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Temperature And Variability Of Three Ionian Volcanoes, Daniel R. Allen Aug 2010

Temperature And Variability Of Three Ionian Volcanoes, Daniel R. Allen

Theses and Dissertations

Cassini spacecraft images of Io obtained during its flyby of Jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hotspots, Pillan, Wayland, and Loki. We found a maximum color temperature of 1130+/-289 K for Pillan and maximum color temperatures of 1297+/-289 K and 1387+/-287 K for Wayland and Loki, respectively. These temperatures are suggestive of basaltic lava. The temperatures with the best signal-to-noise ratios also suggested basaltic lava and were found to be 780+/-189 K, 1116+/-250 K, and 1017+/-177 K for Pillan, Wayland, and Loki, respectively. Pillan showed increased …


Reversible Record Breaking And Variability: Temperature Distributions Across The Globe, Amalia Anderson, Alexander Kostinski Aug 2010

Reversible Record Breaking And Variability: Temperature Distributions Across The Globe, Amalia Anderson, Alexander Kostinski

Department of Physics Publications

Based on counts of record highs and lows, and employing reversibility in time, an approach to examining natural variability is proposed. The focus is on intrinsic variability; that is, variance separated from the trend in the mean. A variability index α is suggested and studied for an ensemble of monthly temperature time series around the globe. Deviation of 〈α〉 (mean α) from zero, for an ensemble of time series, signifies a variance trend in a distribution-independent manner. For 15 635 monthly temperature time series from different geographical locations (Global Historical Climatology Network), each time series about a …


Robust Isothermal Electric Control Of Exchange Bias At Room Temperature, Xi He, Yi Wang, Christian Binek, Peter A. Dowben Jun 2010

Robust Isothermal Electric Control Of Exchange Bias At Room Temperature, Xi He, Yi Wang, Christian Binek, Peter A. Dowben

Christian Binek Publications

Voltage-controlled spin electronics is crucial for continued progress in information technology. It aims at reduced power consumption, increased integration density and enhanced functionality where non-volatile memory is combined with highspeed logical processing. Promising spintronic device concepts use the electric control of interface and surface magnetization. From the combination of magnetometry, spin-polarized photoemission spectroscopy, symmetry arguments and first-principles calculations, we show that the (0001) surface of magnetoelectric Cr2O3 has a roughness-insensitive, electrically switchable magnetization. Using a ferromagnetic Pd/Co multilayer deposited on the (0001) surface of a Cr2O3 single crystal, we achieve reversible, room-temperature isothermal switching of the exchange-bias field between positive …


Quantum Criticality Due To Incipient Phase Separation In The Two-Dimensional Hubbard Model, Ehsan Khatami, K. Mikelsons, D. Galanakis, A. Macridin, J. Moreno, R. Scalettar, M. Jarrell May 2010

Quantum Criticality Due To Incipient Phase Separation In The Two-Dimensional Hubbard Model, Ehsan Khatami, K. Mikelsons, D. Galanakis, A. Macridin, J. Moreno, R. Scalettar, M. Jarrell

Faculty Publications

We investigate the two-dimensional Hubbard model with next-nearest-neighbor hopping, t′, using the dynamical cluster approximation. We confirm the existence of a first-order phase-separation transition terminating at a second-order critical point at filling nc(t′) and temperature Tps(t′). We find that as t′ approaches zero, Tps(t′) vanishes and nc(t′) approaches the filling associated with the quantum critical point separating the Fermi liquid from the pseudogap phase. We propose that the quantum critical point under the superconducting dome is the zero-temperature limit of the line of second-order critical points.


The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman Jan 2010

The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman

Electronic Theses and Dissertations

This dissertation consists of two parts: research pertaining to the development of scalable pump techniques for gain guided index-antiguided fiber lasers and research relating to the development of passive athermalization schemes for solid state lasers. The first section primarily details the development of a side pump scheme that allows for power scaling of gain-guided index anti-guided fibers. While these fibers have been demonstrated in past research, none have used a pump technology capable of pumping with the efficiencies, uniformity, and necessary length to allow for scaling of the fiber lasers to high output powers. The side pumped scheme developed in …


Temperature And Frequency Dependent Conduction Mechanisms Within Bulk Carbon Nanotube Materials, John Simmons Bulmer Jan 2010

Temperature And Frequency Dependent Conduction Mechanisms Within Bulk Carbon Nanotube Materials, John Simmons Bulmer

Browse all Theses and Dissertations

The resistance of three types of bulk carbon nanotube (CNT) materials (floating catalyst CNT yarn, forest grown CNT yarn, and super acid spun CNT fiber) was measured from room temperature to 900 C. Fitting the curves to established conduction equations for disordered materials, competing conduction mechanisms pertaining to the material could be determined. Floating catalyst CNT yarn displayed both semiconductive and metallic isotropic behavior with a resistance minimum, similar to the behavior of crystalline graphite. It was found that, at room temperature, the semiconducting contribution-most likely junctions between CNTs-accounted for 99.99% of the overall resistance. The resistance of forest grown …