Development and testing of impregnated La0.20Sr0.25Ca0.45TiO3 anode microstructures for solid oxide fuel cells

Funding: EPSRC project EP/M014304/1 “Tailoring of Microstructural Evolution in Impregnated SOFC Electrodes”, the University of St Andrews and HEXIS AG.The A-site deficient perovskite: La0.20Sr0.25Ca0.45TiO3 (LSCTA-) is a mixed ionic and electronic conductor (MIEC) which shows promising performance as a Solid Oxide Fuel Cell (SOFC) anode ‘backbone’ material, when impregnated with metallic and oxide-ion conducting electrocatalysts. Here, we present data on the complete ceramic processing and optimisation of the LSCTA- ‘backbone’ microstructure, in order to improve current distribution throughout the anode. Through control of ink rheology, screen printing parameters and sintering protocol an advantageous LSCTA- microstructural architecture was developed, exhibiting an ‘effective’ conductivity of 21 S cm-1. Incorporation of this LSCTA- anode microstructure into SOFC and impregnation with Ce0.80Gd0.20O1.9 and either Ni, Ru, Rh, Pt or Pd resulted in promising initial performances during fuel cell testing in a fuel stream of 97% H2:3% H2O. Area Specific Resistances of 0.41 Ω cm2 and 0.39 Ω cm2 were achieved with anodes containing Rh/CGO and Pd/CGO, respectively.Postprin

Durability of La0.20Sr0.25Ca0.45TiO3-based SOFC anodes : identifying sources of degradation in Ni and Pt/ceria co-impregnated fuel electrode microstructures

Funding from the University of St Andrews and HEXIS AG is acknowledged, in addition to the EPSRC Grants: EP/M014304/1 “Tailoring of Microstructural Evolution in Impregnated SOFC Electrodes” and EP/L017008/1 “Capital for Great Technologies”.Solid oxide fuel cells (SOFC) comprising LSM-YSZ/LSM composite cathodes, 6ScSZ electrolytes and La0.20Sr0.25Ca0.45TiO3 (LSCTA−) anode ‘backbone’ microstructures were prepared using thick-film ceramic processing techniques. Activation and decoration of the LSCTA− anode ‘backbone’ with electrocatalytic coatings of cerium-based oxides and metallic Ni or Pt particles was achieved using the technique of catalyst co-impregnation. SOFC containing Ni/CGO, Ni/CeO2 and Pt/CGO impregnated LSCTA anodes were tested up to ∼1000 hours by the Swiss SOFC manufacturer: HEXIS, under realistic operating conditions, including 15 redox, thermo and thermoredox cycles. The voltage degradation rates observed over the entire test period for the SOFC containing the Ni/CGO, Ni/CeO2 and Pt/CGO impregnated LSCTA− anodes were 14.9%, 7.7% and 13.4%, respectively. Post-mortem microscopic analyses indicated that CeO2 formed ubiquitous coatings upon the LSCTA− anode microstructure, allowing retention of a high population density of metallic (Ni) particles, whilst CGO formed ‘islands’ upon the microstructure and some agglomerates within the pores, leading to more facile agglomeration of metallic (Ni and Pt) nanoparticles. Correlation of the post-mortem microscopy with AC impedance analysis revealed that the agglomeration of metallic catalyst resulted in an increase in the high-frequency anode polarisation resistance, whilst agglomeration of the ceria-based component directly resulted in the development of a low-frequency process that may be attributed to combined contributions from gas conversion and chemical capacitance.PostprintPostprintPeer reviewe

Microstructure dependence of performance degradation for intermediate temperature solid oxide fuel cells based on the metallic catalyst infiltrated La- and Ca-doped SrTiO3 anode support

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement No. 256730 and Energy Technology Partnership (ETP). C. Ni also would like to thank the support from the Natural Science Foundation of China (NSFC, 51702264) Fundamental Research Funds for the Central Universities (XDJK2017B033) and Research Funding of Southwest University (SWU117019).Anode-supported solid oxide fuel cells with the configuration of the La0.2Sr0.25Ca0.45TiO3 (LSCTA-) anode, YSZ electrolyte and La0.8Sr0.2Co0.2Fe0.8O3 (LSCF)-YSZ cathode were fabricated using tape casting and co-sintering techniques followed by pre-reduction and impregnation. In order to improve the performance, the active anodes were prepared via the wet impregnation of metallic catalysts (Ni or Ni-Fe solution). The impregnation of 3 wt% nickel significantly improved the fuel cell performance from 43 mW cm-2 for the bare LSCTA- anode to 112 mW cm-2 for the Ni-LSCTA- anode at 700 °C in humidified hydrogen containing 3 vol% H2O. More interestingly, the substitution of 25 wt% Fe to Ni further enhances the power density by a factor of 1.5, compared to the Ni-impregnated cell. The cell infiltrated with Ni-Fe solid solution shows a slower degradation than the other two cells after the first 20 h period. High-resolution back-scattered electron (BSE) and transmission electron microscopy (TEM) images performed on the cross section of the impregnated anodes with time after ion beam preparation show that the sintering of the catalyst particles on the scaffold surface and the interaction between backbone and catalyst are the predominant contributions for the degradation of cell performance.PostprintPeer reviewe

Distribution of Brevetoxin (PbTx-3) in Mouse Plasma: Association with High-Density Lipoproteins

