Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Spacecraft charging (4)
- Ionosphere (2)
- Pulsed electroacoustic method (2)
- Surface conditions (2)
- Aerospace testing (1)
-
- Arc damage (1)
- Atmospheric humidity (1)
- Bifurcations (1)
- Breakdown field strength (1)
- CBD-containing lipids (1)
- Charge distribution (1)
- Chile (1)
- Composite insulation (1)
- Conductivity measurement (1)
- Contamination (1)
- Dielectric breakdown (1)
- Dielectric films (1)
- Dielectric materials (1)
- Earth's surface (1)
- Earthquake (1)
- Electrodynamics (1)
- Electron irradiated polymers (1)
- Electron yield (1)
- Electron yields (1)
- Electrostatic discharges (ESDs) (1)
- Embedded charge (1)
- Equilibrium (1)
- Filled Hexagon (1)
- Food processing (1)
- GPU offloading (1)
Articles 1 - 18 of 18
Full-Text Articles in Physics
Effects Of Exposure To Atmospheric Humidity On Breakdown Field Strength Measurements Of Polymers, Megan Loveland Dewaal
Effects Of Exposure To Atmospheric Humidity On Breakdown Field Strength Measurements Of Polymers, Megan Loveland Dewaal
Physics Capstone Projects
This study investigates the effects of absorbed water introduced via exposure to atmospheric humidity on electrostatic breakdown field strength measurements of polymers. Conducting breakdown tests under sample conditions appropriate for different applications is essential. If the breakdown field strength is overestimated for an application, an insulator may be used inappropriately in high electric fields where they are more likely to break down. Comparisons are made between: sets of pristine samples, samples that underwent a thorough vacuum bake out to remove absorbed water, and samples subject to subsequent incremental prolonged atmospheric exposure. These investigated the effects of absorbed water and determined …
Spacecraft Charging Test Considerations For Composite Materials, Allen Andersen, Wousik Kim, J. R. Dennison, Brian Wood, Todd A. Schneider, Jason Vaughn, Kenneth H. Wright Jr., Nelson W. Green, Eric Suh, Joel Schwartz, Abdul-Majeed Azad
Spacecraft Charging Test Considerations For Composite Materials, Allen Andersen, Wousik Kim, J. R. Dennison, Brian Wood, Todd A. Schneider, Jason Vaughn, Kenneth H. Wright Jr., Nelson W. Green, Eric Suh, Joel Schwartz, Abdul-Majeed Azad
Journal Articles
Composite materials present a growing challenge for spacecraft charging assessments. We review some recent lessons learned for charging tests of composite materials using both parallel-plate and electron beam test geometries. We also discuss examples of materials that exhibit significant variations between samples, despite them all having the same trade name.
Inertial Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, Cade Pankey, John M. Edwards
Inertial Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, Cade Pankey, John M. Edwards
All Physics Faculty Publications
As seen by an observer in the rotating frame, the earth’s small spheroidal deformations neutralize the centrifugal force, leaving only the smaller Coriolis force to govern the “inertial” motion of objects that move on its surface, assumed smooth and frictionless. Previous studies of inertial motion employ weakly spheroidal equations of motion that ignore the influence of the centrifugal force and yet treat the earth as a sphere. The latitude dependence of these equations renders them strongly nonlinear. We derive and justify these equations and use them to identify, classify, name, describe, and illustrate all possible classes of inertial motion, including …
Round Robin Tests Of Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements, Zachary Gibson, J. R. Dennison, Virginie Griseri
Round Robin Tests Of Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements, Zachary Gibson, J. R. Dennison, Virginie Griseri
Physics Student Research
