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Physical Sciences and Mathematics Commons™
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Articles 1 - 3 of 3
Full-Text Articles in Physical Sciences and Mathematics
Algebraic Computing Tools In General Relativity: Energy-Momentum Tensors And Exact Solutions To The Einstein Field Equations, Sydney Joanne Chamberlin
Algebraic Computing Tools In General Relativity: Energy-Momentum Tensors And Exact Solutions To The Einstein Field Equations, Sydney Joanne Chamberlin
Undergraduate Honors Capstone Projects
Maple is a mathematical software program containing packages of tools that may be used in making difficult computations. The Tensor sub-package of Maple's Differential Geometry package is a collection of commands used for making tensor computations on manifolds. We present a series of new tools for the Tensor package. Included with these tools are new commands to compute objects of geometric and physical interest -energy-momentum tensors, matter field equations, the Bel-Robinson tensor, etc. -along with tools to compute the geometric properties of these objects. Additionally, an electronic database of exact solutions to the Einstein field equations has been created for …
Polar Mesospheric Clouds: A Satellite And Ground-Based Comparison, Jodie Barker-Tvedtnes
Polar Mesospheric Clouds: A Satellite And Ground-Based Comparison, Jodie Barker-Tvedtnes
Undergraduate Honors Capstone Projects
Polar Mesospheric Clouds (PMCs) are tenuous ice clouds that form near the cold (<150K) summer mesopause region (80-85 km). From the ground, these clouds are seen during twilight hours as Noctilucent or “night shining” Clouds (NLCs) and are typically seen from latitudes from 50° to 65°. Observations by the Solar Backscatter Ultraviolet (SBUV) instruments on the NOAA satellites have shown that the occurrence and brightness of NLCs have been increasing over the last three decades prompting speculation concerning their possible role in climate change. Recently the Aeronomy of Ice in the Mesosphere (AIM) satellite was launched (April 2007) and is the first satellite dedicated to the study of NLCs. In this report, we compare SBUV and AIM PMC observations with ground-based image data collected during two campaigns from Edmonton, Canada (June 30-July 17, 2007) and Delta Junction, Alaska (July 29-August 17, 2007). Four nights of data are discussed where coincident measurements were obtained by AIM, SBUV/2 and ground-based imagers. The results show good spatial or temporal agreement, but rarely both, and illustrate the importance of coordinated measurements for better understanding the geographic and local time variability of PMCs. Initial studies using data from the Ozone Monitoring Instrument (OMI) on the AURA satellite are also presented.
Electrostatic Discharge In Spacecraft Materials, Jennifer Albretsen Roth
Electrostatic Discharge In Spacecraft Materials, Jennifer Albretsen Roth
Undergraduate Honors Capstone Projects
Understanding the characteristics of electron beam bombardment that induce electrostatic discharge (ESD) of insulating materials is crucial to constructing an electrically stable spacecraft. A measurement system has been designed to determine the beam energy and charge flux densities at which typical spacecraft materials intended for the James Webb Space Telescope (JWST) undergo ESD. Because discharge events occur over time intervals ranging from nanoseconds to minutes, multiple detection methods were employed as charge was accumulated on a sample surface; these methods included monitoring of sample current and optical emissions from the sample surface. Each sample was also examined with optical microscopy …