Physical Sciences and Mathematics Commons^™

Determination Of The Free Neutron Lifetime, J. David Bowman, Leah J. Broussard, Stephen M. Clayton, M. S. Dewey, Nadia Fomin, Keith B. Grammer, G. L. Greene, Paul R. Huffman, Anthony T. Holley, Geoffrey L. Jones, Chenyu Liu, Mark Makela, Michael P. Mendenhall, Charles L. Morris, Jonathan Mulholland, K. M. Nollett, Robert W. Pattie, Seppo Penttila, M. Ramsey-Musolf, Daniel J. Salvat, Andy Saunders, Susan J. Seestrom, William M. Snow, A. Steyerl, F. E. Wietfeldt, Albert R. Young, Andrew T. Yue

Robert W. Pattie Jr.

What Controls Bed Erodibility In Muddy, Partially-Mixed Tidal Estuaries?, C. Friedrichs, Grace Cartwright, R. Diaz, K. Fall

Presentations

No abstract provided.

Interactive Comment On “Iodine Oxide In The Global Marine Boundary Layer” By C. Prados-Roman Et Al., Marcelo I. Guzman

Chemistry Faculty Publications

No abstract provided.

Design And Implementation Of An X-Ray Reflectometer System For Testing Multilayer High Energy X-Ray Optics, Danielle Gurgew

Von Braun Symposium Student Posters

No abstract provided.

A 70 Year History Of Coastal Dune Migration And Beach Erosion Along The Southern Shore Of Lake Michigan, Zoran Kilibarda, Craig Shillinglaw

Zoran Kilibarda

A study of aerial photographs from the Indiana Dunes National Lakeshore (adjacent to Michigan City, Indiana, United States of America) revealed that from 1938 to 2008 the Lakeshore’s Mount Baldy dune advanced inland 135 m, at an average rate of 1.9 m/year, while the beach north of the dune receded 98 m, at an average rate of 1.4 m/year. The highest rates of Mount Baldy dune movement (3.3 m/year) occurred concurrently (1965–1973) with highest rates of beach erosion (7.2 m/year). The lowest rates of Mount Baldy dune movement (0.3 m/year) occurred in 1958–1965 period. The highest rates of beach accretion …

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

No abstract provided.

Pre-Breakdown Arcing And Electrostatic Discharge In Dielectrics Under High Dc Electric Field Stress, Allen Andersen, Jr Dennison

Conference Proceedings

Highly disordered insulating materials exposed to high electric fields will, over time, degrade and fail, potentially causing catastrophic damage to devices. Step-up electrostatic discharge (ESD) tests were performed for two common polymer dielectrics, low density polyethylene and polyimide. Prebreakdown transient current spikes or pre-arcs were observed, using both slow and high speed detection. These pre-ESD discharge phenomena are explained in terms of breakdown modes and defect generation on a microscopic scale. The field at which pre-breakdown arcing begins was compared to the onset field for electrostatic discharge at which complete breakdown begins to occur for each material. We present evidence …

Charge Transport And Electron Emission Of Disordered Materials: Extensions Of The Walden-Wintle Model For Charge Injection With Electron Beams, Jr Dennison, Alec Sim, Gregory Wilson, Jodie C. Gillespie

Presentations

No abstract provided.

Pre-Breakdown Arcing And Electrostatic Discharge In Dielectrics Under High Dc Electric Field Stress, Allen Andersen, Jr Dennison

Presentations

No abstract provided.

Sedimentology Of The Upper Scotland Formation (Eocene), Barbados, Krishna Mahabir, Nazrul I. Khandaker, Jay P. Persaud, Stanley Schleifer

Publications and Research

Representative samples collected from the Lower Scotland Formation (Eocene) outcropping in northeastern Barbados were investigated in conjunction with overall facies distribution and stratigraphic and sedimentological characteristics to interpret depositional environment and provenance of the fine-grained clastics. The Lower Scotland Formation is, for the most part, a fine-grained clastic-dominated sequence with occasional thin intercalations of gypsum, ironstone, and kaolinite. Distinctive deep-water-facies have been well-documented in dark gray shale units containing load cast, flutes, grooves and prods. In addition, turbiditic brown sandstone with a sharp erosive base and pelagic caps also characterize the base of the formation. Notable marine fauna observed include …

End Of The Cosmic Neutrino Energy Spectrum, Luis A. Anchordoqui, V. Barger, H. Goldberg, J.G. Learned, D. Marfatia, S. Pakvasa, T. C. Paul, T. J. Weiler

Publications and Research

There may be a high-energy cutoff of neutrino events in IceCube data. In particular, IceCube does not observe either continuum events above 2PeV, or the Standard Model Glashow-resonance events expected at 6.3PeV. There are also no higher energy neutrino signatures in the ANITA and Auger experiments. This absence of high-energy neutrino events motivates a fundamental restriction on neutrino energies above a few PeV. We postulate a simple scenario to terminate the neutrino spectrum that is Lorentz-invariance violating, but with a limiting neutrino velocity that is always smaller than the speed of light. If the limiting velocity of the neutrino applies …

A Case Study Of How Ninth Grade Mathematics Students Construct Knowledge During A Productive Failure Model, Amy F. Westbrook Dr.

