摘要:

AbstractMolecular theories of polymer rheology are reviewed with emphasis on predictions of the more familiar properties: non‐Newtonian viscosity and normal stress in steady shear, complex viscosity in oscillatory shear, and elongational viscosity in extensional flow. Both dilute and concentrated solutions are discussed, with emphasis on the former. An important objective is clarification of polymer modeling strategies and how they are related to polymer structure. The intended readership consists of those engineers familiar in a general way with continuum polymer rheology, but with no special expertise in polymer physical or theoretical chemistr

ISSN:0001-1541    

DOI:10.1002/aic.690210102

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractDevelopments in the theory of flooded porous electrodes are reviewed with regard to simulation of primary and secondary batteries, adsorption of ions and double‐layer charging, and flow‐through electrochemical react

ISSN:0001-1541    

DOI:10.1002/aic.690210103

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractThis paper describes an extension of an earlier study on oscillations which can develop on distillation trays. The oscillations take the form of violent lateral movements of the gas/liquid biphase, and they are generally undesirable for good column performance. It has been found that lower density gases need higher velocities to initiate oscillation, and vice versa for higher densities. The predictive method for the onset of oscillations proposed previously appears to remain valid for the range of gas density covered, and for small hole size trays. The presence of oscillations has been shown to increase weeping significantly.

ISSN:0001-1541    

DOI:10.1002/aic.690210104

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractThe numerical method of orthogonal collocation is used within a thermodynamically consistent framework to calculate equilibrium vapor compositions fromP‐T‐xdata for binary systems. The method may be used for isothermal or isobaric data in both the normal liquid and in the critical region, and it applies to any choice of standard states.To use the method it is necessary to have experimental or estimated values of vapor phase fugacity coefficients for both components in the mixture and liquid molar volumes (isothermal case) or heats of mixing (isobaric case). If vapor composition data are available, each set ofP‐T‐x‐ydata may be checked for thermodynamic consistency by comparingy(experimental) withy(calculated). Illustrative calculations are given. The method is shown to provide an excellent procedure for obtaining Henry's constants fromP‐xdata for systems with one noncondensabl

ISSN:0001-1541    

DOI:10.1002/aic.690210105

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractIt is shown that a pulse‐response technique can be used with the Wicke‐Kallenbach type of diffusion cell to determine effective diffusivities in catalyst pellets. The diffusivity is a function of the retention time of the pulse of diffusing gas in the pellet. Experimental values obtained with an alumina pellet agreed well with expected results for this type of mater

ISSN:0001-1541    

DOI:10.1002/aic.690210106

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractThrough an empirical but rational appraoch to the development of equations to represent the composition dependence of the excess Gibbs function for binary liquid systems, it has been found possible to correlate VLE data precisely, even for highly nonideal systems. This makes possible the application of Barker's method to the reduction of VLE data on a routine basis. The validity of the method is demonstrated through application to several sets of data from the literature, and new experimental data are presented for six diverse binary systems in vapor‐liquid equilibrium at 50

ISSN:0001-1541    

DOI:10.1002/aic.690210107

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractTotal pressure measurements taken for the ternay systems acetone‐chloroform‐methanol and chloroform‐ethanol‐n‐heptane at 50°C are reduced by Barker's method and correlated by an equation similar to one proposed by W

ISSN:0001-1541    

DOI:10.1002/aic.690210108

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractIn most industrial applications the linear model used for optimization by linear programming involves significant uncertainties and inaccuracies in the model parameters. This paper presents a framework which allows uncertainties in the matrix elements of the linear program to be taken into account without requiring detailed knowledge of the statistical characterstics of these uncertainties. Three cases for the inequality constrained problem are considered: independent variations in the array elements, column dependent variations, and row dependent variations. In each case the problem can still be solved as a linear program. In the first two cases, the problem size is doubled, while for the row dependent case a finitely terminating cutting plane algorithm is constructed.

ISSN:0001-1541    

DOI:10.1002/aic.690210109

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractThis paper presents a framework which allows uncertainties in the matrix elements of an equality constrained linear program to be taken into account without requiring detailed knowledge of the statical characteristics of these uncertainties. The results are derived using the model of the linear program with flexibility previously introduced for the inequality constrained case. However, because a feasible region common to all perturbed constraint sets does not exist in the equality constrained case, a flexibility set which intersects all perturbed sets individually rather than jointly is defined. The flexibility set is constructed by identifying a finite subset of all perturbed constraint sets which need to be investigated. Three cases for the equality constrained problem are considered: independent variations in the array elements, column dependent variations, and row dependent variations. In each case the problem is solved using a possibly large but decomposable linear program. In the first two cases, this program needs to be solved only once; while in the row dependent case an iterative but finite solution procedure is required.

ISSN:0001-1541    

DOI:10.1002/aic.690210110

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY

摘要:

AbstractThe problem of synthesizing an optimal low risk reaction network from unreliable reactions is formulated. An expected cost criterion function for decision‐making is derived both for the case of a continuously operating network of reactions and for the case of reaction paths that involve batch reactions. It is shown that in general the decision space has a nonserial structure and the search for the optimal path will involve use of network search methods. An example is given where the optimal reaction path is synthesized for deoxyribonucleic acid. This example demonstrates the decision‐making strategy for a class of bath reaction syst

ISSN:0001-1541    

DOI:10.1002/aic.690210111

出版商:American Institute of Chemical Engineers    

年代:1975

数据来源: WILEY