摘要:

AbstractA novel plasma‐developed resist lithographic process is described that uses compressed CO2to extract nonvolatile siloxane molecules from host organic polymers. The process is capable of at least 0.75 μm resolution with an X‐ray sensitive guest siloxane‐host polymer system. A processing window was investigated and defined to eliminate or minimize film damage during compressed fluid extraction. Polymer deformation was usually avoided by using supercritical CO2rather than liquid CO2, provided that film thicknesses were ≤1 μm. Increased solute concentrations in the host polymer also adversely affected the quality of extracted films. Anin situcapacitance process monitoring scheme was developed which indicated that film damage, when observed, was primarily caused by explosive decompression of the solvent from the hos

ISSN:0001-1541    

DOI:10.1002/aic.690331002

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractThis quantitative analysis shows the relative effects of interfacial tension, interfacial viscosities, and wetting during displacement in a capillary whose radius is a sinusoidal function of axial position. The effect of the interfacial viscosities is to increase the resistance to displacement regardless of the wetting condition. The result are consistent with a previous qualitative analysis and with a previous quantitative analysis for displacement in capillaries whose radii are independent of axial position.In screening surfactant systems for potential use in tertiary oil recovery, it is recommended that the interfacial tension be minimized first, since it determines whether oil displacement will occur, and that the interfacial viscosities be minimized second, since they influence the rate of oil displacement.

ISSN:0001-1541    

DOI:10.1002/aic.690331003

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractThe local compositions of supercritical fluid carbon dioxide and a cosolvent about a solute at infinite dilution have been estimated for the first time using spectroscopic measurements. The solute was phenol blue, the bulk concentrations of the cosolventsn‐octane, acetone, ethanol, and methanol ranged from 0 to 100 mol%, and the pressure ranged from 80 to 300 bar. In each case, the clusters of solvent about the solute are enriched in cosolvent. Solubility data have been measured for phenol blue in CO2with and without the cosolvent acetone, and regressed using an augmented van der Waals‐density‐dependent local composition model to determine the relevant binary interaction energies. The local compositions calculated from the model agree with those that were esimated spectroscopically. The model was used to predict solubilities of solids in supercritical fluid CO2with various cosol

ISSN:0001-1541    

DOI:10.1002/aic.690331004

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA new model, called STICT for surface thermodynamics using ideal chemical theory, is developed for the surface tension of liquid metal alloys. It uses the Guggenheim approach to relate surface phase properties to those in the bulk. For strongly solvated metal mixtures, ideal chemical theory is used to characterize bulk properties. The STICT model fits experimental data well for the seven systems for which sufficient data exist. Moreover, calculations of bulk and surface true compositions give some guidance to the tailoring of the surface properties of alloys for various applications.

ISSN:0001-1541    

DOI:10.1002/aic.690331005

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractMost two‐product distillation columns can be described as 5 × 5 plants, but the control system design is usually simplified by means of the following procedure:1Choose two manipulated inputs for composition control (corresponding to a specific control configuration).2Design the level and pressure control system (usually three SISO controllers).3Design a 2 × 2 controller for composition control.This paper provides guidelines for step 1, which is considered the most important. Ratios (e.g.,L/DorV/B) are frequently chosen as manipulated inputs in step 1. It is shown that the ratio configurations are effectively complex multivariable controllers that provide, among other features, improved flow disturbance reject

ISSN:0001-1541    

DOI:10.1002/aic.690331006

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA mathematical model is formulated for the general class of problems that involve the transport of stable particulate suspensions in porous media. The porous medium is represented by a network of pore bodies (sites) and pore throats (bonds). Population balances for the species responsible for particle retention and permeability reduction are written in terms of the various mechanisms of particle capture and reentrainment. Rates of capture and release are evaluated using appropriate physical models. We specifically concentrate on mass transfer limited processes. The effective‐medium theory is suitably formulated to determine the fluid flow distribution in the network and to calculate the permeability. The network representation of the porous medium together with the population balances and the rates of deposition and release provide a consistent model that finds application in filtration and fines migration processe

ISSN:0001-1541    

DOI:10.1002/aic.690331007

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractEquations for the deep bed filtration problem are obtained as a special case of a general model formulated earlier. The filtration coefficient λ is expressed as an explicit function of system parameters such as fluid flow rate, pore density, and pore size distribution. For a unimodal pore size distribution it is found that λ remains constant both in space and time. In general, however, λ is shown to decrease. Explicit solutions to the problem, including particle density profiles and permeability, are obtained for the two cases of large values of the coordination numberZ(capillary tube model), and for a bimodal pore size distribution with a finite coordination numb

ISSN:0001-1541    

DOI:10.1002/aic.690331008

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA model developed by Sharma and Yortsos (1987a) is applied to the processes of fines migration and fines injection in a porous medium. The first is a problem frequently encountered in oil reservoirs when release of fines is triggered by physicochemical interactions of the porous formation with the injected fluids. The second may be a problem in the filtration of relatively large particulates. Simple solutions are provided for both processes by considering size exclusion as the dominant particle retention mechanism. The solutions developed provide expressions for the particle concentration profiles, the open pore density and pore size distribution profiles, as well as the permeability reduction. These expressions are of importance in the evaluation of the extent and depth of formation damage and can be used as designing tools for remedial treatment, such as acidizing or fracturing.

ISSN:0001-1541    

DOI:10.1002/aic.690331009

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA class of simplified emulsion polymerization models is developed. These models include the distribution of particle sizes and radical numbers, and the coupling of the particle initiation rate to the particle size distribution. An analytical solution to the modeling equations is found from contraction mapping. In addition, necessary and sufficient conditions for local stability are derived. These result in a simple criterion for the onset of oscillations in terms of kinetic rate constants and reactor operating conditions. The results clearly show that radical desorption, chain transfer agents, and certain types of impurities should have a strong influence on reactor stability.

ISSN:0001-1541    

DOI:10.1002/aic.690331010

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractThe problem of diffusion in pore networks of a certain class is considered, and a procedure for estimating effective diffusivities is formulated. The effective‐medium theory is used to obtain an effective conductance for the network, which is then used to determine the effective diffusivity starting from first physical principles and utilizing the observation that a network of pores of uniform conductance satisfies the smooth field approximation. Comparison of the estimated intraparticle diffusivities with those obtained from the exact solution of the transport equation for large networks reveals high accuracy and reliability of the method. Results for a number of pore networks show that the smooth field assumption should not be employed arbitrarily since it always predicts higher effective diffusion coefficients than the exact ones, by more than one order of magnitude in some case

ISSN:0001-1541    

DOI:10.1002/aic.690331011

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY