Mining for a week or for centuries: Variable aims of flint extraction sites in the Mons Basin (Province of Hainaut, Belgium) within the lithic economy of the Neolithic

The Mons Basin (Province of Hainaut, western Belgium) is a geologically rich region, particularly from the point of view of Upper Cretaceous sedimentary deposits, conducive to an important flint gathering activity during the whole regional Prehistory. Focusing on the Neolithic period, indications of flint procurement as early as the end of the 6th millennium have been recorded, but there are concrete evidences of mining sites in the region since the second half of the 5th millennium. Flint extraction activities have lasted at least until the second half of the 3rd millennium. According to literature and recent researches, eleven sites could be extraction sites, including the World Heritage site of Spiennes. This paper critically assesses the accuracy of the data available and focuses on the issue of the unequal function of these extraction sites and their socio-economic function for Neolithic communities. Is it really possible to establish a hierarchy between the extraction sites? Can different acquisition-production strategies be highlighted? These questions are dealt with by synthesizing the data concerning the methods of flint exploitation in the Mons Basin, the qualitative and quantitative characteristics of the products relative to the production intentions but also by addressing the issue of their importance in exchange networks

De la mine à l’habitat:Économie des productions minières du Bassin de Mons au Néolithique. De la fin du 5e millénaire à la fin du 3e millénaire.

info:eu-repo/semantics/nonPublishe

Multi-resonant absorption in ultra-thin silicon solar cells with metallic nanowires

International audienceWe propose a design to confine light absorption in flat and ultra-thin amorphous silicon solar cells with a one-dimensional silver grating embedded in the front window of the cell.We show numerically that multi-resonant light trapping is achieved in both TE and TM polarizations. Each resonance is analyzed in detail and modeled by Fabry-Perot resonances or guided modes via grating coupling. This approach is generalized to a complete amorphous silicon solar cell, with the additional degrees of freedom provided by the buffer layers. These results could guide the design of resonant structures for optimized ultra-thin solar cells

Hot Carrier Solar Cell: From Simulation to Devices

International audienceSingle junction III-V heterostructures based devices could overtake the Shockley-Queisser limit if thermalisation of photogenerated carriers can be strongly limited as in the hot carrier solar cell concept. Previous modelling and experiments have shown the interest of Multiple Quantum Wells heterostructures in the antimonide system and the importance of very thin structures. In this paper we report new data on the thermalisation rates in antimonide and phosphide heterostructures measured at ambient temperature. For the first time electrical control of hot carrier population is performed on hot carrier heterostructures device

Identification des paramètres d'une loi de comportement élastoplastique par indentation continue sphérique

Nous proposons une étude numérique et expérimentale de l'indentation instrumentée sphérique. L'étude numérique nous a permis de suivre l'évolution d'un certain nombre de grandeurs pouvant être déduites d'une courbe d'indentation. Pour chacune de ces grandeurs, un modèle a été déterminé pour deux lois de comportement, l'étude de ces modèles a conduit à la proposition d'une démarche de caractérisation des matériaux. L'étude expérimentale nous a permis de déterminer l'enfoncement de l'indenteur dans le matériau à partir du déplacement mesuré de l'indenteur sans aucune calibration empirique. Nous présentons de plus les résultats expérimentaux issus de l'identification des paramètres de deux lois de comportement

Design of Electric Machine Taking Into Account the Partial Discharges Phenomena for Future Hybrid Propelled Aircrafts

Designing the electric motors to propel an aircraft represents a huge challenge. The constraint of weight requires such machines to be compact. Besides, the high specific power necessary (a few kW/kg, machine cooling included) leads to an increase of the voltage range of stator winding. Such characteristics increase considerably the risk of partial discharges (PD) in the stator winding. In this paper, the design of electric motors aimed to propel a future hybrid aircraft will be presented. It will be realized using 2 tools

