Study of the microstructure resulting from brazed aluminium materials used in heat exchangers

Re-solidification of AA4343 cladding after brazing as well as the related precipitation in the modified AA3003 core material have been investigated. Analysis of the re-solidified material showed that partial dissolution of the core alloy occurs in both the brazing joints and away of them. Far from the brazing joints, the dissolution is, however, limited and diffusion of silicon from the liquid into the core material leads to solid-state precipitation in the so-called “band of dense precipitates” (BDP). On the contrary, the dissolution is enhanced in the brazing joint to such an extent that no BDP could be observed. The intermetallic phases present in the resolidified areas as well as in the core material have been analyzed and found to be mainly cubic alpha-Al(Mn,Fe)Si. These results were then compared to predictions made with available phase diagram information

Environmental change, displacement, and pro-longed conflict: Climate Security in Singhere and Bissine, Casamance: Field Report

also available in French Sarzana C, Krendelsberger A, Diallo O, Ndiaye BMT, Pacillo G, Laderach P. 2022. Changement environnemental, déplacement et conflit prolongé : Sécurité Climatique à Singhere et Bissine, Casamance. Rapport de terrain. CGIAR Focus Climate SecurityThis report recounts historical information gathered through interviews and focus group discussions in Singhere and Bissine regarding displacement, resource use and production, climate and environmental problems, while also providing future outlook highlights. In addition, it provides recommendations on context-specific climate adaptation intervention needs

Beef and dairy value chains in Senegal: Problems and Opportunities

Livestock production, especially pastoralism, is a vital part of the Senegalese economy. A large variety of production methods have been observed: from producing milk for household consumption, to collection and transformation by cooperatives to distribute the milk nationwide. The most significant problems faced are increased competition for fewer resources (namely pasture biomass and water) which, compounded with high feed prices and tight margins, contributes to conflict. There are opportunities to improve the marketability of dairy products and milk and beef productivity by improving connections to the market, testing different stabling and feed practices, adapting climate information services to producers’ needs, identifying and rehabilitating transhumance corridors, improving accessibility to feed, and introducing better and more veterinary checks

Assessing the relationship between climate, food security and conflict in Ethiopia and in the Central American Dry Corridor (CADC). Quantitative analysis on the impact of climate variability on conflict in Ethiopia and in the CADC countries

In this study, we investigate the climate-food security-conflict nexus in Ethiopia and the CADC (Guatemala, El Salvador, Nicaragua, Honduras). Both Ethiopia and the CADC are hotspots of high climate variabilities, high political insecurity, and conflicts and widespread food and nutrition insecurities across their populations. Therefore, the main research questions that this study aims to answer for the CADC countries: • Is climate exacerbating existing threats that could increase the risk of conflict in the CADC countries and in Ethiopia? • Are areas of high climate variability correlated to high socio-political insecurity in the CADC countries and in Ethiopia? • How can WFP programming become more climate security sensitive? Our main findings can be summarized as follows: (1) Climate exacerbates existing household level risks and insecurities that can increase the likelihood and intensity of conflict. In other words, we find evidence that climate is a threat multiplier in Ethiopia and El Salvador . (2) In addition to climate induced insecurities, there exist other important household level predictors of conflict, such as age, education, and gender of the head of the household, ethnicity, access to electricity and location in Ethiopia and El Salvador. (3) The climate security nexus – the way climate, socio-economic and political risks and insecurities are linked to each other – differs across countries (Guatemala, Honduras, Nicaragua, El Salvador and Ethiopia) and conflict clusters. (4) There exist “climate insecurity hotspots” at sub-national level where high level of climate variability, conflict intensity and diversity co-occur with other existing socio-economic insecurities

Morphological changes and segregation of β-Al9Fe2Si2 phase: A perspective from better recyclability of cast Al-Si alloys

High iron impurity has detrimental effects on the castability and tensile properties of recycled aluminium alloys. The present study reports the engineering of intermetallic β-phase present in hypoeutectic cast Al-Si model alloy systems with high Fe content (2 wt% Fe) in order to demonstrate the promising recyclability despite having high Fe content. Thermodynamic interplay between Si and Fe concentration on the formation of the β-phase and the solidification behaviour of the hypoeutectic Al-Si alloys has been explored. It has been demonstrated that with suitable heat treatment it is possible to alter the morphology of the β-phase and based on the experimental evidences, for the first time, the mechanism behind the solid-state morphological changes of beta phase has been proposed. Based on the experimental results and thermodynamic calculations it has been suggested that elimination of beta phase by gravitational segregation is more suitable for the near-eutectic 10 wt% Si alloy; whereas for 6 wt% Si alloy, morphological change of β-phase is recommended. It was also found that morphological change of beta-phase and Si could help recover the strength and ductility in the recycled Al-Si alloys having high Fe content.The aegis of Marie Sklodowska Curie Individual Fellowship (MSCA-IF-2015), European Commission (EU project no. 656943)

Der Verbalaspekt im Russischen und didaktische Ansichten

Diese Arbeit beschäftigt sich mit dem Thema „Verbalaspekt im Russischen und didaktischen Ansichten“. Dabei wurde versucht, empirisch die Schwierigkeiten bei der Anwendung des russischen Verbalaspekts in der Praxis herauszufinden und einschlägige Schlussfolgerungen sowohl für die Unterrichtspraxis als auch für Russischstudierende zu formulieren. Die daraus gewonnen Erkenntnisse könnten Russischunterrichtenden helfen didaktische Schwerpunkte bei der Vermittlung des russischen Verbalaspekts zu setzen. In dieser Diplomarbeit wird zuerst ein Überblick über die theoretischen Grundlagen im Bereich der semantisch - grammatischen Eigenschaften des Verbalaspekts gegeben. Danach werden Kenntnisse von Studierenden mit unterschiedlichem Sprachniveau anhand eines Fragebogens getestet. Anschließend werden die Ergebnisse dieser Untersuchung ausgewertet und analysiert. Bezüglich didaktischer Ansichten wurden folgende Einzelfunktionen des Aspekts bei den Studierenden nach dem Prinzip der Gegenüberstellung abgefragt: a) abgeschlossene vs. nicht-abgeschlossene Handlung; b) nacheinander ablaufende Handlung vs. gleichzeitig ablaufende Handlung; c) einmalige Handlung (Episode) vs. nicht einmalige Handlung; d) konkret-faktische Bedeutung vs. verallgemeinert-faktische (abstrakte) Bedeutung. Die ersten drei Bedeutungen des Aspekts schienen den Studierenden vertraut zu sein. Bei der vierten Gegenüberstellung war das nicht der Fall, speziell in der Aufgabe bezüglich der russischen Zukunftsform. Die Auswertung der Ergebnisse hat gezeigt, dass die Befragten mit nichtrussischer Muttersprache (überwiegend Deutsch) erhebliche Schwierigkeiten bei der Anwendung des russischen Verbalaspekts haben. Die empirische Forschung erwies sich als nützliches und wichtiges Werkzeug für die mögliche Steuerung von Lernprozessen. Die Ergebnisse haben das Potenzial das Sprachniveau der Lernenden zu verstehen und gezielt anzusprechen

Three decades after being displaced by conflict, Senegalese communities return to find the climate changed things, too

A blog summarizing preliminary insights on climate security risks in Casamance gathered through field work activitie