23,961 research outputs found

    Brown-Tail Moth, \u3ci\u3eEuproctis Chrysorrhoea,\u3c/i\u3e an Indigenous Pest of Parks and Public in the Benelux Countries (Lepidoptera: Lymantriidae)

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    Euproctis chrysorrhoea is a pest of park and shade trees and of the public in the Benelux countries as well as in the northeastern United States and Canada. In the Benelux countries the brown-tail moth is present every year in the dune regions, where it mainly feeds on Hippophae rhamnoides. Hairs from the larvae are irritating to the human skin producing a papular urticaria. An outbreak of the caterpillars produced widespread discomfort at a beach in the Netherlands in 1982 following defoliation of food plants and migration of the larvae seeking food, with resulting human contact, as well as wind dispersal of the hairs

    The aerospace technology laboratory (a perspective, then and now)

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    The physical changes that have taken place in aerospace facilities since the Wright brothers' accomplishment 78 years ago are highlighted. For illustrative purposes some of the technical facilities and operations of the NASA Lewis Research Center are described. These simulation facilities were designed to support research and technology studies in aerospace propulsion

    Analysis of plasma-nitrided steels

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    The analysis of plasma nitrided steels can be divided to two main categories - structural and chemical. Structural analysis can provide information not only on the hardening mechanisms but also on the fundamental processes involved. Chemical analysis can be used to study the kinetics for the nitriding process and its mechanisms. In this paper preliminary results obtained by several techniques of both categories are presented and the applicability of those techniques to the analysis of plasma-nitrided steels is discussed

    The compatible conversion system

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    Compatible conversion system centralizes the solution of general problems arising from the use of direct access mass storage. It also provides a simple stable interface for the conversion of production programs to process on third generation computer system

    Application of advanced on-board processing concepts to future satellite communications systems

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    An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development

    FEniCS-HPC: Automated predictive high-performance finite element computing with applications in aerodynamics

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    Developing multiphysics finite element methods (FEM) and scalable HPC implementations can be very challenging in terms of software complexity and performance, even more so with the addition of goal-oriented adaptive mesh refinement. To manage the complexity we in this work present general adaptive stabilized methods with automated implementation in the FEniCS-HPC automated open source software framework. This allows taking the weak form of a partial differential equation (PDE) as input in near-mathematical notation and automatically generating the low-level implementation source code and auxiliary equations and quantities necessary for the adaptivity. We demonstrate new optimal strong scaling results for the whole adaptive framework applied to turbulent flow on massively parallel architectures down to 25000 vertices per core with ca. 5000 cores with the MPI-based PETSc backend and for assembly down to 500 vertices per core with ca. 20000 cores with the PGAS-based JANPACK backend. As a demonstration of the power of the combination of the scalability together with the adaptive methodology allowing prediction of gross quantities in turbulent flow we present an application in aerodynamics of a full DLR-F11 aircraft in connection with the HiLift-PW2 benchmarking workshop with good match to experiments

    Aspects of the Rocknest Formation, Asiak Thrust-fold Belt, Wopmay Orogen, District of Mackenzie

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    Field study of the Rocknest Formation during 1981 and 1982, and laboratory study during the fall of 1982 has produced several interesting findings which are summarized in this report. Topics are: 1) subdivision of Rocknest Formation into ten informal members, 2) Rocknest shelf cyclicity and paleogeography, 3) shelf-to- slope transitions, 4) paleoclimate, and 5) evidence of possible microbial remnants in stromatolite bioherms of the Odjick/Rocknest transition beds. Future fieldwork is outlined

    Photographic Effects Produced by Cadmium and Other Elements Under Neutron Bombardment

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    It has been found that when a duplitized x-ray film has Cd placed next to it and is then surrounded by paraffin and exposed to a neutron source, the film shows blackening under the cadmium. Under these conditions the film also shows some general blackening which is rather weak. The neutrons used in these experiments were obtained by bombarding either Li or Be with about 10 microamperes of 1.2 Mev deuterons furnished by a cyclotron. There are, of course, also p-rays incident on the Cd and the photographic film, and it was necessary to establish the blackening under the cadmium as due to slow neutrons and not to these radiations

    Quantitative Paleobathymetry of Early Proterozoic (1.9 B.Y.) Continental Slope, Rocknest Formation, Wopmay Orogen, N.W.T., Canada

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    The Rocknest Formation is an early Proterozoic (1.9 b.y.) westward-facing, rimmed carbonate shelf that evolved from a ramp developed on quartzites of the underlying Odjick Formation. Shelf interior facies are cyclic peritidal dolomites; shelf edge facies are reefal stromatolitic boundstones and intraclast/ooid grainstones, and slope facies are turbidites, slope breccias, and shelf edge breccias. The carbonates are overlain by black shales and graywackes of the Recluse Group
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