Physical Sciences and Mathematics Commons^™

Differentialgeometry In Brno, Ian M. Anderson

Presentations

This page will provide files supporting Ian Anderson's presentations in Brno, December 2015. The files can be found and downloaded from "Additional Files", below.

The files include:

(1) DifferentialGeometryUSU.mla: This is the Maple Library Archive file which provides all the DifferentialGeometry functionality. Here are Installation Instructions.

(2) DifferentialGeometry.help : this is the latest version of the DifferentialGeometry documentation. Copy this file to the same directory used for DifferentialGeometryUSU.mla (from step (1)).

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.

Street-Level Predictive Modeling Of Nuisance Flooding Verified Via Crowdsourced App Data In Norfolk, Va, J. D. Loftis, H. V. Wang, D R. Forrest

Presentations

No abstract provided.

Estuarine Sediment Dynamics, C. T. Friedrichs

Presentations

No abstract provided.

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

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 …

Re-Emergence Of The Harmful Algal Bloom Species Alexandrium Monilatum In The Chesapeake Bay: Assessing Bloom Dynamics And Potential Health Impacts, Sarah K.D. Pease, Kimberly S. Reece, Wolfgang K. Vogelbein

Presentations

Effective management of harmful algal blooms (HABs) within a region requires an understanding of species-specific HAB spatial and temporal distributions, bloom dynamics, as well as potential health impacts. In 2007, the southern Chesapeake Bay witnessed its first blooms of the HAB species Alexandrium monilatum. Since then, A. monilatum has bloomed in the region almost annually. A. monilatum produces the toxin ‘goniodomin A’ and is suspected in local mass mortalities of oyster larvae (Crassostrea virginica) grown for aquaculture and restoration projects. Representatives from Virginia’s multimillion dollar oyster aquaculture industry recently expressed great concern over A. monilatum impacts to their businesses; field …

Diel Vertical Distribution Patterns Of Zooplankton Along The Western Antarctic Peninsula, Patricia S. Thibodeau, John A. Conroy, Deborah K. Steinberg

Presentations

The Western Antarctic Peninsula (WAP) is a region that has undergone significant change over the past several decades due to unprecedented increases sea surface temperature and decreases in sea ice cover. The ongoing Palmer Antarctica Long-Term Ecological Research (PAL LTER) study shows that these environmental changes are significantly affecting the marine pelagic ecosystem along the WAP. The goal of this study was to analyze diel vertical distribution patterns of zooplankton along the WAP.

Efficacy Of Sediment Remediation Efforts On Pah Contaminant Flux Via Porewater Advection At The Sediment-Surface Water Interface, Julie L. Krask, Michael A. Unger, George G. Vadas, Michele A. Cochran, Aaron J. Beck

Presentations

Groundwater advection at the sediment-surface water interface is an important biogeochemical mechanism controlling the transport and bioavailability of contaminants in estuaries. At sites along the Elizabeth River (VA, USA) where the subterranean environment is heavily contaminated with polycyclic aromatic hydrocarbon (PAH)-rich dense non-aqueous phase liquid (DNAPL), consideration of groundwater-surface water dynamics and associated chemical exchange is critical for effective remediation. Preliminary data suggest that porewater advection in permeable sediments at this location is controlled by a host of physical forcing mechanisms that correspond with total flow estimates of up to 15,000 centimeters/year. Here, the efficacy of sediment remediation strategies, including …

Effects Of Commercial Clam Aquaculture On Biogeochemical Cycling In Shallow Coastal Ecosystems, Annie E. Murphy, Iris C. Anderson, Mark W. Luckenbach

Presentations

The bivalve aquaculture industry is expanding worldwide; sustainability requires improved understanding of its interactions with the environment. As suspension feeders, bivalves, such as clams, reduce primary production through feeding, and thus dampen eutrophication. Additionally, enhanced rates of denitrification, the microbial removal of reactive nitrogen, have been reported in bivalve sediments due to increased organic matter supply through biodeposition; another potential, yet indirect, control on eutrophication. Simultaneously, bivalves can influence local ‘bottom-up’ effects on production by enhancing nutrient regeneration through excretion and microbial mineralization of biodeposits. At clam aquaculture sediments, respiration and nutrient regeneration rates were significantly higher compared to uncultivated …

Informing Social Decision Making: Physical Vulnerability To Sea Level Rise, Alexander D. Renaud, Karinna Nunez, Molly Mitchell, Carl Hershner

Presentations

Social indices on census tract and other geopolitical levels are increasingly being considered to inform decision making. In a flooding and sea level rise context, the likelihood of an area flooding is an important component of adaptation and the decision-making framework, however it is frequently modeled on a continuous scale. In our work, we have developed an index of physical vulnerability to flooding on a census tract scale, specifically designed to complement social vulnerability indices.

