The TONUS CFD code for hydrogen risk analysis: Physical models, numerical schemes and validation matrix

The French Atomic Energy Commission (CEA) and the Institute for Radiological Protection and Nuclear Safety (IRSN) are developing a hydrogen risk analysis code, called the TONUS code, which incorporates both lumped-parameter (LP) and computational fluid dynamics (CFD) formulations. In this paper we present the governing equations, numerical strategy and schemes used for the CFD approach.Several benchmark exercises based on experimental results obtained on large-scale facilities, such as MISTRA, TOSQAN and RUT, are presented. They have been used as verification and assessment procedures for modelling and numerical approaches of the code. Specific emphasis is given to the sensitivity analysis of the computed results with respect to numerical and physical parameters. The powerful Design-Of-Experiments technique for sensitivity analysis is successfully applied to the ISP47 MISTRA test case.The TONUS CFD code is presently used to support the hydrogen risk assessment for the European Pressurized Reactor (EPR) plant and to investigate the impact of the two-room concept on hydrogen distribution in the EPR containment.     

Vat dye sensitised fibre damage and dye fading by catalytic and activated peroxide bleaching

At equal levels of performance, activated (TAED) and catalytic (Mn-TMTACN) laundry bleaching can differ considerably in terms of the concomitant damage to fibres and dyes. To quantify this damage, differently dyed cotton fabrics, and a representative set of eight vat dyes and CI Reactive Brown 7 were used. It is shown that dye fading and fibre degradation are dye-specific and are both highly coupled phenomena. The interpretation of the damage data is based on dye chemistry, reflectance spectroscopy (UV/VIS and NIR) and EPR measurements. Whereas compelling evidence for a genuine catalytic cycle with the quoted manganese complex is lacking, a possible catalytic role of the dyes is proposed. The dramatic green shift resulting from the catalytic bleaching of Cl Vat Blue 4 is explained in detail. The corresponding oxidation is reversible and possibly useful as a fibre damage indicator.     

Common knowledge does not have the Beth property

Common knowledge is an essential notion for coordination among agents. We show that the logic of common knowledge does not have the Beth property and thus it also lacks interpolation. The proof we present is a variant of Maksimova's proof that temporal logics with ‘the next’ do not have the Beth property. Our result also provides an explanation why it is so difficult to find ‘nice’ deductive systems for common knowledge.     

An environment for reusing ontologies within a knowledge engineering approach

Domain models can be constructed more easily and made more robust by reusing ontologies in a well-defined way. In this paper the KARO approach is introduced which provides various means of retrieving and adapting components of an ontology as part of a domain model construction process. KARO is based on the knowledge-processing component LILOG-KR provided by the LILOG text-understanding system. Above all, the notion of classification is applied for the retrieval of relevant categories. The upper structure of LILOG-KB serves as an exemplary ontology. By integrating KARO into the Model-based and Incremental Knowledge Engineering Environment (MIKE) the reuse of a predefined ontology can be integrated into the development process of expert systems in a systematic way.     

Fixed mobile internet convergence (FMIC)

Convergence is one of the most frequently used catchwords in the information and communication field. While in general the increasing growing together of telecommunication, information and media technology is understood by this term and much has already been written about it, the term FMIC has existed for only a short time yet in telecommunication, and has not yet appeared much in the literature. FMIC stands for fixed mobile internet convergence and means the growing together of fixed networks, mobile networks and the Internet. In this article it will be demonstrated by means of three top existing current services what one should expect from the so-called FMIC-services.     

Properties of large-scale methane/hydrogen jet fires

A future economy based on reduction of carbon-based fuels for power generation and transportation may consider hydrogen as possible energy carrier. Extensive and widespread use of hydrogen might require a pipeline network. The alternatives might be the use of the existing natural gas network or to design a dedicated network. Whatever the solution, mixing hydrogen with natural gas will modify the consequences of accidents, substantially. The French National Research Agency (ANR) funded project called HYDROMEL focuses on these critical questions. Within this project large-scale jet fires have been studied experimentally and numerically. The main characteristics of these flames including visible length, radiation fluxes and blowout have been assessed.     

