摘要:

AbstractThis review paper surveys the state‐of‐the‐art of resource recovery from municipal, primarily residential, refuse. Unfortunately, progress in effecting the actual installation of full‐sized recovery facilities has been minimal. The work that has been done has been beset with technical, and more often, economic difficulties. However, the rising cost of traditional means of disposal may allow new systems to become economically competitive. Past research development efforts hold out promise of success and the nation may see the application of efficient technological solutions that in some localities will actually reduce the cost of refuse disposal below that of traditiona

ISSN:0001-1541    

DOI:10.1002/aic.690180603

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractThis is a review of the state‐of‐the‐art of rational and primarily quantitative approaches to the utilization of expert opinion in the inexact sciences, among which the engineering sciences must be included. Of primary concern is the decision‐maker's utilization of one or more experts, and the criteria and scoring rules used to evaluate their performance. Also reviewed are certain game‐theoretic strategies used by experts to maximize their own goal satisfaction. With this review, it is hoped that chemical engineers, when acting as decision‐makers, will be able to utilize expert opinion more effectively and will better understand the function of experts when it is necessary for them to adopt such roles

ISSN:0001-1541    

DOI:10.1002/aic.690180604

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractMicroemulsions, which are optically transparent oil‐water dispersions, were spontaneously produced upon mixing hexadecane, hexanol, potassium oleate, and water in specific proportions. The drop‐volume measurements of hexadecane‐water interface in the presence of hexanol or potassium oleate revealed that these surfactants decrease the interracial tension of the hexadecane/water interface. It is proposed that the interaction between these two emulsifiers at the oil‐water interface causes spontaneous negative interfaical tension resulting in interfacial instability and the formation of microemulsions.As the amount of water is increased, the microemulsion exhibits a clear to turbid to clear transition. Unlike the clear regions, the turbid region possesses birefringence. The development of birefringence is also accompanied by a sharp decrease in electrical resistance. High‐resolution (220 Mc) nuclear magnetic resonance data suggest that water exists in two distinct environments or structures in the birefringent region. The electrical, birefringence, and nuclear magnetic resonance data agree with the proposed mechanism of phase‐inversion of microemulsions, which can be described as water spheres to water cylinders to water lamellae to a continuous water phase. The spontaneous formation of such structures (for example, water cylinders and lamellae) presumably depends upon the phase‐volume ratio and the interfacial tension at the oil‐

ISSN:0001-1541    

DOI:10.1002/aic.690180605

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractThe expressionY= (1 +Zn)1/nwhereYandZare expressed in terms of the solutions for asymptotically large and small values of the independent variable is shown to be remarkably successful in correlating rates of transfer for processes which vary uniformly between these limiting cases. The arbitrary exponentncan be evaluated simply from plots ofYversusZandY/Zversus 1/Z. The expression is quite insensitive to the choice ofnand the closest integral value can be chosen for simplicity. The process of correlation can be repeated for additional variables in series. Illustrative applications are presented only for flow, conduction, forced convection, and free convection, but the expression and procedure are applicable to any phenomenon which varies uniformly between known, limiting solutions.

ISSN:0001-1541    

DOI:10.1002/aic.690180606

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractThe one‐dimensional model for convection with diffusion and with a source term for mass or energy generation or interchange is analyzed for the eigenvalues and the corresponding spatial eigenmodes as a function of the Peclet number. It is shown how the modal analysis of the source case, when the source coefficients for heat exchange and chemical reaction are spatially independent, is directly related to the no source solution. Numerical examples of determining the source term coefficient are included. These solutions form a base to discuss dynamic characteristics and stability and to which solutions for spatially dependent coefficients can be compare

ISSN:0001-1541    

DOI:10.1002/aic.690180607

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractA method for performing time‐optimal control with only limited prior knowledge of specific process dynamics is described. The time constants of the process are identified during the transient period accompanying the desired set point change, and the valve switching times of the control algorithm are calculated based on these time constants. The adaptive features of this method make its use independent of process or operating variation. The effectiveness of the proposed control method was evaluated using digital simulation and experimental techniques. The experimental phase which involved random changes to the temperature set point of a batch reactor was carried out with the aid of an on‐line digital compu

ISSN:0001-1541    

DOI:10.1002/aic.690180608

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractGeneralized depletion curves for desorption (and breakthrough curves for adsorption) were calculated for a system characterized by the Langmuirtype equilibria and controlled by a film type rate model. The depletion points generally appear sooner than the corresponding breakthrough points, and the desorption profiles are significantly broader than the corresponding adsorption curves. These phenomena may be best explained in terms of the prevailing driving forces. The effects of adsorbate properties and operating variables (inlet composition and flow rate) were established and experimentally substantiated.

ISSN:0001-1541    

DOI:10.1002/aic.690180609

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractGas chromatographic techniques were used to measure the diffusion coefficients and the isosteric heats of adsorption of CO2, NO, NO2, and SO2on 5A and 13X molecular sieves, natural mordenites, and synthetic Na‐ and H‐mordenites in the temperature range of 133 to 325°C. Diffusional resistances for all gases studied decrease in the following order: natural mordenites>Na‐mordenites>H‐mordenites>(13X, 5A) indicating the increased ease of flow in the 3‐dimensional network. Isosteric heats of adsorption (range from 3 kcal/mole to 12 kcal/mole) and activation energies (range from 3 kcal/mole to 19 kcal/mole) decrease in the same order. The variations of diffusion coefficients, heats of adsorption, and activation energies are discussed in terms of the interaction between the surface and gas molecules as well as the openings of the pores relative to the size of the diffusing

ISSN:0001-1541    

DOI:10.1002/aic.690180610

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractThis experimental study shows effects of anionic and cationic surface active agents on mass transfer during drop formation, fall, and coalescence for both continuous and disperse phase‐controlled systems. Three dispersion nozzles, mounted with 1.906 cm equilateral pitch, and a 5.08 cm I.D. extraction column were used to simulate certain conditions in commercial liquid‐liquid extraction units.The surfactant effects on extraction were pronounced, frequently reducing transfer to 10% of that in uncontaminated systems, with marked minima at intermediate concentrations of surfactant. In contrast, the continuous phase coefficient during coalescence was substantially increased by surfactants, with maxima in some ca

ISSN:0001-1541    

DOI:10.1002/aic.690180611

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY

摘要:

AbstractA finite element method is applied to isothermal incompressible two‐dimensional slow flows of power‐law fluids. Examples considered are rectangular and axisymmetric converging channel flows, recirculating flows in rectangular channels, and flow round cylinders. Results are successfully compared with both finite difference and analytical solutions. The flexibility of finite element methods makes them very suitable for problems involving complex boundary geometries. The method used is particularly suitable for non‐Newtonian flows and can treat both rectangular and axisymmetric geome

ISSN:0001-1541    

DOI:10.1002/aic.690180612

出版商:American Institute of Chemical Engineers    

年代:1972

数据来源: WILEY