304 research outputs found

    Online-Bestimmungshilfe für Schadorganismen für das Internetportal www.oekolandbau.de

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    Organic plant protection can be supported by diagnostic aids for pest organisms. A concept for a user-friendly, scientifically founded diagnostic aid for agriculturally relevant pest organisms is presented, which is based on a flexible filter structure and conclusive images. To provide practical information on biology and regulation options along with the diagnosis, recent scientific results and market availability of regulation options in organic farming are being reviewed. The on-going research and transfer project has launched the first section on storage pests in 2016 at: www.oekolandbau.de/erzeuger/pflanzenbau/allgemeiner-pflanzenbau/pflanzenschut

    Dewetting of thin films on heterogeneous substrates: Pinning vs. coarsening

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    We study a model for a thin liquid film dewetting from a periodic heterogeneous substrate (template). The amplitude and periodicity of a striped template heterogeneity necessary to obtain a stable periodic stripe pattern, i.e. pinning, are computed. This requires a stabilization of the longitudinal and transversal modes driving the typical coarsening dynamics during dewetting of a thin film on a homogeneous substrate. If the heterogeneity has a larger spatial period than the critical dewetting mode, weak heterogeneities are sufficient for pinning. A large region of coexistence between coarsening dynamics and pinning is found.Comment: 4 pages, 4 figure

    Theoretical approach to two-dimensional traffic flow models

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    In this paper we present a theoretical analysis of a recently proposed two-dimensional Cellular Automata model for traffic flow in cities with the novel ingredient of turning capability. Numerical simulations of this model show that there is a transition between a freely moving phase with high velocity to a jammed state with low velocity. We study the dynamics of such a model starting with the microscopic evolution equation, which will serve as a basis for further analysis. It is shown that a kinetic approach, based on the Boltzmann assumption, is able to provide a reasonably good description of the jamming transition. We further introduce a space-time continuous phenomenological model leading to a couple of partial differential equations whose preliminary results agree rather well with the numerical simulations.Comment: 15 pages, REVTeX 3.0, 7 uuencoded figures upon request to [email protected]
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