Copper‐Catalyzed Enantioselective [2+2] Cycloadditions of 2‐Nitrosopyridine with Ketenes

Copper(I)‐catalyzed [2+2] cycloadditions of various ketenes with 2‐nitrosopyridine to afford synthetically highly valuable 1,2‐oxazetidine‐3‐ones are shown to occur with good enantioselectivities. The thermal uncatalyzed process furnishes the unstable regioisomeric oxazetidinone. Density function theory (DFT) calculations give evidence that the reaction occurs via a concerted [2+2] cycloaddtion pathway.     

Alkali-aggregate reaction in Swiss tunnels

Currently the work for two new railway tunnels through the Swiss Alps with a length of 35 and 57 km respectively is in progress. Prepared aggregates quarried from the tunnels are reused for the concrete. About 50% of these aggregates are classified as reactive in regard to alkali-aggregate reaction (AAR) according to the AFNOR P 18-588 microbar test. In order to obtain information about AAR in concrete exposed to underground conditions, eight existing tunnels are investigated in this study. The concrete and shotcrete of the 16 coring sites studied is between 19 and 44 years old. The visual inspection of the tunnels and the physical properties of the concrete and shorcrete indicate no substantial damage although signs for AAR are present in the majority of the samples. Furthermore, the aggregates of seven coring sites are classified as reactive, but they obviously do not reach their reaction potential. A possible reason might be the minor climatic fluctuations in the tunnels. The results of this study indicate that reactive aggregates might be used for concrete in tunnels without causing damage due to AAR.

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Résumé Actuellement deux nouveaux tunnels ferroviaires d'une longueur de respectivement 35 et 57 km, sont en cours de construction à travers les Alpes suisses. Les déblais de roches produits par leur percement sont traités et recyclés comme granulats pour la confection du béton utilisé dans ces tunnels. Selon les essais réalisés avec le test Microbar selon la norme AFNOR P 18-588, environ 50% de ces granulats sont à classer comme réactifs pour ce qui est de la réaction alcalis-granulats (RAG). Afin d'obtenir des informations sur la RAG dans le béton des tunnels, on a procédé à une étude sur huit tunnels existants. Le béton et le béton projeté des 16 carottages réalisés étaient agés de 19 à 44 ans. L'inspection visuelle des tunnels ainsi que la détermination des caractéristiques mécaniques des bétons n'ont révélé aucun dommage substantiel, cela bien que la majorité des éprouvettes examinées présentat des signes d'une RAG. Par ailleurs les granulats de sept de ces carottages sont à classer comme réactifs. Manifestement ces granulats n'ont pas pu développer totalement leur potentiel de réactivité. Une des causes possibles de ce comportement pourrait résider dans les faibles variations climatiques existant dans les tunnels. Les résultats de cette étude montrent qu'il est possible d'utiliser des granulats réactifs pour les bétons destinés à être mis en place dans les tunnels sans qu'il se produise de dommages par réaction alcalis-granulats.

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Editorial Note The Swiss Federal Laboratories for Materials Testing and Research (EMPA) is a RILEM Titular Member. Dr. Andreas Leemann participates in RILEM TC 188-CSC ‘Casting of self-compacting concrete’ and DSC ‘Durability of self-compacting concrete’. Mr. Werner Studer is a RILEM Senior Member.     

Canonical completeness of infinitary μ

This paper presents a new model construction for a natural cut-free infinitary version of the propositional modal μ-calculus. Based on that the completeness of and the related system K_ω(μ) can be established directly – no detour, for example through automata theory, is needed. As a side result we also obtain a finite, cut-free sound and complete system for the propositional modal μ-calculus.