Georgia Educational Research Association Conference

The purpose of this qualitative study was to explain how ninth grade mathematics students at a rural high school in Georgia constructed knowledge through student talk when problem solving using Kapur’s (2012) productive failure design. An embedded case study design was used to understand how a group of students constructed knowledge through their use of talk, persistence during the task, and use of prior knowledge while working on a productive failure modeled task. Triangulation resulted from the collected data from multiple sources, which included videotaping, interviewing, and analyzing student artifacts. Utilization of the constructivist perspectives of Vygotsky (1934/1962), Piaget (1971), …

Stomatal Physics, Katie Sweet, Keith Mott, David Peak

Browse All Undergraduate research

Stomata, microscopic pores on a leaf’s surface, regulate the diffusion of CO2 from, and the diffusion of water vapor to, the air.

Stomata are responsible for fixing essentially all carbon in the biosphere and generating over 90% of the water vapor in the atmosphere over landmasses.

Exactly how stomata respond to temperature, light intensity, and ambient CO2 and humidity, is still a matter of active debate.

Most research probing this question focuses on identifying and unraveling complicated biochemistry. Recent investigations in our laboratory, however, indicate that much of stomatal behavior can be understood in terms of a simple vapor phase …

Cathodoluminescence Events Coincident With Muon Detection, Kenneth Zia, Justin Dekany, Jr Dennison

Presentations

Samples of highly disordered insulating material have been irradiated with keV electron beams, resulting in three forms of electron induced light emission with differing duration: arcs (duration), “flares” (~100 s), and cathodoluminescence (as long as beam is on) [Dennison, 2013]. The arc and cathodoluminescence phenomena are well understood, while the flares’ origins are not. Flares were observed at intervals of ~2 per hr. This is within a factor of 2 for the expected muon cross section at an altitude of Logan, UT (1370 m) caused by high altitude cosmic rays; those high energy particles could have deposited sufficient energy throughout …

Lifetimes Of Polymeric Dielectrics: A Dual-Defect Model, Allen Andersen, Jr Dennison

Presentations

Electrostatic discharge (ESD) can cause catastrophic failures in electronic devices. Estimating the lifetime of dielectrics under prolonged high field exposure is a major design concern for applications including spacecraft, high voltage DC power transmission, and semiconductor electronics. Dielectric strengths listed in engineering handbooks are primarily based on cursory measurements with poor repeatability and tend to overestimate ESD fields in real applications. Standard measurements subject test samples to ~500 V/s ramp rates until breakdown. We present the results of ESD studies in two prototypical polymer dielectrics using a ramp rate of ~20 V/4s until breakdown together with tests applying a static …

Space Effects Survivability Testing, Lisa Montierth Phillipps, Jr Dennison, Kent Hartley, Robert H. Johnson, Justin Dekany, James S. Dyer

Presentations

A versatile test facility has been designed to study the effects of space environment fluxes and radiation damage on small scale materials samples, system components, and small satellites. Cost-effective long-duration testing for potentially environmental-induced modifications is increasingly more important as small satellite programs have longer mission lifetimes, expand to more harsh environments, make more diverse and sensitive measurements, minimize shielding to reduce mass, and utilize more compact and sensitive electronics. The facility simulates environmental components including the neutral gas atmosphere, the solar spectrum, electron plasma fluxes, and temperature. The UV/VIS/NIR solar spectrum is simulated using a class AAA Solar Simulator …

Cathodolumiescence Studies Of The Density Of States Of Disordered Silicon Dioxide, Jr Dennison, Amberly Evans Jensen

Presentations

Electron bombardment measurements have shown that disordered SiO2 exhibits cathodoluminescence, with an overall intensity that varies with incident electron beam energy and current density, sample temperature, exposure time, and wavelength. A simple model based on the defect density of states—used to explain electron transport in highly disordered insulating materials—has been extended to predict the relative cathodoluminescent intensity and spectral radiance for disordered SiO 2 as a function of these variables. The spectral radiance exhibited four distinct bands, corresponding to four distinct energy distributions of defect states within the band gap; each showed different temperature dependence. These localized defect or “trap” …

