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Byline: G. Lakshmi Narayana Rao, S. Saravanan, P. Selva Ilavarasi, G. Devasagayam Uncertainty in the availability of petroleum-based fuels in the near future and stringent pollution norms have triggered a search for renewable and clean-burning fuels. The use of vegetable oil as an alternative fuel has for long been in the pipeline, but its direct use has been limited because of its higher viscosity. In this work, sunflower oil was taken as feedstock and the feasibility of sunflower oil methyl ester (SFME) as an alternative fuel for diesel engines was investigated. Tests were conducted in a 4.4 kW, single cylinder, naturally aspirated direct injection diesel engine. It was observed that the premixed combustion phase of SFME and its blends were less intense compared with diesel oil. In addition, it was observed that SFME and its blends had slightly lower thermal efficiency and lower tailpipe emissions than diesel oil.

Byline: G. Lakshmi Narayana Rao, N. Nallusamy, S. Sampath, K. Rajagopal Biodiesel derived from vegetable oils and animal fats can be used in diesel engines with little or no modifications. In this work, the combustion, performance and emission characteristics of various biodiesel (rice bran oil and pungam oil) and their blends are evaluated in a direct injection diesel engine. Lower ignition delay, higher peak pressure and heat release rate with almost same brake thermal efficiency are obtained for 20% biodiesel blend as compared with diesel fuel. They exhibited lower unburned hydrocarbon, carbon monoxide and soot emissions with a penalty of higher NOx emissions.

A tunable interdigitated capacitor is developed using Ba0.5Sr0.5TiO3 ferroelectic thin film and low-k fused silica substrate for applications in the microwave frequency range. The capacitance and quality factor of tunable IDC structure on BST5 film as a function of frequency up to 5 GHz are extracted using the conformal mapping method and partial capacitance technique. In this paper, the tunable capacitance properties of Au/Ba0.5Sr0.5TiO3 thin-film interdigital capacitors on low-k substrates are presented. [ABSTRACT FROM AUTHOR]

Polycrystalline samples of (Zr0.8Sn0.2)TiO4 have been synthesised by solid state reaction method. The effects of ball milling and the addition of ZnO (1–2.5 wt-%) on the microwave dielectric properties of (Zr0.8Sn0.2)TiO4 ceramics are investigated. As the ball milling time increases, the density of the (Zr0.8Sn0.2)TiO4 ceramics increases. The influence of ZnO as a sintering aid on the sintering temperature of (Zr0.8Sn0.2)TiO4 is also studied. As the weight percentage of ZnO increases, the density increases up to 1.5 wt-% of ZnO and thereafter it starts decreasing. The dielectric constant εr and the product of quality factor Q and resonant frequency fo of TE01δ mode (Qxfo) followed the same trend with increasing density, irrespective of whether the density increased with ball milling time or by addition of ZnO. The value of Qxfo is found to increase with increasing grain size. The microwave dielectric constant and the Qxfo values were respectively ranged from 32 to 39.3 and from 32 000 to 49 600 at 10.5 GHz for (Zr0.8Sn0.2)TiO4 ceramics. Furthermore, the influence of the processing parameters on the microwave dielectric properties of (Zr0.8Sn0.2)TiO4 is discussed. [ABSTRACT FROM AUTHOR]