Dynamic capillary method

The following so-called dynamic capillary method was developed by Van Hunsel Joos (1987b) and complements the area of application with respect to other methods. This method allows measurements from 50 ms up about 1 s, similar to the inclined plate and growing drop techniques described above, and can be used at liquid/liquid and liquid/gas interfaces without modification. The principle of the experiment is schematically given in Fig. 5.23. Two fluids are contained in a tube of diameter R. The interface (or surface in case of studies at the water/air interface) is located in such a way that its interfacial tension can be measured by the capillary rise of the lower liquid in a narrow capillary c, which connects the both fluids. The height of the capillary rise h is determined via a cathetometer Cat. 

The dynamic capillary method described above also yields experimental data in a time interval from 50 ms up to several seconds (cf Fig. 5.27). A comparison with other methods is shown in Fig. 5.33 for an aqueous Triton X-100 solution. Again, the agreement is excellent and the deviations do not exceed the error in the individual methods. 

J. M. F. Douse, Dynamic Headspace Method for the Improved Clean-up of Gunshot Residues prior to the Detection of Nitroglycerine by Capillary Column Gas Chromatography with Thermal Energy Analysis Detection, Journal of Chromatography 464 (1989) 178. 

Dynamic surface tensions of an aqueous l.5510" mol/cm Triton X-100 solution measured with the dynamic capillary (0), inclined plate (A,A), drop volume ( ), strip ( ) and Wilhelmy plate ( ) methods according to Rillaerts Joos (I9S2)... 

A static capillary osmometer is illustrated in Fig. 1.7. Rather than rely on the liquid to rise in the capillary on the side of the solution in response to osmotic pressure, as is done in the static method, a dynamic equilibrium method can be used. Here a counterpressure is applied to maintain... 

The chemical diffusion coefficient is a phase property where the reference velocity is chosen in the Fick reference system. Various methods are known for the experimental determination of chemical diffusion coefficients, such as open and closed capillary methods, dynamic light scattering, or the Taylor dispersion method. 

The surface tension measurement techniques can be divided into the following three categories (i) Force Methods, which include the truly static methods of the capillary rise and Wilhelmy plate methods, as well as the dynamic detachment methods of the Du Nouy ring and drop weight, (ii) Shape Methods, which include the pendant or sessile drop or bubble, as well as the spinning drop methods, and (iii) Pressure Methods, which are represented by the maximum bubble pressure method. These techniques are summarized in the following sections of this chapter. 

Monolithic capillary microreactor Trypsin Adsorption Trypsin immobilized on matrix-HILIC by dynamic immobilization method high hydrolytic activity of BAPNA high enzymatic activity of standard proteins BSA, Cyt-C, and myoglobin sequence coverage of myoglobin and Cyt-C >50% [136]... 

Yan s group reported the first example of MOF-coated capillary column for high-resolution GC separation. MIL-101 was chosen as the stationary phase, and the MIL-101 crystals were coated on the capillary column by a dynamic coating method. A slurrylike suspension solution of MIL-101 is first filled into the capillary under gas pressure, and then pushed through the capillary at a steady speed, leaving a wet coating layer on the... 

ASTM F 151-97. Standard test method for residual solvents in flexible barrier materials. Withdrawn 2004. ISO 17052-07. Rubber, raw — Determination of residual monomers and other volatile low-moleoular-mass compounds by capillary gas chromatography — Thermal desorption (dynamic headspace) method. 

Porous structure of sorbents and catalysts determines basically the adsorption, diffusion and dynamical characteristics of many sorption and catalytic processes. Therefore the determination of pore structure parameters (such as pore volume and surface area) is attracted the attention of many scientists. Traditional methods for the study of porous structure (the Hg-porosimetry and capillary method) required usually the complex set up, which has many disadvantages and limitations (ref. 1, 2). 

In the past five years, it has been demonstrated that the QELS method is a versatile technique which can provide much information on interfacial molecular dynamics [3 9]. In this review, we intend to show interfacial behavior of molecules elucidated by the QELS method. In Section II, we present the principle and the experimental apparatus of the QELS along with the historical background. The dynamic collective behavior of molecules at liquid-liquid interfaces was first obtained by improving the time resolution of the QELS method. In Section III, we show the molecular collective behavior of surfactant molecules derived from the analysis of the time courses of capillary wave frequencies. Since the... 

Recently, the newly developed time-resolved quasielastic laser scattering (QELS) has been applied to follow the changes in the surface tension of the nonpolarized water nitrobenzene interface upon the injection of cetyltrimethylammonium bromide [34] and sodium dodecyl sulfate [35] around or beyond their critical micelle concentrations. As a matter of fact, the method is based on the determination of the frequency of the thermally excited capillary waves at liquid-liquid interfaces. Since the capillary wave frequency is a function of the surface tension, and the change in the surface tension reflects the ion surface concentration, the QELS method allows us to observe the dynamic changes of the ITIES, such as the formation of monolayers of various surfactants [34]. 

Dynamic surface tension has also been measured by quasielastic light scattering (QELS) from interfacial capillary waves [30]. It was shown that QELS gives the same result for the surface tension as the traditional Wilhelmy plate method down to the molecular area of 70 A. QELS has recently utilized in the study of adsorption dynamics of phospholipids on water-1,2-DCE, water-nitrobenzene and water-tetrachloromethane interfaces [31]. This technique is still in its infancy in liquid-liquid systems and its true power is to be shown in the near future. 

The solution of these dynamic nonlinear differential equations is considerably more complex than the previous systems considered. In particular, stable solution methods are based on physically realistic multiphase flow functions that have the following properties relative permeability functions are non-negative, monotoni-cally increasing with their respective saturation, and are zero at vanishing saturations, and capillary pressure is monotonically increasing with respect to the saturation of the non-wetting phase. It is necessary that any iterative scheme for estimating the multiphase flow functions retain these characteristics at each step. 

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