Physical Sciences and Mathematics Commons^™

Classical Examples Of Bäcklund Transformations (Examples 3.1, 3.2, 5.1), Ian M. Anderson, Mark E. Fels

Research Vignettes

This worksheet contains the detailed calculations for Example 3.1, Example 3.2, and Example 5.1 in the paper Bäcklund Transformations for Darboux Integrable Differential Systems: Examples and Applications.

A Backlund Transformation For The A2 Toda System (Example 3.4), Ian M. Anderson, Mark E. Fels

Research Vignettes

This worksheet amplifies results associated to example 3.4 in "Backlund Transformations for Darboux Integrable Differential Systems: Examples and Applications".

Backlund Transformation For 3 Rt + 1 = 0 (Example 3.4), Ian M. Anderson, Mark E. Fels

Research Vignettes

In this worksheet we give all the calculations for Example 3.4 in "Backlund Transformations for Darboux Integrable Differential Systems: Examples and Applications"

The Role Of Space Materials Research In Spacecraft Charging And Satellite Survivability, Jr Dennison

Presentations

No abstract provided.

An Overview Of The Dynamic Interplay Between The Space Environment & Spacecraft Materials, Jr Dennison

Presentations

No abstract provided.

Daytime Plasma Drifts In The Equatorial Lower Ionosphere, D. Hui, B. G. Fejer

All Physics Faculty Publications

We have used extensive radar measurements from the Jicamarca Observatory during low solar flux periods to study the quiet time variability and altitudinal dependence of equatorial daytime vertical and zonal plasma drifts. The daytime vertical drifts are upward and have largest values during September-October. The day-to-day variability of these drifts does not change with height between 150 and 600 km, but the bimonthly variability is much larger in the F region than below about 200 km. These drifts vary linearly with height generally increasing in the morning and decreasing in the afternoon. The zonal drifts are westward during the day …

Electrically Induced Plasma, Nate Ashby

Physics Capstone Projects

My research project, under the mentorship of research professor Ajay Singh was to prove that the plasma he was creating was lasting longer than the electrical current data indicated. He decided that if the plasma was still there, it would be producing light. So we set out to prove that the light emitted from his plasma lasted longer than the current draw measurements.

Dependence Of Electrostatic Field Strength On Voltage Ramp Rates For Spacecraft Materials, Krysta Moser

Senior Theses and Projects

No abstract provided.

Installation Instructions, Ian M. Anderson, Charles G. Torre

Downloads

DifferentialGeometry and DGApplications are contained in Maple library archives (mla files). The documentation is contained in Maple help files. Unzip the downloaded file (if necessary) to reveal the mla and help files.

To install a package, proceed as follows.

(1) Create or identify a directory (folder) where you will keep the mla file(s) and the help file. This should be a directory of your own, not belonging to Maple (e.g., do not use the Maple "lib" directory). Copy the mla and help files there.

(2) Open Maple, at the prompt type libname. This will display where maple currently looks for …

Pre-Breakdown Arcing As A Proxy For Dc Dielectric Breakdown Testing Of Polymeric Insulators, Jr Dennison, Allen Andersen

Presentations

No abstract provided.

Mixed Weibull Distribution Model Of Dc Dielectric Breakdowns With Dual Defect Modes, Allen Andersen, Jr Dennison

Journal Articles

This work provides physical insight into common statistical models for DC dielectric breakdown field strengths. Voltage step-up tests were performed on low density polyethylene films. The merits of generalizations to widely-used empirical Weibull models are discussed. The cumulative probability distributions of the breakdown fields were fit to standard two- and three-parameter Weibull distributions. Mixed two-parameter Weibull distributions, sometimes used in the literature to model multiple breakdown modes, were found to yield the best fits to the data. In addition, the same data were fit to a physically-motivated dual-defect mean field model incorporating both low- and high-energy defect modes with different …

Mixed Weibull Distribution Model Of Dc Dielectric Breakdowns With Dual Defect Modes, Allen Andersen, Jr Dennison

Presentations

Purpose/Aim

This work proposes an enhanced statistical model for DC dielectric breakdown properties, which incorporates both shallow and deep defect modes. By incorporating these physics-based concepts into a traditionally empirical model, its accuracy and utility can be extended.

Experimental/Modeling methods

Voltage step-up tests were performed for various polymeric films. The distributions of the breakdown fields are fit to standard two- and three-parameter Weibull distributions. These are extended for a dual defect model, with separate mean energies for shallow and deep level traps, using mixed Weibull distributions.

