COST-G: towards a new GRACE and GRACE-FO combination

The combination service for time-variable gravity fields (COST-G) provides the full time-series of monthly GRACE gravity fields: COST-G GRACE RL01, combined in reprocessing mode, and a steadily growing time-series of monthly GRACE-FO gravity fields: COST-G GRACE-FO RL01 OP, combined on an operational basis. Both time-series are currently considered for re-combination. In case of GRACE, new high-quality time-series from Chinese analysis centers are available for combination. In case of GRACE-FO, a revision of the weighting scheme, developed in the frame of the Horizon2020 project Global Gravity-based Groundwater Product (G3P), and the availability of reprocessed GRACE-FO time-series from AIUB, CSR, GFZ, and JPL, lead to a significant improvement of the combined gravity fields. We present the preliminary re-combined GRACE and GRACE-FO time-series and quantify the differences with respect to the COST-G RL01 series in terms of signal and noise content

European Gravity Service for Improved Emergency Management

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European Gravity Service for Improved Emergency Management - Status and project highlights

European Gravity Service for Improved Emergency Management - Status and project highlight

European Gravity Service for Improved Emergency Management - Status and project highlights

European Gravity Service for Improved Emergency Management - Status and project highlight

Synclinic-anticlinic phase transition in tilted organosiloxane liquid crystals

In this paper, we considered the case of low molecular weight bimesogenic liquid crystals containing a siloxane moiety as the central part of their molecular architecture. For some of these compounds, both ferro- and antiferroelectric mesophases are present. Two distinct smectic structures can develop as a function of temperature, the first one at high temperature corresponding to a synclinic molecular arrangement with elongated molecules, and the second one at lower temperature corresponding to an anticlinic organisation with V-shaped molecules. Numerical calculations of the energy of different conformations of these bimesogenic molecules presented here indicate that there is no difference in energy between V-shaped and linear conformations regardless of the number of silicon atoms in the siloxane moiety. Thus a microscopic model of the synclinic-anticlinic phase transition is developed where the driving force is indeed a free energy difference between the two phases, and not a difference of energy between the V-shaped and linear conformations. The model explains why the anticlinic SmCA phase is more stable than the synclinic SmC one, why the synclinic SmC phase is generally the higher temperature one, and why in some organosiloxane materials the anticlinic SmCA phase is not present