Home About us Contact
|
Home About us Contact | ||
|
|
||
Composition Leading (composition + leading)
Selected AbstractsEcomorphometric variation and sexual dimorphism in the common shrew (Sorex araneus)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2009T. A. WHITE Abstract We investigated the evolution of the biomechanics of the mandible in island and mainland populations of the common shrew on the west coast of Scotland. We predicted that climatic differences between populations should cause differences in prey composition leading to changes in the mechanical potential (MP) of the mandible. In females, MP was correlated with climate, with greater MP in warmer and drier habitats. In males, MP was significantly greater than in females but there was no relationship between male MP and climate. This led to increased sexual dimorphism in colder and wetter climates. The same pattern was found after a phylogenetic least squares analysis was conducted to account for shared phylogenetic history. We discuss possible reasons for this pattern, including male,male combat and the greater necessity of females to feed as efficiently as possible to meet their extremely high energy requirements during lactation. [source] Compositionally Graded Aluminum Oxide Coatings on Stainless Steel Using Laser ProcessingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2007Partha P. Bandyopadhyay A 1.5 mm thick fully dense alumina coating with a composition gradient from 100% Ni,20 wt% Cr at the substrate to 100% alumina on top has been developed on a 316 stainless steel sheet using Laser Engineered Net Shaping (LENSÔ). The gradient coatings showed hardness in the range of 1800,2000 Hv, one of the highest reported so far due to high-density layers. During laser deposition, ,-Al2O3 found to grow along the deposition direction with coarse columnar structure. The inherent advantage of this approach is to control simultaneously both location and composition leading to better interfacial properties of coatings. [source] Influence of the relative humidity on film formation by vapor induced phase separationPOLYMER ENGINEERING & SCIENCE, Issue 4 2003H. Caquineau The formation of polymer films produced by the phase separation process occurring when a cast poly(etherimide)/N-Methyl-2-Pyrrolidone solution was exposed to humid air was studied. It was found that above a relative humidity value of 27%, the films presented a cell-like structure. The size of the cells was shown to decrease when the relative humidity increased. This effect was more pronounced at the film/substrate interface than near the surface. A cell-size gradient from one face of the film to the other was also clearly observed. A phenomenological model has been proposed to explain the morphology obtained by a phase separation induced by the water vapor in the studied system, takin into account thermodynamics and kinetics considerations. In this model, the cell-like structure setting up is shown to result from a nucleation and growth process accompanied by a coalescence coarsening. It was illustrated by a composition path on the ternary phase diagram. It was shown how the relative humidity influenced the film composition leading to the preferential nucleation compared to the growth and coalescence of the cells. Finally, it was found that the cell-size anisotropy resulted in the solvent and non-solvent mass transfers in the film, bringing to the fore the determining role of kinetics. [source] Geochemistry as an aid in archaeological prospection and site interpretation: current issues and research directionsARCHAEOLOGICAL PROSPECTION, Issue 1 2009S. Oonk Abstract Human habitation may significantly affect the chemical soil composition leading to enrichments and depletions of specific chemical elements and the formation of archaeological soils. Prospection and interpretation of sites by means of element analysis of soils requires appropriate and well-tested geochemical methodologies. In this paper element analysis in archaeological prospection and site interpretation is briefly reviewed and three major unresolved issues are discussed: (i) how to distinguish archaeological chemical signals in soils from modern and geogenic signals; (ii) what role do geochemical processes play in the formation of archaeological soils; (iii) how to implement geochemical methods in archaeological research programmes. These issues are addressed with reference to the geochemical literature on retention and sequestration pathways of presumed anthropogenic elements in soils and analytical procedures. Based on the acquired knowledge, several directions for future research are proposed. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||