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Articles 6871 - 6900 of 16774

Full-Text Articles in Engineering

Fundamental Insights On The Electrolysis Of Co2 Using Solid Oxide Electrolysis Cells, Juliana Silva Alves Carneiro Jan 2019

Fundamental Insights On The Electrolysis Of Co2 Using Solid Oxide Electrolysis Cells, Juliana Silva Alves Carneiro

Wayne State University Dissertations

The work reported in this thesis focused on providing a fundamental understanding, at the molecular level, required to guide the effective design of electrocatalysts towards a superior reaction kinetics on the electrode of solid oxide electrolysis cells SOECs devices (SOECs) during the CO2 electrolysis. High temperature SOECs are electrochemical energy conversion technologies, that have emerged as promising alternatives to mitigate environmental issues associated with combustion-based technologies, such as the rising atmospheric CO2 levels. The conversion of excess CO2 into high-energy molecules, such as CO can be efficiently achieved through the use of SOEC – which facilitates the electrochemical reduction of …


Primary Dendrite Trunk Diameter In Al-7wt% Si Alloy Directionally Solidified Aboard The International Space Station, S. R. Upadhyay, Surendra N. Tewari, M. Ghodes, R. N. Grugel, D. R. Poirier, M. Lauer Jan 2019

Primary Dendrite Trunk Diameter In Al-7wt% Si Alloy Directionally Solidified Aboard The International Space Station, S. R. Upadhyay, Surendra N. Tewari, M. Ghodes, R. N. Grugel, D. R. Poirier, M. Lauer

Chemical & Biomedical Engineering Faculty Publications

Under a NASA (National Aeronautics and Space Agency)-ESA (European Space Agency) collaborative research project, MICAST (Microstructure formation in casting of technical alloys under a diffusive and magnetically controlled convection conditions), three Al-7wt% Si samples (MICAST-6, MICAST-7 and MICAST2-12) were directionally solidified at growth speeds varying from 10 to 50 µm s-1 aboard the International Space Station to determine the effect of mitigating convection on the primary dendrite array. The observed primary dendrite trunk diameters during steady-state growth of MICAST samples show a good agreement with predictions from a coarsening based model developed by the authors. The trunk diameters in …


Design Of Embedded Wireless Sensors For Real-Time And In-Situ Strain Sensing Of Fiber Reinforced Composites, Relebohile George Qhobosheane, Sujjatul Islam, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider Jan 2019

Design Of Embedded Wireless Sensors For Real-Time And In-Situ Strain Sensing Of Fiber Reinforced Composites, Relebohile George Qhobosheane, Sujjatul Islam, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

The increasing demand of early detection of barely visible damage inside fiber reinforced polymer (FRP) composites has led to the development of advanced microsensors capable of measuring local strains and defects within FRP composites. One of the major challenges in this type of local structural health monitoring (SHM) is the development of embedded sensors which can be safely placed into FRP composites while maintaining their high strength and light weight. This paper presents the development and investigation of a set of wireless magnetostrictive sensors embedded within the FRP composites for in-situ and real-time monitoring of local strains inside the composites. …


Synthesis Of Cadmium Arsenide Semiconductor Nanoparticles, Superatomic Silver Clusters, And Silver Coordination Polymers, Sarthak Jashubhai Patel Jan 2019

Synthesis Of Cadmium Arsenide Semiconductor Nanoparticles, Superatomic Silver Clusters, And Silver Coordination Polymers, Sarthak Jashubhai Patel

Legacy Theses & Dissertations (2009 - 2024)

Nanomaterials have chemical, electronic, optical, and other properties distinct from their bulk counterparts. However, the atom-precise synthesis of these materials remains a challenge, leaving open many scientific questions regarding the size regime between nanoparticulate (quantum confined) and bulk character. In this work, efforts toward the synthesis of nanoparticulate and atom-precise metal and semimetal materials are described. The synthesis of II-V semiconductor Cd3As2 having a near-zero bandgap is discussed. Analysis by UV-Vis absorption spectroscopy and powder X-ray diffraction indicate the formation of material with unexpected crystallinity and absorption properties The interaction between the molecular source of As and the solvent was …


Investigation Of Optical Second Harmonic Generation From Si (100) With Process Tailored Surface & Embedded Ag Nanostructures For Advanced Si Nonlinear Nanophotonics, Gourav Bhowmik Jan 2019

Investigation Of Optical Second Harmonic Generation From Si (100) With Process Tailored Surface & Embedded Ag Nanostructures For Advanced Si Nonlinear Nanophotonics, Gourav Bhowmik

