Intrusion and extrusion of water in hydrophobic mesopores

We present experimental and theoretical results on intrusion-extrusion cycles of water in hydrophobic mesoporous materials, characterized by independent cylindrical pores. The intrusion, which takes place above the bulk saturation pressure, can be well described using a macroscopic capillary model. Once the material is saturated with water, extrusion takes place upon reduction of the externally applied pressure; Our results for the extrusion pressure can only be understood by assuming that the limiting extrusion mechanism is the nucleation of a vapour bubble inside the pores. A comparison of calculated and experimental nucleation pressures shows that a proper inclusion of line tension effects is necessary to account for the observed values of nucleation barriers. Negative line tensions of order $10^{-11} \mathrm{J.m}^{-1}$ are found for our system, in reasonable agreement with other experimental estimates of this quantity

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International audienc

Crop Phenology Modelling Using Proximal and Satellite Sensor Data

peer reviewedUnderstanding crop phenology is crucial for predicting crop yields and identifying potential risks to food security. The objective was to investigate the effectiveness of satellite sensor data, compared to field observations and proximal sensing, in detecting crop phenological stages. Time series data from 122 winter wheat, 99 silage maize, and 77 late potato fields were analyzed during 2015–2017. The spectral signals derived from Digital Hemispherical Photographs (DHP), Disaster Monitoring Constellation (DMC), and Sentinel-2 (S2) were crop-specific and sensor-independent. Models fitted to sensor-derived fAPAR (fraction of absorbed photosynthetically active radiation) demonstrated a higher goodness of fit as compared to fCover (fraction of vegetation cover), with the best model fits obtained for maize, followed by wheat and potato. S2-derived fAPAR showed decreasing variability as the growing season progressed. The use of a double sigmoid model fit allowed defining inflection points corresponding to stem elongation (upward sigmoid) and senescence (downward sigmoid), while the upward endpoint corresponded to canopy closure and the maximum values to flowering and fruit development. Furthermore, increasing the frequency of sensor revisits is beneficial for detecting short-duration crop phenological stages. The results have implications for data assimilation to improve crop yield forecasting and agri-environmental modeling

Hyperferritinémies et insulinorésistance

Introduction : Le rôle de la ferritine dans l'insulinorésistance se pose devant des cas de patients non hémochromatosiques au profil métabolique qui semble homogène.Méthode ~ description de 73 patients hyperferritinémiques idiopathiques exclusion faite des génotypes homozygotes et hétérozygotes composites pour les mutations C282Y et H63D du gène HFE. Résultats et discussion : Notre population comprend 25 femmes (âge moyen 59,5 ans) et 48 hommes (âge moyen 56,2 ans). La feffitinémie est plus élevée chez les hommes, mais ne varie pas selon l'âge, ni le statut hormonal des femmes. Le coefficient de saturation de la transferrine est normal. La ferritinémie est corréfée au taux de triglycérides et inversement corrélée au taux de HDL cholestérol. Les patientes se plaignent à 72% d'asthénie et 72% de douleurs articulaires contre 48,9% et 56,3% chez les hommes. Ce sont des polyarthralgies mécaniques quiii touchent les grosses articulations (52,1% des cas) et les petites articulations des mains et des pieds (20,6% des cas). Une forte prévalence des facteurs de risque cardiovasculaire constitutionnels contraste avec une faible prévaience des maladies cardiovasculaires avérées: 43,8% d'HTA, 61,6% d'hypercholestérolémie, 37,5% d'hypertfigJycéfidémie. 42,9% des patients sont en surpoids et 45,7% sont obèses. En fonction des critères NCEP ou IDF, la prévalence de l'obésité abdominale est de 84 et 920/a chez les femmes et de 65 et 94% chez les hommes. Selon les mêmes critères, 40 à 68% des femmes et 43,5 à 72,9% des hommes ont un syndrome métabolique. La ferritinémie est plus importante et l'insulinorésistance plus fréquente chez ces patients. Un index HOMA>2 est retrouvé chez 46% des femmes et 59% des hommes. a ferritinémie semble plus élevée dans ce sous groupe mais la significativité est limite (p=0,0693). L'index HOMA est corrélé au tour de taille, à PIMC et inversement corréfé au HDL cholestérol. 20% de nos patients sont hétérozygotes pour la mutation C282Y du gène HFE, 37% pour la mutation H63D et aucun pour la mutation S65C. Les mutations étudiées n'influent pas sur l'existence d'une insulinorésistance, ni sur la ferritinémie. Mais la prévalence de l'hétérozygotie C282Y est plus importante chez nos patients compar à une population témoin non hyperferritinémique (2D,5% versus 7%; p= 0003_ occis ratio= 3,42). Cette différence de prévalence n'est pas clairement é blie pour, les hétérozygotes H63D (37% versus 27,5%; p=0,0584). Conclusion : Nos patients hyperferritinémiques ont un morphotype commun surpoids et obésité abdominale. Les douleurs articulaires et l'asthénie ont une prévalence élevée. La moitié de la population est insulinorésistante avec des facteurs de risque associés (HTA, dyslipidémie) sans pathologie cardiovasculaire avérée. L'hyperferritinémie est associée au syndrome métabolique et à l'hétérozygôfie C282Y. L'association avec l'insulinorésistance mérite une consolidation des résultàtà,~ La ferritine acteur au témoin de l'insulinorésistance, deviendra certainement dans l'avenir un facteur prédictif du risque cardiovasculaire globalAMIENS-BU Santé (800212102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

