Analytical Solution Incorporating History-Dependent Processes for Quick Assessment of Capillary Trapping During CO<Subscript>2</Subscript> Geological Storage

Carbon storage in saline formations is considered as a promising option to ensure the necessary decrease of CO₂ anthropogenic emissions. Its industrial development in those formations is above all conditioned by its safety demonstration. Assessing the evolution of trapped and mobile CO₂ across time is essential in the perspective of reducing leakage risks. In this work, we focus on residual trapping phenomenon occurring during the wetting of the injected CO₂ plume. History dependent effects are of first importance when dealing with capillary trapping. We then apply the classical fractional flow theory (Buckley–Leverett type model) and include trapping and hysteresis models; we derive an analytical solution for the temporal evolution of saturation profile and of CO₂ trapped quantity when injecting water after the gas injection (“artificial imbibition”). The comparison to numerical simulations for different configurations shows satisfactory match and justifies, in the case of industrial CO₂ storage, the assumptions of incompressible flow with no consideration of capillary pressure. The obtained analytical solution allows the quick assessment of both the quantity and the location of mobile gas left during imbibition.     

Nonlinear imaging and THz diagnostic tools in the service of Cultural Heritage

We present the use of novel nonlinear imaging, terahertz time-domain spectroscopy and imaging as powerful diagnostic tools for studies of works of art. It is shown that nonlinear imaging offers precise in-depth information, while terahertz imaging can reveal hidden objects and uncover information on highly absorbing organic compounds whose visualization is difficult in other parts of the spectrum.     

Search for scalar top quark production in p&pmacr; collisions at sqrt

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb(-1) of p&pmacr; collisions at sqrt[s] = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c(2) and scalar neutrino masses of at least 40 GeV/c(2), we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios.     

Measurement of(di)muons from heavy flavour decay in p-p collisions at 14 TeV with ALICE at the LHC

We present the performance of the ALICE muon spectrometer for measuring the charm and beauty inclusive pt differential production cross sections via single muons and unlike-sign dimuons in proton-proton collisions at(√s) = 14 TeV.     

Evidence for the Formation of Trioctahedral Clay upon Sorption of Co on Quartz

The sorption mechanism of Co on quartz at room temperature has been investigated by an in-depth analysis of published extended X-ray absorption fine structure (EXAFS) spectroscopy and solution chemistry data. In particular, the 3.5–5 Å mid-range atomic environment of Co has been determined with unprecedented precision by combining ad initio FEFF7.02 calculations and results obtained by polarized EXAFS on the mid-distance structure of sheet silicate minerals. The local atomic environment around sorbed Co atoms is identical to that of Co in trioctahedral clays and substantially different from that in the cobalt hydroxide Co(OH)_2(s). Neoformation of a trioctahedral clay is consistent with calculated thermodynamic solubilities, which indicate that 2:1 and 1:1 Co-rich hydrous silicates, similar to kerolite and chrysotile, are less soluble than Co(OH)_2(s). Consequently, precipitation of Co-rich clay is favored over that of Co(OH)_2(s) at pH values below 9 and for a dissolved Si concentration equal to quartz solubility. New experimental data show that dissolved Si concentrations can approach, and even exceed, that of quartz solubility during the short times of sorption experiments. Based on the available data, it is not possible to conclude unequivocally if the Co layer silicate grew epitaxially on the quartz surface, topotactically in a surface amorphous layer, or independently of the quartz framework structure. The structural and chemical interpretation is supported by recent published studies in which sorption of a hydrolyzable cation leads to the neoformation of a mixed layer phase formed from the sorbate species and the sorbent metal. This surface-induced precipitation mechanism is a general phenomenon that may account for the formation of secondary clays as coatings on silicates.