Design acceptability limits

Vapor space velocities normally should not exceed 100% of critical experience demonstrates that this keeps liquid entrainment into the flare line within acceptable limits. However, a velocity of 175% of critical is permitted when one is applyingthe 1.5 times Design Pressure Rule to remote contingencies,... 

Mixers are designed to handle a relatively narrow band of incoming product flow rate. Therefore, care must be exercised to ensure that the actual feed rate is maintained within acceptable limits. The O M manuals provided by the vendor will provide the feed-rate limitations for various products. Normally, these rates must be adjusted for viscosity and temperature variations. 

Even with the velocity, turbulence and aeration of the water supplied to the equipment being within acceptable limits, if corrosion is to be avoided it is still necessary for the units themselves to be well designed. Some of the more important aspects involved are outlined below. 

A more subjective approach to the multiresponse optimization of conventional experimental designs was outlined by Derringer and Suich (22). This sequential generation technique weights the responses by means of desirability factors to reduce the multivariate problem to a univariate one which could then be solved by iterative optimization techniques. The use of desirability factors permits the formulator to input the range of property values considered acceptable for each response. The optimization procedure then attempts to determine an optimal point within the acceptable limits of all responses. 

Cold Bent and Formed Piping. The hardness testing method, area of survey, and acceptance limits shall be specified by the material specification and/or the engineering design. 

The next step is to set performance and cost criteria for the system in order to be able to determine whether the new greener design is acceptable. Chelants are often one of the hidden components in a formulation whose value is only found when the system fails. So, what is the cost of batch failure, product spoilage, laundry not being cleaned, reworking in a pulp mill, and so on Also, what is the target cost per dose for the chelant and related chemicals It is important to set acceptable limits on performance - for example, the formulated product needs to be stable for 6 months or show bleach stability >80% over the 30 min wash cycle. 

A flash suppressor, however, can incorporate features that reduce the intensity of the noise. If this type muzzle device can be developed to the point where both flash, and noise can be reduced to acceptable limits, two knotty problems become solved siniultaneousiy. A large amount of effort has been expended on flash suppressors considerably less on noise inhibitors. A measure of success has been achieved in the suppression of noise thru exptn. No general design procedures, either theoretical or empiri-... 

Process control and the associated instrumentation were mentioned in relation to the process selection (Section 3.1). To reiterate those comments, these aspects of plant design must be considered during the process selection stage and at other subsequent stages in the design of the plant. Do not assume that any item of equipment or an entire plant that can be designed can also be operated and controlled efficiently. It should be established early in the design that the control and instrumentation aspects are not only feasible but that the cost is within acceptable limits. 

Classification into groups with acceptable/unacceptable properties Selection of candidates for synthesis Generation of in-house rules or refinement of existing screens for acceptable limits for pharmacokinetic parameters Lead generation Library design... 

The selection of an alloy for a specific application is based on the cost and the corrosion resistance of the alloy in the environment of interest. It is also possible to subject the chosen alloy to a process by which the corrosion resistance of the selected material can be improved within the acceptable limits. Some of the corrosion prevention and protection strategies with respect to the aluminum-based alloys are (i) design (ii) alloy selection and joint sealants (iii) aluminum thermal spraying anodic coatings (iv) inhibitors (v) conversion and organic coatings and (vi) cathodic protection. 

Besides analyzing and correlating data by statistical means, the chemical engineer also uses statistics in the development of quality control to establish acceptable limits of process variables and in the design of laboratory, pilot plant, and process plant (evolutionary operation) experiments. In the latter application, statistical strategy in the design of experiments enables the engineer to set experimental variables at levels that will yield maximum information with a minimum amount of data. 

It may be useful first to consider the minimum acceptable thickness for a film. Although the thinnest films are inherently unlikely to have long lives, there may well be cases in which other design considerations limit the film thickness which can be accommodated. The minimum desirable thickness will obviously depend on the roughness of the substrate and the counterface. Dayson has shown that very thin films increase in friction as film thickness decreases due to an increasing degree of asperity penetration of the film. 

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