9,875 research outputs found

    The GSFC NASTRAN thermal analyzer new capabilities

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    An overview of four analysis capabilities, which developed and integrated into the NASTRAN Thermal Analyzer, is given. To broaden the scope of applications, these additions provide the NTA users with the following capabilities: (1) simulating a thermal louver as a means of the passive thermal control, (2) simulating a fluid loop for transporting energy as a means of the active thermal control, (3) condensing a large sized finite element model for an efficient transient thermal analysis, and (4) entering multiple boundary condition sets in a single submission for execution in steady state thermal analyses

    Subsonic flutter analysis addition to NASTRAN

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    A subsonic flutter analysis capability has been developed for NASTRAN, and a developmental version of the program has been installed on the CDC 6000 series digital computers at the Langley Research Center. The flutter analysis is of the modal type, uses doublet lattice unsteady aerodynamic forces, and solves the flutter equations by using the k-method. Surface and one-dimensional spline functions are used to transform from the aerodynamic degrees of freedom to the structural degrees of freedom. Some preliminary applications of the method to a beamlike wing, a platelike wing, and a platelike wing with a folded tip are compared with existing experimental and analytical results

    Demand Offsets: Water Neutral Development in California

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    NASTRAN cyclic symmetry capability

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    A development for NASTRAN which facilitates the analysis of structures made up of identical segments symmetrically arranged with respect to an axis is described. The key operation in the method is the transformation of the degrees of freedom for the structure into uncoupled symmetrical components, thereby greatly reducing the number of equations which are solved simultaneously. A further reduction occurs if each segment has a plane of reflective symmetry. The only required assumption is that the problem be linear. The capability, as developed, will be available in level 16 of NASTRAN for static stress analysis, steady state heat transfer analysis, and vibration analysis. The paper includes a discussion of the theory, a brief description of the data supplied by the user, and the results obtained for two example problems. The first problem concerns the acoustic modes of a long prismatic cavity imbedded in the propellant grain of a solid rocket motor. The second problem involves the deformations of a large space antenna. The latter example is the first application of the NASTRAN Cyclic Symmetry capability to a really large problem

    Time-Multiplexed Measurements of Nonclassical Light at Telecom Wavelengths

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    We report the experimental reconstruction of the statistical properties of an ultrafast pulsed type-II parametric down conversion source in a periodically poled KTP waveguide at telecom wavelengths, with almost perfect photon-number correlations. We used a photon-number-resolving time-multiplexed detector based on a fiber-optical setup and a pair of avalanche photodiodes. By resorting to a germane data-pattern tomography, we assess the properties of the nonclassical light states states with unprecedented precision.Comment: 4.5 pages, 5 color figues. Comments welcome

    Intravenous versus subcutaneous drug administration. Which do patients prefer? A systematic review

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    BACKGROUND: Intravenous (IV) drug delivery is commonly used for its rapid administration and immediate drug effect. Most studies compare IV to subcutaneous (SC) delivery in terms of safety and efficacy, but little is known about what patients prefer. METHODS: A systematic review was conducted by searching seven electronic databases for articles published up to February 2014. Included studies were randomized controlled trials (RCTs) and/or crossover designs investigating patient preference for SC versus IV administration. The risk of bias in the RCTs was determined using the Cochrane Collaboration tool. Reviewers independently extracted data and assessed the risk of bias. Any discrepancies were resolved by consensus. RESULTS: The search identified 115 publications, but few (6/115) met the inclusion criteria. Patient populations and drugs investigated were diverse. Four of six studies demonstrated a clear patient preference for SC administration. Main factors associated with SC preference were time saving and the ability to have treatment at home. Only three studies used study-specific instruments to measure preference. CONCLUSIONS: Results suggest that patients prefer SC over IV delivery. Patient preference has clearly been neglected in clinical research, but it is important in medical decision making when choosing treatment methods as it has implications for adherence and quality of life. If the safety and efficacy of both administration routes are equivalent, then the most important factor should be patient preference as this will ensure optimal treatment adherence and ultimately improve patient experience or satisfaction. Future drug efficacy and safety studies should include contemporaneous, actual patient preference where possible, utilizing appropriate measures

    Demand Offsets: Water Neutral Development in California

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    Possession of Status Value: An Extension of Status Value Theory

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    Through what mediums is it possible to spread status? Prior research shows that status can be inferred from reward states, status and expectations can spread from one valued characteristic to another, and that differences in the status value of an object possessed by an individual can lead to differences in power during exchange interactions. However, it is not known if possession of these objects actually results in increased status and expectations for an individual possessing the status valued object. Building on Status Value Theory, Status Construction Theory, Reward Expectations Theory, and the Status Value Theory of Power, I construct a theoretical extension to Status Value Theory that proposes that objects are able to temporarily transfer status via possession. In this thesis I lay out the theoretical extension, referred to as the Possession of Status Value Theory, and provide results from an experiment done on Amazon’s Mechanical Turk platform. Results provide partial support for the theory, showing that the status value of objects possess by high status others is acknowledge by future recipients of a status valued object. However, status value transfers only when the participant possesses the high status valued object, and expectations transfer only when their partner is possesses the high status valued object. In addition, low status valued objects seem to have a floor effect for how little status value they contain and how low the expectations individuals have for themselves and others can fall because of possession. The thesis concludes with a discussion of these findings, proposing 3 possible explanations for the results, and future directions for this research

    Regulation of Autotrophic and Heterotrophic Metabolism in Pseudomonas oxalaticus OX1:Growth on Mixtures of Acetate and Formate in Continuous Culture

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    Growth of Pseudomonas oxalaticus in carbon- and energy-limited continuous cultures with mixtures of acetate and formate resulted in the simultaneous utilization of both substrates at all dilution rates tested. During growth on these mixtures, acetate repressed the synthesis of ribulosebisphosphate carboxylase. The degree of this repression was dependent on the dilution rate and on the ratio of acetate and formate in the medium reservoir. At fixed acetate and formate concentrations in the infiowing medium of 30 and 100 mM, respectively, and dilution rates above 0.10 h-1, the severe repression of autotrophic enzymes resulted in a marked increase in bacterial dry weight compared to the growth yield of the organisms on the two substrates separately. Also, at these dilution rates a significant increase in isocitrate lyase activity was observed in the cells as compared to growth on acetate alone. This indicated that under these conditions more acetate was assimilated and less dissimilated since acetate was partly replaced by formate as the energy source. When formate was added to the reservoir of an acetate-limited culture (SR = 30 mM), derepression of RuBPCase synthesis was observed at formate concentrations of 50 mM and above. Below this concentration formate only served as an energy source for acetate assimilation; when its concentration was increased above 50 mM a progressively increasing contribution of carbon dioxide fixation to the total carbon assimilation was observed as the activity of RuBPCase in the cells increased. It is concluded that in Pseudomonas oxalaticus the synthesis of enzymes involved in autotrophic carbon dioxide fixation via the Calvin cycle is regulated by a repression/derepression mechanism
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