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Articles 1 - 30 of 35
Full-Text Articles in Physics
Anomaly Detection On Small Wind Turbine Blades Using Deep Learning Algorithms, Bridger Altice, Edwin Nazario, Mason Davis, Mohammad Shekaramiz, Todd K. Moon, Mohammad A. S. Masoum
Anomaly Detection On Small Wind Turbine Blades Using Deep Learning Algorithms, Bridger Altice, Edwin Nazario, Mason Davis, Mohammad Shekaramiz, Todd K. Moon, Mohammad A. S. Masoum
Electrical and Computer Engineering Faculty Publications
Wind turbine blade maintenance is expensive, dangerous, time-consuming, and prone to misdiagnosis. A potential solution to aid preventative maintenance is using deep learning and drones for inspection and early fault detection. In this research, five base deep learning architectures are investigated for anomaly detection on wind turbine blades, including Xception, Resnet-50, AlexNet, and VGG-19, along with a custom convolutional neural network. For further analysis, transfer learning approaches were also proposed and developed, utilizing these architectures as the feature extraction layers. In order to investigate model performance, a new dataset containing 6000 RGB images was created, making use of indoor and …
Methods For Preparing And Characterizing Granular Materials For Electron Yield Measurements, Tom Keaton
Methods For Preparing And Characterizing Granular Materials For Electron Yield Measurements, Tom Keaton
All Graduate Plan B and other Reports, Spring 1920 to Spring 2023
This work presents a systematic study on sample preparation methods and accuracy of electron yield (EY) measurements of highly insulating, granular materials. EY measurements of highly insulating materials, especially those with high EY, are challenging due to the effects of sample charging even for very low fluence electron probe beams. EY measurements of particulates are complicated by: (i) roughness effects from particulate size, shape, coverage, and compactness; (ii) particle adhesion; (iii) substrate contributions; and (iv) electrostatic repulsion and potential barriers from charged particles and substrates. Numerous methods were explored to rigidly affix particles on conducting substrates at varying coverages for …
Introduction To Classical Field Theory, Charles G. Torre
Introduction To Classical Field Theory, Charles G. Torre
All Complete Monographs
This is an introduction to classical field theory. Topics treated include: Klein-Gordon field, electromagnetic field, scalar electrodynamics, Dirac field, Yang-Mills field, gravitational field, Noether theorems relating symmetries and conservation laws, spontaneous symmetry breaking, Lagrangian and Hamiltonian formalisms.
A Near Horizon Extreme Binary Black Hole Geometry, Jacob Ciafre, Maria J. Rodriguez
A Near Horizon Extreme Binary Black Hole Geometry, Jacob Ciafre, Maria J. Rodriguez
All Physics Faculty Presentations
A new solution of four-dimensional vacuum General Relativity is presented. It describes the near horizon region of the extreme (maximally spinning) binary black hole system with two identical extreme Kerr black holes held in equilibrium by a massless strut. This is the first example of a non-supersymmetric, near horizon extreme binary black hole geometry of two uncharged black holes. The black holes are co-rotating, their relative distance is fixed, and the solution is uniquely specified by the mass. Asymptotically, the geometry corresponds to the near horizon extreme Kerr (NHEK) black hole. The binary extreme system has finite entropy.
On The Balance Between Plasma And Magnetic Pressure Across Equatorial Plasma Depletions, J. Rodríguez-Zuluaga, C. Stolle, Y. Yamazaki, H. Lühr, J. Park, Ludger Scherliess, J. L. Chau
On The Balance Between Plasma And Magnetic Pressure Across Equatorial Plasma Depletions, J. Rodríguez-Zuluaga, C. Stolle, Y. Yamazaki, H. Lühr, J. Park, Ludger Scherliess, J. L. Chau
All Physics Faculty Publications
In magnetized plasmas such as the ionosphere, electric currents develop in regions of strong density gradients to balance the resulting plasma pressure gradients. These currents, usually known as diamagnetic currents decrease the magnetic pressure where the plasma pressure increases, and vice versa. In the low‐latitude ionosphere, equatorial plasma depletions (EPDs) are well known for their steep plasma density gradients and adverse effect on radio wave propagation. In this paper, we use continuous measurements of the magnetic field and electron density from the European Space Agency's Swarm constellation mission to assess the balance between plasma and magnetic pressure across large‐scale EPDs. …
Does The Black Hole Shadow Probe The Event Horizon Geometry?, Pedro V. P. Cunha, Carlos A. R. Herdeiro, Maria J. Rodriguez
Does The Black Hole Shadow Probe The Event Horizon Geometry?, Pedro V. P. Cunha, Carlos A. R. Herdeiro, Maria J. Rodriguez
All Physics Faculty Publications
There is an exciting prospect of obtaining the shadow of astrophysical black holes (BHs) in the near future with the Event Horizon Telescope. As a matter of principle, this justifies asking how much one can learn about the BH horizon itself from such a measurement. Since the shadow is determined by a set of special photon orbits, rather than horizon properties, it is possible that different horizon geometries yield similar shadows. One may then ask how sensitive is the shadow to details of the horizon geometry? As a case study, we consider the double Schwarzschild BH and analyze the impact …
How Hospitable Are Space Weather Affected Habitable Zones? The Role Of Ion Escape, Vladimir S. Airapetian, Alex Glocer, George V. Khazanov, Robert O Parke Loyd, Kevin France, Jan Josef Sojka, William C. Danchi, Michael W. Liemohn
How Hospitable Are Space Weather Affected Habitable Zones? The Role Of Ion Escape, Vladimir S. Airapetian, Alex Glocer, George V. Khazanov, Robert O Parke Loyd, Kevin France, Jan Josef Sojka, William C. Danchi, Michael W. Liemohn
All Physics Faculty Publications
Atmospheres of exoplanets in the habitable zones around active young G-K-M stars are subject to extreme X-ray and EUV (XUV) fluxes from their host stars that can initiate atmospheric erosion. Atmospheric loss affects exoplanetary habitability in terms of surface water inventory, atmospheric pressure, the efficiency of greenhouse warming, and the dosage of the UV surface irradiation. Thermal escape models suggest that exoplanetary atmospheres around active K-M stars should undergo massive hydrogen escape, while heavier species including oxygen will accumulate forming an oxidizing atmosphere. Here, we show that non-thermal oxygen ion escape could be as important as thermal, hydrodynamic H escape …
Climatology Of Plasmaspheric Total Electron Content Obtained From Jason 1 Satellite, Ja Soon Shim, Geonhwa Jee, Ludger Scherliess
Climatology Of Plasmaspheric Total Electron Content Obtained From Jason 1 Satellite, Ja Soon Shim, Geonhwa Jee, Ludger Scherliess
All Physics Faculty Publications
We used more than 40 million total electron content (TEC) measurements obtained from the GPS TurboRogue Space Receiver receiver on board the Jason 1 satellite in order to investigate the global morphology of the plasmaspheric TEC (pTEC) including the variations with local time, latitude, longitude, season, solar cycle, and geomagnetic activity. The pTEC corresponds to the total electron content between Jason 1 (1336 km) and GPS (20,200 km) satellite altitudes. The pTEC data were collected during the 7 year period from January 2002 to December 2008. It was found that pTEC increases by about 10–30% from low to high solar …
How Uncertainty In The Neutral Wind Limits The Accuracy Of Ionospheric Modeling And Forecasting, Michael David, Jan J. Sojka, Robert W. Schunk
How Uncertainty In The Neutral Wind Limits The Accuracy Of Ionospheric Modeling And Forecasting, Michael David, Jan J. Sojka, Robert W. Schunk
Publications
One of the most important input fields for an ionospheric model is the horizontal neutral wind. The primary mechanism by which the neutral wind affects ionospheric densities is the inducement of an upward or downward ion drift along the magnetic field lines; this affects the rate at which ions are lost through recombination. The magnitude of this effect depends upon the dip angle of the magnetic field; for this reason, the impact of the neutral wind is somewhat less in polar regions than at mid-latitudes. It is unfortunate that observations of the neutral wind are relatively scarce, as compared for …
Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos
Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos
Charles G. Torre
Rainich-type conditions giving a spacetime “geometrization” of matter fields in general relativity are reviewed and extended. Three types of matter are considered: perfect fluids, scalar fields, and electromagnetic fields. Necessary and sufficient conditions on a spacetime metric for it to be part of a perfect fluid solution of the Einstein equations are given. Formulas for constructing the fluid from the metric are obtained. All fluid results hold for any spacetime dimension. Geometric conditions on a metric which are necessary and sufficient for it to define a solution of the Einstein-scalar field equations and formulas for constructing the scalar field from …
Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos
Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos
Presentations and Publications
Rainich-type conditions giving a spacetime “geometrization” of matter fields in general relativity are reviewed and extended. Three types of matter are considered: perfect fluids, scalar fields, and elec- tromagnetic fields. Necessary and sufficient conditions on a spacetime metric for it to be part of a perfect fluid solution of the Einstein equa- tions are given. Formulas for constructing the fluid from the metric are obtained. All fluid results hold for any spacetime dimension. Ge- ometric conditions on a metric which are necessary and sufficient for it to define a solution of the Einstein-scalar field equations and for- mulas for constructing …
Perihelion Precession In General Relativity, Charles G. Torre
Perihelion Precession In General Relativity, Charles G. Torre
Charles G. Torre
This is a Maple worksheet providing a relatively quick and informal sketch of a demonstration that general relativistic corrections to the bound Kepler orbits introduce a perihelion precession. Any decent textbook will derive this result. My analysis aligns with that found in the old text "Introduction to General Relativity", by Adler, Bazin and Schiffer. The plan of the analysis is as follows. * Model the planetary orbits as geodesics in the (exterior) Schwarzschild spacetime. * Compute the geodesic equations. * Simplify them using symmetries and first integrals. * Isolate the differential equation expressing the radial coordinate as a function of …
The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre
The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre
Charles G. Torre
We give a set of local geometric conditions on a spacetime metric which are necessary and sufficient for it to be a null electrovacuum, that is, the metric is part of a solution to the Einstein-Maxwell equations with a null electromagnetic field. These conditions are restrictions on a null congruence canonically constructed from the spacetime metric, and can involve up to five derivatives of the metric. The null electrovacuum conditions are counterparts of the Rainich conditions, which geometrically characterize non-null electrovacua. Given a spacetime satisfying the conditions for a null electrovacuum, a straightforward procedure builds the null electromagnetic field from …
Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson
Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson
Browse All Undergraduate research
A topic often taught in introductory astronomy courses is the changing position of the Sun in the sky as a function of time of day, and season. The relevance and importance of this motion is explained in the context of seasons and the impact it has on human activities such as agriculture. The geometry of the ob- served motion in the sky is usually reduced to graphical representations and visualizations that can be difficult to render and grasp. Sometimes students are asked to observe the Suns changing motion and record their data, but this is a long-term project requiring several …
Understanding Light Pollution In And Around Tucson, Arizona, Rachel K. Nydegger
Understanding Light Pollution In And Around Tucson, Arizona, Rachel K. Nydegger
Browse All Undergraduate research
No abstract provided.
The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre
The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre
Presentations and Publications
We give a set of local geometric conditions on a spacetime metric which are necessary and sufficient for it to be a null electrovacuum, that is, the metric is part of a solution to the Einstein-Maxwell equations with a null electromagnetic field. These conditions are restrictions on a null congruence canonically constructed from the spacetime metric, and can involve up to five derivatives of the metric. The null electrovacuum conditions are counterparts of the Rainich conditions, which geometrically characterize non-null electrovacua. Given a spacetime satisfying the conditions for a null electrovacuum, a straightforward procedure builds the null electromagnetic field from …
Prospects For Observing Ultracompact Binaries With Space-Based Gravitational Wave Interferometers And Optical Telescopes., T. B. Littenberg, Shane L. Larson, G. Nelemans Department Of Astrophysics, Radboud University Nijmegen, N. J. Cornish
Prospects For Observing Ultracompact Binaries With Space-Based Gravitational Wave Interferometers And Optical Telescopes., T. B. Littenberg, Shane L. Larson, G. Nelemans Department Of Astrophysics, Radboud University Nijmegen, N. J. Cornish
All Physics Faculty Publications
Space-based gravitational wave interferometers are sensitive to the galactic population of ultra-compact binaries. An important subset of the ultra-compact binary popula- tion are those stars that can be individually resolved by both gravitational wave in- terferometers and electromagnetic telescopes. The aim of this paper is to quantify the multi-messenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher Information Matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 deg2 and bright enough to …
Characterizing Sky Variability For Multi-Messenger Astronomy, Rachel Nydegger
Characterizing Sky Variability For Multi-Messenger Astronomy, Rachel Nydegger
UCUR
