Using the ICP-MS method we have studied the isotope systematics of Sr and Nd as well as trace element composition of a representative collection of kimberlites and related rocks from the Siberian Platform. The summarized literature and our own data suggest that the kimberlites developed within the platform can be divided into several petrochemical and geochemical types, whose origin is related to different mantle sources. The petrochemical classification of kimberlites is based on persistent differences of their composition in mg# and in contents of indicator oxides such as FeOtot, TiO2, and K2O. The recognized geochemical types of kimberlites differ from one another in the level of concentration of incompatible elements as well as in their ratios.
Most of isotope characteristics of kimberlites and related rocks of the Siberian Platform correspond to the earlier studied Type 1 basaltoid kimberlites from different provinces of the world: Points of isotopic compositions are in the field of primitive and weakly depleted mantle. An exception is one sample of the rocks from veins of the Ingashi field (Sayan area), which is characterized by the Sr and Nd isotopic composition corresponding to Type 2 micaceous kimberlites (orangeites).
The most important feature of distribution of isotopic and trace-element compositions (incompatible elements) is their independence of the chemical rock composition. It is shown that the kimberlite formation is connected with, at least, two independent sources, fluid and melt, responsible for the trace-element and chemical compositions of the rock. It is supposed that, when rising through the heterogeneous lithosphere of the mantle, a powerful flow of an asthenosphere-derived fluid provoked the formation of local kimberlite chambers there. Thus, the partial melting of the lithosphere mantle led to the formation of contrasting petrochemical types of kimberlites, while the geochemical specialization of kimberlites is due to the mantle fluid of asthenosphere origin, which drastically dominated in the rare-metal balance of a hybrid magma of the chamber.
The biological activity of chitosan determines its broad application as a biopolymer for non-woven wound dressings fabricated by electrospinning. The electrospinning process is affected by a large number of different factors that complicate its optimization. In the present work, the electrospinning of chitosan lactate was carried out using a needleless technique from water solutions of different compositions. Surface response methodology was used to evaluate the effects of the concentration of chitosan, polyethylene oxide, and ethanol on solution properties, such as viscosity, surface tension, and conductivity, as well as the process characteristics and fiber quality. The viscosity of the spinning solution is determined by the polymer concentration as well as by the interpolymer interactions. The addition of ethanol to the spinning solutions effectively decreases the solution surface tension and conductivity, while increasing the volatility of the solvent, to provide more intense fiber spinning. Atomic force microscopy revealed that the chitosan lactate fibers were obtained without defects and with a narrow thickness distribution. The spinning parameters, voltage, distance between electrodes, and rotation speed of the spinning electrode had insignificant influences on the fiber diameter during needleless electrospinning.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.