Onion model

Figure 1.6 The onion model of process design. A reactor design is needed before the separation ind recycle system can be designed, and so on. (From Smith and Linnhoff, Trans. IChemE, CkERD, 66 195, 1988 reproduced by permission of the Institution of Chemical Engineers.)...

After maximizing heat recovery in the heat exchanger network, those heating duties and cooling duties not serviced by heat recovery must be provided by external utilities. The outer-most layer of the onion model is now being addressed, but still dealing with targets. 

Figure 8.3 Overall cost tradeoffs decomposed according to the onion model.

FIG. 4 Onion model of spherical water-containing reversed micelles. Solvent molecules are not represented. A, surfactant alkyl chain domain B, head group plus hydration water domain C, hulk water domain. (For water-containing AOT-reversed micelles, the approximate thickness of layer A is 1.5 nm, of layer B is 0.4 nm, whereas the radius of C is given hy the equation r = 0.17R nm.)... 

Figure 1.7 The onion model of process design. A reactor is needed before the separation and recycle system can be designed and so on. 

Pinch analysis as a tool of process integration could be applied here as in most cases drying and all its downstream and upstream processes are necessarily bound to form a hierarchical structure, adequately represented by the onion model [25]. 

Summarising, the whole idea behind the onion model seems to depict the essence of culture as something hidden rather deeply under a layered set of more or less visible manifestations upon which it exerts its influence. These layers can function as a key to the nature of the underlying culture. ... 

In a nutshell there are two families of energy functions that are used in threading computations, namely the pairwise models (with identifiable pair interactions) and the profile models. In this section we formally define both families and we also introduce a novel THreading Onion Model (THOM), which is investigated in the subsequent sections of the chapter. 

We consider two profile models. The first, which is very simple, was used in the past as an effective solvation potential [1,2,42], We call it THOMl (THread-ing Onion Model 1), and it suggests a clear path to an extension (which is our prime model), namely, THOM2. The onion level denotes the number of contact shells used to describe the environment of the amino acid. The THOMl model uses one contact shell of amino acids. The more detailed THOM2 energy model (to be discussed below) is based on two layers of contacts. 

Different strategies can be adopted to partition the sy.stem. The simplest approximation is to divide the. system into three regions - a QM region and an MM region surrounded by a boundary. However, it is possible to envi.sage a. system partitioned into multiple regions in which less sophisticated potentials are used as the distance from the central core increases (see Figure I). Such onion models have been... 

Once incorporation is accomplished, carbon black agglomerates break into aggregates via the onion model mechanism. When agglomerates practically disappear and disintegrate into aggregates, the mixing is considered to be complete. However, every portion of the compound must have the same composition namely distributive mixing is also important and must occur simultaneously with dispersion. 

The above outlines of the model deal with the macroscopic changes. The details remain to be refined. The remaining problem lies in the differences between macroscopic and microscopic deformation. With the progress of incorporation, this problem becomes critical. In pursuing the progress of dispersion, in what way is the onion model related to matrix deformation As modelled in Figure 11.6(a) and (b) [22], the agglomerate particle... 

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