Heterogeneous conductivity parameters in a one dimensional fuel cell model

A model of one dimensional fuel cells is investigated, where the material inhomogeneities in the cathode are taken into account. We use the results in some preceding studies to describe the dynamics of the chemical reactions and transport of ions. A corresponding governing equation is derived for the numerical simulations. We apply an explicit-implicit time integration and Richardson extrapolation technique to increase the accuracy of the approximations. The efficiency of the method is demonstrated using a non-trivial test problem with real parameters. Numerical simulations are executed in presence of inhomogeneous conductivities and their effect on the cell potential is investigated

Understanding Program Slices

Program slicing is a useful analysis for aiding different software engineering activities. In the past decades, various notions of program slices have been evolved as well as a number of methods to compute them. By now program slicing has numerous applications in software maintenance, program comprehension, reverse engineering, program integration, and software testing. Usability of program slicing for real world programs depends on many factors such as precision, speed, and scalability, which have already been addressed in the literature. However, only a little attention has been brought to the practical demand: when the slices are large or difficult to understand, which often occur in the case of larger programs, how to give an explanation for the user why a particular element has been included in the resulting slice. This paper describes a reasoning method about elements of static program slices

Neutral Inhomogeneity in Circular Cylinder Subjected to Axial Load on its Lateral Boundary

In this paper we consider the problem of single circular elastic inhomogeneity embedded within a circular cylinder whose curved boundary surface is subjected to surface traction acting on axial direction. We investigate the displacement neutrality of the coupled system of host body and inclusion. Neutral inhomogeneity (inclusion) does not disturb the displacement, strain and stress fields in the host body. The deformation of the considered inhomogenneous cylinder is antiplane shear deformation

Koromkibocsátás vizsgálata pirolízisolaj-diesel tüzelőanyagkeverék alkalmazásánál: Investigation of soot emissions using pyrolysis oil-diesel fuel mixture

In modern days the waste generation of the modern society took such a large extent, that other than its environment harming aspects, it also endagers humanitiy’s sustainable development. Due to the motorisation and the increasing number of vehicles, the amount of used car tires is drastically increasing year by year. An estimated 1.5 trillion waste car tyres are generated annualy, which will be doubled in the following 30 years. One of the recycling methods of waste tires is pyrolysis, during which pyrolysis oil is produced. The components of said diesel fuel is different from the commercically avalible diesel fuel and the following research’s goal is to investigate the effects of pyrolysis diesel on the combustion, if we mix it in smaller volume percentages with regular diesel fuel. Kivonat A hulladéktermelés napjainkra a modern fogyasztói társadalom hatására olyan méreteket kezd ölteni, ami környezetkárosító hatása mellett veszélyezteti az emberiség fenntartható fejlődését. A motorizáció, a gépjárművek évről évre emelkedő száma miatt az elhasznált gumiabroncsok száma is drasztikusan emelkedik napjainkra körülbelül 1,5 billió elhasznált gumiabroncs keletkezik évente, ami a következő 30 évben előreláthatólag meg fog duplázódni [1]. A gumiabroncsok újra hasznosításának egyik módja a pirolizációs eljárás, amely során pirolízis olaj keletkezik [2]. Az ilyen eljárással nyert tüzelőanyag összetétele különbözik a kereskedelmi forgalomban kapható dieselolajtól, ezért a kutatás célja annak a vizsgálata, hogy milyen hatással van az égésre, ha kis térfogatszázalékban keverjük a diesel olajhoz. &nbsp

Exploiting Hierarchy in the Abstraction-Based Verification of Statecharts Using SMT Solvers

Statecharts are frequently used as a modeling formalism in the design of state-based systems. Formal verification techniques are also often applied to prove certain properties about the behavior of the system. One of the most efficient techniques for formal verification is Counterexample-Guided Abstraction Refinement (CEGAR), which reduces the complexity of systems by automatically building and refining abstractions. In our paper we present a novel adaptation of the CEGAR approach to hierarchical statechart models. First we introduce an encoding of the statechart to logical formulas that preserves information about the state hierarchy. Based on this encoding we propose abstraction and refinement techniques that utilize the hierarchical structure of statecharts and also handle variables in the model. The encoding allows us to use SMT solvers for the systematic exploration and verification of the abstract model, including also bounded model checking. We demonstrate the applicability and efficiency of our abstraction techniques with measurements on an industry-motivated example.Comment: In Proceedings FESCA 2017, arXiv:1703.0659