Available online xxxKeywords: Polymer electrolyte fuel cell Nafion degradation Modelling Computational fluid dynamics Local operating condition a b s t r a c t The paper describes a development of a degradation model, which enables to predict timedependent changes in performance of a polymer electrolyte fuel cell. The developed model consists of two main parts: 1) a new semi-empirical model taking into account changes in physico-chemical properties of a polymer electrolyte membrane operating in the fuel cell, 2) a validated CFD model computing the 3D performance of the cell. In the semi-empirical model, the degradation rates of the membrane thickness and conductivity depend on the oxygen crossover rate. The acid group concentration is calculated from the membrane conductivity based on the percolation theory approach. The gas diffusion coefficients are modelled empirically as a function of the membrane thickness. The model of the membrane degradation is coupled with the CFD model and applied to analyse the cell behaviour as a function of time. The simulation shows that the cell current density decreases faster with lowering relative humidity and increasing temperature. The in-plane degradation of the membrane is non-uniform and depends on the local operating condition.
With the introduction of Google Cardboard, a combination of mobile devices, Virtual Reality (VR) and making was created. This “marriage” opened a wide range of possible, cheap Virtual Reality applications, which can be created and used by everyone. In this chapter, the potential of combining making, gaming and education is demonstrated by evaluating an implemented math-game prototype in a school by pupils aged 12-13. The aim of the virtual reality game is to solve math exercises with increasing difficulty. The pupils were motivated and excited by immerging into the virtual world of the game to solve exercises and advance in the game. The results of the evaluation were very positive and showed the high motivational potential of combining making and game-based learning and its usage in schools as educational instrument.
With the introduction of Google Cardboard, a combination of mobile devices, Virtual Reality (VR) and making was created. This “marriage” opened a wide range of possible, cheap Virtual Reality applications, which can be created and used by everyone. In this chapter, the potential of combining making, gaming and education is demonstrated by evaluating an implemented math-game prototype in a school by pupils aged 12-13. The aim of the virtual reality game is to solve math exercises with increasing difficulty. The pupils were motivated and excited by immerging into the virtual world of the game to solve exercises and advance in the game. The results of the evaluation were very positive and showed the high motivational potential of combining making and game-based learning and its usage in schools as educational instrument.
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.