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Articles 1831 - 1860 of 7341

Full-Text Articles in Physical Sciences and Mathematics

Creating Space Plasma From The Ground, Herbert C. Carlson, Frank T. Djuth, L. D. Zhang Jan 2017

Creating Space Plasma From The Ground, Herbert C. Carlson, Frank T. Djuth, L. D. Zhang

All Physics Faculty Publications

We have performed an experiment to compare as directly as realizable the ionization production rate by HF radio wave energy versus by solar EUV. We take advantage of the commonality that ionization production by both ground-based high-power HF radio waves and by solar EUV is driven by primary and secondary suprathermal electrons near and above ~20 eV. Incoherent scatter radar (ISR)plasma-line amplitudes are used as a measure of suprathermal electron fluxes for ISR wavelengths near those for 430 MHz and are indeed a clean measure of such for those fluxes sufficiently weak to have negligible self-damping. We present data from …

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Effects Of Space Travel On Seed Germination And Viability, Greema Dhiman, Michelle Jung, Andre Nguyen, Shaunda Wenger, Alexander Souvall, Jr Dennison, Takuyuki Sakai, Takahiro Shimizu, Yuta Takahashi, Midori Morikawa, Shusuke Okita, Akihiro Nagata, Toshihiro Kameda Jan 2017

Effects Of Space Travel On Seed Germination And Viability, Greema Dhiman, Michelle Jung, Andre Nguyen, Shaunda Wenger, Alexander Souvall, Jr Dennison, Takuyuki Sakai, Takahiro Shimizu, Yuta Takahashi, Midori Morikawa, Shusuke Okita, Akihiro Nagata, Toshihiro Kameda

Posters

No abstract provided.

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Empirical And Modeling Analyses Of The Circulation Influences On California Precipitation Deficits, Yen-Heng Lin, Lawrence E. Hipps, Shih-Yu (Simon) Wang, Jin-Ho Yoon Jan 2017

Empirical And Modeling Analyses Of The Circulation Influences On California Precipitation Deficits, Yen-Heng Lin, Lawrence E. Hipps, Shih-Yu (Simon) Wang, Jin-Ho Yoon

Plants, Soils, and Climate Faculty Publications

Amplified and persistent ridges in western North America are recurring features associated with drought conditions in California. The recent drought event (2012–2016) lasted through both La Niña and El Niño episodes, suggesting additional climate drivers are important in addition to the commonly perceived El Niño-Southern Oscillation. Diagnostic analyses presented here suggest that, while the Pacific North American (PNA) and North Pacific Oscillation (NPO) do not directly cause drought in California, the relationships between them and with the upper air circulation pattern do modulate the spatial drought pattern. The positive PNA relative circulation leads drier northern California, and (-NPO) relative circulation …

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Assessing The Risk Of Carbon Dioxide Emissions From Blue Carbon Ecosystems, Catherine E. Lovelock, Trisha Brooke Atwood, Jeff Baldock, Carlos M. Duarte, Sharyn Hickey, Paul S. Lavery, Pere Masque, Peter I. Macreadie, Aurora M. Ricart, Oscar Serrano, Andy Steven Jan 2017

Assessing The Risk Of Carbon Dioxide Emissions From Blue Carbon Ecosystems, Catherine E. Lovelock, Trisha Brooke Atwood, Jeff Baldock, Carlos M. Duarte, Sharyn Hickey, Paul S. Lavery, Pere Masque, Peter I. Macreadie, Aurora M. Ricart, Oscar Serrano, Andy Steven

Watershed Sciences Faculty Publications

“Blue carbon” ecosystems, which include tidal marshes, mangrove forests, and seagrass meadows, have large stocks of organic carbon (Corg) in their soils. These carbon stocks are vulnerable to decomposition and – if degraded – can be released to the atmosphere in the form of CO2. We present a framework to help assess the relative risk of CO2 emissions from degraded soils, thereby supporting inclusion of soil Corg into blue carbon projects and establishing a means to prioritize management for their carbon values. Assessing the risk of CO2 emissions after various kinds of disturbances …