Legacy Theses & Dissertations (2009 - 2024)

The challenge of current microelectronic architecture in transmission bandwidth and power consumption can be potentially solved by using silicon photonics technologies that are compatible with modern CMOS fabrication. One of the critical active photonic devices for Si photonics is a Si based optical modulator. Most of the reported silicon modulators rely on the free carrier plasma dispersion effect. In those cases, a weak change of the refractive index obtained by carrier accumulation, injection or depletion is utilized in a Mach-Zehnder interferometer or a microring resonator to achieve intensity modulation, rendering them difficult for chip-level implementation due to a large footprint …


Cvd Molybdenum Disulfide : Material And Device Engineering, Eui Sang Song Jan 2019

Cvd Molybdenum Disulfide : Material And Device Engineering, Eui Sang Song

Legacy Theses & Dissertations (2009 - 2024)

Molybdenum disulfide (MoS2) is a semiconducting 2D layered material that has attracted a lot of attention due to its material properties for electronics and optoelectronics device applications. These include a layer-dependent band gap, an indirect to direct energy transition at monolayer state, and strong light-matter interaction. A large majority of 2D materials and devices have been studied through micromechanical exfoliation for extraction and electron beam lithography for device fabrication. These methodologies while able to generate high quality materials and precisely fabricated devices, are not suitable for large scale production. Efforts have been made to make MoS2 and other 2D materials …


Low Energy Electron Interactions With Aliphatic And Aromatic Self-Assembled Monolayers On Au(111), Jodi Marie Grzeskowiak Jan 2019

Low Energy Electron Interactions With Aliphatic And Aromatic Self-Assembled Monolayers On Au(111), Jodi Marie Grzeskowiak

Legacy Theses & Dissertations (2009 - 2024)

Understanding the interaction of low energy electrons with organic thin films is important for the development of many technological applications, one of which is extreme ultra-violet (EUV, 92 eV) lithography. At this energy, the photon will produce an electron cascade that induces most of the chemical changes within the photoresist. In order to better understand these interactions, electron scattering experiments have been performed on self-assembled monolayers (SAMs) of the aliphatic molecule 1-decanethiol and the aromatic molecule 1,1’-biphenyl-4-thiol grown on Au(111) via vapor phase deposition. The molecules take on either a lying down (LD) or standing up (SU) geometry depending on …


Synthesis And Adsorption Experiments With Metal-Organic Frameworks For High School And Undergraduate Laboratory Settings, Kate Holley Jan 2019

Synthesis And Adsorption Experiments With Metal-Organic Frameworks For High School And Undergraduate Laboratory Settings, Kate Holley

Legacy Theses & Dissertations (2009 - 2024)

Seven experiments are described and outlined here that introduce high school and undergraduate students to metal–organic frameworks (MOFs) and their applications. The experiments were designed to be completed with basic laboratory equipment and supplies and without the use of expensive characterization instruments, simulating typical high school chemistry laboratory conditions. Students synthesized two well-known MOFs, HKUST-1 and aluminum fumarate, using simple, safe, and rapid methods (fast enough to be performed within the time constrains of a typical high school class). Students then use their synthesized MOFs to explore their inherent sorption properties. In one set of experiments, the synthesized MOFs are …


Phase Interaction Induced Texture In A Plasma Sprayed-Remelted Nicrbsi Coating During Solidification: An Electron Backscatter Diffraction Study, Liang-Yu Chen, Tianxiang Xu, Haiyang Wang, Peng Sang, Sheng Lu, Ze-Xin Wang, Shujin Chen, Lai-Chang Zhang Jan 2019

Phase Interaction Induced Texture In A Plasma Sprayed-Remelted Nicrbsi Coating During Solidification: An Electron Backscatter Diffraction Study, Liang-Yu Chen, Tianxiang Xu, Haiyang Wang, Peng Sang, Sheng Lu, Ze-Xin Wang, Shujin Chen, Lai-Chang Zhang

Research outputs 2014 to 2021

Although considerable endeavors have been dedicated to investigate the microstructures of the remelting-enhanced NiCrBSi coatings, the textures in the remelted coatings, which may result in property anisotropy, are rarely studied. In this work, the recrystallized fractions, grain orientations and interphase boundaries for Ni, Ni3B and CrB in a plasma sprayed-remelted NiCrBSi coating were investigated by electron backscatter diffraction. The results demonstrate that the texture is induced by phase interaction during solidification. Cooling from the liquid, the firstly formed Ni grains possess a cube fiber texture of {001}〈001〉. The successively formed Ni3B colonies are randomly oriented and …


