Graphene-based nanocomposites possess excellent mechanical, electrical, thermal, optical, and chemical properties. These materials have potential applications in high-performance transistors, biomedical systems, sensors, and solar cells. This paper presents a critical review of the recent developments in graphene-based nanocomposite research, exploring synthesis methods, characterizations, mechanical properties, and thermal properties. Emphasis is placed on characterization techniques and mechanical properties with detailed examples from recent literature. The importance of characterization techniques including Raman spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) for the characterization of graphene flakes and their composites were thoroughly discussed. Finally, the effect of graphene even at very low loadings on the mechanical properties of the composite matrix was extensively reviewed.

Fatigue and mechanical properties of nanostructured and conventional titania (TiO₂) thermal spray coatings Ibrahim, A.; Lima, R. S.; Berndt, C. C; Marple, B. R.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca. Abstract Nanostructured and conventional titania (TiO 2 ) coatings were thermally sprayed using air plasma spray (APS) and high velocity oxy-fuel (HVOF) processes. The fatigue and mechanical properties of these coatings were investigated. A previous study characterized these coatings by scanning electron microscopy (SEM) to investigate the microstructural features and Vickers indentation to determine the hardness and crack propagation resistance. This current complementary SEM work examined fracture surfaces of fatigue-tested samples to assess crack nucleation and to study mechanisms of deformations. The fatigue strength of coatings deposited onto low-carbon steel (AISI 1018) showed that the nanostructured titania coated specimens exhibited significantly higher fatigue strength compared to the conventionally sprayed titania. The straintime curve of AISI 1018 coated with TiO 2 indicated that the strain amplitude of the HVOF-sprayed nanostructured TiO 2 coating was much lower than the corresponding data of APS conventional TiO 2 . SEM analysis of fracture surfaces revealed valuable information regarding the influence of these coatings on the performance of the coated component. This investigation gives new understanding to the nature of fatigue and deformation of the nanostructured and conventional titania (TiO 2 ) coatings.

No abstract

This paper discusses the stresses developed in a thin-walled pressure vessels. Pressure vessels (cylindrical or spherical) are designed to hold gases or liquids at a pressure substantially higher than the ambient pressure. Equations of static equilibrium along with the free body diagrams will be used to determine the normal stresses 1 σ in the circumferential or hoop direction and 2 σ in the longitudinal or axial direction. A case study of internal pressure developed in a soda can was determined by measuring the elastic strains of the surface of the soda can through strain gages attached to the can and connected to Strain indicator Vishay model 3800.

No abstract