Concentrate processing terminology

Rate Measures for Interfacial Processes Terminology used for reporting rate data can be confusing. Normally rate data are reported on a volumetric basis with transfer rate and effective area combined. For example, kLa denotes mass-transfer data per unit volume. The L subscript means it is referenced to the molar concentration difference between the interface and the bulk liquid. This is commonly used on data involving a sparingly soluble (high relative volatility) component. Note that the lowercase k means the data deal only with the resistance in the liquid phase. 

The initiators which are used in addition polymerizations are sometimes called catalysts, although strictly speaking this is a misnomer. A true catalyst is recoverable at the end of the reaction, chemically unchanged. Tliis is not true of the initiator molecules in addition polymerizations. Monomer and polymer are the initial and final states of the polymerization process, and these govern the thermodynamics of the reaction the nature and concentration of the intermediates in the process, on the other hand, determine the rate. This makes initiator and catalyst synonyms for the same material The former term stresses the effect of the reagent on the intermediate, and the latter its effect on the rate. The term catalyst is particularly common in the language of ionic polymerizations, but this terminology should not obscure the importance of the initiation step in the overall polymerization mechanism. 

The classification given in Table 1.2 is based on the various forms that corrosion may take, but the terminology used in describing corrosion phenomena frequently places emphasis on the environment or cause of attack rather than the form of attack. Thus the broad classification of corrosion reactions into wet or dry is now generally accepted, and the nature of the process is frequently made more specific by the use of an adjective that indicates type or environment, e.g. concentration—cell corrosion, crevice corrosion, bimetallic corrosion and atmospheric corrosion. 

Notice that the right-hand side of Eq. (34) is equal to the ratio of the transformed concentration at the second measurement point to the transformed concentration at the first measurement point. In the terminology of control engineering, this quantity is the transfer function of the system between Xo and Xm- The Laplace-transform method is possible because the diffusion equation is a linear differential equation. Thus, the right-hand side of Eq. (34) could in principle be used in a control-system analysis of an axial-dispersion process. 

Sixth, approaches should be introduced with pharmacological transparency. A clear understanding of the researcher s biometrical approach (mechanistic assumption) is essential if confusion in mixture toxicology terminology is to be eliminated. The concept of additivity as a basis for an evaluation should be explicitly described as concentration addition, response addition, or another (new) concept, but should not be undefined. We recommend models that facilitate clear interpretation of effects and explicit critical judgment during the processing of data. 

Regression techniques. Principal components are sometimes called abstract factors, and are primarily mathematical entities. In multivariate calibration the aim is to convert these to compound concentrations. PCR uses regression (sometimes called transformation or rotation) to convert PC scores onto concentrations. This process is often loosely called factor analysis, although terminology differs according to author and discipline. 

Descriptions of the continuous processes have been reported in some recent reviews [1,17,18]. After elimination of butadiene, the C4 stream (raffinate-1) is desulfurized with aqueous caustic soda, washed, and thoroughly dried over alumina or silica gel, and then cooled before entering a reactor which is generally of the agitated type. The activator (protogen or initiator in the Kennedy s terminology [1]) is added with the hydrocarbon feed at a concentration that is a few percent of the Lewis acid concentration. When water is used, the process does not necessarily need a specific addition, because the control of drying process can afford the required trace amounts of water for a catalytic initiation. 

In these circumstances, where routine kinetic measurements are uninformative and direct measurements of the product-forming steps difficult, comparative methods, involving competition between a calibrated and a non-calibrated reaction, come into their own. Experimentally, ratios of products from reaction cascades involving a key competition between a first-order and a second-order processes are measured as a function of trapping agent concentration. Relative rates are converted to absolute rates from the rate of the known reaction. The principle is much the same as the Jencks clock for carbenium ion lifetimes (see Section 3.2.1). However, in radical chemistry Newcomb prefers to restrict the term clock to a calibrated unimolecular reaction of a radical, but such restriction obscures the parallel with the Jencks clock, where the calibrated reaction is a bimolecular diffusional combination with and the unknown reaction a pseudounimolecular reaction of carbenium ion with solvent. Whatever the terminology, the practical usefulness of the method stems from the possibility of applying the same absolute rate data to all reactions of the same chemical type, as discussed in Section 7.1. 

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