Data aggregation example

Consider the Best Buy data in Example 11-3. The three product managers have decided to aggregate and order all three models each time they place an order. Evaluate the optimal lot size for each model. 

Risk screening relies upon generic frequency data to provide conservative approximations of individual and aggregate risks. Table 4.9 offers an example of generic frequencies for major explosions for certain types of refinery process units. A methodology is also offered to predict expected event frequencies where generic data are not available. 

As mentioned before, additives do not come out as contributing to life cycle impacts in any of the 110 case studies reviewed. From the above, it is clear that a straightforward LCA case study using a standard LCI database would indeed not show additives, because they are not present in these databases. The fact that the plastics data are aggregate data masks any omissions, implying it is possible that case study performers were unaware of it. For example the studies on (waste treatment) of plastic packaging [6-12], plastic cup studies [13,14] and some studies on automotive parts [15, 16] do not mention additives at all. 

Table 2.4 shows data for this example (Ierapetritou and Floudas, 1998). Since aggregation entails combination of all the processors in a particular stage, the main distinction from the general formulation is in the capacity constraints and the material balances. These are presented below. 

It is well known that many compounds are able to change their physical form whilst suspended in solution. For example, a compound of interest may change from one polymorphic form to another, while different crystalline aggregations of the same compound can have different solubility profiles. Impurities can mask the true solubility, and aggregation in solution can also change the thermodynamic equilibrium. Finally, errors which have been published in the literature data may in fact magnify from publication to publication. 

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