Thermoelectric Half-Heuslers: Synthesis, Processing, And Performance, 2016 Boise State University
Thermoelectric Half-Heuslers: Synthesis, Processing, And Performance, Joseph Robert Croteau
Boise State University Theses and Dissertations
Thermoelectric half-Heusler compounds have potential to convert the heat wasted from industrial and transportation processes to useful electricity. Among the highest performing half-Heusler compounds are nano-structured bulk materials which have been arc-melted, pulverized into a nano-powder, and sintered by DC-hot press. High performing n- and p-type half-Heusler compounds with nominal composition of Hf0.25Zr0.75NiSn0.99Sb0.01 and Nb0.75Ti0.25FeSb, respectively, have been provided to us in both dense and powder form by our collaborators at the University of Houston. We consolidate these powders by SPS, refine these ...
Formation Cadmium And Densification Of Manganese Ferrite, 2016 Missouri University of Science and Technology
Formation Cadmium And Densification Of Manganese Ferrite, B. W. Jong, P. D. Ownby
P. Darrell Ownby (Emeritus)
Formation of Ni-ferrite, Mn-ferrite, NiZn-ferrite, Zn-ferrite and Mg-ferrite have been investigated using X-ray diffraction analysis. Jander's diffusion equation described the data from these investigations over a portion of the temperature ranges studied. However, the reaction mechanisms and sequences involved in the formation of mixed ferrites have not been well defined in the literature. The purposes of this investigation were: ( 1) To further the understanding of the formation of CdMnferrite by studying first the kinetics of the formation of Cd-ferrite and Cd-manganite, which provides a basis for understanding the details of the mixed CdMn-ferrite reaction and to obtain the optimum ...
A Preliminary Study Of The Effect Of Heat Treatment On The Strength And Microstructure Of A Glass-Ceramic Material, 2016 Missouri University of Science and Technology
A Preliminary Study Of The Effect Of Heat Treatment On The Strength And Microstructure Of A Glass-Ceramic Material, P. D. Ownby
P. Darrell Ownby (Emeritus)
"The strength and microstructure of a glass-ceramic material of the composition 53 percent SiO₂, 19 percent Al₂O₃, 15 percent MgO, and 13 percent Li₂O were studied. Cylindrical specimens of glass were formed and heat-treated to six different temperature levels for various time periods. The method of strength testing used was a diametral compression loading technique. It was found that the strength of this material increased initially with heat-treatment but then decreased. The strength characteristics of the completely crystallized glass ceramic material were found to be dependent on the initial nucleation period. Some factors which influenced anomalous crystal growth are described ...
Feasibility Of Fused Deposition Of Ceramics With Zirconia And Acrylic Binder, 2016 California Polytechnic State University, San Luis Obispo
Feasibility Of Fused Deposition Of Ceramics With Zirconia And Acrylic Binder, Lindsay V. Page
Master's Theses and Project Reports
Processing of ceramics has always been difficult due to how hard and brittle the material is. Fused Deposition of Ceramics (FDC) is a method of additive manufacturing which allows ceramic parts to be built layer by layer, abetting more complex geometries and avoiding the potential to fracture seen with processes such as grinding and milling. In the process of FDC, a polymeric binder system is mixed with ceramic powder for the printing of the part and then burned out to leave a fully ceramic part. This experiment investigates a new combination of materials, zirconia and acrylic binder, optimizing the process ...
Design And Testing Of A Top Mask Projection Ceramic Stereolithography System For Ceramic Part Manufacturing, 2016 California Polytechnic State University, San Luis Obispo
Design And Testing Of A Top Mask Projection Ceramic Stereolithography System For Ceramic Part Manufacturing, Dylan Robert De Caussin
Master's Theses and Project Reports
Ceramic manufacturing is an expensive process with long lead times between
the initial design and final manufactured part. This limits the use of ceramic as a viable material unless there is a large project budget or high production volume associated with the part. Ceramic stereolithography is an alternative to producing low cost parts through the mixing of a photo curable resin and ceramic particles. This is an additive manufacturing process in which each layer is built upon the previous to produce a green body that can be sintered for a fully dense ceramic part.
