Systèmes de fortification de l’habitat de hauteur du Puech de Mus à Sainte-Eulalie-de-Cernon (Aveyron) au Ve s. av. J.-C.

Les recherches effectuées de 1995 à 2000 sur l’habitat de hauteur du Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron) permettent d’appréhender, pour la première fois sur les Grands Causses, l’évolution de plusieurs complexes de fortification du Ve s. av. J.-C. En moins d’un siècle, on passe d’un rempart vraisemblablement à parements internes, associant la pierre et le bois, à une enceinte palissadée, puis talutée et fossoyée dont on a étudié les grandes lignes de trois systèmes d’accès successifs. Le démantèlement par le feu de plusieurs de ces ouvrages défensifs ainsi que la présence de quelques pièces d’armement dans le niveau d’abandon évoquent manifestement des épisodes mouvementés. Les données architecturales de la première enceinte calcinée, avec ses poutrages internes, renvoient clairement à l’orbe celtique malgré la proximité du littoral languedocien.Fortification systems from the upland settlement of Puech de Mus at Sainte-Eulalie-de-Cernon (Aveyron) during the Vth century BC. The research carried out between 1995 and 2000 on the Puech de Mus hilltop settlement (Sainte-Eulalie-de-Cernon, Aveyron) allows us to appreciate for the first time the evolution of several Vth C. BC fortified sites on the Grands Causses. In under a century, there is change from a rampart, comprised of internal facing combining stone and wood, to a palisaded wall, then a ditch and bank. These three associated successive access systems have been studied. The destruction of several of these defensive works by fire, along with the presence of several pieces of armament in the abandonment levels, evokes some dramatic events. The architectural information from the first burnt wall, with its internal beams, remind us of the Celtic world despite the site’s proximity to the Languedocian coast

Wideband Mid Infrared Absorber using surface Doped Black Silicon

Black silicon (BSi) is a synthetic nanomaterial with high aspect ratio nano protrusions inducing several interesting properties such as a very large absorptivity of incident radiation. We have recently shown that heavily doping the BSi in volume enables to significantly enhance its mid infrared absorptivity and tune its spectral range of interest up to 20 micrometer. In the present letter, we explore the effect of surface doping on BSi radiative properties and it absorptance, in particular since surface doping enables reaching even larger dopant concentrations than volume doping but at more limited penetration depths. We considered 12 different wafers of BSi, fabricated with cryogenic plasma etching on n and p-type silicon wafers and doped using ion-implantation with different dopant types, dosages and ion beam energies leading to different dopant concentrations and profiles. The different wafers radiative properties, reflectance, transmittance and absorptance, are measured using Fourier transform infrared spectroscopy. We show that doping an n-type BSi wafer with Phosphorous with a dose of 10^17 atm/cm2 and an energy of 100 keV increases its absorptivity up to of 98% in the spectral range of 1-5 micrometer. We propose a simple phenomenological explanation of the observed results based on the dopant concentration profiles and the corresponding incident radiation penetration depth. Obtained results provide simple design rules and pave the way for using ion-implanted BSi for various applications such as solar energy harvesting, thermo-photovoltaics and infrared radiation sensing where both high absorptance and variable dopant concentration profiles are required

Sépultures d’enfants en bas âge dans l’agglomération du Puech de Mus à Sainte-Eulalie-de-Cernon (Aveyron) au Ve s. av. J.-C.

Les fouilles programmées menées de 1995 à 2000 sur l’oppidum caussenard du Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron), ont permis de découvrir les sépultures de sept enfants en bas-âge et les restes déplacés de trois autres. Il s’agit de deux prématurés, sept individus nés à terme et décédés dans les jours suivant la naissance, et d’un nourrisson d’environ trois mois. Le contexte est celui d’un habitat de la seconde moitié du Ve s. av. J.-C. qui connaissait une intense activité métallurgique. Chaque sépulture, chaque défunt est étudié en détail, de même que les modalités de dépôt. La synthèse de ces informations, replacées dans le contexte du sud de la France, permet d’entrevoir la manière dont les survivants percevaient les facteurs de la mortalité infantile. Elle permet aussi de mettre l’accent sur les liens éventuels entre ces très jeunes morts et l’activité de forge.Fifth century BC burials of young infants at Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron). A research excavation was carried out at the oppidum of Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron) between 1995 and 2000. Seven buried young children were found as well as the disturbed remains of three others. The group comprised two premature infants, seven babies who had gone the full-term, two who had died shortly after birth, and an infant of about three months. The context for these finds is a settlement dating to the second half of the fifth century BC where there is evidence for intense metalworking. Each burial and each individual was studied in detail as well as the form of deposit. A synthesis placing this evidence within the context of the south of France allows us to consider how these people perceived infant mortality. It also allows us to consider the possible links between these deceased infants and the forge activity

Evaluation of Zonal Detached Eddy Simulation k-ω and Scale Adaptive Simulation methods on a realistic rotor of a high-pressure compressor

