix composites reinforced with silica extracted by green route and provides up-to-date research material for researchers who are interested in the field of composites with metal matrices. Scopus databases and software such as Gephi Vos Viewer and Table2Net …
Automated Control System For The Remote-Controlled Torch Positioner,
2021
The University of Akron
Automated Control System For The Remote-Controlled Torch Positioner, Christopher Ferguson, Anna Abate, Kyle Cramer, Alex Sabitsch, Jacob Stefanko
Williams Honors College, Honors Research Projects
The goal of this project is to design and implement a controls system for Dr. Morscher’s burner rig. The rig serves to simulate jet turbine conditions and test how materials, specifically ceramic matrix composites, react under high temperatures and stresses. Currently, the location of the torch relies solely on manual adjustments and has no automated control system. The improved design will automatically adjust the torch position based on the desired temperature of the sample being tested, therefore maintaining a steady environment for the sample. The current method of manual adjustments for regulating temperature is a crude solution that does not …
A Kinetic Evaluation For Phenothiazine Base Copolymers,
2021
Missouri University of Science and Technology
A Kinetic Evaluation For Phenothiazine Base Copolymers, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
In here, the non-isothermal decomposition kinetics of co-polymers-based phenothiazine was present-ed. For this, firstly, 3, 7-di-2-thienyl-10H-phenothiazine (TF) was prepared via an optimized Suzu-ki–Miyaura cross-coupling reaction. After monomer (TF) characterization, the copolymerization re-actions with EDOT and thiophene were performed by the electrochemical technique. The molecular masses of the co-polymers were found by gel permeation chromatography (GPC) analysis. Thermal characterizations of the resulting polymers were conducted by thermogravimetric analyses. The thermal decomposition kinetics of the resulting polymers was also performed. For this, the kinetic methods (Tang, FWO, KAS, Kissinger, and Friedman) based on the multiple heating rates were used. Several kinetic parameters …
Contributions To The Performance Of Thin Film Capacitors For High Reliability Applications,
2021
Missouri University of Science and Technology
Contributions To The Performance Of Thin Film Capacitors For High Reliability Applications, Daniel Krueger
Doctoral Dissertations
"Capacitors are critical devices in microelectronic assemblies that must be incorporated into electronic systems through a variety of ways such as integrated or discrete devices. This work has developed new thin film capacitors deposited directly onto multichip module or printed circuit board surfaces to benefit from closer integration that enhances system performance for use in high reliability applications. The capacitors serve as filters or provide tuning and energy storage functions. Unexpected performance was observed during development that included low adhesion of the films to the substrates, higher effective dielectric constants than reported in literature, and low yields. Three publications resulted …
Thermal And Mechanical Properties Of Novel Carbide Materials,
2021
Missouri University of Science and Technology
Thermal And Mechanical Properties Of Novel Carbide Materials, Evan Charles Schwind
Doctoral Dissertations
"This research focuses on studying the thermal and mechanical properties of novel carbide materials at room and elevated temperatures. The novel carbide materials investigated include zeta phase tantalum carbide (ζ-Ta4C3-x) and a high entropy (Ta,Hf,Nb,Zr)C carbide. The electrical resistivity and thermal conductivity of zeta phase tantalum carbide (~96 wt.%) were measured as 160 ± 4.2 μΩ-cm and 9.6 W/m•K. These are higher and lower (respectively) than for cubic tantalum carbide, most likely due to planes of carbon vacancies present in the ζ-Ta4C3-x crystal structure. The thermal conductivity of (Ta,Hf,Nb,Zr)C was lower than any …
Degradation Issues And Stabilization Strategies Of Protonic Ceramic Electrolysis Cells For Steam Electrolysis,
2021
Michigan Technological University
Degradation Issues And Stabilization Strategies Of Protonic Ceramic Electrolysis Cells For Steam Electrolysis, Hanrui Su, Yun Hang Hu
Michigan Tech Publications, Part 1
Protonic ceramic electrolysis cells (PCECs) are attractive electrochemical devices for converting electrical energy to chemicals due to their high conversion efficiency, favorable thermodynamics, fast kinetics, and inexpensive materials. Compared with conventional oxygen ion-conducting solid oxide electrolysis cells, PCECs operate at a lower operating temperature and a favorable operation mode, thus expecting high durability. However, the degradation of PCECs is still significant, hampering their development. In this review, the typical degradations of PCECs are summarized, with emphasis on the chemical stability of the electrolytes and the air electrode materials. Moreover, the degradation mechanism and influencing factors are assessed deeply. Finally, the …
Metal Supported Solid Oxide Fuel Cell Using Proton Conducting Electrolyte For Direct Ammonia Utilization,
2021
West Virginia University
Metal Supported Solid Oxide Fuel Cell Using Proton Conducting Electrolyte For Direct Ammonia Utilization, Edwin Vega Hiraldo
Graduate Theses, Dissertations, and Problem Reports (ETD)
