Anode-supported planar solid oxide fuel cells (SOFC) were fabricated by a single step co-firing process. The cells were composed of a Ni + yittria-stabilized zirconia (YSZ) anode, a YSZ electrolyte, an industrial Ca-doped LaMnO3 (LCM) (or lab-made LCM) + YSZ cathode active layer, and an industrial LCM (or lab-made LCM) cathode current collector layer. The fabrication processes involved tape casting of the anode, screen printing of the electrolyte and the cathode, and one step co-firing of the green-state cells at 1300°C for 2h . The performance of the cells was greatly improved by optimization of these materials and fabrication processes. The electrochemical performance tests of these cells showed that they could provide a stable power density of 0.2– 1.0W∕cm2 with hydrogen as fuel and air as oxidant while operating in the temperature range 700– 900°C . The effects of various polarization losses including ohmic polarization, activation polarization, and concentration polarization were studied by impedance spectroscopy measurements and curve-fitting experimentally measured voltage vs current density traces into an appropriate model. Based on these measurements and curve fitting results, the relationships between cell performance and various polarization losses and their dependence on temperature and microstructure, were rationalized.

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Memory loss is the key symptom of Alzheimer's disease (AD). As successful drug treatments have not yet been identified, non-pharmaceutical interventions such as physical exercise and training have been employed to improve the memory function of people with dementia. We investigated the effect of prolonged physical running on hippocampal-dependent spatial memory and its underlying mechanisms using a well-established rodent model of AD. 3xTg-AD transgenic mice and non-transgenic mice were subjected to voluntary wheel running for 5 months (1 hour per day, 5 days per week), followed by spatial memory testing. After the behavioral testing, dendritic spines, synapses, and synaptic proteins as well as amyloid-beta (Aβ) pathology were analyzed in the dorsal hippocampi. Running improved hippocampal-dependent spatial memory in 3xTg-AD mice. This running strategy prevented both thin and mushroom-type spines on CA1 pyramidal cells in 3xTg-AD mice, whereas the effects of running in non-transgenic mice were limited to thin spines. The enormous effects of running on spines were accompanied by an increased number of synapses and upregulated expression of synaptic proteins. Notably, running downregulated the processing of amyloid precursor protein, decreasing intracellular APP expression and extracellular Aβ accumulation, and spatial memory performance correlated with levels of Aβ peptides Aβ 1-40 and Aβ 1-42 . These data suggest that prolonged running may improve memory in preclinical AD via slowing down the amyloid pathology and preventing the loss of synaptic contacts.

The anode-supported planar solid oxide fuel cell (SOFC) was fabricated by a cost-effective single step cofiring process using high shear compaction (HSC)™ anode substrate. The HSC™ process is a novel ceramic tape fabrication technique, which offers advantages in low-cost and high-volume production of the anode substrates over the conventional tape forming processes. The cell was comprised of a porous HSC™ Ni+8 mol % yttria-stabilized zirconia (YSZ) anode substrate, a porous Ni+YSZ anode barrier layer, a porous and fine-grained Ni+YSZ anode active layer, a dense YSZ electrolyte, a porous and fine-grained Ca-doped LaMnO3(LCM)+YSZ composite cathode active layer, and a porous LCM cathode current collector layer. The fabrication process involved wet powder spraying of the anode barrier layer over the HSC™ anode substrate followed by screen-printing of the remaining component layers. The cell was then cofired at 1340°C for 2 h. The microstructure and the open circuit voltage of the cell confirmed that the cell was crack-free and leak-tight. The cofired cell showed a stable and acceptable electrochemical performance at 800°C under humidified hydrogen (3–60% H2O) as fuel and air as oxidant. The anode active layer with finer and less porous microstructure increased the triple phase boundary length and improved cell performance under conditions that simulated higher fuel utilization. The material system and fabrication process presented in this work offers great advantage in low-cost and high-volume production of SOFCs, and it can be the basis for scale-up and successful commercialization of the SOFC technology.

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In order to understand the microstructural evolution in plasma sprayed coatings, the solidification process was modeled using a 2-D FEM model based on enthalpy formation. Studies of the surface of the coatings showed surface roughnesses across multiple length scales. The model was used to examine the effects of the substrate and splat temperatures and the surface roughness features on the onset of remelting of the underlying surface on which the splat solidifies. The surface roughness was found to promote remelting, indicating that it was an important parameter that determines splat solidification. The temperatures of the splat and substrate were consolidated into one non-dimensional parameter that captured the onset of remelting with a non-dimensional remelting point.A fully coupled thermo-mechanical finite element model was also run for a single splat case, to provide more insight stress buildup during solidification. An important result was that the relative size of the surface roughness features, as compared to the splat thickness, is very important. Very large wavelengths compared to splat thickness lead to smaller stresses, since the solidification and the interface are essentially 1-D. Very small wavelengths compared to splat thickness also leads to reduced stresses, since the solidification front quickly becomes 1-D. Only roughness features on the scale of splat thickness are important in providing locations of maximum stress concentration, which are locations of microcrack formation.

A fully coupled thermo-mechanical finite element model was used to study the buildup of stresses during splat solidification, and to understand the effect of deposition conditions on crack formation during plasma spray deposition. Through the simulation, the locations and magnitudes of maximum stresses were identified, where crack formation would presumably initiate. The model showed that the stresses scaled with the temperature difference between the superheated splat and the substrate. The simulation further showed that the stresses scale with the three geometric parameters, and two independent geometric ratios were defined; ζ (defined as t/λ) and ψ (defined as A/λ). 2D maps of maximum S11 and S22 under different combinations of ζ and ψ were constructed. The mappings showed that only roughness features on the scale of splat thickness were important in providing locations of maximum stress concentration.