Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 93 for “"Thermoelectrics"”.
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Thermoelectrics : material advancements and market applications
… yield a temperature differential. Interest in thermoelectrics laid dormant for almost 100 years and were primarily a laboratory curiosity. That interest was revived in the early 1900s with applications for remote power generation aboard satellites and several military applications. …
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Solar thermoelectrics for small scale power generation
… highest achieved value for concentrated solar thermoelectrics and it is comparable to photovoltaic modules that are deployed in these rural communities. Based on a heat transfer model developed during this work, various system parameters were analyzed for maximizing the performance. An …
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Thermoelectrics and aerogels for solar energy conversion systems
… and aerogel-based solar thermal receivers. Thermoelectrics are materials which produce a voltage when subjected to a temperature gradient. In a solar thermoelectric generator (STEG), sunlight heats one end of the thermoelectric materials, generating a voltage across the device. The voltage …
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Controlling microstructure of nanocrystalline thermoelectrics through powder processing
Bismuth Telluride and its solid solutions are currently front running thermoelectric materials because of their high figure of merit. When processed via mechanical alloying to obtain nanocrystalline structures, their efficiency is increased dramatically, due to enhanced phonon scattering at grain …
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Nanoscale heat conduction with applications in nanoelectronics and thermoelectrics
When the device or structure characteristic length scales are comparable to the mean free path and wavelength of energy carriers (electrons, photons, phonons, and molecules) or the time of interest is on the same order as the carrier relaxation time, conventional heat transfer theory is no longer …
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A Nanoengineering Approach to Oxide Thermoelectrics For Energy Harvesting Applications
… energy economy. Profitable, energy-efficient thermoelectrics possess thermoelectric figures of merit ZT ≥ 1. We examined the effect of metal nanoparticle – oxide film interfaces on the thermal conductivity κ and Seebeck coefficient α in bilayer and multilayer thin film oxide thermoelectrics in …
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Nanoscale Thermoelectrics: A Study of the Absolute Seebeck Coefficient of Thin Films
<p>The worlds demand for energy is ever increasing. Likewise, the environmental impact of climate change due generating that energy through combustion of fossil fuels is increasingly alarming. Due to these factors new sources of renewable energies are constantly being sought out. Thermoelectric …
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Theoretical studies of compressed xenon oxides, tin selenide thermoelectrics, and defects in graphene
Enormous advances in computing power in recent decades have made it possible to perform accurate numerical simulations of a wide range of systems in condensed matter physics. At the forefront of this progress has been density functional theory (DFT), a very popular approach to tackling the …
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Thermal, Magnetic, and Electrical Properties of Thin Films and Nanostructures: From Magnetic Insulators to Organic Thermoelectrics
<p>Modern fabrication and growth techniques allow for the development of increasingly smaller and more complex solid state structures, the characterization of which require highly specialized measurement platforms. In this dissertation I present the development of techniques and instrumentation …
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Temperature And Pressure Effects On Elastic Properties Of Relaxor Ferroelectrics And Thermoelectrics: A Resonant Ultrasound Spectroscopy Study
Relaxor ferroelectric lead magnesium niobate-lead titanate (PMN-PT) material exhibits exceptional electromechanical properties. The material undergoes a series of structural phase transitions with changes in temperature and the chemical composition. The work covered in this dissertation seek to …
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Comprehensive Modeling of Novel Thermal Systems: Investigation of Cascaded Thermoelectrics and Bio-Inspired Thermal Protection Systems Performance
Thermal systems involve multiple components assembled to store or transfer heat for power, cooling, or insulation purpose, and this research focuses on modeling the performance of two novel thermal systems that are capable of functioning in environments subjected to high heat fluxes. The first …
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New Approaches To Chalcogenide Materials For Thermoelectrics: Lead Telluride-Based Nanostructures And Facile Synthesis Of Tetrahedrite And Doped Derivatives
<p>The overall purpose of this work is to address several of the roadblocks to use of thermoelectric materials for generation of electricity, namely inefficient processing of materials and low performance, commonly rated by the figure of merit, ZT=T2/tot. The ZT includes as the Seebeck …
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LOW DIMENSIONAL CARBON BASED ORGANIC THERMOELECTRIC COMPOSITES: SYNTHESIS, CHARACTERIZATION, AND PERFORMANCE
… nearly sixty years ago, the performance of thermoelectrics has seen little improvement. In recent years, slight improvements through the use of complex crystalline structures and nano arrays have renewed interest in thermoelectrics, however, their performance is still orders of magnitude …
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THEORY, FABRICATION, AND EXPERIMENTATION OF PHONONIC CRYSTALS IN MEMS AT MICRO/NANO SCALE: ENGINEERING OF THERMAL AND RF PHONONS TO APPLICATIONS IN THERMOELECTRICS AND MICRORESONATORS
<p>Phononic Crystals (PnCs) are novel materials comprised of a periodic structure of inclusions in a matrix. This periodic arrangement creates phononic bandgaps, and modifies phononic bandstructures of a material. Such a property offers promising applications at the micro and nano scales to …
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Novel thermoelectric materials development, existing and potential applications, and commercialization routes
Thermoelectrics (TE) are devices which can convert heat in the form of a temperature gradient into electricity, or alternatively generate and absorb heat when an electrical current is run through them. It was established in the 1950's that the effectiveness of a thermoelectric could approximately …
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NANOSCALE ENERGY TRANSPORT IN PHOTOVOLTAIC AND THERMOELECTRIC NANOMATERIALS
… film research, and later, nanocomposite thermoelectrics have been studied.
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Thermal, Electrical, and Spin Transport: Encompassing Low-Damping Ferromagnets and Antiferromagnetic/Ferromagnetic Heterostructures
… In response to these difficulties, the fields of thermoelectrics, spintronics, and spincaloritronics emerge as contemporary solutions, each presenting unique advantages. Thermoelectric devices, based on the Seebeck effect, other a passive, carbon-free energy generating solution from waste heat. …
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Understanding and designing carbon-based thermoelectric materials with atomic-scale simulations
… sustainable and clean energy. Nevertheless, thermoelectrics have long been too inefficient to be utilized due to the relatively low energy conversion efficiency of present thermoelectrics. One way to obtain improved efficiency is to optimize the so-called TE figure of merit, ZT = …
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Exploring electron and phonon transport at the nanoscale for thermoelectric energy conversion
… harmful working fluids. Recently, nanostructured thermoelectrics have demonstrated remarkably enhanced energy conversion efficiencies, primarily due to a reduction in lattice thermal conductivity. Despite these advances, much remains unknown about heat transport in these materials, and further …
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Effect of phonon transport on the Seebeck coefficient and thermal conductivity of silicon nanowire arrays
Thermoelectrics enable solid-state conversion of heat to electricity by the Seebeck effect, but must provide scalable and cost-effective technology for practical waste heat harvesting. This dissertation explores the thermoelectric properties of electrochemically etched silicon nanowires through …
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