This thesis introduces a new approach ...
Devitrification Rates Of Fused Silica In The Presence Of Trace Impurities, 2016 University of Tennessee, Knoxville
Devitrification Rates Of Fused Silica In The Presence Of Trace Impurities, Nicholas Kivi, Adrian Moore, Kayla Dyar, Samuel Haaf
University of Tennessee Honors Thesis Projects
No abstract provided.
Magnetron Sputtering And Corrosion Of Ti-Al-C And Cr-Al-C Coatings For Zr-Alloy Nuclear Fuel Cladding, 2016 University of Tennessee - Knoxville
Magnetron Sputtering And Corrosion Of Ti-Al-C And Cr-Al-C Coatings For Zr-Alloy Nuclear Fuel Cladding, Devin Alan Roberts
The disaster at the Fukushima Daiichi Nuclear Power Plant in March 2011 bought renewed focus to the issue of corrosion in nuclear fuel cladding applications. This thesis reports on the background behind these issues, the investigation strategy, and the analysis of experiments focused on mitigating oxidation of Zr-alloy fuel cladding. This thesis seeks to develop magnetron sputtered Ti-Al-C and Cr-Al-C coatings for Zr-alloy substrates and characterize the as-deposited and corroded samples.
Ti-Al-C and Cr-Al-C coatings were deposited onto ZIRLO, Si, and Al2O3 [Aluminum Oxide] substrates under various sputtering conditions. A combinatorial sputtering method was employed to refine ...
Power Maximization For Pyroelectric, Piezoelectric, And Hybrid Energy Harvesting, 2016 Virginia Commonwealth University
Power Maximization For Pyroelectric, Piezoelectric, And Hybrid Energy Harvesting, Murtadha A. Shaheen
Theses and Dissertations
The goal of this dissertation consists of improving the efficiency of energy harvesting using pyroelectric and piezoelectric materials in a system by the proper characterization of electrical parameters, widening frequency, and coupling of both effects with the appropriate parameters.
A new simple stand-alone method of characterizing the impedance of a pyroelectric cell has been demonstrated. This method utilizes a Pyroelectric single pole low pass filter technique, PSLPF. Utilizing the properties of a PSLPF, where a known input voltage is applied and capacitance Cp and resistance Rp can be calculated at a frequency of 1 mHz to 1 Hz ...
Ion Irradiation-Induced Microstructural Change In Sic, 2015 University of Tennessee - Knoxville
Ion Irradiation-Induced Microstructural Change In Sic, Chien-Hung Chen
The high temperature radiation resistance of nuclear materials has become a key issue in developing future nuclear reactors. Because of its mechanical stability under high-energy neutron irradiation and high temperature, silicon carbide (SiC) has great potential as a structural material in advanced nuclear energy systems.
A newly developed nano-engineered (NE) 3C SiC with a nano-layered stacking fault (SFs) structure has been recently considered as a prospective choice due to enhanced point defect annihilation between layer-type structures, leading to outstanding radiation durability.
The objective of this project was to advance the understanding of gas bubble formation mechanisms under irradiation conditions in ...
Ion Irradiation Characterization Studies Of Max Phase Ceramics, 2015 University of Tennessee - Knoxville
Ion Irradiation Characterization Studies Of Max Phase Ceramics, Daniel William Clark
The family of layered carbides and nitrides known as MAX phase ceramics combine many attractive properties of both ceramics and metals due to their nanolaminate crystal structure and are promising potential candidates for application in future nuclear reactors. This thesis reports on the background, design, and analysis of an experiment focused on determining the effects of energetic heavy ion irradiations on polycrystalline samples of titanium silicon carbide 312, titanium aluminum carbide 312, and titanium aluminum carbide 211. The irradiation conditions consisted of ion doses between 10 and 30 displacements per atom at temperatures of 400 and 700 degrees Celsius, conditions ...
