Abstract: In this study, a systematic investigation on in-situ sintering behavior of Ni-YSZ (50: 50wt. %) pellets of density of 4.2 (low density) and 4.9 g/cm3 (high density) in ambient and oxygen environment by impedance spectroscopy is presented. X-ray diffraction indicated the formation of cubic phases of NiO and YSZ. The low density pellet sintered for 16 h showed low content of monoclinic phase when compared to high density pellet. The microstructure of the high density pellet revealed finer and homogenous distribution of Ni in YSZ matrix due to longer sintering duration when compared with the low density pellet. AC impedance spectra were recorded for both low and high density pellets during sintering in ambient and oxygen environment in the temperature range 873-1173 K. The results indicate that for both the pellets, the impedance values decreased when sintering temperature increased from 873 to 1173 K in both ambient and oxygen environment. However, the impedance was low while sintering in oxygen atmosphere than in ambient. Besides these observation, impedance of the high density pellet was much lower than that of the low density pellet at all sintering temperature in both ambient and oxygen atmosphere. While the impedance decreased with increasing sintering temperature, the capacitance increased slowly in both the ambient and oxygen atmosphere. The change in the impedance behavior due to grain interior and grain boundaries is explained in relation with the microstructural changes that occur during sintering in different environments.
Abstract: The recent development of nanoparticles in commercial media has great attention due to uniformity and stability of the materials. In our present investigation cadmium sulfide (CdS), a direct bandgap semiconductor material has well defined optoelectronic properties in the applications of photocatalysis, photoelectrocatalytic and nonlinear optics. Zeolite which offers a perfect host material for the production of highly uniform nanoparticles with apparently circulated provisions and inhibiting the aggregation of nanoparticles and also helps in the protection from the attack by water and other reactive compounds. In order to stabilize the CdS nanoparticles and to prevent their aggregations, CdS is sheltered within the zeolite Y material. This novel assembly was synthesized by ion exchange method. In order to increase the photocatalytic activity of CdS, ZnO nanoparticles were incorporated into the zeolite Y assembly. The photocatalytic activity of the CdS/ZnO-Y towards the degradation of methyl orange was investigated under the visible light; it follows pseudo first order kinetics. After incorporation the composite loaded assembly (CdS/ZnO-Y) exhibits a superior photocatalytic activity due to the suppressed recombination rate of photogenerated charge carriers due to the synergy between the two semiconductor species. The as synthesized sample was characterized by UV DRS, FTIR and PL techniques.
Abstract: The modern world needs an innovative solution in the non-renewable energy field, because of its excessive usage. Due to rapid reduction of non-renewable energy sources, along with rising demand for energy is a matter of serious concern. This paper provides a better solution for this non-renewable energy problem. It is a hybrid technique in the energy field with good quality by decreasing the pure content and increase the subordinate content which must have the similar property of pure content. Biodiesel generally derived from the biological source and it can be used as an alternative fuel for diesel engines, because it has certain unique property like diesel. Biodiesel can be used as a direct replacement of diesel fuel or it also can be used as a blending element for diesel fuel in a compression ignition engines. In this paper, the biofuel called Calophyllum Inophyllum oil can be effectively blended with diesel through transesterification process. The Calophyllum Inophyllum blended with diesel at various proportions such as 20%, 40%, 60%, and 80% are tested for performance and emissions in a single cylinder variable compression ratio four stroke diesel engine test rig. The experimental results show that for 80% blend with a compression ratio of 18:1 has increased the performance of the engine, particularly the brake thermal efficiency and the CO and smoke emission levels are also found to be reduced considerably when compared to existing diesel fuel.