Matching Items (128)
Description
The lunar poles have hydrated materials in their permanently shadowed regions (PSRs), also known as lunar cold traps. These cold traps exist because of the Moon’s slight tilt of 1.5, which consequently creates these PSRs. In these shadows, the temperature remains cold enough to prevent the sublimation of volatile materials for timescales spanning that of geologic times [Hayne et. al 2015]. PSRs are significant because they create an environment where water ice can exist within the first meter of regolith at the lunar poles, where many cold traps are present. These volatile materials can be observed through a process called neutron spectroscopy. Neutron spectroscopy is a method of observing the neutron interactions caused by galactic and extragalactic cosmic ray proton collisions. Neutron interactions are more sensitive to hydrogen than other elements found in the regolith, and thus are a good indicator of hydrated materials. Using neutron spectroscopy, it is possible to detect the hydrogen in these cold traps up to a meter deep in the regolith, thus detecting the presence of hydrated materials, water, or ice.
For this study, we used the Monte Carlo Neutral Particle Transport Code (MCNP6) to create a homogenous sphere that represented the PSRs on Moon, and then modeled five differing water contents for the lunar regolith ranging from 0-20 percent weight. These percent weights were modeled after the estimates for Shackleton crater, data from Lunar Reconnaissance Orbiter (LRO) mission, and data from Lunar Orbiter Laser Altimeter (LOLA).
This study was created with the LunaH-Map mission as motivation, seeking to exhibit what neutron data might be observed. The LunaH-Map mission is an array of mini-Neutron Spectrometers that will orbit the Moon 8-20 km away from the lunar surface and map the spatial
distribution of hydrogen at the lunar poles. The plots generated show the relationship between neutron flux and energy from the surface of the Moon as well as from 10km away. This data provides insight into the benefits of collecting orbital data versus surface data, as well as illustrating what LunaH-Map might observe within a PSR.
For this study, we used the Monte Carlo Neutral Particle Transport Code (MCNP6) to create a homogenous sphere that represented the PSRs on Moon, and then modeled five differing water contents for the lunar regolith ranging from 0-20 percent weight. These percent weights were modeled after the estimates for Shackleton crater, data from Lunar Reconnaissance Orbiter (LRO) mission, and data from Lunar Orbiter Laser Altimeter (LOLA).
This study was created with the LunaH-Map mission as motivation, seeking to exhibit what neutron data might be observed. The LunaH-Map mission is an array of mini-Neutron Spectrometers that will orbit the Moon 8-20 km away from the lunar surface and map the spatial
distribution of hydrogen at the lunar poles. The plots generated show the relationship between neutron flux and energy from the surface of the Moon as well as from 10km away. This data provides insight into the benefits of collecting orbital data versus surface data, as well as illustrating what LunaH-Map might observe within a PSR.
ContributorsEttenborough, Ivy E (Author) / Hardgrove, Craig (Thesis director) / Wadhwa, Meenakshi (Committee member) / Czarnecki, Sean (Committee member) / School of Earth and Space Exploration (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The mountains of western North America are spectacular and diverse, from sheer walls of crumbling black limestone in the Canadian Rockies, to smooth glacially polished granite in the Wind River Range, to gargantuan ice-clad volcanoes in the Cascades. These great bastions of rock, snow, and ice, still very much wild and untamed, provide an incredible arena for adventure, exploration, and challenge. Over the past three years, I have devoted thousands of hours to exploring these vast wild places, climbing high peaks, steep cliffs, and frozen waterfalls. In doing so, I studied the rich geologic history of the mountains. This thesis project is a compilation of stories and images from those adventures, along with the stories of the mountains themselves: how the rocks were formed, thrust skyward, and sculpted over the ages into their present, glorious form. The photographic and detailed narrative of the geology and adventures is on a new website called Cloud Piercers, which currently features three geologically diverse mountain massifs: (1) Mount Rainier, an active volcano in the Cascade Range of Washington; (2) Mount Robson, the highest peak in the Canadian Rockies, within a terrain of folded Paleozoic sedimentary rocks; and (3) the Wind River Range of Wyoming, composed mostly of Archean metamorphic and granitic rocks. This website will be expanded in the future as the geologic studies and adventures continue.
