摘要:

For the hollow cylinder and the hollow sphere the separation factorScan be obtained, as for the plate, by generalization from the dimensionless time τ. Separation factors for the plate and the spherical shell are given by the same function of τ. The outfluxes, and accordingly the separation factorS, are equal for centrifugal and centripetal diffusion processes. With increasing outer radiusR2and constantR2/R1, the equally separated output increases with the square ofR2for the cylinder and with the cube ofR2for the sphere, while the time for equal separation increases with the square of the barrier thickness in both cases.

ISSN:0037-2366    

DOI:10.1080/00372367708058082

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A rigorous convective diffusion theory is formulated for the predictive modeling of field-flow fractionation (FFF) columns used for the separation of colloidal mixtures. The theory is developed for simulating the behavior of a colloid introduced into fluid in time-dependent flow in a parallel plate channel across which a transverse field is applied. The methodology of generalized dispersion theory is used to solve the model equations. The theoretical results show that the cross-sectional average concentration of the colloid satisfies a dispersion equation with time-dependent coefficients. The results of this work, in principle, are valid for all values of time since the introduction of the colloid. It is shown that these results asymptotically approach those of the nonequilibrium theory formulated by Giddings for large values of time.

ISSN:0037-2366    

DOI:10.1080/00372367708058083

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Concentration field-flow fractionation (CFFF) is proposed as a possible new subtechnique of field-flow fractionation (FFF). The equations for solute retention in CFFF are obtained as a function of solute distribution and the solute chemical potential increment, δμ°c, across the flow channel. The minimum practical value of δμ°cis related to the necessary increment, δCc, in the concentration of one component of a mixed solvent across the column. This leads to criteria for δCc, for the solvent component's flux, and for the channel width.

ISSN:0037-2366    

DOI:10.1080/00372367708058084

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The accuracy and precision of calculating retention times from means and peak maxima have been examined using an exponentially modified Gaussian as a model for tailed chromatographic peaks. At different levels of random noise, retention times could be determined with nearly the same precision using either the mean or maximum. However, the accuracies and precisions of the maxima were affected by the number of points used in the digital smooth and by the number of points recorded per unit of standard deviation. For two peaks of similar shape, consistency in the selection of points should usually permit differences in retention to be determined accurately and with approximately the same precision using maxima, means, or half-heights on the leading side of the peak.

ISSN:0037-2366    

DOI:10.1080/00372367708058085

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The chromatographic analysis of capsaicinoids and of oleoresin capsicum can indicate relative amounts of the pungent components and the sources of the samples. The present work describes gas chromatographic analyses of several natural and synthetic capsaicins as well as several oleoresins. Use of a high-temperature stationary phase allows good separation of the three major components of oleoresin capsicum. Differences between samples from various sources could be easily seen, both in the general pattern of the chromatograms and in the relative quantities of the major components. Analysis times were relatively short and no chemical derivatization was required.

ISSN:0037-2366    

DOI:10.1080/00372367708058086

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Permeation coefficients of urea and NH4+across liquid membranes of glycerine esters were determined. The enzymatic hydrolysis of urea was chosen to show the selectivity of the membranes with respect to urea and ammonium ions. The mass transfer rate for urea was up to 15 times higher than for ammonium ions.

ISSN:0037-2366    

DOI:10.1080/00372367708058087

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Solvent extraction procedures are presented for the removal of chromium, cadmium, and zinc from metal-finishing wastewater. The procedures utilize a 25% Alamine 336-xylene solution as the extractant. The three metals can be extracted selectively or simultaneously using a 100 to 1 aqueous phase to organic phase ratio. All three metals can be stripped from the organic phase with better than 99.5% efficiency with 4MNaOH. The regenerated reagent can be recycled and reused without any loss of extraction efficiency. The procedures are reproducible, rapid, and simple.

ISSN:0037-2366    

DOI:10.1080/00372367708058088

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Flotation is assumed to occur when a condensed film of surfactant forms on the particles to be floated, making their surfaces hydrophobic and permitting bubble attachment. This hemi-micelle formation is a cooperative phenomenon resulting from van der Waals forces between the hydrocarbon tails of the surfactant ions. The effects of temperature, ionic strength, and particle surface potential are examined by means of a statistical mechanical approach described by Fowler and Guggenheim. The effect of hemi-micelle formation at the air-water interface on the efficiency of flotation by a coulombic mechanism is also examined. Increasing temperature increases the surfactant concentration necessary for flotation; increasing ionic strength decreases this critical surfactant concentration, but also decreases the magnitude of the air-water surface potential, which decreases flotation efficiency.

ISSN:0037-2366    

DOI:10.1080/00372367708058089

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Cu(II) is effectively floated from synthetic mixtures and industrial waste samples by floc foam floatation using Fe(OH)3and sodium lauryl sulfate at pH's of approximately 6.5. The separation becomes marginal at ionic strengths above 0.25 [residual Cu(II) concentrations greater than 1 ppm]. A constant surface charge model for floc foam flotation is found to result in less effective binding than the constant surface potential model.

ISSN:0037-2366    

DOI:10.1080/00372367708058090

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0037-2366    

DOI:10.1080/00372367708058081

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor