摘要:

AbstractEquilibria of reactions catalyzed by acetate kinase and adenylate kinase were studied experimentally and theoretically. Nucleotide conversions in excess of 90% were obtained with reactants (acetyl phosphate and one nucleotide) in stoichiometric proportion for ATP regeneration from either ADP via acetate kinase or AMP via the coupled enzyme system. Observed equilibrium constants, measured as a function of [Mg2+] atpH 7.4, ranged from about 1 to 9 for the reaction catalyzed by adenylate kinase and from about 50 to 400 for the reaction catalyzed by acetate kinase. These results agreed well with prediction of a theoretical model for the multiple equilibria between all species present in solution. Theoretical calculations showed that magnesium ion complexes and totally dissociated anions are the predominant species in solution at\documentclass{article}\pagestyle{empty}\begin{document}$p{\rm H}\tilde>7{\rm and}[{\rm Mg}^{2 + } ]\tilde>10^{ - 3} {\rm M}$\end{document}.

ISSN:0001-1541    

DOI:10.1002/aic.690230102

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractA correlating equation for assisting convection was developed by combining correlating equations for pure free and pure forced convection. These component equations are based on laminar boundary‐layer theory for an isothermal, vertical plate. Theoretical values for assisting convection indicate that the third root of the sum of the third powers gives the best representation, as contrasted with the choice and rationalization of the second or fourth power by prior investigators.This expression was modified by the addition of a limiting valueNuoto obtain a better representation below the domain of boundary‐layer theory and was generalized for uniform heating and for spheres and horizontal cylinders by the appropriate choice of the characteristic len

ISSN:0001-1541    

DOI:10.1002/aic.690230103

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractThe film theory for gas absorption with chemical reaction has been extended to take into account the release of heat due to solution and reaction. The analysis is applied to the industrially significant sulfur trioxide‐dodecylbenzene system, and large increases in interface temperature are predicted during absorption. The enhancement factor behavior is correspondingly complex owing to the interaction of solubility reduction and rate constant enlargement. Some initial experimental measurements with the laminar jet technique confirm the need for and the basic soundness of the theor

ISSN:0001-1541    

DOI:10.1002/aic.690230104

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractSpin line tension, diameter attenuation, and the onset of the draw resonance instability are determined for a viscoelastic polymer melt, taking into account the changes in physical properties resulting from cooling of the filament. The theory predicts the experimentally observed stabilization of very short and very long filaments.

ISSN:0001-1541    

DOI:10.1002/aic.690230105

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractNew measurements are presented on the influence of Schmidt number on the rate of mass transfer between a turbulent fluid and a pipe wall. It is found that for large Schmidt numbers the fully developed mass transfer coefficient is related to the friction velocity and the Schmidt number by the equationThe experiments are accurate enough to rule out theSc−2/3or theSc−2/3relations commonly used, deduced from plausible limiting expressions for the eddy diffusivity close to a wall. It is argued that these expressions arevalid only over a vanishingly small portion of the concentration field asSc

ISSN:0001-1541    

DOI:10.1002/aic.690230106

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractPerformance of flush drains in gas‐liquid separators has been evaluated under conditions of variable gas flow and pressure, liquid height and flow rate, and drain diameter. For the two‐phase flow regime, liquid flow rate is found to be independent of vessel pressure or gas flow rate. Transition from weir control to orifice control of liquid flow rate occurs over the range ofH/Dratios from 0.4 to 1.5. In this range, simple orifice equations do not apply. Revised design equations for use to determine minimum liquid height for maintenance of single‐phase downflow in gas‐liquid separators are pr

ISSN:0001-1541    

DOI:10.1002/aic.690230107

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractThe response of a fixed bed of porous particles through which fluid flows to a pulse of tracer gas has been analyzed by a number of methods. It is found that analysis of the Fourier transformed and the Laplace transformed response curves for small values of the parameters of the integrals provides accurate estimates of intraparticle diffusivity and Peclet group for axial dispersion when additional information provided by the experiments is used to resolve interaction between the process coefficients in the dynamic response.

ISSN:0001-1541    

DOI:10.1002/aic.690230108

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractGas holdup and the ratio of the turbulent regime mechanical power consumed in aerated compared to that in nonaerated aqueous phases were measured in two laboratory sized tanks. Standard six‐blade turbine (D/T= 1/3), six‐blade paddle (D/T= 1/3), and four‐blade paddle (D/T= 2/3) impellers were used over a wide range of impeller rotational speed and gas sparging rate. For all systems, the power ratio results were found to fit a semitheoretical correlation (derived from dimensional analysis) involving the impeller Weber number, the aeration number, and the ratio of dispersion and liquid densities. Empirical correlations for gas holdup in water, aqueous solutions of nonelectrolytes, and an aqueous electrolyte solution are given. The overall results lead to the conclusion that power ratio and gas holdup correlations are highly specific to a particular impeller type and are also dependent on the tank size and the liquid phase physicochemical prope

ISSN:0001-1541    

DOI:10.1002/aic.690230109

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractThis work involves a quantitative comparison between diffusion (or electrical conduction) and fluid flow occurring in the principal directions of certain simple anisotropic porous media, namely, clusters of parallel circular (or elliptic) cylindrical fibers. The degrees to which the observed macroscopic properties, permeability, and effective diffusivity (electrical conductivity) depend upon the direction of flow are determined analytically. Systems of parallel fibers are shown to be considerably more anisotropic with respect to fluid flow than with respect to diffusion (or electrical conduction), this effect being very pronounced with flattish fibers. It would not appear that any general analogy exists between diffusion (electrical conduction) and fluid flow occurring within anisotropic porous media.

ISSN:0001-1541    

DOI:10.1002/aic.690230110

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY

摘要:

AbstractThe solubility of sulfur dioxide in seawater in the range 10° to 25°C and 10−5to 1 molal is predicted based on a simplified chemical model. Estimates are also given of the resultingpHand the attendant distribution of sulfur and carbon dioxide species. Sulfur dioxide is considerably more soluble in seawater or other naturally alkaline waters than in pure wa

ISSN:0001-1541    

DOI:10.1002/aic.690230111

出版商:American Institute of Chemical Engineers    

年代:1977

数据来源: WILEY