Modeling The Energy Dependent Cathodoluminescent Intensity Of A Carbon Composite Material, Justin Christensen, Kelby T. Peterson, Justin Dekany, Jr Dennison

Presentations

When highly disordered insulating materials are subjected to energetic electron bombardment they can emit photons. This process is termed “cathodoluminescence.” This occurs in the space plasma environment and is an important phenomenon to understand when designing any object to be put into space. Light emitted from spacecraft materials can affect optical detection, and can cause stray-light contamination in space-based observatories. The Materials Physics Group at Utah State University uses an ultra-high vacuum chamber equipped with electron guns and a cryostat to control the sample temperature to simulate the space environment and to observe its affects on sample materials. Previous studies …

Discharge Breakdown Analyses, Sam Hansen, Jr Dennison, Allen Andersen

Presentations

Material breakdown due to Electrostatic discharge (ESD) is the primary cause of spacecraft damage due to environment interactions in space. This occurs when the space plasma fluxes charge a craft to high voltages where insulating craft materials then break down. This failure allows current to flow freely through the material, this can damage or destroy onboard electrical systems. My project focuses on the effects of these breakdowns on suspect materials commonly used for electrical insulation in space. The USU Material Physics Group has performed ESD tests on hundreds of samples to date. The ESD damage sites of these samples have …

Applications Of The Wei-Lachin Multivariate One-Sided Test For Multiple Outcomes On Possibly Different Scales, John M. Lachin

GW Biostatistics Center

Many studies aim to assess whether a therapy has a beneficial effect on multiple outcomes simultaneously relative to a control. Often the joint null hypothesis of no difference for the set of outcomes is tested using separate tests with a correction for multiple tests, or using a multivariate T2-like MANOVA or global test. However, a more powerful test in this case is a multivariate one-sided or one-directional test directed at detecting a simultaneous beneficial treatment effect on each outcome, though not necessarily of the same magnitude. The Wei-Lachin test is a simple 1 df test obtained from a simple …

Timed/Saber Satellite Investigations Of Mesospheric Gravity Wave Variances Over The Andes, Jonathan R. Pugmire

Jonathan Pugmire

Focusing on data from the SABER instrument aboard the TIMED satellite temperature variances are determined as a function of altitude to quantify small scale gravity waves. This was done using IDL software to extract all the temperature profile measurements that were measured by SABER within a limited geographical area, centered on our ground-based optical imager at Cerro Pachon, Chile (30.3°S, 70.7°S). Then large-scale tidal waves, with wavenumbers 0-6, were removed from each profile revealing the gravity wave perturbations. The temperature variance were computed and recorded at several altitudes. Temperature variances reveal possible increased activity due to mountain waves. Mountain waves …

Analysis Of The Impact Of Climate Change On Stormwater Design Storms For The State Of South Carolina, Derek Hutton, Nigel B. Kaye, William D. Martin Iii

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges

Use Of A Volunteer Monitoring Program To Assess Water Quality In A Tmdl Watershed Utilized For Recreational Use, Pickens County, South Carolina, Travis H. Nation, Leah A. Johnson

S.C. Water Resources Conference

Proceedings of the 2014 South Carolina Water Resources Conference, held October 15-16, 2014 at the Columbia Metropolitan Convention Center.

Adjusting Nrcs Curve Number For Rainfall Durations Less Than 24 Hours, Michael E. Meadows

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges

Storm Water Damage Risk Assessment Along The South Carolina Heritage Trail, C Alex Pellett, David White, Patrick Mcmillan, Dara Park, William Bridges

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges

Watershed Management – Holistic Policies And Practices That Achieve Sustainable Water Quality Solutions, Graham W. Rich

S.C. Water Resources Conference

Proceedings of the 2014 South Carolina Water Resources Conference, held October 15-16, 2014 at the Columbia Metropolitan Convention Center

Scaling Up Watershed Model Parameters—Flow And Load Simulations Of The Edisto River Basin, Toby D. Feaster, Stephen T. Benedict, Jimmy M. Clark, Paul M. Bradley, Paul A. Conrads

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges

Improving The Robustness Of Uncertainty Algorithms In Quantification Of Uncertainty In Water Balance Forecasting, S Samadi, D L. Tufford, G J. Carbone

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges

Optimization Of A Managed Aquifer Recharge Network, J C. Chrispell, M W. Farthing, K R. Fowler, S E. Howington, E W. Jenkins, S Dutta, B Ji

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges

Demonstrating Subsurface Drip Irrigation As A Climate Adaptation Strategy For Sustainable Crop Production In South Carolina, Jose Payero, Rebecca Davis, Ahmad Khalilian

S.C. Water Resources Conference

2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenges