Chronological time

In Eq. 24 the activity varies with the chronological time. To eliminate this quantity integrate Eq. 146 (see Eq. 18) and insert in Eq. 24. Thus... 

During Trevor Kletz s classes, he always wanted to know, Why did it happen at the exact time that it did This question is not looking for the specific chronological time, but relates to a unique time when some significant manpower, process, or hardware conditions were different from normal. It could be a time when a new catalyst was used, when the vessel that had just been opened and contained an undetected heel of fuming solids, or operating when the protective analyzer was out of service. 

If one worker requires ten days to perform one activity, it may be argued that ten workers could perform it in one day. Unfortunately, that is not the case in project execution all projects involve hundreds, even thousands, of activities, many of which must be performed sequentially. If the activities to be performed in ten days were ten sequential ones instead of a single activity, ten workers could not perform them in one day. More likely, they would perform them in three or four days expending thirty or forty man-days instead of ten. The shortest possible schedule is dictated by the longest string of sequential activities as well as the minimum chronological time and labor hours required to perform each one. The duration of the construction effort is dependent on a number of factors ... 

This observation led Dedrick et al. (3) to demonstrate that methotrexate plasma concentration vs. time data for several species were superimposable when plasma concentrations were normalized for dose/(body weight) and chronological time was converted to an equivalent time" by dividing it by body weight raised to the 0.25 power. This was an empirically determined parameter for methotrexate. The form of the correlation should be useful for interspecies plasma concentration data for other drugs — particularly those that are not metabolized. The exponent on body weight could be determined empirically but would be expected to be similar to that for methotrexate. 

Establishing Chronologies Time Scales of Accumulation and Bioturbation.153... 

Another characteristic of catalytic reactions is that it cannot in general be assumed, once reaction is established at a certain rate under given conditions, that the rate will remain constant with the passage of chronological time. Catalysts normally lose some or all of their specific activity for a desired chemical transformation with time of utilization. This effect, normally referred to as deactivation, can come from a number of different sources and is often very important in the analysis and/or design of catalytic processes and reactors. 

Equation (3-102) has the familiar LH adsorption terms in the denominator, but differs by the appearance of JF4 in the numerator. The difference (Tq — X4) corresponds to the undeactivated surface accordingly equation (3-102) shows that the concentration of unoccupied sites is proportional to the number of undeactivated sites, and the reaction rate is also proportional to (Zq — X ). However, we know that JT4 grows with chronological time during the course of the reaction, and we are obliged to write some form of additional rate equation to express this. Following scheme (XXX),... 

As a first evaluation it might be wise to look just at the basic deactivation results in chronological time. Thus, the four cases are... 

What happens, however, when we translate this to the slurry reactor Now, we also have to make the comparison on the basis of chronological time, but with the holding time I in the reactor as a consideration. Here we have, for example. 

Figure 5.24 (Top) Comparison of the four combinations of deactivation based on chronological time (bottom) comparison based on slurry reactor results. Catalyst 1, + = a of 0.2 h A= a of 0.5 h catalyst 2, O = / of 0.2 h = / of 0.5 h. ...

This comparison is shown on the bottom of Figure 5.24. It is clear in this case that there is no disguise of the superior catalyst by the slurry reactor. Note, though, that the slurry reactor indicates a smaller difference in the performance between Catalyst 1 and Catalyst 2 than might have been expected on the basis of the chronological time comparison. 

At the beginning of our chronological times, Spain had taken over as the main supplier of silver ore and silver metal. Native silver was found, but usually the mined silver was a sulfide mixed with lead sulfide. 

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