Search results

181 records were found.

The grain refinement potency of some recently reported grain refiners for Mg-Al based casting alloys, including TiC, TiN, SiC and TiB2, was investigated from a crystallographic viewpoint using the edge-to-edge matching model. The results show that TiB2 is more likely to form an energetically favourable orientation relationship with the Mg matrix, and it is predicted that TiB2 should have the best grain refinement efficiency. The other three compounds may also serve as heterogeneous nucleation sites, but are not likely to be as effective as TiB2. The present analysis provides a better rationale of the superior grain refinement performance of TiB2 compared with SiC.
Learning about the utilization, development and perhaps conservation of energy for our expanding world population has long been a part of science curricula. The world “about” is, however, paramount in describing the nature of these courses, and parallels a similar phenomenon observed in numerous so-called environmental education programmes in schools. Despite the close association between energy use expansion and environmental impact, little “energy education for the environment’ has occurred in this country. This paper examines some of the reasons for this situation and highlights the difficulties facing the environmental education teacher who wishes to lead a valid study of energy sources. External community influences, a lack of breath and problems with information availability are identified as factors which contribute to the...
Mexico, rural female migration, ejido, migrant networks,
Upward and downward IR flux expressions for nontransparent and semitransparent computational models applied to atmospheric measurements
Atmospheric diabatic heating and cooling assessed by Tiros III radiation measurements and conventional data
Want to know more?If you want to know more about this cutting edge product, or schedule a demonstration on your own organisation, please feel free to contact us or read the available documentation at http://www.keep.pt/produtos/retrievo/?lang=en