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Composite networks models

Another inconsistency of the earlier network model concerns the implications that it has for phenomena in the composition region around 10% M Oy. This is an important composition region. Experimentally, whether one measures the composition dependence of the heat of activation for viscous flow, of expansivity, of compressibility, or... [Pg.739]

Consider the situation as one decreases the 0/R ratio, i.e., decreases the mole percent of the metallic oxide Mj Oy Between 100 and 66% there is little need for special modeling because the quadrivalency of silicon and the requirements of stoichiometry demand that the ionic species present he monomers of SiO tetrahedra. It is in the composition range of 66 to 10% M that the network model fails (see Section 5.13.7) in the face of facts. [Pg.740]

When the composite objects representing new model classes are generated, their parts constituent are created as more specialized subclasses of the modeling elements of the NETWORK-MODEL KB. However, all the specialized entities constituting model classes are stored in the LIBRARY KB. [Pg.87]

Reference 70 provides the first quantitative test of the random resistor network model. In Ref. 121 the authors employed the random resistor network model to determine the behavior of the low-field Hall effect in a 3D metal-nonmetal composite near the percolation threshold. For the following power laws of effective values of ohmic conductivity a, Hall coefficient R, and Hall conductivity a 12, Bergman et al. 121 have obtained the critical exponents ... [Pg.188]

Borosy, A. Quantitative composition-property modelling of rubber mixtures by utilising artificial neural networks. Chemomet. Intell. Lab. Syst. 1999, 47, 227-238. [Pg.525]

In the next section we will present the data and arguments on which the cluster-network model is based. We will also discuss the effects of equivalent weight, ion form, and water content on the dimensions and composition of the clusters. In the third section we will present a formalism, which follows from the cluster-network model, based on absolute reaction rate theory (2) and hydroxyl rejection in "Nation perfluorinated membranes. Finally we will outline the concepts of percolation theory and demonstrate that ion transport trough "Nation" is well described by percolation. [Pg.283]

There are different ways to depict membrane operation based on proton transport in it. The oversimplified scenario is to consider the polymer as an inert porous container for the water domains, which form the active phase for proton transport. In this scenario, proton transport is primarily treated as a phenomenon in bulk water [1,8,90], perturbed to some degree by the presence of the charged pore walls, whose influence becomes increasingly important the narrower are the aqueous channels. At the moleciflar scale, transport of excess protons in liquid water is extensively studied. Expanding on this view of molecular mechanisms, straightforward geometric approaches, familiar from the theory of rigid porous media or composites [ 104,105], coifld be applied to relate the water distribution in membranes to its macroscopic transport properties. Relevant correlations between pore size distributions, pore space connectivity, pore space evolution upon water uptake and proton conductivities in PEMs were studied in [22,107]. Random network models and simpler models of the porous structure were employed. [Pg.30]

The birefiingence of the polymer network was estimated by measuring the birefringence after replacing the liquid crystal solvent with an isotropic solvent such as octane. The birefiingence of the liquid crystal composite was modeled as follows. The polymer network was assumed to be a square array of parallel fibrils of radius R and order parameter Sp. The order parameter of the liquid crystal solvent was assumed to be equal to that of the polymer network at the interface, and continuously decreasing away from this interface. [Pg.517]

The effects of capillary condensation were included in the network model, by calculating the critical radius below which capillary condensation occurs based on the vapor composition in each pore using the multicomponent Kelvin Equation (23.2). Then the pore radius was compared with the calculated critical radius to determine whether the pore is liquid- or vapor-filled. As a significant fraction of pores become filled with capillary condensate, regions of vapor-filled pores may become locked off from the vapor at the network surface by condensate clusters. A Hoshen and Kopelman [30] algorithm is used to identify vapor-filled pores connected to the network surface, in which diffusion and reaction continue to take place after other parts of the network filled with liquid. It was assumed that, due to the low hydrogen solubility in the liquid, most of the reaction takes place in the gas-filled pores. The diffusion/reaction simulation is repeated, including only vapor-filled pores connected to the network surface by a pathway of other vapor-filled pores. [Pg.612]

This is a landmark paper on the nature of the vitreous body, describing the mechanochemical (or double-network ) model. This model explains satisfactorily the correlations between some properties of the vitreous (composition, rheology, volume, cell population, transparency) and the physicochemical principles governing its stability (frictional interaction, expansion/contraction, the excluded-volume concept, and the molecular-sieve effect). [Pg.129]

Another stream of the study of temporal networks concerns a model network whose history involves cross-links added at a certain stage, a part of which is subsequently removed so as not to be present in the final stage of deformation (called an addition-subtraction network). On the basis of such model composite networks, Flory [14] calculated the stress relaxation, and found that it obeys slow dynamics including a logarithmic dependence of the stress, which is closer to power law rather than exponential. [Pg.282]

Boccorh RK, Paterson A (2002) An artificial neural network model for predicting flavour intensity in blackcurrant concentrates. Food Qual Prefer 13(2) 117-128 Ceballos-Magana SG, de Pablos F, Jurado JM, Martin MJ, Alcazar A, Muniz-Valencia R, Izquierdo-Homillos R (2013) Characterisation of tequila according to their major volatile composition using multilayer perceptron neural networks. Food Chem 136(3) 1309-1315... [Pg.433]

Hayajneh, M.T., Hassan, A.M. and Mayyas, A.T. (2009) Artificial neural network modeling of the drilling process of self-lubricated aluminum/alumina/graphite hybrid composites synthesized by powder metallurgy technique, J Alloys Compd, 478 559-65. [Pg.256]

This paper mainly summarizes the introduction of Song s transient double-network model, non-linear viscoelasticity of double-network formed by twice curing and non-linear viscoelasticity of the NR/ZDMA composite with ionic and covalent crosslink networks. [Pg.188]

Efforts of polymer scientists and fuel cell developers alike are driven by one question What specific properties of the polymeric host material determine the transport properties of a PEM, especially proton conductivity The answer depends on the evaluated regime of the water content. At water content above kc, relevant structural properties are related to the porous PEM morphology, described by volumetric composition, pore size distribution and pore network connectivity. As seen in previous sections, effective parameters of interest are lEC, pKa, and the tensile modulus of polymer walls. In this regime, approaches familiar from the theory of porous media or composites (Kirkpatrick, 1973 Stauffer and Aharony, 1994), can be applied to relate the water distribution in membranes to its transport properties. Random network models and simpler models of the porous structure were employed in Eikerling et al. (1997, 2001) to study correlations between pore size distributions, pore space connectivity, pore space evolution upon water uptake, and proton conductivity, as will be discussed in the section Random Network Model of Membrane Conductivity. ... [Pg.126]

Fig. 3 depicts the composition to realize the Model A — to — ModelB communication by using a composition network. The composition is performed by superposing the transition outinterface of the Model A with the transition T of the composition network, and the place P of the composition network with the place inInterface of the Model B. The communication is guaranteed by the added arc. Superposition techniques are described in the literature, e.g. in [4]. [Pg.236]

Zidek J and Jancar J (2006) Simulation of inelastic stress-strain response of nano-composites by a network model, Key Eng Mater 334-335 857-860. [Pg.284]


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See also in sourсe #XX -- [ Pg.208 ]




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