Investigation on optical switching behaviour of regenerated and non-regenerated silk by nanosecond Z-scan technique

The nonlinear optical behaviour of silk, a natural fibre, is investigated in this study. We have considered silk in the cocoon, fibre and film forms of bivoltine and multivoltine breeds. The nonlinear absorption and optical limiting studies were performed using the open aperture Z-scan technique at 1064nm. Interestingly, silk in cocoon and fibre form possess saturable absorption (SA), whereas silk in the film form exhibits reverse saturable absorption (RSA). This shift is attributed to the removal of sericin during the regeneration of silk into a film. Further, silk films exhibit optical limiting behaviour, whose limiting thresholds are in the order of 1012 W/cm2. Functional data analysis (FDA), a statistical approach, is employed to draw correlations amongst physical parameters. FDA offers good insight into the dependencies between silk varieties and their optical parameters. This helps in identifying the sample possessing the best properties.

Thermal Degradation and Mechanical Characteristics of Sugarcane Bagasse Reinforced Biodegradable Potato Starch Composites

Global pollution due to the overwhelming usage of non-biodegradable plastics is getting severe nowadays. Hence, the aim of this paper is to develop an environmentally friendly composite material from potato starch and sugarcane bagasse. The composites were prepared by hot pressing at 145? for 60 min. The composites were characterize for their mechanical and thermal properties. In terms of thermal properties, thermogravimetric analysis shows that incorporation of sugarcane fiber has improved the thermal stability of the composites. Meanwhile, incorporation of sugarcane fibre form 0 to 15 wt.% has significantly improved the tensile and flexural properties of the composites. Scanning electron micrograph of the tensile fracture showed the fibre fracture and fibre “pull-out” from the composite. Overall, the biodegradable composites has shown improved functional characteristic than the origin material. This finding shows that this Sugarcane/Potato starch composites are potential alternative material for biodegradable product i. e biodegradable plastic packaging.

Alteration by Cerium Element on Primary and Eutectic Mg2Si Phases in Al-20%Mg2Si In Situ Composite

Owing to its beneficial material properties, Al-Mg2Si in-situ composite has recently received wide attention and application in the manufacture of automotive and aerospace components. Melt treatment of the in-situ composite with the addition of Ce has resulted in a change in the primary and eutectic Mg2Si phases to refined morphology, which would be expected to improve the mechanical properties of the composite. Characteristic parameters of Mg2Si particles have been investigated via thermal and microstructural analysis. This has revealed that the addition of 0.8wt.% Ce produced optimum refinement effects on Mg2SiP because the coarse structure has been changed to a polygonal shape and reduced in size. Similarly, the flake-like morphology of Mg2SiE has been transformed into a rod-like or fibre form in addition to reduction of the eutectic cell area. The result also showed an increase in nucleation temperature TN of Mg2SiP while depressed for Mg2SiE, which also corresponds to the refinement morphology effect.

Influence of Wire Reinforcement on the Forming Behaviour of Adhesive Bonded Steel Sheets

A method for modifying the properties of adhesives is by the addition of metallic wire strand in fibre form to improve the thermal conductivity for use in electrical applications. Clearly any advantage gained as far as thermal conductivity is concerned should not be counteracted by deficiencies in mechanical properties. In this work, the influence of copper wire reinforcements on the tensile behaviour of adhesive bonded steel sheets will be presented. The adhesive used is a two-part epoxy resin with a mix ratio of 1:1 parts by weight of resin to hardener. Wire strands used are copper wires having a diameter of 0.3 mm. The base materials are made of Stainless Steel. The stress-strain behaviour, and limit strain are evaluated through tensile tests and in-plane plane-strain (IPPS) formability tests. It is found that the ductility and limit strain of adhesive bonded sheets with wire reinforcement are better than that of the case without reinforcement. The ductility and limit strain of wire reinforced adhesive bonded sheets increases till three wires in the case of tensile tests, and four wires in the case of IPPS formability tests, after which it decreases.