Process sensitivity

Davis, G.D. and Kolonko, L.L., Process control methodology — process sensitivity evaluation of the case to insulation bondline. In Proc. JANNAF Structure and Mechanical Behavior Subcommittee Meeting, Pub . 591. Chemical Propulsion Information Agency, Columbia, MD, 1992, p. 67. 

Establishing the process sensitivity with respect to the above-mentioned factors is crucial for further scale-up considerations. If the sensitivity is low, a direct volume scale-up is allowed and the use of standard batch reactor configurations is permitted. However, many reactions are characterized by a large thermal effect and many molecules are very sensitive to process conditions on molecular scale (pH, temperature, concentrations, etc.). Such processes are much more difficult to scale up. Mixing can then become a very important factor influencing reactor performance for reactions where mixing times and reaction times are comparable, micromixing also becomes important. 

In the low-energy range a depends on the defect density, doping level, and details of the preparation process. Sensitive subbandgap spectroscopy is used to measure a and relate it to the defect density in the material [78, 79]. 

The third process sensitive to heavy-atom perturbation is the radiative decay from the triplet to the ground state (phosphorescence). Since phosphorescence is commonly not observed in fluid solution at room temperature, the rate of phosphorescence in the presence of heavy-atom perturbation relative to the rate of intersystem crossing and nonradiative decay need not be considered. At low temperatures in a rigid glass, however, phosphorescence... 

In addition, many other aspects must be considered when developing a catalytic reaction for industrial use these include catalyst separation, stability and poisoning, handling problems, space-time yield, process sensitivity and robustness, toxicity of metals and reagent, and safety aspects, as well as the need for high-pressure equipment. 

Ionizing Air for Static Charge Neutralization While Processing Sensitive Materials... 

The amorphous phase is not usually a desirable state for the API because the formation process is more random and difficult to control than a crystallization. A second dispersed liquid phase is usually formed just prior to freezing and may coalesce or disperse under the influence of hydrodynamic forces in the crystallizer, making the process sensitive to micro-mixing effects on scale up. Amorphous solids also have significantly lower thermodynamic stability than related crystalline material and may subsequently crystallize during formulation and storage. Because of the non-uniformity of the amorphous solid it can more easily incorporate molecules other than the API, making purification less effective. 

Carty R, Cox K, Punk J, Soliman M, Conger W (1977) Process sensitivity studies of the Westinghouse sulfur cycle... 

KINPTR simulations of commercial reforming (Table XVIII) will be used in this section to demonstrate process sensitivity. In the base case, a full-range Mid-Continent naphtha (55 wt. % paraffins) is reformed to a constant octane of 90 R + 0 over the entire cycle. With a reactor pressure of 1695 kPa and a 7.2 H2 recycle ratio, the start-of-cycle reactor inlet temperature to achieve target octane is predicted to be 759 K. The deactivation simulation shows that it would take about 1 year to reach the end-of-cycle temperature of about 798 K. The start-of-cycle C5+ yield for this case is 86 vol %. The model predicts that the yield would decline by 4.8 vol % over the cycle. 

The critical problem of sample size and the limitations imposed thereby on the accuracy of elemental analyses, especially those for carbon and hydrogen, suggest the application of chromatographic techniques. Amino acid analysis may provide a superior method of assessing collagen loss with additional information regarding the selective decomposition processes, sensitive to local soil conditions. 

Pipelines and equipment are mostly resistance processes. When the flow is turbulent, the resistance is a function of the square root of pressure drop. A change in flow results in an immediate and proportional change in pressure drop. The amount of change is a function of the process gain, also called process sensitivity. 

The constituent properties from Table 1.3 can, in turn, be used to simulate the stress-strain curves (Fig. 1.31). The agreement with measurements affirms the simulation capability whenever the constituent properties have been obtained from completely independent tests (Table 1.1). This has been done for the SiC/CAS material, but not yet for SiC/SiC. While the limited comparison between simulation and experiment is encouraging, an unresolved problem concerns the predictability of the saturation stress, crs. In most cases, ab initio determination cannot be expected, because the flaw parameters for the matrix (processing sensitive. Reliance must therefore be placed on experimental measurements, which are rationalized, post facto. Further research is needed to establish whether formalisms can be generated from the theoretical results which provide useful bounds on as. A related issue concerns the necessity for matrix crack density information. Again, additional insight is needed to establish meaningful bounds. Meanwhile, experimental methods that provide crack density information in an... 

Polymer synthesis is a very particular process, sensitive even to slight variations of both chemical and physical parameters. It would probably be impossible to produce a good quality polymer by purely empirical methods, or else the development of the technology would be very expensive. On the other hand, if every production phase should have to be supported by scientific understanding, such production could never be started. Therefore only a reasonable proportion of scientifically supported facts and suitable empirical procedures leads to technologically feasible results. Unfortunately we have no recipe for determining the sufficient amount of scientific data necessary for the realization of an important technological development. 

Nearly all types of coating processes will benefit from a consistent process air dew point. Humidity control systems may be complex, incorporating dehumidifiers (for dew point reduction to about 5-iO C). desiccant dryers (for products requiring low product temperatures and dew points below 0 C), steam humidifiers (to increase dew point in cold, dry weather), etc. It is suggested that laboratory trials be conducted to evaluate product and process sensitivity to variations in inlet air dew point. 

For most other aspects such as catalyst stability and sensitivity, handling problems, catalyst separation, space-time yield, poisoning, chemoselectivity, process sensitivity, toxicity, safety, special equipment, etc., enantioselective catalysts have similar problems and requirements compared to nonehiral homogeneous catalysts. 

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