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El neuroblastoma olfatorio es una neoplasia neuroectodérmica maligna rara que afecta a la bóveda nasal y que tiende a invadir las estructuras vecinas, entre estas a la cavidad intracraneal. Su [...]

The present study shows the experimental results about the physical properties and microstructural changes of Portland cement with y and a alumina nanoparticles. All alumina samples were synthesized from an industrial byproduct. Cement matrix was additivated with nanoalumina at different quantities (from 0.5% up to 1% by weight of cement). Porosimetry and gas permeability tests on the hardened cementitious systems were performed. Results showed a 40% decrease in permeability for y-Al2O3 system. The surface analysis of the y-Al2O3-based cementitious specimens was carried out, resulting in a substantial decreasing of their surface area and pore volume in comparison with the reference material. Additionally, a-Al2O3-based cement systems showed less proportion of amorphous CSH gels and portlandite crystals were predominant. In contrast, y-Al2O3 -based composite materials exhibit well defined etringite crystals (needle-like structures), further remarkable changes in the CSH gel morphology, impacting on the macroscopic mechanical properties. [ABSTRACT FROM AUTHOR]