Degradation Comparison of Cyclic and Linear Siloxane Contamination on Solid Oxide Fuel Cells Ni-YSZ Anode

The solid oxide fuel cell (SOFC) nickel-yttria stabilized zirconia (Ni-YSZ) anode degradation due to different types of siloxane contamination is investigated. A cyclic structure siloxane, octamethylcyclotetrasiloxane (D4), and a linear structure siloxane, decamethyltetrasiloxane (L4), are mixed with H2+N2 as the fuel for SOFCs at 750°C. The electrochemical characterization results after stability experiments suggest that the SOFC contaminated with cyclic siloxane, D4, had higher degradation. Pure YSZ pellets with different surface hydroxylation extents were also tested to investigate the D4/L4 adsorption and deposition process. Postmortem SEM/WDS, XRD and Raman analysis all indicate that cyclic siloxane has more deposition than linear siloxane on the anode. Further analysis demonstrates that high adsorption and low desorption rates of cyclic siloxane on YSZ are linked to the degradation. Besides the silicon deposition, SiC and amorphous carbon deposition were also observed from the XRD and Raman analysis.

Cyclic Siloxane Biosurfactant Producing Bacillus Sp. BS14 Biocontrol Charcoal Rot Pathogen Macrophomina Phaseolina and Induce Growth Promotion in Vigna Mungo L.

Rhizobacteria are important component of soil-plant interfaces and help in the management of plant diseases by various means. Precisely, the role of biosurfactant is underscored in biocontrol. The current study showed the exploration of biosurfactant-producing bacteria and its effect in indirect reduction of disease severity in pulse crops. In this study, BS14 was screened as plant growth promoting, biosurfactant producing and biocontrol agent against Macrophomina phaseolina. The biosurfactant purified for biocontrol assays and shown inhibition of fungal hyphal growth in dual culture method and cellular-level deformities in mycelia of M. phaseolina, as observed under scanning electron microscopic (SEM). The biosurfactant of Bacillus BS14 was identified as cyclic siloxane in GC-MS-spectroscopy and FTIR-spectroscopy analysis. In pot-trial studies Bacillus sp. BS14 proved their efficiency for the growth-promotion of Vigna mungo and significant reduction in disease severity index. Using biosurfactants is a biological alternative to the control of plant diseases.

Synthesis of multifunctional liquid crystalline epoxy resin embedded cyclic-siloxane chain with Tg-less behavior and enhanced toughness

A novel tetrafunctional mesogenic epoxy monomer with a cyclic-siloxane chain as a central part was successfully synthesized and characterized by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, differential scanning calorimetry, and polarized optical microscopy. The transition temperature and liquid crystallinity of cyclic-siloxane type mesogenic epoxy were compared with those of linear-siloxane type mesogenic epoxy. Moreover, epoxy thermosets were prepared based on the cyclic- and linear-siloxane type mesogenic epoxy monomers and 4,4′-diaminodiphenylethane. The effects of epoxy backbone moiety on thermal and mechanical properties were investigated in detail. As a result, the cyclic-siloxane type mesogenic epoxy thermoset shows glass transition temperature-less behavior and low coefficient of linear thermal expansion without a decrease in toughness.