Search results for "Dissolution"
showing 10 items of 333 documents
The end of the Messinian Salinity Crisis in the western Mediterranean: insights from the carbonate platforms of south-eastern Spain.
2010
International audience; How the Messinian Salinity Crisis (MSC) ended is still a matter of intense debate. The Terminal Carbonate Complex (TCC) is a late Messinian carbonate platform system that recorded western Mediterranean hydrological changes from the final stages of evaporite deposition till the advent of Lago-Mare fresh- to brackish water conditions at the very end of Messinian times. A multidisciplinary study has been carried out in three localities in south-eastern Spain to reconstruct the history of TCC platforms and elucidate their significance in the MSC. Overall, this study provides evidence that the TCC formed following a regional 4th order water level rise and fall concomitant…
Comments on the paper entitled ‘The formulation and modelling of the anodic dissolution of zinc through adsorbed intermediates’by G.G. Láng, and G. H…
2007
The points raised in the paper entitled "Comments on the paper entitled 'The formulation and modelling of the anodic dissolution of zinc through adsorbed intermediates"' have been discussed. It has been shown that, in contrast to the statements in the "Comments", most of the papers concerning the reaction schemes suggested for the interpretation of the dissolution or deposition of metals, which were considered as a support for the opinion of the Authors of the "Comments", support the views expressed in our original paper [J. Electroanal. Chem. 583 (2005) 148]. On the other hand, it has been stressed again that the criticism expressed in the original paper refers to dubious conclusions drawn…
Ellipsoid-shaped superparamagnetic nanoclusters through emulsion electrospinning.
2015
Ellipsoid-shaped nanoclusters composed of single superparamagnetic nanoparticles can be generated by emulsion electrospinning. Stretching and subsequent solvent evaporation of iron oxide loaded emulsion droplets during the emulsion electrospinning process enables the creation of such structures embedded in polymer nanofibers. Dissolution of the polymer fibers yields an aqueous dispersion of the inorganic clusters which are the first example of ellipsoid-shaped superparamagnetic nanoclusters with a high saturation magnetization (∼47 emu g(-1)).
Influence of pH and temperature on the early stage of mica alteration
2012
Mineral dissolution and precipitation reactions actively participate in controlling fluid chemistry during water–rock interaction. In this study, the changes in the biotite and muscovite basal surface nano-morphology were evaluated during interaction with fluids of different pH (pH = 1.1, 3.3 and 5.7) at different temperatures (T =2 5, 120, and 200 C). Results show that at the nanometre scale resolution of the atomic force microscope (AFM), dissolution generates etch pits with a stair-shaped pattern over the (0 0 1) surface. The flux of dissolved elements decreases when pH increases. However, at pH 5.7, a change was found in the flux after 42 h of reaction when abundant gibbsite and kaolini…
Origin of Ubiquitous Stripes at the Graphite–Water Interface
2020
The investigation of solid-liquid interfaces is pivotal for understanding processes like wetting, corrosion, and mineral dissolution and growth. The graphite-water interface constitutes a prime example for studying the water structure at a seemingly hydrophobic surface. Surprisingly, in a large number of atomic force microscopy (AFM) experiments, well-ordered stripes have been observed at the graphite-water interface. Although many groups have reported on the observation of stripes at this interface, fundamental properties and, in particular, the origin of the stripes are still under debate. Proposed origins include contamination, interplanar stacking of graphene layers, formation of methan…
Iron-clay interactions: Detailed study of the mineralogical transformation of claystone with emphasis on the formation of iron-rich T-O phyllosilicat…
2014
International audience; Iron-minerals-water interactions are of primary importance in the contexts of underground structure engineering (e.g. reactive barriers or deep geological storage) and for the understanding of secondary alteration processes in primitive meteorites. To improve our understanding of these systems, we determine the mineralogical transformations induced by the association of iron and silicates during a cooling through an experimental simulation of iron-clay interactions with a step-by-step procedure in the range of 90 degrees C to 40 degrees C. The run products and solutions are well characterised, by means of different techniques (X-ray diffraction, scanning and transmis…
La mise en sommeil d'une association n'est pas une cause de dissolution obligatoire ou facultative
1996
International audience
Mechanistic analysis and experimental verification of bicarbonate-controlled enteric coat dissolution: Potential in vivo implications
2019
Enteric coatings have shown in vivo dissolution rates that are poorly predicted by traditional in vitro tests, with the in vivo dissolution being considerably slower than in vitro. To provide a more mechanistic understanding of this, the dependence of the release properties of various enteric-coated (EC) products on bulk pH and bicarbonate molarity was investigated. It was found that, at presumably in vivo-relevant values, the bicarbonate molarity is a more significant determinant of the dissolution profile than the bulk pH. The findings also indicate that this steep relationship between the dissolution of enteric coatings and bicarbonate molarity limits those coatings' performance in vivo.…
Rapid hyperpolarization and purification of the metabolite fumarate in aqueous solution
2020
Significance Magnetic resonance imaging is hindered by inherently low sensitivity, which limits the method for the most part to observing water molecules in the body. Hyperpolarized molecules exhibit strongly enhanced MRI signals which opens the door for imaging low-concentration species in vivo. Biomolecules can be hyperpolarized and injected into a patient allowing for metabolism to be tracked in real time, greatly expanding the information available to the radiologist. Parahydrogen-induced polarization (PHIP) is a hyperpolarization method renowned for its low cost and accessibility, but is generally limited by low polarization levels, modest molecular concentrations, and contamination by…
Global charcoal mobilization from soils via dissolution and riverine transport to the oceans
2013
Dissolving Charcoal Biomass burning produces 40 to 250 million tons of charcoal per year worldwide. Much of this is preserved in soils and sediments for thousands of years. However, the estimated production rate of charcoal is significantly larger than that of decomposition, and Jaffe et al. (p. 345 ; see the Perspective by Masiello and Louchouarn ) calculate that a large fraction of the charcoal produced by fires is lost from the land through dissolution and transport to the oceans.