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Crowdsourcing for agricultural applications: A review of uses and opportunities for a farmsourcing approach

Abstract Crowdsourcing, understood as outsourcing tasks or data collection by a large group of non-professionals, is increasingly used in scientific research and operational applications. In this paper, we reviewed crowdsourcing initiatives in agricultural science and farming activities and further discussed the particular characteristics of this approach in the field of agriculture. On-going crowdsourcing initiatives in agriculture were analysed and categorised according to their crowdsourcing component. We identified eight types of agricultural data and information that can be generated from crowdsourcing initiatives. Subsequently we described existing methods of quality control of the crowdsourced data. We analysed the profiles of potential contributors in crowdsourcing initiatives in agriculture, suggested ways for increasing farmers’ participation, and discussed the on-going initiatives in the light of their target beneficiaries. While crowdsourcing is reported to be an efficient way of collecting observations relevant to environmental monitoring and contributing to science in general, we pointed out that crowdsourcing applications in agriculture may be hampered by privacy issues and other barriers to participation. Close connections with the farming sector, including extension services and farm advisory companies, could leverage the potential of crowdsourcing for both agricultural research and farming applications. This paper coins the term of farmsourcing as a professional crowdsourcing strategy in farming activities and provides a source of recommendations and inspirations for future collaborative actions in agricultural crowdsourcing

The robotized laser doppler vibrometer: On the use of an industrial robot arm to perform 3D full-field velocity measurements

International audienceAn original experimental setup, dedicated to the measurement of the dynamic response of structures, is presented. Called the Robotized Laser Doppler Vibrometer (RLDV), it consists in the assembly of a fixed point Laser Doppler Vibrometer (LDV) on a 6-axis industrial robot arm. This allows to measure the 3D velocity on the surface of objects with a wide range of shapes and sizes. In comparison with commercially available solutions, it represents an affordable and versatile tool. First, the motivations and the new challenges associated to the use of a robot arm to do such experiments are discussed. Second, the different strategies implemented to overcome these difficulties are developed. A software solution is proposed. By the use of a virtual model of the experimental setup, the measurement procedure can be designed and simulated in order to preview robot motion and avoid collisions. With a small number of parameters, the good proceeding of the measurement can be insured on a fine measurement mesh. The software is completed by an interface that allows for the setting of the signal acquisition parameters. At the end, all the procedure is automated and long measurements can be achieved with a reduced supervision. To illustrate the proposed setup, an experimental application is developed. The 3D modal shapes of a curved beam are measured and compared with numerical predictions, showing an excellent correlation

3D-FDTD-based hybridisation technique for wave interaction with scatterers in layered media

International audienceA simple method for the computation of 3D scatterers remotely located from the source with layered media is presented. This domain decomposition method is based on the total-field/scattered-field formulation of the 3D finite-difference in time-domain method. The electromagnetic field along the propagation path is not directly involved; it focuses only on the electromagnetic field in the surroundings of the scatterer. The incident electromagnetic field radiated from the source is computed separately with an adaptive algorithm and then applied on the Huygens’ surface, leading to the proposed hybridisation technique

Accuracy of Norton Approximation Formulas for the Radiation of an Electric Current Element over a Homogeneous Ground

In this paper the problem of the radiation of an electric current element above a homogeneous infinite flat ground is solved with an adaptive algorithm to compute the numerical integration. This method ensures to obtain the correct values of all components of the electromagnetic field with a controlled accuracy. These values, computed in different scenes, are considered as references to analyse the approximation error in the propagation theory of Norton

Eurotherm 69

he general purpose of this work concerns the latent heat storage ( cold storage ) by encapsulated nodules of 7.7 cm in diameter containing a Phase Change aterial ( PC ) and filling a cylindrical tank ( about 2500 nodules per m ). During the storage process, a cold heat transfe r liquid flows through the tank to crystallise the PC M inside the nodules.T he stored energy is released when a hotter heat transfer liquid flows t hrough the tank to induce the melting of the PCM. We have presented a global study [1][2] of the behaviour of the tank without differentiating the nodules. But, we highlighted the difference between the storage (cooling ) and the discharge ( heating ) due to the supercooling phenomen on. As typically the velocity in the tank is relatively small ( a few mm/s ), it is possible to assume the appearance of natural convection of the coolant when the latent heat is released at the crystallisation of the PCM. So, we present a study of a single nodule surrounded by a flowing heat transfer liquid at a temperature C T lowe than the melting tempe atu e F T . At the c ystallisation, only a pa t of the nodule is solid whe eas the ema ining liquid is at F T he c ystallisation is pu sued owing to the heat flux involved by the diffe ence C F T T - his text describes a model to explain the mutual influence of the natural convection and the kinetics of crystallisation inside the nodule.