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General Assumptions

We make the following simplifying and reasonable assumptions in developing the model. [Pg.475]

The dense emulsion phase is perfectly mixed and is at incipient fluidization conditions with constant voidage. [Pg.475]

The flow of gas in excess of the minimum fluidization requirement passes through the bed in the form of bubbles. [Pg.475]

The bubbles are spherical, of uniform size, and in plug flow. [Pg.476]

Polymerization occurs only in the emulsion phase and no reaction occurs in the bubble phase. [Pg.476]

We consider a one-component liquid phase containing N homogeneous open chain r-mer molecules. We assume that a r-mer may be treated as a set of r point-centres each of which is subjected to a S3rstem of central forces exerted by the centres of the neighbouring molecules. The potential energy between two point centres of different r-mers is assumed to be given by the two parameter law (2.4.2) [Pg.324]

The cntenon for the existence of a lattice is that the mean distance between neighbouring point-centres is approximately the same whether they belong to the same r-mer or not. Let us denote by a the mean distance between two neighboring elements belonging to different -mers and by d the distance between two successive elements of the same -mer. The criterion for the lattice may then be formulated by the conditions [Pg.324]

Now is a fimction of tmnperature and pressure while d and r are molecular constants. Let us suppose [Pg.324]

Then n bcting interactions between elements which are not first ne bbouis we have at absolute zero [Pg.324]

If the criterion (16.2.2) for the existence of a lattice is satisfied we may apply the cell method for the evaluation of the configurational partition function (Pkigogine, Trappeniers and Mathot [1953 a, b]). The result will clearly be of the form (7.1.2) [Pg.325]


Plants, situations, and causes of overpressure tend to be dissimilar enough to discourage preparation of generalized calculation procedures for the rate of discharge. In lieu of a set procedure most of these problems can be solved satisfactorily by conservative simplification and analysis. It should be noted also that, by general assumption, two unrelated emergency conditions will not occur simultaneously. [Pg.17]

In formulating tlie phm, some general assumptions may be made. [Pg.88]

Several authors, notably Leland and co-workers (L2), have discussed vapor-liquid equilibrium calculations based on corresponding-states correlations. As mentioned in Section II, such calculations rest not only on the general assumptions of corresponding-states theory, but also on the additional assumption that the characterizing parameters for a mixture do not depend on temperature or density but are functions of composition only. Further, it is necessary clearly to specify these functions (commonly known as mixing rules), and experience has shown that if good results are to be obtained, these... [Pg.172]

It will be noted that applying the present approximation for the analysis of the stability of capillary flow at high heat fluxes corresponding to the domain 0 < Xf < x[ is purely symbolic, since the general assumption that Pol < 1 is not valid at... [Pg.453]

Efforts to achieve a retardation of cross-linking in elastomers are based on the general assumption of a radical mechanism for retardation cross-linking and the possibility of its inhibition by a deactivation of the reactive macromolecular radical [33]. These compounds generally contain one or more labile hydrogen atoms, which after, donation of this atom, will form relatively inactive radicals. Typical antirad agents are quinones, hydroquinones, and aromatic amines (phenyl and napthylamines). [Pg.864]

It is important to note that most molecules are not rigid but may prefer a distrinct structure and the conformation of a molecule strongly depends on its specific environment. Hence, the crystal structure of a drug does not have to correspond to the receptor bound conformation. Also, a conformation in solution depends on the nature of the solvent and measuring conditions, and may change when the molecule is bound to the receptor [4]. In addition, different receptors or receptor subtypes can bind the same drug in different conformations. It is a general assumption and observation, but by far not a strict condition, that the conformation in aqueous solution is similar to the bound conformation and is a better representation of the bioactive conformation than an X-ray structure of the isolated molecule in the crystalline state. [Pg.210]

There is yet another possibility. The general assumption is that the effect of a drug adds to the placebo effect, so that the total improvement that patients experience is the drug effect in addition to the placebo effect. This assumption is implicit in the design of placebo-controlled clinical trials, in which the drug effect is assessed as the difference between the response to the drug and the response to the placebo. Anne Harrington, an historian of science at Harvard University and the London School of Economics, calls it the oil-and-water hypothesis. [Pg.77]

The mathematical model describing the two-phase dynamic system consists of modeling of the flow and description of its boundary conditions. The description of the flow is based on the conservation equations as well as constitutive laws. The latter define the properties of the system with a certain degree of idealization, simplification, or empiricism, such as equation of state, steam table, friction, and heat transfer correlations (see Sec. 3.4). A typical set of six conservation equations is discussed by Boure (1975), together with the number and nature of the necessary constitutive laws. With only a few general assumptions, these equations can be written, for a one-dimensional (z) flow of constant cross section, without injection or suction at the wall, as follows. [Pg.502]

These reduced compounds are found in living organisms, natural gas, oil and coal. Now clearly this situation is not one of equilibrium and forces us to look again at our general assumption that as oxygen partial pressure changed the elements in the... [Pg.29]

A. General assumptions and geometric structure of the non-perturbed system... [Pg.114]

In my original paper I stressed the circumstance that I was unable to give a logical reason for the exclusion principle or to deduce it from more general assumptions.. .. Of course in the beginning I hoped that the new quantum mechanics, with the help of which it was possible to deduce so many half-empirical formal rules in use at the time, will also rigorously deduce the exclusion principle.24... [Pg.249]

Excipient compatibility studies are a form of preliminary stability assessment. It is important that they be executed appropriately. The precise details of the testing will probably be different for each organization carrying out such studies. However, certain general assumptions are implicit in this approach. The underlying principle is the Arrhenius relationship ... [Pg.101]

Toxicity data are used to assess occupational exposure hazards associated with materials used in a process and are communicated through the use of Permissible or Occupational Exposure Limits (PEL or OEL). OELs are usually set based on a combination of the inherent toxicological hazard of a chemical and a series of safety factors such as intra-species variability in test results, the nature and severity of the effect, and the adequacy and quality of the information. OELs are set to protect workers under the general assumption that they are being exposed to any... [Pg.40]

Reactor systems, in which the following general assumptions are valid, are preferable ... [Pg.96]


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