Synthesis Of Nanoparticle Barium Hex Aferrite By Sol Gel Auto Combutio

Nanocrystalline of Barium Hexaferrite (BaFe12O19) powders have been synthesized using the sol gel auto combustion method. The ferrite precursors were obtained from aqueous mixtures of Barium nitrate and Ferric nitrate by auto combustion reaction from gel point. These precursors were sintered at different temperatures ranging from 700 to 1000oC for constant calcinations time 2,5 h in a static air atmosphere. Effects of Fe3+/Ba2+ mol ratios and sintering temperatures on the microstructure and magnetic properties were systematically studied. The powders formed were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and VSM. The results obtained showed that the phase BaFe12O19 powders were achieved by the Fe3+/Ba2+ mole ratio from the stoichiometric value 11, 11.5 and 12 at temperature 950OC. With increasing of temperature sintering, coercivity and magnetization value tends to rising. The maximum saturation magnetization (66.16 emu/g) was achieved at the Fe3+/Ba2+ mole ratio to 11.5 and the sintering temperature 950OC. The maximum coercivity value 3542 Oe achieved at mole ratio sample 12 with sintering temperature 950OC. Maximum saturation 6616 emu/g achieved at mole ratio sample 115 with the same temperature

Prokaryotic Hydrocarbon Degraders

Hydrocarbons have been part of the biosphere for millions of years, and a diverse group of prokaryotes has evolved to use them as a source of carbon and energy. To date, the vast majority of formally defined genera are eubacterial, in 7 of the 24 major phyla currently formally recognized by taxonomists (Tree of Life, http://tolweb.org/Eubacteria. Accessed 1 Sept 2017, 2017); principally in the Actinobacteria, the Bacteroidetes, the Firmicutes, and the Proteobacteria. Some Cyanobacteria have been shown to degrade hydrocarbons on a limited scale, but whether this is of any ecological significance remains to be seen – it is likely that all aerobic organisms show some basal metabolism of hydrocarbons by nonspecific oxygenases, and similar “universal” metabolism may occur in anaerobes. This chapter focuses on the now quite large number of named microbial genera where there is reasonably convincing evidence for hydrocarbon metabolism. We have found more than 320 genera of Eubacteria, and 12 genera of Archaea. Molecular methods are revealing a vastly greater diversity of currently uncultured organisms – Hug et al. (Nat Microbiol 1:16048, 2016) claim 92 named bacterial phyla, many with almost totally unknown physiology – and it seems reasonable to believe that the catalog of genera reported here will be substantially expanded in the future