Results/discussion

As shown in Fig 1, such enhanced physics-based statistical models can result in …

A Coordinated Study Of 1 H Mesoscale Gravity Waves Propagating From Logan To Boulder With Crrl Na Doppler Lidars And Temperature Mapper, Xian Lu, Cao Chen, Wentao Huang, John A. Smith, Xinzhao Chu, Tao Yuan, Pierre-Dominique Pautet, Michael J. Taylor, Jie Gong, Chihoko Y. Cullens

All Physics Faculty Publications

We present the first coordinated study using two lidars at two separate locations to characterize a 1 h mesoscale gravity wave event in the mesopause region. The simultaneous observations were made with the Student Training and Atmospheric Research (STAR) Na Doppler lidar at Boulder, CO, and the Utah State University Na Doppler lidar and temperature mapper at Logan, UT, on 27 November 2013. The high precision possessed by the STAR lidar enabled these waves to be detected in vertical wind. The mean wave amplitudes are ~0.44 m/s in vertical wind and ~1% in relative temperature at altitudes of 82–107 km. …

Role Of The Strengthened El Nino Teleconnection In The May 2015 Floods Over The Southern Great Plains, S.-Y. Wang, W.-R. Huang, H.-H. Hsu, R. R. Gillies

Plants, Soils, and Climate Faculty Publications

The climate anomalies leading to the May 2015 floods in Texas and Oklahoma were analyzed in the context of El Niño teleconnection in a warmer climate. A developing El Niño tends to increase late-spring precipitation in the southern Great Plains, and this effect has intensified since 1980. Anthropogenic global warming contributed to the physical processes that caused the persistent precipitation in May 2015: Warming in the tropical Pacific acted to strengthen the teleconnection toward North America, modification of zonal wave 5 circulation that deepened the stationary trough west of Texas, and enhanced Great Plains low-level southerlies increasing moisture supply from …

Cobalt-Centred Boron Molecular Drums With The Highest Coordination Number In The Cob16− Cluster, Ivan A. Popov, Tian Jian, Gary V. Lopez, Alexander I. Boldyrev, Lai-Sheng Wang

Chemistry and Biochemistry Faculty Publications

The electron deficiency and strong bonding capacity of boron have led to a vast variety of molecular structures in chemistry and materials science. Here we report the observation of highly symmetric cobalt-centered boron drum-like structures of CoB16⁻, characterized by photoelectron spectroscopy and ab initio calculations. The photoelectron spectra display a relatively simple spectral pattern, suggesting a high symmetry structure. Two nearly degenerate isomers with D8d(I) and C4v (II) symmetries are found computationally to compete for the global minimum. These drum-like structures consist of two B8 rings sandwiching a cobalt atom, which has the highest …

The 2011 Great Flood In Thailand: Climate Diagnostics And Implications From Climate Change, Parichart Promchote, S. -Y. Simon Wang, Paul G. Johnson

Plants, Soils, and Climate Faculty Publications

Severe flooding occurred in Thailand during the 2011 summer season, which resulted in more than 800 deaths and affected 13.6 million people. The unprecedented nature of this flood in the Chao Phraya River basin (CPRB) was examined and compared with historical flood years. Climate diagnostics were conducted to understand the meteorological conditions and climate forcing that led to the magnitude and duration of this flood. Neither the monsoon rainfall nor the tropical cyclone frequency anomalies alone was sufficient to cause the 2011 flooding event. Instead, a series of abnormal conditions collectively contributed to the intensity of the 2011 flood: anomalously …

A Coordinated Study Of 1-H Mesoscale Gravity Waves Propagating From Logan To Boulder With Crrl Na Doppler Lidars And Temperature Mapper, Xian Liu, Cao Chen, Wentao Huang, John A. Smith, Xinzhao Chu, Tao Yuan, Pierre-Dominique Pautet, Michael J. Taylor, Jie Gong, Chihoko Y. Cullens

Publications

We present the first coordinated study using two lidars at two separate locations to characterize a 1 h mesoscale gravity wave event in the mesopause region. The simultaneous observations were made with the Student Training and Atmospheric Research (STAR) Na Doppler lidar at Boulder, CO, and the Utah State University Na Doppler lidar and temperature mapper at Logan, UT, on 27 November 2013. The high precision possessed by the STAR lidar enabled these waves to be detected in vertical wind. The mean wave amplitudes are ~0.44 m/s in vertical wind and ~1% in relative temperature at altitudes of 82–107 km. …

Multi-Scale Environmental Filters And Niche Partitioning Govern The Distributions Of Riparian Vegetation Guilds, Nate Hough-Snee, Brian G. Laub, David M. Merritt, Arin Lexine Long, Lloyd L. Nackley, Brett B. Roper, Joseph Michael Wheaton

