3,780 research outputs found

    News coverage of manned space missions

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    Problems involved in news coverage of manned space mission

    Application of numerical optimization to the design of wings with specified pressure distributions

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    A practical procedure for the optimum design of transonic wings is demonstrated. The procedure uses an optimization program based on the method of feasible directions coupled with an aerodynamic analysis program which solves the three-dimensional potential equation for subsonic through transonic flow. Two new wings for the A-7 aircraft were designed by using the optimization procedure to achieve specified surface pressure distributions. The new wings, along with the existing A-7 wing, were tested in the Ames 11 ft transonic wind tunnel. The experimental data show that all of the performance goals were met. However, comparisons of the wind tunnel results with the theoretical predictions indicate some differences at conditions for which strong shock waves occur

    The Phosphoramidase Competency of Prototypical Phosphatase Catalytic Motifs

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    The discovery that phosphorylation of proteins occurs on nitrogen by particular kinases raises the question of whether a separate class of phosphoramidases also exists, or if known phosphatases carry out the hydrolysis of phosphoramidates. The phosphoramidase activity of a number of phosphatases with different catalytic motifs was studied using the substrates N-phenylphosphoramidate (N-phPAM) and phosphoryl imidazole (PIm). The phosphatases assayed were: the protein tyrosine phosphatase YopH; alkaline phosphatase; the dual-specificity phosphatase VHR; prostatic acid phosphatase, PAcP; PHPT1, the only known phosphohistidine phosphatase; and, the serine/threonine phosphatases Lambda PP and PP1. The catalytic efficiencies, kcat/KM (s-1M-1), were compared for the respective phosphoramidase and phosphatase activities for each enzyme. Ratios of catalytic efficiencies (kcat/KM)/(kcat/KM) of pNPP over PIm are: YopH - 27; AP - 4.1; VHR - 0.22; PAcP - 1.6; AP - 0.51; and PHPT1 - 0.00007. Lambda PP catalyzed hydrolysis of PIm, although kinetic constants could not be obtained. PP1 exhibited no phosphoramidase activity. The results show that most phosphatase catalytic motifs display catalytic promiscuity by cleaving both phosphoesters and phosphoramidates, but with a pronounced preference for one substrate type versus the other

    Ripple

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    My work leverages the dynamic processes the brain uses to compute visual stimuli to influence how viewers experience my work. My aim is to create a ripple effect as the brain processes the visual information I provide. My process begins with a camera. Focusing on the face, I see how much contextual information I can remove while still capturing the emotional expression of the subject. Before long, a photograph ends up next to a canvas where I will rebuild the image from the photograph using a myriad of expressionistic marks and colors to amplify the emotion. Recognizing human emotion is the first ripple I want the viewer to experience. Next, they will note secondary details about the person depicted. Last, they will notice the heightened textures, the amplified flaws, the abstraction of the mark – reminders that they are looking at nothing more than a medium applied to a two-dimensional surface

    Promissory Note, 30 April 1849

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    https://egrove.olemiss.edu/aldrichcorr_b/1207/thumbnail.jp

    Computational wing optimization and comparisons with experiment for a semi-span wing model

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    A computational wing optimization procedure was developed and verified by an experimental investigation of a semi-span variable camber wing model in the NASA Ames Research Center 14 foot transonic wind tunnel. The Bailey-Ballhaus transonic potential flow analysis and Woodward-Carmichael linear theory codes were linked to Vanderplaats constrained minimization routine to optimize model configurations at several subsonic and transonic design points. The 35 deg swept wing is characterized by multi-segmented leading and trailing edge flaps whose hinge lines are swept relative to the leading and trailing edges of the wing. By varying deflection angles of the flap segments, camber and twist distribution can be optimized for different design conditions. Results indicate that numerical optimization can be both an effective and efficient design tool. The optimized configurations had as good or better lift to drag ratios at the design points as the best designs previously tested during an extensive parametric study

    Index to Volume 22

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