Physical Sciences and Mathematics Commons^™

Patterns In Greater Sage-Grouse Population Dynamics Correspond With Public Grazing Records At Broad Scales, Adrian P. Monroe, Cameron L. Aldridge, Timothy J. Assal, Kari E. Veblen, David A. Pyke, Michael L. Casazza

Wildland Resources Faculty Publications

Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004-2014, we modeled population trends in response to grazing level (represented by a relative grazing index) …

Model For Charge Injection With Electron Beams Into Highly Disordered Insulating Materials, Jr Dennison

Presentations

The Walden-Wintle model for charge injection and transport through highly disordered insulating materials has been extended to include charge injection with a charged particle beam. The original model is applicable to charge injection into a dielectric material from a pair of electrodes in a parallel-plate geometry. It provides a versatile approach to predict the time-dependent current at a rear grounded electrode and the incident surface voltage, as the injection current density evolves over time with the development of a space charge barrier near the injection electrode. The Walden-Wintle model has been applied to many standard cases including Fowler-Nordheim injection, Schottky …

A New Physical Model For Dc Partial Discharge In Polymeric Insulators, Allen Andersen, Jr Dennison

Presentations

The physics of DC partial discharge (DCPD) continues to pose a challenge to researchers. We present a new physically-motivated model of DCPD in amorphous polymers based on our dual-defect model of dielectric breakdown. The dual-defect model is an extension of standard static mean field theories, such as the Crine model, that describe avalanche breakdown of charge carriers trapped on uniformly distributed defect sites. It assumes the presence of both high-energy chemical defects and low-energy thermally-recoverable physical defects. We present our measurements of breakdown and DCPD for several common polymeric materials in the context of this model. Improved understanding of DCPD …

Wf-2307 Feasibility Of Integrating Uas Multi-Spectral And Thermal-Infrared Data At Very Fine Pixel Resolutions With The Two-Source (Tseb) And Other Energy Balance Models, Mac Mckee

Funded Research Records

No abstract provided.

Novel Physical Model For Dc Partial Discharge In Polymeric Insulators, Allen Andersen, Jr Dennison

Presentations

No abstract provided.

Model For Charge Injection With Electron Beams Into Highly Disordered Insulating Materials, Jr Dennison

Presentations

No abstract provided.

Comparison Of Halide Receptors Based On H, Halogen, Chalogen, Pnicogen, And Tetrel Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A series of halide receptors are constructed and the geometries and energetics of their binding to F-, Cl-, and Br- assessed by quantum calculations. The dicationic receptors are based on a pair of imidazolium units, connected via a benzene spacer. The imidazoliums each donate a proton to a halide in a pair of H-bonds. Replacement of the two bonding protons by Br leads to binding via a pair of halogen bonds. Likewise, chalcogen, pnicogen, and tetrel bonds occur when the protons are replaced, respectively, by Se, As, and Ge. Regardless of the binding group considered, F- is bound much more …

Climate Drives Fire Synchrony But Local Factors Control Fire Regime Change In Northern Mexico, Larissa L. Yocom Kent, Peter Z. Fule, J. Brown, E. Cerano, E. Cornejo-Oviedo, C. Cortés Montaño, S. A. Drury, D. A. Falk, J. Meunier, H. M. Poulos, C. N. Skinner, S. L. Stephens, J. Villanueva-Diaz

Wildland Resources Faculty Publications

The occurrence of wildfire is influenced by a suite of factors ranging from “top-down” influences (e.g., climate) to “bottom-up” localized influences (e.g., ignitions, fuels, and land use). We carried out the first broad-scale assessment of wildland fire patterns in northern Mexico to assess the relative influence of top-down and bottom-up drivers of fire in a region where frequent fire regimes continued well into the 20th century. Using a network of 67 sites, we assessed (1) fire synchrony and the scales at which synchrony is evident, (2) climate drivers of fire, and (3) asynchrony in fire regime changes. We found high …

The Magnetic Storms Of 3_4 August 2010 And 5_6 August 2011: 1. Ground- And Space-Based Observations, Cesar E. Valladares, J. V. Eccles, S. Basu, Robert W. Schunk, R. Sheehan, R. Pradipta, J. M. Ruohoniemi

