The Flux of Impact Ejecta on the Lunar Surface from Scaling Considerations: Implications for Operational Hazards and Geomorphic Forcing

The impact cratering process has been critical to the evolution of the Moons surface over its geologic history and remains an important ongoing process today. Impact events have a major local effect, but also excavate ejecta particles that re-impact the lunar surface over a wide area. Quantifying the flux of ejecta to a given point on the Moon is the subject of this work. We also estimate how this flux is partitioned into different particle sizes and different ejecta velocities. Motivation: There are two main factors motivating this work. First, and most critically, is the assessment of the hazard posed by impact ejecta for future surface exploration (i.e., to infrastructure, spacesuits, etc.). LROC observations of new craters have led to the reemphasized need to consider this hazard. In fact, a hazard assessment of this type was made prior to Apollo, although some of the underlying assumptions of that work are now clearly obsolete (see [4]). We also now know much more about the impactor flux, scaling of impact events, and scaling of ejecta than was known in the 1960's, so revisiting this hazard assessment is appropriate.We note that also have recently revisited the earlier hazard estimates and independently revised them downward using an entirely different analytical approach. The second motivation is that several recent papers have argued that the flux of distal ejecta is the controlling factor in how fast the lunar surface evolves. For this reason, improving understanding of the ejecta mass flux and how the flux translates into geomorphic work is of interest. To be clear, it is obvious that the ejecta mass flux is much larger than the primary impactor mass flux indeed, this is self-evident because the craters excavated by hypervelocity impacts are much larger than their impactors. On the other hand, the energy delivered by a given primary to the surface is larger than the sum of the energy delivered by all its associated ejecta, as required by conservation, aggravated by the fact that not all of an impactors kinetic energy is partitioned into ejecta excavation. If distal ejecta and secondaries control lunar geomorphic evolution, this suggests that re-impacting ejecta must more efficiently translate their energy into geomorphic work than primaries. It is also easy to imagine the relative efficiency of primary and secondary impacts to do geomorphic work varying with the size of the primary. Considering the details of this process is thus of significant interest for lunar geomorphology

Violence and Edification in 19th Century Fiction: An Analysis of the Novels of Charles Dickens and Leo Tolstoy

This Thesis argues that violence is essential to the structures and plots of Charles Dickens’s Barnaby Rudge and A Tale of Two Cities and of Leo Tolstoy’s War and Peace and Anna Karenina, and is particularly essential to the edification, or the moral and intellectual improvement, of principal characters in these four novels. Additionally, this Thesis contends that this edification is both anticipated and reinforced by the novelists’ incorporation of counterparts whose demeanor and/or narrative overtly mirror that of the principal characters. To support this argument, I bring the theory of Thomas Carlyle into conversation with the novels of Dickens to illuminate Dickens\u27s perceptions of heroism and hero-worship, and how these perceptions influence the plot and characters of his novels. Specifically, I argue that Dickens shapes his edified characters to align with Carlyle\u27s delineation of sincere heroes, rejects Carlyle\u27s belief in the boundlessness and thoughtlessness of hero-worship, and engages with his interest in the heroic psyche to effectively underscore the moral and intellectual enlightenment of both Barnaby Rudge of Barnaby Rudge and Sydney Carton of A Tale of Two Cities. Additionally, I bring the theory of Jean-Jacques Rousseau into conversation with Tolstoy to illustrate how the relationships between society and war and between virtue and the soldierly profession function within his novels. Particularly, I argue that societal forces compel Prince Andrey Bolkonsky and Count Pierre Bezukhov of War and Peace, as well as Alexei Vronsky of Anna Karenina, to become soldiers. Additionally, I contend that Tolstoy portrays the martial profession in a virtuous light in order to foreshadow the edification of Andrey and Pierre, who are morally and intellectually improved in character after entering the world of war, as well as the non-edification of Alexei Vronsky, who eschews the war effort in order to pursue a hedonistic affair with the married Anna Karenina. In writing this Thesis, I seek to eviscerate commonly shared notions of violence as a concept that carries solely negative connotations, or as a tool injected into novels for superficial or simplistic reasons. In rejecting these notions, I not only substantiate the complexity of the function of violence in fiction, but also the life-affirming spirit of the novels that I have chosen to analyze

Wyoming’s New Instream Flow Law

28 pages. Contains references

Big Horn River Litigation Experience: The Second Generation – Post Decree Administration

5 pages

On Defining At-Risk: The Role of Educational Ritual in Constructions of Success and Failure

By adopting an ethnomethodological approach to the analysis of focus group interviews with undergraduate students enrolled in and teachers of the introductory course in speech communication, this essay demonstrates that we understand to be a stable, objective aspect of reality--i.e., the inevitability of educational failure--is in fact a human accomplishment, the result of concerted, through unreflective, social action. This paper explores the ways in which students\u27 and graduate teaching assistants\u27 espousal of educational rituals may create and sustain their (or their students\u27) risk of educational failure. Futhermore, the implications of such a perspective for graduate teaching assistants of the basic courses are examined

Big Horn River Litigation Experience: The Second Generation – Post Decree Administration

5 pages

Beyond \u27Basic\u27: Opportunities for Relevance

Recently one of my colleagues asked me if I could foresee a time when I would give up supervising teaching associates; she said it in a kindly way, but with a cringe and a shrug, as if to suggest that I was sacrificing my efforts on something beneath me…a departmental service. I’ve been coordinating our introductory public speaking course and supervising TAs for fourteen years now, and I still get this question. Each time, I explain that giving up those responsibilities would be like asking someone to uproot their research passion from, say, performance studies to instructional communication, from any old this to any old that. The question implies that the work I do to nurture, sustain and strengthen the introductory course is a labor. I would contend that our work with the “basic” course is more a labor of love, but, as with all labors of love, we undervalue our efforts

The Science Case for Caching and Returning Samples from Jezero Crater, Mars

No abstract availabl