Recovery time objective

Recovery Time Objective [RTO] It can be calculated by the amount of time between an outage and the restoration of operations. RTO is also dependent on the various techniques used for the backup and type of application this may involve additional manual steps such as verifying the integrity of state or performing application, restoring of data operations, and scheduling of recovery tasks to be done efficiently [4]. 

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]. 

Optimal control of a batch distillation column consists in the determination of the suitable reflux policy with respect to a particular objective function (e.g. profit) and set of constraints. In the purpose of the present work, the optimisation problem is defined with an operating time objective function and purity constraints set on the recovery ratio (90%) and on the propylene glycol final purity (80% molar). Different basis fimctions have been adopted for the control vector parameterisation of the problem piecewise constant and linear, hyperbolic tangent function. Optimal reflux profiles are determined with the final conditions of the previous optimal reactions as initial conditions. The optimal profiles of the resultant distillations are presented on figure 2. 

The presence of an independent safety system can limit the dependability needs of the nominal set to the requirements relative to the mission (tolerance to one fault, a goal of 99% for docking and 95% for the entire mission). Thus each piece of avionics equipment is organized in a conventional redundancy scheme (a unit in cold redundancy except for critical elements, fallible, or with long recovery time). However, unlike traditional solutions in satellites, given the objectives of continuity of service, a set of three computers in hot redundancy is used with comparison and voters distributed in each computer (to avoid failure on loss of a single centralized voter), in addition to mechanisms of error detection within each computer. 

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

U.S. EPA defines MNA as the reliance on natural processes, within the context of a carefully controlled and monitored site cleanup approach, to achieve site-specific remediation objectives within a time frame that is reasonable compared to that offered by other more active methods. The natural processes include biodegradation, dispersion, dilution, sorption, volatilization, stabilization, and transformation. These processes reduce site risk by transforming contaminants to less toxic forms, reducing contaminant concentrations, and reducing contaminant mobility and bioavailability. Other terms for natural attenuation in the literature include intrinsic remediation, intrinsic bio-remediation, passive bioremediation natural recovery, and natural assimilation. 30... 

Paradoxically, one of the most reliable indications of recovery is the return of awareness by the subject that he is not as proficient as he should be. Subjects who receive an incapacitating dose usually regain this awareness by the third or fourth day. By this time, their objective performance on addition and word recognition tests has generally risen to 80 or 90 percent of their baseline level, and the principal symptoms are some residual lassitude and blurring of vision.. 

The abnormal appearance of the skin mentioned by one subject, as well as his attempt to rub blood off his fellow test subject, was also reported by other volunteers. For some reason, never explained, those who received high doses of glycolates often saw red coloration on their skin and other objects. Sometimes, at the sink, they even thought they were washing blood from their hands. This visual disturbance was always temporary, and disappeared by the time of recovery. 

Previously published civilian studies of drug effects on performance over time did not give this problem much consideration, and usually included only 1-3 practice trials. In some cases, improvement by the time of recovery was indeed evident, but for the investigators it was usually not a matter of great concern since the objectives of their studies were usually limited to showing a statistically significant rather than a precise degree of impairment. 

Thus with given B0m and V, specification of the set of operations decision variables D°m = d°j, i = 1, NTm] (a total of 2 NTm decision variables) and control variables Um = t-, i = 1,NTm for all distillation tasks in operation m, it will be possible to calculate the overall performance measures for the batch (total distillation time, overall separation, products and intermediates amounts, recoveries, energy, etc.)- The same decision variables may be optimised to achieve some overall objective for the operation, (e.g. overall profit) subject to overall constraints (e.g. overall time, energy, etc.). 

Comparison of the results in Table 7.9 with those in Table 7.7 (and Table 7.8) and Table 7.4 show significant differences in the design, operating policies, optimal recoveries of products, number of batches to be processed for each duty and total yearly profit. This clearly shows the importance of including allocation time and set up time between batches in the objective function. It is to be noted that in all cases a simple model but detailed plate-to-plate calculations (Type HI) with reasonable column holdup is used (unlike a short-cut model ignoring column holdup as in Logsdon et al.). 

Also Mujtaba (1997) considered the separation of binary mixtures into one distillate product of specified purity. The objectives were to find out whether it was possible to replace conventional dynamic operation of batch columns by steady state operation using continuous columns for a comparable recovery, energy consumption, operation time, productivity, etc. and to obtain optimal operating policy in terms of reflux ratio. The following strategy was considered to compare the performances of the two types of operations ... 

Comparison with CBD operation The dynamic optimisation problem is solved with a batch time of 3.685 hr (equal to the total operation time of the multi-pass case of Table 11.4). The objective is to maximise the amount of distillate (or recovery) with a purity of 0.90 molefraction in component 1. 

The results mostly show that the optimiser has been able to adjust the reflux and reboil ratios and the distillation time in such a way as to increase the total amount collected (i.e., the objective function), the capacity factor (productivity). Greaves et al. (2003) included another performance index (%Recovery of key component) in addition to CAP and the conclusions remained the same. 

In cases where mass transfer is rapid, as is the case with most small molecule separations, then isocratic elution can offer advantages such as automatic fraction reprocessing and solvent recycle. However, with larger synthetic objectives the rate of mass transfer is comparatively low so isocratic elution leads to band broadening and subsequently to recovery of the peptide at high dilution. Most preparative HPLC based peptide separations are carried out under gradient and overload conditions that allow for maximum throughput in terms of time and quantity. 

The success of a particular analytical or preparative HPLC strategy with polypeptides or proteins is predicated by the ease of resolving to a predefined level the desired component from other substances, many of which may exhibit similar separation selectivities but are usually present at different abundance levels. For high-resolution purification procedures to be carried out efficiently, it is self-evident that rapid, multistage, high-recovery methods must be utilized. To minimize losses and improve productivity, on-line, real-time evaluation of each of the recovery stages is an essential objective. Furthermore, overall optimization and automation of the individual unit operations must be achieved. Similar criteria but with different endpoints apply in high-resolution analytical application. 

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