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In this study the replication process was applied to produce porous glass ceramic foams. Polyurethane (PU) sponges were impregnated by immersion in aqueous slurry of a parent glass (mean particle size around 3 mm) from the system Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 and submitted to heat treatment. From TGA and IR analyses, two main paths of thermal decomposition of PU sponges were observed at 312 and 393uC, which were associated with the decomposition products CO 2 , CO, NH 3 and isocyanide. According to linear thermal shrinkage and DTA measurements, sintering starts at around 570uC and is completed below 700uC, when crystallisation takes place. The main crystalline phases identified by XRD analysis were zirconium silicate, lithium metasilicate and b-spodumene. The morphology and properties of the glass ceramic foams obtained from PU sponges were quite similar for all samples tested. From XCT measurements, a mean cell diameter of around 260 mm and mean strut thickness of 185 mm were calculated, corresponding to a porosity of 75-78%. Compressive strength values under 500 kPa and permeability coefficient in air of about 1000 Darcy were also measured for the samples tested. LZSA glass ceramic foams can be a very interesting alternative to ceramic gas filters, owing to low temperature processing, and to superior properties such as corrosion and thermal shock resistance.

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A B S T R A C TTime-resolved spectroscopy of the nova-like variable UU Aquarii is analysed with eclipse mapping techniques to produce spatially resolved spectra of its accretion disc and gas stream as a function of distance from disc centre in the range 3600±6900 A Ê . The spatially resolved spectra show that the continuum emission becomes progressively fainter and redder for increasing disc radius ± reflecting the radial temperature gradient ± and reveal that the H i and He i lines appear as deep, narrow absorption features in the inner disc regions, transitioning to emission with P Cyg profiles for intermediate and large disc radii. The spectrum of the uneclipsed component has strong H i and He i emission lines plus a Balmer jump in emission, and is explained as optically thin emission from a vertically extended disc chromosphere 1 wind. Most of the line emission probably arises from the wind. The spatially resolved spectra also suggest the existence of gas stream`disc-skimming' overflow in UU Aqr, which can be seen down to R . 0X2R L1 X The comparison of our eclipse maps with those of Baptista, Steiner & Horne suggests that the asymmetric structure in the outer disc previously identified as the bright-spot may be the signature of an elliptical disc similar to those possibly present in SU UMa stars during superoutbursts.

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