Physical Sciences and Mathematics Commons^™

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

Presentations

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 …

Magnetic Meridional Winds In The Thermosphere Obtained From Global Assimilation Of Ionospheric Measurements (Gaim) Model, Levan Lomidze, Ludger Scherliess, Robert W. Schunk

All Physics Faculty Publications

Thermospheric neutral winds play an important part in the dynamics of ionospheric plasma and represent one of the key inputs for ionospheric physics-based models. Yet wind measurements are scarce and generally lack global coverage and continuity. To help mitigate this shortcoming, a data assimilation model was used to estimate neutral winds in the low- and middle-latitude thermosphere. Seasonal global maps of NmF2 andhmF2 were generated from Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation measurements for geomagnetically quiet and low solar flux conditions. The maps were assimilated into the Utah State University Global Assimilation of …

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

Journal Articles

Pre-breakdown arcing is proposed as a key indicator of DC breakdown properties of polymeric dielectric materials. Voltage step-up tests were performed for films of low-density polyethylene (LDPE) at ramp rates significantly lower than is common in most studies, allowing for the observation of both breakdown and transient pre-breakdown current spikes. The distributions of the breakdowns versus applied field were compared with the more frequent pre-breakdown arcs. A strong correlation was observed for LDPE between the distribution of breakdowns in step-up tests and the distribution of pre-breakdown arcing. Pre-breakdown arcing distributions are much easier to obtain than breakdown distributions and may …

Mountain Pine Beetles Use Volatile Cues To Locate Host Limber Pine And Avoid Non-Host Great Basin Bristlecone Pine, Curtis A. Gray, Justin B. Runyon, Michael J. Jenkins, Andrew D. Giunta

Wildland Resources Faculty Publications

The tree-killing mountain pine beetle (Dendroctonus ponderosae Hopkins) is an important disturbance agent of western North American forests and recent outbreaks have affected tens of millions of hectares of trees. Most western North American pines (Pinus spp.) are hosts and are successfully attacked by mountain pine beetles whereas a handful of pine species are not suitable hosts and are rarely attacked. How pioneering females locate host trees is not well understood, with prevailing theory involving random landings and/or visual cues. Here we show that female mountain pine beetles orient toward volatile organic compounds (VOCs) from host limber pine (Pinus flexilis …

Bear Lake Limnology & Nutrient Limnology, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

No abstract provided.

Added Value From 576 Years Of Tree-Ring Records In The Prediction Of The Great Salt Lake Level, Robert R. Gillies, Oi-Yu Chung, Shih-Yu (Simon) Wang, R. Justin Derose, Yan Sun

Wasatch Dendroclimatology Research

Predicting lake level fluctuations of the Great Salt Lake (GSL) in Utah – the largest terminal salt-water lake in the Western Hemisphere – is critical from many perspectives. The GSL integrates both climate and hydrological variations within the region and is particularly sensitive to low-frequency climate cycles. Since most hydroclimate variable records cover less than a century, forecasting the predominant yet under-represented decadal variability of the GSL level with such relatively short instrumental records poses a challenge. To overcome data limitations, this study assesses two options: (1) developing a model using the observational GSL elevation record of 137 years to …

Dissection Of The Factors Affecting Formation Of A Ch∙∙∙O H-Bond. A Case Study, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations are used to examine how various constituent components of a large molecule contribute to the formation of an internal CH∙∙∙O H-bond. Such a bond is present in the interaction between two amide units, connected together by a series of functional groups. Each group is removed one at a time, so as to monitor the effect of each upon the H-bond, and thereby learn the bare essentials that are necessary for its formation, as well as how its presence affects the overall molecular structure. Also studied is the perturbation caused by change in the length of the aliphatic chain …

Characterizing Demographicparameters Across Environmental Gradients: A Case Study With Ontario Moose, Garrett M. Street, Tal Avgar, Arthur R. Rodgers, John M. Fryxell

Wildland Resources Faculty Publications

Population-level demographic characteristics as estimated by standard logistic growth models (i.e., carrying capacity and intrinsic growth rate) should vary with changes in habitat quality and availability of resources. However, few published studies have tested this hypothesis by comparing population growth rates across broad bioclimatic gradients, and fewer still the carrying capacities of those populations. We used time series data on moose (Alces alces) population densities based on aerial census and hunter harvest data for 34 management units across Ontario to estimate local carrying capacities and intrinsic growth rates. These population parameters were then regressed against associated habitat covariates for each …

Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff

Watershed Sciences Faculty Publications

Anthropogenic activities have significantly altered atmospheric chemistry and changed the global mobility of key macronutrients. Here we show that contemporary global patterns in nitrogen (N) and phosphorus (P) emissions drive large hemispheric variation in precipitation chemistry. These global patterns of nutrient emission and deposition (N:P) are in turn closely reflected in the water chemistry of naturally oligotrophic lakes (r2 = 0.81, p < 0.0001). Observed increases in anthropogenic N deposition play a role in nutrient concentrations (r2 = 0.20, p < 0.05); however, atmospheric deposition of P appears to be major contributor to this pattern (r2 = 0.65, p < 0.0001). Atmospheric simulations indicate a global increase in P deposition by 1.4 times the preindustrial rate largely due to increased dust and biomass burning emissions. Although changes in the mass flux of global P deposition are smaller than for N, the impacts on primary productivity may be greater because, on average, one unit of increased P deposition has 16 times the influence of one unit of N deposition. These stoichiometric considerations, combined with the evidence presented here, suggest that increases in P deposition may be a major driver of alpine Lake trophic status, particularly in the Southern Hemisphere. These results underscore the need for the broader scientific community to consider the impact of atmospheric phosphorus deposition on the water quality of naturally oligotrophic lakes.

Small Satellite Verification And Assessment Test Facility With Space Environments Effects Ground-Testing Capabilities, Eric Stromberg, Crystal Frazier, Lisa Montierth Phillipps, Alex Souvall, Jr Dennison, James S. Dyer

Presentations

The Utah State University Space Dynamics Laboratory (SDL) and Materials Physics Group (MPG) have developed an extensive versatile and cost-effective pre-launch test capability for verification and assessment of small satellites, system components, and spacecraft materials. The facilities can perform environmental testing, component characterization, system level hardware in-the-loop testing, and qualification testing to ensure that each element is functional, reliable, and working per its design. Unique capabilities of SDL’s Nano-Satellite Operation Verification and Assessment (NOVA) test facility include: (i) mass and moment of inertia testing using a high resolution mass measurement table to determine the center of gravity and an inverted …

Comparison Of Ch∙∙O, Sh∙∙O, Chalcogen, And Tetrel Bonds Formed By Neutral And Cationic Sulfur-Containing Compounds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The ability of neutral and charged S-compounds to form different sorts of noncovalent bonds is examined by ab initio calculations. Neutrals are represented by CH3SH and fluoro substituted FSCH3; cations are (CH3)3S+, CH3SH2+, and FHSCH3+. Each is paired with N-methylacetamide (NMA) whose O atom serves as common electron donor. Charged species engage in much stronger noncovalent bonds than do the neutral molecules, by as much as an order of magnitude. The strongest noncovalent bond for any system is a O∙∙SF chalcogen bond wherein the O lies directly opposite a S-F covalent bond, amounting to as much as 39 kcal/mol. Second …

Materials At The Atomic Scale: A Key To Exploring The Vast Reaches Of Space, Jr Dennison

Presentations

A critical technology to master for any interplanetary probe is mitigation of risks from spacecraft charging and electrostatic discharge, which cause the majority of environmentally-induced “anomalies.” Understanding how charge is acquired through interaction with space fluxes of electrons, ions and photons; how temperature, dose and fields affect redistributed of charge within spacecraft materials; and what triggers electrostatic arcs all require the study of how charged particles interact with the structure of materials on an atomic scale. This seminar presents an overview of the dynamic properties of materials underlying spacecraft charging, how the material’s structure affects these properties, which properties are …

Improving The Scalability And Usability Of The Public Information Officer Monitoring Application, Rohan D. Shah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis work addresses the limitations of a web application called the Public Information Officer Monitoring Application (PMA). This application helps Public Information Officers (PIOs) to gather, monitor, sort, store, and report social media data during a crisis event. Before this work, PMA was unable to handle large data sets and as a result, it had not been adequately tested with potential users of the application.

