Overall or integral

Secondly, selectivity can be defined with reference to another product. Overall or integrated selectivity is the ratio of the amount of one product (B) produced to the amount of another (C). For example, for reactions... 

As discussed in Chapters 2 and 3, in the integral method it is assumed that the boundary layer has a definite thickness and the overall or integrated momentum and thermal energy balances across the boundary layer are considered. In the case of flow over a body in a porous medium, if the Darcy assumptions are used, there is, as discussed before, no velocity boundary layer, the velocity parallel to the surface near the surface being essentially equal to the surface velocity given by the potential flow solution. For flow over a body in a porous medium, therefore, only the energy integral equation need be considered. This equation was shown in Chapter 2 to be ... 

A complex system is one in which more than one reaction occurs. This can lead to ijiultiple products, some of which are more desirable than others from a practical standpoint. For example, in the air oxidation of ethylene the desired product is ethylene oxide, but complete oxidation to carbon -dioxide and—water—alse-0eeu-FS--The-im-perta-nt-per-for-ma-nee-factor-is-i he production rate of ethylene oxide and its purity in the reaction products, rather than the total amount of ethylene reacted. To characterize this performance two parameters are used yield and selectivity. The yield of a specific product is defined as the fraction of reactant converted to that product. The point selectivity is the ratio of the rate of production of one product to the rate for another product. With multiple products there is a separate selectivity based on each pair of products. The overall, or integrated, selectivity is the ratio of the amount of one product produced to the amount of another. Selectivity and yield are related to each other through the total conversion, i.e., the total fraction of reactant converted to all products. 

Measures of Global Accuracy of Performance Measures of global (or overall or integrated) sensory-motor control capacities have proven invaluable for ... 

Measures of global (or overall or integrated) accuracy of performance. 

For an overall or integrated change across the membrane between the liquid reject phase and the liquid permeate phase, it follows that, in consistent units. 

It must be emphasized that it is not worth expending any effort optimizing pressure, feed condition, or reflux ratio until the overall heat-integration picture has been established. These parameters very often change later in the design. 

In heterogeneous systems AP must be critically reviewed, especially if the reaction involves a two-phase mixture of liquid and gas, or if the gas flows through a deep bed of catalyst particles as in the FCC systems. AP should be checked early in the design process to assess its influence on the overall plant integrity. 

It is important to remember that unexpected benefits may arise from integration. You should actively look for these benefits and document them. It may be possible to improve some of these benefits by small modifications to the plan or integration framework. Such additional work should be undertaken only with the appropriate approvals. Never the less, if any benefits would only be achieved with the integration project, you should include them in your overall statement of benefits. An example of this might be the better allocation of capital to risk reduction efforts when an integrated risk assessment is done-addressing several different types of risk. 

As complex as the regulation of carbohydrate metabolism is, it is far from the whole story of fuel metabolism. The metabolism of fats and fatty acids is very closely tied to that of carbohydrates. Hormonal signals such as insulin and changes in diet or exercise are equally important in regulating fat metabolism and integrating it with that of carbohydrates. We shall return to this overall metabolic integration in mammals in Chapter 23,... 

A control strategy hope lly can then be evolved. It is also necessary to determine the ancillary instruments required for process monitoring, and for plant commissioning and start-up. It is worthwhile at the design stage including connections for instruments which may be required in the future. The location (local or a distant control room) and types of recorders must be specified, and the alarms and interlocks that are required. Control does not occur independently in different units, and an overall and integrated approach to the control of the plant is required. 

In order to compare the economics as well as the overall C02 emissions from each schematic studied in this joint venture, a reference case was analyzed. The reference case included only the process steps associated with coal gasification, shift, and hydrogen purification, but none of the steps associated with C02 sequestration or coalbed methane recovery. Three other process schemes were examined in this study and compared to the reference case. Figure 1 depicts simplified process flow diagrams for the reference case and the other three schemes (note the overall heat integration for each scheme is not shown). The top portion of the figure shows the process steps that are the same for each scheme up to hydrogen purification, while the operations inside the dashed boxes represent the steps that differ between the four cases. 

We distinguish integral and differential characteristics of catalytic properties. One of the integral characteristics is the extent of reaction Generally, any chemical reaction, whether overall or an elementary step, can be represented by a stoichiometric equation ... 

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