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Full-Text Articles in Physics
The Thermoelectric Properties Investigation Of X0.05Mo3Sb7-YTeY (X=Mn, Fe, Ni, Co; Y=1.5, 1.6, 1.7), Tim Holgate
The Thermoelectric Properties Investigation Of X0.05Mo3Sb7-YTeY (X=Mn, Fe, Ni, Co; Y=1.5, 1.6, 1.7), Tim Holgate
All Theses
With ever increasing energy costs, dwindling resources, and terms with the prefix 'green' filling headlines, the need for environmentally friendly energy sources has never been greater. Since the mid-20th century researchers have been pursuing greater efficiency in thermoelectric materials. Thermoelectric materials achieve energy conversion via the Seebeck effect (heat to electric power) and the Peltier effect (electricity to cooling power). Presented herein are the measured electrical and thermal transport properties and phenomenal analysis of the Ir3Ge7-type system: X0.05Mo3Sb7-yTey (X=Mn, Fe, Ni, Co; y=1.5, 1.6, 1.7) where 'X' are interstitially …
Calculations Of Diffusion In Fcc Binary Alloys Using On-The-Fly Kinetic Monte Carlo, Erdi Bleda
Calculations Of Diffusion In Fcc Binary Alloys Using On-The-Fly Kinetic Monte Carlo, Erdi Bleda
All Dissertations
With the recent advancements in computer technologies and the improvements in simulation algorithms, along with the theories, has allowed scientists to carry out diffusion calculations more efficiently, especially for the cases where either the diffusion itself takes longer, or there is no available isotope to carry out the diffusion experiments such as tracer diffusion.
In this work, we present a systematic approach to diffusion in intermetallic alloys such as weakly clustered Cu — Ni and weakly ordered Au — Ag. We use Accelerated Molecular Dynamics (AMD) combined with the Embedded Atom Method (EAM) to find the necessary saddlepoint energies. With …
The Origin Of The 511 Kev Positron Annihilation Emission Morphology, Bethany Johns
The Origin Of The 511 Kev Positron Annihilation Emission Morphology, Bethany Johns
All Theses
The 511 keV positron annhilation emission from the Galactic bulge has yet to solely be attributed to any astrophysical source of positrons. The 511 keV line, characteristic of electron-positron annihilation, was discovered in 1970 by Johnson and Haymes [1973] almost 40 years ago. Most recently the INTERnational Gamma-Ray Astrophysical Laboratory (INTEGRAL) [Knodlseder 1997] has measured the annihilation rates of both components of the Galaxy. The bulge and disk annihilation rates are (1.5 ± 0.1) x 10^43 e+ s^-1 and(0.3 ± 0.2) x 10^43 e+ s^-1, respectively. The ratio of the bulge rate to that of the disk ranges from 3-9. …
3-D Calculation Of Atom-Surface Collisions With Direct Scattering, Trapping And Desorption, Guoqing Fan
3-D Calculation Of Atom-Surface Collisions With Direct Scattering, Trapping And Desorption, Guoqing Fan
All Dissertations
In this work a scattering theory is developed to simulate the gas-surface scattering procedure in three dimensions, using an iterative algorithm and classical mechanics for the collision process, that describes both direct scattering and trapping-desorption of an incident beam of atomic particles. The initially trapped fraction of particles can be followed as they continue to make further collisions with the surface until they are all eventually promoted back into the positive energy continuum and leave the surface region.
With two different models, the discrete model and the smooth-surface model of the differential reflection coefficient, a series of calculation are made …
The Effects Of Nanoparticle Inclusions Upon The Microstructure And Thermoelectric Transport Properties Of Bismuth Telluride-Based Composites, Nick Gothard
All Dissertations
Research into materials that have high efficiencies of thermoelectric heat-energy conversion has been at a plateau since the middle of the last century. During this time, efficiencies have been engineered high enough for several interesting niche applications but not high enough for widespread adaptation into traditional power generation or refrigeration technologies. The past decade has seen considerable advancement as a number of theoretical works have suggested that lower dimensional structures could hold the key for enhanced efficiency, and several experiments have provided the proof of principle needed to inspire just such a research direction. The benefit of low dimensional structures …
Lead Chalcogenide Nano-Composites: Synthesis, Thermal And Electrical Transport Properties, Bo Zhang
Lead Chalcogenide Nano-Composites: Synthesis, Thermal And Electrical Transport Properties, Bo Zhang
All Dissertations
This dissertation focused on the investigation of the thermoelectric properties of PbTe nanocomposites, presenting a series of experimental investigation and qualitative theoretical analysis regarding utilizing the nanostructures to enhance the thermoelectrical properties. Three innovative synthesis techniques, which are related to fabricating nanocomposites, were developed. These three techniques are the size-selective growth of PbTe nanoparticles by a convection CVD technique, the nanolayer coating technique by hydrothermal method, and the alkali-metal-nano-surface-treatment. In the future, these techniques can be applied to many other thermoelectric material systems.
We proposed to use the grain boundary engineering technique route in the thermoelectric nanocomposite field and successfully …
Analysis Of The Nonlinear Vibrations Of Electrostatically Actuated Micro-Cantilevers In Harmonic Detection Of Resonance (Hdr), Jonathan Taylor
Analysis Of The Nonlinear Vibrations Of Electrostatically Actuated Micro-Cantilevers In Harmonic Detection Of Resonance (Hdr), Jonathan Taylor
All Theses
Micro- and nano-cantilevers have the potential to revolutionize physical, chemical, and biological sensing; however, an accurate and scalable detection method is required. In this work, a fully electrical actuation and detection method is presented, known as the Harmonic Detection of Resonance (HDR). In HDR, harmonic components of the current are measured to determine the cantilever's resonance frequency. These harmonics exist as a result of nonlinearities in the system, principally in the electrostatic actuation force. In order to better understand this rich harmonic structure, a theoretical investigation of the micro-cantilever is undertaken. Both a lumped parameter model and a more accurate …
Thermal Coulomb Drag In A Bi-Layer Semiconductor System, Florin Lung
Thermal Coulomb Drag In A Bi-Layer Semiconductor System, Florin Lung
All Theses
In this work, we investigate the existence of a thermoelectric effect that consists of the appearance of an electric field in one layer when a temperature gradient is applied in the other layer of a double quantum well system. This represents a generalization of the Seebeck effect to the case of two spatially separated electron systems allowed to interact only through the Coulomb repulsion. The induced electric field results from the momentum transfer between the electrons driven out of equilibrium by the temperature gradient and the electrons at rest in the passive layer, a mechanism known in the literature as …