Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
Articles 1 - 4 of 4
Full-Text Articles in Physics
Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown
Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown
STAR Program Research Presentations
Astrophysicists use radiation to investigate the physics controlling a variety of celestial sources, including stellar atmospheres, black holes, and binary systems. By measuring the spectrum of the emitted radiation, astrophysicists can determine a source’s temperature and composition. Accurate atomic data are needed for reliably interpreting these spectra. Here we present an overview of how LLNL’s EBIT facility is used to put the atomic data on sound footing for use by the high energy astrophysics community.
The Study Of Variability In Oxygen-Rich Proto-Planetary Nebulae, Kristie Shaw
The Study Of Variability In Oxygen-Rich Proto-Planetary Nebulae, Kristie Shaw
Symposium on Undergraduate Research and Creative Expression (SOURCE)
In this project, I am studying and analyzing the light and color variations for two proto-planetary nebulae (PPNe). PPNe is a stage in a star’s life where the star is in the process of losing its outer layers and exposing its core. I observed at the Valparaiso University Observatory, using the 0.4 meter telescope and an electronic camera to take digital images. I reduced these data using an image processing program to get the numerical data results. I plotted these results as a light curve showing the variation in brightness of the star versus time. By observing in three different …
The Effect Of Strong Electrostatic And Magnetostatic Fields On The Activity Of Radioactive Nuclides, Sam Schaub
The Effect Of Strong Electrostatic And Magnetostatic Fields On The Activity Of Radioactive Nuclides, Sam Schaub
Symposium on Undergraduate Research and Creative Expression (SOURCE)
This experiment seeks to measure the effect of strong electrostatic and magnetostatic fields on the decay constant of short-lived radioactive isotopes. Though it is assumed in modern radioactivity theory that such fields should not have any measurable effect, conclusive evidence utilizing modern equipment is absent from published literature. Samples have been monitored that exhibit beta-minus, beta-plus, electron capture, and internal conversion modes of radioactive decay. Radioactive nuclides chosen for this study include I-128, Cs-134, and Cu-64. The half-lives in this collection of radioactive nuclides range from 25 minutes to 12.7 hours. Sodium Iodide detectors are used to monitor the samples …
Diffusive Transport Enhanced By Thermal Velocity Fluctuations, Alejandro Garcia, A. Donev, A. De La Fuente, J. B. Bell
Diffusive Transport Enhanced By Thermal Velocity Fluctuations, Alejandro Garcia, A. Donev, A. De La Fuente, J. B. Bell
Faculty Publications
We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. We find good agreement between a simple fluctuating hydrodynamics theory and particle and finite-volume simulations. The enhancement of the diffusive transport depends on the system size L and grows as ln(L/L0) in quasi-two-dimensional systems, while in three dimensions it scales as L0-1-L-1, where L0 is a reference length. Our results demonstrate that fluctuations play an important role in the hydrodynamics of small-scale systems.