ContributorsSteadman, Dane Kyle (Author) / Reynolds, Stephen (Thesis director) / Johnson, Julia (Committee member) / Heimsath, Arjun (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Ion channels in the membranes of cells in the body allow for the creation of action potentials from external stimuli, allowing us to sense our surroundings. One particular channel, TRPM8, is a trans-membrane ion channel believed to be the primary cold sensor in humans. Despite this important biological role and intense study of the channel, TRPM8 is not fully understood mechanistically and has not been accurately modeled. Existing models of TRPM8 fail to account for menthol activation of the channel. In this paper we re-implement an established whole cell model for TRPM8 with gating by both voltage and temperature. Using experimental data obtained from the Van Horn lab at Arizona State University, we refined the model to represent more accurately the dynamics of the human TRPM8 channel and incorporate the channel activation through menthol agonist binding. Our new model provides a large improvement over preexisting models, and serves as a basis for future incorporation of other channel activators of TRPM8 and for the modeling of other channels in the TRP family.
ContributorsAckerman, David (Author) / Crook, Sharon (Thesis director) / Van Horn, Wade (Committee member) / School of Earth and Space Exploration (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This study was conducted in order to determine whether the lagomorphs of 111 Ranch- Aztlanolagus agilis, Hypolagus arizonensis, and Sylvilagus cunicularius- could be distinguished based on femora. This is because while there is a large quantity of disarticulated lagomorph postcranial fossils from 111 Ranch, the chief diagnostic traits of A. agilis and H. arizonensis are the enamel patterns on their third premolars, leaving a large swath of specimens unidentifiable by diagnostic traits alone. Specimens from the Arizona Museum of Natural History were measured and compared to specimens known to be from these genera. Additionally, morphological traits in mandibles were used to identify mandible specimens, which in turn were used to identify fossils with the same specimen label. Statistical tests such as t-tests and principal components analyses were used to examine the distributions of sizes and locate clusters of datapoints likely corresponding to each genus. Some of these could be linked to a genus based on one particular specimen, P15156, which had been identified as Hypolagus based on its mandible morphology and size. The majority of the Museum'a specimens were thus associated with one of the three species, save for those which were too damaged and intermediate in size to confidently categorize.
ContributorsTkacik, Stephanie Marie (Author) / Farmer, Jack (Thesis director) / Reed, Kaye (Committee member) / McCord, Robert (Committee member) / School of Earth and Space Exploration (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The Hydrogen Epoch of Reionization Array, HERA, is a radio telescope currently being built in South Africa that plans to observe the early universe, specifically the earliest period of star and galaxy formation. It plans to use a tool called a delay spectrum to separate signal emitted from this time from the much brighter radio foregrounds. It is the purpose of this paper to outline the method used to characterize the contamination of these delay spectra by bright emissions of radio here on Earth called radio frequency interference, RFI. The portion of the bandwidth containing the signal from the period of initial star formation was specifically examined. In order to receive usable data, the HERA commissioning team was assisted in the evaluation of the most recent data releases. On the first batch of usable data, flagging algorithms were run in order to mask all of the RFI present. A method of filling these masked values was determined, which allowed for the delay spectrum to be observed. Various methods of injecting RFI into the data were tested which portrayed the large dependence of the delay spectrum on its presence. Finally, the noise power was estimated in order to predict whether or not the limitations observed in the dynamic range were comparable to the noise floor. By examining the evolution of the delay spectrum's power as a range of noise power was introduced, there is a good amount of evidence that this limitation is in fact the noise floor. From this, we see that excision algorithms and interpolation used are capable of removing the effects of most all of the RFI contamination.
