4,496 research outputs found

    Evaluation of circumferential airflow uniformity entering combustors from compressors. Volume 2: Data supplement

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    A study of the airflow uniformity leaving compressors and entering combustors was made using compressors from two advanced engines, the J58 and F100/F401. The data used in the analysis of each case is presented in tabular form and computer-generated profile plots. A plot of the square root of the dynamic pressure ratio, which is similar to airflow deviation, is also presented

    Foreign direct investment and inequality in developing countries: does sector matter?

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    Scholars have studied the relationship between inward foreign direct investment (FDI) and within-country income inequality in cross-national contexts, but have not empirically investigated how FDI in different sectors might affect inequality in different ways. We use error correction models to analyze sectoral FDI data compiled from UNCTAD investment reports in 41 middle-income countries from 1989 to 2010, arguing that FDI in services is more likely to be associated with inequality than FDI in other sectors. We argue that skill biases and changes in employment patterns associated with service sector investments can help explain these findings

    Tuning Fermi-surface properties through quantum confinement in metallic meta-lattices: New metals from old atoms

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    We describe a new class of nanoscale structured metals wherein the effects of quantum confinement are combined with dispersive metallic electronic states to induce modifications to the fundamental low-energy microscopic properties of a three-dimensional metal: the density of states, the distribution of Fermi velocities, and the collective electronic response.Comment: 4 pages, 5 figures, to appear in Phys. Rev. Let

    Asymptotics of 10j symbols

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    The Riemannian 10j symbols are spin networks that assign an amplitude to each 4-simplex in the Barrett-Crane model of Riemannian quantum gravity. This amplitude is a function of the areas of the 10 faces of the 4-simplex, and Barrett and Williams have shown that one contribution to its asymptotics comes from the Regge action for all non-degenerate 4-simplices with the specified face areas. However, we show numerically that the dominant contribution comes from degenerate 4-simplices. As a consequence, one can compute the asymptotics of the Riemannian 10j symbols by evaluating a `degenerate spin network', where the rotation group SO(4) is replaced by the Euclidean group of isometries of R^3. We conjecture formulas for the asymptotics of a large class of Riemannian and Lorentzian spin networks in terms of these degenerate spin networks, and check these formulas in some special cases. Among other things, this conjecture implies that the Lorentzian 10j symbols are asymptotic to 1/16 times the Riemannian ones.Comment: 25 pages LaTeX with 8 encapsulated Postscript figures. v2 has various clarifications and better page breaks. v3 is the final version, to appear in Classical and Quantum Gravity, and has a few minor corrections and additional reference

    The Arecibo Methanol Maser Galactic Plane Survey - II: Statistical and Multi-wavelength Counterpart Analysis

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    We present an analysis of the properties of the 6.7 GHz methanol maser sample detected in the Arecibo Methanol Maser Galactic Plane Survey. The distribution of the masers in the Galaxy, and statistics of their multi-wavelength counterparts is consistent with the hypothesis of 6.7 GHz maser emission being associated with massive young stellar objects. Using the detection statistics of our survey, we estimate the minimum number of methanol masers in the Galaxy to be 1275. The l-v diagram of the sample shows the tangent point of the Carina-Sagittarius spiral arm to be around 49.6 degrees, and suggests occurrence of massive star formation along the extension of the Crux-Scutum arm. A Gaussian component analysis of the maser spectra shows the mean line-width to be 0.38 km/s which is more than a factor of two larger than what has been reported in the literature. We also find no evidence that faint methanol masers have different properties than those of their bright counterparts.Comment: Accepted by ApJ; Revised footnote number 3 on page 8 based on private communicatio

    Managing multinationals: industrial policy, state institutions, and foreign direct investment in Brazil

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    Foreign Direct Investment (FDI) has increased in many countries, and it is a potential catalyst for development. Yet all FDI is not equal. This dissertation uses the case of Brazil since 1990 to demonstrate how host country political institutions can have an effect on the investment profiles of multinational firms. Specifically, I argue that innovation-intensive and efficiency-oriented FDI is relatively uncommon in Brazil due in part to the characteristics of state institutions. I develop theoretical frameworks of institutional coherence and firm incentive structures, and support my argument with original interviews and firm-level data from Brazil and other developing countries. I concentrate on the automotive and information technology industries in Brazil, which are dominated by multinational firms. I argue that increasingly integrated global value chains change the context for host country governments and industrial policy, but that states do retain influence over both the production models pursued by firms and potential developmental spillovers from investment

    Tissue eosinophilia induced by recombinant human interleukin-5 in the hamster cheek pouch membrane

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    Interleukin-5 (IL-5) is a cytokine that preferentially effects the development and function of eosinophils, and is considered important in the pathophysiology of allergic inflammation. In this study, we evaluated the ability of recombinant human IL-5 (rHu IL-5) to promote tissue eosinophilia and the importance of this eosinophilia to pathological alterations in vascular function. Repetitive subcutaneous administration for 18 days of rHu IL-5 resulted in a 7-fold increase in the number of eosinophils found in the ipsilateral hamster cheek pouch membrane. The contralateral cheek pouch membrane and peritoneum of these animals showed lesser but significant elevations in the number of eosinophils. In contrast, denatured rHu IL-5 did not elevate eosinophils in these tissues. Through the use of intravital microscopy and fluorometric analysis, rHu IL-5 treated hamster cheek pouch membranes were evaluated for alterations in microvascular permeability, using plasma clearance of FITC-dextran 150 as an index. Despite promoting a prominent tissue eosinophilia, the repetitive subcutaneous injections of rHu IL-5 did not alter the clearance of FITC-dextran 150. Topical application of rHu IL-5 to the cheek pouch, also, had no effect on the clearance of FITC-dextran 150. Immunofluorescence observations using an antibody to the granule protein, eosinophil peroxidase, indicated that the recruited cells had not degranulated. Our results support the importance of IL-5 in the recruitment of tissue eosinophils, but further stimulation is probably required to cause degranulation of these cells and the ensuing tissue damage

    Phase field modeling of electrochemistry I: Equilibrium

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    A diffuse interface (phase field) model for an electrochemical system is developed. We describe the minimal set of components needed to model an electrochemical interface and present a variational derivation of the governing equations. With a simple set of assumptions: mass and volume constraints, Poisson's equation, ideal solution thermodynamics in the bulk, and a simple description of the competing energies in the interface, the model captures the charge separation associated with the equilibrium double layer at the electrochemical interface. The decay of the electrostatic potential in the electrolyte agrees with the classical Gouy-Chapman and Debye-H\"uckel theories. We calculate the surface energy, surface charge, and differential capacitance as functions of potential and find qualitative agreement between the model and existing theories and experiments. In particular, the differential capacitance curves exhibit complex shapes with multiple extrema, as exhibited in many electrochemical systems.Comment: v3: To be published in Phys. Rev. E v2: Added link to cond-mat/0308179 in References 13 pages, 6 figures in 15 files, REVTeX 4, SIUnits.sty. Precedes cond-mat/030817
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