Studying Neolithic lithics – from a cross-border dialogue to a common language

This paper aims at introducing a recent European collaborative project dedicated to lithic studies of the Neolithic. It unites a group of archaeologists from France, the United Kingdom, Belgium, the Netherlands and Germany, who belong to different research traditions. Our first meetings stressed the need for a cross-border dialogue and a common language for lithic analysis, including raw material analysis, blank production and tool production. We began by highlighting the differences and proximities between the different approaches, the potentialities to bridge these differences, the archaeological goals and the training needed. Our project, therefore, aims to harmonise our study practices in order to promote international communication and collaboration.In diesem Beitrag soll ein kürzlich ins Leben gerufenes europäisches Gemeinschaftsprojekt vorgestellt werden, das sich mit lithischen Studien des Neolithikums befasst. Es vereint eine Gruppe von Archäolog*innen aus Frankreich, dem Vereinigten Königreich, Belgien, den Niederlanden und Deutschland, die unterschiedlichen Forschungstraditionen angehören. Unsere ersten Treffen verdeutlichten die Notwendigkeit eines grenzüber- schreitenden Dialogs und einer gemeinsamen Sprache für die lithische Analyse, zu der die Analyse des Rohmaterials, der Grundformproduktion und der Werkzeugproduktion gehören. Wir begannen damit, die Unterschiede und Gemeinsamkeiten zwischen den verschiedenen Ansätzen, die Möglichkeiten zur Überbrückung dieser Unterschiede, die archäologischen Ziele und die erforderliche Ausbildung herauszustellen. Unser Projekt zielt darauf ab, unsere Untersuchungspraktiken zu vereinheitlichen, um die internationale Kommunikation und Zusammenarbeit zu fördern

Clinical and MRI outcomes 10 years after repair of massive posterosuperior rotator cuff tears

BACKGROUND: Massive rotator cuff tears are challenging to treat, with few or no studies on long-term outcomes of repair. The purpose of this study was to report 10-year outcomes following repair of massive posterosuperior rotator cuff tears, with and without extension into the subscapularis, and to determine prognostic factors that could influence clinical scores and retear rates. METHODS: The records of 234 patients who underwent repair of a massive posterosuperior rotator cuff tear at a total of 15 centers were retrieved. Patients were asked to return for evaluation at 10 years; 78 patients could not be contacted, 7 had died, and 19 had undergone a reoperation. A total of 130 patients (68% men) with a mean age (and standard deviation) of 56.1 ± 7.7 years (range, 26 to 79 years) were evaluated clinically, and 102 of them were also evaluated using magnetic resonance imaging (MRI). The tear was confined to the supraspinatus and infraspinatus tendons in 94 shoulders and also involved the superior portion of the subscapularis in 36 shoulders. Univariable and multivariable regressions were performed to determine whether 10-year total Constant-Murley scores and repair integrity were associated with patient characteristics, tear patterns, or repair techniques. RESULTS: In the study cohort, complications were noted in 14 shoulders (11%) (stiffness in 10 and infection in 4). For the 130 shoulders evaluated clinically, the mean total Constant-Murley score improved from 53.1 ± 15.9 (range, 14 to 83) preoperatively to 78.5 ± 11.3 (range, 36 to 98) at 10 years. Of the 102 shoulders evaluated using MRI, 32 had a retear (Sugaya type IV or V). Of the 19 shoulders that underwent a reoperation (excluded from the study cohort), 9 had a retear. The overall prevalence of retears was 34%. Multivariable regression analysis revealed a significant association between the 10-year Constant-Murley score and preoperative retraction of the infraspinatus tendon, but no association between retears and any of the variables. Involvement of the subscapularis had no significant effect on preoperative or postoperative Constant-Murley scores or retear rates. CONCLUSIONS: Patients who had repair of a massive posterosuperior rotator cuff tear maintained considerable improvements in clinical and radiographic outcomes at 10 years. Partial concomitant tears of the subscapularis did not affect the total postoperative Constant-Murley scores or retear rates

A nanoparticle ink allowing the high precision visualization of tissue engineered scaffolds by MRI

Hydrogels are widely used as cell scaffolds in several biomedical applications. Once implanted in vivo, cell scaffolds must often be visualized, and monitored overtime. However, cell scaffolds appear poorly contrasted in most biomedical imaging modalities such as magnetic resonance imaging (MRI). MRI is the imaging technique of choice for high-resolution visualization of low-density, water-rich tissues. Attempts to enhance hydrogel contrast in MRI are performed with “negative” contrast agents that produce several image artifacts impeding the delineation of the implant’s contours. In this study, a magnetic ink based on ultra-small iron oxide nanoparticles (USPIONs; <5 nm diameter cores) is developed and integrated into biocompatible alginate hydrogel used in cell scaffolding applications. Relaxometric properties of the magnetic hydrogel are measured, as well as biocompatibility and MR-visibility (T1-weighted mode; in vitro and in vivo). A 2-week MR follow-up study is performed in the mouse model, demonstrating no image artifacts, and the retention of “positive” contrast overtime, which allows very precise delineation of tissue grafts with MRI. Finally, a 3D-contouring procedure developed to facilitate graft delineation and geometrical conformity assessment is applied on an inverted template alginate pore network. This proof-of-concept establishes the possibility to reveal precisely engineered hydrogel structures using this USPIONs ink high-visibility approach