Immune Modulation By Amphiphilic Oligonucleotides, Chunsong Yu Jan 2019

Immune Modulation By Amphiphilic Oligonucleotides, Chunsong Yu

Wayne State University Dissertations

Immunotherapy is emerging as one of the most promising therapeutic strategies for cancer treatment in clinical practice. Immunotherapy leverages the host’s immune system to attack and kill tumor cells. Rationally-designed cancer vaccines are emerging as one of the powerful immunotherapies primarily because of the promise of inducing tumor antigen-specific immune responses. To improve immunogenicity of cancer vaccines, vaccine antigens are administered with vaccine adjuvants which can robustly activate innate immune system and subsequently lead to adaptive immune response. However, the major challenge of achieving significant therapeutic efficacy is lack of efficient targeted-delivery of vaccine components. By taking advantage of endogenous …


Novel Cathode Framework, Effective Electrolyte Modification, And Electrode Structural Modification Of High Performance Lithium Sulfur Batteries, Wenduo Zeng Jan 2019

Novel Cathode Framework, Effective Electrolyte Modification, And Electrode Structural Modification Of High Performance Lithium Sulfur Batteries, Wenduo Zeng

Wayne State University Dissertations

Firstly, TiN nanotube arrays have been investigated as an effective skeleton in the cathode of lithium-sulfur batteries. A series of TiN nanotubes with various diameter and length have been synthesized and tested. Moreover, graphene nanoplatelets have been utilized as a structural anchor to support the TiN nanotubes, and the synergetic effect of composite material and its enhancement on Li-S battery electrochemical performance and cycling stability have been studied. Secondly, the improvement of electrode structural design has been evaluated for their effectiveness by using an in-situ characterization method with other electrochemical characterization. Lastly, the facile method of using transition metal cations …


Direct Laser Metal Deposition Of Nickel Based Superalloys, Abhishek Ramakrishnan-Sudha Jan 2019

Direct Laser Metal Deposition Of Nickel Based Superalloys, Abhishek Ramakrishnan-Sudha

Wayne State University Dissertations

Nickel-based superalloys are substantially used in the manufacturing of boilers for ultra-supercritical power plants and gas turbine hot-section as this grade of alloys provide higher yield strength with the rise in operating temperature and pressure owing to the presence of γʹ second phase precipitates. Conventionally, casting techniques such as centrifugal casting, investment casting, vacuum molding and several other casting based methods are used to fabricate the hot-section components. Nevertheless, a need for designing advanced materials with complex designs such as geometry, microstructure control, compositional changes, microstructure and property varying with the location as in functionally graded materials is not viable …


Utilizing Of Magnesium Oxysulfate Binders For Additive Construction Applications, Hatem Hashem Al-Masaeid Jan 2019

Utilizing Of Magnesium Oxysulfate Binders For Additive Construction Applications, Hatem Hashem Al-Masaeid

Electronic Theses and Dissertations

This dissertation is serving multiple transdisciplinary top-notch material design and technological topics. It is a proof of concept of the feasibility of 3D printing using Magnesium Oxysulfate (MOS) binder as an alternative to the ordinary Portland cement (OPC) to be utilized in terrestrial and extraterrestrial additive construction (AC) fields. MOS paste and mortar are characterized physically, chemically, and mechanically. The characterization results conducted in this research show how MOS’s properties can be controlled to match the 3D printing requirements by manipulating the MOS’s ingredients proportions.


Characterization Of Nanostructure, Materials, And Electron Emission Performance Of Next-Generation Thermionic Scandate Cathodes, Xiaotao Liu Jan 2019

Characterization Of Nanostructure, Materials, And Electron Emission Performance Of Next-Generation Thermionic Scandate Cathodes, Xiaotao Liu

Theses and Dissertations--Chemical and Materials Engineering

Scandate cathodes, where scandia is added to the tungsten cathode pellets, have recently received substantial and renewed research interest owing to significantly improved electron emission capabilities at lower temperatures, as compared with conventional dispenser cathodes. However, there are several persistent issues including non-uniform electron emission, lack of understanding regarding scandium’s role in the emission mechanism, and unreliable reproducibility in terms of scandate cathode fabrication. As a result, scandate cathodes have not yet been widely implemented in actual vacuum electron devices (VEDs).