Charge accumulation and migration can be studied using the pulsed electroacoustic (PEA) method to directly measure internal charge distributions in dielectric materials. This study aims to compare measurements using PEA systems constructed in labs at Utah State University and Université Paul Sabatier to establish confidence in comparing PEA results between different PEA systems. While there is good agreement in data measured for pristine samples with DC bias applied and no charge embedded, there are discrepancies in the data when measuring irradiated samples with embedded charge. The overall characteristics of charge distributions measured with both systems is clearly the same, but …
Pulsed Electroacoustic Measurements Of Polymers Irradiated With Low Energy Monoenergetic Electrons, Zachary Gibson, Jr Dennison
Pulsed Electroacoustic Measurements Of Polymers Irradiated With Low Energy Monoenergetic Electrons, Zachary Gibson, Jr Dennison
Physics Student Research
Understanding the dynamics and accumulation of embedded charge in dielectric materials is paramount for many applications from HVDC power transmission to spacecraft charging. The pulsed electroacoustic (PEA) method allows for nondestructive measurements of embedded charge distributions in dielectrics. The spatial resolution of PEA measurements are typically ~10 μm. However, some of the most deleterious spacecraft charging events result from electron fluxes with 10 keV to 50 keV energies, resulting in electron ranges of 1's to 10's of μm. Due to the resolution of the PEA method and the superposition of the interfacial charge with the deposited charge distribution, it is …
Uncertainties Of The Pulsed Electroacoustic Method: Peak Positions Of Embedded Charge Distributions, Zachary Gibson, J. R. Dennison
Uncertainties Of The Pulsed Electroacoustic Method: Peak Positions Of Embedded Charge Distributions, Zachary Gibson, J. R. Dennison
Physics Student Research
The pulsed electroacoustic (PEA) method allows for nondestructive measurements of internal charge distributions in dielectric materials. These measurements have been paramount in understanding and mitigating charge accumulation, aging, and electrostatic discharge in materials for various applications. This study aims to examine more closely the uncertainties of pulsed electroacoustic measurements. The first few moments of a charge distribution are directly related to the magnitude, peak position, full-width-at-half-maximum, and skewness. The uncertainty in the magnitude of the charge distribution is often quite large, but the peak position can be determined with a precision of <1 μm. This has been demonstrated in our lab with repeated PEA measurements of polyether-etherketone (PEEK) with internal charge present. This precision is further validated with measurements of PEEK irradiated with differing doses of 50 keV incident electrons, resulting in peak positions that differ by only a few μm. A final test is given by measurements monitoring the slow migration of the charge distributions in these irradiated samples over several months. The measured shifts in the peak position of the charge distributions are ≤1 μm. Though the spatial resolutions of PEA measurements are typically ~10 μm, as defined by the full- width-at-half-maximum of the leading interfacial peak, the precision of the peak position can be more than an order of magnitude greater. The statistical analysis of the repeated measurements to determine uncertainties, as well as the validation measurements, demonstrate the high precision determination of the peak position of embedded charge distributions.
What Is A Photon? Foundations Of Quantum Field Theory, Charles G. Torre
What Is A Photon? Foundations Of Quantum Field Theory, Charles G. Torre
All Physics Faculty Publications
This is a brief, informal, and relatively low-level course on the foundations of quantum field theory. The prerequisites are undergraduate courses in quantum mechanics and electromagnetism.
