FUELCELL2008-65079 EFFECTS OF ELECTRODE MICROSTRUCTURE ON POLARIZATION CHARACTERISTICS OF SOFC ANODES

ABSTRACT Anode microstructure parameters were quantified by SEM-EDX measurements and the dependence of polarization characteristics on the anode microstructure parameters is investigated experimentally. Nickel yttria-stabilized zirconia (Ni-YSZ) anode supported cells with a thin YSZ electrolyte, lanthanum-strontium-manganite(LSM)-YSZ composite cathode, and LSM cathode current collector layers were fabricated by dip coating method. Anode microstructure was successfully imaged and quantified by ultra low voltage SEM and by means of stereology. Cell voltage measurements and impedance spectroscopy were performed at 650 and 750˚C with hydrogen diluted by nitrogen as a fuel. A quantitative relationship between measured polarization and microstructure parameters, e.g., three phase boundary length, contiguity, etc., was discussed. Finally, a cell with an anode functional layer (AFL) was fabricated to investigate the possibility of improving both activation and concentration polarization characteristics

Effect of additional magnesium on mechanical and high-cycle fatigue properties of 6061–T6 alloy

The effect of additional solute magnesium (Mg) on mechanical and high-cycle-fatigue properties of 6061-T6 aluminum alloy is investigated in detail. By adding 0.5% and 0.8% Mg to the 6061-T6 alloy with a normal stoichiometric Mg2Si composition (base alloy), the alloy exhibits eminent strain-aging characteristics demonstrated by the emergence of serrated flow, the negative strain-rate-sensitivity and relatively weakened temperature dependency of flow stress. The Mg-added new alloy also shows higher work-hardening rate than the base alloy particularly at initial flow regime and at lower strain rate. The S-N curve of the new alloy shows a clear fatigue limit which is absent in the base alloy. The fatigue limit of the new alloy is shown to be controlled by the threshold against small crack growth. Moreover, the new alloy clearly exhibits a coaxing phenomenon (time-dependent strengthening) which is absent in the base alloy. The coaxing effect is attributed to the existence of a small quasi-non-propagating crack whose growth resistance gradually increases during stress amplitude step-ups.This study was financially supported in part by the Kansai University Grant-in-Aid for progress ofresearch in graduate course (2012) and also by the Kansai University Expenditures for Support ofTraining Young Scholars (2013)

Modeling and Design of Micro Groove Falling Film Evaporators,” ICMM2004

ABSTRACT In the present study, heat transfer in a falling film micro groove evaporator has been simulated by an analytical model. The flow and thermal fields were divided in two regions, i.e. macroscopic flow inside the groove and the microscopic flow where intensive evaporation takes place at the thin film interline region. For the micro region model, pressure in the liquid film was expressed as a sum of surface tension and disjoining pressure effects. The film thickness profile was obtained by solving the 4th order differential equation by Runge-Kutta method. Then, this micro region model was combined with the macro region model. Macro region model solves one dimensional bulk flow inside the groove with gravitational effect taken into account. Constant curvature of the liquid vapor surface was assumed for the macro flow. It is shown that the gravitational force is essential for providing the liquid to wide range of heat transfer area. Thus, diverging branch evaporator is investigated. It is demonstrated that this concept has large potentiality for improving the performance of the micro groove falling film evaporator

Empagliflozin in Patients with Chronic Kidney Disease

Background The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. Methods We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m(2) of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m(2) with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to < 10 ml per minute per 1.73 m(2), a sustained decrease in eGFR of & GE;40% from baseline, or death from renal causes) or death from cardiovascular causes. Results A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P < 0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P=0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. Conclusions Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo