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- Mathematics, Physics, and Computer Science Faculty Articles and Research (4)
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Articles 1 - 22 of 22
Full-Text Articles in Physics
Logistic Curves, Extraction Costs And Peak Oil, Robert J. Brecha
Logistic Curves, Extraction Costs And Peak Oil, Robert J. Brecha
Physics Faculty Publications
Debates about the possibility of a near-term maximum in world oil production have become increasingly prominent over the past decade, with the focus often being on the quantification of geologically available and technologically recoverable amounts of oil in the ground. Economically, the important parameter is not a physical limit to resources in the ground, but whether market price signals and costs of extraction will indicate the efficiency of extracting conventional or nonconventional resources as opposed to making substitutions over time for other fuels and technologies. We present a hybrid approach to the peak-oil question with two models in which the …
Economics Of Nuclear Power And Climate Change Mitigation Policies, Nico Bauer, Robert J. Brecha, Gunnar Luderer
Economics Of Nuclear Power And Climate Change Mitigation Policies, Nico Bauer, Robert J. Brecha, Gunnar Luderer
Physics Faculty Publications
The events of March 2011 at the nuclear power complex in Fukushima, Japan, raised questions about the safe operation of nuclear power plants, with early retirement of existing nuclear power plants being debated in the policy arena and considered by regulators. Also, the future of building new nuclear power plants is highly uncertain. Should nuclear power policies become more restrictive, one potential option for climate change mitigation will be less available. However, a systematic analysis of nuclear power policies, including early retirement, has been missing in the climate change mitigation literature. We apply an energy economy model framework to derive …
Equilibrium Magnetic States In Individual Hemispherical Permalloy Caps, Robert Streubel, Volodymyr P. Kravchuk, Denis D. Sheka, Denys Makarov, Florian Kronast, Oliver G. Schmidt, Yuri Gaididei
Equilibrium Magnetic States In Individual Hemispherical Permalloy Caps, Robert Streubel, Volodymyr P. Kravchuk, Denis D. Sheka, Denys Makarov, Florian Kronast, Oliver G. Schmidt, Yuri Gaididei
Robert Streubel Papers
The magnetization distributions in individual soft magnetic permalloy caps on non-magnetic spherical particles with sizes ranging from 50 to 800nm are investigated. We experimentally visualize the magnetic structures at the resolution limit of the x-ray magnetic circular dichroism photoelectron emission microscopy (XMCD-PEEM). By analyzing the so-called tail contrast in XMCD-PEEM, the spatial resolution is significantly enhanced, which allowed us to explore magnetic vortices and their displacement on curved surfaces. Furthermore, cap nanostructures are modeled as extruded hemispheres to determine theoretically the phase diagram of equilibrium magnetic states. The calculated phase diagram agrees well with the experimental observations. © 2012 American …
Fast Super-Resolution Using An Adaptive Wiener Filter With Robustness To Local Motion, Russell C. Hardie, Kenneth J. Barnard
Fast Super-Resolution Using An Adaptive Wiener Filter With Robustness To Local Motion, Russell C. Hardie, Kenneth J. Barnard
Electrical and Computer Engineering Faculty Publications
We present a new adaptive Wiener filter (AWF) super-resolution (SR) algorithm that employs a global background motion model but is also robust to limited local motion. The AWF relies on registration to populate a common high resolution (HR) grid with samples from several frames. A weighted sum of local samples is then used to perform nonuniform interpolation and image restoration simultaneously. To achieve accurate subpixel registration, we employ a global background motion model with relatively few parameters that can be estimated accurately. However, local motion may be present that includes moving objects, motion parallax, or other deviations from the background …
Supersymmetric Quantum Mechanics And Solvable Models, Asim Gangopadhyaya, Jonathan Bougie, Jeffrey Mallow, C. Rasinariu
Supersymmetric Quantum Mechanics And Solvable Models, Asim Gangopadhyaya, Jonathan Bougie, Jeffrey Mallow, C. Rasinariu
Physics: Faculty Publications and Other Works
We review solvable models within the framework of supersymmetric quantum mechanics (SUSYQM). In SUSYQM, the shape invariance condition insures solvability of quantum mechanical problems. We review shape invariance and its connection to a consequent potential algebra. The additive shape invariance condition is specified by a difference-differential equation; we show that this equation is equivalent to an infinite set of partial differential equations. Solving these equations, we show that the known list of h-independent superpotentials is complete. We then describe how these equations could be extended to include superpotentials that do depend on h.