In order to improve turbomachinery performances it is necessary to correctly predict secondary and transitional flows inherent to this confined environment. Secondary flows can cause additional loss and operating domain reduction. For example, tip-leakage vortex flow or corner separation flow on high pressure compressor blades lead to total pressure loss limiting turbomachinery efficiency and favoring emergence of hazardous axial instability (surge). Secondary flows often exhibit strong fluctuating behaviors and flow separations which make their prediction quite challenging, often found inaccurate with current turbulence modeling tools used during design process. One reason lies in the error on turbulent fluctuation predictions when they are entirely modeled by statistical averaging (RANS - Reynolds Average Navier-Stokes). However, more accurate methods such as Large Eddy Simulations (LES) are difficult to use at high Reynolds number due to excessive computation, treatment and storage costs. A trade-off can be found in hybrid RANS/LES methods such as ZDES (Zonal Detached Eddy Simulation) method developed at ONERA. Through the main operating mode of ZDES method, boundary layers are treated by RANS modeling on their whole thickness to avoid near-wall excessive cost of LES method which is only used away of the walls. The interface between those two sub-methods is continuous. Its RANS sub-method is based on SA turbulence model. As demonstrated by W. Riéra (Ph.D. thesis, Evaluation of the ZDES method on an axial compressor: analysis of the effects of upstream wake and throttle on the tip-leakage flow, Ecole Centrale de Lyon, 2014) the SA turbulence model used in the RANS sub-method of the current ZDES method makes difficult to predict turbomachinery flows at limit operating range because of its poor behavior near numerical surge line. A major reason is that RANS SA model tends to predict too massive or simply false flow separations, which is critical for such flows with corner flow separation. A suggested remedy is to re-based the ZDES method on a k-? Menter turbulence model which present better behavior regarding progressive flow separation prediction. Several ZDES k-? Menter method formulations have been assessed on three academic cases (a mixing layer flow, a backward facing step flow and a circular cylinder flow at Re = 3900, AIAA Aviation 2017). One of these formulations has been selected based on its capability (i) to allow the emergence and the correct development of Kelvin-Helmholtz instabilities and (ii) to ensure that boundary layers are treated by RANS modeling in their entire thickness. Alternatively to hybrid RANS/LES methods, upgraded URANS approaches are interesting tools for resolving a variable fraction of the larger scales of turbulent motions, allowing a better representation of unsteady flows than URANS methods. Among them, the Scale Adaptive Simulation (SAS) approach of has been implemented in ONERA's elsA solver with an improvement dealing with the development of instabilities within mixing layers. This study focuses on the validation of the selected ZDES k-? Menter formulation and the SAS approach on the same configuration as W. Riéra ZDES SA simulation i.e. a flow simulation of a realistic rotor of a high-pressure compressor with incoming stator wakes. Simulation is carried out on the same mesh and numerical framework as W. Riéra ones for appropriate comparison with their ZDES SA results and with experimental data

Sépultures d’enfants en bas âge dans l’agglomération du Puech de Mus à Sainte-Eulalie-de-Cernon (Aveyron) au Ve s. av. J.-C.

Les fouilles programmées menées de 1995 à 2000 sur l’oppidum caussenard du Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron), ont permis de découvrir les sépultures de sept enfants en bas-âge et les restes déplacés de trois autres. Il s’agit de deux prématurés, sept individus nés à terme et décédés dans les jours suivant la naissance, et d’un nourrisson d’environ trois mois. Le contexte est celui d’un habitat de la seconde moitié du Ve s. av. J.-C. qui connaissait une intense activité métallurgique. Chaque sépulture, chaque défunt est étudié en détail, de même que les modalités de dépôt. La synthèse de ces informations, replacées dans le contexte du sud de la France, permet d’entrevoir la manière dont les survivants percevaient les facteurs de la mortalité infantile. Elle permet aussi de mettre l’accent sur les liens éventuels entre ces très jeunes morts et l’activité de forge.Fifth century BC burials of young infants at Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron). A research excavation was carried out at the oppidum of Puech de Mus (Sainte-Eulalie-de-Cernon, Aveyron) between 1995 and 2000. Seven buried young children were found as well as the disturbed remains of three others. The group comprised two premature infants, seven babies who had gone the full-term, two who had died shortly after birth, and an infant of about three months. The context for these finds is a settlement dating to the second half of the fifth century BC where there is evidence for intense metalworking. Each burial and each individual was studied in detail as well as the form of deposit. A synthesis placing this evidence within the context of the south of France allows us to consider how these people perceived infant mortality. It also allows us to consider the possible links between these deceased infants and the forge activity

Magnetic interactions in iron superconductors: A review

High temperature superconductivity in iron pnictides and chalcogenides emerges when a magnetic phase is suppressed. The multi-orbital character and the strength of correlations underlie this complex phenomenology, involving magnetic softness and anisotropies, with Hund's coupling playing an important role. We review here the different theoretical approaches used to describe the magnetic interactions in these systems. We show that taking into account the orbital degree of freedom allows us to unify in a single phase diagram the main mechanisms proposed to explain the (\pi,0) order in iron pnictides: the nesting-driven, the exchange between localized spins, and the Hund induced magnetic state with orbital differentiation. Comparison of theoretical estimates and experimental results helps locate the Fe superconductors in the phase diagram. In addition, orbital physics is crucial to address the magnetic softness, the doping dependent properties, and the anisotropies.Comment: Invited review article for a focus issue of Comptes Rendus Physique: 26 pages, 10 figures. Revised version, as accepted. Small changes throughout the text plus new subsection (Sec. IIIE

From molecular chaperones to membrane motors: through the lens of a mass spectrometrist

Twenty-five years ago, we obtained our first mass spectra of molecular chaperones in complex with protein ligands and entered a new field of gas-phase structural biology. It is perhaps now time to pause and reflect, and to ask how many of our initial structure predictions and models derived from mass spectrometry (MS) datasets were correct. With recent advances in structure determination, many of the most challenging complexes that we studied over the years have become tractable by other structural biology approaches enabling such comparisons to be made. Moreover, in the light of powerful new electron microscopy methods, what role is there now for MS? In considering these questions, I will give my personal view on progress and problems as well as my predictions for future directions