4,661 research outputs found

    ECLSS ORION GFAST

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    Pathway Student Showcase - Environmental Control and Life Support System for Orion Ground and Flight Application Software Tea

    Environmental Control System Development

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    With the ever-growing desire for mankind to reach destinations whose distances had been deemed impossible to transit, the largest rocket known to man was designed and is being developed. The Space Launch System (SLS), National Aeronautics and Space Administrations (NASA) solution for deep space travel, will begin its missions with the launch of Exploration Mission 1 (EM-1) and Exploration Mission 2 (EM-2). In order to accommodate the larger rocket, Kennedy Space Center made crucial upgrades to its existing facilities. At Launch Complex 39B, an entirely new Environmental Control System (ECS) was developed to supply the vehicle with the appropriate air or nitrogen gas mixture for launch. The new ECS displays must undergo Validation and Verification (V&V) using testing procedures developed to meet this requirement

    An algebraic approach to blocking and confounding in factorial arrangements /

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    Syncretic Immersion: Tolkien’s Languages As History, Artifacts, And Meta-Narratives

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    J.R.R. Tolkien’s Middle-earth has been dissected and researched by philologists, medievalists, and literary theorists for decades. Though his work with languages (both historical and invented) has garnered attention over the past few decades, few scholars have looked at his languages in terms of their rhetorical functions within the narrative (as history), with the narrative (as artifacts), and without (as cultural participation). Mark Wolf’s theories on immersion is applied to Tolkien’s legendarium and illuminates his works as uniquely fixated in several modes of immersion at once. Narrative immersion is utilized to understand Tolkien’s works as a furthering of cultural values, languages, and traditions. As these elements of narrative are explored, Tolkien’s legendarium can be seen through conceptual, perceptual, and physical lenses, culminating into a syncretically immersive experience

    Deinococcus radiodurans RNA ligase exemplifies a novel ligase clade with a distinctive N-terminal module that is important for 5′-PO(4) nick sealing and ligase adenylylation but dispensable for phosphodiester formation at an adenylylated nick

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    Deinococcus radiodurans RNA ligase (DraRnl) is a template-directed ligase that seals nicked duplexes in which the 3′-OH strand is RNA. DraRnl is a 342 amino acid polypeptide composed of a C-terminal adenylyltransferase domain fused to a distinctive 126 amino acid N-terminal module (a putative OB-fold). An alanine scan of the C domain identified 9 amino acids essential for nick ligation, which are located within nucleotidyltransferase motifs I, Ia, III, IIIa, IV and V. Seven mutants were dysfunctional by virtue of defects in ligase adenylylation: T163A, H167A, G168A, K186A, E230A, F281A and E305A. Four of these were also defective in phosphodiester formation at a preadenylylated nick: G168A, E230A, F281A and E305A. Two nick sealing-defective mutants were active in ligase adenylylation and sealing a preadenylylated nick, thereby implicating Ser185 and Lys326 in transfer of AMP from the enzyme to the nick 5′-PO(4). Whereas deletion of the N-terminal domain suppressed overall nick ligation and ligase adenylylation, it did not compromise sealing at a preadenylylated nick. Mutational analysis of 15 residues of the N domain identified Lys26, Gln31 and Arg79 as key constituents. Structure–activity relationships at the essential residues were determined via conservative substitutions. We propose that DraRnl typifies a new clade of polynucleotide ligases. DraRnl homologs are detected in several eukaryal proteomes

    Collisional Stripping and Disruption of Super-Earths

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    The final stage of planet formation is dominated by collisions between planetary embryos. The dynamics of this stage determine the orbital configuration and the mass and composition of planets in the system. In the solar system, late giant impacts have been proposed for Mercury, Earth, Mars, and Pluto. In the case of Mercury, this giant impact may have significantly altered the bulk composition of the planet. Here we present the results of smoothed particle hydrodynamics simulations of high-velocity (up to ~5 v_esc) collisions between 1 and 10 M_Earth planets of initially terrestrial composition to investigate the end stages of formation of extrasolar super-Earths. As found in previous simulations of collisions between smaller bodies, when collision energies exceed simple merging, giant impacts are divided into two regimes: (1) disruption and (2) hit-and-run (a grazing inelastic collision and projectile escape). Disruption occurs when the impact parameter is near zero, when the projectile mass is small compared to the target, or at extremely high velocities. In the disruption regime, we derive the criteria for catastrophic disruption (when half the total colliding mass is lost), the transition energy between accretion and erosion, and a scaling law for the change in bulk composition (iron-to-silicate ratio) resulting from collisional stripping of a mantle.Comment: 10 pages, 1 table, 4 figures. Accepted for publication in ApJ Letter

    Artificial scaling laws of the dynamical magnetic susceptibility in heavy-fermion systems

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    We report here how artificial, thus erroneous, scaling laws of the dynamical magnetic susceptibility can be obtained when data are not treated carefully. We consider the example of the heavy-fermion system Ce0.925_{0.925}La0.075_{0.075}Ru2_{2}Si2_{2} and we explain how different kinds of artificial scaling laws in E/TβE/T^\beta can be plotted in a low temperature regime where the dynamical susceptibility is nearly temperature independent.Comment: 4 pages, 4 figure
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