CuGaS2 and CuGaS2–ZnS porous layers from solution-processed nanocrystals

The manufacturing of semiconducting films using solution-based approaches is considered a low cost alternative to vacuum-based thin film deposition strategies. An additional advantage of solution processing methods is the possibility to control the layer nano/microstructure. Here, we detail the production of mesoporous CuGaS2 (CGS) and ZnS layers from spin-coating and subsequent cross-linking through chalcogen-chalcogen bonds of properly functionalized nanocrystals (NCs). We further produce NC-based porous CGS/ZnS bilayers and NC-based CGS–ZnS composite layers using the same strategy. Photoelectrochemical measurements are used to demonstrate the efficacy of porous layers, and particularly the CGS/ZnS bilayers, for improved current densities and photoresponses relative to denser films deposited from as-produced NCs.Peer ReviewedPostprint (published version

Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

Here we present a revised geomagnetic reference model for the region comprising Albanian territory, south-east part of Italian Peninsula and Ionian Sea from 1990 to 2010 with prediction to 2012. This study is based on the datasets of magnetic measurements taken during different campaigns in Albania and Italy in the time of concern, together with a total intensity data set from the Ørsted and CHAMP satellite missions. The model is designed to represent the Cartesian components, X, Y, Z and the total intensity F of the main geomagnetic field (and its secular variation) for the period of interest. To develop the model, we applied a Spherical Cap Harmonic Analysis (SCHA) of the geomagnetic potential over a 16° cap with most of the observations concentrated in the central 4° half-angle. The use of a larger cap than that containing the data was made to reduce the typical problems in SV modelling over small regions. Also a new technique, called ``Radially Simplified Spherical Cap Harmonic Analysis" (RS-SCHA), was developed to improve the model especially in the radial variation of the geomagnetic field components. Both these models provide an optimal representation of the geomagnetic field in the considered region compared with the International Geomagnetic Reference Field model (IGRF-11) and can be used as reference models to reduce magnetic surveys undertaken in the area during the time of validity of the model, or to extrapolate the field till 2012

Comparison of microstructure and mechanical properties at different length scales of WC-Co hardmetals consolidated by binder jetting 3D printing and hip

Additive Manufacturing (AM) is rapidly growing as a revolutionary technique. It provides an interesting ability to produce complex geometries, a key feature for enhancing performance and widening application fields of hardmetal components, limited characteristic for traditional processing techniques. Within this context, it is necessary to study the mechanical integrity of samples produced by AM [AMed] where it is expected to find characteristics linked to the shaping route followed, and study if they will have influence on the final behaviour regarding the mechanical properties expect for a specimen process by a traditional manufacturing route. This work aims to study the final microstructure, mechanical properties and layer assemblage at different length scales for a 12%wtCo– WC grade hardmetals of medium grain size consolidated by binder jetting 3DP and subsequent SinterHIP. In addition, compare this results with the ones obtained from a 12%wtCo–WC specimens process by means of a traditional technique like Hot Isostatic Pressing (HIP) using the same raw material like in the AMed specimens. Hardness Vickers at macro- and microlength scale as well as scratch tests, using different loads and indenter tips, are conducted on both type of samples. The results are analysed and discussed in terms of oriented layer-like material assemblage effects on microstructural variability, mechanical response determined by intrinsic physical behaviour of the material and feedstock used

Preuves d’extensions flexurales dans l’avant-pays rifain : le bassin du Rharb-Mamora (Nord Maroc)

Le bassin du Rharb représente l’avant-pays de la Cordillère du Rif. La Mamora (nord du Maroc) correspond à la bordure méridionale de ce bassin entre les nappes pré-rifaines alpines au nord et la Meseta hercynienne au sud. La Mamora, largement couverte par des formations actuelles, l’analyse du potentiel des ressources naturelles, leur exploitation et leur gestion cohérente nécessitent une bonne connaissance des diverses formations et de leurs structures. L’analyse et l’interprétation de profils sismiques, de forages hydrogéologiques et pétroliers ont permis de préciser les structures majeures de la Mamora, largement recouvertes par des sédiments néogènes. La structure de cette région est contrôlée par des failles au moins hercyniennes, bien connues dans le substratum paléozoïque. Les deux grandes familles, NE-SW et NW-SE, ont contrôlé l’évolution paléogéographique (répartition des faciès et variations de la puissance des formations). La faille majeure dans cette région est la faille Kénitra – Sidi-Slimane (FK2S) [Zouhri et al., 2001]. Cette faille N110oE, à fort pendage N, est localisée au S du front de la nappe pré-rifaine dont l’amortissement est aveugle. Elle se traduit par un effondrement progressif vers le N. Il pourrait s’agir d’une réplique de la faille Rabat – Tiflet. La Mamora apparaît ainsi comme une charnière entre le Rharb subsident et la Meseta marocaine stable depuis le Mésozoïque

