The performance of membrane humidifier (MH) and enthalpy wheel humidifier (EWH) for a large power proton exchange membrane fuel cell (PEMFC) system is compared using simulations and experiments. The MH model is based on one dimensional diffusion equation and the EWH model is based on the porous media surface diffusion equation. Simulation results agree well with experimental data. According to the results, the effect of intake air temperature has a lower effect on the MH performance than it does on the EWH performance while the air mass flow has a much higher effect on the MH performance than it does on the EWH performance. MH performs better than EWH at a low flow rate but worse at a high flow rate. Vapor transfer mechanism in the humidifiers is also studied.
At present paper, an ionic liquid (N-butyl pyridinium hexafluorophosphate, [BPy]PF6) that is liquid at room temperature and solid above 75°C was synthesized and the contents of ferulic acid (FA) at Angelica sinensis was determined after solid-liquid separation using [BPy]PF6 as the solid extractant by spectrophotometry. The results show that FA is extracted completely by [BPy]PF6 at pH 3.34 and [BPy]PF6 at FA can be stripped by 0.02 mol/L NaOH. The content of FA in commercially available Angelicae sinensis was 0.057%. The working curve, linear range, detection limit and recovery rate of FA were Y = 0.0732X + 0.054 (R 2 = 0.9995), 5.150×10 -3 -3.508 mmol/L, 2.870×10 -4 mmol/L and 90.5-109.5%, respectively.
The Ba and Ag co-doped BaxAgyCa2.8Co4O9 thermoelectric bulk materials are fabricated by acid sol-gel and spark plasma sintering method. The phase compositions, microstructures and thermal transport properties of the resulting bulk materials are analyzed by X-ray diffraction, scanning electron microscopy and the thermal transport constant measurement apparatus. The results show that the thermal conduction behavior for the titled system can be effectively tuned by Ba and Ag co-doping, and the thermal conductivity could be reduced by increasing the Ba doping content. The analysis results show that the total thermal conduction suppressing comes from the lattice thermal conduction confinement. The Ba0.1Ag0.1Ca2.8Co4O9 bulk material is found to have the lowest thermal conductivity with total thermal conductivity and lattice thermal conductivity reaching 1.43 W/mK and 1.10 W/mK at 973 K, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.