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Articles 1 - 22 of 22
Full-Text Articles in Physics
Oh And Oi Airglow Layer Modulation By Ducted Shortperiod Gravity Waves: Effects Of Trapping Altitude, J. B. Snively, V. P. Pasko, Michael J. Taylor
Oh And Oi Airglow Layer Modulation By Ducted Shortperiod Gravity Waves: Effects Of Trapping Altitude, J. B. Snively, V. P. Pasko, Michael J. Taylor
All Physics Faculty Publications
Perturbations to the OH and OI [O(1S) 557.7 nm] airglow layers by ducted gravity waves near the Brunt-Väisälä period are investigated using a 2-D numerical model. Airglow signatures of these waves are strongly determined by perturbations of O, O3, and H, which exhibit peak densities near and above mesopause. Strong periodic vertical wind components of short-period gravity waves induce opposite relative density perturbations above and below the layer density peaks. Airglow signatures for ducted waves depend on the specific vertical shapes and altitudes of the wave packets relative to ambient species density profiles; waves perturbing …
Symmetric Criticality In Classical Field Theory, Charles G. Torre, Ian M. Anderson
Symmetric Criticality In Classical Field Theory, Charles G. Torre, Ian M. Anderson
All Physics Faculty Publications
This is a brief overview of work done by Ian Anderson, Mark Fels, and myself on symmetry reduction of Lagrangians and Euler-Lagrange equations, a subject closely related to Palais’ Principle of Symmetric Criticality. After providing a little history, I describe necessary and sufficient conditions on a group action such that reduction of a group-invariant Lagrangian by the symmetry group yields the correct symmetry-reduced Euler-Lagrange equations.
Polar Mesospheric Cloud Structures Observed From The Cloud Imaging And Particle Size Experiment On The Aeronomy Of Ice In The Mesosphere Spacecraft: Atmospheric Gravity Waves As Drivers For Longitudinal Variability In Polar Mesospheric Cloud Occurrence, A. Chandran, D. W. Rusch, A. W. Merkel, S. E. Palo, G. E. Thomas, Michael J. Taylor, S. M. Bailey, J. M. Russell Iii
Polar Mesospheric Cloud Structures Observed From The Cloud Imaging And Particle Size Experiment On The Aeronomy Of Ice In The Mesosphere Spacecraft: Atmospheric Gravity Waves As Drivers For Longitudinal Variability In Polar Mesospheric Cloud Occurrence, A. Chandran, D. W. Rusch, A. W. Merkel, S. E. Palo, G. E. Thomas, Michael J. Taylor, S. M. Bailey, J. M. Russell Iii
All Physics Faculty Publications
The cloud imaging and particle size (CIPS) experiment is one of three instruments on board the Aeronomy of Ice in the Mesosphere (AIM) spacecraft that was launched into a 600 km Sun‐synchronous orbit on 25 April 2007. CIPS images have shown distinct wave patterns and structures in polar mesospheric clouds (PMCs), around the summertime mesopause region, which are qualitatively similar to structures seen in noctilucent clouds (NLCs) from ground‐based photographs. The structures in PMC are generally considered to be manifestations of upward propagating atmospheric gravity waves (AGWs). Variability of AGW effects on PMC reported at several lidar sites has led …
On Theconsistency Of Model, Ground-Based And Satellite Observations Of Tidal Signatures: Initial Results From Thecawses Tidal Campaigns, W. E. Ward, J. Oberheide, L. P. Goncharenko, T. Nakamura, P. Hoffmann, W. Singer, L. C. Chang, J. Du, D. Y. Wang, P. Batista, B. Clemesha, A. H. Manson, D. M. Riggin, C. Y. She, T. Tsuda, Tao Yuan
On Theconsistency Of Model, Ground-Based And Satellite Observations Of Tidal Signatures: Initial Results From Thecawses Tidal Campaigns, W. E. Ward, J. Oberheide, L. P. Goncharenko, T. Nakamura, P. Hoffmann, W. Singer, L. C. Chang, J. Du, D. Y. Wang, P. Batista, B. Clemesha, A. H. Manson, D. M. Riggin, C. Y. She, T. Tsuda, Tao Yuan
All Physics Faculty Publications
Comparisons between tidal wind signatures diagnosed from satellite and ground-based observations and a general circulations model for two (September–October 2005, March–April 2007) of the four Climate and Weather of the Sun-Earth System (CAWSES) Global Tidal Campaign observation periods are presented (CAWSES is an international program sponsored by Scientific Committee on Solar-Terrestrial Physics). Specific comparisons are made between model (extended Canadian Middle Atmosphere Model), satellite (Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)), meteor, MF and incoherent scatter radar (ISR), and lidar tidal signatures in the mesosphere and lower thermosphere. The satellite and ground-based signatures are in good agreement and demonstrate for …
Simultaneous Separation And Detection Of Cations And Anions Ion A Microfluidic Device With Suppressed Electroosmotic Flow And A Single Injection Point, B. R. Reschke, J. Schiffbauer, Boyd F. Edwards, A. T. Timperman
Simultaneous Separation And Detection Of Cations And Anions Ion A Microfluidic Device With Suppressed Electroosmotic Flow And A Single Injection Point, B. R. Reschke, J. Schiffbauer, Boyd F. Edwards, A. T. Timperman
