Browsing by Subject "space"

Now showing 1 - 3 of 3
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    Complete Hydrogen Storage System by ISRU
    (AIAA, 2018) Schubert, Peter J.; Electrical and Computer Engineering, School of Engineering and Technology
    New technologies make it possible to build in space a complete hydrogen storage system using ISRU methods and techniques. Hydrogen can be stored in a solid-state form on the surface atoms of high surface area matrices such as those of porous silicon. Silicon is abundant in regolith and can be purified using a purely mechanical means which results in particulates in the scale range of tens of nanometers. Reagents used to porosify these nano-particles can be regenerated thermally to essentially eliminate the need for resupply from earth. Catalysts are needed to divide dihydrogen gas into atomic hydrogen for solid-state adsorption and to mediate the temperatures and pressures of charge and discharge into ranges easily achievable with simple equipment. Recent research has identified the utility of non-platinum group catalyst materials which are widespread on the moon. Rapid discharge, needed for propulsion, is possible with infra-red illumination at wavelengths which pass through pure silicon but are absorbed by the silicon-hydrogen bond. Such IR emitters can be fabricated by embossing of silica and additive manufacturing of metals. Control and power electronics can be fabricated using a patented process designed for space operations, and built on either silicon or silicon carbide substrates derived from regolith. Bringing these five technologies together for the first time allows a system which can be fed with moderate pressure gaseous hydrogen at moderate temperatures, stored for long durations with minimum loss, then released upon demand across a wide range of controllable rates. Such a system can displace the need for cryogenic hydrogen storage. Being suitable to bottom-up fabrication using only in-space materials makes this a “green” ISRU technology to store hydrogen for fuel cells, rocket engines, and chemical processes.
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    Postpartum "Fit": Making Space for Feminist Mothering and Mom Bodies in Academic Spaces
    (Journal of Multimodal Rhetorics, 2020) Brooks-Gillies, Marilee; Jorgenson Borchert, Jessica
    Our article discusses how our dress practices have worked to “modify” our bodies as mothers. Eicher (2000) noted how dress practices are actions individuals undertake to modify and supplement the body in order to address physical needs in social spaces. While academic spaces often proclaim “body positivity” out loud (if not in practice), as postpartum academics we sometimes find it hard to embrace body positivity and reconcile the role of mother with our other identity positions. As female Writing Program Administrators (WPAs) of a Writing Center (WC) and a Writing Across the Curriculum (WAC) program respectively, we are keenly aware of our discipline’s “feminized” and “nurturing” identity as something that’s been actively resisted since the feminine is seen as inferior (Grustch McKinney, 2013; Nicholas, 2004). This is particularly true in WCs where “cozy” spaces are cause for distress because “if the writing center is a home and staff is family, that makes the director the mother” (Grutsch McKinney, 2013, p. 26). In other words, presenting as mothers can undermine our identities as serious scholars and administrators. Instead, our article embraces the notion of “feminist mothering” (Miley, 2016; O’Reilly, 2008) and “reclaim our nurturing (mothering) work as empowering, vital work within the institution” (Miley, 2016, p. 2). We contend that the practice of mothering and the bodies of mothers are not impediments to professional spaces and identities. Our article explores the concept of “fit” and examines how our postpartum bodies and our embodied identities and practices as mothers can “fit” in academic spaces. We do not equate our roles as mothers as inferior parts of our identities. We share stories of how we craft our academic personas to negotiate implicit dress codes and embodied norms in academic spaces: sometimes we try to “fit” and other times we stretch the boundaries of those norms recognizing the need for a wider view of what bodies and practices belong in academia.
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    The Staccato Run: A Contemporary Issue in the Zenonian Tradition
    (2000) Burke, Michael B.
    The “staccato run,” in which a runner stops infinitely often while running from one point to another, is a prototype of the “superfeat” (or "supertask”), that is, a feat involving the completion in a finite time of an infinite sequence of distinct, physically individuated acts. There is no widely accepted demonstration that superfeats are impossible logically, but I argue here, contra Grunbaüm, that they are impossible dynamically. Specifically, I show that the staccato run is excluded by Newton’s three laws of motion, when those laws are supplemented with a certain defensible philosophical judgment.