Cobalt Ferrite Nanoparticles Fabricated Via Co-Precipitation In Air: Overview Of Size Control And Magnetic Properties, 2015 Florida International University
Cobalt Ferrite Nanoparticles Fabricated Via Co-Precipitation In Air: Overview Of Size Control And Magnetic Properties, Dennis Toledo
FIU Electronic Theses and Dissertations
Cobalt Ferrite has important, size-dependent magnetic properties. Consequently, an overview of particle size is important. Co-precipitation in air was the fabrication method used because it is comparatively simple and safe. The effects of three different reaction times including 1, 2, 3 hour(s) on particle size were compared. Also, the effectiveness of three different capping agents (Oleic Acid, Polyvinylpyrollidone (PVP), and Trisodium Citrate) in reducing aggregation and correspondingly particle size were examined. Using Welch’s analysis of variance (ANOVA) and the relevant post hoc tests, there was no significant difference (p=0.05) between reaction times of 1 hour and ...
Grain Boundary Migration Of Nio-Mgo Alloys, 2015 Purdue University
Grain Boundary Migration Of Nio-Mgo Alloys, Xin Li Phuah, David Lowing, John Blendell
The Summer Undergraduate Research Fellowship (SURF) Symposium
Grain boundary engineering offers enhanced control of microstructure development during processing, leading to improved final material properties. However, using the effects of the interfacial energy anisotropy on grain boundary mobility to control microstructure development is not well understood. The NiO-MgO system is studied as it has complete solid solubility and a transition in the faceting behavior with composition due to changes in the interfacial energy anisotropy. NiO-MgO powders were produced through the amorphous citrate process and modifications to the process were made to reduce particle and agglomerate size. The powders were pressed and sintered in various conditions to produce fine ...
Ion Irradiation Induced Damage And Dynamic Recovery In Single Crystal Silicon Carbide And Strontium Titanate, 2015 University of Tennessee - Knoxville
Ion Irradiation Induced Damage And Dynamic Recovery In Single Crystal Silicon Carbide And Strontium Titanate, Haizhou Xue
The objective of this thesis work is to gain better understanding of ion-solid interaction in the energy regime where electronic and nuclear energy loss are comparable. Such responses of materials to ion irradiations are of fundamental importance for micro-electronics and nuclear applications. The ion irradiation induced modification for the crystal structure, the physical and chemical properties etc. may strongly affect the performance of functional materials that needs to be better understood.
Experimentally, ion irradiation induced damage accumulation and dynamic recovery in SiC [silicon carbide] and SrTiO3 [strontium titanate] were studied in this dissertation project. Five chapters are presented: Firstly ...
Crystal Growth And Physical Property Characterization Of Complex Perovskite Oxides, 2015 University of Tennessee - Knoxville
Crystal Growth And Physical Property Characterization Of Complex Perovskite Oxides, Ling Li
Bulk EuTiO3 [europium titanate], a quantum paraelectric antiferromagnet, is shown to exhibit multiferroic behavior in strained thin film form, which highlights the spin-phonon coupling in this system. We have investigated the structural, elastic, magnetic, thermal and transport properties of single crystals of EuTiO3 as well as doped system EuTi1-xBxO3 (B = Zr, Nb) [Zr and Nb doped europium titanate] utilizing various experimental techniques and theoretical calculations.
The cubic to tetragonal structural transition in pure EuTiO3 is characterized by a pronounced step-like softening of the elastic moduli near 288 K [kelvin], which resembles that ...
Development And Improvement Of Cerium Activated Gadolinium Gallium Aluminum Garnets Scintillators For Radiation Detectors By Codoping, 2015 University of Tennessee - Knoxville
Development And Improvement Of Cerium Activated Gadolinium Gallium Aluminum Garnets Scintillators For Radiation Detectors By Codoping, Fang Meng
Ce doped Gd3Ga3Al2O12 [gadolinium gallium aluminium oxides] is considered as a promising candidate for the next generation Positron Emission Tomography material due to its high light yield in theory. This dissertation is focused on studying the Gd3Ga3Al2O12:Ce crystals by codoping, aiming to improve the light yield and decay time experimentally and understand the underlying mechanism.
The work starts from prescreening appropriate codopants for Gd3Ga3Al2O12:Ce crystals. A cost-effective method is developed to predict the performance of the single crystals by characterizing the radioluminescence intensity and photoluminescence decay of the small polycrystalline pellets. This method is demonstrated by showing that ...