Multi-messenger astronomy employs both electromagnetic and gravitational -wave detectors to paint a richer picture of celestial objects, providing more depth and information. The interferometers utilized for gravitational-wave observations receive input from very broad fields of view on the sky, typically a few square degrees. To have simultaneous electromagnetic observations (typically less than one square degree) requires innovative techniques for the telescopes to find the origin of radiation. One idea is to “tile” the view of the interferometer, using multiple telescopes to simultaneously point at different areas of the field to observe the source. One di"culty of this observing paradigm is …
Mapping Light Pollution At Utah State University, Rachel Nydegger, Shane L. Larson
Mapping Light Pollution At Utah State University, Rachel Nydegger, Shane L. Larson
Research on the Hill (Salt Lake City)
One of the beauties of modern civilization is seeing the city lighting at night. It provides a feeling of security and is indicative of the power and endeavors of humanity, but over-lighting is a form of pollution. Many outdoor light fixtures spread light in all directions, sending a majority of the light into the sky, away from where we want the light to be on the ground. This light spreading upward is not only wasted light, but it is wasted energy and money, destroys our ability to view the night sky, and has profound effects on nocturnal creatures. The direct …
Galaxy Inclination And Surface Brightness, Jordan C. Rozum, Shane L. Larson
Galaxy Inclination And Surface Brightness, Jordan C. Rozum, Shane L. Larson
Student Showcase
The distribution of spiral and bar galaxy inclination angles is expected to be uniform. However, analysis of several major galaxy catalogs shows this is not the case; galaxies oriented near edge-on are significantly more common in these catalogs. In an attempt to explain this discrepancy, we have developed a galaxy simulation code to compute the appearance of a spiral type galaxy as a function of its morphological parameters. We examine the dependence of observed brightness upon inclination angle by using smooth luminous mass density and interstellar medium (ISM) density distributions. The luminous mass component is integrated along a particular line …
Modeling Spiral Galaxy Luminosity Profiles, Jordan Rozum, Matt Garlock, Shane L. Larson, Bradley W. Carroll
Modeling Spiral Galaxy Luminosity Profiles, Jordan Rozum, Matt Garlock, Shane L. Larson, Bradley W. Carroll
Browse All Undergraduate research
The distribution of spiral and bar galaxy inclination an- gles is expected to be uniform. However, analysis of sev- eral major galaxy catalogs shows this is not the case; galaxies oriented near edge-on are significantly more common in these catalogs. In an attempt to explain this discrepancy, we have developed a galaxy simulation code to compute the appearance of a spiral type galaxy as a function of its morphological parameters. We examine the dependence of observed brightness upon inclination angle by using smooth luminous mass density and in- terstellar medium (ISM) density distributions. The lu- minous mass component is integrated …
Constraining The Black Hole Mass Spectrum With Gravitational Wave Observations – I. The Error Kernel, Danny C. Jacobs, Joseph E. Plowman, Ronald W. Hellings, Sachiko Tsuruta, Shane L. Larson
Constraining The Black Hole Mass Spectrum With Gravitational Wave Observations – I. The Error Kernel, Danny C. Jacobs, Joseph E. Plowman, Ronald W. Hellings, Sachiko Tsuruta, Shane L. Larson
All Physics Faculty Publications
Many scenarios have been proposed for the origin of the supermassive black holes (SMBHs) that are found in the centres of most galaxies. Many of these formation scenarios predict a high-redshift population of intermediate-mass black holes (IMBHs), with masses M• in the range 102≲M•≲ 105 M⊙. A powerful way to observe these IMBHs is via gravitational waves the black holes emit as they merge. The statistics of the observed black hole population should, in principle, allow us to discriminate between competing astrophysical scenarios for the origin and formation of SMBHs. However, …
Detecting A Stochastic Gravitational-Wave Background: The Overlap Reduction Function, Lee Samuel Finn, Shane L. Larson, Joseph D. Romano
Detecting A Stochastic Gravitational-Wave Background: The Overlap Reduction Function, Lee Samuel Finn, Shane L. Larson, Joseph D. Romano
All Physics Faculty Publications
Detection of a gravitational-wave stochastic background via ground or space-based gravitational-wave detectors requires the cross correlation of the response of two or more independent detectors. The cross correlation involves a frequency-dependent factor—the so-called overlap reduction function or Hellings-Downs curve—that depends on the relative geometry of each detector pair, i.e., the detector separations and the relative orientation of their antenna patterns (beams). An incorrect formulation of this geometrical factor has appeared in the literature, leading to incorrect conclusions regarding the sensitivity of proposed detectors to a stochastic gravitational-wave background. To rectify these errors and as a reference for future work we …
The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman
The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The purpose of this thesis is to investigate whether it is feasible to use Langmuir probes on pico-satellites flying in low Earth orbit over mid- to low-latitude geographic regions. Following chapters on the expected ionospheric conditions and an overview of Langmuir probe theory, a chapter addressing the difficulties involved with pico-satellite Langmuir probes is presented. Also, the necessary satellite-to-probe surface area requirements in order to achieve confidence in pico-satellite Langmuir probe data, for the orbital regions of interest to this thesis, are stated.