This thesis describes changes made to PMA to improve its ability to handle large data sets. After these changes were made, the application was then tested with target users. All test participants found the …

Face Recognition Under Varying Illuminations, Mohammadreza Faraji

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Face recognition under illumination is really challenging. This dissertation proposes four effective methods to produce illumination-invariant features for images with various levels of illuminations. The proposed methods are called logarithmic fractal dimension (LFD), eight local directional patterns (ELDP), adaptive homomorphic eight local directional pat- terns (AH-ELDP), and complete eight local directional patterns (CELDP), respectively.

LFD, employing the log function and the fractal analysis (FA), produces a logarithmic fractal dimension (LFD) image that is illumination-invariant. The proposed FA feature-based method is an effective edge enhancer technique to extract and enhance facial features such as eyes, eyebrows, nose, and mouth.

The proposed …

Image Blur Detection With Two-Dimensional Haar Wavelet Transform, Sarat Kiran Andhavarapu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Efficient detection of image blur and its extent is an open research problem in computer vision. Image blur has a negative impact on image quality. Blur is introduced into images due to various factors including limited contrast, improper exposure time or unstable device handling. Toward this end, an algorithm is presented for image blur detection with the use of Two-Dimensional Haar Wavelet transform (2D HWT). The algorithm is experimentally compared with two other image blur detection algorithms frequently cited in the literature. When evaluated over a sample of images, the algorithm performed on par or better than the two other …

Riparian Vegetation, Colorado River, And Climate: Five Decades Of Spatiotemporal Dynamics In The Grand Canyon With River Regulation, Joel B. Sankey, Barbara Ralston, Paul E. Grams, John C. Schmidt, Laura E. Cagney

Watershed Sciences Faculty Publications

Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen Canyon Dam in 1963. Long-term changes along this highly modified, large segment of the river provide insights for management of similar riparian ecosystems around the world. We analyze vegetation extent based on maps and imagery from eight dates between 1965 and 2009, …

Long-Term Study Of Crowdfunding Platform: Predicting Project Success And Fundraising Amount, Jinwook Chung

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crowdfunding that is the combination word of crowdsourcing and funding makes people can start a business easily. Legislating JOBS act in US played a major role in removing restricted barriers of crowdfunding on public offerings of fence and private funds for small business. The growth speed of crowdfunding takes some beating. Through Kickstarter that is a popular crowdfunding platform and being considered the typical case of crowdfunding, 480 million dollars and more than half a billion dollars were invested in about 19 thousand and 22 projects for 2013 and 2014 respectively. But in spite of the rapid growth, the successful …

Detecting Experts On Quora: By Their Activity, Quality Of Answers, Linguistic Characteristics And Temporal Behaviors, Sumanth Kumar Reddy Nagarur Patil

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Question and answering sites are useful in sharing the knowledge by answering questions. It is a medium of sharing knowledge. Quora is the fastest emerging effective Q&A site, which is the best source of knowledge. Here you can ask a question, and get help in getting answers from people with firsthand experience, and blog about what you know. In this paper, we are investigating and identifying potential experts who are providing the best solutions to the questioner needs. We have considered several techniques in identifying user as an expert or non-expert. We have targeted the most followed topics in Quora …

The Colorado Plateau As A Virtual Laboratory For Mobile Games For Geoscience Education And Relations Between Rock Strength And River Metrics, Natalie Bursztyn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation encompasses two studies: one developing virtual field trips for mobile devices for an innovative approach to lower-division geoscience education, and the other examining the role of rock strength in river erosion and landscape evolution.