The surface structure and chemical composition of multiple scandate cathodes – prepared with the powder using the liquid-solid (L-S) …


Investigation Of Transition-Metal Ions In The Nickel-Rich Layered Positive Electrode Materials For Lithium-Ion Batteries, Shuang Gao Jan 2019

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 …


Synthesis, Design, And Evaluation Of The Fluorescent Detection Of Polychlorinated Biphenyls(Pcbs) In Aqueous System, Irfan Ahmad Jan 2019

Synthesis, Design, And Evaluation Of The Fluorescent Detection Of Polychlorinated Biphenyls(Pcbs) In Aqueous System, Irfan Ahmad

Theses and Dissertations--Chemical and Materials Engineering

The exposure to halogenated persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), has been linked to numerous inflammatory diseases, including diabetes, cancer and lowered immune response. PCBs have low solubility in water, and they interact with other contaminants, making their detection quite challenging. While, there have been several attempts at improving the ease of detection and sensing of PCBs, gas chromatography-mass spectrometry (GC-MS) remains the gold standard. However, despite its ubiquitous use, GC-MS is a challenging technique that requires high skill and careful sample preparation, which are time-consuming and costly. As such, there is still a need to develop …


Understanding The Structure-Property-Performance Relationship Of Silicon Negative Electrodes, Jiazhi Hu Jan 2019

Understanding The Structure-Property-Performance Relationship Of Silicon Negative Electrodes, Jiazhi Hu

Theses and Dissertations--Chemical and Materials Engineering

Rechargeable lithium ion batteries (LIBs) have long been used to power not only portable devices, e.g., mobile phones and laptops, but also large scale systems, e.g., electrical grid and electric vehicles. To meet the ever increasing demand for renewable energy storage, tremendous efforts have been devoted to improving the energy/power density of LIBs. Known for its high theoretical capacity (4200 mAh/g), silicon has been considered as one of the most promising negative electrode materials for high-energy-density LIBs. However, diffusion-induced stresses can cause fracture and, consequently, rapid degradation in the electrochemical performance of Si-based negative electrodes. To mitigate the detrimental effects …


Lignin-Derived Carbon And Nanocomposite Materials For Energy Storage Applications, Wenqi Li Jan 2019

Lignin-Derived Carbon And Nanocomposite Materials For Energy Storage Applications, Wenqi Li

Theses and Dissertations--Biosystems and Agricultural Engineering

With a growing demand for electrical energy storage materials, lignin-derived carbon materials have received increasing attention in recent years. As a highly abundant renewable carbon source, lignin can be converted to a variety of advanced carbon materials with tailorable chemical, structural, mechanical and electrochemical properties through thermochemical conversion (e.g. pyrolysis). However, the non-uniformity in lignin structure, composition, inter-unit linkages and reactivity of diverse lignin sources greatly influence lignin fractionation from plant biomass, the pyrolysis chemistry, and property of the resulting carbon materials.

To introduce a better use of lignocellulosic biomass to biofuels and co-products, it is necessary to find novel …


Enhanced Surface Integrity With Thermally Stable Residual Stress Fields And Nanostructures In Cryogenic Processing Of Titanium Alloy Ti-6al-4v, James R. Caudill Jan 2019

Enhanced Surface Integrity With Thermally Stable Residual Stress Fields And Nanostructures In Cryogenic Processing Of Titanium Alloy Ti-6al-4v, James R. Caudill

Theses and Dissertations--Mechanical and Aerospace Engineering

Burnishing is a chipless finishing process used to improve surface integrity by severe plastic deformation (SPD) of surface asperities. As surface integrity in large measure defines the functional performance and fatigue life of aerospace alloys, burnishing is thus a means of increasing the fatigue life of critical components, such as turbine and compressor blades in gas turbine engines. Therefore, the primary objective of this dissertation is to characterize the burnishing-induced surface integrity of Ti-6Al-4V alloy in terms of the implemented processing parameters. As the impact of cooling mechanisms on surface integrity from SPD processing is largely unexplored, a particular emphasis …


Design And Process Of 3d-Printed Parts Using Composite Theory, Jordan Garcia Jan 2019