Gravitational Wave Bursts From The Galactic Massive Black Hole, Clovis Hopman, Marc Freitag, Shane L. Larson
Gravitational Wave Bursts From The Galactic Massive Black Hole, Clovis Hopman, Marc Freitag, Shane L. Larson
All Physics Faculty Publications
The Galactic massive black hole (MBH), with a mass of M•= 3.6 × 106 M⊙, is the closest known MBH, at a distance of only 8 kpc. The proximity of this MBH makes it possible to observe gravitational waves (GWs) from stars with periapse in the observational frequency window of the Laser Interferometer Space Antenna (LISA). This is possible even if the orbit of the star is very eccentric, so that the orbital frequency is many orders of magnitude below the LISA frequency window, as suggested by Rubbo, Holley-Bockelmann & Finn (2006). …
Semi-Relativistic Approximation To Gravitational Radiation From Encounters With Non-Spinning Black Holes, Jonathan R. Gair, Daniel J. Kennefick, Shane L. Larson
Semi-Relativistic Approximation To Gravitational Radiation From Encounters With Non-Spinning Black Holes, Jonathan R. Gair, Daniel J. Kennefick, Shane L. Larson
All Physics Faculty Publications
The capture of compact bodies by black holes in galactic nuclei is an important prospective source for low frequency gravitational wave detectors, such as the planned Laser Interferometer Space Antenna. This paper calculates, using a semirelativistic approximation, the total energy and angular momentum lost to gravitational radiation by compact bodies on very high eccentricity orbits passing close to a supermassive, nonspinning black hole; these quantities determine the characteristics of the orbital evolution necessary to estimate the capture rate. The semirelativistic approximation improves upon treatments which use orbits at Newtonian order and quadrupolar radiation emission, and matches well onto accurate Teukolsky …
Lisa Time-Delay Interferometry Zero-Signal Solution: Geometrical Properties, Massimo Tinto, Shane L. Larson
Lisa Time-Delay Interferometry Zero-Signal Solution: Geometrical Properties, Massimo Tinto, Shane L. Larson
All Physics Faculty Publications
Time-delay interferometry (TDI) is the data processing technique needed for generating interferometric combinations of data measured by the multiple Doppler readouts available onboard the three Laser Interferometer Space Antenna (LISA) spacecraft. Within the space of all possible interferometric combinations TDI can generate, we have derived a specific combination that has zero response to the gravitational wave signal, and called it the zero-signal solution (ZSS). This is a two-parameter family of linear combinations of the generators of the TDI space, and its response to a gravitational wave becomes null when these two parameters coincide with the values of the angles of …
Lisa Data Analysis: Source Identification And Subtraction, Neil J. Cornish, Shane L. Larson
Lisa Data Analysis: Source Identification And Subtraction, Neil J. Cornish, Shane L. Larson
All Physics Faculty Publications
The Laser Interferometer Space Antenna will operate as an AM-FM receiver for gravitational waves. For binary systems, the source location, orientation and orbital phase are encoded in the amplitude and frequency modulation. The same modulations spread a monochromatic signal over a range of frequencies, making it difficult to identify individual sources. We present a method for detecting and subtracting individual binary signals from a data stream with many overlapping signals.
Lisa, Binary Stars, And The Mass Of The Graviton, Curt Cutler, William A. Hiscock, Shane L. Larson
Lisa, Binary Stars, And The Mass Of The Graviton, Curt Cutler, William A. Hiscock, Shane L. Larson
All Physics Faculty Publications
We extend and improve earlier estimates of the ability of the proposed LISA (Laser Interferometer Space Antenna) gravitational wave detector to place upper bounds on the graviton mass mg by comparing the arrival times of gravitational and electromagnetic signals from binary star systems. We show that the best possible limit on mg obtainable this way is ∼50 times better than the current limit set by solar system measurements. Among currently known, well-understood binaries, 4U1820-30 is the best for this purpose; LISA observations of 4U1820-30 should yield a limit ≈3-4 times better than the present solar system bound. AM …
The Lisa Optimal Sensitivity, Thomas A. Prince, Massimo Tinto, Shane L. Larson, J. W. Armstrong
The Lisa Optimal Sensitivity, Thomas A. Prince, Massimo Tinto, Shane L. Larson, J. W. Armstrong
All Physics Faculty Publications
The multiple Doppler readouts available on the Laser Interferometer Space Antenna (LISA) permit simultaneous formation of several interferometric observables. All these observables are independent of laser frequency fluctuations and have different couplings to gravitational waves and to the various LISA instrumental noises. Within the functional space of interferometric combinations LISA will be able to synthesize, we have identified a triplet of interferometric combinations that show optimally combined sensitivity. As an application of the method, we computed the sensitivity improvement for sinusoidal sources in the nominal, equal-arm LISA configuration. In the part of the Fourier band where the period of the …