Physical Sciences and Mathematics Commons^™

Measurement Of Charging And Discharging Of High Resistivity Materials Spacecraft Materials By Electron Beams, Ryan Hoffmann, Joshua L. Hodges, Jesse Hayes, Jr Dennison

Conference Proceedings

New instrumentation has been developed for in situ measurements of the electron beam- induced surface voltage of high resistivity spacecraft materials in an existing ultra-high vacuum electron emission analysis chamber. Design details, calibration and characterization measurements of the system are presented, showing sensitivity to a range of surface voltages from12000 V, with resolution surface, using a paddle attached to a vacuum compatible stepper motor mounted within a hemispherical grid retarding field analyzer. These electrodes formed one end of a floating charge transfer probe that enabled measurements to be made by a standard electrostatic field probe external to the vacuum chamber. …

Comparison Of Exact Methods For Analyzing Family-Based Samples, Abbie Lundgreen

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Family-based association tests are used to identify genes that increase the risk of developing a disease, while controlling for spurious associations caused by population structure. The exact family-based association test, exact FBAT, is a unified approach which can be app lied to tests of different genetic models, sampling designs, null hypotheses , and missing parental information.

The purpose of this report is to compare the power of the exact FBAT with two other tests, exact conditional logistic regression (CLR) and the exact trend test for clustered data (QEM). Pedigrees of sibships were simulated based upon a variety of different parameters, …

The Classification Of Simple Lie Algebras In Maple, D. Russell Sadler

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Lie algebras are invaluable tools in mathematics and physics as they enable us to study certain geometric objects such as Lie groups and differentiable manifolds. The computer algebra system Maple has several tools in its Lie Algebras package to work with Lie algebras and Lie groups. The purpose of this paper is to supplement the existing software with tools that are essential for the classification of simple Lie algebras over C.

In particular, we use a method to find a Cartan subalgebra of a Lie algebra in polynomial time. From the Cartan subalgebra we can compute the corresponding root system. …

The Effects Of Model Misspecification On Linear Regression Coefficients As Applicable To Solar And Linear Terms, Troy A. Wynn, Vincent B. Wickwar

Reports

Determining atmospheric solar response from data is typically done by fitting a linear model to the data using a least squares approximation. These models typically include a solar proxy that follows the 11 year solar intensity variation, as well as a linear cooling trend. In this paper it is argued that such a regression model is flawed in that the atmospheric solar response might be out of phase with the solar input. And if so, the phase difference between solar input and atmospheric solar response can significantly bias the linear regression coefficient and attenuate the solar coefficient. This result is …

Convection: The Likely Source Of The Medium-Scale Gravity Waves Observed In The Oh Airglow Layer Near Brasilia, Brazil, During The Spreadfex Campaign, Sharon L. Vadas, Michael J. Taylor, Pierre-Dominique Pautet, P. A. Stamus, David C. Fritts, H. L. Liu, F. T. São Sabbos, V. T. Batista, H. Takahashi, V. T. Rampinelli

Publications

Six medium-scale gravity waves (GWs) with horizontal wavelengths of λH=60–160 km were detected on four nights by Taylor et al. (2009) in the OH airglow layer near Brasilia, at 15° S, 47° W, during the Spread F Experiment (SpreadFEx) in Brazil in 2005. We reverse and forward ray trace these GWs to the tropopause and into the thermosphere using a ray trace model which includes thermospheric dissipation. We identify the convective plumes, convective clusters, and convective regions which may have generated these GWs. We find that deep convection is the highly likely source of four of these GWs. We pinpoint …

Development Of A Cubesat Pico-Satellite, Phillip Anderson, Jan Sojka

Posters

The CubeSat Project was developed by California Polytechnic State University (CalPoly) and Stanford University in order to provide launch opportunities to universities previously unable to afford access to space. Today, it provides low-cost launch opportunities to students, government, and business. The CubeSat program is able to provide these low-cost launch opportunities by defining a common form factor and design guidelines. All satellites conforming to the regulations are able to be deployed from a standard, flight-proven deployment system called a PPOD. by adhering to the prescribed form factor and safety requirements, necessary documents and export licenses and more easily obtained. CalPoly …

