Speculative processes

Fig. 5. Schematic of speculated process in the emergence of a new branch. A fragile defect of the gel layer is ruptured, and a new branch is formed as the sol spouts from the defect. The branch rapidly develops through self-repairing process of the defect.

All processes in a supply chain fall into one of two categories, depending on the timing of then-execution relative to end customer demand. With pull processes, execution is initiated in response to a customer order. With push processes, execution is initiated in anticipation of customer orders based on a forecast. Pull processes may also be referred to as reactive processes because they react to customer demand. Push processes may also be referred to as speculative processes because they respond to speculated (or forecasted), rather than actual, demand. The pusWpull boundary in a supply chain separates push processes from pull processes, as shown in Figure 1-5. Push processes operate in an uncertain environment because customer demand is not yet known. Pull processes operate in an environment in which customer demand is known. They are, however, often constrained by inventory and capacity decisions that were made in the push phase. 

Domestic. Estimates of U.S. uranium resources for reasonably assured resources, estimated additional resources, and speculative resources at costs of 80, 130, and 260/kg of uranium are given in Table 1 (18). These estimates include only conventional uranium resources, which principally include sandstone deposits of the Colorado Plateaus, the Wyoming basins, and the Gulf Coastal Plain of Texas. Marine phosphorite deposits in central Elorida, the western United States, and other areas contain low grade uranium having 30—150 ppm U that can be recovered as a by-product from wet-process phosphoric acid. Because of relatively low uranium prices, on the order of 20.67/kg U (19), in situ leach and by-product plants accounted for 76% of total uranium production in 1992 (20). 

The accuracy of QRA results is also dependent on the analysis resources. Obviously, more complete QRA models can produce more accurate results. But even the best model is worthless if the input data are speculative or erroneous. Fortunately, the scarcity of process-specific data for some applications may not be an insurmountable problem. There exist a few industrywide databases, such as those in Table 2, that... 

According to an early historical overview (Jones 1960), the numerous attempts to understand the sintering process in both ceramics and metals fall into three periods (1) speculative, before 1937 (2) simple, 1937-1948 (3) complex, 1948 onwards. The complex experiments and theories began just at the time when metallurgy underwent its broad-based quantitative revolution (see Chapter 5). 

Benson and Ponton (1993) and Ponton (1996) have speculated on the ultimate results of continuing efforts for process minimization. They envision a twenty-first century chemical industry totally revolutionized by technological innovation, automation, and miniaturization. Small, distributed manufacturing facilities would produce materials on demand, at the location where they are needed. Raw materials would be nonhazardous, and the manufacturing processes would be waste free and inherently safe. While their vision of future technology is speculative, we are beginning to see progress in this direction. 

Kletz, T. A. (1991). Tresent Trends in Process Safety. Speculations in Science and Technology, Developments in Chemical Engineering 15, 2, 83-90. 

The solid plates that resulted from the cooling process at the surface of the eanli were able to float on the remaining molten inner portion of the earth. Because of the rotational motion of the earth about its own axis and the earth s motion in the solar system, inertial and gravitational forces have produced great interactive forces between the plates. It is speculated that these interactive forces have led to plate contact and situations where one plate has slid over another. The great forces created by plate tectonics are likely responsible for the forces that have resulted in the folding and faulting of the earth s crust [30j. 

Langton s tentative answer to the question above is therefore We expect that information processing can emerge spontaneously and come to dominate the dynamics of a physical system in the vicinity of a critical phase transition. Langton speculates that the dynamics of phase transitions is fundamentally equivalent to the dynamics of information processing. 

We will not go any further into the interesting speculations Minsky offers in his 1982 paper [minsky82]. The point of these speculations was not to propose a serious alternative model of fundamental physics, per se, but to stimulate thinking along the. lines of What if physics were, fundamentally, discrete How would we describe the processes we now think we iinderstaiul with our continuous models Two questions that we will repeatedly come back to in this concluding chapter. 

A vast range of symmetrical and unsymmetrieal 1,6-diene monomers has now been prepared and polymerized and the generality of the process is well established.98,1 A summary of symmetrical 1,6-dienc structures, known to give cyclopolymerization, is presented in Table 4.4 In many cases, the structure of the repeat units has not been rigorously established. Often the only direct evidence for cyclopolymerization is the solubility of the polymer or the absence of residual unsaturalion. In these cases the proposed repeat unit structures are speculative. 

Speculations on the application of the theory of ergons to chemical processes are also put forward.(13) From a knowledge of the r-values of all the atoms in a molecule, the potential energy of the latter may, in simple cases, be calculated, and this is, at low temperatures, equal to the heat of dissociation. 

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