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The study of adornments found in the necropolis at Valle de las Higueras (Huecas, Toledo) has determined the morphotypology and mineral composition of one quadrangular pendant and 341 stone beads. Most of the beads are short (length ≤ 5 mm), but within this regularity series can be differentiated that might be the result of standardised fabrication processes and different times of acquisition. Portable X-ray fluorescence (p-XRF) and X-ray diffraction (XRD) analysis identified the use of phyllosilicates as sepiolite and clinochlore, and above all variscite, a mineral that became especially important for adornments in the Iberian Peninsula in the 3rd millennium BC. The inland location of the necropolis, distant from source areas, certifies its remote origin, as far away as northwest Zamora according to the chronological framework. It is still not possible to determine for sure the source of the variscite at Valle de las Higueras. However, the inland location of the necropolis, distant from source areas, certifies its remote origin. The chronology suggests that it might have come from the north-west, in the area of Zamora. Archaeological and chronological data obtained in tombs in the necropolis, together with other inland sites, contribute to understanding variscite circulation in the Iberian Peninsula in the Chalcolithic. It was restricted to a few individuals, both adults and children, who wore necklaces and bracelets. Distance did not condition the arrival of variscite, but the small amounts suggest it was traded together with other ostentation elements, such as sea shells, cinnabar and amber. The heterogeneous regional panorama displays differences in the demand, use and acquisition of variscite depending on the socioeconomic organisation and connection to exchange networks.

Carlos Ribeiro (1813-1882) geólogo e arqueólogo. Homenagem da Câmara Municipal de Oeiras e da Academia das Ciências de Lisboa nos 200 anos do seu nascimento Submitted by joão Cardoso (arqueolo@univ-ab.pt) on 2014-12-11T10:20:23Z No. of bitstreams: 1 EAO 20 _variscites.pdf: 3819936 bytes, checksum: e2e46e11376fdaeed923786d9e84522f (MD5) Approved for entry into archive by joão Cardoso (arqueolo@univ-ab.pt) on 2014-12-11T10:20:33Z (GMT) No. of bitstreams: 1 EAO 20 _variscites.pdf: 3819936 bytes, checksum: e2e46e11376fdaeed923786d9e84522f (MD5) Made available in DSpace on 2014-12-17T16:05:45Z (GMT). No. of bitstreams: 1 EAO 20 _variscites.pdf: 3819936 bytes, checksum: e2e46e11376fdaeed923786d9e84522f (MD5) Previous issue date: 2013

Se exponen los resultados de algunas muestras alteradas procedentes de la Puerta del Perdón, pertenecientes a la Mezquita de Córdoba. Algunas de las muestras de metal analizadas mediante difracción de rayos X y microanálisis por energía dispersiva de rayos X estaban constituidas por latón (cobre con pequeñas cantidades de zinc), mientras que otras estaban constituidas por bronce (cobre, estaño y plomo). La superficie de las muestras se analizó empleando las mismas técnicas. Asimismo, se usó espectroscopia de infrarrojos. El componente principal identificado en la superficie de la puerta es cloruro básico de cobre (atacamita). Además se han encontrado cloruros de plomo. Estos datos demuestran que la repentina alteración de la superficie se puede atribuir al uso de productos de limpieza con alto contenido en cloro. Otros compuestos procedentes de la contaminación externa, como yeso, cuarzo y oxalatos también se detectaron en la superficie.

This article presents an online tool to model the characteristic I-V curve of a photovoltaic (PV) panel in real time. This tool is implemented on a friendly web (https://www.pvmodel.umh.es) and its use is completely free. The main functionality is the calculation of the five parameters of the PV single-diode model, either with real measurements of the PV module or with the data provided in the datasheet of a PV module. In the first case, the two methods that currently obtain the best results so far in two well-known cases study in the literature, the so-called Two-step linear least-square (TSLLS) method and the Reduced Form (RF) method, can be executed, in the second case, it is used a new method that allows obtaining the infinite sets of five parameters that satisfy the three remarkable points of the datasheet, that is, the short-circuit, the open-circuit and the maximum power points. Besides the PV model calculated can be also downloaded as an LTspice subcircuit so it can be used directly in electric or electronic simulations. In addition, some I-V curves data examples and PV modules datasheets data are provided so the user can test the tool directly.

The objective of this paper is to determine all the possible combinations of the five parameters of the single-diode model (SDM) of a photovoltaic panel when only the following three important points (remarkable points) of a I–V curve, namely, short circuit, maximum power and open circuit points, are available, usually from manufacturer’s datasheet. In this work, four of the five parameters of the SDM are expressed as explicit functions of the remaining one. Taking advantage of this, the monotony of these functions has been studied and the intervals where the corresponding parameters belong have been determined, that is, the domain of the parameters, in terms exclusively of the remarkable points. Using these functions, a unique SDM solution can be also easily determined if an extra data or equation is available. A possible application of this study is to validate if an extra equation is compatible with the set of equations obtained from the remarkable points. The results presented in this paper have been tested with a database gathering information of 8835 datasheets included in the Energy Commission’s Solar Equipment Lists. Comparisons have also been made with other works which have tried to obtain the SDM parameters only with datasheet information.