Numerical Modeling Of Tectonics And Fault Activity Of Icy Satellites,
2012
University of Texas at El Paso
Numerical Modeling Of Tectonics And Fault Activity Of Icy Satellites, John Olgin
Open Access Theses & Dissertations
Enceladus, one of the satellites of Saturn, exhibits evidence of recent fault activity, which may be due to gravitational fluctuations, or tidal stresses, generated by its orbit around Saturn. Recent Cassini spacecraft observations of Enceladus reveal water-ice plume activity at the south polar region, originating from locations that correlate with four geologically young, linear fracture-like features, named the "tiger stripes". It is the goal of this investigation to determine the ideal geophysical and geological factors (e.g., fault depths, frictional coefficients, ice layer thickness, ocean layer thickness, tidal stress sources) that support fault activity on Enceladus. The core of this work …
New Methods For The Discovery And Characterization Of Lunar Lava Tubes Using Lunar Reconnaissance Orbiter Data,
2012
University of Texas at El Paso
New Methods For The Discovery And Characterization Of Lunar Lava Tubes Using Lunar Reconnaissance Orbiter Data, Jonathan Arthur Meyer
Open Access Theses & Dissertations
Lava tubes have the potential to serve as a sustainable solution to long-term lunar habitation by providing protection from radiation and micrometeorite bombardment while potentially providing resources in the form of trapped water ice. They also pose compelling science targets in their own right. While the potential benefits of utilizing lunar lava tubes is clear, their discovery is less straightforward. Formation processes for lava tubes do not always result in a surface expression, making their discovery using remotely sensed imagery difficult. Furthermore, there is the potential for lava tubes to be covered by secondary lava flows, impact ejecta, or other …
High-Speed Acousto-Optic Shutter With No Optical Frequency Shift,
2012
Bucknell University
High-Speed Acousto-Optic Shutter With No Optical Frequency Shift, W J. Schwenger, James M. Higbie
Faculty Journal Articles
Acousto-optic modulators are widely used for rapid switching and shuttering of laser beams. In many applications, the concomitant frequency shift is undesirable and must be compensated for elsewhere in the system. Here we present a simple method of achieving rapid laser power switching without an accompanying laser frequency shift. The demonstrated acousto-optic shutter achieves a switching time of around 25 ns, an extinction ratio of 46 dB, and efficiency comparable to a conventional double-pass acousto-optical modulator configuration. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4746292]
Isometries And Spontaneous Lorentz Violation In General Relativity,
2012
Colby College
Isometries And Spontaneous Lorentz Violation In General Relativity, Greg Merritt
Honors Theses
General Relativity, or GR, is a theory which describes gravity as a manifestation of the curvature of space and time. While the other three fundamental forces in nature are represented as field theories, GR is a geometric theory. In the search for a way to reconcile the field theories for the electromagnetic, strong, and weak forces with the gravitational force, a logical place to start is by re-expressing GR as a field theory. In doing so, we find that the theory contains a number of symmetries. When we solve the equations in GR, we find that by choosing certain solutions …
The Late-Time Afterglow Of The Extremely Energetic Short Burst Grb 090510 Revisited,
2012
Roger Williams University
The Late-Time Afterglow Of The Extremely Energetic Short Burst Grb 090510 Revisited, A. Nicuesa Guelbenzu, S. Klose, T. Krühler, J. Greiner, A. Rossi, D.A. Kann, F. Olivares, A. Rau, P.M.J. Afonso, J. Elliott, R. Filgas, A. Küpcü Yoldas, S. Mcbreen, M. Nardini, P. Schady, S. Schmidl, V. Sudilovsky, Adria Updike, A. Yoldas
Arts & Sciences Faculty Publications
No abstract provided.
The Fast Evolution Of Sn 2010bh Associated With Xrf 100316d,
2012
Roger Williams University
The Fast Evolution Of Sn 2010bh Associated With Xrf 100316d, F. Olivares E., J. Greiner, P. Schady, A. Rau, S. Klose, T. Krühler, P.M.J. Afonso, Adria Updike, M. Nardini, R. Filgas, A. Nicuesa Guelbenzu, C. Clemens, J. Elliott, D.A. Kann, A. Rossi, V. Sudilovsky
Arts & Sciences Faculty Publications
No abstract provided.