The education study involves the development of three virtual field trip modules (Geologic Time, Geologic Structures, and Hydrologic Processes, all free on iTunes and Google Play) that lead students down a virtual Colorado River through Grand Canyon by physically moving around their campus quad, football field or other location, using their GPS-equipped smart phone or tablet. As students reach each location in the scaled …

Competitive Halide Binding By Halogen Versus Hydrogen Bonding: Bis-Triazole Pyridinium, Binod Nepal, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The binding of F-, Cl-, Br-, and I- anions by bis‐triazole‐pyridine (BTP) was examined by quantum chemical calculations. There is one H atom on each of the two triazole rings that chelate the halide via H bonds. These H atoms were replaced by halogens Cl, Br, and I, thus substituting H bonds by halogen bonds. I substitution strongly enhances the binding; Br has a smaller effect, and Cl weakens the interaction. The strength of the interaction is sensitive to the overall charge on the BTP, rising as the binding agent becomes singly and then doubly positively charged. The strongest preference …

A Structurally-Tunable 3-Hydroxyflavone Motif For Visible Light-Induced Carbon Monoxide-Releasing Molecules (Corms), Stacey N. Anderson, Jason M. Richards, Hector J. Esquer, Abby D. Benninghoff, Atta M. Arif, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Molecules that can be used to deliver a controlled amount of carbon monoxide (CO) have the potential to facilitate investigations into the roles of this gaseous molecule in biology and advance therapeutic treatments. This has led to the development of light-induced CO-releasing molecules (photoCORMs). A goal in this field of research is the development of molecules that exhibit a combination of controlled CO release, favorable biological properties (e.g., low toxicity and trackability in cells), and structural tunability to affect CO release. Herein, we report a new biologically-inspired organic photoCORM motif that exhibits several features that are desirable in a next-generation …

Foreland-Directedpropagation Of High-Grade Tectonism In The Deep Roots Of A Paleoproterozoic Collisionalorogen, Sw Montana, Usa, Cailey B. Condit, Kevin H. Mahan, Alexis K. Ault, Rebecca M. Flowers

Geosciences Faculty Publications

The study of deeply exhumed ancient collisional belts offers important constraints on geologic processes and properties complementary to inaccessible portions of the crustal column in active orogens. The ca. 1.8−1.7 Ga Big Sky orogeny in southwest Montana is a major convergent belt associated with the Proterozoic amalgamation of Laurentia. New structural, petrologic, and geochronologic data from the Northern Madison Range, crossing the NE-SW trend of the belt, record key information about the internal dynamics of the orogen. At least two phases of Big Sky−related deformation are preserved, both nearly coeval with peak metamorphic conditions of ∼0.9−0.8 GPa and >700 °C. …

Regioselectivity Of The Interaction Of Temozolomide With Borane And Boron Trifluoride, Okuma Emile Kasende, Jules Tshishimbi Muya, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

MP2 and B3LYP calculations are used to predict the most favorable site of temozolomide toward BH3 and BF3 which are classical Lewis acids. Binding energies, charge transfers, and bond length perturbations of the temozolomide in various complexes indicate that the N12 atom is the preferred attack site for BH3, while BF3 prefers the O17 atom. The interactions are quite strong, as much as 100 kJ/mol for BH3 and more than 60 kJ/mol for BF3. The molecular electrostatic potential surrounding temozolomide is most negative around the O atoms, which is unable to explain the energetic order of binding of the Lewis …

The Online System For Lidar Data Handling And Real Time Monitoring Of Lidar Operations At Alo-Usu, Luis Navarro Dominguez, Vincent B. Wickwar, Jose Gamboa, Marco Milla

Conference publications

t is no longer sufficient to use lidar, such as the Rayleigh lidar at the Atmospheric Lidar Observatory (ALO) at Utah State University (USU), to observe the middle atmosphere and reduce the data to geophysical parameters. Extended operations, with inevitable equipment, data reduction, and analysis improvements, require us to keep careful track of all these changes and how they affect the scientific products. Furthermore, many of the funding agencies and the journals now require us to do, at least, some of this. We have built three interconnected data structures to organize and manage the different hardware and software set- ups …

