Nickel-Based Anodes for Single-Chamber Solid Oxide Fuel Cells: A Catalytic Study
Single-chamber solid oxide fuel cells (SOFCs) are an alternative concept to traditional SOFCs. Conventional anodes, which consist of a cermet of metallic Ni and an ionic conductor, have to work under a mixture of hydrocarbon and oxygen. This paper presents a catalytic study of C 3 H 8 oxidation by Ce 0.9 Gd 0.1 O 1.95 and nickel. The influences of temperature and oxygen to propane ratio on the nickel oxidation state are clarified, thanks to catalytic tests and electrical conductivity measurements. The results show that the temperature must be higher than a critical value to maintain the nickel particles in the metallic state. Furthermore, at high temperatures, the conversion of the initial mixture leads to the water-gas-shift equilibrium.
High power-density single-chamber fuel cells operated on methane
Single-chamber solid oxide fuel cells (SC-SOFCs) incorporating thin-film Sm_(0.15)Ce_(0.85)O_(1.925) (SDC) as the electrolyte, thick Ni + SDC as the (supporting) anode and SDC + BSCF (Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)) as the cathode were operated in a mixture of methane, oxygen and helium at furnace temperatures of 500–650 °C. Because of the exothermic nature of the oxidation reactions that occur at the anode, the cell temperature was as much as 150 °C greater than the furnace temperature. Overall, the open circuit voltage was only slightly sensitive to temperature and gas composition, varying from ∼0.70 to ∼0.78 V over the range of conditions explored. In contrast, the power density strongly increased with temperature and broadly peaked at a methane to oxygen ratio of ∼1:1. At a furnace temperature of 650 °C (cell temperature ∼790 °C), a peak power density of 760 mW cm^(−2) was attained using a mixed gas with methane, oxygen and helium flow rates of 87, 80 and 320 mL min^(−1) [STP], respectively. This level of power output is the highest reported in the literature for single chamber fuel cells and reflects the exceptionally high activity of the BSCF cathode for oxygen electro-reduction and its low activity for methane oxidation.
Health services utilization in adult acquired major upper-limb amputees: a population-based survey.
OBJECTIVE
To increase knowledge of health services utilization and related factors in adult acquired major upper-limb amputees.


DESIGN
Population-based cross-sectional study conducted in Norway.


SUBJECTS
Two hundred and twenty four adult acquired major upper-limb amputees (57.4% response rate). Mean age was 53.7 years, 83.5% were men and mean post-amputation time was 24.0 years.


METHODS
Data were collected by postal questionnaires. Amputation-related health services utilization, perceived benefit and unmet needs were reported and associations between these factors and background factors were estimated by multivariate logistic regression analyses.


RESULTS
Reported health services utilization was relatively low. The reported benefit of utilized services was generally high. For several non-utilized services, considerable unmet needs for utilization were reported. Several background factors were significantly associated with different aspects of the services examined. A considerable discrepancy between reported pain and utilization of specified pain treatments was noted.


CONCLUSION
The findings of this study suggest that several health services available to acquired major upper-limb amputees should be strengthened. Establishing routines to ensure access to optimal, individualized rehabilitation may prevent disability. We recommend additional, longitudinal studies to further assess the need for mental health care and pain treatment in acquired major upper-limb amputees.