Perovskite SrFe1-xTixO3-δ (x < = 0.1) cathode for low temperature solid oxide fuel cell

© 2018 Elsevier Ltd and Techna Group S.r.l. Stable and compatible cathode materials are a key factor for realizing the low-temperature (LT, ≤600 °C) operation and practical implementations of solid oxide fuel cells (SOFCs). In this study, perovskite oxides SrFe 1-x Ti x O 3-δ (x < = 0.1), with various ratios of Ti doping, are prepared by a sol-gel method for cathode material for LT-SOFCs. The structure, morphology and thermo-gravimetric characteristics of the resultant SFT powders are investigated. It is found that the Ti is successfully doped into SrFeO 3-δ to form a single phase cubic perovskite structure and crystal structure of SFT shows better stability than SrFeO 3-δ . The dc electrical conductivity and electrochemical properties of SFT are measured and analysed by four-probe and electrochemical impedance spectra (EIS) measurements, respectively. The obtained SFT exhibits a very low polarization resistance (R p ),.01 Ωcm 2 at 600◦C. The SFT powders using as cathode in fuel cell devices, exhibit maximum power density of 551 mW cm −2 with open circuit voltage (OCV) of 1.15 V at 600◦C. The good performance of the SFT cathode indicates a high rate of oxygen diffusion through the material at cathode. By enabling operation at low temperatures, SFT cathodes may result in a practical implementation of SOFCs

Transesterification of Low-Quality Triglycerides over a Zn/CaO Heterogeneous Catalyst: Kinetics and Reusability Studies

Zinc-doped (0.25–7 wt %) calcium oxide (Zn/CaO) has been prepared in nanocrystalline form by a simple wet chemical method followed by calcination up to 950 °C. The structural analysis has been investigated by powder X-ray diffraction (XRD), whereas the surface morphology and average particle size of Zn/CaO were determined by scanning electron and transmission electron microscopic studies, respectively. The catalytic activity of the prepared Zn/CaO toward the transesterification of cotton seed oil with methanol was found to be a function of its calcination temperature, crystallite size, and basic strength. A pseudo-first-order kinetic model was applied to evaluate the kinetic parameters for the transesterification of waste cotton seed oil with methanol, and a first-order rate constant (<i>k</i>) and activation energy (<i>E</i>_a) were found to be 0.10 min^–1 and 43 kJ mol^–1, respectively. The catalyst, Zn/CaO, was amenable to recovery and recycling for at least five consecutive reaction cycles. The Koros–Nowak criterion test has been employed to demonstrate that measured catalytic activity was independent of the influence of transport phenomenon. Further, Zn/CaO was also found as an efficient catalyst for the complete transesterification of a variety of triglycerides (having up to 8.4 wt % free fatty acids), such as virgin cotton seed oil, soybean oil, waste cotton seed oil, castor oil, karanja oil, jatropha oil, and mutton fat. Thus, the present work demonstrates the application of high free fatty acid containing waste or non-edible oils as feedstock, without any pre-treatment, for biodiesel production

Ti/SiO₂ as a Nanosized Solid Catalyst for the Epoxidation of Fatty Acid Methyl Esters and Triglycerides

