Metallic nanoparticles with virucidal properties dispersed in a polymeric matrix have gained prominence in the scientific community as a rapid and effective alternative that employs the additive manufacturing (AM) or 3D printing method. This study aims to produce filaments for 3D printing using polymer nanocomposites based on polylactic acid (PLA) and copper nanoparticles (CuNPs) in different proportions. The virucidal activity of various proportions of nanoparticles in PLA was investigated. The composites were produced following a mixture design (DOE) with concentrations ranging from 1% to 2% copper nanoparticles, which were blended with PLA using a single-screw extruder. The samples were characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), tensile strength testing, and fracture analysis using scanning electron microscopy (SEM). A thermal analysis of the composites indicated that the CuNPs contributed to an increase in the degradation temperature and crystallization of the PLA. Sample S7 (1.25% of CuNPs) exhibited a 4% increase in the degradation temperature compared to pure PLA. The best tensile strength results were observed in sample S7 (1.25% of CuNPs), 30% more than sample S3 (1.33% of CuNPs) due to good material cohesion, as evidenced by microscopy analyses. Regarding virucidal analyses, most composites demonstrated virus inhibition activity.

Buriti Fibers extracted from the leafstalk of palm tree, Mauritia flexuosa, native to the Amazon region, have been investigated as a reinforcement of polymer matrix composites. Recently, the fabric made from buriti fibers was also studied as a possible reinforcement of epoxy composites. In particular, the preliminary results of a 10 vol% buriti fabric epoxy composite in a multilayered armor system (MAS) displayed a satisfactory backface signature (BFS) but the composite target was not able to preserve its integrity after the ballistic impact. This motivated the present work, in which we carry out a complete statistical investigation of the ballistic performance of 10, 20, and 30 vol% buriti fabric epoxy composites as a MAS second layer against 7.62 mm rifle ammunition. BFS, associated with the depth of penetration in a clay witness simulating a human body, disclosed values of 18.9 to 25 mm, statistically similar and well below the lethal value of 44 mm specified by the international standard. Absorbed energy in stand-alone ballistic tests of 163–190 J for armor perforation were also found to be statistically higher than 58 ± 29 J obtained for the conventionally applied synthetic aramid fabric. The 30 vol% buriti fabric composites maintained the integrity of the MAS second layer, as required for use in body armor. Failure mechanisms found for the 10 vol% and 20 vol% buriti fabric composites by macro analysis and scanning electron microscopy confirmed the importance of a higher amount such as 30 vol% in order to achieve effective ballistic protection.

O estudo examina a qualidade do pavimento da Avenida Nações Unidas em Parintins, Amazonas, e sua influência na mobilidade urbana e segurança dos usuários. Essa análise está integrada à proposta de implementação de uma estrutura cicloviária, incluindo ciclovia e paraciclos. O objetivo principal é avaliar os impactos da qualidade do pavimento e propor melhorias que otimizem a mobilidade na Avenida Nações Unidas, um trecho de grande relevância para o tráfego local. A pesquisa inclui a análise detalhada das patologias presentes no pavimento, como buracos, trincas e ondulações, e identifica suas causas e consequências para o trânsito e a segurança dos usuários. A metodologia combinou levantamentos quantitativos e qualitativos, baseando-se em dados coletados por meio de questionários com usuários da via, inspeções visuais e aplicação de normas técnicas. Como proposta, o estudo sugere a implementação de infraestrutura de mobilidade urbana, incluindo ciclovias, calçadas acessíveis e a instalação de paraciclos seguindo modelos sustentáveis, como o aplicado em Fortaleza. Os resultados evidenciam a necessidade de intervenções imediatas para garantir maior conforto, segurança e eficiência no deslocamento, além de destacar a importância da manutenção periódica e do planejamento integrado para atender às demandas da população.