Characterization of materials and conservation process of the collection of arabic manuscript documents of Granada Archivo Histórico Provincial

El texto que presentamos recoge las principales conclusiones que han derivado de los estudios sobre la Colección de documentos árabes del Archivo Histórico Provincial de Granada. Compuesta principalmente por documentos de carácter jurídico, el análisis del contenido de cada uno de ellos en relación con la materialidad del soporte y las tintas así como la coincidencia en el diseño y planificación de la página revelan el uso de idénticos protocolos de ejecución. Esta investigación nos está permitiendo, además, establecer coincidencias relevantes relacionadas con los procesos de elaboración del papel entre los últimos años de permanencia de los árabes en la Península Ibérica y los primeros tras la incorporación del territorio a la Corona de Castilla y, sobre todo, con el modo de ejecutar el documento de archivo en sus formas externa e interna.This paper presents the main conclusions of our study of the Arabic documents preserved in the Archivo Histórico Provincial of Granada. The analysis of the contents of each document, the materials and inks used in their support, and also the similarities of the page layout reveals the use of identical production protocols. Furthermore, this research also enables us to establish important similarities between the paper production processes in the latter stages of the Islamic rule in the Iberian Peninsula and the earlier stages of its incorporation in the Crown of Castilla – in particular in relation to how the archival documents were issued, both externally and internally

Investigation of a Pt containing washcoat on SiC foam for hydrogen combustion applications

A commercial Pt based washcoat, used for catalytic methane combustion, was studied supported on a commercial SiC foam as catalytic material (Pt/SiC) for catalytic hydrogen combustion (CHC). Structural and chemical characterization was performed using Electron Microscopy, X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS). The reaction was monitored following water concentration by Fourier Transform Infrared spectra (FTIR). The FTIR method was compared with H2 detection by Gas Cromatography (GC) and has shown to be adequate to study the kinetics of the CHC reaction in steady state under our experimental conditions (very lean 1% (v/v) H2/air mixtures). The catalyst is composed of 5–20 nm disperse Pt nanoparticles decorating a mixture of high surface area Al2O3 and small amounts of ceria supported on the SiC foam which also contains alumina as binder. The Pt/SiC catalytic material has demonstrated to be active enough to start up the reaction in a few seconds at room temperature. The material has been able to convert at least 18.5 Lhydrogen min−1 gPt−1 at room temperature in conditions of excess of catalyst. The Pt/SiC material was studied after use using XPS and no significant changes on Pt oxidation states were found. The material was characterized from a kinetic point of view. From the conversion-temperature plot a T50 (temperature for 50% conversion) of 34 °C was obtained. Activation energy measured in our conditions was 35 ± 1 kJ mol−1.Peer reviewe

Microstructural evolution and properties of He-charged a-Si coatings prepared by magnetron sputtering

International audienc

SiOxNy thin films with variable refraction index: Microstructural, chemical and mechanical properties

In this work amorphous silicon oxynitride films with similar composition (ca. Si0.40N0.45O0.10) were deposited by reactive magnetron sputtering from a pure Si target under different N2-Ar mixtures. Rutherford backscattering (RBS) studies revealed that the coatings presented similar composition but different density. The mechanical properties evaluated by nanoindentation show also a dependence on the deposition conditions that does not correlate with a change in composition. An increase in nitrogen content in the gas phase results in a decrease of hardness and Young's modulus. The microstructural study by high resolution scanning electron microscopy (SEM-FEG) on non-metalized samples allowed the detection of a close porosity in the form of nano-voids (3-15 nm in size), particularly in the coatings prepared under pure N2 gas. It has been shown how the presence of the close porosity allows tuning the refraction index of the films in a wide range of values without modifying significantly the chemical, thermal and mechanical stability of the film. © 2010 Elsevier B.V. All rights reserved.Authors thank the financial support from the European Commission (Sixth Framework Programme), Project NoE EXCELL, Spanish Ministry MICINN (CONSOLIDER FUN COAT) and Junta de Andalucía (group TEP217). V. Godinho thanks the I3P program of CSIC for a pre-doctoral grant.Peer Reviewe

Low gas consumption fabrication of 3He solid targets for nuclear reactions

Nanoporous solids that stabilize trapped gas nanobubbles open newpossibilities to fabricate solid targets for nuclear reactions. A methodology is described based on the magnetron sputtering (MS) technique operated under quasistatic flux conditions to produce such nanocomposites films with 3He contents of up to 16 at.% in an amorphous-silicon matrix. In addition to the characteristic low pressure (3–6 Pa) needed for the gas discharge, the method ensures almost complete reduction of the process gas flow during film fabrication. The method could produce similarmaterials to those obtained under classical dynamic flux conditions forMS. The drastic reduction (N99.5%) of the gas consumption is fundamental for the fabrication of targets with scarce and expensive gases. Si:3He and W:3He targets are presented together with their microstructural (scanning and transmission electron microscopy, SEM and TEM respectively) and compositional (Ion Beam Analysis, IBA) characterization. The 3He content achieved was over 1 × 1018 at/cm2 for film thicknesses between 1.5 and 3 μm for both Si and Wmatrices. First experiments to probe the stability of the targets for nuclear reaction studies in inverse kinematics configurations are presentedPeer reviewe

Dusty starbursts masquerading as ultra-high redshift galaxies in JWST CEERS observations

Lyman Break Galaxy (LBG) candidates at z ≳ 10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well-detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z ≲ 7) may also mimic the near-infrared colors of z > 10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z ≈ 5.1. We also present a tentative 2.6σ SCUBA-2 detection at 850 µm around a recently identified z ≈ 16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z ∼ 5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z ∼ 4 − 6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and 2 The CEERS collaboration strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra high-redshift LBG candidates from JWST observations