Gathering Leadership Momentum Across Great Distances: Creating An Online Community Of Practice, Erin Dini-Davis, Danielle Theiss-White

Library Faculty & Staff Publications

At the 2007 Mountain Plains Library Association Leadership (MPLA) Institute, held in New Mexico, USA, eight academic librarians formed an online multi-state, multigenerational community of practice. MPLA is a twelve-state library association within the United States. Using Google Groups™, the members formed an online environment called the MPLA Community of Practice for continuing development of the leadership skills presented at the Institute. These early-career librarians represent diverse educational backgrounds and work in libraries serving varied populations with differing disciplinary emphases. The group meets monthly with each member preparing and facilitating online discussions, complete with personal assessments, topical readings, and questions. …

Modeling Integrated Decisions For A Municipal Water System With Recourse And Uncertainties: Amman, Jordan, David E. Rosenberg, Jay Lund

Civil and Environmental Engineering Faculty Publications

Stochastic mixed-integer optimization is used to identify a portfolio of long- and short-term supply and conservation actions for a municipal water system to cost-effectively accommodate a distribution of water shortages. Alternative robust, grey-number, and best/worst case formulations systematically explore implications of uncertainties in action costs, life spans, water volumes gained or saved, shortage levels, and shortage probabilities. A detailed example for Amman, Jordan considers 23 potential actions. Results show: (1) remarkable consistency occurs across the different modeling approaches. (2) Conserving water—reducing leakage and targeting select customers to install water efficient appliances—plays an important and growing role over time. (3) A …

Storm-Time Density Enhancements In The Middle Latitude Dayside Ionosphere, R. A. Heelis, Jan Josef Sojka, M. David, Robert W. Schunk

All Physics Faculty Publications

Enhancements of the total electron content (TEC) in the middle-latitude dayside ionosphere have often been observed during geomagnetic storms. The enhancements can be as large as a factor of 2 or more, and many sightings of such structures have occurred over the United States. Here we investigate the effectiveness of an expanded convection electric field as a mechanism for producing such ionospheric enhancements. As a test case, we examine the storm period of 5–7 November 2001, for which observations from the DMSP F13 are used to drive the Time Dependent Ionospheric Model (TDIM). Our findings indicate that at favorable universal …

Removal Of Nonconstant Daily Variation By Means Of Wavelet And Functional Data Analysis, I. Maslova, P. Kokoszka, Jan Josef Sojka, L. Zhu

All Physics Faculty Publications

We propose a novel approach based on wavelet and functional principal component analysis to produce a cleaner index of the intensity of the symmetric ring current. We use functional canonical correlations to show that the new approach more effectively extracts symmetric global features. The main result of our work is the construction of a new index, which is an improved version of the existing wavelet-based index (WISA) and the old Dst index, in which a constant daily variation is removed. Here, we address the fact that the daily component varies from day to day and construct a “cleaner” index by …

Characterizing The Lower Ionosphere With A Space - Weather - Aware Receiver Matrix, D. D. Rice, R. D. Hunsucker, J. V. Eccles, Jan Josef Sojka, J. W. Raitt, J. J. Brady

All Physics Faculty Publications

Current ionospheric models are very good at specifying regular diurnal and seasonal variations of the E and F regions of the ionosphere. Less is known about the behavior of the D region, although progress has recently been made with models such as the Data-Driven D-Region (DDDR). However, significant departures from modeled behaviors are observed even during solar minimum conditions, due to complex ionospheric weather effects arising from both solar activity above and terrestrial atmospheric perturbations below. The D-region perturbations directly affect VLF communications, and also affect daytime absorption of frequencies from LF through HF. Perturbations in the E and F …

Plasmasphere And Upper Ionosphere Contributions And Corrections During The Assimilation Of Gps Slant Tec, D. C. Thompson, L. Scherliess, Jan Josef Sojka, Robert W. Schunk

All Physics Faculty Publications

Total electron content (TEC) measurements from ground stations to Global Positioning System (GPS) satellites provide a rich source of information about the Earth's ionosphere. These data comprise a significant part of the typical data set used by various data ingestion and assimilation models of the ionosphere. For example, the Utah State University (USU) Global Assimilation of Ionospheric Measurements (GAIM) data assimilation model uses slant TEC, along with various other types of data, to obtain a global reconstruction of the ionosphere. There are presently two different USU GAIM models: the Gauss‐Markov Kalman Filter (GAIM‐GM), which is operational at the NASA Community …

