Creep Response of Rotating Composite Discs having Exponential Hyperbolic Linear and Constant Thickness Profiles

The study compares the steady state creep response of rotating Al-SiC discs having constant, linear, hyperbolic and exponential thickness with different thickness profiles. All the discs are assumed to have equal volume with the same average thickness. The creep behaviour of the disc material is described by threshold stress based law while the yielding is assumed to follow Tresca criterion. The variable thickness disc is observed to have superior creep response, expressed in terms of stresses and strain rates, to a constant thickness disc. Amongst variable thickness discs, the creep response is observed to be superior for linear thickness disc, when the inner thickness of all the discs is kept the same. However, for the same outer thickness, the disc having hyperbolic thickness profile exhibits the best creep response

Optimized reduction of graphite oxide for highly exfoliated silver nanoparticles anchored graphene sheets for dye sensitized solar cell applications

In the present work, we have synthesized graphene sheets by optimizing reduction of graphite oxide (GO) by hydrazine hydrate (N2H4 center dot xH(2)O) reducing agent and anchored them with silver nanoparticles (Ag NPs). Morphological and spectroscopic studies confirmed the formation of highly exfoliated graphene sheets separated by Ag NPs with improved C/O ratio. The highly electrocatalytic and exfoliated network of graphene sheets/Ag nanocoatings uniformly adhered to FTO substrate has been utilized as platinum (Pt) free counter electrode (CE) in dye sensitized solar cells (DSSC). Fabricated DSSC with only 2.7 mu m thick TiO2 photoanode exhibited photo conversion efficiency (eta = 3.44%) and short circuit current density (J(sc) = 7.03 mA cm(-2)) comparable to DSSC containing Pt-CE without any loss of open circuit voltage (V-oc = 0.71 V) and fill factor (FF = 0.68)

Optimization of Ni2+ /Ni3+ ratio in reduced graphene oxide/nickel oxide nanohybrids for platinum free dye sensitized solar cells

A strategy has been explored to design a novel network of reduced graphene oxide (rGO)/nickel oxide (NiO) nanohybrids with optimized Ni2+/Ni3+ ratio for the fabrication of compact, flexible, and large area Pt-free dye sensitized solar cells (DSSCs). The rGO/NiO nanohybrids were synthesized by a hydrothermal method and characterized by field emission scanning electron microscopy, Brunauer-Emmett-Teller analysis, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. These studies demonstrate that the rGO/NiO nanohybrids with Ni2+ rich species show high catalytic activity toward the I/I-3(-) redox reaction. This led to the fabrication of improved DSSCs with power conversion efficiency as high as 3.69% with these nanohybrids as counter electrodes in comparison with DSSC devices containing counter electrodes based on rGO (1.71%) and NiO (0.75%)