52,535 research outputs found
Three New Species of Hyperaspis from Eastern North America (Coleoptera: Coccinellidae)
Excerpt: A number of apparently related species, including the three which are newly described in this paper, belong to the large binotata group of Dobzhansky (1941). It has been found necessary to re-examine this group and to divide it into smaller, more homogeneous species clusters. These new species clusters may indicate more clearly the relationships of the species involved
ILDG Middleware Working Group Status Report
We report on the status of the ILDG Middleware Working Group.Comment: Lat2004(ILDG
Carool Kersten, Islam in Indonesia; the Contest for Society, Ideas and Values. London: Hurst & Company, 2015, XX + 373 Pp. ISBN: 9781849044370. Price: GBP 25.00 (Soft Cover).
Market anticipations of monetary policy actions - commentary
Monetary policy ; Federal funds rate
Assessing changes in the monetary transmission mechanism: a VAR approach : commentary
Paper for a conference sponsored by the Federal Reserve Bank of New York entitled Financial Innovation and Monetary TransmissionEconomic conditions - United States ; Monetary policy
Noise suppression characteristics of peripherally segmented duct liners
The acoustic fields and transmission losses produced in semi-infinite circular ducts with peripherally segmented liners are analyzed using a series expansion of hard-wall duct modes. The coefficients of the series are computed using Galerkin's method. Unlike finite element approaches, this analysis includes the effects of realistic sources and the number of peripheral strips need not be small. It is shown that peripherally segmented liners redistribute the acoustic energy in waves composed of only a single circumferential mode at the source into other waves which contain a multitude of circumferential modes in the lined section. The accuracy of eigenfunctions computed from the analysis was observed to increase as either the frequency or radial mode order increased. The transmission losses were found to be accurate at frequencies above the cut-on value of the first-order radial mode in a hard-wall duct. The results show that for plane wave sources, peripherally segmented liners may attenuate as much sound as an optimized uniform liner at the optimal point while giving more noise suppression at most other frequencies
Explaining the increased variability in long-term interest rates
Interest rates ; Federal funds rate
A method for determining acoustic-liner admittance in ducts with sheared flow in two-cross-sectional directions
A method is developed for determining the acoustic admittance of a test liner installed in the wall of a grazing flow impedance tube. The mean flow is permitted flow gradients in both cross-sectional directions of the tube. The unknown admittance value is obtained by solving an eigenvalue problem. This eigenvalue problem results from the application of the finite-element method to the partial differential equation and boundary conditions governing the acoustic field. The credibility of the method is established by comparing results with exact solutions obtained for a constant mean-flow profile and with previous results for cases involving shear in only one cross-sectional direction. Excellent comparisons are obtained in both cases. The analysis is used in conjunction with a limited amount of experimental data and shows that the flow must be accurately modeled in order to determine the acoustic-liner properties
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