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Effect Of Scrape-Off-Layer Current On Reconstructed Tokamak Equilibrium, J. R. King, Scott E. Kruger, Richard J. Groebner, James D. Hanson, J. D. Hebert, Eric D. Held, J. R. Jepson Jan 2017

Effect Of Scrape-Off-Layer Current On Reconstructed Tokamak Equilibrium, J. R. King, Scott E. Kruger, Richard J. Groebner, James D. Hanson, J. D. Hebert, Eric D. Held, J. R. Jepson

All Physics Faculty Publications

Methods are described that extend fields from reconstructed equilibria to include scrape-off-layer current through extrapolated parametrized and experimental fits. The extrapolation includes both the effects of the toroidal-field and pressure gradients which produce scrape-off-layer current after recomputation of the Grad-Shafranov solution. To quantify the degree that inclusion of scrape-off-layer current modifies the equilibrium, the χ-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in χ-squared is found to be minor when scrape-off-layer current is included; however, flux surfaces are shifted by up to cm3 cm. The impact on edge modes of these scrape-off-layer modifications is …

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Hemispherical Grid Retarding Field Analyzer Redesign For Secondary Electron Emission Studies, Gregory Wilson Jan 2017

Hemispherical Grid Retarding Field Analyzer Redesign For Secondary Electron Emission Studies, Gregory Wilson

Conference Proceedings

No abstract provided.

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Dynamic Secondary Electron Emission In Dielectric/Conductor Mixed Coatings, Leandro Olano, Maria E. Davila, A. Jacas, M A. Rodriguez, Jr Dennison Jan 2017

Dynamic Secondary Electron Emission In Dielectric/Conductor Mixed Coatings, Leandro Olano, Maria E. Davila, A. Jacas, M A. Rodriguez, Jr Dennison

Conference Proceedings

No abstract provided.

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Density Of State Models And Temperature Dependence Of Radiation Induced Conductivity, Jodie Corbridge Gillespie, Jr Dennison, Alec M. Sim Jan 2017

Density Of State Models And Temperature Dependence Of Radiation Induced Conductivity, Jodie Corbridge Gillespie, Jr Dennison, Alec M. Sim

Journal Articles

Expressions are developed for radiation induce conductivity (RIC) over an extended temperature range, based on density of states models for highly disordered insulating materials. A general discussion of the DOS of can be given using two simple types of DOS distributions of defect states within the bandgap for disordered materials are considered, one that monotonically decreases within the bandgap and one with a distribution peak within the band gap. Three monotonically decreasing models (exponential, power law, and linear), and two peaked models (Gaussian and delta function) are considered, plus limiting cases with a uniform DOS for each type. Variations using …

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Temporal And Spatial Correlations In Electron-Induced Arcs Of Adjacent Dielectric Islands, Justin Christensen, Jr Dennison, Justin Dekany Jan 2017

Temporal And Spatial Correlations In Electron-Induced Arcs Of Adjacent Dielectric Islands, Justin Christensen, Jr Dennison, Justin Dekany

Journal Articles

This study investigates very short duration (

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Temperature Dependence Of Electrostatic Discharge In Highly Disordered Polymers, Tyler Kippen, Allen Andersen, Jr Dennison Jan 2017

Temperature Dependence Of Electrostatic Discharge In Highly Disordered Polymers, Tyler Kippen, Allen Andersen, Jr Dennison

Posters

No abstract provided.

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Temperature Dependence Of Electrostatic Discharge In Highly Disordered Polymers, Tyler Kippen, Allen Andersen, Jr Dennison Jan 2017

Temperature Dependence Of Electrostatic Discharge In Highly Disordered Polymers, Tyler Kippen, Allen Andersen, Jr Dennison

Posters

No abstract provided.

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Temperature Dependency Of Electrostatic Breakdown In Ldpe And Peek, Tyler Kippen, Allen Andersen, Jr Dennison Jan 2017

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

Posters

No abstract provided.

