648 research outputs found

    Moving dunes on the Google Earth

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    Several methods exist for surveying the dunes and estimate their migration rate. Among methods suitable for the macroscopic scale, the use of the satellite images available on Google Earth is a convenient resource, in particular because of its time series. Some examples of the use of this feature of Google Earth are here proposed.Comment: Keywords: Dunes, Dune Migration, Satellite Imagery, Google Earth, Image Processin

    Faience: the ceramic technology of ancient Egypt

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    Faiences are ancient Egyptian ceramic materials, considered as "high-tech" products. The paper discussed the method by which the faiences were produced and the application of SEM and Raman spectroscopy to their analysi

    Discussion of the De Generatione Sonorum, a treatise on sound and phonetics by Robert Grosseteste

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    Here I am proposing a translation and discussion of the De Generatione Sonorum, one of the short scientific treatises written by Robert Grosseteste. The subject is the sound and the phonetics. In this treatise we find a discussion of oscillations and elasticity of materials and the description of some motions and their combinations to

    Jerk and Hyperjerk in a Rotating Frame of Reference

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    Jerk is the derivative of acceleration with respect to time and then it is the third order derivative of the position vector. Hyperjerks are the n-th order derivatives with n>3. This paper describes the relations, for jerks and hyperjerks, between the quantities measured in an inertial frame of reference and those observed in a rotating frame. These relations can be interesting for teaching purposes.Comment: Rotating frames, Physics education researc
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