Normal-Mode Oscillations For The Circular And Dipolar States Of A Filled Hexagonal Magnetic Dipole Cluster, Peter T. Haugen, Andrew D. P. Smith, Boyd F. Edwards
Normal-Mode Oscillations For The Circular And Dipolar States Of A Filled Hexagonal Magnetic Dipole Cluster, Peter T. Haugen, Andrew D. P. Smith, Boyd F. Edwards
All Physics Faculty Publications
We analyze the rotational dynamics of six magnetic dipoles of identical strength at the vertices of a regular hexagon with a variable-strength dipole in the center. The seven dipoles spin freely about fixed axes that are perpendicular to the plane of the hexagon, with their dipole moments directed parallel to the plane. Equilibrium dipole orientations are calculated as a function of the relative strength of the central dipole. Small-amplitude perturbations about these equilibrium states are calculated in the absence of friction and are compared with analytical results in the limit of zero and infinite central dipole strength. Normal modes and …
Large Earthquakes' Effect On The Ionosphere, Aaron Houston
Large Earthquakes' Effect On The Ionosphere, Aaron Houston
Physics Capstone Projects
The ionosphere is a part of the Earth’s atmosphere that stretches from 80 – 600 kilometers. Gases in this area are ionized which creates a range of free electrons that make up the plasma of the ionosphere. A group of these electrons is known as Total Electron Content (TEC), which is responsible for signal delays between satellites in orbit and their GPS receivers on the surface. Using this delay, the TEC in a specific region can be calculated. This helps in GPS error analysis. During the earthquake in Japan on March 11, 2011, there was allegedly a noticeable jump in …
Improving The Efficiency Of The Preconditioning Of Iterative Solutions To The Kinetic Equation, D. Caleb Price
Improving The Efficiency Of The Preconditioning Of Iterative Solutions To The Kinetic Equation, D. Caleb Price
Physics Capstone Projects
To achieve the reality of fusion, a greater understanding of plasma is required. The kinetic equation can be evolved simultaneously alongside the fluid equations to solve for kinetic closures. NIMROD performs this with numerical solvers where the General Minimum Residual (GMRES) solver becomes more efficient with a preconditioning matrix as input. Using a GPU-enabled library, the efficiency of GPU offloading to the preconditioning step was tested. A significant decrease in the factoring time of preconditioning matrix was observed. This suggests that the allocation of GPUs is worth investigating for NIMROD’s own benefit, but also anyone seeking to improve the efficiency …
Seasonal Variations In Global Ionospheric Total Electron Content, Jason Knudsen
Seasonal Variations In Global Ionospheric Total Electron Content, Jason Knudsen
Physics Capstone Projects
As the Sun ionizes atoms and molecules in the Earth’s ionosphere, the region of atmosphere above approximately 100 km in altitude, the created ionization in this region affects many of the systems that we rely on in daily life. This includes cellular service, GPS navigation, weather forecasting, and credit card data. A good measure for the level of ionization in the ionosphere is total electron content (TEC), which is the number of electrons in a square column above a given geographic location. The TEC over a geographic location influences the propagation of radio waves that traverse that section of the …
Characteristics Of Mesospheric Temperature And Gravity Waves Over Chile In 2020-2021, Damien M. Devitt, Kenneth Zia
Characteristics Of Mesospheric Temperature And Gravity Waves Over Chile In 2020-2021, Damien M. Devitt, Kenneth Zia
Physics Capstone Projects
Gravity waves (GWs) are often confused with gravitational waves in the fabric of space time. However, there is a clear distinction between them. Gravity wave is a term used by the atmospheric research field to describe perturbations in the atmosphere. Gravity pulls the perturbations down and causes oscillations, these present in the form of waves. The best visualization is to think of ripples on a pond, as the ripple reaches its peak gravity pulls the ripple down and creates an oscillating effect.
