Model Morphology

Ischemic AKI may be induced by intrarenal norepinephrine injection or by renal artery clamping. There are similarities between these two models of ischemic renal failure. In the norepinephrine model of renal failure, as in the arterial clamping model, there is the same degree of tubular injury except for a slightly greater frequency of tubular casts at 48 hours in ischemic model [32]. In both models, calcium channel-blockers, improve renal function [33, 34]. The major difference is that in the renal artery clamping model, morphology at 48 hours showed smooth muscle necrosis in half of the resistance vessels, but in less than 10% of those in norepinephrine-induced model. 

Figure 16.10. Model morphology shown by two-dimensional cut for carbon black filled blend. [Adapted, by permission, from Knackstedt M A, Roberts A P, Macromolecules, 29, No,4, 1996, 1369-71.]...

Macrophage antibacterial functions in experimental protein -calorie malnutrition. I. Description of the model, morphologic observations and macrophage surface IgG receptors, J. Infect. Dis. 138 125. 

Examples for the application of mesh-free methods to the question of structure formation can indeed be found for drying processes. Ito and Yukawa modelled the evolution of cracks within a drying paste by the use of the mesh-free SPH method [6]. Karunasena et al. simulated drying and shrinkage of cells in food stuff with a coupled SPH-DEM approach [7]. These models have been developed parallel and independently to our work and address very different kind of drying mechanisms. StiU, they underline the applicability of a mesh-free approach to modelling morphology evolution. 

Modelling Morphology Evolution Within a Single Slurry Droplet hy SPH... 

Table 1 Ratios of Consecutive Bragg Spacings for Different Model Morphologies...

Figure 18 Morphology diagram generated by the Milner model. Morphology is given for the volume fraction of the B component, 5b, and molecular asymmetry, e (where and /Jb are the numbers of arms of block materials A and B, respectively, and /, = = Vi/b, with V ...

Qualitative examples abound. Perfect crystals of sodium carbonate, sulfate, or phosphate may be kept for years without efflorescing, although if scratched, they begin to do so immediately. Too strongly heated or burned lime or plaster of Paris takes up the first traces of water only with difficulty. Reactions of this type tend to be autocat-alytic. The initial rate is slow, due to the absence of the necessary linear interface, but the rate accelerates as more and more product is formed. See Refs. 147-153 for other examples. Ruckenstein [154] has discussed a kinetic model based on nucleation theory. There is certainly evidence that patches of product may be present, as in the oxidation of Mo(lOO) surfaces [155], and that surface defects are important [156]. There may be catalysis thus reaction VII-27 is catalyzed by water vapor [157]. A topotactic reaction is one where the product or products retain the external crystalline shape of the reactant crystal [158]. More often, however, there is a complicated morphology with pitting, cracking, and pore formation, as with calcium carbonate [159]. 

Lamellar morphology variables in semicrystalline polymers can be estimated from the correlation and interface distribution fiinctions using a two-phase model. The analysis of a correlation function by the two-phase model has been demonstrated in detail before [30,11] The thicknesses of the two constituent phases (crystal and amorphous) can be extracted by several approaches described by Strobl and Schneider [32]. For example, one approach is based on the following relationship ... 

An even coarser description is attempted in Ginzburg-Landau-type models. These continuum models describe the system configuration in temis of one or several, continuous order parameter fields. These fields are thought to describe the spatial variation of the composition. Similar to spin models, the amphiphilic properties are incorporated into the Flamiltonian by construction. The Flamiltonians are motivated by fiindamental synnnetry and stability criteria and offer a unified view on the general features of self-assembly. The universal, generic behaviour—tlie possible morphologies and effects of fluctuations, for instance—rather than the description of a specific material is the subject of these models. 

The microstmcture and morphology of thick single-phase films have been extensively studied for a wide variety of metals, alloys, and refractory compounds. The stmcture model first proposed is shown in Figure 6 (10). It was subsequently modified as shown in Figure 7 (I0,II). 

Microscopic identification models ate similar to the CMB methods except that additional information is used to distinguish the source of the aerosol. Such chemical or morphological data include particle size and individual particle composition and are often obtained by electron or optical microscopy. 

For thin-film samples, abrupt changes in refractive indices at interfrees give rise to several complicated multiple reflection effects. Baselines become distorted into complex, sinusoidal, fringing patterns, and the intensities of absorption bands can be distorted by multiple reflections of the probe beam. These artifacts are difficult to model realistically and at present are probably the greatest limiters for quantitative work in thin films. Note, however, that these interferences are functions of the complex refractive index, thickness, and morphology of the layers. Thus, properly analyzed, useful information beyond that of chemical bonding potentially may be extracted from the FTIR speara. 

S. Suresh and R. O. Ritchie, A Geometric Model for Fatigue Crack Closure Induced by Fracture Surface Morphology , Metallurgical Transactions, 13A, 1982, pp. 1627 1631. 

Fig. 2. Morphology model of a core-shell, rubber-toughened epoxy adhesive.

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