A Frequency Agile, Distributed Sensor System To Address Space Weather Effects Upon Ionospherically Dependent Systems, D. D. Rice, J. V. Eccles, Jan Josef Sojka, J. W. Raitt, J. Brady, R. D. Hunsucker

All Physics Faculty Publications

The outstanding problem faced by operational systems that utilize the ionosphere is that ionospheric weather variability is comparable to the ionospheric climate variability. However, the number of simultaneous measurements is orders of magnitude too few to resolve the weather scales that are impacting systems. We describe a prototype distributed array of affordable passive radio beacon monitors combined with a central data repository and a data-model analysis system called the Frequency-Agile Distributed Sensor System (FADSS). By monitoring signals from terrestrial VLF/HF radio beacons the FADSS tracks changes in the D, E, or F regions and makes appropriate modifications to the ionospheric …

Observations Of Ionospheric Heating During The Passage Of Solar Coronal Hole Fast Streams, Jan Josef Sojka, R. L. Mcpherron, A. P. Van Eyken, M. J. Nicolis, C. J. Heinselman, J. D. Kelley

All Physics Faculty Publications

Using ionospheric temperature measurements made continuously by the Poker Flat Incoherent Scatter Radar (PFISR) and EISCAT Svalbard Radar (ESR) during the International Polar Year (IPY), we provide evidence for directly driven ionospheric heating associated with the solar wind corotating interaction region (CIR). Both ESR and PFISR operated almost continuously during the IPY, which began on 1 March 2007. During this period 55 CIR events occurred and when ISR observations were available during these events ionospheric heating was observed. This study is the first comprehensive observation of ionospheric heating by CIRs demonstrated through case study comparisons and statistically over the 1-year …

Detecting A Stochastic Gravitational-Wave Background: The Overlap Reduction Function, Lee Samuel Finn, Shane L. Larson, Joseph D. Romano

All Physics Faculty Publications

Detection of a gravitational-wave stochastic background via ground or space-based gravitational-wave detectors requires the cross correlation of the response of two or more independent detectors. The cross correlation involves a frequency-dependent factor—the so-called overlap reduction function or Hellings-Downs curve—that depends on the relative geometry of each detector pair, i.e., the detector separations and the relative orientation of their antenna patterns (beams). An incorrect formulation of this geometrical factor has appeared in the literature, leading to incorrect conclusions regarding the sensitivity of proposed detectors to a stochastic gravitational-wave background. To rectify these errors and as a reference for future work we …

Bubble Behavior In Nucleate Boiling Experiment Aboard The Space Shuttle, Justin P. Koeln, Jeffrey C. Boulware, Heng Ban

All Physics Faculty Publications

Boiling dynamics in microgravity need to be better understood before heat transfer systems based on boiling mechanism can be developed for space applications. This paper presents the results of a nucleate boiling experiment aboard Space Shuttle Endeavor (STS- 108). The experiment utilized nickel-chromium resistance wire to boil water in microgravity, and the data was recorded with a CCD camera and six thermistors. This data was analyzed to determine the behavior of bubble formation, detachment from the heating wire, and travel in the water with effects of drag on bubble movement. Bubbles were observed to be ejected from the wire, travel …

Core-Level Shifts At The Pt/W(110) Monolayer Bimetallic Interface, D. Mark Riffe, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang

All Physics Faculty Publications

We have measured W and Pt 4f7/2 core-level photoemission spectra from interfaces formed by ultrathin Pt layers on W(110), completing our core-level measurements of W(110)-based bimetallic interfaces involving the group-10 metals Ni, Pd, and Pt. With increasing Pt coverage the sequence of W spectra can be described using three interfacial core-level peaks with binding-energy (BE) shifts (compared to the bulk) of −0.220 ± 0.015, −0.060 ± 0.015, and +0.110 ± 0.010 eV. We assign these features to 1D, 2D pseudomorphic (ps), and 2D closed-packed (cp) Pt phases, respectively. For ~1 ps ML the Pt 4f7/2 BE is 71.40 ± 0.02 …

