Near-Fatal Multiple Organ Dysfunction Syndrome Induced by Plasmodium malariae

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Transient weakening during the granulite to eclogitetransformation within hydrous shear zones (Holsnøy, Norway

International audienceIn Holsnøy (Bergen Arcs, Norway), metastable granulite facies anorthosite rocks are partiallyeclogitised within hydrous shear zones, that have been interpreted as widening over time withfluid influx and strain. We here present a detailed petrological description of metre-scale shearzones from this area. The granulite protolith (originally plagioclase + garnet + two pyroxenes) istransformed into an albite + zoisite + garnet + clinopyroxene assemblage within a few tens ofcentimetres of the shear zones. The outer edge of the shear zones consists in a fine-grainedheterogeneous assemblage of omphacite + zoisite + kyanite + garnet + phengite ± albite ± quartz.An eclogite composed of coarser omphacite + kyanite + garnet + zoisite + phengite quartz formsthe core of the shear zones. As the shear zones widened over time, this lateral evolution from theedge to the core of the shear zones reflects the temporal evolution of the granulite from thebeginning to the end of the eclogitisation reaction. The outer omphacite + zoisite + kyanite +garnet + phengite ± albite ± quartz assemblage therefore represents a transient eclogite faciesassemblage. This transient assemblage appears to be mechanically weaker than both the startinggranulite and the final eclogite, based on field and petrological findings. We investigate the impactof transient weakening during syn-tectonic metamorphism using a one-dimensional numericalmodel of a fluid-fluxed, reacting shear zone. Our numerical model shows that transient weakeningis required to explain the field and petrological data. Furthermore, we show that, while fluidinfiltration was predominantly responsible for the widening of the shear zones, strain hardeningduring the end of the eclogitisation reactions sequence had a noticeable widening effect on theshear zones

Transient weakening during the granulite to eclogite transformation within hydrous shear zones (Holsnøy, Norway)

International audienceIn Holsnøy (Bergen Arcs, Norway), metastable granulite facies anorthosite rocks are partially eclogitised within hydrous shear zones, that have been interpreted as widening over time with fluid influx and strain. We here present a detailed petrological description of two different metre-scale shear zones from this area. Within a few tens of centimetres of each shear zone, the granulite protolith (initially plagioclase + garnet + two pyroxenes) is transformed into a albite + zoisite + garnet + clinopyroxene assemblage. The outer edge of the shear zones consists in a fine-grained heterogeneous assemblage of omphacite + zoisite + kyanite + garnet + phengite ± albite ± quartz. The core of the shear zones is an homogeneous eclogite assemblage of coarser omphacite + kyanite + garnet + zoisite + phengite ± quartz. As the shear zones widened over time, this lateral evolution from the edge to the core of the shear zones reflects the temporal evolution of the granulite from the beginning to the end of the eclogitisation reaction. The outer omphacite + zoisite + kyanite + garnet + phengite ± albite ± quartz assemblage therefore represents a transient eclogite facies assemblage. Field and petrological observations suggest that this transient assemblage is mechanically weaker than both the starting strong granulite and the final eclogite. We here investigate the impact of transient weakening during syn-tectonic metamorphism using a one-dimensional numerical model of a fluid-fluxed, reacting shear zone. We show that transient weakening is required to explain our field and petrological observations. Furthermore, although the widening of the shear zones was primarily controlled by fluid infiltration, we show that strain hardening during the end of the eclogitisation reactions sequence had a noticeable widening effect on the shear zones

Transient weakening during the granulite to eclogitetransformation within hydrous shear zones (Holsnøy, Norway

International audienceIn Holsnøy (Bergen Arcs, Norway), metastable granulite facies anorthosite rocks are partiallyeclogitised within hydrous shear zones, that have been interpreted as widening over time withfluid influx and strain. We here present a detailed petrological description of metre-scale shearzones from this area. The granulite protolith (originally plagioclase + garnet + two pyroxenes) istransformed into an albite + zoisite + garnet + clinopyroxene assemblage within a few tens ofcentimetres of the shear zones. The outer edge of the shear zones consists in a fine-grainedheterogeneous assemblage of omphacite + zoisite + kyanite + garnet + phengite ± albite ± quartz.An eclogite composed of coarser omphacite + kyanite + garnet + zoisite + phengite quartz formsthe core of the shear zones. As the shear zones widened over time, this lateral evolution from theedge to the core of the shear zones reflects the temporal evolution of the granulite from thebeginning to the end of the eclogitisation reaction. The outer omphacite + zoisite + kyanite +garnet + phengite ± albite ± quartz assemblage therefore represents a transient eclogite faciesassemblage. This transient assemblage appears to be mechanically weaker than both the startinggranulite and the final eclogite, based on field and petrological findings. We investigate the impactof transient weakening during syn-tectonic metamorphism using a one-dimensional numericalmodel of a fluid-fluxed, reacting shear zone. Our numerical model shows that transient weakeningis required to explain the field and petrological data. Furthermore, we show that, while fluidinfiltration was predominantly responsible for the widening of the shear zones, strain hardeningduring the end of the eclogitisation reactions sequence had a noticeable widening effect on theshear zones

Cellulose nanocrystals as new bio-based coating layer for improving fiber-based mechanical and barrier properties

