Measurements of atmospheric and oceanic CO2 in the tropical Atlantic : 10 years after the 1982-1984 FOCAL cruises

Measurements of CO2 parameters in and over the tropical Atlantic ocean have been made during the CITHER 1 cruise (January to March 1993). These observations are compared to the results obtained a decade earlier in the same area during the FOCAL experiment (1982-1984). The increase of atmospheric CO2 (1.3 to 1.5 ppm yr-1) is in agreement with the secular trend. The variation of CO2 fugacity, fCO2, in surface seawater is analysed and compared with variations of hydrographic conditions. The apparent increase of ocean surface fCO2 is somewhat higher than the atmospheric increase: during the 9-year period, the apparent increase of oceanic fCO2 is found to range from 22.5 to 24.9 µatm. A new estimate of air-sea CO2 flux in the Atlantic equatorial belt indicates that the oceanic source is enhanced in 1993 compared to 1984. An interannual change in total inorganic carbon, TCO2, through the accumulation of CO2 in the mixed layer is assessed and analysed in comparison with the fCO2 increase. The agreement between the evolutions of the two parameters of the oceanic CO2 system is acceptable by taking into account the uncertainties to estimate these evolutions. (Résumé d'auteur

Breakthrough in basin modeling using time/space frame

International audienceA new way to model basins that couples the new space-time mathematical framework (defined as the UVT transform) and 3D restoration allows for easy and realistic construction of 4D models. Using models built with the UVT transform, basin modelers will not only include faults and erosional surface properly in all structural settings, but also restore them using a 3D geomechanical finite element engine to model the proper paleo-basin geometries. As the UVT model is being restored, a "hybrid" grid carrying the static and dynamic properties is fully restored. The basin simulation software then takes all the time-dependent geological models and performs its computations on the 4D grid. The goals of basin modeling are to find out whether the oil window was reached, to locate possible traps, and to estimate the volume and quality of hydrocarbons initially generated, migrated, and trapped, as well as to estimate pressure and temperatures in the reservoir (Rudkiewicz et al., 2000). To achieve this, a full subsurface geologic model must be constructed and restored from the source rock to the current topography. Currently, a 4D basin model is a simple horizon based layer cake grid where faults are not represented explicitly as discontinuities. The reconstruction through time is based on the vertical back-stripping of layers. This is limited because the displacement of the blocks along the fault planes cannot be modeled and the material on both sides of reverse faults cannot be represented. The estimation of migration paths across faults can be inaccurate especially in compressive basins or in extensive basins with long offset listric faults.In addition to the limitations in properly representing the model at a given time step, the evolution of the basin as a function of time is done through the simple back-stripping and flattening of layers. So, this paleo-basin geometry can be inaccurate

Modelling the experimental electron density: only the synergy of various approaches can tackle the new challenges

This is an open-access article distributed under the terms of the Creative Commons Attribution Licence.Electron density is a fundamental quantity that enables understanding of the chemical bonding in a molecule or in a solid and the chemical/physical property of a material. Because electrons have a charge and a spin, two kinds of electron densities are available. Moreover, because electron distribution can be described in momentum or in position space, charge and spin density have two definitions and they can be observed through Bragg (for the position space) or Compton (for the momentum space) diffraction experiments, using X-rays (charge density) or polarized neutrons (spin density). In recent years, we have witnessed many advances in this field, stimulated by the increased power of experimental techniques. However, an accurate modelling is still necessary to determine the desired functions from the acquired data. The improved accuracy of measurements and the possibility to combine information from different experimental techniques require even more flexibility of the models. In this short review, we analyse some of the most important topics that have emerged in the recent literature, especially the most thought-provoking at the recent IUCr general meeting in Montreal.PM thanks the Swiss National Science foundation (Project 160157) for financial support. CL and NC are grateful to Universite de Lorraine, Agence Nationale de la recherche and CNRS, for instrumental and financial support. JMG thanks CentraleSupélec, ANR and CNRS for financial support.Peer Reviewe

Tri-μ-oxido-bis­[(5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)niobium(V)]