Design And Process Of 3d-Printed Parts Using Composite Theory, Jordan Garcia

Theses and Dissertations--Mechanical and Aerospace Engineering

3D printing is a revolutionary manufacturing method that allows the productions of engineering parts almost directly from modeling software on a computer. With 3D printing technology, future manufacturing could become vastly efficient. However, it is observed that the procedures used in 3D printing differ substantially among the printers and from those used in conventional manufacturing. In this thesis, the mechanical properties of engineering products fabricated by 3D printing were comprehensively evaluated and then compared with those made by conventional manufacturing. Three open-source 3D printers, i.e., the Flash Forge Dreamer, the Tevo Tornado, and the Prusa, were used to fabricate the …


Magnetic Domain Structures In Fe-Ga Alloys, Matthew N. Tianen Jan 2019

Magnetic Domain Structures In Fe-Ga Alloys, Matthew N. Tianen

Dissertations, Master's Theses and Master's Reports

Fe-Ga alloys, also referred to as Galfenol, have attracted great attention as new giant magnetostrictive materials for over fifteen years. They exhibit large magnetostriction, small hysteresis, good machinability, and high tensile strength, providing many advantages over other functional materials like magnetostrictive Terfenol-D, piezoelectric PZT, and magnetic shape memory Ni-Mn-Ga. In spite of the intense interest in Fe-Ga alloys, the domain phenomena that underlie their properties and functionalities are less known. Using the Bitter method, a systematic study of magnetic domain structures in Fe-Ga single crystals of different compositions and heat treatments has been performed. Our domain observation experiments reveal numerous …


Effect Of Development Of Scandium Trialuminide Precipitates On Corrosion And Mechanical Behavior In Aluminum-Magnesium Alloys, Carson Williams Jan 2019

Effect Of Development Of Scandium Trialuminide Precipitates On Corrosion And Mechanical Behavior In Aluminum-Magnesium Alloys, Carson Williams

Dissertations, Master's Theses and Master's Reports

Development of aluminum alloys has seen an increase in attention in recent years. The 5xxx series of Al-Mg alloys has the potential to provide strong, lightweight materials in various industry applications, however issues with strain formability and corrosion hinder the development of these alloys. The addition of Sc for developing Al3Sc precipitates provides considerable precipitation strengthening as well as grain refinement characteristics that can help mitigate these issues. Alloys with varied Mg content were analyzed for heat treatment aging responses and precipitate formation, changes in mechanical behavior related to the Portevin-le Chatelier effect, and effects on intergranular corrosion …


Investigating Microalloying Elements To Accelerate Zirconium Trialuminide Precipitation In Aluminum Alloys, Philip D. Staublin Jan 2019

Investigating Microalloying Elements To Accelerate Zirconium Trialuminide Precipitation In Aluminum Alloys, Philip D. Staublin

Dissertations, Master's Theses and Master's Reports

Precipitation of the L12-structured coherent Al3Zr trialuminide phase in aluminum-zirconium alloys increases the alloy strength. Precipitation of a more refined dispersion of Al3Zr can further increase the strength of these alloys. The addition of microalloying elements which bind to zirconium may accelerate the precipitation kinetics, allowing for nucleation of a greater number of precipitates and faster precipitate growth. Zirconium binding energies are computed for a wide range of elements, based on which the elements tin, antimony, and tellurium were selected for investigation. Ternary Al-Zr-X alloys (X = Sn, Sb, Te) were cast and heat …


Uv-Curable Organic-Inorganic Hybrid Polyurethane Coating, Shiyin Yu Jan 2019

Uv-Curable Organic-Inorganic Hybrid Polyurethane Coating, Shiyin Yu

Master's Theses and Doctoral Dissertations

This thesis explored a series of organic-inorganic hybrid polyurethane oligomers with varying molecular weights and functional groups (acrylate and/or silane) that were cured with a single ultraviolet (UV) trigger but two photo-initiators. Upon UV irradiation, the free-radical initiator initiated a free-radical reaction for acrylate cross-linking, and the photo-latent base initiated a sol-gel reaction for condensation of the silanes. This study explored the cure extent of both reactions by FTIR for acrylates and silanes and a weight-loss method for silanes as a function of functional group concentration and time. The general film properties were also studied. The results showed that the …


Experimental And Numerical Simulation Of Split Hopkinson Pressure Bar Test On Borosilicate Glass, Mayank K. Bagaria Jan 2019

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 …


Integrated Computational Materials Engineering (Icme) Investigation Of Electrical Conductivity And Thermodynamic Stability For Precipitation Strengthened Al-Zn-Zr And Al-Zn-Ni Ternary Alloys, Oladeji Fadayomi Jan 2019

Integrated Computational Materials Engineering (Icme) Investigation Of Electrical Conductivity And Thermodynamic Stability For Precipitation Strengthened Al-Zn-Zr And Al-Zn-Ni Ternary Alloys, Oladeji Fadayomi

