Alvaro Meneguzzi

This work aims to present the activities carried out and the results obtained by the team from the Universidade Federal do Rio Grande do Sul (UFRGS), which volunteered in Parecis - RO during the Operação Sentinelas Avançadas of the Projeto Rondon, in July 2023. The team was responsible for activities in group "B", covering the areas of Communication, Environment, Technology and Production, and Labor, which were directed to all residents of the municipality. These actions involved conducting practical workshops and cultural activities aimed at children, youth, adults, the elderly, public servants, farmers, and indigenous people. The activities were conducted in collective and public spaces, such as schools and community centers. The results obtained highlight the importance of the Projeto Rondon as a public policy aimed at promoting interaction between Brazilian university students and the communities served by the project. This enables the dissemination of scientific knowledge generated in Higher Education Institutions and the exchange of knowledge between local inhabitants and students. It is concluded that the participation of the Universidade Federal do Rio Grande do Sul in the Operação Sentinelas Avançadas was fundamental for the human and professional development of its involved students. A experiência multidisciplinar e coletiva do Projeto Rondon no município de Parecis/RO é fruto da participação voluntária da equipe da Universidade Federal do Rio Grande do Sul (UFRGS) na Operação Sentinelas Avançadas, realizada em julho de 2023 no estado de Rondônia. As atividades ocorreram em locais públicos, como escolas e centros comunitários, com o objetivo de melhorar as condições de vida das pessoas envolvidas por meio de oficinas teórico-práticas sobre diversos temas, incluindo tratamento e preservação de água, boas práticas agrícolas e gerenciamento de resíduos domésticos. Os resultados obtidos destacam a importância do Projeto Rondon como uma ação pública que promove a interação entre estudantes universitários e as comunidades atendidas pelo projeto. Por fim, conclui-se que, ao atingir diretamente 1.290 pessoas com 24 atividades e uma avaliação média de 9,79 pontos, a participação da UFRGS na Operação Sentinelas Avançadas foi exitosa ao atingir seu objetivo de promover a extensão universitária. Palavras-chave: Projeto Rondon; Voluntariado universitário; Desenvolvimento local; Extensão universitária.

In this work, the use of ZrO₂ nanocoating in aluminum substrates, generated by controlled electrochemical chronoamperometry in hexafluorozirconic acid solutions (H₂ZrF₆·5H₂O), resulted in a lower porous films than that obtained by chemical conversion coating. After the application of an epoxy coating, long-term cyclic immersion corrosion tests and scratch tests proved the superior protection of the dual system and the coating lifespan, thanks to the enhanced adhesion of ZrO₂ intermediate layer and the organic coating. As zirconium-based electrolytes are considered more friendly bath if compared to that of other conversion coating processes, like chromating, phosphating or anodizing processes, the study opens new insights to the protection of structural metals in sectors such as automotive, naval and aerospace industries. The main advantages are the employment of lightweight intermediate pre-treatment (nanoscale), compared to conventional ones (microscale), and reduction of waste slurry (electrolyte bath free of additives).

Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO₂ film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO₂ films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

The current standards for evaluating corrosion during salt spray tests rely on the visual analysis of the specimens, and this may be a limitation when higher resolution quantitative outputs are desired. In this work, computational image analysis was used to measure the area affected by corrosion during salt spray tests with aluminum alloy, copper, carbon steel and galvanized steel plates. The software ImageJ was used to select and measure the corroded areas differentiating the corrosion products from the metals uncorroded surfaces according to their different colors. With ten measurements for each selected exposure time, a 95 % confidence interval was calculated for each material and time of exposure, giving an indication of the precision of the estimated corroded area. These data were compared with a visual inspection carried out by an experienced technician. The results indicate that computational image analysis may be a powerful tool to obtain higher resolution in the results interpretation in comparison with the standard visual analysis.

This paper presents the production of an epoxy paint associated with a determined concentration of PAni emeraldine base binder, in order to increase dispersion of PAni polymer chains in the paint allow physical contact between PAni chains, the electrolytic medium, and the metal of interest. The coating called Intelligent Epoxy Paint (IEP) seeks to potentialize the electrolytic capacity of PAni to produce passivation, differentiated research which uses PAni in oxidized and conductive form as paint pigment that needs high PAni concentrations. The physicochemical characterization and morphological presented results that indicate the preservation of the desirable properties of PAni in order to make the passivation process possible. The electrochemical tests showed the passivation and/or maintenance of the passivation of the metal of interest, without the need to apply an external current.

The focus of this study is to evaluate the efficiency of oxidation processes in the treatment of a solution containing Rhodamine-B (RhB) used in various industrial applications. The advanced oxidation processes of electrooxidation (EO) and photoelectrooxidation (PEO) were used. At the same time, direct photolysis (DP) was also applied. Total organic carbon (TOC) reduction and color removal were evaluated. There was an efficient color removal when DP was performed, and the color removal efficiency was the highest when NaCl was used as supporting electrolyte for PEO and EO. However, the TOC reduction was low, indicating that the degradation of the color does not correspond to the pollutant mineralization.