All Physics Faculty Publications

We have used total electron content (TEC) values from low, middle, and high latitudes recorded over the American continent and density and ion temperature measured in situ by the DMSP-F15 and F17 satellites during the geomagnetic storms of 3_4 August 2010 and 5_6 August 2011 to study the formation and dynamics of plasma density enhancements that developed during these two storms. Common to both storms are the timing of the main phase that extends between 20 and 24 UT and their seasonality with both storms occurring near the end of the Northern Hemisphere summer solstice. During both storms, TEC data …

Determining Annual Cryosphere Storage Contributions To Stream Flow Using Historical Hydrometric Records, Janice Brahney, Brian Menounos, Xiaohua Wei, Paul Jefferson Curtis

Watershed Sciences Faculty Publications

Alpine glaciers and perennial snow fields are important hydrologic elements in many mountain environments providing runoff during the late summer and during periods of drought. Because relatively long records of glacier mass–balance data are absent from many glacierized catchments, it remains unclear to what extent shrinking perennial snow and glaciers have affected runoff trends from these watersheds. Here, we employ a hydrograph separation technique that uses a double mass curve in an attempt to isolate changes in runoff due to glacier retreat and disappearance of perennial snow. The method is tested using hydrometric data from 20 glacierized and 16 nonglacierized …

Temperature Dependency Of Electrostatic Breakdown In Ldpe And Peek, Tyler Kippen, Allen Andersen, Jr Dennison

Posters

Electrostatic breakdown is a leading cause of many of the anomalies and failures attributed to spacecraft interactions with the space environment. It is therefore critical to understand how the electrostatic field strength varies due to changing environmental conditions, including temperature and radiation dose. Standard step-up to electrostatic discharge (ESD) tests were performed on two polymers, low density polyethylene (LDPE) and polyetheretherketone (PEEK). Tests were done at room temperature and at other temperatures ranging from ~130 K to ~350 K. Preliminary analysis found that samples tested at a higher temperature had lower average breakdown field strength and a narrower distribution of …

Satellite Survivability In A Harsh Space Environment: A Materials Perspective, Jr Dennison

Presentations

No abstract provided.

Using Quantile-Quantile Plots To Compare Experimental Apples And Oranges In Physics Labs, Allen Andersen, Jr Dennison

Presentations

No abstract provided.

Evidence For A Climate-Driven Hydrologic Regime Shift In The Canadian Columbia Basin, Janice Brahney, Frank Weber, Vanessa Foord, John Janmaat, Paul Jefferson Curtis

Watershed Sciences Faculty Publications

Water resources from the Columbia River Basin are intensely used for domestic, agricultural, industrial and hydroelectric generation needs. Water availability in the Pacific Northwest is influenced by several ocean–atmosphere modes of climate variability that occur in the Pacific Ocean. Climate change has the potential to alter these relationships and influence both the volume and timing of streamflow in the snowmelt-dominated tributaries to the Columbia River. Here, the historical influences of climate variability and recent climate warming on the volume and timing of streamflow for 40 tributary streams in the Columbia River Basin of Canada were evaluated. Regional relationships were found …

Analytic Approximation Of Invasion Wave Amplitude Predicts Severity Of Insect Outbreaks, Antje R. H. Graul, James A. Powell

Mathematics and Statistics Faculty Publications

Outbreaks of phytophagous forest insects are largely driven by host demographics and spatial effects of dispersal. We develop a structured integrodifference equation (IDE) outbreak model that tracks the demographics of sedentary hosts under insect infestation pressure. The model is appropriate for a spectrum of pests attacking the later age classes of long-lived hosts, including mountain pine beetle (MPB), spruce budworm, and spruce beetle, which, among them are responsible for more forest damage than fire. The model generates a train of periodic waves of infestation. We approximate the IDE with a partial differential equation and search for traveling wave solutions. The …

Rapid Surface-Water Volume Estimations In Beaver Ponds, Daniel J. Karran, Cherie J. Westbrook, Joseph Michael Wheaton, Carol A. Johnston, Angela Bedard-Haughn

Watershed Sciences Faculty Publications

Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range …

A Variant Of Clark's Theorem And Its Applications For Nonsmooth Functionals Without The Palais-Smale Condition, Shaowei Chen, Zhaoli Liu, Zhi-Qiang Wang

Mathematics and Statistics Faculty Publications

By introducing a new notion of the genus with respect to the weak topology in Banach spaces, we prove a variant of Clark's theorem for nonsmooth functionals without the Palais-Smale condition. In this new theorem, the Palais-Smale condition is replaced by a weaker assumption, and a sequence of critical points converging weakly to zero with nonpositive energy is obtained. As applications, we obtain infinitely many solutions for a quasi-linear elliptic equation which is very degenerate and lacks strict convexity, and we also prove the existence of infinitely many homoclinic orbits for a second-order Hamiltonian system for which the functional is …

Separating Overlapped Intervals On A Line, Shimin Li, Haitao Wang

Computer Science Faculty and Staff Publications

Given n intervals on a line ℓ, we consider the problem of moving these intervals on ℓ such that no two intervals overlap and the maximum moving distance of the intervals is minimized. The difficulty for solving the problem lies in determining the order of the intervals in an optimal solution. By interesting observations, we show that it is sufficient to consider at most n "candidate" lists of ordered intervals. Further, although explicitly maintaining these lists takes Ω(n²) time and space, by more observations and a pruning technique, we present an algorithm that can compute an optimal …

Wildfire In Utah: The Physical And Economic Consequences Of Wildfire, Paul Mark Jakus, Man-Keun Kim, Randy S. Martin, Ian Hammond, Edd Hammill, Nancy O. Mesner, Jacob Stout

Watershed Sciences Faculty Publications

PRELUDE

On June 26, 2012 a lightning strike ignited a wildfire in the Manti-La Sal National Forest of central Utah’s Carbon and Emery counties (Figure P.1). By the time the Seeley wildfire was contained three weeks later, some 48,000 acres of federal, state, and private land had been burned and $8.7 million in suppression costs expended (Styler 2012). According to the Monitoring Trends in Burn Severity (MTBS.gov) project, nearly one-third of the acreage was severely burned, damaging vegetation and soils for years to come. Severe burns vastly increase the erosion potential of burnt landscapes, and the steep lands of Huntington …

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

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 …

Large-Scale Gravity Wave Perturbations In The Mesopause Region Above Northern Hemisphere Midlatitudes During Autumnal Equinox: A Joint Study By The Usu Na Lidar And Whole Atmosphere Community Climate Model, Xuguang Cai, Tao Yuan, Han-Li Liu

All Physics Faculty Publications

To investigate gravity wave (GW) perturbations in the midlatitude mesopause region during boreal equinox, 433h of continuous Na lidar full diurnal cycle temperature measurements in September between 2011 and 2015 are utilized to derive the monthly profiles of GW-induced temperature variance, T′^₂, and the potential energy density (PED). Operating at Utah State University (42°N, 112°W), these lidar measurements reveal severe GW dissipation near 90km, where both parameters drop to their minima (∼ 20K² and ∼50m²s⁻², respectively). The study also shows that GWs with periods of 3–5h dominate the midlatitude mesopause region during …

Interactions Between Uniformly Magnetized Spheres, Boyd F. Edwards, D. Mark Riffe, Jeong-Young Ji, William A. Booth

All Physics Faculty Publications

We use simple symmetry arguments suitable for undergraduate students to demonstrate that the magnetic energy, forces, and torques between two uniformly magnetized spheres are identical to those between two point magnetic dipoles. These arguments exploit the equivalence of the field outside of a uniformly magnetized sphere with that of a point magnetic dipole, and pertain to spheres of arbitrary sizes, positions, and magnetizations. The point dipole/sphere equivalence for magnetic interactions may be useful in teaching and research, where dipolar approximations for uniformly magnetized spheres can now be considered to be exact. The work was originally motivated by interest in the …