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Dynamic Secondary Electron Emission In Dielectric/Conductor Mixed Coatings, Leandro Olano, Isabel Montero, Maria E. Davila, Jr Dennison Jan 2017

Dynamic Secondary Electron Emission In Dielectric/Conductor Mixed Coatings, Leandro Olano, Isabel Montero, Maria E. Davila, Jr Dennison

Presentations

No abstract provided.

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Reduction Of Radiation Effects In Polymers Relaxation Of Radiation Effects On The Optical Transmission Of Polymers, Alexandra Hughlett, Tyler Kippen, Jr Dennison Jan 2017

Reduction Of Radiation Effects In Polymers Relaxation Of Radiation Effects On The Optical Transmission Of Polymers, Alexandra Hughlett, Tyler Kippen, Jr Dennison

Presentations

No abstract provided.

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Hemispherical Grid Retarding Field Analyzer Redesign For Secondary Electron Emission Studies, Gregory Wilson Jan 2017

Hemispherical Grid Retarding Field Analyzer Redesign For Secondary Electron Emission Studies, Gregory Wilson

Presentations

No abstract provided.

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Satellite Survivability In Space: A Materials Perspective, Jr Dennison Jan 2017

Satellite Survivability In Space: A Materials Perspective, Jr Dennison

Presentations

No abstract provided.

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Electron Yield Measurements Of High-Yield, Low-Conductivity Dielectric Materials, Justin Christensen Jan 2017

Electron Yield Measurements Of High-Yield, Low-Conductivity Dielectric Materials, Justin Christensen

Senior Theses and Projects

No abstract provided.

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Degradation Effects Of Ionizing Radiation On Spacecraft Components And Biological Samples, Alex Souvall Jan 2017

Degradation Effects Of Ionizing Radiation On Spacecraft Components And Biological Samples, Alex Souvall

Senior Theses and Projects

No abstract provided.

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Uv Degradation Of Polycarbonate, Katie Gamaunt Jan 2017

Uv Degradation Of Polycarbonate, Katie Gamaunt

Senior Theses and Projects

No abstract provided.

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Measuring And Modeling The Conductivity Of Highly Insulating Materials, David King Jan 2017

Measuring And Modeling The Conductivity Of Highly Insulating Materials, David King

Senior Theses and Projects

No abstract provided.

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Payments For Carbon Sequestration To Alleviate Development Pressure In A Rapidly Urbanizing Region, Jordan Smith, Monica A. Dorning, Douglas A. Shoemaker, Andréanne Méley, Lauren Nicole Dupéy, Ross K. Meentemeyer Jan 2017

Payments For Carbon Sequestration To Alleviate Development Pressure In A Rapidly Urbanizing Region, Jordan Smith, Monica A. Dorning, Douglas A. Shoemaker, Andréanne Méley, Lauren Nicole Dupéy, Ross K. Meentemeyer

Environment and Society Faculty Publications

The purpose of this study was to determine individuals’ willingness to enroll in voluntary payments for carbon sequestration programs through the use of a discrete choice experiment delivered to forest owners living in the rapidly urbanizing region surrounding Charlotte, North Carolina. We examined forest owners’ willingness to enroll in payments for carbon sequestration policies under different levels of financial incentives (annual revenue), different contract lengths and different program administrators (e.g., private companies versus a state or federal agency). We also examined the influence forest owners’ sense of place had on their willingness to enroll in hypothetical programs. Our results showed …

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Case Study For Guided Project In Stochastic Hydrology, Meghna Babbar-Sebens Jan 2017

Case Study For Guided Project In Stochastic Hydrology, Meghna Babbar-Sebens

All ECSTATIC Materials

Attached are two guided project activities for hydrology and climate data of Eagle Creek Watershed, Indiana, USA. The zip files have flow and precipitation datasets at daily, monthly, and annual time scales.