Electronics Development For The Cherenkov Telescope Array, Margaret C. Murphy, Justin Vandenbrouke
Electronics Development For The Cherenkov Telescope Array, Margaret C. Murphy, Justin Vandenbrouke
STAR Program Research Presentations
Gamma-ray astronomy promises to elucidate the highest-energy particle accelerators in the Universe, and could play a key role in identifying the nature of dark matter. The Cherenkov Telescope Array (CTA), currently in the research and development stage, will study and capture gamma-rays with an order of magnitude grater sensitivity than the instruments already in place. Each telescope in the array will be equipped with dozens of camera modules each containing four TeV Array Readout with GSa/s sampling and Event Trigger (TARGET) chips. TARGET 4 has many internal settings, several of which were tested and analyzed to achieve an optimal operating …
Magnetic Vortices On Closely Packed Spherically Curved Surfaces, Robert Streubel, Denys Makarov, Florian Kronast, Volodymyr Kravchuk, Manfred Albrecht, Oliver G. Schmidt
Magnetic Vortices On Closely Packed Spherically Curved Surfaces, Robert Streubel, Denys Makarov, Florian Kronast, Volodymyr Kravchuk, Manfred Albrecht, Oliver G. Schmidt
Robert Streubel Papers
We investigate the change of magnetic vortex states driven by curvature. The equilibrium state and magnetization reversal of soft magnetic permalloy (Py, Ni 80Fe 20) caps on self-assembled spherical particles with diameters of 100, 330, and 800 nm are investigated, revealing the vortex ground state for individual caps and closely packed cap arrays. The magnetic coupling between vortices is substantially reduced due to the shape of the cap as apparent in a much weaker dependence of the magnetization reversal process on the separation distance. Interestingly, the remaining coupling is still sufficiently large to introduce chirality frustrated vortex states …
Magnetic Ordering And Structural Phase Transition In Strained Ultrathin Srruo3/Srtio3 Superlattice, Mingquiang Gu, Xiaoshan Wu, Guoping Zhang
Magnetic Ordering And Structural Phase Transition In Strained Ultrathin Srruo3/Srtio3 Superlattice, Mingquiang Gu, Xiaoshan Wu, Guoping Zhang
Symposium 2012
No abstract provided.
Characterization Of A Thermal Reservoir For Consistent And Accurate Annealing Of High Sensitivity Thermoluminescence Dosimeters In Brachytherapy Dosimetry, William Patrick Donahue
Characterization Of A Thermal Reservoir For Consistent And Accurate Annealing Of High Sensitivity Thermoluminescence Dosimeters In Brachytherapy Dosimetry, William Patrick Donahue
Honors Scholar Theses
Unlike regular TLD, an accurate and consistent annealing of the high-sensitivity TLD at 240 ˚C for 15 minutes is challenging using conventional annealing ovens because the temperature in the oven chamber varies drastically over the 15-minute period after the opening (to put the TLD tray in) and closing of oven door. The temperature in the oven drops dramatically after the door is opened and ramps up gradually after the door is closed, often accompanied with significant temperature overshoot. Because an overshoot by more than 5 ˚C can significantly reduce the sensitivity of the TLD and the ramp-up profile varies with …
Out-Of-Surface Vortices In Spherical Shells, Volodymyr P. Kravchuk, Denis D. Sheka, Robert Streubel, Denys Makarov, Oliver G. Schmidt, Yuri Gaididei
Out-Of-Surface Vortices In Spherical Shells, Volodymyr P. Kravchuk, Denis D. Sheka, Robert Streubel, Denys Makarov, Oliver G. Schmidt, Yuri Gaididei
Robert Streubel Papers
The interplay of topological defects with curvature is studied for out-of-surface magnetic vortices in thin spherical nanoshells. In the case of an easy-surface Heisenberg magnet it is shown that the curvature of the underlying surface leads to a coupling between the localized out-of-surface component of the vortex with its delocalized in-surface structure, i.e., polarity-chirality coupling. © 2012 American Physical Society.
