UNIVERSAL LAW OF THE SPATIAL-PERIODIC NANO- AND MICRO-STRUCTURES EXCITATION DURING THE TRANSIENT COMBUSTION OF ENERGETIC MATERIALS

Author(s):  
Alexander N. Lukin
Author(s):  
V.E. Zarko

The computer code is elaborated for numerical simulation of transient combustion of energetic materials (EM) subjected to the action of time-dependent heat flux and under transient pressure conditions. It allows studying combustion response upon interrupted irradiation (transient pressure) and under action of periodically varied heat flux (pressure) in order to determine stability of ignition transients and parameters of transient combustion. The originally solid EM melts and then evaporates at the surface. It is assumed that chemical transformations occur both in the condensed and gas phases. At the burning surface, the phase transition condition in the form of Clapeyron-Clausius law for equilibrium evaporation is formulated that corresponds to the case of combustion of sublimated or melted EM. The paper contains description of transient combustion problem formulation and several examples of transient combustion modeling. At present time a precise prediction of transient burning rate characteristics is impossible because of the lack of information about magnitude of EM parameters at high temperatures. However, the simulation results bring valuable qualitative information about burning rate behavior at variations in time of external conditions – radiant flux and pressure.


Author(s):  
M.E. Lee ◽  
A. Moller ◽  
P.S.O. Fouche ◽  
I.G Gaigher

Scanning electron microscopy of fish scales has facilitated the application of micro-structures to systematics. Electron microscopy studies have added more information on the structure of the scale and the associated cells, many problems still remain unsolved, because of our incomplete knowledge of the process of calcification. One of the main purposes of these studies has been to study the histology, histochemistry, and ultrastructure of both calcified and decalcified scales, and associated cells, and to obtain more information on the mechanism of calcification in the scales. The study of a calcified scale with the electron microscope is complicated by the difficulty in sectioning this material because of the close association of very hard tissue with very soft tissues. Sections often shatter and blemishes are difficult to avoid. Therefore the aim of this study is firstly to develop techniques for the preparation of cross sections of fish scales for scanning electron microscopy and secondly the application of these techniques for the determination of the structures and calcification of fish scales.


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