Recovery point objective

Recovery Point Objective [RPO] It can be calculated by the point in time where data is restored and reflects the amount of data that will be ultimately lost during the recovery process. The necessary RPO is generally a business decision - for some applications, absolutely no data can be lost [RPO=0], requiring continuous synchronous replication to be used, whereas in other applications, the acceptable data loss could range from a few seconds to hours or even days [4]. 

Figure 18.18 illustrates the shift of the position of the optimum experimental conditions when Pr is replaced by the Pr X Y objective function for the optimization. The maximum production rate is at point A, while Pr x Y reaches its maximum at point B. The contour lines clearly show that the production rate is hardly lower at the new optimum. On the other hand, the recovery yield is improved when the experimental conditions are shifted from point A to point B. The surface determined by Pr x Y exhibits a well defined maximum, which makes the numerical path toward optimization stable. 

In what follows, we describe the interactive solution process for the standard SMB process using the IND-NIMBUS process design tool. For further details, see Hakanen et al. (2007). The aim here is to give an understanding of the nature of an interactive solution process. The DM involved was an expert in SMB processes. First, in the initialization phase, the ranges in the Pareto optimal set were computed as z = (0.891, 0.369, 97.2, 90.0) and = (0.400,2.21, 90.0, 70.0). A neutral compromise solution f(x ) = (0.569,1.58, 92.5,76.9) was the starting point for the interactive solution process. Remember that the objective functions represented throughput (T), consumption of desorbent (D), purity (P) and recovery (R) and their values are here presented in objective vectors in this order (T, D, P, R). Note that the second objective function was minimized while the others were maximized. 

In addition to all of the problems that determine whether the injected mixture of C02 and surfactant solution can perform and survive as a foam in the reservoir rock, the operator of the oil field must design the procedures for injection and other operations in an advantageous way, so that profitability and oil recovery will be maximized. In this pairing of objectives, the oil field s leaseholders and owners are naturally more interested in the best return on their investment than, for instance, in the eventual total recovery. The latter objective, concerned with the overall recovery efficiency, should be the first consideration of the regulating authority. These operational problems entail new factors that transcend those encountered in the laboratory. From the point of view of the operator, the most important considerations are cost and availability of the additional supplies and materials needed, and whether the expected increase in oil production will be more than enough to pay for them. 

Up to this point, we have considered liquids deposited on plates or other large objects. What happens in the case of smaller objects, such as tubes or threads Such questions have direct practical applications. The fact that some residual liquid remains in a tube when one tries to empty it out has important ramifications in the process of assisted recovery of petroleum (when one pumps out a porous rock saturated with oil, approximately 40% of the crude oil is left behind). On a more modest laboratory scale, most of us are familiar with the propensity of a pipette to retain a small amount of liquid after it has been drained out. At the other end of the spectrum, the greasing or oiling of fibers, which refers to their lubrication at high speed, is an important industrial process. It benefits both their manufacture (it cuts back on ruptures by improving their cohesiveness) and their applications (if the fibers are intended to be used as reinforcement of composite materials, the process is used to coat the fibers with adhesion-promoting substances). 

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