Using Radial Basis Functions To Interpolate Along Single-Null Characteristics, Maria Babiuc-Hamilton, Clyde E. Meador
Using Radial Basis Functions To Interpolate Along Single-Null Characteristics, Maria Babiuc-Hamilton, Clyde E. Meador
Physics Faculty Research
The Cauchy-Characteristic Extraction (CCE) technique is the most precise method available for the computation of the gravitational waves obtained from numerical simulations of binary black hole mergers. This technique utilizes the characteristic evolution to extend the simulation to null infinity, where the waveform is computed in inertial coordinates. Although we recently made CCE publicly available to the numerical relativity community, there is still room for improvement, and the most important is enhancing the overall accuracy of the code, by upgrading the numerical methods used for interpolation and differentiation. One of the most promising ways is to use the Radial Basis …
Parameterized Special Theory Of Relativity (Pstr), Florentin Smarandache
Parameterized Special Theory Of Relativity (Pstr), Florentin Smarandache
Branch Mathematics and Statistics Faculty and Staff Publications
We have parameterized Einstein’s thought experiment with atomic clocks, supposing that we knew neither if the space and time are relative or absolute, nor if the speed of light was ultimate speed or not. We have obtained a Parameterized Special Theory of Relativity (PSTR), first introduced in 1982. Our PSTR generalized not only Einstein’s Special Theory of Relativity, but also our Absolute Theory of Relativity, and introduced three more possible Relativities to be studied in the future. After the 2011 CERN’s superluminal neutrino experiments, we recall our ideas and invite researchers to deepen the study of PSTR, ATR, and check …
A Simple And Inexpensive Optical Technique To Help Students Visualize Mode Shapes, Thomas R. Moore, Ashley E. Cannaday, Sarah A. Zietlow
A Simple And Inexpensive Optical Technique To Help Students Visualize Mode Shapes, Thomas R. Moore, Ashley E. Cannaday, Sarah A. Zietlow
Student-Faculty Collaborative Research Publications
An imaging technique is introduced that is suitable for visualizing the mode shapes of vibrating structures in an educational setting. The method produces images similar to those obtained using electronic speckle pattern interferometry (ESPI) but it can be implemented for less than 1=10 the cost of a commercial ESPI system, and the apparatus is simple enough that it can be constructed by undergraduate students. This technique allows for real-time visualization of the normal modes and detection shapes of harmonically vibrating structures, including those with shapes that make generating Chladni patterns with sand or powder impossible. The theory of operation and …
Normal Modes Of The Indian Elephant Bell, Robert Perrin, Luke Chalmers, Daniel Elford, Gerry M. Swallowe, Thomas R. Moore
Normal Modes Of The Indian Elephant Bell, Robert Perrin, Luke Chalmers, Daniel Elford, Gerry M. Swallowe, Thomas R. Moore
Faculty Publications
The geometrical structure of the Indian elephant bell is presented and the requirements on its normal modes from group representation theory are described. These are in good agreement with the results of a finiteelement model (FEM) for a specific 16-tine case. The spectrum consists of a sequence of families of modes lying on saturation curves and so is completely different from those of conventional bells. Physical explanations for the occurrence of these families are presented in terms of the tines behaving as a closed loop of coupled cantilevers with constraints from the dome. Each family is found to consist of …
Review Of Ultrasound Elastography Quality Control And Training Test Phantoms, S. Cournane, Andrew Fagan, Jacinta Browne
Review Of Ultrasound Elastography Quality Control And Training Test Phantoms, S. Cournane, Andrew Fagan, Jacinta Browne
Articles
While the rapid development of ultrasound elastography techniques in recent decades has sparked its prompt implementation in the clinical setting adding new diagnostic information to conventional imaging techniques, questions still remain as to its full potential and efficacy in the hospital environment. A limited number of technical studies have objectively assessed the full capabilities of the different elastography approaches, perhaps due, in part, to the scarcity of suitable tissue-mimicking materials and appropriately designed phantoms available. Few commercially-available elastography phantoms possess the necessary test target characteristics or mechanical properties observed clinically, or indeed reflect the lesion-to-background elasticity ratio encountered during clinical …
Qpced2.0: A Computer Program For The Processing And Quantification Of Polycrystalline Electron Diffraction Patterns, Xingzhong Li
Qpced2.0: A Computer Program For The Processing And Quantification Of Polycrystalline Electron Diffraction Patterns, Xingzhong Li
Nebraska Center for Materials and Nanoscience: Faculty Publications
The processing and quantification of electron diffraction patterns have become vital in advanced electron crystallographic analysis work. A computer program, QPCED2.0, has been developed for the handling of selected-area electron diffraction patterns for polycrystalline materials. QPCED2.0 can be used to enhance the visibility of electron diffraction patterns, to convert electron diffraction patterns into intensity profiles, and to retrieve precisely the lattice d spacings and the integral intensities of the diffraction rings. The design and implementation of QPCED2.0 are elucidated and application examples are given.
