The Mechanical Properties of Palladium 20 a/o Silicon Alloy Quenched from the Liquid State

The elastic and plastic properties of filaments of non-crystalline Pd 20 a/o Si alloy and the changes that occur on crystallization during and after heating at various temperatures have been examined. The transformation to the crystalline states was examined with X-ray and electron diffraction, electrical resistivity and electron microscopy. The mechanical tests were performed over a temperature range between -195 and 500℃ through a range of strain rates from 10^ to 10^ sec.^ The non-crystalline structure was stable below 275℃ but transformed on heating at 300℃ or above to a face centered cubic structure (a_o=4.00-4.05 A), then to an unknown structure and finally to the stable orthorhombic Pd_3Si. The relatively high strength and brittle behavior of the non-crystalline form changed to lower strength but with more ductility on transforming to the metast-able crystalline states. The temperature dependence of the mechanical properties of both the non-crystalline and crystalline states was measured

Carbonodraco lundi gen et sp. Nov., the oldest parareptile, from Linton, Ohio, and new insights into the early radiation of reptiles

Redescription of the holotype specimen of Cephalerpeton ventriarmatum Moodie, 1912, from the Middle Pennsylvanian (Moscovian) Francis Creek Shale of Mazon Creek, Illinois, confirms that it is a basal eureptile with close postcranial similarities to other protorothyridids, such as Anthracodromeus and Paleothyris. The skull is long and lightly built, with large orbits and a dorsoventrally short mandible similar to most basal eureptiles. Two specimens referred previously to Cephalerpeton cf. C. ventriarmatum from the approximately coeval Linton, Ohio, locality differ significantly from the holotype in cranial and mandibular proportions and tooth morphology. This material and an additional Linton specimen compare favourably to ‘short-faced’ parareptiles, such as Colobomycter and Acleistorhinus, and justify recognition of an acleistorhinid parareptile in the Linton assemblage. The new binomen is thus the oldest known parareptile

Comparative Skull Morphology of Uropeltid Snakes (Alethinophidia: Uropeltidae) with Special Reference to Disarticulated Elements and Variation

Uropeltids form a diverse clade of highly derived, fossorial snakes that, because of their phylogenetic position among other alethinophidian lineages, may play a key role in understanding the early evolution of cranial morphology in snakes. We include detailed osteological descriptions of crania and mandibles for eight uropeltid species from three nominal genera (Uropeltis, Rhinophis, and Brachyophidium) and emphasize disarticulated elements and the impact of intraspecific variation on previously proposed morphological characters used for phylogenetic analysis. Preliminary analysis of phylogenetic relationships strongly supports a clade composed exclusively of species of Plectrurus, Uropeltis, and Rhinophis. However, monophyly of each of those genera and Melanophidium is not upheld. There is moderate support that Sri Lankan species (e.g., Rhinophis and Uropeltis melanogaster) are monophyletic with respect to Indian uropeltids. Previously proposed characters that are phylogenetically informative include the shape of the nasals, length of the occipital condyle, level of development of the posteroventral process of the dentary, and participation of the parietal in the optic foramen. Additionally, thirty new features that may be systematically informative are identified and described, but were not verified for their utility. Such verification must await availability of additional disarticulated cranial material from a larger sample of taxa. All characters require further testing through increased focus on sources and patterns of intraspecific variation, inclusion of broader taxonomic samples in comparative studies, and exploration of skeletal development, sexual dimorphism, and biogeographic patterns. Additionally, trends in the relative enlargement of the sensory capsules, reduction in cranial ossification and dentition, fusion of elements, and the appearance of novel morphological conditions, such as the structure and location of the suspensorium, may be related to fossoriality and miniaturization in some uropeltid taxa, and may complicate analysis of relationships within Uropeltidae and among alethinophidian snakes

Structural Stability and Mechanical Properties of Amorphous Metals

This is a review of the new information concerned with the structural stability and mechanical properties obtained, for the most part, by research groups at the Tohoku University. The contents consist of eight subjects ; 1) atomic structure, 2) effect of temperature on structure, 3) effect of deformation on structure, 4) elastic and anelastic behavior, 5) static strength, 6) deformation, 7) fracture, 8) ductility and toughness, and 9) fatigue properties. From these discussions, it will be concluded that amorphous metals represent a most intriguing group of materials and with further work a new family of materials become available for commercial applications