Barrett, The Honors College Thesis/Creative Project Collection
Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.
Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.
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- Creators: School of Earth and Space Exploration
Description
We model the self-compression of homogeneous, undifferentiated, Ceres-like bodies composed of various minerals and mineral-composites: antigorite, brucite, dolomite, lizardite and magnesite, plus mixtures which were the above minerals mixed with ice Ih. All of the modeled clay/ice bodies had a final radius within 1% of RCeres, an average final density of ~2083 kg m-3 and central pressures of ~133 MPa. The smallest radius was from magnesite, which had a final compressed radius of ~0.88 RCeres, central pressure of ~212 MPa and final density of ~2955 kg m-3. The most significant change in radius was due to the zero-pressure density as the highest densities created the highest force of gravity and produced the smallest radii, yet zero-pressure densities that matched Ceres produced 0.99 RCeres bodies. It was found that the addition of ice, anywhere from 9.1-19.1%, did not affect the body a measurable amount as the inclusion of ice resulted in a lower density creating a lower force of gravity, decreased central pressure and less overall compression. Models that closely resembled Ceres had internal pressures of 133 MPa, which is not enough pressure to induce pore collapse or produce drastic changes due to K and K'. Porosity and the addition of ice in Ceres-like bodies is possible and cannot be ignored when using more complicated modeling techniques. Each mineral and mineral-composite produced unique overall results which allowed us to compare each mineral to Ceres, understand how it has compressed over time and how objects of such a size are affected by compression. Due to the small size, low force of gravity and high bulk moduli of the given minerals, Ceres-like bodies do not compress a considerable amount if they are in fact composed of hydrated silicates.
ContributorsMastrean, Alex Travis (Author) / Desch, Steven (Thesis director) / Zolotov, Mikhail (Committee member) / Shim, Sang-Heon Dan (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
This project focuses on using Neutral Gas and Ion Mass Spectrometer (NGIMS) density data for carbon dioxide, oxygen, carbon monoxide, and nitrogen during deep dip campaigns 5, 6, and 8. Density profiles obtained from NGIMS were plotted against simulated density profiles from the Mars Global Ionosphere-Thermosphere Model (MGITM). Averaged temperature profiles were also plotted for the three deep dip campaigns, using NGIMS data and MGITM output. MGITM was also used as a tool to uncover potential heat balance terms needed to reproduce the mean density and temperature profiles measured by NGIMS.
This method of using NGIMS data as a validation tool for MGITM simulations has been tested previously using dayside data from deep dip campaigns 2 and 8. In those cases, MGITM was able to accurately reproduce the measured density and temperature profiles; however, in the deep dip 5 and 6 campaigns, the results are not quite the same, due to the highly variable nature of the nightside thermosphere. MGITM was able to fairly accurately reproduce the density and temperature profiles for deep dip 5, but the deep dip 6 model output showed unexpected significant variation. The deep dip 6 results reveal possible changes to be made to MGITM to more accurately reflect the observed structure of the nighttime thermosphere. In particular, upgrading the model to incorporate a suitable gravity wave parameterization should better capture the role of global winds in maintaining the nighttime thermospheric structure.
This project reveals that there still exist many unknowns about the structure and dynamics of the night side of the Martian atmosphere, as well as significant diurnal variations in density. Further study is needed to uncover these unknowns and their role in atmospheric mass loss.
This method of using NGIMS data as a validation tool for MGITM simulations has been tested previously using dayside data from deep dip campaigns 2 and 8. In those cases, MGITM was able to accurately reproduce the measured density and temperature profiles; however, in the deep dip 5 and 6 campaigns, the results are not quite the same, due to the highly variable nature of the nightside thermosphere. MGITM was able to fairly accurately reproduce the density and temperature profiles for deep dip 5, but the deep dip 6 model output showed unexpected significant variation. The deep dip 6 results reveal possible changes to be made to MGITM to more accurately reflect the observed structure of the nighttime thermosphere. In particular, upgrading the model to incorporate a suitable gravity wave parameterization should better capture the role of global winds in maintaining the nighttime thermospheric structure.
This project reveals that there still exist many unknowns about the structure and dynamics of the night side of the Martian atmosphere, as well as significant diurnal variations in density. Further study is needed to uncover these unknowns and their role in atmospheric mass loss.
ContributorsRobinson, Jenna (Author) / Desch, Steven (Thesis director) / Hervig, Richard (Committee member) / School of Earth and Space Exploration (Contributor) / School for the Future of Innovation in Society (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05