Large-scale numerical modelling of CO2 injection and containment phases for an Italian near-coast reservoir using PFLOTRAN

A potential CO2 storage site located offshore the west coast of Italy, has been modelled using PFLOTRAN assuming an injection rate of 1.5 Mtons/year for 20 years. The model predicts a CO2 footprint characterised by a diameter of about 3.5 km and a maximum pressure build up of 38 bars. The solubility trapping has been quantified, predicting a dissolution in brine of 69% and 79% of the total amount of CO2 injected after 1000 and 2000 years respectively. The residual trapping has also been found to play an important role, with 9% and 6% of the injected CO2 being locked into the hosting matrix pores after 1000 and 2000 years respectively. Considering a worst-case scenario for leakages, where zero critical capillarity pressure has been assumed, minor CO2 leakages through the caprock have been identified, caused by the combined effects of the long-term structural trapping and the large and lasting overpressure caused by the CO2 injection in an ideally closed system. Finally, some preliminary work undertaken as part of an ongoing effort to couple a geochemical model to the multi-phase flow simulations reveals i) small changes in mineral volume fraction and porosity during and after the injection (~5% after 1000 years), and ii) a not negligible self-sealing effect due to precipitation of calcite in the lower layer of the caprock. Further investigations and longer physical time runs are needed to confirm this assumption, but also to gain more confidence on the geochemical model built so far and to estimate the mineral trapping potential for this site. © 2013 The Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of SINTEF Energi AS

Strengths and Weaknesses in the Intellectual Profile of Different Subtypes of Specific Learning Disorder

The present study analyzes whether and how the most common diagnoses within the specific learning disorder (SLD) category are characterized by different intellectual profiles. The issue is relevant to the current debate on the unitary versus decomposable nature of the SLD category and may help define specific interventions. Intellectual profiles were obtained using the Wechsler Intelligence Scale for Children–IV (WISC-IV) on 1,049 children diagnosed with SLD using the ICD-10 codes. Four major subsamples were compared: reading disorder, spelling disorder, disorder of arithmetical skills, and mixed disorder of scholastic skills. The four main WISC-IV indexes (verbal comprehension, perceptual reasoning, working memory, and processing speed) were considered. Results showed that all SLD subgroups share similar weaknesses in working memory and processing speed, but they also showed that the subgroups are characterized by partly different intellectual profiles. These specificities should be considered in the definition of SLD

GPS-based CERN-LNGS time link for Borexino

We describe the design, the equipment, and the calibration of a new GPS based time link between CERN and the Borexino experiment at the Gran Sasso Laboratory in Italy. This system has been installed and operated in Borexino since March 2012, and used for a precise measurement of CNGS muon neutrinos speed in May 2012. The result of the measurement will be reported in a different letter.Comment: 13 pages, 11 figure

Intercomparisons of airborne measurements of aerosol ionic chemical composition during TRACE-P and ACE-Asia

As part of the two field studies, Transport and Chemical Evolution over the Pacific (TRACE-P) and the Asian Aerosol Characterization Experiment (ACE-Asia), the inorganic chemical composition of tropospheric aerosols was measured over the western Pacific from three separate aircraft using various methods. Comparisons are made between the rapid online techniques of the particle into liquid sampler (PILS) for measurement of a suite of fine particle a mist chamber/ion chromatograph (MC/IC) measurement of fine sulfate, and the longer time-integrated filter and micro-orifice impactor (MOI) measurements. Comparisons between identical PILS on two separate aircraft flying in formation showed that they were highly correlated (e.g., sulfate r2 of 0.95), but were systematically different by 10 ± 5% (linear regression slope and 95% confidence bounds), and had generally higher concentrations on the aircraft with a low-turbulence inlet and shorter inlet-to-instrument transmission tubing. Comparisons of PILS and mist chamber measurements of fine sulfate on two different aircraft during formation flying had an r 2 of 0.78 and a relative difference of 39% ± 5%. MOI ionic data integrated to the PILS upper measurement size of 1.3 mm sampling from separate inlets on the same aircraft showed that for sulfate, PILS and MOI were within 14% ± 6% and correlated with an r 2 of 0.87. Most ionic compounds were within ±30%, which is in the range of differences reported between PILS and integrated samplers from ground-based comparisons. In many cases, direct intercomparison between the various instruments is difficult due to differences in upper-size detection limits. However, for this study, the results suggest that the fine particle mass composition measured from aircraft agree to within 30–40%

Investigations into free tropospheric new particle formation in the central Canadian arctic during the winter/spring transition as part of TOPSE

In this paper, we investigate the role of in situ new particle production in the central Canadian sub-Arctic and Arctic as part of the TOPSE experiment. Airborne measurements conducted primarily in the free troposphere were made from 50° to 90°W longitude and 60° to 85°N latitude during the period from February to May 2000. Data pertinent to this paper include 3–4 nm diameter (Dp) particles, ultrafine condensation nuclei (Dp \u3e 3 nm), fine particles (0.2 \u3c Dp \u3c 3 μm), and the possible nucleation precursor, sulfuric acid, and its precursor, sulfur dioxide. For data averaged over this period, most species showed little evidence for a latitudinal trend. Fine aerosol number concentrations, however, showed a slight increase with latitude. The evolution of various species concentrations over the period of the study show that fine particles also had a consistent temporal trend, increasing at all altitudes from February to May, whereas sulfur dioxide at the surface tended to peak in late March. Ultrafine condensation nuclei and 3–4 nm particles showed no temporal trends. Little evidence for in situ new particle production was observed during the study, except for one atypical event where SO2concentrations were 3.5 ppbv, 2 orders of magnitude higher than typical levels. This paper cannot address the question of whether the observed condensation nuclei were produced in situ by a low particle production rate or transported from lower latitudes