55 research outputs found

    Moving boulders in flash floods and estimating flow conditions using boulders in ancient deposits

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    Boulders moving in flash floods cause considerable damage and casualties. More and bigger boulders move in flash floods than predicted from published theory. The interpretation of flow conditions from the size of large particles within flash flood deposits has, until now, generally assumed that the velocity (or discharge) is unchanging in time (i.e. flow is steady), or changes instantaneously between periods of constant conditions. Standard practice is to apply theories developed for steady flow conditions to flash floods, which are however inherently very unsteady flows. This is likely to lead to overestimates of peak flow velocity (or discharge). Flash floods are characterised by extremely rapid variations in flow that generate significant transient forces in addition to the mean-flow drag. These transient forces, generated by rapid velocity changes, are generally ignored in published theories, but they are briefly so large that they could initiate the motion of boulders. This paper develops a theory for the initiation of boulder movement due to the additional impulsive force generated by unsteady flow, and discusses the implications. Keywords

    Ferulic acid and derivatives: molecules with potential application in the pharmaceutical field

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    ATLAS detector and physics performance: Technical Design Report, 1

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    Beschichtungen zur Verminderung von Umweltbelastungen bei Umformprozessen. Teilthema: Untersuchungen zum Einsatz beschichteter Umformwerkzeuge Abschlussbericht

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    SIGLEAvailable from TIB Hannover: F97B1114+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

    Observation of a chiral state in a microwave cavity

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    A microwave cavity experiment to measure the phase difference θ0 between two points of a filed distribution inside the resonator was performed. As such, the technique was applied to the superposition of two eigenmodes on a path to an EP. According to this, it represents the first experimental observation of a mode in a microwave resonator, where the electric field oscillates with a phase difference of 90° at two different points.Articl

    Laermschutzvorrichtung fuer den Werkzeugraum von Karosseriepressen bei vorrangiger Handbeschickung

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    Available from TIB Hannover: RO 146(71) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEArbeitsgemeinschaft Industrieller Forschungsvereinigungen e.V., Koeln (Germany); Bundesministerium fuer Wirtschaft, Bonn (Germany)DEGerman
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