Disorder In Mg1-Xnixal2o4 Spinel And Its Impact On The Response To Swift Heavy Ion Irradiation, 2015 University of Tennessee - Knoxville
Disorder In Mg1-Xnixal2o4 Spinel And Its Impact On The Response To Swift Heavy Ion Irradiation, Brandon Alexander Perlov
Spinels, which are currently used in optical applications, have many proposed functions in the nuclear industry, such as a nuclear waste form due to its radiation resistance. Disordering plays a key role in the response of spinel to a wide range of irradiation conditions. The first part of this research project was on characterizing the type and degree of disorder that can be induced by chemical substitution in the magnesium nickel aluminate spinel solid solution series (Mg(1-x)Ni(x)Al2O4). Neutron total scattering has been used to characterize the structure at both the cation and anion sublattices. High-resolution pair ...
Computational And Experimental Studies Of Ca12al14o33, Mayenite, 2015 University of Tennessee - Knoxville
Computational And Experimental Studies Of Ca12al14o33, Mayenite, Elijah Duncan Barlow
In this study C₁₂Al₁₄O₃₃ [mayenite] is computationally modeled, synthesized, and compared to literature in order to build a knowledge base for the further study of this compound. It is hoped that this study of mayenite will lead to the development of a new transparent conductive oxide that uses earth abundant elements instead of rare earth elements. For this study polycrystalline mayenite was synthesized using traditional solid-state synthesis techniques, and growth of a single crystal was then attempted. The VASP software package was then used to simulate the compound, both physically and electronically. The results of the simulation were then compared ...
Electronic Energy Loss Of Heavy Ions And Its Effects In Ceramics, 2015 University of Tennessee - Knoxville
Electronic Energy Loss Of Heavy Ions And Its Effects In Ceramics, Ke Jin
Energy loss of medium energy heavy ions (i.e. Cl, Br, I, and Au) in thin compound foils containing light elements (i.e. silicon carbide and silicon dioxide) is directly measured using a time-of-flight elastic recoil detection analysis (ToF-ERDA) technique. An improved data analysis procedure is proposed to provide the experimentally determined electronic stopping powers. This analysis procedure requires reliable predictions of nuclear stopping. Thus, the nuclear stopping predicted by the Stopping and Range of Ions in Matter (SRIM) code is validated by measuring the angular distribution of 1 MeV Au ions after penetrating a thin silicon nitride foil, using ...
Impact Of Fuel Rod Coatings On Reactor Performance And Safety, 2015 University of Tennessee - Knoxville
Impact Of Fuel Rod Coatings On Reactor Performance And Safety, Ian Robert Stewart
This study evaluates the use of a ceramic coating on the Zr-alloy cladding within a PWR using four ceramic compounds of 5 and 10 micron thicknesses: ZrO2, TiAlN, Ti2AlC, and Ti3AlC2. The film’s impact is assessed for variation on: reactivity, fuel cycle length, maximum temperature, film’s roughness, and transient conditions. The reactivity is analyzed using the following methods: change in the multiplication factor (k) each film introduces to the system using the ABH method, and Monte Carlo software (MCNP). Both methods are in good agreement, yielding less than half a percent change from a reference, no-film fuel pin ...
Reaction Kinetics Of Rare Earth And Actinide Materials, 2015 Boise State University
Reaction Kinetics Of Rare Earth And Actinide Materials, Brian Jon Jaques
Boise State University Theses and Dissertations
This dissertation presents the effects of atmosphere, time, and energy input (thermal and mechanical) on the kinetics of gas-solid and solid-solid reactions in systems of dysprosium, uranium, oxygen, and nitrogen. Accordingly, Chapter Two presents a novel synthesis technique used to form DyN via a gas-solid reaction between dysprosium and nitrogen. DyN was rapidly formed through a mechanochemical process in a high energy ball mill at ambient temperatures. The progress of the reaction was quantified using in situ temperature and pressure measurements coupled with microscopy and x-ray diffraction. It was found that the rate of the nitridation reaction is controlled by ...