摘要:

Ultrafiltration-induced polarization chromatography (UPC), belonging to the class of field-flow fractionations, is examined in some depth mathematically, and predictions based on this examination are tested against preliminary experimental data. Both analysis and experiments are performed for slit flow between porous confining walls with a superimposed cross flow perpendicular to these walls. Integration of the diffusion equation for an idealized two-dimensional flow suggests that UPC is a very promising alternate to gel permeation chromatography, both for determining polymer diffusion coefficients and estimating the molecular-weight distribution of mixtures. These predictions are borne out to a substantial degree by experiments with monodisperse native proteins, but it is clear that important practical problems remain to be solved. The most important of these are adsorption of protein and deviation of flow distribution from that modeled.

ISSN:0037-2366    

DOI:10.1080/01496397608085333

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The performance of 5A zeolite and a carbon sieve produced from coal for the separation of O2and N2from air has been studied. In static adsorption at 25°C, the zeolite took up more N2than O2. Conversely, for short adsorption times, the carbon sieve took up more O2than N2. This behavior was reflected when air was passed through adsorbent beds. For the zeolite, enriched O2was recovered in the outlet; for carbon, enriched N2was recovered. Possibilities for improving the performance of the carbon sieve are discussed.

ISSN:0037-2366    

DOI:10.1080/01496397608085334

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The effect of curvature on the transport coefficients of thermal diffusion in concentric-tube columns has been investigated and the results were obtained graphically. It has been found that the results for the nearly plane case obtained by Yeh and Ward still can be used for the extreme cylindrical case, with the transport coefficients multiplied by the modifying factors presented.

ISSN:0037-2366    

DOI:10.1080/01496397608085335

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The quantitative separations of Cd2+from Cu2+, Zn2+, and Pb2+, and of Cu2+from Ni2+and Co2+have been studied in details using varying concentrations of NaCl solution in acetone. In order to find the optimum conditions for the separation of these metal ions, a systematic study was made of various important factors, such as sample concentrations, eluent concentrations, pH, and ionic strength. The chromatographic behavior of 47 metal ions was also investigated using 1.0MNaCl solution in 30% acetone.

ISSN:0037-2366    

DOI:10.1080/01496397608085336

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

For a single plate the separation factor 5 depends only on the dimension-less time τ =Dt/Z2and the difference between the diffusion coefficients ΔD.The output for a certainScan be increased linearly with the plate thickness while simultaneously the diffusion time increases with the square of the plate thickness. For a cascade of 2 plates of equal thickness, the time scale for equalSis expanded by a factor 4 against the single plate. Simultaneously the output is increased by a factor 4β, where β is the efficiency coefficient for the transfer between the 2 plates.

ISSN:0037-2366    

DOI:10.1080/01496397608085337

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The device shown in Fig. 1 was found quite effective in removing large quantities of water from odor components. Water has always been a problem in odor component analysis because it deactivates chemical absorbers and hastens the degradation of chromatographic columns. This was clearly brought home to us once again during the examination of corn odors. The odor components are not especially volatile and are in low concentration. In order to increase the quantity of material coming from the corn, the corn was gently warmed. This caused large amounts of water vapor to be evolved which ruined the texture and absorption capacity of the chemical absorber being used. In order to remove the water and let the organic components pass, a piece of Whatman IPS, phase separation paper was placed in the vapor line. Phase separation paper is filter paper treated with a silicone which makes it nonwettable by water yet lets organic compounds pass through. Experience had shown us it worked well for separating liquids in two phases, and we found that it also works for separating gases. There is a build-up of back pressure but it was far less than that required to burst the line. After a few hours some water gets through; apparently the silicones are partially dissolved by the organic compounds. However, even then the vast majority of the water is still removed. We feel this technique may be of some use to other investigators, particularly since we know that few are aware of phase separation paper and what it can do.

ISSN:0037-2366    

DOI:10.1080/01496397608085338

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Preliminary consideration suggests that process time in diafiltration can be optimized. A mathematical derivation of the optimum time gives a surprisingly simple general relationship between the bulk concentration and the membrane surface concentration. Experimental values confirm that an optimum value can indeed be obtained.

ISSN:0037-2366    

DOI:10.1080/01496397608085339

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

A very simple procedure for separation of carrier-free144Pr and continuous milking of144Pr from144Ce in a alumina column has been developed. Cerous cerium was oxidized and adsorbed as ceric iodate in the column, and the praseodymium was eluted out unadsorbed. Study of the β-decay half-life of144Pr proved that the separated product is of high radiochemical purity. The separation process is rapid and the yield is quantitative.

ISSN:0037-2366    

DOI:10.1080/01496397608085340

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor