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Dust devils have proven to be commonplace on Mars, although their occurrence is unevenly distributed across the surface. They were imaged or inferred by all six successful landed spacecraft: the Viking 1 and 2 Landers (VL-1 and VL-2), Mars Pathfinder Lander, the Mars Exploration Rovers Spirit and Opportunity, and the Phoenix Mars Lander. Comparisons of dust devil parameters were based on results from optical and meteorological (MET) detection campaigns. Spatial variations were determined based on comparisons of their frequency, morphology, and behavior. The Spirit data spanning three consecutive martian years is used as the basis of comparison because it is the most extensive on this topic. Average diameters were between 8 and 115 m for all observed or detected dust devils. The average horizontal speed for all of the studies was roughly 5 m/s. At each site dust devil densities peaked between 09:00 and 17:00 LTST during the spring and summer seasons supporting insolation-driven convection as the primary formation mechanism. Seasonal number frequency averaged ~1 dust devils/ km2/sol and spanned a total of three orders of magnitude. Extrapolated number frequencies determined for optical campaigns at the Pathfinder and Spirit sites accounted for temporal and spatial inconsistencies and averaged ~19 dust devils/km2/sol. Dust fluxes calculated from Pathfinder data (5x10-4 kg/m2/s and 7x10-5 kg/m2/s) were well with in the ranges calculated from Spirit data (4.0x10-9 to 4.6x10-4 kg/m2/s for Season One, 5.2x10-7 to 6.2x10-5 kg/m2/s during Season Two, and 1.5x10-7 to 1.6x10-4 kg/m2/s during Season Three). Based on the results a campaign is written for improvements in dust devil detection at the Mars Science Laboratory's (MSL) site. Of the four remaining candidate MSL sites, the dusty plains of Gale crater may potentially be the site with the highest probability of dust devil activity.
ContributorsWaller, Devin (Author) / Greeley, Ronald (Thesis advisor) / Christensen, Philip R. (Philip Russel) (Committee member) / Cerveny, Randall (Committee member) / Arizona State University (Publisher)
Created2011
Description
Collaborative learning is a potential technique for teachers to use to meet the diverse learning needs of the students in their classrooms. Previous studies have investigated the contexts in which the benefits of collaborative learning show greater presence. The most important factor found was the quality of the interactions. Studies have suggested that high achieving students are capable of improving the quality of interactions. This bears the question if prior knowledge plays an influence in the learning outcome of students in collaborative learning. Results show that high prior knowledge students do not face a detriment in having low prior knowledge students as a partner comparing to having another high prior knowledge student and that low prior knowledge students show significantly higher learning outcome when partnered with a high prior knowledge partner than with another low prior knowledge student. It is therefore likely that having a high prior knowledge student within a dyad improves the quality of interaction, resulting in greater learning outcome through collaborative learning.
ContributorsKeyvani, Kewmars (Author) / Chi, Michelene (Thesis director) / Wylie, Ruth (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Arizona is a unique state in that rain is not a normal occurrence throughout most of the year (NWS). Arizona averages from less than three months to half a month of measurable precipitation days per year (WRCC). With that, it is important to know the public’s understanding as well as their general trend of likeness towards the weather forecasts they receive. A questionnaire was distributed to 426 people in the state of Arizona to review what they understand from the forecasts and what they would like to see on social media and television.
ContributorsHermansen, Alexis Nicole (Author) / Alvarez, Melanie (Thesis director) / Cerveny, Randall (Committee member) / Hondula, David M. (Committee member) / Walter Cronkite School of Journalism & Mass Comm (Contributor) / School of Geographical Sciences and Urban Planning (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05