Photocatalytic water splitting for hydrogen production

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Anisotropy shift and Raman bandwidth studies in carbonyl containing molecule o-chlorobenzaldehyde: role of repulsive forces

The analysis of Raman anisotropy shift as a function of solvent concentration shows the weakening of pair interaction of the molecules due to the influence of solvent-induced perturbations. The present study deals with the effect of dielectric constant of the medium on the non-coincidence effect (anisotropy shift) and the role of van der Waals' volume on the anisotropic Raman bandwidth. The CO stretching vibration of o-chlorobenzaldehyde (OCBD) molecule was studied in various polar and non-polar solvents namely CCl4, CH3CN, C6H5Cl and CH3C6H5. The data on anisotropic bandwidth are interpreted using the van der Waals' volume within the framework of lineshape theory of Bratos and Tarjus, while the Onsager-Fr?hlich model on non-coincidence effect has been tested. Our study shows that the repulsive potential of the type e-alphaR is playing an important role in the OCBD-solvent interactions. The vanishing of anisotropy shift (non-coincidence effect) on dilution may be explained on the basis of repulsive forces playing a significant role in solute-solvent interactions.     

Sol–gel synthesis and characterisation of nanoporous zirconium titanate coated on 316L SS for biomedical applications

In this study, the nanoporous zirconium titanate was prepared using sol–gel process and coated over 316L SS implants via dip-coating technique. XRD patterns of zirconium titanate are crystalline and orthorhombic in structure. FT-IR spectra showed a broad band between 3,500 and 3,300 cm⁻¹, which was assigned to fundamental stretching vibrations of hydroxyl groups. The set of overlapping peaks in the range of 810–520 cm⁻¹ are related to Zr–O and Zr–O–Ti groups. SEM-EDAX and TEM showed the surface morphology of coated zirconium titanate to be porous and uniform. Excellent adhesion of the coating to the substrate has been achieved. The contact angle value was found to be 12°. The coating acts as a barrier layer to the metallic implants and induces the formation of hydroxyapatite layer on the metal surfaces. These results revealed that the nano zirconium titanate coated 316L SS exhibit higher bioactivity compared to that of uncoated 316L SS.     

NH3 gas sensing properties of nanocrystalline ZnO based thick films

Zinc acetate derived precursor used in the present sol-gel synthesis of zinc oxide nanoparticles is described. The reaction product obtained before and after reflux of propanolic zinc acetate solution have been studied by UV-vis, photoluminescence and FT-IR studies which confirm the formation of oligomeric precursor Zn4O(Ac)6 (Ac=CH3COO). The formation of approximately 7 nm zinc oxide nanoparticles were confirmed by X-ray diffraction (XRD) and Transmission electron microscopic studies (TEM). The gaseous ammonia gas sensing characteristics of the nano-zinc oxide sensor showed high sensitivity compared to sensor fabricated with commercial zinc oxide powder.     

Perylene-3-ylmethanol: fluorescent organic nanoparticles as a single-component photoresponsive nanocarrier with real-time monitoring of anticancer drug release

We report for the first time the use of perylene-3-ylmethanol fluorescent organic nanoparticles as a drug delivery system. In the present system, perylene-3-ylmethanol nanoparticles performed four important roles: (i) "nanocarriers" for drug delivery; (ii) "phototriggers" for the drug release; (iii) fluorescent chromophores for cell imaging; and (iv) detectors for real time-monitoring of drug release. In vitro biological studies revealed that the newly developed perylene-3-ylmethanol nanoparticles exhibit good biocompatibility and cellular uptake as well as efficient photoregulated anticancer drug release ability. Such fluorescent organic nanoparticles may open up new perspectives for designing a new class of promising photoresponsive nanocarriers for drug delivery.     

Steady nonlinear hydromagnetic flow and heat transfer over a stretching surface of variable temperature

The steady nonlinear hydromagnetic flow of an incompressible, viscous and electrically conducting fluid with heat transfer over a surface of variable temperature stretching with a power-law velocity in the presence of variable transverse magnetic field is analysed. Utilizing similarity transformation, governing nonlinear partial differential equations are transformed to nonlinear ordinary differential equations and they are numerically solved using fourth-order Runge–Kutta shooting method. Numerical solutions are illustrated graphically by means of graphs. The effects of magnetic field, stretching parameter and Prandtl number on velocity, skin friction, temperature distribution and rate of heat transfer are discussed.     

Effect of Boundaries on Pattern Formation in a Monolayer of Interacting Dipoles

Self-organization can be defined as a process of arrangement of entities that start out in an irregular arrangement and evolve into a stable, regular pattern without the aid of an external agent. A system of magnetic particles that are constrained to move only in a plane is reported. The individual components in the system have dipole moments in an orientation perpendicular to the plane of motion and the interaction between components is purely repulsive. For such a system, it is attempted to understand the influence of the boundary of the monolayer on the patterns that emerge. A system with a small number of magnets is found where the range of the magnetic interactions is of the size of the boundary; the symmetry of the boundary imposed on the monolayer plays a crucial role in determining the pattern types, the number of different pattern types, and the frequency of appearance of a particular pattern type. The effect of scaling up the size of the system while maintaining the characteristics of individual components as well as the component areal density is also discussed.