ITalian Geomagnetic Reference Field (ITGRF): update for 2000 and secular variation model up to 2005 by autoregressive forecasting

The updated version of the ITalian Geomagnetic Reference Field (ITGRF) for 2000.0 and its secular variation model up to 2005.0 are presented in this paper. The main field model is based on a simple polynomial approximation in latitude and longitude of the geomagnetic field elements computed from IGRF on a 12° ¥ 11° grid centred over Italy. The annual means from L'Aquila observatory were used to determine the baseline level, imposing a constant observatory anomaly bias. This procedure gives a set of 6 coefficients every 5 years from 1960 to 2005 for the horizontal H, total field F, vertical Z and declination D elements of the geomagnetic field. The extrapolation of ITGRF to 2005 is based on an autoregressive forecasting of the L'Aquila observatory annual means. Comparison of the field values computed from the model with those recorded at the other Italian observatory (Castello Tesino) shows that the ITGRF improves the fit of the secular variation pattern with respect to the global IGRF model by a factor of 3. The ITGRF represents a reliable alternative to global models when reducing magnetic surveys to a common reference epoch over the Italian region

Deep seafloor magnetic observations under GEOSTAR project

Performing good quality magnetic observations is not an easy task; making them in the extreme marine environment is even much more challenging. The European funded GEOSTAR project succeeded in reaching this difficult goal. After the shallow seawater test experiment performed in the Adriatic sea in 1998, the main aims of the GEOSTAR project were achieved two years later during the six-month deep seafloor mission in the Tyrrhenian sea at around 2 km depth. Details and results about the shallow seawater mission in the Adriatic sea were published in previous articles; this paper is concerned with the deep seafloor mission in the Tyrrhenian sea close to Ustica Island and presents some results related to the geomagnetic recordings

Surface chemistry and nano-/microstructure engineering on photocatalytic In2S3 nanocrystals

Colloidal nanocrystals (NCs) compete with molecular catalysts in the field of homogenous catalysis, offering easier recyclability and a number of potentially advantageous functionalities, such as tunable band gaps, plasmonic properties, or a magnetic moment. Using high-throughput printing technologies, colloidal NCs can also be supported onto substrates to produce cost-effective electronic, optoelectronic, electrocatalytic, and sensing devices. For both catalytic and technological application, NC surface chemistry and supracrystal organization are key parameters determining final performance. Here, we study the influence of the surface ligands and the NC organization on the catalytic properties of In2S3, both as a colloid and as a supported layer. As a colloid, NCs stabilized by inorganic ligands show the highest photocatalytic activities, which we associate with their large and more accessible surfaces. On the other hand, when NCs are supported on a substrate, their organization becomes an essential parameter determining performance. For instance, NC-based films produced through a gelation process provided five-fold higher photocurrent densities than those obtained from dense films produced by the direct printing of NCs.Peer ReviewedPostprint (author's final draft

Des mesures de gestion pour adapter les espaces forestiers méditerranéens aux effets des changements climatiques

Il est prévu que les changements climatiques auront de nombreux impacts sur les peuplements forestiers méditerranéens. Les gestionnaires de ces espaces sont donc confrontés au besoin de prendre des décisions orientées pour améliorer leur capacité d’adaptation face à ces changements. C’est dans ce contexte que le projet ForClimadapt est né. L’article présente deux actions démonstratives conduites dans les Pré-Pyrénées catalanes visant d’une part la réduction de la vulnérabilité des peuplements forestiers face aux grands feux de forêt et, d’autre part, l’augmentation de l’adaptabilité et de la résilience des forêts par la réalisation d’un ensemble de plantations d’enrichissement en pinèdes sous-méditerranéennes monospécifiques