Reactivity approach

As a process analytical solution, these extrinsic reactive approaches necessitate an extrinsic optode (see later discussion), an on-line sample conditioning system or an at-Une solution such as a flow injection analysis (FIA) system or other autonomous solutions. Reaction kinetics, post analysis cleanup such as rejuvenating a substrate (optode, immobilized based immunoassays, etc.) among other complexities are additional considerations for these types real-time analysis methods. ... 

The application of reactivity approaches to consumer products is discussed in detail by Dimitriades (1996). 

M 71 ] [P 64] Flow cross-sectional images were taken in the 3-D L-shaped micro mixer using a reactive approach to characterize mixing [153], Initially, a bi-laminated system is observed, then the interface becomes more and more stretched and elongated, and finally the streams intertwine deeply and mixing results from this... 

M 81] [P 70] A microscopy-image analysis of the color formation due to a reactive approach reveals that the micro mixer with helical elements and barriers gives a better performance than the micro mixer with helical elements but without barriers and a reference pipe structure without either helical elements or barriers (see Figure 1.167) [3], The pipe gives the expected profile with two colorless fluid compartments on top and at bottom, separated by a colored interface. This is indicative of the absence of any swirling, secondary flow. 

Mixing was characterized by dilution-type imaging using ink and pure water solutions [56], As a reactive approach, color imaging was performed by a pH-indicator reaction, merging phenolphthalein solution (0.01 M in water-ethanol) and aqueous NaOH solution (0.3 M). 

D. Price, K. Pyrah, T.R. Huh, G.J. Milnes, J.R. Ebdon, BJ. Hunt, P. Joseph, and C.S. Konkel, Flame retarding poly(methyl methacrylate) with phosphorus-containing compounds Comparison of an additive with a reactive approach. Polym. Degrad. Stab., 74,441 447 (2001). 

Ebdon, J. R., Hunt, B. J., Joseph, P., and Konkel, C. S., Flame-retarding thermoplastics Additive versus reactive approach, in Speciality Polymer Additives Principles and Applications, Al-Malaika, S., Golvoy, A., and Wilkie, C. A. (Eds.), 2001, Blackwell Science, Oxford, U.K., pp. 231-257. 

The reactive approach has been employed recently to prepare various polymeric systems.34 35 Silicon-containing polystyrenes and poly(methyl methacrylate)s (PMMAs) copolymers have been prepared by free radical polymerization. The LOI data indicated that a marginal improvement in flame retardancy has been observed compared to the parent homopolymers. The authors speculated that the nature of the silicon-containing group has an effect on the flame-retardant mechanism.34... 

If uncertainty is not in the range of the proactive model scenarios (Table 2), the reactive approach gives better evaluation criterion values in all cases. The last scenario in Table 2 is an extreme case and demonstrates the superiority of the reactive model (a 67,5% better) if the uncertainty takes place very close to the end of time horizon (Fig. 1). 

In this work, a comparison between proactive and reactive approaches has been carried out in terms of a new proposed evaluation criterion that considers earliness and tardiness, as well as rescheduling costs. This cost takes into account the total deviation from initial starting times and a batch reallocation cost which is proportional to the objective function. According to the presented case studies, the further from initially considered values uncertainty unveils, the better the reactive schedule performs according to the evaluation criterion. On the contrary, if uncertainty unveils as forecasted, and early in the time horizon, the best choice is the proactive approach. Future work will be focused on the validation and further improvement of the proactive-reactive control scheme. 

In the previous section, we have seen how the presence of a -CH3 group has a strong influence on the chemistry of CN addition to a triple acetylenic bond. In this section we further explore such an effect by moving to the fully CH3-substituted species, dimethylacetylene. Also, in this case, we expect a similar reactive approach with the cyano radical attacking the n-orbital of the dimethylacetylene molecule. The possible reaction routes are (Figure 14.10)... 

As seen in Table 1, the required heat per carbon atom is less for normal heptane than for methane. It means that the fired duty in the tubular reformer will be slightly less when operating at similar conditions on naphtha instead of natural gas. The higher hydrocarbons are also more reactive than methane with aromatics showing the lowest reactivity approaching that of methane. 

Fukui calculations for Cpd 1 are in line with experimental and theoretical evidence. Development of a combined docking/local reactivity approach could be a less reliable, but significantly cheaper, alternative to QM/MM studies on full reaction paths. 

In 1990 our understanding of the underlying causes of risk were challenged with the publication of Janies Reason s Human Error [8], For the first time the role of human factors in the incident causality chain were truly characterised. He eloquently made the case for adverse events being a function not of personal inadequacies but of the environment in which individuals operate. This paved the way for transforming a largely reactive approach to risk management in healthcare to one of hazard identification and proactive risk control. 

The definition of reactivity inferred from measurements depends both on the type of integral parameter measured and on the procedure adopted for transforming the measured parameter into reactivity. Four definitions of reactivities have been presented in this section. As the reactor approaches criticality, the four reactivities approach the same value. The further the reactor is from criticality (or the larger the alteration of the system), the greater the difference in the value of the various reactivities. 

Functionality (chemical reactivity approach) and atom economy (green chemistry approach) are the driving criteria of this assessment, which is developed from a strictly chemical point of view. Ultimately, the applications of the product need to be considered, next to the existence of drop-in or rising potential markets as well as technological measures. 

The influence of phosphorus incorporated through a reactive approach on the flame retardancy of polymers is reviewed in Chapter 12 by Sonnier et al. It is notably demonstrated that phosphorus has an influence on the degradation pathway of the polymer and hence its thermal stability and charring. 

The choice of optimal synergistic combination depends on the base polymer and halogen source used. That is additive vs. reactive approach and aromatic vs. aliphatic halogen source. 

At the highest strategic level, an organization can adopt either a proactive or a reactive approach toward product development. Which is appropriate depends on growth opportunities, protection for innovation, market scale, competition, and position in production and distribution system (Urban and Hauser, 1993). Since the Internet offers the potential to change these, one possible research question is how the advent of e-commerce may alter decisions about product development strategy (e.g., does it become more or less important to offer a stream of innovative new products as the web increases in importance as a marketing channel )... 

Figure 3-5. A reactive approach for deriving preventive actions from accidents.

A reactive approach can be used to develop strategies for preventing accidents. Figure 3-5 illustrates how that... 

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