Self-assembled tungsten oxide nanowires by electron beam assisted rapid thermal annealing

We report on the fabrication of WO₃ nanowires on Si (100) substrate using nickel catalyzed electron beam assisted rapid thermal annealing process. A 7 nm thick W layer deposited on the nickel coated substrate was annealed under high vacuum using electron beam (3 keV) for 30, 60 and 90 s. The nickel activates the growth of tungsten nanowires with a high aspect ratio and subsequently is oxidized due to the high refractory nature of tungsten under exposure to oxygen gas. The resulting changes in surface morphology, oxidization state and elemental composition of WO₃ nanowires were investigated systematically. The oxidization of metallic tungsten nanowire was found to depend on the annealing time.     

Plasma-Sprayed Ceramic Reaction Couples

In preparing specimens for studying reaction kinetics, it is essential to ensure proper contact between couple end-members. In the present work, reaction couples were prepared by spraying layers of the end-member materials over one another. This method has many advantages, including precise control over the properties of the end-members.     

Light screening effects of photoinitiators in UV curable systems

The effect of initiator concentration and sample thickness on the photocuring properties of acrylate and methacrylate monomers has been investigated. It has been shown that as the concentration of photoinitiator increases the degree of polymerisation reaches a maximum and then decreases. This effect is very marked for film thicknesses greater than 1 mm. The optimum level of initiator corresponding to a maximum cure decreases as the sample depth increases. Photoinitiators with a high extinction coefficient at the principal wavelength of the UV source give rise to optimum concentrations at lower initiator levels. It should therefore be possible to predict the appropriate initiator concentration for a particular film thickness.     

Internetworking framework in underwater wireless sensor network protocol to a certain connectivity using probabilistic approaches

Microsystem Technologies - Ocean acidification is one of the parameters that affect underwater wireless sensor network routing protocols. The underlying network-level metrics of sensor nodes...     

Pre-treatment of high oil and grease pet food industrial wastewaters using immobilized lipase hydrolyzation

Wastewaters generating from pet food industries contain high concentration of oil and grease (O&G), which is difficult to treat through conventional biological treatment systems. In this study, the hydrolysis of O&G originating from pet food industrial wastewater was evaluated. Candida rugosa lipase was immobilized in calcium alginate beads and applied in the hydrolysis experiment. Results showed that approximately 50% of the O&G was hydrolyzed due to the enzyme activity. A significant increment in COD and VFA production was also observed. The immobilized lipase activity was confirmed with p-nitrophenyl palmitate (pNPP) before and after O&G hydrolysis. During the 3-day experiment, approximately 65% of the beads were recovered and after the hydrolysis, approximately 70% of the enzyme activity remained in the beads. This study shows the potential of immobilized lipase as a pre-treatment step in biological treatment of pet food manufacturing wastewater.     

Removal of iron from drinking water by electrocoagulation: Adsorption and kinetics studies

The present study provides an electrocoagulation process for the removal of iron from drinking water with aluminum alloy as the anode and stainless steel as the cathode. The studies were carried out as a function of pH, temperature and current density. The adsorption capacity was evaluated with both the Langmuir and the Freundlich isotherm models. The results showed that the maximum removal efficiency of 98.8% was achieved at a current density of 0.06 A dm⁻², at a pH of 6.5. The adsorption of iron preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The adsorption process follows second-order kinetics. Temperature studies showed that adsorption was endothermic and spontaneous in nature.     

Nanomaterial Deposits Formed by DC Plasma Spraying of Liquid Feedstocks

An experimental system consisting of an axial feed plasma gun, a variable-rate liquid delivery system, a liquid atomizer-feeder, and a substrate movement and control system was designed and assembled for preparing nanograined ceramic deposits. Sprayed deposits were produced with different spray and sol feed parameters and investigated in both the as-sprayed and heat-treated conditions. As-sprayed deposits were predominately hydroxide phases and were strongly adherent to the substrates. Postspray heat treatment at 873 K led to conversion of the alumina and zirconia deposits to γ-alumina and tetragonal zirconia phases, respectively. Subsequent heat treatment at 1273 K resulted in densification of the deposits and formation of high-temperature phases. A small increase in the grain size was observed with heat treatment, but the specimens still retained nanosized grains.