Preparation, characterization and electrical conductivity studies of nanocrystalline La doped BaMoO4

Different compositions of scheelite type nanocrystalline La doped BaMoO₄ [Ba_1−xLa_xMoO_4+x/2, where x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5] samples were prepared by acrylamide assisted sol-gel combustion process. Dried gels prepared at 60 °C were heated at different temperatures and characterized using TG/DTA, XRD, FTIR and SEM-EDX techniques. From XRD patterns, crystalline phases for La doped BaMoO₄ samples were confirmed and their average crystallite sizes were calculated using Scherrer's formula and it was found to be less than 80 nm. Structure and thermal behavior of scheelite type nanocrystalline La doped BaMoO₄ samples were identified respectively using FTIR and TG/DTA measurements. Microstructure and existence of O, La, Ba and Mo elements in the La doped BaMoO₄ samples were obtained from SEM-EDX and HRTEMtechniques. The ‘d’ spacing values were obtained for different (h k l) planes and were well matched with the standard BaMoO₄. (h k l) values for different directions of planes were assigned for the observed HRTEM images and were matched with standard BaMoO₄. Grain and grain boundary conductivities were evaluated by analyzing the impedance data, using the Winfit software, measured at different temperatures.     

An optimized pretreatment method in the analysis of negative plate of lead acid battery

The composition of the plate in lead acid battery plays a vital role on battery performance. Therefore, controlling and monitoring of plate composition is utmost important in order to attain required battery performance. While monitoring negative plate, it has to be ensured that they are not exposed to air, which would otherwise result in Pb oxidation; thereby affecting the accuracy of the test data. Nevertheless, published information is scarce on the “pretreatment and preservation of the negative plates”. The objective of this study is to develop a suitable procedure to “preserve and pretreat the negative plate” prior to chemical composition analysis. A host of experimental parameters like immersion time in water, effect of drying reagent and air drying time were studied. Two drying solvents; namely, methanol and acetone were studied to evaluate their suitability.     

Electrical conductivity studies of nanocrystalline lanthanum silicate synthesized by sol-gel route

Nanocrystalline apatite type structured lanthanum silicate (La₁₀Si₆O₂₇) sample was synthesized by sol-gel process. Thermal behavior of the dried gel of lanthanum silicate sample was studied using TG/DTA. The structural coordination of the dried gel of lanthanum silicate, calcined at various temperatures, was identified from the observed FTIR spectral results. The observed XRD patterns of the calcined dried gel were compared with the ICDD data and confirmed the formation of crystalline lanthanum silicate phase. The average crystalline size of La₁₀Si₆O₂₇ was calculated using the Scherrer formula and it is found to be ∼80 nm. The observed SEM images of the lanthanum silicate indicate the formation of the spherical particles and the existence of O, Si and La in the lanthanum silicate are confirmed from the SEM-EDX spectrum. The grain and grain boundary conductivities are evaluated by analyzing the measured impedance data, using winfit software, obtained at different temperatures, of La₁₀Si₆O₂₇ sample. Also, the observed grain and grain boundary conductivity behaviors of the La₁₀Si₆O₂₇ sample are analysed using brick layer model. The electrical permittivity and electrical modulus were calculated from the measured impedance data and were analyzed by fitting through the Havriliak and Negami function to describe the dielectric relaxation behavior of the nanocrystalline lanthanum silicate.     

Machines, Tools and Tool Transporter Concurrent Scheduling in Multi-machine FMS with Alternative Routing Using SymbioticOrganisms Search Algorithm

This study explored the concurrent scheduling of machines, tools, and tool transporter(TT) with alternative machines in a multi-machine flexible manufacturing system(FMS), taking into mind the tool transfer durations for minimization of the makespan(MSN). When tools are expensive, just a single copy of every tool kind is made available for use in the FMS system. Because the tools are housed in a central tool magazine(CTM), which then distributes and delivers them to many machines, because there ...