Effects of internal and external

Figure 9. Effects of internal and external transport resistances on the computed step-response of CO adsorption. Curve A corresponds to our experimental conditions. Key A, km = 60 cm/s, Deff = 0.0246 cm2/s B, km —r oo, Detl = 0.246 cms/s and C, km — oo, Dell oo.

The expression for the effectiveness factor q in the case of zero-order kinetics, described by the Michaelis-Menten equation (Eq. 8) at high substrate concentration, can also be analytically solved. Two solutions were combined by Kobayashi et al. to give an approximate empirical expression for the effectiveness factor q [9]. A more detailed discussion on the effects of internal and external mass transfer resistance on the enzyme kinetics of a Michaelis-Menten type can be found elsewhere [10,11]. 

Hatfield, B. and Aris, R. (1969). Communications on the theory of diffusion and reaction, part (iv), combined effects of internal and external diffusion in the non-isothermal case. Chem. Eng. Sci., 24, 1213-22. 

Greenaway, P. Calcium regulation in the freshwater mollusc Limnea stagnalis. 1. The effect of internal and external calcium concentration. J. exp. Biol. 54, 199 (1971)... 

In Section V-D it was shown that Slurry sensitivity and performance depend on Slurry characteristics such as d, particle size of solids and compn, as well as external factors such as pressure and temp. To a considerable degree the effects of internal and external factors can be optimized by control of the rheology and d of Slurries. We shall now examine the rationale behind these control methods... 

Summary of Effects of Internal and External Mechanical Forces... 

Konovalov, A. I., Kiselev, V. D. Diels-Alder reaction. Effect of internal and external factors on the reactivity of diene-dienophile systems. Russ. Chem. Bull. 2003, 52, 293-311. 

The differential equations involve the effective diffusivity and thermal conductivity of the porous pellet. Data and theories for these quantities are given in Secs. 11-1 to 11-5, and in Secs. 11-6 to 11-11 the results are used to establish the rate for the whole pellet. The method of combining the effects of internal and external transport resistance to give the global rate in terms of bulk fluid properties is discussed in Chap. 12. 

We emphasize first of all that the disorder in the subsurface region, i.e. in the region of localization of the surface exciton, may result from its own internal disorder or may be caused by other, external reasons (e.g. by absorbed molecules). The microscopic surface states under consideration are strongly affected by both types of disorder. This circumstance should be borne in mind even in the cases when SSSE are treated in isotopically disordered crystalline solutions. In such states, which interact weakly with internal crystal monolayers, the effect of internal and external disorder can result in equally serious consequences. We will now make some qualitative remarks on the Anderson localization of surface excitons. As before let us assume a molecular crystal, ignore the exciton-phonon interaction, but take into account, for instance, the diagonal disorder (i.e. the random energy distribution of molecular excitations). 

The effect of pH changes on the potency of local anesthetics has been extensively investigated (30). Based on these studies, it was concluded that local anesthetics block the action potential by first penetrating the nerve membrane in their un-ionized forms and then binding to a site within the channels in their onium forms. Perhaps the most direct support for this hypothesis comes from the experimental results of Narahashi et al. (31,32), who studied the effects of internal and external perfusion of local anesthetics (both tertiary amines and quaternary ammonium compounds), at different pH values, on the sodium conductance of the squid axon. The observation that both tertiary amines and quaternary ammonium compounds produce greater nerve blockage when applied internally indicates an axoplasmic site for these compounds. 

Tasaki I, Singer I, Takenaka T. Effects of internal and external ionic environment on excitability of squid giant axon. A macromolecular approach. J Gen Physiol... 

Consider the volume element between r and r + dr, as shown in Figure 4.6. Assume a simple first-order irreversible reaction, and assume the temperature is uniform so that and k are constant. The effect of internal and external temperature gradients is discussed in the next chapter. 

Stability and stabilization of enzymes. Elsevier, Amsterdam, pp 111-131 Munro PA, Dunnill P, LiUy MD (1981) Casein hydrolysis in a stirred tank reactor using chy-motrypsin immobilized on magnetic supports. Biotechnol Bioeng 17(10) 1515-1528 Naik S, Karanth N (1978) Effect of internal and external diffusion on the apparent stabiUty of immobUised enzyme catalysts. J Appl Chem Biotechnol 28 569-580 O Fagain C (2003) Enzyme stabilization - recent experimental progress. Enzyme Microb Technol 33 137 149... 

The construction may have a single measuring system, or a twin or differential measuring system. Simple solution calorimeters have a single cell, while a DSC has twin cells and operates in the scanning mode. The use of twin cells reduces the effects of internal and external noise and transient fluctuations. 

Thus far we have considered the two effects of internal and external diffusion separately. The combined effects can be accounted for as follows. 

Chapter 7 Catalysis by Solids, 2 The Catalyst and Its Microenvironment, 171 Modeling of Solid Catalyzed Reactions, 171 Role of Diffusion in Pellets Catalyst Effectiveness, 183 Effect of External Mass and Heat Transfer, 201 Combined Effects of Internal and External Diffusion, 204 Relative Roles of Mass and Heat Transfer in Internal and External Diffusion, 205 Regimes of Control, 206... 

Table 8 Data on the effect of internal and external donOTs on Cp and kp values fw propylene polymerization [183,187, 188] (SF method)...

In calculating the effects of internal and external loadings, due account was taken of the creep properties of the visco-elastic HOPE selected. The design life was 50 years. Examples are given in sections 7 and 8 of the calculations necessary to ensure a 50 year life in the installation. 

The acceptance criterion for the resolution of GSI A-29, is that plants shall be designed to be resistant to the effects of internal and external sabotage through prevention, deterrence, and mitigation. 

Ti- Sq to external spinorbit perturbation. Maximum enhancements of 980 and of 136 were observed in the dimethyl and tetramethyl compounds. The influence of oxygen on is given in Figure 11. For a series of three derivatives of 10,10 dimethyl biacridan we have compared the effect of internal and external spinorbit coupling perturbation. The results are reported in Table I. Internal perturbation is achieved by tetrabromo substitution while external perturbation is introduced by oxygen at a concentration of 1.1 x 10 M. The internal perturbation results in a 100 fold increase of while external perturbation has an effect varying from 220 in the first compound to 2 in the tetrabromo derivative. 

Adrian, R. H., 1956, The effect of internal and external potassium concentration on the membrane potentials in frog muscle, J. Physiol. 133 631-658. 

This case happens if the coefficient of external mass transfer kg is considerably large and the catalyst particles are smaller i.e., the effects of internal and external diffusion have been eliminated. 

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