Classification of processes

The aim of polymer processing is to convert the polymer, usually in the form of powder or granules, into a more useful form. Usually the change involved is largely physical, although in some conversion processes chemical reactions play a part. 

As we have remarked in Chap. 3, the common features of all these processes may be summarised under four headings  

The rheological conditions of these processing techniques arc different. The shear rates, for instance, show enormous differences, as will be clear from the following survey (Table 24.1). 

Each processing technique has to fulfil certain requirements of economy. Often the most economic (i.e. the cheapest) method is the worst from the technological point of view. Commercial processing is always a compromise between the best quality and the lowest cost. 

Three questions of particular importance claim attention  

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External control of the process is achieved by devices that are specially designed, selected and configured for the intended process-control application. The text below covers three very common function classifications of process-control devices controllers, final control elements, and regufators. 

A classification of processes can be made with respecl to the nature of the reaction product, as follows ... 

Part 2 Classification of Process Control Systems Realization, operation and testing of safety instrumented systems (December 1998)... 

Classification of Processes and Reactors. Most styrene polymers are produced by batch suspension or continuous mass processes. Some are produced by batch mass processes. Mass in this sense includes bulk polymerization of the polymer... 

The concepts of structural observability are the basic tools for developing variable classification strategies. Some approaches presented in Chapter 3 are based on the fact that the classification of process variables results from the topology of the system and the placement of instruments and has nothing to do with the functional form of the balance equations. Thus, the linearity restriction will be removed and efficient reduction of the large-scale problem will be accomplished. 

Crowe et al. (1983) proposed an elegant strategy for decoupling measured variables from the linear constraint equations. This procedure allows both the reduction of the data reconciliation problem and the classification of process variables. It is based on the use of a projection matrix to eliminate unmeasured variables. Crowe later extended this methodology (Crowe, 1986, 1989) to bilinear systems. 

Shaw, P.E., Rouseff, R.L., Goodner, K.L., Bazemore, R., Nordby, H.E. Widmer, W.W. (2000) Comparison of headspace GC and electronic sensor techniques for classification of processed orange juices. Lebensm.-Wiss. Technol. 33 331-334. 

Fig. 3.3. Schematic classification of processes in solid with defects, (a) Defect diffusion ...

Figure 84 A classification of processes for printing, contact and non-contact...

A hierarchical classification of processes in respect to their characteristic times underlies, in fact, the theorem on the minimum of the rate of entropy production as well. Let us consider two conjugate processes described by the Onsager equations ... 

The mechanistic conclusions may be summarized as follows, reference being made to the classification of processes at the beginning of Section X,A,1. The basic reactions are five heterolytic dissociative adsorptions and one reaction analogous to a ligand insertion reaction. The first five reactions below represent reaction of Cr3+(cus) + 02 (cus) with deuterium or a hydrocarbon. 

JC Wong, KA McDonald, and A Palazoglu. Classification of process trends based on fuzzified symbolic representation and hidden Markov models. J. Process Control, 8 395-408, 1998. 

Classification of Processed Cheese Products Manufacturing Protocol Principles of Manufacture of Processed Cheese Structure Formation on Cooling Properties of Emulsifying Salts... 

At the preclinical product phase, critical and noncritical classification of process input parameters should be initiated [32]. Critical components of facility subsystem validation need to be essentially complete before phase I product manufacture [15]. For phase I, it is necessary to validate aspects of the process related to product safety (e.g., sterility, mycoplasma, viral clearance, impurity removal, and stability) [14]. Abbreviated viral clearance studies for model viruses/retroviruses and impurity clearance studies for host cell DNA often are acceptable, resulting in fewer downstream steps validated at this product stage [3, 5]. If viral clearance results are available in sufficient time, the results can be applied to developing the phase I process steps. All assays do not have to be validated at this stage, but some (especially product-specific ones) should be at least qualified [14]. 

General classification of process chains suggests a determination of the depth of integration of the product data handling. Classification can be divided into ... 

Figure 2.1. Classification of processes in the valorization of plastic objects as a function of entropy...

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