563 research outputs found

    Shine on you crazy diamond: Symbolism and social use of fluorite ornaments in Iberia’s late prehistory

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    Fluorite ornaments have been recorded in different sites of Europe since Upper Paleolithic. Due to its visual appearance and physical properties, some translucent or transparent mineralogies like fluorite were searched for or casually acquired by late prehistory’s human communities. After intensive research on archaeological contexts from the Iberian Peninsula with personal ornaments from 4th to 2nd millennia BCE, we have recently identified and characterized for the first time an important number of fluorite ornaments, confronting a previous background where little attention was paid. Our work has been carried out in different archaeological collections and museums from the whole Iberian Peninsula by non-destructive techniques (Raman spectroscopy, portable X-ray fluorescence (p-XRF) and X-ray Diffraction (XRD), that revealed the nature of fluorite ornaments and points to its consideration as scarce and highly symbolic items during late prehistory. A total of 36 fluorite beads from 23 sites are here recorded and studied, many of them unpublished or wrong catalogued as other mineralogies. These adornments could have important roles in trade and use among the communities of Iberia from the 4th millennium BCE onwards, because of their scarcity and its recurrent association with important funerary complex and exotic materials. Fluorite ornaments could have been significant and special symbols in the development of new and exclusive raw materials in the context of increasing social complexity and inequality

    Distribución y consumo de cuentas de fluorita y translúcidas en la península ibérica del VI al II milenios ANE

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    Translucent minerals were valued in prehistoric societies for their rarity and socially used as highly symbolic elements. This work addresses the use and nature of Iberian translucent beads. We present the results of chemical (Raman spectroscopy, portable X-ray fluorescence, X-ray diffraction and visible (Vis)/near-infrared (NIR) spectroscopy) and contextual analyses and provide a review of the archaeological literature on the manufacture and use of translucent items during Iberian Late Prehistory. A total of 54 translucent beads from 47 sites, primarily burials, were analyzed; 33 were made from fluorite, while the remaining 21 were made of diverse translucent minerals (calcite, quartz and different silicates). The scarcity of translucent items in the archaeological record, the regional and supraregional scale of its exchange, and its recursive association to other valuables in singular contexts reinforces the idea that their owners/wearers enjoyed a high status.info:eu-repo/semantics/publishedVersio

    An Arduino-Based Talking Calorimeter for Inclusive Lab Activities

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    UID/QUI/50006/2019 POCI-01-0145-FEDER-007265 PEest/UID/CEC/04516/2019 02/2018/ARNI (International Academic Mobility Program.PMAI) 10/2018/PROPPIT (Course Completion Work Program.PROTCC)This work describes a simple talking calorimeter for the visually impaired based on the Arduino Uno without any shield. An electronic interface was designed using a Wheatstone bridge, a thermistor, or an operational amplifier (opamp). The temperature values are communicated by a loudspeaker connected to pulse-width modulation (PWM) digital output pins 3 and 11 of the Arduino Uno. The system is based on the Talkie library for Arduino Uno. This library was developed using Linear Predictive Coding and includes about 1000 English words. Two new Talkie libraries were constructed, one for Portuguese and another for German. This device can be easily implemented in any teaching laboratory with extremely reduced costs.publishersversionpublishe

    THE STUDY OF SWIMMERS’S HAND AND FOREARM USING COMPUTATIONAL FLUID DYNAMICS

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    Computational Fluid Dynamics has been widely used in biomechanics studies applied to medicine and sport. In this study we developed a 3-D model for swimmer’s hand/forearm forces using Computational Fluid Dynamics. Models used in the simulations were created in CAD, based on realistic dimensions of a right adult human hand/forearm. The governing system of equations considered was the incompressible Reynolds averaged Navier-Stokes equations implemented with Fluent® code. The drag coefficient was the main responsible for propulsion, with a maximum value of force propulsion corresponding to a pitch angle of 90º. The lift coefficient seemed to play a less important role in the generation of propulsive force with pitch angles of 0º and 90º but it is important with a pitch angle of 45º. It was demonstrated the relevance of applying CFD in the propulsive force measurements, using a more realistic model of a human segment

    Stellar Astrophysics and Exoplanet Science with the Maunakea Spectroscopic Explorer (MSE)

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    The Maunakea Spectroscopic Explorer (MSE) is a planned 11.25-m aperture facility with a 1.5 square degree field of view that will be fully dedicated to multi-object spectroscopy. A rebirth of the 3.6m Canada-France-Hawaii Telescope on Maunakea, MSE will use 4332 fibers operating at three different resolving powers (R ~ 2500, 6000, 40000) across a wavelength range of 0.36-1.8mum, with dynamical fiber positioning that allows fibers to match the exposure times of individual objects. MSE will enable spectroscopic surveys with unprecedented scale and sensitivity by collecting millions of spectra per year down to limiting magnitudes of g ~ 20-24 mag, with a nominal velocity precision of ~100 m/s in high-resolution mode. This white paper describes science cases for stellar astrophysics and exoplanet science using MSE, including the discovery and atmospheric characterization of exoplanets and substellar objects, stellar physics with star clusters, asteroseismology of solar-like oscillators and opacity-driven pulsators, studies of stellar rotation, activity, and multiplicity, as well as the chemical characterization of AGB and extremely metal-poor stars.Comment: 31 pages, 11 figures; To appear as a chapter for the Detailed Science Case of the Maunakea Spectroscopic Explore
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