International audienceIn this work, we explored the elaboration of new smart paper by coating fiber-based materials with CNC for possible use in packaging. Particularly, we investigated application of a 100% CNC layer onto a substrate. Mainly due to the cost and limited availability of CNC on a large scale, few studies have examined these opportunities. Several layers of CNC were deposited onto a paper material using the bar-coating process to improve relevant properties of the paper surface. Surface analyses (atomic force microscopy, scanning electron microscopy, and transmission electron microscopy) were performed to elucidate the CNC network at the paper surface. Structural and mechanical properties of the final materials were evaluated. Results of general interest were obtained about barrier properties. The air barrier and grease resistance improve only with the paper coated with CNC. To complete this research, a small amount of polyethylene glycol was added to reinforce the brittle CNC coating and clearly enhance barrier properties of the paper

Fluid-pressure induced eclogitisation of a dry granulite: Insights from Hydro-Chemical model

International audienceEclogitization constitutes one of the most emblematic transformations in continental subduction zones, where conversion of initially dry lower crustal rocks into eclogite facies rocks correlates with the occurrence of seismogenic events. This reaction is generally considered to occur at high pressure conditions during hydration of dry granulite. Several models using « ad hoc » diffusion equation exist to model this hydration process and the consequences of reaction-induced changes in terms of rheology and density. However, to our knowledge, there is no quantitative model allowing to physically explain how fluids propagate inside a dry rock (i.e. with no porosity at all) and how reaction-induced alteration front widens over time. In this study, we therefore propose a new fully coupled hydro-chemical model wherein a two-phase flow model is coupled with the eclogitization reaction. We use a mass conservative approach, solving total mass and solid mass equations, in a closed isothermal system. Fluid and solid densities are calculated with lookup tables from equilibrium thermodynamics. Our model shows that a fluid pressure pulse generates a pressure gradient that can be associated with the densification reaction when the pressure required for the eclogitization is reached. This reaction generates a large increase in porosity (0 to ~16%) and subsequent porous fluid flow inside the initially dry granulite. This process is then sustained as long as the fluid pulse is maintained, and ends shortly after the fluid pressure pulse stops. However, high pressure within the reacted area can persist for a long period of time. A parametric study allowing to constrain both the duration and the widening of the reaction area is proposed as well as an application to the emblematic case study of the eclogitized granulites of Holsnoy (Bergen Arcs, Norway)

Inkjet printing of nanocellulose–silver ink onto nanocellulose coated cardboard

International audienceCellulose nanocrystals (CNC) have recently been used in the field of flexible electronics. The present work proposes to evaluate the contribution of CNC in the inkjet printing of silver conductive tracks. The potential of CNC to enhance both ink and substrate properties for printed electronics application was evaluated. First, CNC potential to be used as a scaffold for silver nanoparticles production in a compatible silver inkjet ink was evaluated. It has been found that the CNC dispersing properties, combined to their nanometrical rod-shape, allowed producing conductive suspensions at very low silver content comparing to classical silver ink. Inkjet printing of the CNC–silver suspension was then investigated on several substrates. Among these substrates, CNC coated cardboard has been studied to propose a new alternative for the printing of conductive tracks onto a porous substrate like cardboard. It appears that the CNC coating significantly limits the ink diffusion into the porous substrate by modification of the ink drop absorption kinetics, leading to the printing of well-defined conductive patterns. By using CNC in both ink formulation and substrate pre-treatment, the produced conductive patterns are nearly only composed of cellulosic material, offering new prospects in the development sustainable electronics

Adsorption versus grafting of poly(N-Isopropylacrylamide) in aqueous conditions on the surface of cellulose nanocrystals

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Eclogitisation of dry and impermeable granulite by fluid flow with reaction-induced porosity: insights from hydro-chemical modelling

International audienceEclogitisation is a major metamorphic process of continental subduction zones, where transformation of dry lower crustal rocks into eclogites seem to correlate with seismogenic events. Eclogitisation can occur at high pressure during hydration of granulite, but the physical processes controlling the hydration of dry, impermeable granulite remain poorly understood. Here, we present a new fully coupled hydro-chemical model of a non-deforming porous rock which undergoes metamorphic reactions in response to fluid pressure variations. Conservation equations for total and solid mass are solved, and fluid and solid densities are calculated with look-up tables computed from models relying on equilibrium thermodynamics. Our model shows that a fluid pressure pulse generates a pressure gradient that causes densification when the pressure required for eclogitisation is reached. The reaction generates porosity and subsequent porous fluid flow into the initially non-porous impermeable granulite. This process lasts as long as the pressure pulse is maintained, but high pressure within eclogite can persist for a longer time. The hydration front propagates tens of centimetres into the granulite in the order of weeks to months. We show that propagation of a hydration-reaction front is effectively a diffusive process, with diffusivity in the order of 10 −9 m 2 •s −1 for eclogitisation as in Holsnøy, Norway. Reactive hydration of impermeable granulite is possible because its solid density is smaller than that of eclogite. We discuss the application of our model for eclogitisation and also for other reactions for which hydration of impermeable rock is possible

Crater depth statistics: constraining obliteration rates from secondary clusters of Mojave crater

International audienceCrater statistics based on size frequency distribution have been correlated with the age of planets' surfaces. We propose to widen statistical analysis of craters using not only diameter but also crater depths. We briefly present a calibrated method that quickly measures the depth of craters and provide a dataset that is large enough to perform statistical analyses. We use this method to study the evolution for depth of several secondary clusters of the Martian crater Mojave. Our method shows that the depth to diameter ratio (D/d) is not constant but varies with the diameter. This brings a new perspective on crater depth distribution