2,263 research outputs found

    Solution of the problem of composite charge using R.D.38

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    In this paper the author has solved the problem of internal ballistics of composite charge using 'R.D.38' method which is based upon the usual isothermal approximation. A linear law of burning has been assumed

    Author index

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    The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.This is a continuation of the "Author and Subject Index to the Onderstepoort Journal of Veterinary Science and Animal Industry (1933- l950)" and the "Onderstepoort Journal of Veterinary Research (1951 - 1968)" which appeared in June 1969 and covers the period 1969 to 1973, i.e. Volumes 36 to 40. As from 1974 (Volume 41) it is intended to furnish an Author and Subject Index in Number 4 of each volume covering all four numbers for that particular year

    Noise due to unsteady flow past trailing edges

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    This paper presents two-dimensional direct numerical simulations (DNS) of noise generated at trailing edges (TE) with zero thickness. The simulations are conducted specifying either no-slip or slip walls in order to investigate viscous effects. In both cases, small amplitude disturbances are introduced close to the inflow boundary that serve as pressure disturbances at the TE. DNS data reveals that the unsteady Kutta condition is not satisfied, irrespective of the wall boundary condition. However, it appears that the validity of the unsteady Kutta condition is not essential for making an accurate prediction of the far field noise. The far field pressure is predicted as a function of the surface pressure difference using a 2-D modification of Amiet's classical theory, and compared with the far field pressure computed directly. Directivity plots provide evidence that the presence of boundary layers and noise generated by an unsteady wake in the no-slip cases lead to smearing of individual lobes, and that the downstream pointing lobes in no-slip wall cases are probably due to nonlinear noise generation in the wake. The simulations are conducted using a high-order accurate numerical method which is free of upwinding, artificial dissipation or any form of explicit filtering, and employs a novel boundary treatment

    Response of British lichens to climate change scenarios: trends and uncertainties in the projected impact for contrasting biogeographic groups

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    Projection of species-response to climate change scenarios is a key tool in conservation strategy. Previous studies have projected climate change impacts for animal and vascular plant species using the ‘bioclimatic envelope’ approach. In this study we apply the principles of the bioclimatic envelope approach to examine the response of 26 lichen species whose distributions are well characterised within the British Isles. Lichen species were subjectively selected based on their contrasting distributions, and their ecological traits, which fulfilled as closely as possible the assumptions of the bioclimatic envelope method. We used a split-sampling approach to model the species-response to present-day climate using confirmed records and pseudo-absences as input data, and testing each model against an ‘independent’ calibration dataset. Predictive models were projected using standard climate change scenarios comprising the UKCIP02 data. Projections indicate broad trends in the response of species placed into contrasting biogeographic groups, and point to the potential for significant change in the spatial distribution of the British lichen flora. We highlight putative threats to montane and Boreal elements of the lichen flora, and emphasise significant uncertainty in projected response of the UK’s internationally important oceanic flora

    Characteristic distribution and scale interaction of turbulence in a boundary layer

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    This work revisits the concept of turbulent boundary layers from a novel perspective on scale transfer. Turbulence production and dissipation together with the energy budgets are analyzed in the velocity gradient invariant phase space. In combination with filtering, the mechanism of scale coupling is investigated and illustrated for different characteristic flow topologies. The understanding of the scale coupling is important to model turbulence. Turbulence models describe the complex interaction of the scales of motion in a simplified form. The essential task of turbulence modeling is to capture the coupling of the modeled and unmodeled scales as well as the evolution of the modeled scales within the unmodeled flow. This work characterizes the scale coupling by focusing on the interfaces between modeled and unmodeled flow such as production and dissipation. The mechanisms that govern the evolution of the modeled quantities are investigated for their core properties and universal features. Direct numerical simulation (DNS) is carried out to obtain data of a compressible zero pressure-gradient flat plate turbulent boundary layer flow. This flow topology allows to unveil the effect of a wall on the coupling of scales and evolution of turbulence

    Learning from One's Mistakes

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    Created by R.D. Lee for the Royal Statistics Society, this article describes an exercise, which highlights the effect of sampling without replacement in small populations, and leads to consideration of the relative importance of sample and population size when examining standard error. The author provides a number of exercises, an explanation of statistical errors and the importance of sample size. This is a brief, yet fine resource for those in the field of statistics

    Mad to be Normal: Thoughts on Psychiatrist R.D Laing and Connections to Liberation Psychology

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    This article uses the film Mad to be Normal, about R.D. Laing, as an opening into the liberation psychology approaches of Martin-Baro. Examples from the author\u27s own clinical practice as well as personal experiences from life in a Catholic Worker community are  included

    R.D. Laing's language of experience

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    The radical psychiatrist R.D. Laing (1927-1989) was an accomplished author with an extensive philosophical knowledge that informed his ideas on reading, writing, and interpretation. Laing argues that psychiatry should be modeled on skilful textual exegesis rather than scientific explanation. The exegesis of a psychotic’s words and actions is difficult, he infers, because the impoverishment of our experience cuts us off from the sense that lies within seeming madness. Like philosophers such as Edmund Husserl, Laing therefore criticizes the way in which the natural sciences have invalidated subjective experience. He consequently employs a rhetoric designed to disclose with renewed vigor its complexity, variety and reality. Laing fails, however, to find an alternative to scientific reason: "experience", in his weakest work, is an irrational realm of mystical and self-validating certainty that closely parallels Heidegger’s later accounts of "Being"

    Accurate assessment of kidney function in Indigenous Australians: the estimated GFR study

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    Link to a related website: http://espace.cdu.edu.au/view/cdu:38432/Maple_Brown_38432.pdf, Open Access via UnpaywallAbstract not availableLouise J. Maple-Brown, Jaquelyne T. Hughes, Paul D. Lawton, Graham R.D. Jones, Andrew G. Ellis, Katrina Drabsch, Alex D.H. Brown, Alan Cass, Wendy E. Hoy, Richard J. MacIsaac, Kerin O'Dea and George Jerum
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