All Physics Faculty Publications
A rapid and simultaneous separation of cationic and anionic peptides and proteins in a glass microfluidic device that has been covalently modified with a neutral poly(ethylene glycol) (PEG) coating to minimize protein adsorption is presented. The features of the device allow samples that contain both anions and cations to be introduced from a central flow stream and separated in different channels with different outlets—all in the presence of low electroosmotic flow (EOF) imparted by the PEG coating. The analytes are electrophoretically extracted from a central hydrodynamic stream and electrophoretically separated in two different channels, in which pressure driven flow has …
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, …
Equatorial Ionosphere Bottom-Type Spread-F Observed By Oi 630.0 Nm Airglow Imaging, H. Takahashi, M. A. Abdu, Michael J. Taylor, Pierre-Dominique Pautet, E. R. De Paula, E. A. Kherani, A. F. Medeiros, C. M. Wrasse, I. S. Batista, J. H.A. Sobral, D. Gobbi, D. Arruda, I. Paulino, S. Vadas, D. C. Fritts
Equatorial Ionosphere Bottom-Type Spread-F Observed By Oi 630.0 Nm Airglow Imaging, H. Takahashi, M. A. Abdu, Michael J. Taylor, Pierre-Dominique Pautet, E. R. De Paula, E. A. Kherani, A. F. Medeiros, C. M. Wrasse, I. S. Batista, J. H.A. Sobral, D. Gobbi, D. Arruda, I. Paulino, S. Vadas, D. C. Fritts
All Physics Faculty Publications
Bottom‐type spread F events were observed in the south American equatorial region by a VHF coherent radar and an ionosonde at São Luís (2.5°S, 44.3°W), an ionosonde at Fortaleza (3.9°S, 38.4° W) and an airglow OI 630.0 nm imager at Cariri (7.4°S, 36.5°W) and Brasilia (14.8°S, 47.6°W). In the evening of September 30, 2005, a long duration (∼70 minutes) bottom side scattering layer, confined in a narrow height region, was observed. At the same time all‐sky imager observed sinusoidal intensity depletions in the zonal plane extending more than 1500 km and elongated along the magnetic meridian. No strong spread F …
Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. Hoffman, John R. Dennison
Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. Hoffman, John R. Dennison
All Physics Faculty Publications
The electron emission properties of a material subject to incident radiation flux are key parameters in determining to what equilibrium charge a spacecraft will established under given environmental conditions. However, there is a complex relation between these emission properties and the charge built up in spacecraft insulators. Complex modeling codes have been developed to predict the potential a spacecraft will adopt as a consequence of its interaction with the space plasma. These require correct models of the electron yields as a function of charge to accurately predict the both the charge build up and the equilibrium potential of spacecraft components. …
Approximation Of Range In Materials As A Function Of Incident Electron Energy, Gregory Wilson, John R. Dennison
Approximation Of Range In Materials As A Function Of Incident Electron Energy, Gregory Wilson, John R. Dennison
All Physics Faculty Publications
A simple composite analytic expression has been developed to approximate the electron range in materials. The expression is applicable over more than six orders of magnitude in energy (10 MeV) and range (10-9 m to 10-2 m), with uncertainty of ≤20% for most conducting, semiconducting and insulating materials. This is accomplished by fitting data from two standard NIST databases [ESTAR for the higher energy range and the electron IMFP (inelastic mean free path) for the lower energies]. In turn, these data have been fit with well-established semi-empirical models for range and IMFP that are related to standard materials properties (e.g., …
Understanding Space Weather Customers In Gps-Reliant Industries, Jennifer L. Meehan, G. Fisher, W. Murtagh
Understanding Space Weather Customers In Gps-Reliant Industries, Jennifer L. Meehan, G. Fisher, W. Murtagh
All Physics Faculty Publications
Since the last solar maximum, society has become extremely reliant on the Global Positioning System (GPS), which is often referred to as the “fourth utility” behind electricity, water, and natural gas. As the economy depends more and more on positioning, navigation, and timing, society's vulnerability to space weather continues to increase because space weather can be a significant cause of GPS errors. Critical applications such as railway control, highway traffic management, precision agriculture, emergency response, commercial aviation, and marine navigation all require GPS services. With such widespread and critical usage, industries are becoming more aware of how space weather can …
Space Weather & Gps Reliant Industries, Jennifer L. Meehan, W. Murtagh
Space Weather & Gps Reliant Industries, Jennifer L. Meehan, W. Murtagh
All Physics Faculty Publications
No abstract provided.
