Dye concentration measurement

Figure 24.6 Temporal evolution of a concentration cloud along a river. The curves show cross-sectional averaged dye concentration measured at six sites in the Waikato River (New Zealand) below an instantaneous transverse line source. From Rutherford (1994).

Fig. 4. Microscope assembly for drop size and dye concentration measurements [after VerhofF(VII)].

It can be seen in Figure 6 that under conditions where the S/D ratio is as high as lOO/l, for CMC 9M, the value of T2 is proportional to dye concentration. Measurement at the lowest dye concentration, 1.25 x 10 %, for S/D = 100/1, could not be made because of loss of sensitivity under these conditions. 

Maximum pressure tested on the original machine Dye concentration measurement range Maximum number of packages... 

Key words dye concentration measurement, Beer-Lambert law, real-time monitoring and control, spectral additivity, spectral morphing. 

Maximum number of adsorption sites occupied by dye molecules The amount of adsorbate on the absorbent The concentration of dye i in admixture The concentration of dye on fibre at equilibrium The current eoncentration The desired concentration The dye concentration measured at time t The mass of the dye taken up per mass of the fibre, at time t and plane v... 

However, the evaluation of stain resistance by dye depletion is limited by its sensitivity to very small amounts of stain. Minute amounts of stain located on the top of the carpet pile may be visible but too small to be reproducibly and accurately measured by dye depletion. If a dye concentration measurement indicates that less than 3% of the dye initially present has been sorbed by the carpet, the depletion technique must be augmented with colorimetric measurements. 

In order to determine the liquid exchange mass flux at the interface due to the droplet deposition and the liquid reentrainment, Quandt (1962) measured the dye concentration in an isothermal annular flow. His steady-state model is similar to Vanderwater s as shown in Figure 5.22, except for his assumption that VId — Vh, = Vr Hence, the concentration balance of dye can be expressed as... 

A major drawback of synthetic thickeners when used with dyes is their sensitivity to electrolytes. Most soluble dyes behave as highly ionised electrolytes and disperse dyes contain anionic polyelectrolyte dispersing agents unless they have been formulated with nonionic systems specifically for use with acrylic thickeners. Consequently there is a loss of viscosity this can be quite pronounced although it depends on circumstances, particularly on the dye concentration. As already mentioned, this can be alleviated to some extent by copolymerisation with acrylamide during manufacture. Otherwise it is necessary to try to eliminate all electrolytes from the system or to increase the concentration of thickener. Such measures have their limitations in practice, however. Alternative synthetic thickening... 

A slug of dye is placed in the feed stream to a stirred reaction vessel operating at steady state. The dye concentration in the effluent stream was monitored as a function of time to generate the data in the table below. Time is measured relative to that at which the dye was injected. 

A different approach to design a self-calibrating dye was proposed [70], in which a viscosity-sensitive molecular rotor (2-cyano-3-(4-dimethylaminophenyl) prop-2-enoic acid) was covalently linked to a reference dye, 7-methoxycoumarin-3-carboxylic acid, which exhibited no viscosity sensitivity (40, Fig. 13). A ratiometric measurement, that is, rotor emission relative to reference emission, was shown to be widely independent of dye concentration [70]. However, the design of such a ratiometric dye poses some challenges because of resonance energy transfer from... 

In agreement with (6), regression of dye concentration data measured at the beginning of the test makes it possible to relate the dye conversion rate to the conditions set in the reactor at the beginning of the test. Changing the initial conditions of the tests enables the evaluation of kinetic parameters. 

Figure 14.17. Liposome fluoroimmunoassay depiction, in which antigen-liposome conjugates containing fluorescent dye (concentration quenched) compete with analyte antigen for antibody binding sites, followed by wash and detergent lysis, to release the fluorophore for fluorescence measurement.

M/], the total number of channels available Aq, the number of sites per channel ttbox and the total dye concentration [D Jtot can be measured. A numerical solution... 

The dye-clay composites were prepared by dispersing the clays in each solvent containing the dye at a quantity of 10-200% of the CEC. This experimental procedure led to almost complete intercalation at room temperature for 2-7 days. The composite was recovered by filtration and washing several times with each solvent for eliminating an excess of dye, and then dried in air. Assuming that the loss of dye adsorbed on the surface was fairly small upon washing, the net weight of dye intercalated was estimated from the residual dye concentration in a solvent measured by a colorimetric analysis. 

Laser flash photolysis has been performed with the halogenated derivatives in ethanol [374], Measurements of the triplet lifetimes as a function of dye concentration, laser power, and in the presence of electron donors allowed us to determine the rate constants collected in Table 17. 

Whereas the optical method indicates attainment of saturation coverage by the dye in its /-state, results obtained with the phase-separation technique show that, after reaching apparent saturation, further adsorption occurs as the dye concentration in solution is increased. The horizontal step observed with the phase separation measurement is in approximate agreement with the maximum surface concentration of dye in its /-state as determined by the optical method. Hence, it is concluded that, contrary to earlier suppositions (70), only the first layer of this dye is adsorbed in its /-state subsequent dye layers must be adsorbed in different states. 

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