Dissertations, Master's Theses and Master's Reports

High electrical conductivity Al-Zn-TM (TM=Transition metals) alloys with improved mechanical properties and thermal resistance are developed with an integrated computational material engineering (ICME) strategy. From a series of ab initio density functional theory (DFT) simulations assessing combinations of ternary alloys, Al-Zn-Ni and Al-Zn-Zr are determined as alloys with relatively high electrical conductivity compared to several other ternary Al alloy combinations. The zero-temperature stable structure of precipitates formed in these alloys are determined from computed enthalpy of formation as L12, with particular focus of examining the influence of Zn on stabilizing the desired L12 precipitate phase.

Scanning transmission …


Investigation Of Nano-Ceria Catalyst Infiltration Of Solid Oxide Fuel Cell (Sofc) Electrodes Using Bio-Inspired Catechol Surfactants, Ozcan Ozmen Jan 2019

Investigation Of Nano-Ceria Catalyst Infiltration Of Solid Oxide Fuel Cell (Sofc) Electrodes Using Bio-Inspired Catechol Surfactants, Ozcan Ozmen

Graduate Theses, Dissertations, and Problem Reports (ETD)

Development of solid oxide fuel cell (SOFC) electrodes with nano-structured grains can show enhanced power density with high catalytic activity owing to the higher surface area to volume ratio of the particles. However, the addition of nano-particles during the conventional electrode manufacturing process causes inevitable structural changes due to the coarsening of nano-particles at sintering temperatures. Wet impregnation/ infiltration methods are a practical and well-utilized method to form nanoparticles within the porous electrode microstructure of solid oxide fuel cells (SOFC) which requires relatively low calcination temperatures. Critical factors that impact the reduction of the electrode polarization using the nano-catalyst impregnation …


Enhancing The Thermoelectric Performance Of Calcium Cobaltite Ca3co4o9 Through Single And Dual Elements Doping, Cesar Octavio Romo De La Cruz Jan 2019

Enhancing The Thermoelectric Performance Of Calcium Cobaltite Ca3co4o9 Through Single And Dual Elements Doping, Cesar Octavio Romo De La Cruz

Graduate Theses, Dissertations, and Problem Reports (ETD)

Worldwide energy consumption losses more than 60% of the energy after its conversion, most of these losses are in the form of waste heat. Therefore, it is a matter of utmost importance to harness waste heat and reutilize this energy source to improve the overall conversion efficiency. Thermoelectric (TE) technology is one of the rising alternatives to harvest the excessive amount of energy lost as waste heat for a better and sustainable energy future. TE materials can utilize waste heat to improve efficiency in the ever-increasing demand for energy by converting a temperature difference directly into electricity due to the …


Engineering Plasmonic Nanostructures For Light Management And Sensing, Sujan Phani Kumar Kasani Jan 2019

Engineering Plasmonic Nanostructures For Light Management And Sensing, Sujan Phani Kumar Kasani

Graduate Theses, Dissertations, and Problem Reports (ETD)

The two major global problems are to provide health safety and to meet energy demands for ever growing population on a large scale. The study of light interaction with nanostructures has shown a promising solution in improving the fields of bio-sensor and solar energy devices which addresses above mentioned two major global problems. Nanostructures have tunable physicochemical properties such as light absorption, electrical and thermal properties unlike bulk materials, which gives an advantage in applications like bio-sensing and energy harvesting devices. The development of nanofabrication techniques along with the discovery of Surface Enhanced Raman Scattering (SERS) and Plasmon Enhanced Fluorescence …


Reflectivity And Photoemission Electron Microscopy Studies Of Magnetic Heterostructures, Chih-Yeh Huang Jan 2019

Reflectivity And Photoemission Electron Microscopy Studies Of Magnetic Heterostructures, Chih-Yeh Huang

Graduate Theses, Dissertations, and Problem Reports (ETD)

When a thin film thickness becomes ultrathin, the magnetic properties of the thin film can be altered, degraded or even lost. The loss of magnetism has been called the magnetic dead layer (MDL). Considering the trend for miniaturization of information storage and other devices, the MDL is a significant challenge for materials science and engineering. La1-xSrxMnO3 (LSMO) with x=0.3 is an excellent model material that exhibits ferromagnetism at room temperature to study the MDL. This dissertation focuses on understanding the MDL in LSMO films on their own and the effect of this dead layer when …