131 research outputs found
A Novel Accelerated Stress Test for a Representative Enhancement of Cathode Degradation in Direct Methanol Fuel Cells
No full textPerformance decay of direct methanol fuel cells hinders technology competitiveness. The cathode electrochemical surface area loss is known to be a major reason for performance loss and it is mainly affected by cathode potential and dynamics, locally influenced by water and methanol crossover. To mitigate such phenomenon, novel materials and components need to be developed and intensively tested in relevant operating conditions. Thus, the development of representative accelerated stress tests is crucial to reduce the necessary testing time to assess material stability. In the literature, the most diffused accelerated stress tests commonly enhance a specific degradation mechanism, each resulting in limited representativeness of the complex combination and interaction of mechanisms involved during real-life operation. This work proposes a novel accelerated stress test procedure permitting a quantifiable and predictable acceleration of cathode degradation, with the goal of being representative of the real device operation. The results obtained with a 200 h accelerated stress test are validated by comparing both in situ and post mortem measurements with those performed during a 1100 h operational test, demonstrating an acceleration factor equal to 6.25x and confirming the development of consistent cathode degradation
Modeling early requirements in Tropos: a transformation based approach
No full textWe are developing an agent-oriented software development technology, called Tropos, which integrates ideas from multi-agent system technologies and Requirements Engineering research. A distinguishing feature of Tropos is that it covers software development from early requirements analysis to detailed design, allowing for a deeper understanding of the operational environment of the new software system. This paper proposes a characterization of the process of early requirements analysis, defined in terms of transformation applications. Different categories of transformations are presented and illustrated by means of a running example. These transformations are then mapped onto a set of primitive transformations. The paper concludes with observations on the form and the role of the proposed transformation
Flooding of the diffusion layer in a polymer electrolyte fuel cell: Experimental and modelling analysis
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Water transport into PEFC gas diffusion layer: experimental characterization of diffusion and permeation
No full textEffect of anode MPL on water and methanol transport in DMFC: Experimental and modeling analyses
No full textTropos: An Agent-Oriented Software Development Methodology
No full textOur goal in this paper is to introduce and motivate a methodology, called for building agent oriented software systems. Tropos is based on two key ideas. First, the notion of agent and all related mentalistic notions (for instance goals and plans) are used in all phases of software development, from early analysis down to the actual implementation. Second, Tropos covers also the very early phases of requirements analysis, thus allowing for a deeper understanding of the environment where the software must operate, and of the kind of interactions that should occur between software and human agents. The methodology is illustrated with the help of a case study. The Tropos language for conceptual modeling is formalized in a metamodel described with a set of UML class diagram
Effects of anode MPL on DMFC mass transport phenomena and electrochemical impedance spectroscopy: experimental and modeling analyses
No full textA Knowledge Level Software Engineering Methodology for Agent Oriented Software
No full textOur goal in this paper is to introduce and motivate a methodology, called Tropos, for building agent oriented software systems. Tropos is based on two key ideas. First, the notion of agent and all the related mentalistic notions (for instance: beliefs, goals, actions and plans) are used in all phases of software development, from the early analysis down to the actual implementation. Second, Tropos covers also the very early phases of requirements analysis, thus allowing for a deeper understanding of the environment where the software must operate, and of the kind of interactions that should occur between software and human agents. The methodology is illustrated with the help of a case stud
Towards an Agent Oriented approach to Software Engineering
No full textAgent-oriented software development is gaining popularity over traditional software development techniques, including structured and object-oriented ones oriented software engineering. Several approaches have been proposed, ranging from informal methodologies, to formal ones, most of them focusing basically on architectural design. We are defining a software development methodology, called Tropos, which will allow us to exploit all the flexibility provided by agent oriented programming. The two novel features of Tropos are: first, that of using the notion of agent and all the related mentalistic notions in all phases of software development, from the early analysis down to the actual implementation; second, that of covering also the very early phases of requirements analysis, thus allowing for a deeper understanding of the environment where the software must operate, and of the kind of interactions that should occur between software and human agent
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