Bl Lacertae Objects Beyond Redshift 1.3 – Uv-To-Nir Photometry And Photometric Redshift For Fermi/Lat Blazars,
2012
Roger Williams University
Bl Lacertae Objects Beyond Redshift 1.3 – Uv-To-Nir Photometry And Photometric Redshift For Fermi/Lat Blazars, A. Rau, P. Schady, J. Greiner, M. Salvato, M. Ajello, E. Bottacini, N. Gehrels, P.M.J. Afonso, J. Elliott, R. Filgas, D.A. Kann, S. Klose, T. Krühler, M. Nardini, A. Nicuesa Guelbenzu, F. Olivares E., A. Rossi, V. Sudilovsky, Adria Updike, D.H. Hartmann
Arts & Sciences Faculty Publications
Context. Observations of the γ-ray sky with Fermi led to significant advances towards understanding blazars, the most extreme class of active galactic nuclei. A large fraction of the population detected by Fermi is formed by BL Lacertae (BL Lac) objects, whose sample has always suffered from a severe redshift incompleteness due to the quasi-featureless optical spectra. Aims. Our goal is to provide a significant increase of the number of confirmed high-redshift BL Lac objects contained in the 2 LAC Fermi/LAT cataloge.Methods. For 103 Fermi/LAT blazars, photometric redshifts using spectral energy distribution fitting have been obtained.The photometry includes 13 broad-band filters …
Phase Estimation With Two-Mode Squeezed Vacuum And Parity Detection: Bayesian Analysis,
2012
Louisiana State University
Phase Estimation With Two-Mode Squeezed Vacuum And Parity Detection: Bayesian Analysis, Keith Motes
Honors Capstones
No abstract provided.
H2 Temperatures In The Crab Nebula,
2012
Michigan State University
H2 Temperatures In The Crab Nebula, E. D. Loh, J. A. Baldwin, Gary J. Ferland, Z. K. Curtis, C. T. Richardson, A. C. Fabian, P. Salomé
Physics and Astronomy Faculty Publications
We used K-band spectra to measure the H2 excitation temperatures in six molecular knots associated with the filaments in the Crab Nebula. The temperatures are quite high – in the range T∼ 2000–3000 K, just below the H2 dissociation temperature. This is the temperature range over which the H2 1–0 S(1) line at λ2.121 μm has its maximum emissivity per unit mass, so there may be many additional H2 cores with lower temperatures that are too faint to detect. We also measured the electron density in adjacent ionized gas, which on the assumption of …
Near Infrared Hydrogen Emission Line Ratios As Diagnostics Of The Broad Emission Line Region,
2012
University of Melbourne, Australia
Near Infrared Hydrogen Emission Line Ratios As Diagnostics Of The Broad Emission Line Region, Andrea J. Ruff, David J. E. Floyd, Kirk T. Korista, Rachel L. Webster, Ryan Lucian Porter, Gary J. Ferland
Physics and Astronomy Faculty Publications
Broad emission line flux ratios are a powerful diagnostic of the physical conditions of the broad-line region gas in Active Galactic Nuclei. With recent advances in infrared spectroscopy, previously unstudied emission lines provide a new means to investigate the physical nature of the BELR gas. The hydrogen emission lines are particularly sensitive to the upper limits of both the radius from the central ionising source and the number density of the gas. Using an existing subset of near-infrared quasar spectra from the Glikman et al. (2006) sample [1] together with Cloudy photoionization simulations, we confirm the Locally Optimally emitting Cloud …
Forty-Year Calibrated Record Of Earth-Reflected Radiance From Landsat: A Review,
2012
National Aeronautics and Space Administration, Biospheric Sciences Laboratory
Forty-Year Calibrated Record Of Earth-Reflected Radiance From Landsat: A Review, Brian L. Markham, Dennis L. Helder
United States National Aeronautics and Space Administration: Publications
Sensors on Landsat satellites have been collecting images of the Earth's surface for nearly 40 years. These images have been invaluable for characterizing and detecting changes in the land cover and land use of the world. Although initially conceived as primarily picture generating sensors, even the early sensors were radiometrically calibrated and spectrally characterized prior to launch and incorporated some capabilities to monitor their radiometric calibration once on orbit. Recently, as the focus of studies has shifted to monitoring Earth surface parameters over significant periods of time, serious attention has been focused toward bringing the data from all these sensors …