Watershed Sciences Faculty Publications

Across landscapes, riparian plant communities assemble under varying levels of disturbance, environmental stress, and resource availability, leading to the development of distinct riparian life-history guilds over evolutionary timescales. Identifying the environmental filters that exert selective pressures on specific riparian vegetation guilds is a critical step in setting baseline expectations for how riparian vegetation may respond to environmental conditions anticipated under future global change scenarios. In this study, we ask: (1) What riparian plant guilds exist across the interior Columbia and upper Missouri River basins? (2) What environmental filters shape riparian guild distributions? (3) How does resource partitioning among guilds influence …

Density Of State Models Of Steady-State Temperature Dependent Radiation Induced Conductivity, Jodie Corbridge Gillespie, Jr Dennison

Posters

Radiation induced conductivity (RIC) occurs when incident radiation deposits energy and excites electrons into the conduction band of insulators. The magnitude of the enhanced conductivity is dependent on a number of factors including temperature and the spatial- and energy-dependence and occupation of the material’s distribution of localized trap states within the band gap—or density of states (DOS). Expressions are developed for steady-state RIC over an extended temperature range, based on DOS models for highly disordered insulating materials. A general discussion of the DOS of disordered materials can be given using two simple distributions: one that monotonically decreases below the band …

Properties Of Spacecraft Materials Exposed To Ionizing Radiation, Alex Souvall, Gregory Wilson, Katie Gamaunt, Ben Russon, Heather Tippets, Jr Dennison

Posters

The effects of ionizing radiation damage on the various properties of spacecraft materials resulting from exposure in the Space Survivability Testing chamber (SST) are being studied with both ex situ and in situ tests. The SST is a ground based test facility designed to mimic low earth orbit (LEO), and geosynchronous orbit to test potential environmental-induced modifications to small satellites , and materials. Tests described here expose spacecraft materials to a Sr⁹⁰ ionizing beta radiation source at room temperature and in high vacuum. Ex situ optical transmission/reflectivity measurements glass samples will monitor optical darkening. Properties of polymeric samples will …

The Space Survivability Test Chamber, Katie Gamaunt, Heather Tippets, Alex Souvall, Ben Russon, Jr Dennison

Posters

The Space Survivability Test chamber is a new ground-based research instrument being used for accelerated testing of environment-induced modifications of diverse samples. The chamber simulates space environment conditions, including neutral gas atmospheres and vacuum (<10^-5 Pa) environments, temperature (~100 K to >450 K), ionizing radiation, electron fluxes (<10 eV to ~2½ MeV), and vacuum ultraviolet through mid-infrared photon fluxes. This versatile test chamber is well-suited for cost-effective testing of complete systems up to the size (< 20 cm dia.) of a 1U CubeSat, smaller components or electronics, and individual material samples. Multiple in-flux or in-situ space survivability and radiation exposure tests can be performed simultaneously, as well as extensive before and after ex-situ tests. Currently the chamber is performing a series of radiation experiments using a Sr⁹⁰ beta radiation source which approximately mimics the geostationary high energy electron spectra at ~4-10X accelerated …

Predictive Formula For Electron Range Over A Large Span Of Energies, Anne C. Starley, Gregory Wilson, Lisa Montierth Phillipps, Jr Dennison

Posters

A model has been developed to predict the approximate penetration depth into diverse classes of materials for a broad range of energetic incident electrons (<10 eV to >10 MeV, with better than 20% accuracy). The penetration depth—or range—of a material describes the maximum distance electrons can travel through a material, before losing all of its incident kinetic energy. This model leads to a predictive formula that estimates the penetration depth for materials without the need for supporting data, but rather using only basic material properties and a single fitting parameter (Nv, described as the effective number of valence electrons). Nv …

Dependence Of Electrostatic Field Strength On Voltage Ramp Rates For Spacecraft Material, Krysta Moser, Allen Andersen, Jr Dennison

Posters

Previous tests done by the USU Materials Physics Group (MPG) using our electrostatic discharge (ESD) custom vacuum chamber have found that, for the polymeric materials polyimide and low density polyethylene (LDPE), the electrostatic field strength at breakdown depends on the voltage ramp rate applied across the materials. At ramp rates an order of magnitude lower than the maximum recommended rate of 500 V/s, the breakdown electrostatic field strength was also found to be significantly lower. The data from these tests were compared to a microscopic mean field theory for dielectric breakdown in highly disordered insulating materials. We present new ramp …

Measurement Of Effects Of Long Term Ionizing Radiation On High Efficiency Solar Arrays, Ben Russon, Heather Tippets, Gregory Wilson, Katie Gamaunt, Alex Souvall, Jr Dennison

Posters

Degradation of power output efficiency for high-efficiency multilayer solar arrays due to ionizing radiation is measured using the Space Survivability Test chamber. Exposure to ionizing radiation disrupts the crystalline structure and can reduce solar array power output to the point that it no longer provides adequate output capacity. This can be a significant concern, particularly in the harsh environment of space where radiation dose rate is significantly higher and replacing components is often impossible. Ionizing radiation is simulated in a controlled environment to allow measurement and characterization of the power output of solar arrays, using a 100 mCi encapsulated Sr90 …