In the title dinuclear NbV compound, [Nb2(C44H28N4)2O3], each Nb atom is seven-coordinated with three bridging O atoms and four N atoms from a chelating tetra­phenyl­porphyrinate anion. The Nb—O bond lengths range from 1.757 (6) to 2.331 (6) Å, and the average (niobium–pyrrole N atom) distance is 2.239 Å. In the dinuclear mol­ecule, the Nb⋯Nb separation is 2.8200 (8) Å, and the dihedral angle between the two porphyrinate mean planes is 5.4 (1)°. Weak inter­molecular C—H⋯π inter­actions are present in the crystal structure

Mechanical characterisation of alkali activated clay - based geopolymer binder made out of gravel wash mud

One of the most promising cement alternatives are geopolymer cements. The term “geopolymer” was mentioned for the first time by Davidovits1 and classifies all forms of inorganic polymeric material synthesised by chemical reaction of aluminosilicates and an alkaline activating solution. The production of geopolymer binder comprises in two main procedures: calcination and geopolymerisation. The synthesised geopolymer shows interesting characteristics like good mechanical properties, high strength and good durability

Risk assessment-led characterisation of the SiteChar UK North Sea site for the geological storage of CO2

Risk assessment-led characterisation of a site for the geological storage of CO2 in the UK northern North Sea was performed for the EU SiteChar research project as one of a portfolio of sites. Implementation and testing of the SiteChar project site characterisation workflow has produced a ‘dry-run’ storage permit application that is compliant with regulatory requirements. A site suitable for commercial-scale storage was characterised, compatible with current and future industrial carbon dioxide (CO2) sources in the northern UK. Pre-characterisation of the site, based on existing information acquired during hydrocarbon exploration and production, has been achieved from publicly available data. The project concept is to store captured CO2 at a rate of 5 Mt per year for 20 years in the Blake Oil Field and surrounding Captain Sandstone saline aquifer. This commercial-scale storage of 100 Mt CO2 can be achieved through a storage scenario combining injection of CO2 into the oil field and concurrent water production down-dip of the field. There would be no encroachment of supercritical phase CO2 for more than two kilometres beyond the field boundary and no adverse influence on operating hydrocarbon fields provided there is pressure management. Components of a storage permit application for the site are presented, developed as far as possible within a research project. Characterisation and technical investigations were guided by an initial assessment of perceived risks to the prospective site and a need to provide the information required for the storage permit application. The emphasis throughout was to reduce risks and uncertainty on the subsurface containment of stored CO2, particularly with respect to site technical performance, monitoring and regulatory issues, and effects on other resources. The results of selected risk assessment-led site characterisation investigations and the subsequent risk reassessments are described together with their implications for the understanding of the site. Additional investigations are identified that could further reduce risks and uncertainties, and enable progress toward a full storage permit application. Permit performance conditions are presented as SiteChar-recommended useful tools for discussion between the competent authority and operator

Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand

A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand.Gomez Garcia, Carlos Jose, [email protected]

European Lung Cancer Working Party Clinical Practice Guidelines Non-small Cell Lung Cancer: II. Unresectable Non-metastatic Stages

The present guidelines on the management of unresectable non-metastatic non-small cell lung cancer (NSCLC) were formulated by the ELCWP in October 2005. They are designed to answer the following eight questions: 1) Is chest irradiation curative for NSCLC? 2) What are the contra-indications (anatomical or functional) to chest irradiation? 3) Does the addition of chemotherapy add an advantage to radiotherapy? 4) Does the addition of radiotherapy add an advantage to chemotherapy? 5) Is irradiation as effective as surgery for marginally resectable stage III? 6) How to best combine chemotherapy with radiotherapy: sequentially, concomitantly, as consolidation, as induction, as radiosensitiser? 7) In case of too advanced locoregional disease, is there a role for consolidation (salvage) local treatment (surgery or radiotherapy) after induction chemotherapy? 8) In 2005, what are the technical characteristics of an adequate radiotherapy

European Lung Cancer Working Party. Clinical Practice Guidelines. Small Cell Lung Cancer: V. Extensive disease

The present guidelines on the management of extensive disease small cell lung cancer (SCLC) were formulated by the ELCWP in October 2007. They are designed to answer the following nine questions: 1) What is the definition of extensive disease? 2)What are the active drugs? 3) What is the best induction regimen? 4) Is there a role for maintenance chemotherapy? 5) Is there a role for dose-intensive chemotherapy? 6) Is there a role for the use of haemopoietic growth factors and stem cells support? 7) Is there a role for alternating or sequential chemotherapy? 8) Is there a role for biological treatments? 9) Is there a place for second-line chemotherapy