Critical Level Interaction Of A Gravity Wave With Background Winds Driven By A Large-Scale Wave Perturbation, M. K. Ejiri, Michael J. Taylor, T. Nakamura, S. J. Franke

All Physics Faculty Publications

As part of the Maui-Mesosphere and Lower Thermosphere program, data from the Utah State University Mesospheric Temperature Mapper (MTM) and the University of Illinois Meteor Wind Radar (MWR) have been used to investigate wave-driven dynamical interactions in the upper mesosphere at low latitudes. On 29 June 2003, short-period (20 min) gravity waves (GWs) were imaged in the MTM in the near-infrared OH and O2 airglow emissions for most of the night from 0700 to 1500 UT. The GWs were observed to disappear rapidly in the O2 data (peak altitude: 94 km) around 1400 UT but remained evident in the lower …

The Spread F Experiment (Spreadfex): Overview And Summary Of The Spread F Experiment (Spreadfex), D. C. Fritts, M. A. Abdu, B. R. Batista, I. S. Batista, P. P. Batista, R. Buriti, B. R. Clemesha, T. Dautermann, E. De Paula, B. J. Fechine, B. G. Fejer, D. Gobbi, J. Haase, F. Kamalabadi, B. Luughman, P. P. Lima, H. L. Liu, A. F. Medeiros, P. D. Pautet, D. M. Riggin, F. São Sabbas, J. H.A. Sobral, P. Stamus, H. Takahashi, Michael J. Taylor, S. L. Vadas, C. Wrasse

All Physics Faculty Publications

The Spread F Experiment, or SpreadFEx, was performed from September to November 2005 to define the potential role of neutral atmosphere dynamics, primarily gravity waves propagating upward from the lower atmosphere, in seeding equatorial spread F (ESF) and plasma bubbles extending to higher altitudes. A description of the SpreadFEx campaign motivations, goals, instrumentation, and structure, and an overview of the results presented in this special issue, are provided by Fritts et al. (2008a). The various analyses of neutral atmosphere and ionosphere dynamics and structure described in this special issue provide enticing evidence of gravity waves arising from deep convection in …

Overview And Summary Of The Spread F Experiment (Spreadfex), D. C. Fritts, M. A. Abdu, B. R. Batista, I. S. Batista, P. P. Batista, R. Buritii, B. R. Clemesha, J. Comberiate, T. Dautermann, E. De Paula, B. J. Fechine, B. G. Fejer, D. Gobbi, J. Haase, F. Kalamabadi, B. Laughman, P. P. Lima, H. L. Liu, A. Medeiros, Pierre-Dominique Pautet, F. Sao Sabbas, J. H.A. Sobral, P. Stamus, H. Takahashi, Michael J. Taylor, S. L. Vadas, C. Wrasse

All Physics Faculty Publications

We provide here an overview of, and a summary of results arising from, an extensive experimental campaign (the Spread F Experiment, or SpreadFEx) performed from September to November 2005, with primary measurements in Brazil. The motivation was to define the potential role of neutral atmosphere dynamics, specifically gravity wave motions propagating upward from the lower atmosphere, in seeding Rayleigh-Taylor instability (RTI) and plasma bubbles extending to higher altitudes. Campaign measurements focused on the Brazilian sector and included ground-based optical, radar, digisonde, and GPS measurements at a number of fixed and temporary sites. Related data on convection and plasma bubble structures …

Characterization Of Electrical Materials Properties Related To Spacecraft Charging, John R. Dennison

All Physics Faculty Publications

No abstract provided.

Engineering Tool For Temperature, Electric Field And Dose Rate Dependence Of High Resistivity Spacecraft Materials, John R. Dennison, Alec Sim, Jerilyn Brunson, Steven Hart, Jodie Gillespie, Justin Dekany, Charles Sim, Dan Arnfield

All Physics Faculty Publications

An engineering tool has been developed to predict the equilibrium conductivity of common spacecraft insulating materials as a function of electric field, temperature, and adsorbed dose rate based on parameterized, analytic functions derived from physics-based theories. The USU Resistivity Calculator Engineering Tool calculates the total conductivity as the sum of three independent conductivity mechanisms: a thermally activated hopping conductivity, a variable range hopping conductivity, and a radiation induced conductivity using a total of nine independent fitting parameters determined from fits to an extensive data set taken by the Utah State University Materials Physics Group. It also provides a fit for …