ContributorsBechtel, Shane Kirkpatrick (Author) / Bowman, Judd (Thesis director) / Jacobs, Daniel (Committee member) / Beardsley, Adam (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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
Description
The purpose of this paper is to explore the historical development of Native Americans' participation in public lands management. The literature on federal-tribal relations in public lands management demonstrates that Native Americans face an uphill battle in order to receive recognition of and protection for their cultural and traditional ties to public lands. This paper uses Arnstein's ladder of participation to evaluate several historical examples of federal-tribal relations in public lands management. Arnstein's ladder of participation shows how different forms of participation correspond to an individual or groups power to affect outcomes of decision-making processes. The examples discussed in this paper are explicative of these different forms of participation and show that the predominance of hierarchical power structures and particular cultural ideals of American society have impeded recognition of and protection for Native Americans' cultural and traditional ties to public lands. Around the end of the 19th century and start of the 20th century, forms of nonparticipation excluded Native Americans from the emerging dialogue concerning the nation's first public lands. Although Native Americans became more militant and assertive in the economic, political, and cultural spheres of American society as time went on, tokenistic forms of participation still precluded effective and equitable recognition of and protection for their cultural and traditional ties to public lands. This paper concludes with an evaluation of the recent creation of Bears Ears National Monument by presidential proclamation and how the organization and activism by several tribes to receive protection for the Bears Ears landscape demonstrates the potential for similar approaches to produce more effective and equitable forms of participation.
ContributorsScott, Cameron (Author) / Kelley, Jason (Thesis director) / Pijawka, David (Committee member) / School of Earth and Space Exploration (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Two large sectors of water consumption within cities are: city owned irrigated landscape (such as parks) and household consumption. A related, third sector of consumption that has very little research behind it is shared landscapes in residential communities. Neighborhood communities, including those with formal Homeowner’s Associations and informal Neighborhood Associations, have common landscapes they are responsible for up-keeping and irrigating. 208 neighborhood communities exist within the City of Tempe. Each year the city provides $30,000 in grant funding to these 208 neighborhoods to implement water conservation projects. This thesis focuses on ten neighborhoods who had applied and were granted funding to implement a conservation project between the years 2011 and 2016. My findings showed that this program has not been effective in reducing water consumption, wither due to the lack of implementation or the small-scale of the projects. From my research and synthesis, I suggest a layer of accountability be added to the program to ensure projects are effective and participants are implementing their projects and that the program is effective overall. This study provides the City of Tempe with relevant and viable information to aid management of water consumption and conservation within neighborhoods.
ContributorsApillanes, Sierra Caitlyn (Author) / Larson, Kelli (Thesis director) / Bomar, Melissa (Committee member) / School of Sustainability (Contributor, Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Time travel is closely associated with futuristic science fiction, but it is a concept that dates back to ancient times. Over many generations it has been developed and explored narratively and scientifically. This paper aims to document and analyze the history of the time travel concept and the important role fiction had in its development.
ContributorsElkins, Sydney (Author) / Foy, Joseph (Thesis director) / Maynard, Andrew (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
Western culture has oversimplified and mythologized the possibility of first contact with extraterrestrial intelligence. Whether through anthropocentrism, lack of contextual literature and/or available knowledge, or simple misunderstanding, humanity has failed to fully consider the impacts of seeking out alien life. Instead, humanity’s cultural and political representations of extraterrestrials tell us a great deal about the people behind the stories—all of us stuck together on our pale blue dot. This thesis explores the mythological character that is ever-present in the extraterrestrial conversation, and how past and current cultural creators in the global West have perpetuated and changed that paradigm. This thesis is also an exploration of the ways we envision our ability to contact and interact with an unknown extraterrestrial other—in many ways mythological, and in some ways as powerful symbols for struggles against oppression. I argue for a more nuanced, creative, and scientifically driven representation and consideration of first contact with extraterrestrial intelligence.
ContributorsDean, Jake William (Author) / Martin, Thomas W. (Thesis director) / Walker, Sara (Committee member) / Finn, Ed (Committee member) / Historical, Philosophical & Religious Studies (Contributor, Contributor) / School of Earth and Space Exploration (Contributor) / School of Sustainability (Contributor, Contributor, Contributor) / School of Human Evolution & Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12