Comparison of phosphor screen autoradiography and micro-pattern gas detector based autoradiography for the porosity of altered rocks

This study aims to further develop the C-14-PMMA porosity calculation method with a novel autoradiography technique, the Micro-pattern gas detector autoradiography (MPGDA). In this study, the MPGDA is compared with phosphor screen autoradiography (SPA). A set of rock samples from Martinique Island exhibiting a large range of connected porosities was used to validate the MPGDA method. Calculated porosities were found to be in agreement with ones from the SPA and the triple-weight method (TW). The filmless nature of MPGDA as well as straightforward determination of C-14 radioactivity from the source rock makes the porosity calculation less uncertain. The real-time visualization of radioactivity from C-14 beta emissions by MPGDA is a noticeable improvement in comparison to SPA.Peer reviewe

Behavior of Cs in Grimsel granodiorite: sorption on main minerals and crushed rock

In this study the sorption of cesium was investigated on four different minerals; quartz, plagioclase, potassium feldspar and biotite as well as granodiorite obtained from the Grimsel test site in Switzerland. The experiments were conducted in the presence of the weakly saline Grimsel groundwater simulant by determining the distribution coefficients using batch sorption experiments and PHREEQC-modelling across a large concentration range. In addition, the purity of the minerals was measured by XRD and the specific surface areas by BET method using krypton. The distribution coefficients of cesium were largest on biotite (0.304 +/- 0.005 m(3)/kg in 10(-8) M). Furthermore, the sorption of cesium on quartz was found to be negligibly small in all investigated concentrations and the sorption of cesium on potassium feldspar and plagioclase showed similar behavior against a concentration isotherm with distribution coefficients of 0.0368 +/- 0.0004 m(3)/kg and 0.18 +/- 0.04 m(3)/kg in 10(-8) M. Finally, cesium sorption behavior on crushed granodiorite followed the trend of one of its most abundant mineral, plagioclase with distribution coefficient values of 0.107 +/- 0.003m(3)/kg in 10-8 M. At low concentrations (< 1.0 . 10(-6) M) cesium was sorbed on the frayed edge sites of biotite and once these sites are fully occupied cesium sorbs additionally to the Type II and Planar sites. As a consequence, the sorption of cesium on biotite is decreased at concentrations > 1.0 . 10(-6) M. Secondly cesium sorption on potassium feldspar and plagioclase showed similar non-linear behavior with varying concentration. The results were used to assist the interpretation of cesium diffusion process in the 2.5 year in-situ experiment carried out in the underground laboratory at Grimsel test site in Switzerland (2007-2009)

Behavior of Cs in Grimsel granodiorite: sorption on main minerals and crushed rock

In this study the sorption of cesium was investigated on four different minerals; quartz, plagioclase, potassium feldspar and biotite as well as granodiorite obtained from the Grimsel test site in Switzerland. The experiments were conducted in the presence of the weakly saline Grimsel groundwater simulant by determining the distribution coefficients using batch sorption experiments and PHREEQC-modelling across a large concentration range. In addition, the purity of the minerals was measured by XRD and the specific surface areas by BET method using krypton. The distribution coefficients of cesium were largest on biotite (0.304 +/- 0.005 m(3)/kg in 10(-8) M). Furthermore, the sorption of cesium on quartz was found to be negligibly small in all investigated concentrations and the sorption of cesium on potassium feldspar and plagioclase showed similar behavior against a concentration isotherm with distribution coefficients of 0.0368 +/- 0.0004 m(3)/kg and 0.18 +/- 0.04 m(3)/kg in 10(-8) M. Finally, cesium sorption behavior on crushed granodiorite followed the trend of one of its most abundant mineral, plagioclase with distribution coefficient values of 0.107 +/- 0.003m(3)/kg in 10-8 M. At low concentrations (< 1.0 . 10(-6) M) cesium was sorbed on the frayed edge sites of biotite and once these sites are fully occupied cesium sorbs additionally to the Type II and Planar sites. As a consequence, the sorption of cesium on biotite is decreased at concentrations > 1.0 . 10(-6) M. Secondly cesium sorption on potassium feldspar and plagioclase showed similar non-linear behavior with varying concentration. The results were used to assist the interpretation of cesium diffusion process in the 2.5 year in-situ experiment carried out in the underground laboratory at Grimsel test site in Switzerland (2007-2009)

Coupling of chemical and hydromechanical properties in bentonite:a new reactive transport model

Abstract The reactive transport framework ORCHESTRA was used to implement a dual porosity reactive transport system that accounts for mechanical processes relevant for confined swelling clays at full saturation. The new implementations are based on water retention data generated by molecular dynamics simulations, and on fundamental mechanical formulations. The code predicts and fully couples porewater chemistry, exchanger population, diffusive transport, mineral reactions, volume fractions of the free and Donnan porosity domains, and swelling pressure. The chemomechanical predictions were compared with experimental measurements of swelling pressure and d-value of the clay in different chemical environments. A simulation of bentonite in contact with a constant concentration reservoir demonstrates the performance of the new model approach. It can be used to model interactions of bentonite with different groundwaters or cement and steel

The multidimensionality of welfare state attitudes:A European cross-national study

When evaluating the various aspects of the welfare state, people assess some aspects more positively than others. Following a multidimensional approach, this study systematically argues for a framework composed of seven dimensions of the welfare state, which are subject to the opinions of the public. Using confirmatory factor analyses, this conceptual framework of multidimensional welfare attitudes was tested on cross-national data from 22 countries participating in the 2008 European Social Survey. According to our empirical analysis, attitudes towards the welfare state are multidimensional; in general, people are very positive about the welfare state’s goals and range, while simultaneously being critical of its efficiency, effectiveness and policy outcomes. We found that these dimensions relate to each other differently in different countries. Eastern/Southern Europeans combine a positive attitude towards the goals and role of government with a more critical attitude towards the welfare state’s efficiency and policy outcomes. In contrast, Western/Northern Europeans’ attitudes towards the various welfare state dimensions are based partly on a fundamentally positive or negative stance towards the welfare state