Space Weather & Gps Reliant Industries, Jennifer L. Meehan, W. Murtagh
Space Weather & Gps Reliant Industries, Jennifer L. Meehan, W. Murtagh
All Physics Faculty Publications
No abstract provided.
When Are Chiasms Admissible As Evidence?, Boyd F. Edwards, W. F. Edwards
When Are Chiasms Admissible As Evidence?, Boyd F. Edwards, W. F. Edwards
All Physics Faculty Publications
Since John Welch’s discovery of chiasmus in the Book of Mormon in 1967, many critics have attempted to show how chiasmus appears in just about every type of literature, from Dr. Seuss to Strangite scripture. This article discusses the authors’ statistical admissibility tests to verify whether a chiasmus in a work shows strong evidence of intentionality by the original author. Their results indicate that certain passages in the Old Testament and in the Book of Mormon show deliberate chiasmus, while Strangite scripture, the Doctrine and Covenants, nursery rhymes, Dr. Seuss, and other works are not intentionally chiastic.
Does Chiasmus Appear In The Book Of Mormon By Chance?, Boyd F. Edwards, W. F. Edwards
Does Chiasmus Appear In The Book Of Mormon By Chance?, Boyd F. Edwards, W. F. Edwards
All Physics Faculty Publications
Chiasmus is an inverted-parallel literary form that was employed by ancient Hebrew biblical writers, among others. An instance of this form, called a “chiasm,” presents two or more literary elements, and then restates them in reverse order. Short chiasms are not uncommon in literature. In some cases, the authors undoubtedly intended to use that form for literary effect (that is, by design); in other cases, the elements fell into that form without author intent (that is, by chance). In 1969, John W. Welch reported his discovery of many-element chiasms in the Book of Mormon,1 which Joseph Smith testified to …
A Global Climatology Of The Mesospheric Sodium Layerfrom Gomos Data During The 2002-2008 Period, D. F. Fussen, F. Vanhellemont, C. T'Etart, N. Mateshvili, E. Dekemper, N. Loodts, C. Bingen, E. Kyrola, J. Tamminen, V. Sofieva, A. Hauchecorne, F. Dalaudier, J. L. Bertaux, G. Barrot, L. Blanot, O. Fanton D'Andon, T. Fehr, L. Saavedra, Tao Yuan, C. Y. She
A Global Climatology Of The Mesospheric Sodium Layerfrom Gomos Data During The 2002-2008 Period, D. F. Fussen, F. Vanhellemont, C. T'Etart, N. Mateshvili, E. Dekemper, N. Loodts, C. Bingen, E. Kyrola, J. Tamminen, V. Sofieva, A. Hauchecorne, F. Dalaudier, J. L. Bertaux, G. Barrot, L. Blanot, O. Fanton D'Andon, T. Fehr, L. Saavedra, Tao Yuan, C. Y. She
All Physics Faculty Publications
This paper presents a climatology of the mesospheric sodium layer built from the processing of 7 years of GOMOS data. With respect to preliminary results already published for the year 2003, a more careful analysis was applied to the averaging of occultations inside the climatological bins (10° in latitude-1 month). Also, the slant path absorption lines of the Na doublet around 589 nm shows evidence of partial saturation that was responsible for an underestimation of the Na concentration in our previous results. The sodium climatology has been validated with respect to the Fort Collins lidar measurements and, to a lesser …
Observations Of Prolific Transient Luminous Event Production Above A Mesoscale Convective System In Argentina During The Sprite2006 Campaign In Brazil, F. T. São Sabbas, Michael J. Taylor, Pierre-Dominique Pautet, T. Berkey, S. Cummer, R. R. Azambuja, J. P.C. Santiago, J. N. Thomas, O. Pinto Jr., N. N. Solorzano, N. J. Schuch, S. R. Freitas, N. J. Ferreira, J. C. Conforte
Observations Of Prolific Transient Luminous Event Production Above A Mesoscale Convective System In Argentina During The Sprite2006 Campaign In Brazil, F. T. São Sabbas, Michael J. Taylor, Pierre-Dominique Pautet, T. Berkey, S. Cummer, R. R. Azambuja, J. P.C. Santiago, J. N. Thomas, O. Pinto Jr., N. N. Solorzano, N. J. Schuch, S. R. Freitas, N. J. Ferreira, J. C. Conforte
All Physics Faculty Publications
On the night of 22–23 February 2006, 444 transient luminous events (TLEs), 86% sprites, were observed above a prolific mesoscale convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR) cloud top temperatures (Tc) and Tropical Rainfall Measuring Mission (TRMM) radar (PR) and microwave (TMI) data were used to investigate the MCS convective characteristics and their relationship with World Wide Location Network (WWLLN) detected cloud‐to‐ground (CG) lightning and TLE activity. The MCS had a minimum lifetime of 20 hours, 8.5 as a MCS, a maximum extent of ∼430,000 km2, and gusty winds of …
Charge Dynamics In Highly Insulating Space Craft Materials, Alec Sim, John R. Dennison
Charge Dynamics In Highly Insulating Space Craft Materials, Alec Sim, John R. Dennison
All Physics Faculty Publications