The Venus "Shell-Over-Star" Hieroglyph And Maya Warfare: An Examination Of The Interpretation Of A Mayan Symbol,
2012
Wayne State University
The Venus "Shell-Over-Star" Hieroglyph And Maya Warfare: An Examination Of The Interpretation Of A Mayan Symbol, Claudia Ann Voit
Wayne State University Theses
For decades, Maya scholars have associated the Mayan ―Shell-Star‖ (also referred to as ―Star-War‖) hieroglyph with Maya warfare. Put forward by scholars such as Floyd Lounsbury and David Kelley, and later advanced by Linda Schele, David Freidel, Ian Graham, Peter Matthews, Anthony Aveni and others, there are now dozens of published articles and chapters relating the hieroglyph to Venus and warfare. Venus is one of the most notable celestial objects outside of the Sun and Moon and was highly visible to the inhabitants of the Maya world. The Dresden Codex (an astronomical almanac) contains important information about the planet Venus, …
Tackling Gravity Wave Confusion Noise With Template Optimizers,
2012
The University of Texas Rio Grande Valley
Tackling Gravity Wave Confusion Noise With Template Optimizers, A. S. Stroeer, Matthew Benacquista
Physics & Astronomy Faculty Publications
The Mock LISA Data Challenge 4.0 simulated the joint two-year recording of gravitational wave signals from mergers of spinning black holes, extreme mass ratio inspirals, Galactic white dwarf binaries, bursts from cosmic strings, and a stochastic background—all over LISA instrument noise. We analysed this data using a global multi-start box and bound optimization scheme, incorporating multi-dimensional Nelder Mead simplex 2 optimization. Our scheme identified 2658 binaries. Of these, 2246 were found to systematically decompose the power in a strong spinning black hole merger into a "white dwarf binary transform". The remaining 416 binaries were identified with a false alarm rate …
Controlling Calibration Errors In Gravitational-Wave Detectors By Precise Location Of Calibration Forces,
2012
The University of Texas Rio Grande Valley
Controlling Calibration Errors In Gravitational-Wave Detectors By Precise Location Of Calibration Forces, Hernan P. Daveloza, M Afrin Badhan, Mario C. Diaz, K. Kawabe, P. N. Konverski, M. Landry, R. L. Savage
Physics & Astronomy Faculty Publications
We present results of finite element analysis simulations which could lead to more accurate calibration of interferometric gravitational wave detectors. Calibration and actuation forces applied to the interferometer test masses cause elastic deformation, inducing errors in the calibration. These errors increase with actuation frequency, and can be greater than 50% at frequencies above a few kilohertz. We show that they can be reduced significantly by optimizing the position at which the forces are applied. The Advanced LIGO [1] photon calibrators use a two-beam configuration to reduce the impact of local deformations of the test mass surface. The position of the …
The Characterization Of Virgo Data And Its Impact On Gravitational-Wave Searches,
2012
The University of Texas Rio Grande Valley
The Characterization Of Virgo Data And Its Impact On Gravitational-Wave Searches, J. Aasi, J. Abadie, Matthew Benacquista, G. Cagnoli, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Cristina V. Torres
Physics & Astronomy Faculty Publications
Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing …
Exceptional-Point Dynamics In Photonic Honeycomb Lattices With Pt Symmetry,
2012
The University of Texas Rio Grande Valley
Exceptional-Point Dynamics In Photonic Honeycomb Lattices With Pt Symmetry, Hamidreza Ramezani, Tsampikos Kottos, Vassilios Kovanis, Demetrios N. Christodoulides
Physics & Astronomy Faculty Publications
We theoretically investigate the flow of electromagnetic waves in complex honeycomb photonic lattices with local PT symmetries. Such PT structure is introduced via a judicious arrangement of gain and loss across the honeycomb lattice, characterized by a gain and loss parameter γ. We found a class of conical diffraction phenomena where the formed cone is brighter and travels along the lattice with a transverse speed proportional to √γ.