Temperature Deviations In The Midlatitude Mesosphere During Stratospheric Warmings As Measured With Rayleigh-Scatter Lidar, Leda Sox, Vincent B. Wickwar, Chad Fish, Joshua P. Herron

Conference publications

While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected an extensive set of temperature data for 11 years in the 45–90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the …

Variations In Mesospheric Neutral Densities From Rayleigh Lidar Observations At Utah State University, David L. Barton, Vincent B. Wickwar, Joshua P. Herron, Leda Sox, Luis A. Navarro

Conference publications

A Rayleigh lidar was operated from 1993 to 2004, at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) at the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU). Observations were carried out on over 900 nights, 729 of which had good data starting at 45 km and going upward toward 90 km. They were reduced for absolute temperatures and relative neutral number densities. The latter at 45 km can be put on an absolute basis by using atmospheric models that go up to at least 45 km. The models’ absolute number densities at 45 …

Early Temperatures Observed With The Extremely Sensitive Rayleigh Lidar At Utah State University, Vincent B. Wickwar, Leda Sox, Matthew T. Emerick, Joshua P. Herron, David L. Barton

Conference publications

Rayleigh-scatter lidar observations were made at the Atmospheric Lidar Observatory (ALO) at Utah State University (USU) from 1993–2004 from 45–90 km. The lidar operated at 532 nm with a power-aperture-product (PAP) of ~3.1 Wm2. The sensitivity of the lidar has since been increased by a factor of 66 to 205 Wm2, extending the maximum altitude into new territory, the lower thermosphere. Observations have been extended up to 115 km, almost to the 120 km goal. Early temperatures from four ~4-week periods starting in June 2014 are presented and discussed. They are compared to each other, to the ALO climatol

Conference …

Interdisciplinary Modeling For Water-Related Issues Graduate Course, Laurel Saito, Alexander Fernald, Timothy Link

All ECSTATIC Materials

The science and management of aquatic ecosystems is inherently interdisciplinary, with issues associated with hydrology, atmospheric science, water quality, geochemistry, sociology, economics, environmental science, and ecology. Addressing water resources issues in any one discipline invariably involves effects that concern other disciplines, and attempts to address one issue often have consequences that exacerbate existing issues or concerns, or create new ones (Jørgensen et al. 1992; Lackey et al. 1975; Straskraba 1994) due to the strongly interactive nature of key processes (Christensen et al. 1996). Thus, research and management of aquatic ecosystems must be interdisciplinary to be most effective, but such truly …

Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos

All Physics Faculty 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 …

Forecasting The Response Of Earth's Surface To Future Climatic And Land Use Changes: A Review Of Methods And Research Needs, Jon D. Pelletier, A. Brad Murray, Jennifer L. Pierce, Paul R. Bierman, David D. Breshears, Benjamin T. Crosby, Michael Ellis, Efi Foufoula-Georgiou, Arjun M. Heimsath, Chris Houser, Nick Lancaster, Marco Marani, Dorothy J. Merritts, Laura J. Moore, Joel Pederson, Michael J. Poulos, Tammy M. Rittenour, Joel C. Rowland, Peter Ruggiero, Dylan J. Ward, Andrew D. Wickert, Elowyn M. Yager

Geosciences Faculty Publications

In the future, Earth will be warmer, precipitation events will be more extreme, global mean sea level will rise, and many arid and semiarid regions will be drier. Human modifications of landscapes will also occur at an accelerated rate as developed areas increase in size and population density. We now have gridded global forecasts, being continually improved, of the climatic and land use changes (C&LUC) that are likely to occur in the coming decades. However, besides a few exceptions, consensus forecasts do not exist for how these C&LUC will likely impact Earth-surface processes and hazards. In some cases, we have …