Comparison Of Tetrel Bonds In Neutral And Protonated Complexes Of Pyridinetf3 And Furantf3 (T = C, Si, And Ge) With Nh3, Mingxiu Liu, Qing-Zhong Li, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Ab initio calculations have been performed for the complexes H+–PyTX3⋯NH3 and H+–furanTF3⋯NH3 (T = C, Si, and Ge; X = F and Cl) with focus on geometries, energies, orbital interactions, and electron densities to study the influence of protonation on the strength of tetrel bonding. The primary interaction mode between α/β-furanCF3/p-PyCF3 and NH3 changes from an F⋯H hydrogen bond to a C⋯N tetrel bond as a result of protonation. Importantly, the protonation has a prominent enhancing effect on the strength of tetrel bonding with an increase in binding energy from 14 to 30 kcal mol−1. The tetrel bonding becomes stronger …

Daphnia Inhibits The Emergence Of Spatial Pattern In A Simple Consumer-Resource System, Gustavo S. Betini, Tal Avgar, Kevin S. Mccann, John M. Fryxell

Wildland Resources Faculty Publications

Spatial self-organization can occur in many ecosystems with important effects on food web dynamics and the maintenance of biodiversity. The consumer-resource interaction is known to generate spatial patterning, but only a few empirical studies have investigated the effect of the consumer on resource distribution. Here we report results from a large aquatic mesocosm experiment used to investigate the effect of the consumer Daphnia magna on the distribution of its resource, the green algae Chlorella vulgaris. We maintained large tanks with capacity for 26 ,000 L with either algae or both algae and Daphnia in different temperature conditions. We found that …

Numerical Modeling Of A Multiscale Gravity Wave Event And Its Airglow Signatures Over Mount Cook, New Zealand, During The Deepwave Campaign, C. J. Heale, K. Bossert, J. B. Snively, D. C. Fritts, Pierre-Dominique Pautet, Michael J. Taylor

All Physics Faculty Publications

A 2-D nonlinear compressible model is used to simulate a large-amplitude, multiscale mountain wave event over Mount Cook, NZ, observed as part of the Deep Propagating Gravity Wave Experiment (DEEPWAVE) campaign and to investigate its observable signatures in the hydroxyl (OH) layer. The campaign observed the presence of a _x=200ækm mountain wave as part of the 22nd research flight with amplitudes of >20æK in the upper stratosphere that decayed rapidly at airglow heights. Advanced Mesospheric Temperature Mapper (AMTM) showed the presence of small-scale (25_28ækm) waves within the warm phase of the large mountain wave. The simulation results show rapid breaking …

How The Space Environment Affects Seed Germination And Growth, Alexander Souvall, Gareema Dhiman, Andre Nguyen, Michelle Jung, Astrid Ji, Takayuki Sakai, Takahiro Shimizu, Midori Morikawa, Shusuke Okita, Akihiro Nagata, Shaunda Wenger, Toshihiro Kameda, Jr Dennison

Posters

Understanding observed space environment effects on biological organisms such seeds are important in design of long duration space missions, such as to those planned for Mars, where appropriate storage and growth of food resources is essential. Evaluation of the effects of the real and simulated space environment on seed germination and growth in space is the purpose of this research. Preliminary tests of germination rate and growth of radish seeds in a controlled environment have identified statistically significant differences between control samples and seeds flown for 30 days in low earth orbit on the Bion M-1 launch capsule Russian research …

Microcontroller And Memory Card Survivability In Space Conditions, Windy Olsen

Senior Theses and Projects

No abstract provided.

Rainich Conditions In (2 + 1)- Dimensional Gravity, D. S. Krongos, Charles G. Torre

All Physics Faculty Publications

In (3 + 1) spacetime dimensions, the Rainich conditions are a set of equations expressed solely in terms of the metric tensor which are equivalent to the Einstein- Maxwell equations for non-null electromagnetic fields. Here we provide the analogous conditions for (2 + 1)-dimensional gravity coupled to electromagnetism. Both the non-null and null cases are treated. The construction of these conditions is based upon reducing the problem to that of gravity coupled to a scalar field, which we have treated elsewhere. These conditions can be easily extended to other theories of (2 + 1)-dimensional gravity. For example, we apply the …

User Guide For Luminescence Sampling In Archaeological And Geological Context, Michelle C. Summa-Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon A. Mahan

Geosciences Faculty Publications

Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material …