We present a preliminary report on the theoretical and experimental study of transport models in highly insulating materials. The report is developed in four sections; first we give background on the nature of the problems in space craft charging, the contributions and connections made by the Utah State material physics group. Second we discuss the density of states to explore the connections between material composition and the microscopic and macroscopic transport equations. Third from Maxwell’s equations we present an overview of the transport equations. Finally we present preliminary results using experimental data on KaptonTM, the transport equations and relevant expressions …
The Effects Of Surface Modification On Spacecraft Charging Parameters, Amberly Evans, John R. Dennison
The Effects Of Surface Modification On Spacecraft Charging Parameters, Amberly Evans, John R. Dennison
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Charging of materials by incident radiation is affected by both environmental and physical conditions. Modifying a material’s physical surface will change its reflection, transmission and absorption of the incident radiation which are integrally related to the accumulation of charge and energy deposition in the material. An optical analysis of the effect of surface modification on spacecraft charging parameters on prototypical Kapton HN and Cu samples is presented. Samples were roughened with abrasive compounds ranging from 0.5 to 10 μm in size, comparable to the range of incident wavelengths. They were also contaminated with thin layers of DC 704 diffusion pump …
Methods To Determine Total Electron-Induced Electron Yields Over Broad Range Ofconductive And Nonconductive Materials, Ryan C. Hoffmann, John R. Dennison
Methods To Determine Total Electron-Induced Electron Yields Over Broad Range Ofconductive And Nonconductive Materials, Ryan C. Hoffmann, John R. Dennison
All Physics Faculty Publications
The electron emission properties of a material subject to incident radiation flux are key parameters in determining to what equilibrium charge a spacecraft will established under given environmental conditions. However, there is a complex relation between these emission properties and the charge built up in spacecraft insulators. Complex modeling codes have been developed to predict the potential a spacecraft will adopt as a consequence of its interaction with the space plasma. These require correct models of the electron yields as a function of charge to accurately predict the both the charge build up and the equilibrium potential of spacecraft components. …
Unified Model Of Charge Transport In Insulating Polymeric Materials, Alec Sim, John R. Dennison
Unified Model Of Charge Transport In Insulating Polymeric Materials, Alec Sim, John R. Dennison
All Physics Faculty Publications
We present a preliminary report on the theoretical and experimental study of transport models in highly insulating materials. The report is developed in four sections; first we give background on the nature of the problems in space craft charging, the contributions and connections made by the Utah State material physics group. Second we discuss the density of states to explore the connections between material composition and the microscopic and macroscopic transport equations. Third from Maxwell’s equations we present an overview of the transport equations. Finally we present preliminary results using experimental data on KaptonTM, the transport equations and …
Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. C. Hoffman, John R. Dennison
Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. C. Hoffman, John R. Dennison
All Physics Faculty Publications
The electron emission properties of a material subject to incident radiation flux are key parameters in determining to what equilibrium charge a spacecraft will established under given environmental conditions. However, there is a complex relation between these emission properties and the charge built up in spacecraft insulators. Complex modeling codes have been developed to predict the potential a spacecraft will adopt as a consequence of its interaction with the space plasma. These require correct models of the electron yields as a function of charge to accurately predict the both the charge build up and the equilibrium potential of spacecraft components. …
Spacecraft Coating-Induced Charging: A Materials And Modeling Study Of Environmental Extreme, Michelle M. Donegan, Jennifer L. Sample, John R. Dennison, R. Hoffman
Spacecraft Coating-Induced Charging: A Materials And Modeling Study Of Environmental Extreme, Michelle M. Donegan, Jennifer L. Sample, John R. Dennison, R. Hoffman
All Physics Faculty Publications
As mankind reaches to explore extreme environments in space, the application of ceramics surface coatings is increasing. The 2005 mission concept for Solar Probe used a unique design to achieve the necessary thermal control for a very close approach to the solar corona, including the use of a highly refractory, electrically insulating ceramic coating over a carbon-carbon composite heat shield. The proposed trajectory takes the spacecraft from a Jovian fly-by to within 4 solar radii of the Sun, spanning 5 orders of magnitude in solar radiation and solar wind plasma density as well as spacecraft temperatures from <100 K to >2000 K. Using …