Modeling The Effects Of Surface Roughness On Electron Yield, Trace Taylor, Matthew Robertson, Jr Dennison
Modeling The Effects Of Surface Roughness On Electron Yield, Trace Taylor, Matthew Robertson, Jr Dennison
Conference Proceedings
Surface conditions—including surface morphology, composition, contamination, and oxidation—can significantly affect electron yields and consequently spacecraft charging. The effects of surface roughness on electron yield are modeled in this study by considering four aspects of electron yield calculations: (i) simple models of rough surface geometry, (ii) the angular distributions of electrons emitted from various points on these surfaces, (iii) the likelihood of these emitted electrons escaping the rough surface, and (iv) the relative fractions of smooth and rough surfaces. Three simple periodic one-dimensional surface profiles were considered—namely rectangular, triangular, and sawtooth features; each surface profile was characterized by an aspect ratio …
Laboratory Simulations Of Simultaneous Reduced Gravity And Ionizing Radiation Environments, Achal Duhoon, Jr Dennison
Laboratory Simulations Of Simultaneous Reduced Gravity And Ionizing Radiation Environments, Achal Duhoon, Jr Dennison
Conference Proceedings
A novel system has been developed to simulate the combined effects of reduced gravity and ionizing radiation present during spaceflight on biological and particulate samples. The miniature rotary cell culture system (mRCCS) was designed to synchronously rotate up to five independent vessels containing particulate samples suspended in fluid media, constructed using radiation tolerant, biocompatible, and vacuum compatible materials. Reduced gravity conditions were achieved when particles (e.g., 200 µm polystyrene microcarrier beads with or without adhered cell clusters) were suspended inside the vessels moving near terminal velocity in viscous fluid media with densities matched to the suspended …
The Relevance Of Pulsed Electroacoustic Measurements For Spacecraft Charging, Zachary Gibson, J. R. Dennison
The Relevance Of Pulsed Electroacoustic Measurements For Spacecraft Charging, Zachary Gibson, J. R. Dennison
Physics Student Research
The magnitude and spatial distribution of charge embedded in dielectric materials and the evolution of the charge distributions with time are at the heart of understanding spacecraft charging. Spacecraft materials are charged primarily by incident fluxes of low energy electrons, with electron fluxes in the 10 keV to 50 keV range often responsible for the largest deleterious arcing effects. While the pulsed electroacoustic (PEA) method can provide sensitive non-destructive measurements of the internal charge distribution in insulating materials, it has often been limited for spacecraft charging applications by typical spatial resolutions of ≤10 μm, with a 10 μm range of …
Utah's Food Processing Industry Can Manufacture Products From Cbd-Containing Lipids That Have Superior Texture And Consistency, Joseph Cooney, Isaac Hilton
Utah's Food Processing Industry Can Manufacture Products From Cbd-Containing Lipids That Have Superior Texture And Consistency, Joseph Cooney, Isaac Hilton
Research on Capitol Hill
Sophomore Joseph is an Honors student and Undergraduate Research Fellow studying physics. Freshman Isaac, of Kaysville, studies civil and environmental engineering. Joseph and Isaac are exploring how cannabinoids impact the way that lipids function. A common way CBD is packaged is within foods, where it is frequently added to fats like cocoa butter or palm oil, and as the market for such products increase producers need to understand CBD will change the behavior of the fats they are using.In addition to this work, Joseph also volunteers for a physics lab. “Undergraduate research has let me explore fields outside my major …
The Surface Conditions Of Spacecraft Panels May Significantly Affect Spacecraft Survivability, Trace Taylor
The Surface Conditions Of Spacecraft Panels May Significantly Affect Spacecraft Survivability, Trace Taylor
Research on Capitol Hill
USU junior Trace grew up in Brigham City and studies physics and electrical engineering. The majority of spacecraft failure is caused by electron charging on the outer surfaces of the craft. Additionally, contaminants on the craft can cause a film over surface panels, increasing the problem. Trace is studying how roughness on panels can mitigate this contamination as it affects the charging that can lead to craft failure. This research will help determine what optimal panel materials should be used in future spacecraft construction. Trace started research almost as soon as he came to campus in his freshman year, and …
Hysteretic Transition Between States Of A Filled Hexagonal Magnetic Dipole Cluster, Andrew D. P. Smith, Peter T. Haugen, Boyd F. Edwards
Hysteretic Transition Between States Of A Filled Hexagonal Magnetic Dipole Cluster, Andrew D. P. Smith, Peter T. Haugen, Boyd F. Edwards
All Physics Faculty Publications
By minimizing the magnetostatic potential energy and by finding zeros in the sum of the squares of the torques, we find the equilibrium states of six dipoles of identical strength at the vertices of a regular hexagon and a variable-strength dipole at the center. The seven dipoles spin freely about fixed axes that are perpendicular to the plane of the hexagon, with their dipole moments directed parallel to the plane. When the central dipole is weak compared with the perimeter dipoles, a ‘‘circular’’ state applies in which the perimeter dipole moments circle around the central dipole, which points toward a …