摘要:

Kerosene was dispersed in water at a tee junction. The Sauter mean droplet size was determined as a function of flow parameters. It is shown that significant differences exist between this system and others which have been reported. Some of these differences can be attributed to the hypothesis that the system has not achieved dynamic equilibrium.

ISSN:0098-6445    

DOI:10.1080/00986449208935977

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In this paper, the bilinear control strategy for paper-making process is developed based on the characteristic of paper-making process. The bilinear decoupling control, bilinear observer and bilinear disturbance compensator as the typical techniques are discussed. Their applications to the headbox control of a paper machine at a real paper mill, as an example, are presented. On-line operation and simulation results show that the performance of the bilinear control system is satisfactory.

ISSN:0098-6445    

DOI:10.1080/00986449208935978

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Previously reported potassium sulphate crystal growth rate data in two mixed solvent systems viz. aqueous 2-propanol and aqueous propanone solutions within batch and continuous MSMPR agitated vessels respectively are re-analysed in terms of the surface integration effectiveness factor. In both cases, the effectiveness factor generally decreases with increasing concentration of the organic precipitants indicating increased diffusion control. At 2-propanol concentrations x =0.10 w/w and supersaturations σ>0.05, however, a local minimum in the effectiveness factor is detected indicating a change in mechanism consistent with an earlier kinetic analysis. These results demonstrate that the concept of effectiveness factors can be conveniently used to quantify the effect of solvents on the growth of potassium sulphate crystals.

ISSN:0098-6445    

DOI:10.1080/00986449208935979

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The viscous flow behaviour of emulsions of oil in non-Newtonian Ellis model fluids (aqueous solutions of sodium carboxymethyl cellulose) has been studied experimentally. The addition of oil droplets to a non-Newtonian aqueous suspending media leads to an increase in the apparent viscosity of the emulsion system. The shape of the emulsion flow curves (apparent viscosity versus shear-stress plots) is found to be similar to that of the suspending media; consequently, the emulsion flow curves at various oil concentrations (0 to 70% by volume) are described adequately by the Ellis model. The relative viscosities of the emulsions of oil in non-Newtonian aqueous suspending media are significantly lower than those exhibited by emulsions of oil in Newtonian media.

ISSN:0098-6445    

DOI:10.1080/00986449208935980

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The kinetics of the extraction of phenol from the aqueous phase by sulfuric acid salts of trioctylamine (TOA salts) in kerosene and the stripping of phenol from the organic phase by sodium hydroxide solution were studied using a constant interfacial area cell. Measurements of the extraction and stripping rates were made by measuring the time-dependent phenol concentrations in the aqueous phase. It is found that the extraction rate of phenol is strongly dependent on the initial concentration of phenol in the aqueous phase and on the initial concentration of TOA salts in the organic solvent. However, the effect of the total sulfate concentration and the acidic concentration on the extraction rate are not significant. The stripping rate is only a function of the initial concentration of phenol in the TOA salt-organic phase. By analyzing the experimental data, it was recognized that the extraction of phenol occurs at the interface, rather than in the bulk of the solution. The diffusion resistance, rather than the resistance of chemical reaction, is the rate-controlling step for the phenol extraction. Based on the experimental data, simple expressions of the extraction rate and stripping rate of phenol were obtained.

ISSN:0098-6445    

DOI:10.1080/00986449208935981

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A phenomenological model for phase separation in branching conduits (Hwangel al., 1988) has been extended and improved. These modifications involve new models for the phase distribution at the inlet of a branching junction corresponding to four different flow regimes, and a correction for flooding in vertical junctions. This mechanistically-based model gives good agreement when compared with representative experimental data.

ISSN:0098-6445    

DOI:10.1080/00986449208935982

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The deuterium content of hydrocarbons can be successfully determined using peak shape analysis of high resolution capillary chromatograms.

ISSN:0098-6445    

DOI:10.1080/00986449208935983

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In field-flow fractionation (FFF), a family of high resolution techniques for the separation of particles and polymers, the measured retention time of entrained particles eluting through a thin (50-500 μm) parallel plate channel is determined by the transverse forces acting on the particles during their migration. For particles in the size range ∼l-100μm an applied transverse driving force (in the present case sedimentation) rapidly brings the particles into balance with hydrodynamic lift forces, so that the two force vectors are equal in magnitude but opposite in direction. By subjecting latex microspheres of known size and density to a specified rotation rate in a centrifuge, the applied sedimentation force is known and thus the magnitude of the lift forces is immediately obtained. The transverse particle position can be determined from the measured particle retention time. Thus lift forces can be determined as a function of particle size, transverse position, and flowrate. This strategy has been used to characterize the lift forces acting on spherical particles driven close to one channel wall. This characterization promises to be useful for the improved understanding and optimization of FFF, crossflow membrane separation, and other processes involving particle motion close to walls

ISSN:0098-6445    

DOI:10.1080/00986449208935984

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Relationships are presented for predicting the decomposition heats and dissociation pressures of hydroxide, carbonate, sulfite and sulfate of magnesium and calcium at different temperatures. The proposed equations have been developed on the basis of thermodynamic data and experimental findings available in the literature. The results are also expressed in graphical form and are discussed from the standpoint of removal of sulfur dioxide from flue gas at different temperatures

ISSN:0098-6445    

DOI:10.1080/00986449208935985

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A linear stability analysis of a thinning film of non-Newtonian power law liquid has been employed to predict the critical thickness of rupture of films with immobile interfaces experiencing only van der Waals interactions. The assumption of immobile interfaces makes the above analysis equally applicable to the stability of foam as well as emulsion thin films. Psuedoplastic liquid thin films are found to be significantly less stable than Newtonian films. Power law liquid thin films are more stable for liquids with larger values of power law exponents and larger values of consistency indices. The critical thickness of film rupture is very sensitive to the power law exponent. As expected, the critical thickness of film rupture increases for stronger van der Walls interactions as well as for smaller surface tensions, these effects being more pronounced for psuedoplastic liquid films than their Newtonian counterparts.

ISSN:0098-6445    

DOI:10.1080/00986449208935986

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor