Kinetic severity factor

As a practical method, designers have employed other methods such as / -pentane conversion as a key component, kinetic severity factor (31), or molecular collision parameter (32) to represent severity. Alternatively, molecular weight of the complete product distribution has been used to define conversion (A) for Hquid feeds. 

The kinetics of the adsorption process are important in detemiining the value and behaviour of. S for any given system. There are several factors that come into play in detemiining S [25]. 

From equation 12.1 it is clear that resolution may be improved either by increasing Afr or by decreasing wa or w-q (Figure 12.9). We can increase Afr by enhancing the interaction of the solutes with the column or by increasing the column s selectivity for one of the solutes. Peak width is a kinetic effect associated with the solute s movement within and between the mobile phase and stationary phase. The effect is governed by several factors that are collectively called column efficiency. Each of these factors is considered in more detail in the following sections. 

These data are typical of lasers and the sorts of samples examined. The actual numbers are not crucial, but they show how the stated energy in a laser can be interpreted as resultant heating in a solid sample. The resulting calculated temperature reached by the sample is certainly too large because of several factors, such as conductivity in the sample, much less than I00% efficiency in converting absorbed photon energy into kinetic energy of ablation, and much less than 100% efficiency in the actual numbers of photons absorbed by the sample from the beam. If the overall efficiency is 1-2%, the ablation temperature becomes about 4000 K. 

Solvent usage is drastically reduced due to several factors. The feed can be flowed through the ChiraLig columns nearly continuously and high feed concentrations can be used as needed. Rapid loading occurs due to reasonable binding kinetics. The subsequent release (elution) step is accomplished in just a few bed volumes, with... 

A wide range of nitroxidcs and derived alkoxyamincs has now been explored for application in NMP. Experimental work and theoretical studies have been carried out to establish structure-property correlations and provide further understanding of the kinetics and mechanism. Important parameters are the value of the activation-deactivation equilibrium constant K and the values of kaa and (Scheme 9.17), the combination disproportionation ratio for the reaction of the nilroxide with Ihe propagating radical (Section 9.3.6.3) and the intrinsic stability of the nitroxide and the alkoxyamine under the polymerization conditions (Section 9.3.6.4). The values of K, k3Cl and ktieact are influenced by several factors.11-1 "7-"9 ... 

Definition of a method for obtaining samples for a source of kinetic data on this reactive extmsion must take several factors into account o Extremely small initiator to polymer ratios are involved, o The rate of dispersion of the initiator and the degree of dispersion obtained is likely itiq>ortant to both the homogeneity of the product and the efficiency of the initiator. 

However, the pattern is complicated by several factors. The sugar molecules to be hydrogenated mutarotate in aqueous solutions thus coexisting as acyclic aldehydes and ketoses and as cyclic pyranoses and furanoses and reaction kinetics are complicated and involve side reactions, such as isomerization, hydrolysis, and oxidative dehydrogenation reactions. Moreover, catalysts deactivate and external and internal mass transfer limitations interfere with the kinetics, particularly under industrial circumstances. 

There are several factors through which anions can influence the pathway and O2 reduction kinetics. The main factors are competition with O2 for surface sites changes in the activity coefficients of the reactants, intermediates, and transition states and the acidity and dielectric properties of the electrolyte side of the interface [Adzic, 1998]. For example, perfluoro acids have higher O2 solubility and lower adsorbability than... 

There are several factors that may be invoked to explain the discrepancy between predicted and measured results, but the discrepancy highlights the necessity for good pilot plant scale data to properly design these types of reactors. Obviously, the reaction does not involve simple first-order kinetics or equimolal counterdiffusion. The fact that the catalyst activity varies significantly with time on-stream and some carbon deposition is observed indicates that perhaps the coke residues within the catalyst may have effects like those to be discussed in Section 12.3.3. Consult the original article for further discussion of the nonisothermal catalyst pellet problem. 

The pressure drops throughout the cyclone owing to several factors (1) gas expansion, (2) vortex formation, (3) friction loss, and (4) changes in kinetic energy. The total pressure drop can be expressed in terms of an equivalent... 

Quantitative fits of the rate constant to concentrations of surfactant or reagent are sometimes poor when [surfactant] is close to the cmc. Several factors can be involved here (l) the kinetic cmc can be lower than that in water because the reagents promote micellization (ii) reaction is promoted by submicellar aggregates or (iff) the simplifying assumptions involved in the kinetic equations (2-6) may be invalid when concentrations of substrate and micellized surfactant are similar (Romsted, 1984). 

An electron impact (El) ion source uses an electron beam, usually generated from a rhenium filament, to ionize gas-phase atoms or molecules. Electrons from the beam (usually 70 eV) knock an electron from a bond of the atoms or molecules creating fragments and molecular ions [366,534,535]. Several factors contribute to the popularity of El ionization in environmental analyses such as stability, ease of operation, simple construction, precise beam intensity control, relatively high efficiency of ionization, and narrow kinetic energy spread of the ions formed. 

The kinetics of the Grignard reaction was recognized to be much more complex than originally considered because of several factors the Schlenk equilibrium produces many reacting species, a metal impurity induces an ET process, and the primary product, ROMgX, contributes to the reaction . 

Having generated suitable (partially) cationic, Lewis acidic metal centers, several factors need to be considered to understand the progress of the alkene polymerisation reaction the coordination of the monomer, and the role (if any) of the counteranion on catalyst activity and, possibly, on the stereoselectivity of monomer enchainment. Since in d° metal systems there is no back-bonding, the formation of alkene complexes relies entirely on the rather weak donor properties of these ligands. In catalytic systems complexes of the type [L2M(R) (alkene)] cannot be detected and constitute structures more closely related to the transition state rather than intermediates or resting states. Information about metal-alkene interactions, bond distances and energetics comes from model studies and a combination of spectroscopic and kinetic techniques. 

When we try to do this, we quickly find that the predicted patterns of kinetic stability depend on several factors ... 

This chapter describes the different types of batch and continuous bioreactors. The basic reactor concepts are described as well as the respective basic bioreactors design equations. The comparison of enzyme reactors is performed taking into account the enzyme kinetics. The modelhng and design of real reactors is discussed based on the several factors which influence their performance the immobilized biocatalyst kinetics, the external and internal mass transfer effects, the axial dispersion effects, and the operational stabihty of the immobilized biocatalyst. 

The design equations described in the last section are only valid for ideal reactions when the reactions are kinetically controlled. However, the modelling of enzyme reactions should take into account several factors which influence their performance. These factors are ... 

So, it seems that there exists a discrepancy about the mechanism of polymerization. Until this is resolved the proposed mechanism of the reaction must be in doubt. Therefore, we have realized a systematic study (UV, NMR, kinetic) of the influence of several factors determining the reactivity of active centres in the case of the polymerization of isoprene (17, 18, 19). 

Several factors have contributed to this goal in the recent past development of electrochemical techniques for the study of complex reactions at solid electrodes, use of physical methods such as ESCA, Auger, LEED, etc. for the study of surfaces in the ultrahigh vacuum (UHV) environment and in situ techniques under the same conditions as the electrode reaction. Ellipsometry, electroreflectance, Mossbauer, enhanced Raman, infrared, electron spin resonance (ESR) spectroscopies and measurement of surface resistance and local changes of pH at surfaces were incorporated to the study of electrode kinetics. 

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