Migration And Gender: The Case Of A Farming Ejido In Calakmul, Mexico, Claudia Radel, Birgit Schmook

Environment and Society Faculty Publications

As one of Mexico’s last agricultural frontiers, southern Mexico’s rural farming municipality of Calakmul has long been marked by rural in-migration. In the last few years this process has given place to an explosive growth of primarily male labor out-migration, particularly to the United States. The authors trace the outlines of the migration process from the perspective of one rural Calakmul community, to explore effects of men’s transnational migration on the household and community status of the women remaining behind. Analysis is based on quantitative data collected in 2004 from 25 households, and on in-depth qualitative interviews in 2005 with …

Hydrologic Interdependencies And Human Cooperation: The Process Of Adapting To Droughts, Joanna Endter-Wada, Theresa Selfa, Lisa Welsh

Environment and Society Faculty Publications

The Bear River Basin, which includes portions of Idaho, Utah, and Wyoming in the United States, has a dynamic history of human hydrologic adaptations in relation to a highly variable water supply. These adaptations are embedded in a geographical setting highly influenced by the legal, policy, and institutional contexts that govern allocation of water in this generally arid region. In response to several years of drought and a historically low water year in 2004, water users in the Bear River Basin tested the efficacy of the “law of the river” and innovative agreements that they had negotiated in recent years …

Integrated Water Resources Management And Modeling At Multiple Spatial Scales In Jordan, David E. Rosenberg

Civil and Environmental Engineering Faculty Publications

Water shortages from intermittent public supplies are a major and expanding problem in the Hashemite Kingdom of Jordan. Yet individual users, utility managers, and government officials can improve access or cope with shortages in many ways. New supplies, more efficient use of existing resources, long-term investments to expand infrastructure and reduce leakage, and short-term measures to flexibly transfer, ration, or curtail some uses represent several different approaches for management. This paper reviews three separate systems analysis that use stochastic optimization with recourse. Analysis for individual residential users, the water utility serving 2.2 million residents in the capital Amman, and the …

Los Maridos En El 'Norte'; Las Mujeres ¿Bien Gracias?, B. Schmook, Claudia Radel

Environment and Society Faculty Publications

La migración de mexicanos hacia Estados Unidos ha sido una constante en las relaciones entre ambas naciones desde hace más de siglo y medio, pero se ha intesificado considerablemente en las últimas tres décadas. Factores diversos como la vecindad geográfica, tendencias demográficas y laborales, la creciente integrción económica, la crisis del campo y las intensas relaciones e intercambios entre los dos países, hacen inevitable estos movimientos poblacionales.

Relevance Of Ground-Based Electron-Induced Electrostatic Discharge Measurements To Space Plasma Environments, Jennifer A. Roth, Ryan Hoffmann, John R. Dennison, Jonathon R. Tippetts

All Physics Faculty Publications

Electron-induced electrostatic discharge (ESD) can lead to severe spacecraft anomalies. It is crucial to the success of space missions that the likelihood of ESD occurrence is understood and mitigated. To aid in predicting ESD occurrence, a model for electric fields above and below the charge layer inside an electronirradiated dielectric material was developed. An instrumentation system was also designed to induce and detect ESD events. Because ESD events with a wide range of maximum current values can occur over a range of time intervals, multiple simultaneous detection methods were employed as charge was accumulated on a sample surface; these included …

Thin Wire Nucleate Boiling Of Water In Sustained Microgravity, Justin P. Koeln, Heng Ban, John R. Dennison

All Physics Faculty Publications

The advancement of small satellite technology relies on the development of effective thermal management systems that can be made smaller, safer, and more robust. This paper presents the results and analysis of a nucleate boiling experiment in sustained microgravity aboard the Space Shuttle Endeavor (STS-108). Bubble growth and departure were observed from a single and a braid of three 0.16 mm diameter and 80 mm long nickel-chromium resistive wires. Analysis showed that the braided wire provides a unique surface configuration to enhance the onset of boiling. The braid of wires was also observed to produce several bubble explosions; this is …