The chemical method has been employed to prepare a series of titanium-loaded silica (1.7 wt % Ti on SiO₂), followed by calcination in the temperature range of 550–950 °C. Diffuse reflectance solid-state ultraviolet–visible spectroscopy supported the incorporation of TiO₂ on the silica support and existence of titanium in distorted tetrahedral and octahedral environments. The surface morphology and particle size of Ti/SiO₂ were observed by field emission scanning electron microscopic and transmission electron microscopic techniques and later support the formation of 20–100 nm sized Ti/SiO₂ particles. Prepared Ti/SiO₂ has been employed as a solid catalyst for the epoxidation of fatty acid methyl esters, derived from used cotton seed oil, under two different reaction conditions, viz., (i) H₂O₂ and formic acid and (ii) H₂O₂, acetonitrile, and butyronitrile in the presence of ultraviolet radiation. To demonstrate the versatility of the prepared Ti/SiO₂ catalyst, it was also successfully employed for the epoxidation of a variety of substrates, viz., methyl oleate, used cotton seed oil, and fatty acid methyl esters obtained from soybean, Karanja, and Jatropha oils. Under optimized reaction conditions in both methods, the prepared Ti/SiO₂ catalyst afforded a high epoxide yield (100%) even at room temperature (35 °C). The catalyst was amenable to recovery and recycling for at least five consecutive reaction cycles with the partial loss of activity after every successive run. Finally, the synthesized epoxidized fatty acid methyl esters have been tested as lubricity improver additives for diesel fuel

Design, semi-synthesis of soft coral-derived <i>Aspergillus</i> sp. secondary metabolite geodin derivatives and their antibacterial activities

A series of novel ester derivatives 2 − 7, of natural product geodin 1, isolated from the soft coral-derived fungus Aspergillus sp., were designed and semi-synthesised through one step reaction with high yield. Compound 5 showed strong antifouling inhibitory activities with MIC of 4.80 μM while compound 4 showed selective inhibitory activities with MICs values 8.59 μM against Aeromonas salmonicida and Pseudomonas aeruginosa (Sea-Nine 211, MIC = 0.27 μM). Compounds 3, 4 and 6 showed potent anti-pathogenic inhibitory activities with MICs of 2.29 μM, 4.29 μM and 4.56 μM respectively against Staphylococcus aureus (Ciprofloxacin, MIC = 0.156 μM). Compound 2 showed weak inhibitory activity against A. salmonicida with MIC 18.75 μM (Sea-Nine 211, MIC = 0.27 μM) and with MICs 9.38 μM against S. aureus (ciprofloxacin, MIC = 0.156 μM). However, compound 7 showed very low antibacterial activities with MIC = >20 μM. The preliminary structure-activity relationships of compounds 2 − 7 further prove that the modification of 4-OH group of natural product geodin 1 improves the antibacterial activities such as antifouling and anti-pathogenic activities.</p

A Novel Procedure for the Synthesis of Epoxides: Application of Simmons−Smith Reagents toward Epoxidation

A Novel Procedure for the Synthesis of Epoxides:  Application of Simmons−Smith Reagents toward Epoxidatio

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Additional file 6: Fig. S3. Structural and functional properties of potential biomarker candidates. Studies of macromolecular interfaces using PDBePISA interactive tool. Motif scan in protein sequences were studied using Motif tool. Identified gapped approximate repeats and complex repeat architectures using RADAR (Rapid Automatic Detection and Alignment of Repeats) tool

Diastereoselective 1,6-Addition of α‑Phosphonyloxy Enolates to <i>para</i>-Quinone Methides

The addition of α-ketoamide to p-quinone methide initiated by dialkylphosphite in the presence of organic base 1,8-diazabicyclo(5.4.0)­undec-7-ene (DBU) is explored. Coupling of dialkylphosphites to α-ketoamides in the presence of a base follows [1,2]-phospha-Brook rearrangement, generating corresponding α-phosphonyloxy enolates that are subsequently seized by p-quinone methides (p-QMs). The two-step one-pot 1,6-conjugate addition provides effective access to a series of isatin-incorporated phosphate-bearing 1,6-adducts having two vicinal tertiary carbons with up to 90% yield and >20:1 dr

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Additional file 7: Fig. S4. Data mapping: The role of differentially expressed genes in alopecia was mapped using the Comparative Toxicogenomics Database (CTD)

MOESM2 of A systematic simulation-based meta-analytical framework for prediction of physiological biomarkers in alopecia

Additional file 2: Table S1. The function summaryAffyRNAdeg of Bioconductor package produced a single summary-statistic for each array in the batch dataset