Proposition of a PLM tool to support textile design: A case study applied to the definition of the early stages of design requirements

The current climate of economic competition forces businesses to adapt more than ever to the expectations of their customers. Faced with new challenges, practices in textile design have evolved in order to be able to manage projects in new work environments. After presenting a state of the art overview of collaborative tools used in product design and making functional comparison between PLM solutions, our paper proposes a case study for the development and testing of a collaborative platform in the textile industry, focusing on the definition of early stages of design needs. The scientific contributions presented in this paper are a state of the art of current PLM solutions and their application in the field of textile design; and a case study where we will present, define, and test the mock-up of a collaborative tool to assist the early stages, based on identified intermediary representations

Experimental determination of activities of FeO and Fe2O3 components in hydrous silicic melts under oxidizing conditions.

PhD Financed by the Région Centre and by the EC TMR network "Hydrous Silicate Melts"The critical role of iron on crystal-silicate liquid relationships and melt differentiation is mainly controlled by the redox conditions prevailing in magmas, but the presently available database merely constrains the thermodynamic properties of iron-bearing components in strongly reduced and anhydrous molten silicate where iron is in the ferrous form. This paper provides new standard states for pure ferrous (FeOliq) and ferric (Fe2O3liq) molten iron oxides and extends the experimental database towards oxidizing and water-bearing domains. Iron-iridium, iron-platinum alloys, magnetite or hematite were equilibrated with synthetic silicic liquids at high temperature and high pressure under controlled oxygen fugacity (fO2) to determine activity-composition relationships for FeOliq and Fe2O3liq. Between 1000 and 1300°C, the fO2 ranges from that in air to 3-log units below that of the nickel-nickel oxide buffer (NNO). Experiments were performed on both anhydrous and hydrous melts containing up to 6-wt.% water. Incorporation of water under reducing conditions increases the activity coefficient of FeOliq but has an opposite effect on Fe2O3liq. As calcium is added to system, the effect of water becomes weaker and is inverted for Fe2O3liq. Under oxidizing conditions, water has a negligible effect on both activities of FeOliq and Fe2O3liq. In contrast, changes in redox conditions dominate the activity coefficients of both FeOliq and Fe2O3liq, which increase significantly with increasing fO2. The present results combined with the previous work provide a specific database on the energetics of iron in silicate melts that cover most of the condition prevailing in natural magmas

Time-dependent changes of the electrical conductivity of basaltic melts with redox state

International audienceThe electrical conductivity of basaltic melts has been measured in real-time after fO2 step-changes in order to investigate redox kinetics. Experimental investigations were performed at 1 atm in a vertical furnace between 1200°C and 1400°C using air, pure CO2 or CO/CO2 gas mixtures to buffer oxygen fugacity in the range 10-8 to 0.2 bars. Ferric/ferrous ratios were determined by wet chemical titrations. A small but detectable effect of fO2 on the electrical conductivity is observed. The more reduced the melt, the higher the conductivity. A modified Arrhenian equation accounts for both T and fO2 effects on the electrical conductivity. We show that time-dependent changes in electrical conductivity following fO2 step-changes monitor the rate of Fe2+/Fe3+ changes. The conductivity change with time corresponds to a diffusion-limited process in the case of reduction in CO-CO2 gas mixtures and oxidation in air. However, a reaction at the gas-melt interface probably rate limits oxidation of the melt under pure CO2. Reduction and oxidation rates are similar and both increase with temperature. Those rates range from 10-9 to 10-8m2/s for the temperature interval 1200-1400°C and show activation energy of about 200kJ/mol. The redox mechanism that best explains our results involves a cooperative motion of cations and oxygen, allowing such fast oxidation-reduction rates

Narrow loophole for H2-dominated atmospheres on habitable rocky planets around M dwarfs

Habitable rocky planets around M dwarfs that have H2-dominated atmospheres, if they exist, would permit characterizing habitable exoplanets with detailed spectroscopy using JWST, owing to their extended atmospheres and small stars. However, the H2-dominated atmospheres that are consistent with habitable conditions cannot be too massive, and a moderate-size H2-dominated atmosphere will lose mass to irradiation-driven atmospheric escape on rocky planets around M dwarfs. We evaluate volcanic outgassing and serpentinization as two potential ways to supply H2 and form a steady-state H2-dominated atmosphere. For rocky planets of 1-7 Earth mass and early, mid, and late M dwarfs, the expected volcanic outgassing rates from a reduced mantle fall short of the escape rates by >~1 order of magnitude, and a generous upper limit of the serpentinization rate is still less than the escape rate by a factor of a few. Special mechanisms that may sustain the steady-state H2-dominated atmosphere include direct interaction between liquid water and mantle, heat-pipe volcanism from a reduced mantle, and hydrodynamic escape slowed down by efficient upper-atmospheric cooling. It is thus unlikely to find moderate-size, H2-dominated atmospheres on rocky planets of M dwarfs that would support habitable environments.Comment: Accepted for publication in ApJ Letter