The Role Of Oyster In Nitrous Oxide Emissions From Oyster Reefs, Anne Arfkin, Ashley Smyth, Bongkeun Song

Presentations

Oyster microbiomes may play a significant role in the biogeochemical N cycle and N2O emissions in estuarine and coastal ecosystems. Rates of denitrification and N2O production were measured from live oysters and oyster shells collected at a coastal lagoon and a tidal estuary in the Chesapeake Bay. Live oysters had the highest rates of denitrification and N2O production in both study sites. This indicates that oysters are an import N remover and a N2O source in coastal ecosystems.

Quantifying Finfish And Blue Crab Use Of Created Oyster Reefs In The Lower Chesapeake Bay, Bruce W. Pfirrmann, Rochelle D. Seitz

Presentations

Structurally complex reefs created by the eastern oyster Crassostrea virginica provide a host of ecosystem services yet have experienced significant declines, prompting extensive restoration efforts. We investigate the use of created oyster reefs in the lower Bay by mobile finfish and blue crabs with field surveys and diet analysis. The results of this study provide insight into how restoration activities influence estuarine community dynamics and the provision of ecosystem services.

Structural Complexity And Location Affect The Habitat Value Of Restored Oyster Reefs, Melissa Karp, Rochelle Seitz

Presentations

Oyster reefs provide a suite of valuable ecosystem services, such as water filtration, nitrogen sequestration, and provision of habitat and foraging grounds. The global decline of these habitats has had negative economic and ecological impacts to coastal waters worldwide. In the Chesapeake Bay, < 1% of the historic oyster population remains and efforts to restore oyster populations and the services they provide have been increasing. Building reefs that successfully provide specific ecosystem services may require different techniques then previously used, and success may depend on reef morphology, location, and environmental conditions. Settling trays were embedded into previously restored oyster reefs that varied in their structural complexity (rugosity) in multiple rivers in the lower Chesapeake Bay. Trays were collected after 7-weeks, sorted, and species identified and weighed (ash-free dry weight) to obtain species diversity, abundance, and biomass. Species composition data was analyzed using nMDS plots, which showed that salinity was an important driver of differences in species composition. Results of an ANOVA analysis found that species diversity was significantly greater on reefs in the high-salinity rivers compared to reefs in low-salinity rivers. Total organism abundance and biomass were positively correlated with reef structural complexity measures, such as rugosity, oyster clump volume, and oyster biomass. These results suggest that more complex oyster reefs in higher salinity locations may support more diverse and productive benthic communities. This study provides insight into the driving factors that structure oyster reef communities and has important implications for oyster reef restoration design and management.

The Relationship Between Reproduction And Mortality In Triploid Crassostrea Virginica: A Matter Of Economic Importance, Joseph L. Matt, Standish K. Allen

Presentations

The goal of this project is to maximize survival for commercially produced triploid Crassostrea virginica oysters in Virginia. Over the last few years, commercial oyster growers in Virginia have reported significant mortality events of triploid oysters during the spring and summer months. The summer of 2014 was the worst yet, as growers across the state reported summer mortality, most severe on the Eastern shore and in some cases as high as 85% of the crop (Karen Hudson, personal communication). Surviving oysters from some of these mortality events were sent to the Virginia Institute of Marine Science and several of the …

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 …

Tidal Flat Morphodynamics: A Synthesis, C. T. Friedrichs

Presentations

No abstract provided.

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 …

Controls On Suspended Particle Properties And Water Clarity Along A Partially-Mixed Estuary, York River, Virginia, Usa, K. A. Fall, C. T. Friedrichs, G. M. Cartwright, D. G. Bowers

Presentations

The Chesapeake Bay and its associated tidal tributaries, which together form one of the United States’ largest and most important estuaries, are among the many coastal systems where degraded water clarity is a major concern. Despite long-term decreases in sediment input, water clarity over the last 20 years has continued to deteriorate in the Bay and its tributaries (Williams et al., 2010). Analysis of long-term monitoring data (Wang et al., 2010) found that the concentration of total suspended solids (TSS), the regulatory indicator of ‘suspended sediment pollution’, is about as likely to be positively or negatively correlated to sediment loads …

Identification Of Suspended Resilient Pellets In Particles Tracked By A Particle Image Camera System (Pics) In A Muddy Estuary, Grace M. Cartwright, Kelsey A. Fall, Carl T. Friedrichs