2.1Μm Emission Spectral Properties Of Tm And Ho Doped Transparent Yag Ceramic,
2012
University of Texas at San Antonio
2.1Μm Emission Spectral Properties Of Tm And Ho Doped Transparent Yag Ceramic, G. A. Kumar, Madhab Pokhrel
Physics & Astronomy Faculty Publications
Highly transparent Tm:Ho:YAG transparent ceramics were prepared using advanced ceramic technology and their spectroscopic properties were studied for infrared laser applications. Following the Judd-Ofelt procedure several spectroscopic properties such as the radiative transition probability (Arad), radiative decay time (τrad) and fluorescence branching ratio (β) are quantitatively obtained from the absorption spectrum. The absorption and emission cross sections corresponding to the 5I7 → 5I8 transition of Ho3+ at 2.1 μm have been evaluated following Mc Cumber theory and found that the obtained emission spectrum very well correlates to the simulated emission spectral data. The optical gain spectrum spread …
Screen-Printing Of Ferrite Magnetic Nanoparticles Produced By Carbon Combustion Synthesis Of Oxides,
2012
The University of Texas Rio Grande Valley
Screen-Printing Of Ferrite Magnetic Nanoparticles Produced By Carbon Combustion Synthesis Of Oxides, Karen S. Martirosyan, Gamage Dannangoda, Eduard Galstyan, Dmitri Litvinov
Physics & Astronomy Faculty Publications
The feasibility of screen-printing process of hard ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides (CCSO) is investigated. In CCSO, the exothermic oxidation of carbon generates a smolder thermal reaction wave that propagates through the solid reactant mixture converting it to the desired oxides. The complete conversion of hexaferrites occurs using reactant mixtures containing 11 wt. % of carbon. The BaFe12O19 and SrFe12O19 hexaferrites had hard magnetic properties with coercivity of 3 and 4.5 kOe, respectively. It was shown that the synthesized nanoparticles could be used to fabricate permanent magnet structures by consolidating them using screen-printing techniques.
Thermal Effects In The Input Optics Of The Enhanced Laser Interferometer Gravitational-Wave Observatory Interferometers,
2012
The University of Texas Rio Grande Valley
Thermal Effects In The Input Optics Of The Enhanced Laser Interferometer Gravitational-Wave Observatory Interferometers, K. L. Dooley, M. A. Arain, D. Fieldbaum, Volker Quetschke
Physics & Astronomy Faculty Publications
We present the design and performance of the LIGO Input Optics subsystem as implemented for the sixth science run of the LIGO interferometers. The Initial LIGO Input Optics experienced thermal side effects when operating with 7 W input power. We designed, built, and implemented improved versions of the Input Optics for Enhanced LIGO, an incremental upgrade to the Initial LIGO interferometers, designed to run with 30 W input power. At four times the power of Initial LIGO, the Enhanced LIGO Input Optics demonstrated improved performance including better optical isolation, less thermal drift, minimal thermal lensing, and higher optical efficiency. The …
On The Synthesis And Physical Properties Of Iron Doped Sno2 Nanoparticles,
2012
University of Nebraska - Lincoln
On The Synthesis And Physical Properties Of Iron Doped Sno2 Nanoparticles, X. Wei, R. Georgescu, N. Ali, I. Morjan, T. A. George, F. Dumitrache, R. Birjega, Mircea Chipara
Physics & Astronomy Faculty Publications
The synthesis of iron doped tin oxide by pulsed laser pyrolysis is reported. The as obtained nanoparticles have a dominant SnO2 phase (as revealed by Wide Angle X-ray Scattering), with particles of the order of 10 nm. The doping with iron or iron oxide triggers magnetic properties as confirmed by SQUID experiments. EDX measurements supported the presence of Fe while Wide Angle X-ray Scattering failed to sense any iron or iron-oxide phase. It is concluded that Fe is well dispersed within the tin-oxide nanoparticles. The coercitive field has a complex dependence on the Fe/Sn content suggesting that the magnetization is …