We investigated the brevetoxin congener PbTx-3 to determine its distribution among carrier proteins, including albumin and blood lipoproteins. Using a radiolabeled brevetoxin tracer (PbTx-3), we found that 39% of the radiolabel remained associated with components in mouse plasma after > 15 kDa cutoff dialysis. Of this portion, only 6.8% was bound to serum albumin. We also examined the binding of brevetoxin to various lipoprotein fractions. Plasma, either spiked with PbTx-3 or from mice treated for 30 min with PbTx-3, was fractionated into different-sized lipoproteins by iodixanol gradient ultracentrifugation. Each fraction was then characterized and quantified by agarose gel electrophoresis and brevetoxin radioimmunoassay, respectively. In both the in vitro and in vivo experiments, the majority of brevetoxin immunoreactivity was restricted to only those gradient fractions that contained high-density lipoproteins (HDLs). Independent confirmation of brevetoxin binding to HDLs was provided by high molecular weight (100 kDa cutoff) dialysis of [(3)H]PbTx-3 from lipoprotein fractions as well as a scintillation proximity assay using [(3)H]PbTx-3 and purified human HDLs. This information on the association of brevetoxins with HDLs provides a new foundation for understanding the process by which the toxin is delivered to and removed from tissues and may permit more effective therapeutic measures to treat intoxication from brevetoxins and the related ciguatoxins

Epidemiological, clinical and genetic aspects of adult onset isolated focal dystonia in Ireland

Background: Adult onset idiopathic isolated focal dystonia presents with a number of phenotypes. Reported prevalence rates vary considerably; well-characterized cohorts are important to our understanding of this disorder. Aim: To perform a nationwide epidemiological study of adult onset idiopathic isolated focal dystonia in the Republic of Ireland. Methods: Patients with adult onset idiopathic isolated focal dystonia were recruited from multiple sources. Diagnosis was based on assessment by a neurologist with an expertise in movement disorders. When consent was obtained, a number of clinical features including family history were assessed. Results: On the prevalence date there were 592 individuals in Ireland with adult onset idiopathic isolated focal dystonia, a point prevalence of 17.8 per 100 000 (95% confidence interval 16.4-19.2). Phenotype numbers were cervical dystonia 410 (69.2%), blepharospasm 102 (17.2%), focal hand dystonia 39 (6.6%), spasmodic dysphonia 18 (3.0%), musician\u27s dystonia 17 (2.9%) and oromandibular dystonia six (1.0%). Sixty-two (16.5%) of 375 consenting index cases had a relative with clinically confirmed adult onset idiopathic isolated focal dystonia (18 multiplex and 24 duplex families). Marked variations in the proportions of patients with tremor, segmental spread, sensory tricks, pain and psychiatric symptoms by phenotype were documented. Conclusions: The prevalence of adult onset idiopathic isolated focal dystonia in Ireland is higher than that recorded in many similar service-based epidemiological studies but is still likely to be an underestimate. The low proportion of individuals with blepharospasm may reflect reduced environmental exposure to sunlight in Ireland. This study will serve as a resource for international comparative studies of environmental and genetic factors in the pathogenesis of the disorder

Production and stability of low amount fraction of formaldehyde in hydrogen gas standards

Formaldehyde is an intermediate of the steam methane reforming process for hydrogen production. According to International Standard ISO 14687-2 the amount fraction level of formaldehyde present in hydrogen supplied to fuel cell electric vehicles (FCEV) must not exceed 10 nmol mol−1. The development of formaldehyde standards in hydrogen is crucial to validate the analytical results and ensure measurement reliability for the FCEV industry. NPL demonstrated that these standards can be gravimetrically prepared and validated at 10 μmol mol−1 with a shelf-life of 8 weeks (stability uncertainty <10%; k = 1), but that formaldehyde degrades into methanol and dimethoxymethane, as measured by FTIR, GC-MS and SIFT-MS. The degradation kinetics is more rapid than predicted by thermodynamics, this may be due to the internal gas cylinder surface acting as a catalyst. The identification of by-products (methanol and dimethoxymethane) requires further investigation to establish any potential undesirable impacts to the FCEV

Formal vs. informal coach education

The training of coaches is considered central to sustaining and improving the quality of sports coaching and the ongoing process of professionalisation. Sports coaches participate in a range of learning opportunities (informal to formal) that contribute to their development to varying degrees. In this article, we present our collective understanding on the varying types of learning opportunities and their contribution to coach accreditation and development. The authors presented these views (from a sports pedagogy perspective) as part of a workshop entitled "Formal vs. Informal Coach Education" at the 2007 International Council of Coach Education Master Class in Beijing. These reflections seek to stimulate the on-going, and often sterile, debate about formal versus informal coach education/learning in order to progress scholarship in coaching

Scaling up aqueous processing of A-site deficient strontium titanate for SOFC anode supports

The authors gratefully acknowledge funding from the Fuel Cells and Hydrogen Joint Undertaking under grant agreement n° 256730.All ceramic anode supported half cells of technically relevant scale were fabricated in this study, using a novel strontium titanate anode material. The use of this material would be highly advantageous in solid oxide fuel cells due to its redox tolerance and resistance to coking and sulphur poisoning. Successful fabrication was possible through aqueous tape casting of both anode support and electrolyte layers and subsequent lamination. Screen printing of electrolyte layers onto green anode tapes was also attempted but resulted in cracked electrolyte layers upon firing. Microstructural, electrical and mechanical properties of anode supports and half cells will be discussed. The use of two different commercial titanate powders with nominal identical, but in reality different stoichiometries, strongly affect electrical and mechanical properties. Careful consideration of such variations between powder suppliers, and batches of the same supplier, is critical for the successful implementation of ceramic anode supported solid oxide fuel cells.PostprintPeer reviewe

The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brain–behavior relationships after stroke

The goal of the Enhancing Neuroimaging Genetics through Meta‐Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well‐powered meta‐ and mega‐analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large‐scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided