No abstract available

[en] Due to an oversight, the Surname of Haya Alhummiany was incorrectly spelled in the published online version. The correct surname is “Alhummiany”, instead of “Alhumminay”. The correct spelling is also shown above.

[en] Organized meso porous materials represent a class of molecular sieves because of its high potential for commercial applications in adsorption and catalysis. In this study, organized meso porous alumina was synthesized by the sol-gel method using various organic templates, i.e. cationic, neutral and anionic surfactants. Surface porosity of the synthesized alumina obtained exhibit materials in the meso pore ranges. The morphology of the samples consists of wormhole-like meso structure in the nano-region (20 - 70 nm). Sample with cetyl trimethylammonium bromide as cationic templates has the narrowest pore distribution centred at 8 nm as compared to samples synthesized with Triton X-114 (neutral) and stearic acid (anionic). All samples showed only Lewis acidity. Acidity and meso porous character present in these meso porous alumina samples showed that this material has potential as catalyst support and also used in Lewis acid catalyzed reactions. Study showed that the cationic surfactant is a better template to obtain uniform meso porous alumina that might be due to the weak interaction between the template and the surface of the alumina. (author)

[en] Published in summary form only

[en] The plan of breakdowns elimination is presented. The possible breakdowns and their elimination were studied.

No abstract available

[en] The phenomenon of electrostatic charge in ceramic powders takes place when the particle surfaces enter in contact between them or with the containers. The accumulation of electrostatic charge is of relevance in ceramic powders in view of their insulating character and the risk of explosions during the material handling. In this work the main factors that affect the appearance of intrinsic charge and tribo-charge in ceramic powder have been studied. In ceramic powders of alumina it has been verified that the smallest particle sizes present an increase of the electrostatic charge of negative polarity. A correlation has been observed between the nature of the OH -surface groups and the electrostatic charge. The intrinsic charge and the tribocharge in ceramic powders can be diminished by compensating the surface groups that support the charge. The dry dispersion of nanoparticles on microparticles allows surface charge compensation with a noticeable modification of the powder agglomeration. (Author) 19 refs.

[en] Highlights: • Eu and Dy doped strontium aluminates fabricated using different methods with similar 3D spectra. • The experimental study of both Switch ON and Switch OFF spectral and time responses. • Time rise and time decay responses can be entirely or partially fit by power law and logarithmic functions. • All samples exhibit spectrally dependent time responses. • Eu, Dy doped samples exhibit stronger spectral dependences for both rise and fall responses. In this paper we have studied the rise and decay time responses of Eu and Dy doped strontium aluminates prepared by different methods. The spectrum was characterized by 3D excitation emission matrices (EEM). The normalized rise and decay responses of the total power and at two wavelengths on either side of the spectral maximum exhibit individual behavior. We show that the individual switch on and switch off time responses can be approximated by power law and logarithmic dependencies. The relation between spectral and time responses and the sample contents and technology of fabrication is commented.

[en] Recent results have strongly suggested that the ballistic-resistance of different comminuted ceramics is similar, independent of the original strength of the material. In particular, experimental work focused on the ballistic response of such materials has suggested that ballistic response is largely controlled by shattered material morphology. Consequently, it has been postulated that control of the nature of ceramic fragmentation should provide a potential route to optimise post-impact ballistic resistance. In particular, such an approach would open up a route to control in multi-hit capabilities. Here, ballistic tests into pre-formed 'fragmented-ceramic' analogues assembled from compacted alumina powders with two differing morphologies were conducted. Strong hints of a morphology-based contribution to ballistic resistance were apparent, although there was insufficient fidelity in the experimental data set to categorically identify the nature of this contribution.

No abstract available