CNTs tuning and vertical alignment in anodic aluminium oxide membrane

Anodic aluminium oxide （AAOM） membranes were used for template growth of carbon nanotubes （CNT） inside their pores by chemical vapour deposition （CVD） of different hydrocarbons, in the absence of transition metal catalyst. A composite material, containing one nanotube for each channel, having the same length as the membrane thickness and the external diameter close to the diameter of the membrane holes, was obtained. Yield, selectivity, and quality of CNTs in terms of diameter （up to very thin CNT）, carbon order, length, arrangement （i.e. number of tubes for each channel）, purity, that are critical requisites for several applications were optimised by investigating the effect of changing the hydrocarbon feedstock gas, also in the presence of hydrogen. The samples produced using methane as a feedstock have a well ordered structure. The role of the alumina channels surface during the CNT growth has been investigated and its catalytic activity has been proved for the first time.

Thermal Radiation Modelling in Tunnel Fires

Modelling based on Computational Fluid Dynamics(CFD)is by now effectively used in fire research and hazard analysis.Depending on the scenario,radiative heat transfer can play a very important role in enclosure combustion events such as tunnel fires.In this work,the importance of radiation and the effect of the use of different approaches to account for it were assessed.Firstly,small-scale tunnel fire simulations were performed and the results compared with experimental data,then realistic full-scale scenarios were simulated.The results show up the capability of CFD modelling to reproduce with good approximation tunnel fires.Radiation proved to be noteworthy mainly when the scale of the fire is relatively large.Among the various approaches employed to simulate radiation,the use of the Discrete Transfer model gave the most accurate results,mainly when the absorption-emission characteristics of the combustion products were taken into account.Finally,the suitability of the use of CFD in quantitative Fire Hazard Analysis is discussed.

Visible light driven mineralization of spiramycin over photostructured N-doped TiO2 on up conversion phosphors

A novel visible light-active photocatalyst formulation（NdT/OP） was obtained by supporting N-doped TiO2（NdT） particles on up-conversion luminescent organic phosphors（OP）. The photocatalytic activity of such catalysts was evaluated for the mineralization process of spiramycin in aqueous solution. The effect of NdT loading in the range 15–60 wt.% on bulk and surface characteristics of NdT/OP catalysts was investigated by several chemicophysical characterization techniques. The photocatalytic performance of NdT/OP catalysts in the removal of spyramicin from aqueous solution was assessed through photocatalytic tests under visible light irradiation. Total organic carbon（TOC） of aqueous solution,and CO and CO2 gas concentrations evolved during the photodegradation were analyzed. A dramatic enhancement of photocatalytic activity of the photostructured visible active NdT/OP catalysts,compared to NdT catalyst,was observed. Only CO2 was detected in gas-phase during visible light irradiation,proving that the photocatalytic process is effective in the mineralization of spiramycin,reaching very high values of TOC removal. The photocatalyst NdT/OP at 30 wt.% of NdT loading showed the highest photocatalytic activity（58%of TOC removed after 180 min irradiation against only 31% removal after 300 min of irradiation of NdT）. We attribute this enhanced activity to the high effectiveness in the utilization of visible light through improved light harvesting and exploiting. OP particles act as ＂photoactive support＂,able to be excited by the external visible light irradiation,and reissue luminescence of wavelength suitable to promote NdT photomineralization activity.