Pratiquer le refus implique une mentalité guérillera

Depuis le dernier congrès des délégués deux événements politiques majeurs ont polarisé de façon dichotomique l’activité politique au sein de l’union : la formation de la Grande Coalition et l’assassinat politique du 2 juin à Berlin. Ainsi, pour la première fois depuis la scission du SPD, la question de l’organisation s’est posée au sein de l’Union comme une question d’actualité politique. Le fait d’attribuer une importance majeure à l’un plutôt qu’à l’autre de ces deux événements a tendanciel..

Visualization of cavitation and investigation of cavitation erosion in a valve

Avoiding cavitation and especially cavitation erosion are tasks, which have to be considered when working with hydraulics. State of the art is the assessment of the risk of erosion by component testing or to completely avoid cavitation by means of CFD. Another reliable method to assess the risk of cavitation erosion is until now not available. This paper deals with this problem and delivers comparative values for a later method development. In a first step the cavitation of a poppet valve, which controls a methanol flow, is visualized. The resulting three cavitation appearances are deeply examined. After that the results of long-term tests at different operation conditions are presented. A poppet surface analysis following each experiment has shown different types of surface attacks. As a result of this work it is shown that both cavitation appearance and surface attack are strongly influenced by the temperature dependent air solubility of the liquid

Alcohols as a Means to Inhibit the Formation of Precipitates in Blends of Biodiesel and Fossil Diesel Fuel

The European diesel fuel specification limits the biodiesel content to 7 %. It is, however, desirable to increase the amount of renewables in the transport sector; therefore blending with a higher biogenic fuel content is of interest. Blending of fuels can lead to chemical reactions between fuel components and may result in undesired products. In detail, aged biodiesel from unsaturated FAME and fossil diesel fuels can form oligomers and precipitations with a maximum in the range of B10 to B20. Precursors are oligomers that can be separated from the biodiesel or the blends in an amount of up to 20 %. These oligomers seem to have potency for chemical reactions with fuel components or the engine oil. To prevent tentative problems in the fuel filter, the injecting system and the combustion process itself, the formation of oligomers should be disabled in blends. Alcohols have been proven and tested to dis-solve precipitations in the fuel. However, flash point problems occur, in case the alcohols have too low boiling points. In our tests, some alcohols could be identified to reach the demands of the diesel fuel standard EN 590. As acceptable monovalent alcohols, the longer-chained alcohols 1-octanol, 3-methyl-1-butanol (isoamyl alcohol) and 2-hexyldecan-1-ol were found. The blends with these alcohols both showed acceptable flashpoints according to DIN EN 590 and could prevent the occurrence of precipi-tates when added in a rather low concentration of about 6 to 8 %. Additionally, engine tests were carried out to monitor regulated and non-regulated emissions. The emissions of selected blends (B10+6OctOH, B10+8IsoamylOH, B10+8HexdecOH) were analyzed by using a single cylinder test engine (Farymann Diesel 18W, TIER 4, agricultural 5-mode test). All of these blends showed less NOx emissions than the pure B10 blend without addition of alcohol. For the CO, HC and PM emissions, no remarkable changes could be found. In the case of non-regulated emis-sions, no relevant changes were observed in carbonyl and PAH emissions, relative to the B10 blend without addition of alcohol. In the result, some blends from biodiesel, diesel fuel and alcohols tend to be appropriate to suppress chemical reactions in the fuel and probably in the engine oil. Further research is necessary to explain the chemical interactions that are responsible for the formation of oligomers and their reaction products. Not only chemical but physical bonds can play important roles and are in the focus of current research

LIFE-SHARE Project: Developing a Digitisation Strategy Toolkit

This poster will outline the Digitisation Strategy Toolkit created as part of the LIFE-SHARE project. The toolkit is based on the lifecycle model created by the LIFE project and explores the creation, acquisition, ingest, preservation (bit-stream and content) and access requirements for a digitisation strategy. This covers the policies and infrastructure required in libraries to establish successful practices. The toolkit also provides both internal and external resources to support the service. This poster will illustrate how the toolkit works effectively to support digitisation with examples from three case studies at the Universities of Leeds, Sheffield and York

Negotiation versus mediation in international conflict: Deciding how to manage violent conflicts

The thesis is an attempt to fill the theoretical and empirical gap in current conflict management research, which has failed to examine methods of conflict management comparatively. Two dominant paradigms exist, neither of which is adequate to the task of comparing negotiation and mediation in the real world of international politics: the Psychology paradigm and the Third Party Intervention paradigm. An alternative theoretical framework, the Contingency framework of negotiation and mediation was therefore, constructed. This model suggests that negotiation and mediation are conceptually and empirically different, and specifies a series of contextual and process variables which are vital to any examination of conflict management. Utilising a unique data set of thousands of cases of negotiation and mediation coded according to the variables specified in the Contingency model, a general bivariate analysis, followed by a more in-depth multivariate analysis, revealed a number of important differences and similarities between the two methods. The results suggest that negotiation and mediation are different forms of conflict management, which are most likely to be successful under contrasting conditions in international politics. Negotiation is the most successful method overall, but tends to be limited to low intensity, interstate conflicts. Mediation tends to occur in the most intense, intractable, and primarily civil conflicts, and is useful under a number of onerous circumstances

Visualization of cavitation and investigation of cavitation erosion in a valve

Avoiding cavitation and especially cavitation erosion are tasks, which have to be considered when working with hydraulics. State of the art is the assessment of the risk of erosion by component testing or to completely avoid cavitation by means of CFD. Another reliable method to assess the risk of cavitation erosion is until now not available. This paper deals with this problem and delivers comparative values for a later method development. In a first step the cavitation of a poppet valve, which controls a methanol flow, is visualized. The resulting three cavitation appearances are deeply examined. After that the results of long-term tests at different operation conditions are presented. A poppet surface analysis following each experiment has shown different types of surface attacks. As a result of this work it is shown that both cavitation appearance and surface attack are strongly influenced by the temperature dependent air solubility of the liquid