Sequential processing additional information

Visualization of the OMAP is useful to judge the additional information introduced as each new compound is added (Fig. 3.32). Computationally, it is much more efficient to treat the set of noncongeneric compounds simultaneously (111,399), as we shall see, but reassuring when identical results are obtained if one uses the sequential procedure introducing each molecule in turn, where intermediate results may be visually verified. The use of computer graphics to confirm intermediate processing of data in convenient display modes becomes increasingly more important as the individual computations and numbers of molecules under consideration increase. 

For steady-state simulations, several solution methods have been used. The one most frequently used is the sequential approach. In this method, numerical modules are used that calculate the output stream of a process unit from the input streams coupled with any additional information that is required to uniquely define the performance of the process unit. The simulation treats one unit model at a time. For a simulation flow sheet consisting of interconnected units, the order... 

Whereas DNA has a single role as the storehouse of genetic information, RNA plays many roles in the operation of a cell. There are several different types of RNA, each having its own function. The principal job of RNA is to provide the information needed to synthesize proteins. Protein synthesis requires several steps, each assisted by RNA. One type of RNA copies the genetic information from DNA and carries this blueprint out of the nucleus and into the cytoplasm, where construction of the protein takes place. The protein is assembled on the surface of a ribosome, a cell component that contains a second type of RNA. The protein is consfructed by sequential addition of amino acids in the order specified by the DNA. The individual amino acids are carried to the growing protein chain by yet a third type of RNA. The details of protein synthesis are well understood, but the process is much too complex to be described in an introductoiy course in chemistry. 

Consider again a batch polymerization process where the process is characterized by the sequential execution of a number of steps that take place in the two reactors. These are steps such as initial reactor charge, titration, reaction initiation, polymerization, and transfer. Because much of the critical product quality information is available only at the end of a batch cycle, the data interpretation system has been designed for diagnosis at the end of a cycle. At the end of a particular run, the data are analyzed and the identification of any problems is translated into corrective actions that are implemented for the next cycle. The interpretations of interest include root causes having to do with process problems (e.g., contamination or transfer problems), equipment malfunctions (e.g., valve problems or instrument failures), and step execution problems (e.g., titration too fast or too much catalyst added). The output dimension of the process is large with more than 300 possible root causes. Additional detail on the diagnostic system can be found in Sravana (1994). 

In order to simulate sequential activities, the termination of a predecessor activity has to be checked by means of a transition. In addition, the required tools and information as well as at least one person who is able to execute the activity must be available. The example process in Fig. 5.6 contains several sequential activities. Activity 1 and Activity 4 of swim lane 1, for example, are sequential activities that need one tool (catalogue) and some information for their processing. The corresponding activities in the simulation model are presented in Fig. 5.7 on the upper right side. 

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