Nominal condition

Modify the basic data according to guidelines provided in the handbook, to reflect differences in the assumed "nominal" conditions and the specific conditions for the task being evaluated. The major factor that is taken in to account is the level of stress perceived by the operator when performing the task. 

Aetion limits must be derived from both the specification limits and the charaeteristics of the process they must provide the operators with ample leeway (time, coneentration, temperature, etc.) to react and bring the process back to nominal conditions without danger of the specification limits being exceeded. An important factor, especially in continuous production, is the time constant a slow-to-react process demands narrow action limits relative to the specifieation limits, while many a tightly feed-back controlled process can be run with action limits close to the specifieation limits. If the product conforms to the specifications, but not to the action limits, the technical staff is alerted to look into the potential problem and come up with improvements before a rejection occurs. Generally, action limits will be moved closer to the specification limits as experience accrues. 

Rodriguez LC, Garcia RB, Garcia Campana AM, Bosque Sendra JM (1998) A new approach to a complete robustness test of experimental nominal conditions of chemical testing procedures for internal analytical quality assessment. Chemom Intell Lab Syst 41 57... 

This procedure allows filling pressure in the vehicle tank of 35 MPa to be attained even if the pressure in the low- and medium-pressure storage bank is well below this value. These data are suitable, if the temperature of the gas can be held at 15 °C. Because of the temperature increase during fast fill operation, an overpressurisation is needed to achieve the maximum fill at nominal conditions (35 MPa at 15°C). 

To analyze response surface designs, a model is fitted to the data for each response. Usually the results are visualized in response surface plots, showing the change in response as a function of two factors. " These plots allow deciding on the optimal conditions. However, as already mentioned in Section IV, these response surfaces seem not so useful when only small variations around the nominal conditions are examined. 

To test the factors at three levels in a ruggedness test one usually applies the so-called reflected designs [17,19,23]. A reflected design is in fact a two level Plackett-Burman, full or fractional factorial design that is executed twice. Once the design contains the first extreme and the nominal level and once the other extreme and the nominal level. Both designs have one experiment in common, namely an experiment in which all factors are at nominal conditions. A reflected Plackett-Burman design for 7 factors is shown in Table 3.18. 

Determine the power (per unit length of the shaft) required to operate the pump under nominal conditions. 

Write a simulation program to solve the system, assuming the following nominal conditions The tube radius is rD = 1 cm and the tube length is L — 2 m. The mass flux through the porous wall is characterized by K = 10-4 kg/N. The density and viscosity are constants at p = 0.23 kg/m3 and p = 6 x 10-5 N-s/m2. Wall friction... 

Graph the velocity and pressure profiles for the nominal conditions. Under these circumstances, the pressure should decrease along the length of the tube. Interpret the results in physical terms. 

Solve the plug-flow problem for the nominal conditions and plot the gas-phase concentrations and Si deposition rate as a function of channel position. 

The difficulty with these synthesis methods is that they generate HENs for fixed nominal values of the stream supply temperatures and flow rates and for assumed nominal values of the heat transfer coefficients. In an industrial HEN, the supply temperatures and flow rates will vary (because of unpredictable environmental disturbances or because of predictable feedstock and throughput changes), and the heat transfer coefficients are highly uncertain (due to fouling, etc.). The HEN synthesized for nominal conditions must be resilient (flexible) to changes in supply temperatures and flow rates and to uncertainties in heat transfer coefficients. 

Thermal confinement situations are encountered as nominal conditions in storage and transport of reactive material. The may also happen in failure of production equipment, such as loss of agitation, pump failure, and so on. 

One possible workaround is to reduce quantification tasks to classification problems by defining a number of class representatives for certain concentrations of the analytes. For process control it may be sufficient to define nominal conditions plus a tolerance field as class Acceptable , a wider range as class Warning and everything else as Out of Tolerance . Although this will be only a semi-quantitative analysis with preset readings instead of a classical, continuous calibration, such a solution is sufficient for many process control applications. The reduction into a... 

As presented in the earlier chapters, the operating policy for a batch distillation column can be determined in terms of reflux ratio, product recoveries and vapour boilup rate as a function of time (open-loop control). Under nominal conditions, the optimal operating policy may be specified equivalently in terms of a set-point trajectory for controllers manipulating these inputs. In the presence of uncertainty, these specifications for the optimal operating policy are no longer equivalent and it is important to evaluate and compare their performance. 

U.S. Army Johnston Atoll 3/1/1992 Trial bum, nominal conditions... 

On a more local scale, the effects of turbulence are to impart random motions to particles that are then added to the motions that those particles experience owing to other effects. The details of the resulting motions are beyond the scope of this chapter (comprehensive discussion and equations are provided in Cuzzi Weidenschilling 2006 Ormel Cuzzi 2007). A characteristic velocity that describes these motions is the root-mean-square turbulent velocity, /acs which is the overturn velocity of the largest eddies, and an estimate of the maximum velocity two particles (both of St = 1) would develop with respect to one another (Cuzzi Hogan 2003). Under nominal conditions, such velocities can exceed 100 m s-1 (for a = 0.01). These velocities are important to consider when developing models for dust coagulation and planetesimal formation (see Section 3.4.1 and Chapters 7 and 10). 

The levels selected in a robustness test are different from those at which factors are evaluated in method optimization. For optimization purposes the variables are examined in a broad interval. In robustness testing the levels are much less distant. They represent the (somewhat exaggerated) variations in the values of the variables that could occur when a method is transferred. For instance, in optimization the levels for pH would be several units apart, while in robustness testing the difference could be 0.2 pH units. The levels can for instance be defined based on the uncertainty with which a factor level can be set and re.set 36 and usually they are situated around the method (nominal) conditions if the method specifies pH 4.0, the levels would be 3.9 and 4.1. The experimental designs used are in both situations the same and comprise fractional factorial and Plackett-Burman designs. 

In robustness testing sometimes replicated experiments at the nominal conditions are executed regularly distributed among the design experiments. This allows verifying if the response studied is not affected by time effects, and occasionally to correct for it. 

The effects noted when cracking gas oils of different types agree in general with those observed in work with pure hydrocarbons as feeds. Quantitative comparisons are difficult, however. One of the complicating factors, particularly in fixed-bed comparisons, arises from the fact that, when dissimilar feeds are cracked in admixture, each component is cracked to a different extent than when cracked separately under the same nominal conditions. For example, a hydrocarbon with a low coke-producing tendency cracks to a smaller extent in blends because the other component or components deposit more coke on the catalyst and lower its activity. Although this difficulty can be overcome by specially designed experiments, such data are usually not obtained. 

Finally, the validation work may be performed for this process. This would most likely consist of repeating the 2 full-factorial design mentioned earlier along with three process validation runs at nominal conditions for all factors. The process validation runs would essentially be confirmation runs of the actual process to be used in future commercial manufacturing. Of course, all of these experiments would be based on an approved protocol and would have to yield acceptable data compared with the product specifications. 

Older equipment can require increased maintenance, potentially increasing DPE suit entries that are expensive and not without risk, and more time with the plant in maintenance (off-nominal) conditions. 

A formula for computing the dependent, conditional probability for each dependence level. For a low level of dependence, the formula produces for low values of the independent HEP (i.e. <0.01) a nominal conditional probabihly value of 0.05 with lower and upper bounds of 0.015 and 0.15, respectively (see Table 1). 

---