Estimation of cooling rates during close-coupled gas atomization using secondary dendrite arm spacing measurement

Al-4 wt pct Cu alloy has been gas atomized using a commercial close-coupled gas-atomization system. The resulting metal powders have been sieved into six size fractions, and the SDAS has been determined using electron microscopy. Cooling rates for the powders have been estimated using a range of published conversion factors for Al-Cu alloy, with reasonable agreement being found between sources. We find that cooling rates are very low relative to those often quoted for gas-atomized powders, of the order of 10 K s for sub-38 μm powders. We believe that a number of numerical studies of gas atomization have overestimated the cooling rate during solidification, probably as a consequence of overestimating the differential velocity between the gas and the particles. From the cooling rates measured in the current study, we estimate that such velocities are unlikely to exceed 20 m s

La Négation

Au-delà d’un recensement des divers marqueurs de la négation dans une perspective purement grammaticale, les communications dont nous reproduisons le texte ont cherché à définir la logique de la négation et à analyser l’effectuation de cette opération fondatrice par l’énonciateur. C’est dire que le colloque a fait coexister deux axes essentiels, les auteurs ayant pratiqué, en fonction de leur spécialité, macro-analyses et micro-analyses. Les travaux réunis dans le présent volume s’inscrivent donc dans le cadre d’une analyse textuelle qui suppose l’application au discours littéraire de concepts propres à certaines théories linguistiques et esthétiques

At the Ragged Edges of Time: The Legend of Tilak and the Normalization of Historical Narratives

No description supplie

Women's and Men's Work: The Production and Marketing of Fresh Food and Export Crops in Papua New Guinea

© 2019 Oceania Publications Fresh food markets have been a fixture of the social and economic landscape of urban and rural PNG since colonial times. They were often the first points of engagement with the market economy, especially for women, who as small-scale producers, sold surplus produce from their food gardens located on communally-owned land. Although local food markets have remained an important livelihood for women, the later adoption and expansion of perennial export cash crops like coffee and cocoa overshadowed food production for local markets as men dominated export crop production on land alienated from communal ownership for decades or permanently. New forms of social relations of production and more exclusive forms of land tenure emerged to accommodate export crop production that were very different from those governing the production and marketing of fresh food. Market values and a trend towards individualisation of production with less capacity to mobilise labour through reciprocal labour exchange networks have characterised export crop production. With the income benefits captured largely by men, women began redirecting their labour to fresh food production where they were able to exercise more control of production and income while still mobilising labour through indigenous labour exchange arrangements. Attempts by men to appropriate the income of women and sons’ labour in export cropping were greater during flush periods when income levels were high, and they were less likely to attempt to appropriate this income in low crop periods when incomes were lower. However, with the recent emergence of female entrepreneurers earning relatively large sums of money in large-scale, profit-driven vegetable production, the moral frameworks governing food production are coming to resemble those governing export crops, and making labour more difficult to mobilise. Despite women being key players in these changes, we argue there is an emerging risk that men will attempt to assert control over this income or move into vegetable production themselves and possibly marginalise women in the process