Comparing Experimental Apples And Oranges With Quantile-Quantile Plots, Allen Andersen, Jr Dennison

Presentations

An important question often encountered in experimental physics is, are two observables related or not? Quantile-quantile (q-q) analysis compares the cumulative distributions of two observations (or one set of observations and a theoretical curve) in a way that is both visually apparent and statistically quantifiable. If the two observables follow the same distribution, the q-q plot will be linear; if they are identical the plot will have unity slope. Deviations from a linear q-q plot indicate that the two observables do not follow the same distribution. We show that the q-q analysis method is applicable to a wide range of …

Enhanced Electron Yield Measurements Of Extremely Low-Conductivity High Yield Dielectrics, Justin Christensen, Jr Dennison

Presentations

An important question often encountered in experimental physics is, are two observables related or not? Quantile-quantile (q-q) analysis compares the cumulative distributions of two observations (or one set of observations and a theoretical curve) in a way that is both visually apparent and statistically quantifiable. If the two observables follow the same distribution, the q-q plot will be linear; if they are identical the plot will have unity slope. Deviations from a linear q-q plot indicate that the two observables do not follow the same distribution. We show that the q-q analysis method is applicable to a wide range of …

Using Life History Trade-Offs To Understand Core-Transient Structuring Of A Small Mammal Community, Sarah R. Supp, David N. Koons, S.K. Morgan Ernest

Wildland Resources Faculty Publications

An emerging conceptual framework suggests that communities are composed of two main groups of species through time: core species that are temporally persistent, and transient species that are temporally intermittent. Core and transient species have been shown to differ in spatiotemporal turnover, diversity patterns, and importantly, survival strategies targeted at local versus regional habitat use. While the core-transient framework has typically been a site-specific designation for species, we suggest that if core and transient species have local versus regional survival strategies across sites, and consistently differ in population-level spatial structure and gene flow, they may also typically exhibit different life-history …

Momentum Flux Estimates Accompanying Multiscale Gravity Waves Over Mount Cook, New Zealand, On 13 July 2014 During The Deepwave Campaign, K. Bossert, D. C. Fritts, B. P. Williams, Michael J. Taylor, B. Kaifler, A. Dornbrack, I. M. Reid, D. J. Murphy, A. J. Spargo, A. D. Mackinnon, Pierre-Dominique Pautet

All Physics Faculty Publications

Observations performed with a Rayleigh lidar and an Advanced Mesosphere Temperature Mapper aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V research aircraft on 13 July 2014 during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) measurement program revealed a large-amplitude, multiscale gravity wave (GW) environment extending from ~20 to 90 km on flight tracks over Mount Cook, New Zealand. Data from four successive flight tracks are employed here to assess the characteristics and variability of the larger- and smaller-scale GWs, including their spatial scales, amplitudes, phase speeds, and momentum fluxes. On each flight, a large-scale mountain wave (MW) …

Interactions Between Thiourea And Imines. Prelude To Catalysis, Vincent De Paul Nzuwah-Nziko, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The interaction between thiourea and a series of imines was examined via high-level ab initio calculations. For each imine, there is a set of stable complexes that represent minima on the potential energy surface. One type is characterized by a pair of symmetric NH···N hydrogen bonds (HBs), with both NH groups of thiourea approaching the imine N from above and below its molecular plane. Another geometry category combines a linear NH···N with a CH···S HB. A third, which is less stable, has the S approaching the imine’s CH2 group, and a stacking arrangement is present in the fourth. Interaction energies …

Momentum Flux Estimates Accompanying Multi-Scale Gravity Waves Over Mt. Cook, New Zealand On 13 July 2014 During The Deepwave Campaign, Katrina Bossert, David C. Fritts, Pierre-Dominique Pautet, Bifford P. Williams, Michael J. Taylor, Bernd Kaifler, Andrea Dornbrack, Iain M. Reid, Damian J. Murphy, Andrew J. Spargo, Andrew D. Mackinnon

Publications

Observations performed with a Rayleigh lidar and an Advanced Mesosphere Temperature Mapper aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V research aircraft on 13 July 2014 during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) measurement program revealed a large-amplitude, multiscale gravity wave (GW) environment extending from ~20 to 90 km on flight tracks over Mount Cook, New Zealand. Data from four successive flight tracks are employed here to assess the characteristics and variability of the larger- and smaller-scale GWs, including their spatial scales, amplitudes, phase speeds, and momentum fluxes. On each flight, a large-scale mountain wave (MW) …