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One key question regarding current climate models is whether the projection of climate extremes converges to a realistic representation as the spatial and temporal resolutions of the model are increased. Ideally the model extreme statistics should approach a fixed distribution once the resolutions are commensurate with the characteristic length and time scales of the processes governing the formation of the extreme phenomena of interest. In this study, a series of AGCM runs with idealized 'aquaplanet-steady-state' boundary conditions have been performed with the Community Atmosphere Model CAM3 to investigate the effect of horizontal resolution on climate extreme simulations. The use of the aquaplanet framework highlights the roles of model physics and dynamics and removes any apparent convergence in extreme statistics due to better resolution of surface boundary conditions and other external inputs. Assessed at a same large spatial scale, the results show that the horizontal resolution and time step have strong effects on the simulations of precipitation extremes. The horizontal resolution has a much stronger impact on precipitation extremes than on mean precipitation. Updrafts are strongly correlated with extreme precipitation at tropics at all the resolutions, while positive low-tropospheric temperature anomalies are associated with extreme precipitation at mid-latitudes. © 2011 The Authors Tellus A © 2011 John Wiley & Sons A/S.

In this work controlled release devices for transdermal administration of metoprolol were developed. Poly(vinyl alcohol) and poly(vinyl pyrrolidone) were used for producing membranes by solvent-casting technique. The release kinetic of the drug from the membranes was evaluated by ex-vivo experimental studies. All the prepared membranes exhibited a linear release profile in the investigated time. The enhancer Tween 80 was added into the polymeric matrices for improving their performance. Different mathematical models were used for fitting the experimental release data. The model that well described the release mechanism was the zero order, indicating a constant drug release in the time. [ABSTRACT FROM AUTHOR]

In this work was studied the effect of different zeolite topologies on the release of ibuprofen from mixed matrix membranes (MMMs). The main parameters investigated were: zeolite concentration, its hydrophilic/hydrophobic character, and drug loading. About the different investigated systems, the PDMS NaX (I) membrane seems to be the most promising for its application as transdermal device. The release data were fitted with different mathematical models (zero order, first order, Higuchi, Bhaskar, and Korsemeyer-Peppas) to give a possible explanation of the release mechanism of the drug from MMMs. The release data of the drug from pure PDMS membranes (PDMS IBU) were fitted by the Higuchi model ( R2 pari a 0.97). In the case of MMMs, the correlation coefficients are very far from the unit value except for the PDMS NaX (I) system that obeys to the Korsmeyer-Peppas (0.98) and Bashkar (0.99) models. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Abstract: CO selective oxidation (Selox) for the purification of hydrogen-rich streams was studied in membrane reactors (MRs) using Pt-loaded catalytic membranes. The catalytic membranes were prepared by the ion-exchange of FAU (Na-Y) zeolitic membranes that were synthesized on tubular α-Al2O3 supports by a secondary growth method. The catalytic MR tests were performed analysing the CO conversion, O2 selectivity and yield of the desired reaction. Different feed compositions (CO, O2, H2 and N2 content and O2/CO ratio), temperatures and pressures were considered with space-time values in the range 0.27–1.2mgPt min/cm3(STP). The CO content in preliminary tests was 10%, 1% in the other experiments. A simulated reformate shifted gas mixture (H2 =60%) was also used. A comparison with other literature data for MRs utilizing different membrane types and packed bed traditional reactors with Pt-based catalysts is also provided. The identified ranges of operating conditions (temperature, pressure, feed molar O2/CO ratio and feed concentration) suggest a profitable use of the catalytic MR (Pt-Y zeolite membranes) for CO Selox after the low-temperature water gas shift unit of a fuel processor converting hydrocarbons into hydrogen-rich gas, operating at similar temperature conditions. [Copyright &y& Elsevier]