Carbon fiber non-crimp multi-axial reinforcement and epoxy mono-component system composite: Fatigue behavior

AbstractFiber reinforced polymer composites have been widely applied in the aeronautical field. However, composite processing, which uses unlocked molds, should be avoided in view of the tight requirements and also due to possible environmental contamination. To produce high performance structural frames meeting aeronautical reproducibility and low cost criteria, the Brazilian industry has shown interest to investigate the resin transfer molding process (RTM) considering being a closed-mold pressure injection system which allows faster gel and cure times. Due to the fibrous composite anisotropic and non homogeneity characteristics, the fatigue behavior is a complex phenomenon quite different from to metals materials crucial to be investigated considering the aeronautical application. Fatigue sub-scale specimens of intermediate modulus carbon fiber non-crimp multi-axial reinforcement and epoxy mono-component system composite were produced according to the ASTM 3039 D. Axial fatigue tests were carried out according to ASTM D 3479. A sinusoidal load of 10 Hz frequency and load ratio R=0.1. It was observed a high fatigue interval obtained for NCF/RTM6 composites. Weibull statistical analysis was applied to describe the failure probability of materials under cyclic loads and fractures pattern was observed by scanning electron microscopy

Rhizobium Presence and Functions in Microbiomes of Non-leguminous Plants

The genus Rhizobium is well known in the context of its interaction with leguminous plants. The symbiosis Rhizobium-legume constitutes a significant source of ammonia in the biosphere. Rhizobium species have been studied and applied as biofertilizers for decades in legumes and nonlegumes, due to the potential as N-fixer and plant growth promoter. Since its discovery, conventional culture-dependent techniques were used to isolate Rhizobium members from their natural niche, the nodule, and their identification was routinely performed via 16S rRNA gene and different housekeeping genes. Biotechnological advances based on the use of omics-based technologies showed that species belonging to the genus Rhizobium are keystone taxa in several diverse environments, such as forests, agricultural land, Arctic, and Antarctic ecosystems, contaminated soils and plant-associated microbiota. In this chapter, we will summarize the advances in the study of the Rhizobium genus, from culturomics strategies to modern omics methodologies, mostly based on next-generation sequencing approaches. These cutting-edge molecular approaches are fundamental in the study of the behavior of Rhizobium species in their interaction with Non-leguminous plants, supporting their potential as an ecological alternative to chemical fertilizers in the battle against Climatic Change