Transverse Measurements Of Polarization In Optically Pumped Rb Vapor Cells, J. M. Dreiling, E. B. Norrgard, D. Tupa, Timothy J. Gay
Transverse Measurements Of Polarization In Optically Pumped Rb Vapor Cells, J. M. Dreiling, E. B. Norrgard, D. Tupa, Timothy J. Gay
Timothy J. Gay Publications
We have developed a simple heuristic method for determining the polarization of an optically pumped alkalimetal vapor. A linearly polarized probe beam traverses a vapor cell perpendicular to the pump-beam propagation direction, and the transmitted beam intensity is monitored for orthogonal linear polarizations. As the probe beam is scanned in frequency across the D1 transition, its linear-polarization-dependent transmission can be used as a measure of the atomic orientation of the vapor. We analyze these transmission differences and their dependence on the alkali-metal number density in the vapor.
Review Of Elegance And Enigma: The Quantum Interviews, Matthew S. Leifer
Review Of Elegance And Enigma: The Quantum Interviews, Matthew S. Leifer
Mathematics, Physics, and Computer Science Faculty Articles and Research
A review of Elegance and Enigma: The Quantum Interviews, edited by Maximilian Schlosshauer.
A Locking-Free Hp Dpg Method For Linear Elasticity With Symmetric Stresses, Jamie Bramwell, Leszek Demkowicz, Jay Gopalakrishnan, Weifeng Qiu
A Locking-Free Hp Dpg Method For Linear Elasticity With Symmetric Stresses, Jamie Bramwell, Leszek Demkowicz, Jay Gopalakrishnan, Weifeng Qiu
Mathematics and Statistics Faculty Publications and Presentations
We present two new methods for linear elasticity that simultaneously yield stress and displacement approximations of optimal accuracy in both the mesh size h and polynomial degree p. This is achieved within the recently developed discontinuous Petrov- Galerkin (DPG) framework. In this framework, both the stress and the displacement ap- proximations are discontinuous across element interfaces. We study locking-free convergence properties and the interrelationships between the two DPG methods.
Pbr, Epr, And All That Jazz, Matthew S. Leifer
Pbr, Epr, And All That Jazz, Matthew S. Leifer
Mathematics, Physics, and Computer Science Faculty Articles and Research
"In the past couple of months, the quantum foundations world has been abuzz about a new preprint entitled "The Quantum State Cannot be Interpreted Statistically" by Matt Pusey, Jon Barrett and Terry Rudolph (henceforth known as PBR). Since I wrote a blog post explaining the result, I have been inundated with more correspondence from scientists and more requests for comment from science journalists than at any other point in my career. Reaction to the result amongst quantum researchers has been mixed, with many people reacting negatively to the title, which can be misinterpreted as an attack on the Born rule. …
Response To Griffiths, Matthew S. Leifer
Response To Griffiths, Matthew S. Leifer
Mathematics, Physics, and Computer Science Faculty Articles and Research
"First of all, I would like to thank Prof. Griffith for his comments. The exchange has reminded me of the series of letters that appeared in Physics Today following the publication of an article by Chandralekha Singh, Mario Belloni, and Wolfgang Christian on improving the teaching of undergraduate quantum mechanics (see http://ptonline.aip.org/ journals/doc/PHTOAD-ft/vol_60/iss_3/8_1.shtml). In those responses, both Griffiths and Travis Norsen argued that students’ understanding of quantum mechanics would be vastly improved if they were taught more about the foundations of quantum theory, and I wholeheartedly agree with that sentiment. The thing is, Griffiths argued vociferously that this should be …
Review Of The Mathematical Language Of Quantum Theory: From Uncertainty To Entanglement, Matthew S. Leifer
Review Of The Mathematical Language Of Quantum Theory: From Uncertainty To Entanglement, Matthew S. Leifer
Mathematics, Physics, and Computer Science Faculty Articles and Research
A book review of The Mathematical Language of Quantum Theory: From Uncertainty to Entanglement by Teiko Heinosaari and Mario Ziman.