-Due to ever more severe environmental regulations regarding SOx, NOx and other pollutants' emissions, there has been an interest in developing new and improved catalysts for hydroprocessing reactions. Mo2C has been reported to display good selectivity and activity for those reactions, especially for HDS. Addition of another metal to the carbide structure may improve catalytic properties. Mo2C with low cobalt addition (2.5 and 5%) was obtained via gas-solid reaction in a fixed bed reactor with CH4 (5%)/H2 atmosphere. XRD and TG/DTA analysis of the precursors were carried out in order to understand its mass loss profile, doping metal presence and phase distributions. CoMoO4 as well as MoO3 were identified after calcining doped precursors at 600 °C/180min. SEM, XRD, XRF, TOC, BET and laser granulometric analysis of the reaction products were also performed. Compositions verified by XRF and theoretical values were compatible. At 700 °C both carbide (Mo2C) and oxide (MoO2) phases are present, as identified in XRD analysis and observed by SEM. At 750 °C only single phase Mo2C was verified by XRD, indicating Co dispersion on the carbide matrix. Morphology at this temperature is compatible with pure Mo2C, though XRF indicates Co presence on the material.

The present paper's objective was to synthesize and characterize both the oxalic niobium precursor (NH 4 ) 3 NbO(C 2 O 4 ) 3 .H 2 O, and the product of its doping with Cu and calcining, CuNb 2 O 6 . In order to obtain the niobium precursor, commercially available niobium oxide (Nb 2 O 5 ) was subject to fusion with potassium bisulfate (KHSO 4 ). Once leached with water, the powder was complexed with oxalic acid and ammonium oxalate. The as produced material was manually mixed with copper nitrate Cu(NO 3 ) 2 .2H 2 O (25% Cu molar) and calcined at 1000°C in a muffle furnace. CuNb 2 O 6 was then obtained. The precursor was characterized by XRD, SEM, FT-IR, XRF, TG/DTG. The calcination product was characterized by XRD, XRF and SEM. Results show that single phase CuNb 2 O 6 could be obtained by this method without Nb 2 O 5 contamination.

Molybdenum oxides are very interesting technologic materials, which present several industrial uses. The addition of a second metal may enhance its catalytic properties as well as change electronic behavior. Several methodologies for adding a second metal can be found in the literature, however, the comparison between them is hardly ever found. Here two processing routes were tested for the synthesis of molybdenum oxide with cobalt addition: solid-state and wet routes. Ammonium molybdate and cobalt nitrate were used as starting materials and cobalt addition was carried out before calcination. Starting materials were characterized by SEM, FTIR, XRF, and XRD. Calcination products were evaluated by SEM, XRF, XRD and UV-vis spectroscopy. Calcined products whose doping was performed via solid-state presented smaller crystal size (~25 nm), larger cobalt retention (deviation, δ ~10%) and slightly smaller band gap in comparison to those doped via the wet route (~40 nm and δ>11%).

The use of niobium containing materials' has gained much attention of the scientific community in the late years due its various applications in diverse fields. NbC is a highly versatile material. Copper addition may alter several of its properties, such as morphology, crystal structure etc. as well as enhance its catalytic behavior. Nanostructured NbC with copper addition synthesis' presented here had the precursor [(NH 4 ) 3 [NbO(C 2 O 4 ) 3 ] x H 2 O] as starting material, which was doped with Cu(NO 3 ) 2 at 5% and 10% (molar) ratios. Doped NbC was obtained via gas solid reaction in fixed bed reactor at lower temperature (980°C) and with shorter reaction time (2h) than traditional methods. Reaction products' were characterized by XRD, crystal sizes were estimated according to HWL method, and SEM, XRF, BET and laser particle size analysis were performed. XRD indicated the formation of NbC and Cu phases with cubic crystal structure of ~20nm. SEM showed slight morphological change upon increasing copper content, indicating a less porous structure, which is consistent with BET data (43.7m2 /g for 5%Cu-NbC and 37m 2 /g for the 10% Cu-NbC). Crystal size calculations showed that increasing dopant content particle sizes were also increased, probably due to the presence of the dopant, in some extent, in the crystal structure.

One of the many different purposes of software architecture descriptions is contributing to an early analysis of the architecture with respect to quality attributes. The critical nature of many software systems calls for formal approaches aiming at precisely verifying if their designed architectures can meet important properties such as consistency, completeness, and correctness. In this context, it is worthwhile investigating the role of architecture descriptions to support the formal verification of software architectures to ensure their quality, as well as how such a process happens and is supported by existing languages and verification tools. To evaluate the research landscape on this subject, we have carried out a systematic mapping study in which we collected and analyzed studies available at the literature on formal verification of architecture descriptions. This work contributes with (i) a structured overview and taxonomy of the current state of the art on this topic and (ii) the elicitation of important issues to be addressed in future research.