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Predator-Prey Coevolution Drives Productivity-Richness Relationships In Planktonic Systems, Zhichao Pu, Michael H. Cortez, Lin Jiang Jan 2017

Predator-Prey Coevolution Drives Productivity-Richness Relationships In Planktonic Systems, Zhichao Pu, Michael H. Cortez, Lin Jiang

Mathematics and Statistics Faculty Publications

The relationship between environmental productivity and species richness often varies among empirical studies, and despite much research, simple explanations for this phenomenon remain elusive. We investigated how phytoplankton and zooplankton coevolution shapes productivity-richness relationships in both phytoplankton and zooplankton, using a simple nutrient-phytoplankton-zooplankton model that incorporates size-dependent metabolic rates summarized from empirical studies. The model allowed comparisons of evolved species richness across productivity levels and at different evolutionary times. Our results show that disruptive selection leads to evolutionary branching of phytoplankton and zooplankton. Both the time required for evolutionary branching and the number of evolved species in phytoplankton and zooplankton …

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Flipped Learning In Synchronously-Delivered, Geographically-Dispersed General Chemistry Classrooms, Michael A. Christiansen, Louis Nadelson, Lianna K. Etchberger, Marilyn M. Cuch, Trish A. Kingsford, Leslie O. Woodward Jan 2017

Flipped Learning In Synchronously-Delivered, Geographically-Dispersed General Chemistry Classrooms, Michael A. Christiansen, Louis Nadelson, Lianna K. Etchberger, Marilyn M. Cuch, Trish A. Kingsford, Leslie O. Woodward

Chemistry and Biochemistry Faculty Publications

In synchronously-delivered, multi-site classrooms, the physical separation between distance students and instructors may create a perceived divide that negatively affects learning. Building on prior experience in flipping organic chemistry in single-site face-to-face (F2F) classes, we decided to extend our approach to multi-site, synchronously-delivered general chemistry courses. Our thought was to narrow the perceived instructor-student divide in distance teaching by using the flexible in-class time that flipping affords to increase the number of positive teacher/distance-student interactions. In this effort, we gradually developed a technique called “bridging questions,” through which the instructor becomes more familiar with student interests and then connects those …

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Perihelion Precession In The General Theory Of Relativity, Charles G. Torre Jan 2017

Perihelion Precession In The General Theory Of Relativity, Charles G. Torre

Tutorials on... in 1 hour or less

This is 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 on the general theory of relativity will derive this result. My analysis aligns with that found in the good old text "Introduction to General Relativity", by Adler, Bazin and Schiffer.

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Greater Sage-Grouse Resource Selection Drives Reproductive Fitness Under A Conifer Removal Strategy, Charles P. Sandford, Michel T. Kohl, Terry A. Messmer, David K. Dahlgren, Avery Cook, Brian R. Wing Jan 2017

Greater Sage-Grouse Resource Selection Drives Reproductive Fitness Under A Conifer Removal Strategy, Charles P. Sandford, Michel T. Kohl, Terry A. Messmer, David K. Dahlgren, Avery Cook, Brian R. Wing

Wildland Resources Faculty Publications

The link between individual variation in resource selection (e.g., functional response) and fitness creates a foundation for understanding wildlife-habitat relationships. Although many anthropogenic activities adversely affect these relationships, it is largely unknown whether projects implemented to benefit wildlife populations actually achieve this outcome. For sagebrush (Artemisia spp.) obligate species such as the greater sage-grouse (Centrocercus urophasianus; sage-grouse), expansion of juniper (Juniperus spp.) and pinyon-pine (Pinus spp.; conifers) woodlands into sagebrush ecosystems has been identified as a conservation threat. This threat is intensified when a sagebrush ecosystem is bounded by naturally unsuitable habitats. As such, federal, state, …

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Development And Testing Of Cool-Season Grass Species, Varieties And Hybrids For Biomass Feedstock Production In Western North America, Steven R. Larson, Calvin H. Pearson, Kevin B. Jensen, Thomas A. Jones, Ivan W. Mott, Matthew Darwin Robbins, Jack E. Staub, Blair L. Waldron Jan 2017

