Segregated heterogeneous material

Admittedly, these words are a mouthful. But fortunately, they are very intuitive and descriptive. CH refers to the differences in the constitution, or makeup, of the material how alike or different the individual particles or molecules are. DH refers to differences in how the material is distributed how well mixed or segregated the material is due to density, particle size, or other factors. Each of these two types of heterogeneity gives rise to a sampling error. Together they determine how variable our samples can be and how easy or hard it is to get consistently representative samples. Because an understanding and assessment of these two types of heterogeneity are important, we need to examine them in detail. 

The GE is a source of sampling variation at the local level that is, at the small scale where the sample is actually taken. It is not present in classical SR. The GE is due to (r) the distribution heterogeneity of the material, which is random at the small scale area where we take our sample, (//) the selection of groups of particles, rather than individual particles, and ( //) the segregation of material at the short range where we take the sample. 

At the mesoscopic scale, interactions between molecular components control the self-organization phenomena between molecular components that lead to random phase-segregation during fabrication of CLs [7]. Mesoscale simulations can describe the morphology of heterogeneous materials and rationalize their effective properties beyond length- and time-scale limitations of atomistic simulations. A recently introduced computational method allows evaluation of the key faetors during fabrication of CLs. These simulations rationalize structural... 

The formation of the microstructure involves the folding of linear segments of polymer chains in an orderly manner to form a crystalline lamellae, which tends to organize into a spherulite structure. The SCB hinder the formation of spherulite. However, the volume of spherulite/axialites increases if the branched segments participate in their formation [59]. Heterogeneity due to MW and SCB leads to segregation of PE molecules on solidification [59-65], The low MW species are accumulated in the peripheral parts of the spherulite/axialites [63]. The low-MW segregated material is brittle due to a low concentration of interlamellar tie chains [65] and... 

In the last two sections the formal theory of surface thermodynamics is used to describe material characteristics. The effect of interfaces on some important heterogeneous phase equilibria is summarized in Section 6.2. Here the focus is on the effect of the curvature of the interface. In Section 6.3 adsorption is covered. Physical and chemical adsorption and the effect of interface or surface energies on the segregation of chemical species in the interfacial region are covered. Of special importance again are solid-gas or liquid-gas interfaces and adsorption isotherms, and the thermodynamics of physically adsorbed species is here the main focus. 

Two of this year s articles discuss the fluid-mechanical aspects of systems where material transfer may occur, accompanied by chemical reaction or heat transfer. Fulford analyzes thin-film flow in terms of the flow regimes and of surface disturbances, and relates recent experimental findings to the theoretical framework. Rietema discusses segregation phenomena in heterogeneous reactions, in relation to conditions of flow and of mass transfer. 

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