Quantification of CO2 generation in sedimentary basins through carbonate/clays reactions with uncertain thermodynamic parameters

We develop a methodological framework and mathematical formulation which yields estimates of the uncertainty associated with the amounts of CO2generated by Carbonate-Clays Reactions (CCR) in large-scale subsurface systems to assist characterization of the main features of this geochemical process. Our approach couples a one-dimensional compaction model, providing the dynamics of the evolution of porosity, temperature and pressure along the vertical direction, with a chemical model able to quantify the partial pressure of CO2resulting from minerals and pore water interaction. The modeling framework we propose allows (i) estimating the depth at which the source of gases is located and (ii) quantifying the amount of CO2generated, based on the mineralogy of the sediments involved in the basin formation process. A distinctive objective of the study is the quantification of the way the uncertainty affecting chemical equilibrium constants propagates to model outputs, i.e., the flux of CO2. These parameters are considered as key sources of uncertainty in our modeling approach because temperature and pressure distributions associated with deep burial depths typically fall outside the range of validity of commonly employed geochemical databases and typically used geochemical software. We also analyze the impact of the relative abundancy of primary phases in the sediments on the activation of CCR processes. As a test bed, we consider a computational study where pressure and temperature conditions are representative of those observed in real sedimentary formation. Our results are conducive to the probabilistic assessment of (i) the characteristic pressure and temperature at which CCR leads to generation of CO2in sedimentary systems, (ii) the order of magnitude of the CO2generation rate that can be associated with CCR processes

TERRISCOPE: AN OPTICAL REMOTE SENSING RESEARCH PLATFORM USING AIRCRAFT AND UAS FOR THE CHARACTERIZATION OF CONTINENTAL SURFACES

ONERA is developing TERRISCOPE, a new platform to characterize the environment and the continental surfaces by optical remote sensing using manned aircrafts and UAS (Unmanned Airborne System). The objective of TERRISCOPE is to make available to the scientific community combinations of optical measurements remotely sensed with the best level state-of-the-art sensors. Different kinds of sensors have already been acquired or are still being acquired: Hyperspectral sensors (0.5–2.5 μm range), visible high resolution cameras, multispectral infrared cameras and airborne laser scanners. Each sensor is declined in two versions: one high performance for manned aircrafts and one more compact for UAS. This paper describes the whole equipment, and presents the main characteristics and performances of the carriers, the sensors and the processing chain. Possible sensors combinations on airplanes and UAS are also presented, as well as preliminary results

The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agroecosystem services across Europe

Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non‐crop habitats, and species’ dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7‐ and 1.4‐fold respectively. Arable‐dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield‐enhancing ecosystem services

Advances, Challenges and Opportunities in 3D CMOS Sequential Integration

3D sequential integration enables the full use of the third dimension thanks to its high alignment performance. In this paper, we address the major challenges of 3D sequential integration: in particular, the control of molecular bonding allows us to obtain pristine quality top active layer. With the help of Solid Phase Epitaxy, we can match the performance of top FET, processed at low temperature (600°C), with the bottom FET devices. Finally, the development of a stable salicide enables to retain bottom performance after top FET processing. Overcoming these major technological issues offers a wide range of applications

Calcul de la pluie sur le bassin versant du lac Titicaca pendant l'Holocène

Le niveau d'un lac situé dans un bassin endoréique permet d'estimer les valeurs de précipitation en se basant sur le bilan hydrologique à l'échelle du bassin. Les niveaux du lac Titicaca (Bolivie) ont été précédemment publiés pour l'Holocène et montrent, pendant la période la plus aride, de 8 000 ans à 4 000 ans BP, que le lac avait un niveau moyen de 50 m plus bas qu'aujourd'hui. La pluie calculée associée à tels niveaux bas serait de 635 plus ou moins 50 mm/an, soit de l'ordre de 18% inférieure à la pluie actuelle (Résumé d'auteur

L'évaporation des nappes phréatiques sous climat aride est-elle indépendante de la nature du sol ?

Les données d'une vingtaine de profils isotopiques de la zone non saturée conduit à une expression du flux évaporatoire des aquifères qui est fonction de l'inverse de la profondeur du niveau piézométrique, et qui apparait indépendante de la nature des sols. La publication de mesures de succions de plus de 1000 m de la surface du sol et de conductivités hydrauliques obtenues jusqu'à de telles succions a permis de mener de nouveaux calculs qui corroborent la faible influence des caractéristiques des sols sur le flux évaporatoire des aquifères de régions arides. (Résumé d'auteur

Is the evaporation from phreatic aquifers in arid zones independent of the soil characteristics ? / L'évaporation des nappes phréatiques sous climat aride est-elle indépendante de la nature du sol ?

The approximatly 20 pulished data based on isotopic profiles of the unsaturated zone lead us to express the evaporative flx as an inverse power function of the piezometric depth below the soil surface, independently of the soil characteristics. (...) Les données d'une vingtaine de profils isotopiques de la zone non saturée conduit à une expression du flux évaporatoire des aquifères qui est fonction de l'inverse de la profondeur du niveau piézométrique, et qui apparait indépendante de la nature des sols. La publication de mesures de succions de plus de 1000 m de la surface du sol et de conductivités hydrauliques obtenues jusqu'à de telles succions a permis de mener de nouveaux calculs qui corroborent la faible influence des caractéristiques des sols sur le flux évaporatoire des aquifères de régions arides. (Résumé d'auteur