Process interactive

All the long-range forces discussed in this chapter play a role in biological processes. Interactions between membranes, proteins, ligands, antibodies... 

Eig. 18. Cycle of downward spiraling performance with unmanaged process interactions. 

Three examples of simple multivariable control problems are shown in Fig. 8-40. The in-line blending system blends pure components A and B to produce a product stream with flow rate w and mass fraction of A, x. Adjusting either inlet flow rate or Wg affects both of the controlled variables andi. For the pH neutrahzation process in Figure 8-40(Z ), liquid level h and the pH of the exit stream are to be controlled by adjusting the acid and base flow rates and w>b. Each of the manipulated variables affects both of the controlled variables. Thus, both the blending system and the pH neutralization process are said to exhibit strong process interacHons. In contrast, the process interactions for the gas-liquid separator in Fig. 8-40(c) are not as strong because one manipulated variable, liquid flow rate L, has only a small and indirec t effect on one controlled variable, pressure P. 

Decoupling Control Systems Decoupling control systems provide an alternative approach for reducing control loop interactions. The basic idea is to use additional controllers called decouplers to compensate for undesirable process interactions. 

The function of the decouplers is to compensate for the undesirable process interactions represented by Gpi9 and Gp9i. Suppose that the process transfer functions are all known. Then the ide design equations are ... 

The most popular and widely used technique for determining the best controller pairing is the relative gain array (RGA) method (Bristol, On a New Measure of Process Interaction, IEEE Trans. Auto. Control, AC-11, 133, 1966). The RGA method provides two important items of information ... 

A measure of the degree of process interactions between the manipulated and controlled variables... 

Jones, A.G., 1985b. Crystallization and downstream processing interactions. In POW-TECH 85, Institution of Chemical Engineers. Sympos. Ser. No. 91. Rugby Institution of Chemical Engineers, pp. 1-11. 

Material and process interaction and their effects on the performance of plastic products are important factors for the designer to understand. It can result in design limitations such as a selected material meeting performance requirements but not pro-cessible by the desired method of fabrication. Most of the limitations that are reviewed in this book can be corrected and do not effect the product performances when qualified people handle the limitations. However they are presented to reduce or eliminate potential problems. 

These are the primary process interactions that the designer must be aware of in order to determine process interference in product performance and design. Specific materials may introduce other problem areas as, for example, air entrapment, differential expansion, and the problem of a level of crystallinity in a crystalline plastic that exceeds the allowed level for stability of a product. 

The process interaction in cast plastic products is mainly involved with the curing processes and with mold filling problems. Voids and porous sections are a frequent problem with castings because the mold filling is done at atmospheric pressure, or low pressure, and if the product has thin sections to fill, the flow may be a problem. 

Figure 9-3 portrays a hypothetical model of how chemical weathering and transport processes interact to control soil thicknesses. The relationship between soil thickness and rate at which chemical weathering can generate loose solid material is indicated by the solid curve. The rate at which transport processes can potentially remove loose solid weathering products is indicated by horizontal dotted lines. The rate of generation by chemical weathering initially increases as more water has the opporhmity to interact with bedrock in the soil. As soil thick-... 

Tundisi JG (1983) A review of basic ecological processes interacting with production and stan-ding-stock of phytoplankton in lakes and reservoirs in Brazil. Hydrobiologia 100 223-243... 

Automatic data processing has been implemented by assigning each specimen to a class. The chromatogram for that specimen can be processed automatically in the same way that the chromatogram of a standard member of the class was previously processed Interactively by the operator. 

During food processing, interactions of antioxidants with proteins and other food constituents take place, and the activity of some antioxidants may change as a result of hydrolytical processes because glycosides and esters are converted... 

For the high resolution case, the phase-contrast effects are automatically introduced owing to the combined effect of defocus and spherical aberration, which gives rise to an image of a structure complicated by the fact that also the amplitude term, resulting from the propagation process, interacts in a non-linear way with the phase term [16,89,90,96]. 

The actual movement of a specific deep-well-injected hazardous substance depends on the types of processes that act on the waste and on the ways in which different processes interact. Figure 20.3 shows the expected change in concentration over time of a deep-well-injected organic compound in an observation well at an unspecified distance from the original point of injection. 

FIGURE 6.2. Aerobic and anaerobic process interactions in a gravity sewer biofilm. 

It is not possible and not a purpose of this text to deal with a great number of specific details of the chemical and microbial processes that are relevant for the different types of collection systems that exist. The number of types and corresponding variability are legion, determined by tradition and site-specific demands. The entire text is, therefore, developed to focus on the general understanding of in-sewer chemical and microbial processes, the conditions for them to proceed and the process engineering of the urban wastewater system. The process interactions between the sewer network and the other parts of the urban wastewater system, in particular, the treatment plant, are important in this respect. 

Other aspects concern the complex temperature impacts of the in-sewer processes. Sewer processes, microbial as well as physicochemical like reaeration, are temperature dependent. The different processes interact, and the overall temperature dependency of a specific phenomenon may therefore not... 

Figure 4. The sputtering process—interaction of primary ions with a sample...

The use of mathematical programming models on an enterprise-wide scale to address strategic decisions considering various process integration alternatives yields substantial benefits. These benefits not only materialize in terms of economic considerations, but also in terms of process flexibility and improvements in the understanding of the process interactions and systems limitations. 

When heat and mass are transferred simultaneously, the two processes interact through the Gr and Gq terms in Eq. (10-12) and the energy and diffusion equations. Although solutions to the governing equations are not available for spheres, results should be qualitatively similar to those for flat plates (T4), where for aiding flows (Gr /Gq > 0) the transfer rate and surface shear stress are increased, and for opposing flows (Gr Gq < 0) the surface shear stress is predicted to drop to zero yielding an unstable flow. 

Cheyne, A., Barnes, J., Gedney, S., Wilson, D. (2005). Extrusion behaviour of cohesive potato stareh pastes II. Microstructure-process interactions. Journal of Food Engineering, 66, 13-24. 

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