Processes Creation

The first of these system-level transformations, the Process Creation transformation, creates a process from the specified vtbody and its children. It marks the vtbody as a process, replaces each CALL to the vtbody with a SEND / RECV pair of message-passing operators, replaces each LEAVE from the vtbody with another SEND / RECV pair, and RESTARTS the vtbody so that it will execute continuously. The new process will execute concurrently with the other processes, and will be synthesized with a separate data path and controller. 

Process Creation may be used to split a design in response to physical constraints, so that instead of producing a design with one large controller and one large data path that can not fit into the available chip area, two or more smaller controllers / data paths are produced, each of which can fit onto a single chip. This can result in potential for increased concurrency, in smaller data paths on each chip (but more total hardware), and in less total microcode. Each of these effects will be considered in the following sections. 

Process Creation also results in a potential for increased concurrency. Before the transformation, one vtbody CALLs another. 

After Process Creation, the combined amount of microcode for the two resulting controllers may be smaller than the amount before the transformation. This can be shown as follows. Assume that before Process Creation is applied, the design contains m control steps, each corresponding to a microword. Further, assume that in each control step, s bits are required to specify the next control step (the next state), 0 bits are required to specify the microoperation to be performed (jump, jump to subroutine, continue, etc.), and d bits are required to control the data path. The total amount of microcode, nC, is then equal to the number of microwords multiplied by the width of each microword  

If the design is then split into two processes using Process Creation, extra control steps Am might be added, extra bits Asj and As might be required in each process to specify the next control step, and extra bits Adi Ad2 might be required to control new data path elements. 

After studying this chapter, the reader should 

Understand how to go about assembling design data and creating a preliminary database. 

Be able to implement the steps in creating flowsheets involving reactions, separations, and T-P change operations. In so doing, many alternatives are identified that can be assembled into a synthesis tree containing the most promising alternatives. 

Know how to select the principal pieces of equipment and to create a detailed process flow diagram, with a material and energy balance table and a list of major equipment items. 

Understand the importance of building a pilot plant to test major pieces of equipment where some uncertainty exists. 

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D. Resonant Processes—Creation of Coherent Superposition of States—Half-Scrap... 

Przybytniak et al. have drawn similar conclusions in the case of a non-miscible PE/styrene-butadiene-styrene (SBS) blend. The authors assumed that both polymers are characterized by different initial amounts of radicals and differenf rafes of their decays. Moreover, the whole process (creation of radicals and rafes of decay) is not a simple sum of the processes occurring in PE and SBS, even if these polymers are phase separated. 

Throughout Chapters 1 and 3, the role of die process simulators is deemphasized. Rather, emphasis is placed on the steps in process synthesis and the development of the base-case design. Although from time to time these chapters refer to simulation results, a formal discussion of the role of process simulators during process creation is not attempted until Chapter 4 (and the accompanying multimedia CD-ROM). Chapter 3 introduces the steps in process synthesis without discussing many of the key heuristics used in making decisions. A more formal treatment is reserved for Chapter 5. 

Summary In summary, extensive work to find the molecules, usually proteins, that have the appropriate therapeutic properties begins in the step to Create and Assess the Primitive Problem. This work continues into the step to Find Chemicals or Chemical Mixtures Having Desired Properties and Performance, which is introduced in the next section. Then, as Phases 1 and 2 of the Clinical Trials proceed, process design is undertaken to produce large quantities of the drug, first for Phase 3 testing and then for conmiercial operation, as discussed in Chapter 3, Process Creation, in Section 3.4 for a plant to produce tissue plasminogen activator. 

As shown in Figure 1.2, in developing a base-case design, the design team checks regularly to confirm that the process remains promising. When this is not the case, the team often returns to one of the steps in process creation or redevelops the base-case design. 

Finally, before leaving this topic, the reader should note that process creation and development of a base-case process are the subjects of Part One of this book, entitled Product and Process Invention— Heuristics and Analysis (Chapters 1-5.)... 

This chapter covers many of the steps under the blocks of Process Creation and Development of Base Case in Figure 1.2, which provides an overview of the steps in designing new chemical products and processes. These are two of the major blocks on which design teams concentrate much of their effort. 

In some cases, it may be desirable to estimate the prices of utilities, such as steam, cooling water, and electricity, during process creation. Here also, appropriate prices can be obtained from local utility companies. As a start, however, values are often tabulated, as provided in Table 17.1. 

Understand the role of process simulators in process creation and be prepared to lean about their roles in equipment sizing and costing, profitability analysis, optimizatira, and dynamic simulation in the chapters that follow. 

Be able to use the process simulators systematically during process creation, following sequences similar to those illustrated later in this chapter for a toluene hydrodealkylation process. The reader will learn to simulate portions of the process (the reactor section, the distillation section, etc.) before attempting to simulate the entire process with its recycle loops. Many examples and exercises enable the reader to master these techniques. 

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