Molten aluminium attack on iron based alloys

Liquid aluminium alloys affect the moulds, by formation of intermetallic layers at their surface; such attack is enhanced by the flow of the molten metal on the surface of the tooling. Metal tooling are used to promote high heat transfer rates and increase the solidification rate to enhance mechanical properties in cast pieces, but the damage to their surface affects their quality and increases the production costs due to the need to repair them. This work presents the results of a series of studies conducted to evaluate the attack produced by molten aluminium on samples of iron based materials commonly used in the manufacture of dies and moulds. The studies were conducted in a machine that imposes a rotating movement to experimental specimens to simulate the flow of liquid metal. The damage observed in the samples was compared to that experienced by tooling in the melt shop.The authors thank the Mexican National Council for Science and Technology (CONACYT), Mexico, and CDTI (Centro de Desarrollo Tecnológico Industrial), Spain, and the Program for the Support of Scientific and Technological Research (PAICYT) of UANL, for the support of this project

Biogeography of New World Tarantulas

Biogeography is a multidisciplinary field that is concerned with delimit- ing and explaining the geographic distributions of organisms in space and time. Due to their distribution patterns and interesting biology (e.g., ancient lineage with a nearly cosmopolitan distribution, sedentary lifestyle with limited dispersal capabili- ties), tarantulas are an appealing taxonomic group for addressing a variety of bio- geographic questions concerning the Earth’s history. In this chapter, we discuss some biogeographic basic concepts, delve into the distribution patterns of New World tarantulas, and explore some of the historical explanations that may have led to these distributions. We mostly review and highlight the results of recent studies but also include personal observations and unpublished data. The distributions of higher-level taxonomic groups (subfamilies and tribes) are described and we detail their latitudinal and elevational limits. We also review the distributions of groups with unique insular habitats such as those found on islands surrounded by seas, forested “islands” surrounded by “seas” of deserts, and caves. Furthermore, we dis- cuss the distribution of some unique morphological characters of taxonomic impor- tance such as urticating setae. Finally, we review a handful of studies that have explicitly investigated the biogeography of New World tarantulas using a variety of different analytical methods.Fil: Perafán, Carlos. Universidad de la República. Facultad de Ciencias; UruguayFil: Ferretti, Nelson Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Hendrixson, Brent E.. Millsaps College. Department Of Biology; Estados Unido