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    3D pore scale analysis of limestone matrix dissolution in CO2 EOR and geosequestration
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    Abstract:
    CO2 injection into carbonate reservoirs for CO2 enhanced oil recovery (EOR) and carbon dioxide geosequestration is a key technique to enhanced oil / gas production and mitigate anthropogenic greenhouse gas emissions. However, the carbonate rock is chemically sensitive as reacts when exposed to the acidic fluid (which is created by the CO2-saturated brine), results the formation dissolved. And such reactive transport processes are only poorly understood, particularly at the 3D micrometre scale. We thus used the novel microCT in-situ core flooding system and imaged a heterogeneous Savonnières limestone core sample before and after flooding with dead brine and CO2- saturated brine at representative reservoir condition (323 K / 50°C temperature, 15 MPa confining pressure, 10 MPa pore pressure) in-situ at high resolutions (3.43 µm and 1.25 μm voxel size) in 3D. After the imaging processing such as filter and segmentation, we indeed observed the carbonate rock matrix partially dissolved, consistent with the total porosity, effective porosity and permeability significantly increased. We also find such dissolution was confined to the original flow channels and inlet points.
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    Matrix (chemical analysis)
    'Disintegration' and 'dissolution' of solid drug dosage forms are considered as partial processes of drug liberation. Besides the (apparent) disintegration time that is determined in the official disintegration tester, there is a second (intrinsic) disintegration time which can be deduced from the experimental dissolution data, but shows only limited correlation with the former. Various methods for the graphical resolution of dissolution data and the calculation of the intrinsic disintegration time therefrom are discussed. For the simultaneous determination of disintegration and dissolution, the approved rotating flask method is recommended.
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    The dissolution of minerals in water is typically studied on macroscopic length- and time-scales, by detecting dissolution products in bulk solution and deducing reaction rates from model assumptions. Here, we report a direct, real-time measurement of silica dissolution, by monitoring how dissolution changes the first few interfacial layers of water in contact with silica, using surface-specific spectroscopy. We obtain direct information on the dissolution kinetics of this geochemically relevant mineral. The interfacial concentration of dissolution products saturates at the level of the solubility limit of silica (~millimolar) on the surprisingly short timescale of tens of hours. The observed kinetics reveal that the dissolution rate increases substantially with progressing dissolution, suggesting that dissolution is an auto-catalytic process.
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    Abstract Thorium oxide is poorly soluble: unlike uranium oxide, concentrated nitric acid medium is not sufficient to get quantitative dissolution. Addition of small amounts of fluoride is required to achieve thorium oxide total dissolution. The effect of several parameters on thorium oxide dissolution in order to optimize the dissolution conditions is reported in this paper. Thus the influence of solid characteristics, dissolution method, temperature and composition of dissolution medium on ThO 2 dissolution rate has been studied. No complexing agents tested other than fluoride allows total dissolution. Beyond a given HF concentration a decrease of the dissolution rate is observed due to the formation of a precipitate at the solid/solution interface. It was demonstrated by XPS measurements that this precipitate is constituted of thorium fluoride (ThF 4 ) formed during the ThO 2 dissolution. The low concentration of HF required to achieve a total dissolution and the activation energy value measured tends to show a catalytic effect of HF on the dissolution process.
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    In this paper the theoretical background of dissolution determining the oral administration, the physicochemical and physiological factors influencing the rate of dissolution, the relation between solubility and dissolution, the most important pharmacopoeial and miniaturized dissolution measurements and finally the dissolution in biorelevant media are reviewed.
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    The nationally-recognized Susquehanna Chorale will delight audiences of all ages with a diverse mix of classic and contemporary pieces. The ChoraleAƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚¢AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚€AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚™s performances have been described as AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚¢AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚€AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚œemotionally unfiltered, honest music making, successful in their aim to make the audience feel, to be moved, to be part of the performance - and all this while working at an extremely high musical level.AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚¢AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚€AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚ƒAƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚ƒAƒÂƒA‚‚AƒÂ‚A‚‚AƒÂƒA‚ƒAƒÂ‚A‚‚AƒÂƒA‚‚AƒÂ‚A‚ Experience choral singing that will take you to new heights!
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