Development And Testing Of Cool-Season Grass Species, Varieties And Hybrids For Biomass Feedstock Production In Western North America, Steven R. Larson, Calvin H. Pearson, Kevin B. Jensen, Thomas A. Jones, Ivan W. Mott, Matthew Darwin Robbins, Jack E. Staub, Blair L. Waldron

Plants, Soils, and Climate Faculty Publications

Breeding of native cool-season grasses has the potential to improve forage production and expand the range of bioenergy feedstocks throughout western North America. Basin wildrye (Leymus cinereus) and creeping wildrye (Leymus triticoides) rank among the tallest and most rhizomatous grasses of this region, respectively. The objectives of this study were to develop interspecific creeping wildrye (CWR) × basin wildrye (BWR) hybrids and evaluate their biomass yield relative to tetraploid ‘Trailhead’, octoploid ‘Magnar’ and interploidy-hybrid ‘Continental’ BWR cultivars in comparison with other perennial grasses across diverse single-harvest dryland range sites and a two-harvest irrigated production system. Two …

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The Optical Trapezoid Model: A Novel Approach To Remote Sensing Of Soil Moisture Applied To Sentinel-2 And Landsat-8 Observations, Morteza Sadeghi, Ebrahim Babaeian, Markus Tuller, Scott B. Jones Jan 2017

The Optical Trapezoid Model: A Novel Approach To Remote Sensing Of Soil Moisture Applied To Sentinel-2 And Landsat-8 Observations, Morteza Sadeghi, Ebrahim Babaeian, Markus Tuller, Scott B. Jones

Plants, Soils, and Climate Faculty Publications

The “trapezoid” or “triangle” model constitutes the most popular approach to remote sensing (RS) of surface soil moisture based on coupled thermal (i.e., land surface temperature) and optical RS observations. The model, hereinafter referred to as Thermal-Optical TRAapezoid Model (TOTRAM), is based on interpretation of the pixel distribution within the land surface temperature - vegetation index (LST-VI) space. TOTRAM suffers from two inherent limitations. It is not applicable to satellites that do not provide thermal data (e.g., Sentinel-2) and it requires parameterization for each individual observation date. To overcome these restrictions we propose a novel OPtical TRApezoid Model (OPTRAM), which …

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Gridded Snow Water Equivalent Reconstruction For Utah Using Forest Inventory And Analysis Tree-Ring Data, Daniel Barandiaran, Shih-Yu (Simon) Wang, R. Justin Derose Jan 2017

Gridded Snow Water Equivalent Reconstruction For Utah Using Forest Inventory And Analysis Tree-Ring Data, Daniel Barandiaran, Shih-Yu (Simon) Wang, R. Justin Derose

Plants, Soils, and Climate Faculty Publications

Snowpack observations in the Intermountain West are sparse and short, making them difficult for use in depicting past variability and extremes. This study presents a reconstruction of April 1 snow water equivalent (SWE) for the period of 1850–1989 using increment cores collected by the U.S. Forest Service, Interior West Forest Inventory and Analysis program (FIA). In the state of Utah, SWE was reconstructed for 38 snow course locations using a combination of standardized tree-ring indices derived from both FIA increment cores and publicly available tree-ring chronologies. These individual reconstructions were then interpolated to a 4-km grid using an objective analysis …

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Why Are We Not Evaluating Multiple Competinghypotheses In Ecology And Evolution?, Gustavo S. Betini, Tal Avgar, John M. Fryxell Jan 2017

Why Are We Not Evaluating Multiple Competinghypotheses In Ecology And Evolution?, Gustavo S. Betini, Tal Avgar, John M. Fryxell

Wildland Resources Faculty Publications

The use of multiple working hypotheses to gain strong inference is widely promoted as a means to enhance the effectiveness of scientific investigation. Only 21 of 100 randomly selected studies from the ecological and evolutionary literature tested more than one hypothesis and only eight tested more than two hypotheses. The surprising rarity of application of multiple working hypotheses suggests that this gap between theory and practice might reflect some fundamental issues. Here, we identify several intellectual and practical barriers that discourage us from using multiple hypotheses in our scientific investigation. While scientists have developed a number of ways to avoid …

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