Investigations on the photocatalytic activity of sol–gel derived plain and Fe/Nb-doped titania coatings on glass substrates

Plain and doped (Fe³⁺ and Nb⁵⁺) titania coatings were deposited by dip coating on soda lime glass substrates using titania sol synthesized by sol–gel route in combination with commercial nanoparticle dispersions. The dopant concentrations were fixed at 0.07 wt% and the coatings heat treated at 400 °C were characterized with respect to their thickness, phase composition, hydrophilicity/hydrophobicity and microstructure. Photocatalytic activity testing was carried out on the coatings by following up the degradation of methylene blue dye for up to 4 h at 1 h time intervals after exposure to sunlight. The effect of a trivalent and pentavalent doping of Ti⁴⁺ sites on photocatalytic activity of TiO₂ was investigated.     

Chemical bath deposition of SnS thin films on ZnS and CdS substrates

We illustrate that Tin sulfide (SnS) thin films of 110–500 nm in thickness may be deposited on ZnS and CdS substrates to simulate the requirement in developing window-buffer/SnS solar cells in the superstrate configuration. In the chemical bath deposition reported here, tin chloride and thiosulfate are the major constituents and the deposition is made at 25 °C. In a single deposition, film thickness of 110–170 nm is achieved and in two more successive depositions, the film thickness is 450–500 nm. The thicker films are composed of vertically stacked flakes, 100 nm across and 10–20 nm in thickness. The Sn/S elemental ratio is ~1 for the films 110–170 nm in thickness, but it slightly increases for thicker films. The crystalline structure is orthorhombic, similar to the mineral herzenbergite, and with crystallite diameters 13 nm (110–170 films) and 16 nm (450–500 nm films). The Raman bands at 94, 172 and 218 cm^?1 further confirm the SnS composition of the films. The optical band gap of SnS is 1.4–1.5 eV for the thinner films, but is 1.28–1.39 eV for the thicker films, the decrease being ascribed to the increase in the crystallite diameter. Uniform pin-hole free SnS thin films were successfully grown on two different substrates and can be applied in solar cell structures.     

Characterization of shape memory behaviour of CTBN-epoxy resin system

The temperature-responsive poly(vinyl alcohol)/ poly(N-isopropylacrylamide) hydrogel was prepared as a drug delivery carrier. The vitamin B12 release behavior of hydrogel was controlled by direct oxyfluorination. The oxyfluorination of hydrogel changed the surface characteristics to have hydrophilic functional groups. On the other hand, the hydrophobicity of hydrogel increased by fluorination treatment due to the induced hydrophobic functional groups. C-O bond and C-F bond were mainly formed by oxyfluorination and fluorination, respectively. The surface morphology showed the significant variation depending on the oxyfluorination conditions. Both swelling ratio and drug release rate were strongly dependent on the oxyfluorination conditions. The swelling of hydrogel increased further by the surface modification with oxyfluorination in a higher oxygen content to give more hydrophilic properties. The drug release from hydrogel also increased as more hydrophilic functional groups were introduced by oxyfluorination because the favorable affinity at the interface resulted in a higher swelling ratio. On the other hand, the relatively low swelling ratio and slower drug release from hydrogel were observed with more hydrophobic functional groups introduced by fluorination.     

Immobilization of ZnO on Chitosan-Neem seed composite for enhanced thermal and antibacterial activity

Natural and inorganic materials of Chitosan-Zinc oxide-Neem seed (CS-ZnO-NS) hybrid composite were synthesized by chemical precipitation method. The obtained CS-ZnO-NS hybrid composites were characterized for functional group confirmation by Fourier transform infrared spectroscopy and UV–Visible spectroscopy. The ZnO particles connected to biopolymers exhibited small grains and rod, bullet like structure confirmed by scanning electron microscopy and transmission electron microscopy analysis. The size of the prepared CS-ZnO-NS hybrid composite was found to be 20–80?nm. The crystalline behaviors were determined by X-ray diffraction analysis. The surface area of the prepared hybrid composite was determined using BET analysis. The elemental composition was analyzed by energy dispersive X-ray spectroscopy and thermal behaviors by thermo gravimetric analysis. The obtained result shows that zinc oxide was well able to incorporate into chitosan-neem seed composite which enhances the thermal stability. Further, the antibacterial activity evaluated by agar well diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria exhibits higher inhibition effect because of ZnO particles presence in the chitosan-neem seed. Hence the CS-ZnO-NS is a promising material for biomedical applications.     

An attribute-based lightweight cloud data access control using hypergraph structure

The Journal of Supercomputing - Cloud file storage systems are the current trend of enterprises and also of individual users. Due to the malicious or unauthorized users, file sharing among the...     

Boron Deteriorates the Thermal Stability of Nanostructured Silicon

Silicon - Guided by Darling et al. model for nanostructure stability, Boron was chosen for stabilizing nanostructured silicon. The Si-4 at.% B alloy was synthesized by high energy ball...