Presentations

The Particle Imaging Camera System (PICS) was designed to allow for the measurement of the settling velocity of individual particles in situ by using the smaller particles (< density < 1800kg/m3 ). This classification system, while adequate for suspended dredge plumes, needs to be revisited when the PICS is used in a muddy estuary, such as the York River Estuary, Virginia. Figure 1B shows the settling velocities of particles tracked within a video captured 2.5m from the surface in the Clay Bank region of the York River, plotted against their equivalent spherical diameters. While most of the particles are classified as flocs, as indicated by the blue dots in Figure 1C and the peak in the relative number of particles in Figure 1E, there is still a large number of particles classified as “bed aggregates” (red dots). This number of higher density particles may be unexpected, as this video was captured 4.25m over a “muddy bed” in a natural system with a flood current of 40cm/s. However, biologically compacted mud in the form of resilient pellets (see Figure 2) may be the answer. Bed sediments from five sediment cruises during this study period (Aug 2012 – Nov 2014) were found to be comprised of 86-96% mud (Figure 3A). However, 9-14% of the mud was packaged as resilient pellets (Figure 3B). Sediment captured 38cm above the bed by traps deployed on tripods were found to have 92-98% mud, with 4-14% of the mud packaged as resilient pellets (Figures 3A and B). Pellets isolated from the Apr to Jul 2014 trap were sampled with the PICS to determine the distribution of settling velocities (Ws), particle densities, and the ratio of the long and short axis of the particles. This will be used to identify the pellets in PICS videos captured during the five 6h anchor stations (black lines in Figure 3) where three depths were sampled each hour.

Controls On Bed Erodibility In A Muddy, Partially-Mixed Estuary: York River, Virginia, Usa, Carl T. Friedrichs, Grace M. Cartwright, Patrick J. Dickhut, Kelsey A. Fall

Presentations

Appropriate parameterization of time-dependent erodibility of muddy seabeds is a significant barrier to improved understanding and accurate modelling of sediment dynamics in estuaries and other coastal regions. In an effort to better understand controls on muddy seabed erodibility, bed erodibility and associated bed sediment properties have been measured by our group on cores collected on dozens of cruises over the last decade in the York Estuary (e.g., Dickhudt et al., 2009, 2011; Kraatz, 2013). We have also inferred time-varying erodibility indirectly in the York Estuary over several years by vertically integrating observations of tidally-varying suspended sediment concentration (e.g. Friedrichs et …

Tidal Flat Morphodynamics: A Synthesis, Carl T. Friedrichs

Presentations

Tidal flats commonly occur along coasts where the tidal range is large relative to typical wave height. They can be found where hydrodynamic energy is high or low, where sediments are sandy or muddy, and where shorelines are prograding, retreating, or stable. The study of the morphology and evolution of tidal flats is particularly well suited in the context of morphodynamics since characteristics such as profile shape, bed slope, and grain size clearly and systematically vary as a function of sediment supply and wave and tidal forcing, and the nature of wave- and tide-induced velocities across tidal flats is, in …

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 …

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 …

Comt Chesapeake Bay Hypoxia Modeling, Marjorie A.M. Friedrichs, I. Irby, A. Bever, M. Scully

Presentations

No abstract provided.

Challenges Associated With Operational Modeling Of Low-Oxygen Waters In Chesapeake Bay: Results From A Multiple Modeling Effort, I. D. Irby, M. A.M. Friedrichs, C. T. Friedrichs

Presentations

No abstract provided.

Influence Of Thermal Treatment On Electrical And Physical Properties Of Coated Ceramics, K. Guerch, T. Paulmier, Justin Dekany, Jr Dennison, S. Guillemet-Fritsch, P. Lenormand

Presentations

Technical dielectric materials and ceramics are used in many different high technology industrial areas and especially for spacecraft applications. On satellites, these materials are subjected to extreme conditions due to the space plasma environment. To survive, these ceramic insulators must have exceptional electrical and thermal properties. Boron Nitride (BN) and Aluminum Oxide (Al 2O3) are used in particular because they combine good electrical insulation and high thermal conductivity. However, BN and Al2O3 used in spacecraft interiors are exposed to critical radiation demands, where these insulators are irradiated by electrons with high energies and flux. Charged particles are trapped in the …

Electrical Properties Of Annealed And Coated Boron Nitride Under Electron Beam Irradiation, Kevin Guerch, Thierry Paulmier, Jr Dennison, Justin Dekany, Sophia Guillemet-Fritsch, Pascal Lenormand

Presentations

Technical dielectric materials and ceramics are used in many different high technology industrial areas and especially for spacecraft applications. On satellites, these materials are subjected to extreme conditions due to the space plasma environment. To survive, these ceramic insulators must have exceptional electrical and thermal properties. Boron Nitride (BN) and Aluminum Oxide (Al2O3) are used in particular because they combine good electrical insulation and high thermal conductivity. However, BN and Al2O3 used in spacecraft interiors are exposed to critical radiation demands, where these insulators are irradiated by electrons with high energies and flux. Charged particles are trapped in the ceramics, …