Papers by Keyword: Disperse Systems

Abstract: The processes of structure formation in hardening disperse systems are considered from the standpoint of synergetics and catastrophe theory. It is proposed to use a topological approach to identify general patterns of behavior of such systems, based on the possibility of modeling the transition of smooth quantitative changes into radical qualitative ones. Based on the analysis of literary data, a group of curves of the structure formation kinetics is identified, the extreme form of which reproduces the geometry of the simplest catastrophe «fold».Spatial models describing the kinetics of dispersion hardening are constructed and analyzed. It is shown that the agreement between the experimental and model kinetic curves is expressed not only in the external similarity of the nature of the dependencies, but also in their logical generalization.It is noted that the canonical «fold» model can also be effectively applied in the study of anomalousrheological behavior of dispersed systems.

Abstract: To this day, there is a large volume collected of the results of experimental studies on structure changes in various dispersions serving as base for production of most construction materials. The analysis of collected information revealed that there is an entire category of stick-slip phenomena, the case history of which is represented by N-and S-type inflections on rheological, kinetic and other curves. We should emphasis that the view of such non-trivial charts is alike with geometry of standard curves of standard conditions. And this alikeness predetermines the possibility of applying topological models of «fold» and «ruffle» types for studying various abnormal effects. We must also note that besides N- and S-types there is a range of other characteristics («flags») pointing to applicability of the methods of catastrophe theory to studying certain processes initiating the apparition of interruptions in system development. Recognition of above-mentioned particularities allows determining the fact and type of catastrophe, the standardised structure of which facilitates finding strict patterns and thus defines directions of optimisation of various situations of research and practical nature. This work shows that pieces of evidence and consistent patters are reliably interpreted within the framework of the proposed concept.

Abstract: This work presents the results of investigations of the topological characteristics of quartz raw materials of various mineral compositions crushed to the critical state of the dispersed layer under which the shape of the particles and the action of the electrostatic repulsion forces change.

Abstract: The work considers the pre-requisites for the development of a scientific methodology of determination of optimum water content in hard raw mixes used for the production of high-strength concrete. The main idea of the methodology is the capillary structures hypothesis which considers the laws of formation of irregular structures under the conditions of balance of the forces among the particles in three-phase disperse systems. The structure formation under the effects of capillary cohesion in disperse systems has been studied; the capillary cohesion was considered as a factor influencing the formation of the optimum structure of raw mixes for compressed construction composites and determining the strength of the products.