Soft body impact on composites:Delamination experiments and advanced numerical modelling

Cohesive interface elements have become commonly used for modelling composites delamination. However, a limitation of this technique is the fine mesh size required. Here, a novel cohesive element formulation is proposed and demonstrated for modelling the numerical cohesive zone with equal fidelity but fewer elements in comparison to a linear cohesive element formulation. The newly proposed formulation has additional degrees of freedom in the form of nodal rotations which when combined with the use of multiple integration points per cohesive element, allows for delamination propagation to be modelled with increased stability. This element formulation is introduced with an adaptive modelling method, termed Adaptive Mesh Segmentation (AMS). To demonstrate its effectiveness under impact loading the new model is applied to a soft body beam bending test. This test, containing a delamination pre-crack, uses inertial constraints and results in a dynamic stress state when impacted by a gelatin cylinder

Silver nanoparticles, synthesized using Hyptis suaveolens (L) poit and their antifungal activity against Candida spp.

Silver nanoparticles (AgNPs), due to their interesting properties and many potential applications have attracted enormous interests in recent years. An attempt has been made in this present study to synthesize AgNPs through biological reduction of silver nitrate, with leaf extract of Hyptis suaveolens (L) Poit serving as a reducing agent. AgNPs formed were characterized with spectral (UV-Vis, XRD, FTIR) and electron microscopic investigations. Dispersed spherical nanosilver particles in the range of 2 nm–85 nm were observed through microscopic analysis and the crystalline nature was evidenced through XRD analyses. Anticandidal activity of biosynthesised AgNPs was evaluated against two Candida albicans strains. The minimum inhibitory concentration (MIC) values for AgNPs against the two clinical strains were 0.27±0.03 μg/ml and 0.97±0.13 μg/ml. AgNPs were found to be more effective than the amphotericin-B used as control against the strains of the test pathogens. Scanning electron microscopic (SEM) analyses of the Candida cells treated with AgNPs shows change in the surface morphology, suggesting cell wall disruption to be a potential mode of anticandidal activity. Based on our observations, AgNPs synthesized with leaf extract of Hyptis suaveolens could be potentially used in combating candidal infections.Universidade de Vigo/CISU