384 research outputs found
Development and testing of impregnated La0.20Sr0.25Ca0.45TiO3 anode microstructures for solid oxide fuel cells
Funding: EPSRC project EP/M014304/1 âTailoring of Microstructural Evolution in Impregnated SOFC Electrodesâ, 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 âbackboneâ material, when impregnated with metallic and oxide-ion conducting electrocatalysts. Here, we present data on the complete ceramic processing and optimisation of the LSCTA- âbackboneâ 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 âeffectiveâ 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
Development and testing of impregnated La0.20Sr0.25Ca0.45TiO3 anode microstructures for solid oxide fuel cells
Funding: EPSRC project EP/M014304/1 âTailoring of Microstructural Evolution in Impregnated SOFC Electrodesâ, 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 âbackboneâ material, when impregnated with metallic and oxide-ion conducting electrocatalysts. Here, we present data on the complete ceramic processing and optimisation of the LSCTA- âbackboneâ 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 âeffectiveâ 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
Assessment of pipeline stability in the Gulf of Mexico during hurricanes using dynamic analysis
AbstractPipelines are the critical link between major offshore oil and gas developments and the mainland. Any inadequate on-bottom stability design could result in disruption and failure, having a devastating impact on the economy and environment. Predicting the stability behavior of offshore pipelines in hurricanes is therefore vital to the assessment of both new design and existing assets. The Gulf of Mexico has a very dense network of pipeline systems constructed on the seabed. During the last two decades, the Gulf of Mexico has experienced a series of strong hurricanes, which have destroyed, disrupted and destabilized many pipelines. This paper first reviews some of these engineering cases. Following that, three case studies are retrospectively simulated using an in-house developed program. The study utilizes the offshore pipeline and hurricane details to conduct a Dynamic Lateral Stability analysis, with the results providing evidence as to the accuracy of the modeling techniques developed
The influence of diet and physical activity on bone density of children aged 5-7 years: The Belfast HAPO family study
ObjectiveOsteoporosis is a global health issue, and modifiable behavioural factors need to be identified in childhood to reduce the risk of osteoporosis in later life. The aim of this study was to investigate the influence of diet and physical activity on bone density of children aged 5â7 years participating in the Belfast Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) Family study.Design and methodsPregnant women were recruited to the Belfast centre of the HAPO study at 24â32 weeks gestation. Offspring were followed up at 5â7 years as part of the Belfast HAPO Family Study. Heel bone mineral density (BMD) and bone mineral apparent density (BMAD) were measured and calculated, respectively. Physical activity in the offspring was measured by accelerometery and dietary intakes were measured using a 4-day food diary.ResultsResults from 793 offspring were analysed. Mean age of the offspring ± standard deviation was 6.4 ± 0.5 years. A mean of 48.3 ± 22.4 min each day was spent in moderate to vigorous physical activity (MVPA). Median (interquartile range) dietary calcium and vitamin D intakes were 844 (662â1073) mg/day and 1.7 (1.1â2.5) ÎŒg/day, respectively. Neither dietary vitamin D nor calcium intakes were significantly associated with offspring heel BMD or BMAD in multiple regression. However, controlling for confounders, a 30-min greater MVPA was associated with significantly larger heel BMD (0.018 g/cm2 in boys and 0.010 g/cm2 in girls) and BMAD (0.005 g/cm3 in boys and 0.003 g/cm3 in girls).ConclusionPhysical activity was associated with better BMD and BMAD in 5â7-year-old children. Dietary calcium and vitamin D were not predictive of BMD and BMAD
OMAE2009-79934 JACK-UP INSTALLATION ON AN UNEVEN SEABED: RECOMMENDATIONS FROM MODEL TESTING IN OVERCONSOLIDATED CLAY
ABSTRACT This paper presents results of a laboratory testing program employing a reduced-scaled model of a three-legged jack-up to investigate the influence of an adjacent footprint on spudcan installation. This study focused on the installation of the full jack-up with a single leg located adjacent to a surface discontinuity. This contrasts previous studies that focused on the behavior of a single leg model and aims to account for the coupled interaction of the three legs and hull. The investigation was conducted using a 1:200 model scale jack-up designed to represent an average commonly used field jack-up. It was fully instrumented for leg bending and axial force measurement, and allowed unconstrained horizontal motion and rotation in the plane of foundation-footprint offset. Installation was performed at foundation-footprint centerline offsets of 0.75, 0.89, and 1.0 times the footprint diameter in overconsolidated kaolin clay adjacent to three different footprint types. The three footprint types -spudcan generated, a similarly shaped vertical walled auger generated, and shallow slope -were used to analyze separately the effect of shape and soil disturbance
Denial at the top table: status attributions and implications for marketing
Senior marketing management is seldom represented on the Board of Directors nowadays, reflecting a deteriorating status of the marketing profession. We examine some of the key reasons for marketingâs demise, and discuss how the status of marketing may be restored by demonstrating the value of marketing to the business community. We attribute marketingâs demise to several related key factors: narrow typecasting, marginalisation and limited involvement in product development, questionable marketing curricula, insensitivity toward environmental change, questionable professional standards and roles, and marketingâs apparent lack of accountability to CEOs. Each of these leads to failure to communicate, create, or deliver value within marketing. We argue that a continued inability to deal with marketingâs crisis of representation will further erode the status of the discipline both academically and professionally
Chemical Inhibition of the Mitochondrial Division Dynamin Reveals Its Role in Bax/Bak-Dependent Mitochondrial Outer Membrane Permeabilization
SummaryMitochondrial fusion and division play important roles in the regulation of apoptosis. Mitochondrial fusion proteins attenuate apoptosis by inhibiting release of cytochrome c from mitochondria, in part by controlling cristae structures. Mitochondrial division promotes apoptosis by an unknown mechanism. We addressed how division proteins regulate apoptosis using inhibitors of mitochondrial division identified in a chemical screen. The most efficacious inhibitor, mdivi-1 (for mitochondrial division inhibitor) attenuates mitochondrial division in yeast and mammalian cells by selectively inhibiting the mitochondrial division dynamin. In cells, mdivi-1 retards apoptosis by inhibiting mitochondrial outer membrane permeabilization. In vitro, mdivi-1 potently blocks Bid-activated Bax/Bak-dependent cytochrome c release from mitochondria. These data indicate the mitochondrial division dynamin directly regulates mitochondrial outer membrane permeabilization independent of Drp1-mediated division. Our findings raise the interesting possibility that mdivi-1 represents a class of therapeutics for stroke, myocardial infarction, and neurodegenerative diseases
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 molâ1. 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 ÎŒmol molâ1 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
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