Limestone assimilation by basaltic magmas: an experimental re-assessment and application to Italian volcanoes

International audienceThe results of an experimental study of limestone assimilation by hydrated basaltic magmas in the range 1050-1150°C, 0.1–500 MPa are reported. Alkali basalts doped with up to 19 wt% of Ca,Mg-carbonates were equilibrated in internally heated pressure vessels and the resulting phase relationships are described. The major effects of carbonate incorporation are: 1) generation of CO2-rich fluid phases; 2) change in liquidus phase equilibria; the crystallization of Ca-rich clinopyroxene is favored and the other phases (e.g. olivine, plagioclase), present in the absence of carbonate assimilation, are consumed. As a consequence of the massive clinopyroxene crystallization, the residual melt is strongly silica-depleted and becomes nepheline-normative. Compositional and mineralogical evolutions observed in Mt.Vesuvius eruptive products match those documented in our experiments with added carbonates, suggesting the possibility that carbonate assimilation increased during the last 25ka of activity. In Central-Southern Italy, carbonate assimilation at shallow levels probably superimposes on deeper source heterogeneities

Limestone assimilation and the origin of CO2 emissions at the Alban Hills (Central Italy): constraints from experimental petrology.

International audienceThe Alban Hills volcanic region (20 km south of Rome, in the Roman Province) emitted a large volume of potassic magmas (> 280 km3) during the Quaternary. Chemical interactions between ascending magmas and the ~7000-8000-m-thick sedimentary carbonate basement are documented by abundant high temperature skarn xenoliths in the eruptive products and have been frequently corroborated by geochemical surveys. In this paper we characterize the effect of carbonate assimilation on phase relationships at 200 MPa and 1150-1050°C by experimental petrology. Calcite and dolomite addition promotes the crystallization of Ca-rich pyroxene and Mg-rich olivine respectively, and addition of both carbonates results in the desilication of the melt. Furthermore, carbonate assimilation liberates a large quantity of CO2-rich fluid. A comparison of experimental versus natural mineral, glass and bulk rock compositions suggests large variations in the degree of carbonate assimilation for the different Alban Hills eruptions. A maximum of 15 wt% assimilation is suggested by some melt inclusion and clinopyroxene compositions; however, most of the natural data indicate assimilation of between 3 and 12 wt% carbonate. Current high CO2 emissions in this area most likely indicate that such an assimilation process still occurs at depth. We calculate that a magma intruding into the carbonate basement with a rate of ~1-2•106 m3/year, estimated by geophysical studies, and assimilating 3-12wt% of host rocks would release an amount of CO2 matching the current yearly emissions at the Alban Hills. Our results strongly suggest that present CO2 emissions in this region are the shallow manifestation of hot mafic magma intrusion in the carbonate-hosted reservoir at 5-6 km depth, with important consequences for the present-day volcanic hazard evaluation in this densely populated and historical area

C-O-H fluid solubility in Haplo-basalt under reducing conditions: An experimental study

International audienceWe conducted an experimental study to constrain the C-H-O solubility and speciation in hydrous silicate melts equilibrated under reduced fO2 conditions. Haplo-basaltic glasses in the NCMAS-C-O-H system were synthesised using IHPV at 1250 °C, 200-300 MPa with variable applied fH2 so as to vary fO2. Recovered rapidly quenched glasses were characterized using various spectroscopic methods: Micro-FTIR, Raman and 13C-MAS NMR. Glass CO2 content changes from 680 to 1320 ppm between ΔFMQ-2.6 and ΔFMQ + 2.6 independently of H2O content changing from 1.3 to 4.0 wt.%. Recent thermodynamic modelling of isobaric CO2-H2O solubility fails to reproduce our CO2-H2O solubility trend under reducing conditions. The lower CO2 solubility in the melt as compared to more oxidized conditions is directly correlated to the decrease of fCO2 within the fluid phase under reducing conditions. Carbonate groups (CO32-), OH- and H2Omol are the volatile species in the glasses. No evidence for CH4, carbides or organic compounds was observed. 13C MAS NMR analysis suggests that several carbonate units are coexisting in the glasses. {1H} 13C-CPMAS NMR suggests that all CO32- units are surrounded by OH groups. Those environments appear to slightly change with changing fO2 conditions suggesting different degree of hydrogenation in the vicinity of the carbonate groups. Our data show that the presence of a significant amount of dissolved does not increase the solubility of species such as CO or CH4. In other words, such species remain insoluble in basaltic melts, as established under dry conditions. Altogether, our CO2 solubility results show that a wet but reduced basalt will degass more C-species than if oxidized, owing to the lower prevailing fCO2 and insoluble character of CO. The presence of an important fraction of CO in the fluid phase will have a large impact on the primitive atmospheric compositions of Mars and the Earth

A model for the activity of silica along the carbonatite-kimberlite-mellilitite-basanite melt compositional joint

International audienceCarbon dioxide and water, being present in the Earth’s mantle at concentration levels of tens to hundreds of ppm, greatly lower the peridotite solidus temperature and drastically modify the composition of produced melts. The presence of CO2 produces silica-poor, carbonate-rich liquids at the onset of melting, and these liquids shift toward silica rich compositions as the degree of melting increases. Numerous geochemical observations and experimental studies have revealed the complexity of the transition between carbonate-rich and silicate-rich melts. It is characterized by a strongly non-linear evolution and, under specific conditions, by immiscibility. To better constrain this transition, we have used the thermodynamic activity of silica as a probe of the mixing properties between molten carbonate and molten silicate. The activity of silica (image) was calculated for a large number of experimental liquids from two equilibria: olivine-orthopyroxene-melt and immiscible silicate-rich melt-carbonate-rich melt (491 data points ranging from 1 to 14 GPa and 1090 to 1800°C). We modeled image during incipient melting of the peridotite in presence of CO2 with a generalized Margules function. Our model well reproduces the silica activity–composition relationships of the experimental database, and can be used to predict the silica content of the melts coexisting with olivine and orthopyroxene. We show that water content and Ca/Mg ratio in the melts have an important influence on the image. In contrast to a recent empirical model (Dasgupta et al., 2013), the analysis of the experimental database reveals that the transition from carbonate to silicate melt with decreasing depth should occur abruptly in oceanic mantle. Our model predict that carbonatitic melts with ~ 5 wt.% SiO2 can be stabilized from ~ 150 km depth, at the onset of incipient melting by “redox melting”, up to ~ 75 km, above which the liquid evolves abruptly to a carbonated silicate composition (> ~ 25 wt.% SiO2). In the cratonic mantle lithosphere, our model predicts that carbonatitic melts are prevailing up to shallow depth, and conflicts the recent model (Russell et al., 2012) of CO2-saturation triggered by orthopyroxene assimilation during kimberlite ascent

Anisotropy and crystal plasticity study of fcc polycrystalline Ni by nanoindentation

National audienceL'objectif de l'étude est de mettre en lumière l'anisotropie des matériaux cristallins de type cfc aux échelles micro et nanométriques. Des résultats numériques et expérimentaux de nanoindentation sont présentés. Les essais expérimentaux ont été réalisés sur un échantillon de nickel polycristallin, avec un indenteur de type Berkovich. Les simulations ont été menées sous le code éléments finis ZEBULON, en y intégrant un modèle de plasticité cristalline en grande déformation. Trois directions cristallographiques principales, correspondant à trois grains présentant ces mêmes directions , ont été choisies comme axe d'indentation, à savoir [001], [101] et [111]. Les empreintes ont été analysées au microscope à force atomique (AFM). La topographie de la surface autour des empreintes a révélé des lignes de glissement associées aux différents systèmes activés, ainsi que des remontées de matière (bourrelets) fortement anisotropes et non-symétriques, dépendantes de l'orientation du cristal par rapport à l'indenteur. Ces observations sont en accord avec les résultats des simulations numériques. L'effet de l'orientation de l'indenteur dans chacun des plans d'indentation a également été étudié expérimentalement et numériquement

Methodological re-evaluation of the electrical conductivity of silicate melts

International audienceElectrical impedance measurements in the laboratory on silicate melts are used to interpret magnetotelluric anomalies. On the basis of 2- and 4-electrode measurements, we show that the influence of the electrodes of the 2-electrode system on the measured resistivity can be of significant importance for low-resistivity melts and increases with temperature. At 1400 °C, the resistivity of very conductive melts measured with two electrodes can reach six times the resistivity value measured with four electrodes. A short-circuit experiment is needed to correct the 2-electrode data. Electrodes contribution is also estimated for samples from other studies, for which the resistance of the electrical cell can be as high as the resistance of the sample. A correction of the resistivity data from the literature is proposed and values of the corresponding Arrhenian parameters are recommended