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Biomass has attracted considerable attention as energy, economic, and environmental asset, as result of its abundance and range of properties. The use of mesoporous catalysts during fast pyrolysis has been a highly important route to improve efficiency as well adding value to biomass. The addition of titanium to molecular sieves increases the efficiency of the pyrolysis reaction by improving production and selectivity of products of interest. This study aims at analyzing the catalytic pyrolysis products of elephant grass using titanium catalysts prepared at different Si/Ti molar ratios, i.e., 25 and 50. The material was supported on MCM-41 for the catalytic pyrolysis of biomass. The biomass pyrolysis reactions were performed in a micropyrolyzer coupled to a GC/MS analyzer. The Ti-MCM-41 samples were characterized by XRD, BET-specific area, and UV-visible. The distribution of pyrolysis products depended on process parameters such as temperature and catalyst type. The highest yield for hydrocarbon production, such as styrene, benzene, methylbenzene, and naphthalene, was observed at 600 °C using Si/Ti equal to 50.

The aim of this study was to evaluate the evolution of mechanical properties and chemical variation across veneering dental porcelain fused to different titanium-based substrates. Test samples were synthesized by fusing dental feldspar-based porcelain onto commercially pure titanium grade II or Ti6Al4V alloy. Samples were cross-sectioned at angles of 10 and 90° to the interface plane. Afterwards, nanoindentation tests and Scanning Electron Microscopy (SEM) imaging coupled to an Energy Dispersive Spectroscopy (EDS) system were carried out across interfaces extending from the metal towards the porcelain area. Elemental diffusion profiles across the porcelain-to-metal interfaces were also obtained by EDS analysis. The mismatch in mechanical properties found in porcelain-to-Ti6Al4V interfaces was lower than that of porcelain-to-CP titanium. Cracking was noticed at low-thickness veneering dental porcelain regions after the nanoindentation tests of samples cross-sectioned at low angles to the interface plane. A wide reaction zone between titanium and porcelain as well as higher incidence of defects was noticed at the porcelain-to-CP titanium interfaces. This study confirmed Ti6Al4V as an improved alternative to CP-titanium as it showed to establish a better interface with the veneering dental porcelain considering the slight chemical interaction and the lower mechanical properties mismatch. The elastic modulus of porcelain-to-Ti6Al4V samples showed to be less sensitive to porcelain thickness variations., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Abstract: The purpose of this study was to analyze the mechanical strength and microstructure of dental metal–ceramic interfaces immersed in acidic artificial saliva after mechanical metallization of a NiCr-based substrate. Commercial NiCrMo alloy and dental porcelain were characterized before the production of metal–ceramic specimens. Therefore, a group of metallic surfaces was mechanically metallized with Ti. After that, metal–ceramic interfaces were produced and immersed in an electrochemical cell containing artificial saliva. In order to accelerate the corrosion of the interfaces, a potential of 0.75V was applied on the metallic substrate for 30min. 3-point bending tests of the metal–ceramic systems were carried out according to the ISO-9693 standard before and after immersion tests. The metallic surfaces as well as the metal–ceramic interfaces were analyzed by SEM–EDS. There was a decrease of the mechanical strength of conventional metal–ceramic interface after immersion. However, the mechanical strength of the samples with metallized interfaces remained unaltered after immersion in artificial saliva. [Copyright &y& Elsevier]