Transportation represents about 27% of global warming greenhouse gas emissions nowadays. To reduce these emissions, fuel cell electric vehicles have been poised to be a new trend to provide zero-emission transportation. Among them, solid oxide fuel cells (SOFCs) offer efficient, clean energy, especially when powered by carbon-free fuel, such as ammonia. To enable onboard ammonia-fed SOFCs, a metal-supported, proton-conducting SOFC is investigated in this study. The metal support would provide physical robustness for thermal shock during vehicles’ quick start-up and shutdown, reduce internal temperature gradients due to the greater thermal conductivity of the metal, and enable conventional metal joining for …
Reclamation Of Fused Silica From Investment Shells Used For Casting Steel,
2021
Georgia Southern University
Reclamation Of Fused Silica From Investment Shells Used For Casting Steel, Samuel L. Holt
College of Graduate Studies: Theses & Dissertations
Fused silica is widely used for investment casting shell molds. Fused silica shells are discarded after being used for casting one time. This is due to the transformation of fused silica to beta cristobalite above 1652℉ (900℃). To reduce cost and waste of investment casting foundries, this study is exploring a method to inhibit transformation of fused silica and reclaim it from high temperature investment casting shells. This research has employed firing to minimalize fused silica transformation to cristobalite. The phase transformation is minimalized due to sintering and coarsening of the particles during firing. Coarsening reduces surface area to volume …
Improving Performance And Durability Of Intermediate Temperature Proton‐Conducting Solid Oxide Electrolysis Cells Via Materials Design And Catalyst Surface Engineering,
2021
West Virginia University
Improving Performance And Durability Of Intermediate Temperature Proton‐Conducting Solid Oxide Electrolysis Cells Via Materials Design And Catalyst Surface Engineering, Hanchen Tian
Graduate Theses, Dissertations, and Problem Reports (ETD)
Solid oxide steam electrolysis cell, a promising electrical-chemical conversion device for the next generation efficient hydrogen production and energy storage, has been actively studied because of their high energy conversion efficiencies and prospective applications as electrochemical reactors. After decades of research on protonic ceramic materials, remarkable advances have been made in the protonic ceramic electrochemical cells (PCECs) air electrode and electrolyte. However, the existing air electrodes are far from satisfying the requirements of practical applications, a series of issues, including the lack of active and durable electrodes, greatly limit the commercialization. To date, the systematic development of triple conducting catalysts …
Increasing The Seebeck Coefficient Of Thermoelectric Calcium Cobaltite Ceramics Through Incorporation Of Rare-Earth Elements,
2021
West Virginia University
Increasing The Seebeck Coefficient Of Thermoelectric Calcium Cobaltite Ceramics Through Incorporation Of Rare-Earth Elements, Andre Fabian Fernandes
Graduate Theses, Dissertations, and Problem Reports (ETD)
The demand for alternative sources of energy continues to grow, so it is essential to look for alternatives that are environmentally sustainable to minimize the environmental impact of energy generation. Projections suggest that renewables have the potential to make up over fifty percent of power generation by 2035. Studies have shown that in 2020 more than 62% of the energy produced in the US was lost, with most of this energy being in the form of waste heat. Waste heat can be utilized to improve the efficiency of power production or even power other devices. This waste heat can be …
Effect Of Applied Pressure During Sintering On The Densification And Mechanical Properties Of Sicf/Sic Composites Prepared By Electrophoretic Infiltration,
2020
1. Nano Center Indonesia, Banten 15314, Indonesia 2. Department of Mechanical Engineering, Universitas Mercu Buana, Jakarta 11650, Indonesia
Effect Of Applied Pressure During Sintering On The Densification And Mechanical Properties Of Sicf/Sic Composites Prepared By Electrophoretic Infiltration, Alfian Noviyanto
Makara Journal of Science
SiC-fiber-reinforced SiC matrix ceramic (SiCf/SiC) composites were successfully fabricated by electrophoretic infiltration and sintering at various applied pressures. The effect of applied pressure (i.e., 5, 10, and 20 MPa) was thoroughly examined, and applied pressure appears to influence the densification and mechanical properties of SiCf/SiC composites. The densities of SiCf/SiC composites prepared at applied pressure of 5, 10, and 20 MPa were 2.99, 3.10, and 3.16 g/cm3, respectively. All samples showed dense microstructures in their matrix areas; however, many closed pores were found with increasing pressure. Pressure induced densification in the fiber …
Numerical Evaluation Of Effective Thermal Response Of Heterogeneous Materials,
2020
University of New Mexico
Numerical Evaluation Of Effective Thermal Response Of Heterogeneous Materials, Kevin W. Irick
Mechanical Engineering ETDs
Heterogeneity in materials leads to increased complication of physics, at the level or scale where heterogeneity exists, making analysis and material behavior predictions more difficult. As a result of the intricate descriptions or understanding of the physics required to determine the behavior of a heterogenous material or system, practitioners frequently prefer the use of effective properties or responses. This body of work is dedicated to performing computational analyses on the thermal behavior of heterogeneous materials and evaluating the corresponding analyses using formal verification approaches. Custom finite element method code was used for solving the heat equation in a variety of …
