Bubble time

Figure 11 shows how the cyclic voltammetric shape of the reversible Co(II)/Co(III) oxidation of [Co(MeHsaldpt)] changes with increasing concentration (or increasing bubbling time) of dioxygen.15... 

Figure II Anodic cyclic voltammograms recorded at a mercury electrode in a dmso solution of [Co(MeHsaldpt) ] with the bubbling time of 02 [po2 1 atm] (a) deaerated original solution (b) after 4 min (c) after 6 min (d) after 30 min. (e) After bubbling again N2. Scan rate 0.2 V s ...

By any appropriate conventional viscosimeter, or by AOCS Bubble Time Method Tq 1A-64, assuming density to be unity. Fluid lecithin having a viscosity less than 7,500 centipoises may be considered a premium grade. Using Precision cone 73525, Penetrometer 73510 sample conditioned 24 hours at 25°C. 

The time for bubble growth to a hemisphere t, is the difference between the total bubble time Tb and the dead time x, p and L are pressure and gas flow rate and p and are the respective values at a critical point. From considerations discussed above about adsorption processes at the surface of growing drops it is concluded that the situation with the growing bubble is comparable, at least until the state of the hemisphere. Then, the process runs without specific control and leads to an almost bare residual bubble after detachment due to the very fast bubble growth. 

Fig. 5.11 Definition of characteristic bubble times and principal course of the pressure p in the bubble with time t...

Most of the instruments, based on the principle of maximum bubble pressure, do not allow the effective surface age to be calculated because the conditions during the bubble formation are unknown. These methods yield only a dependence of surface tension on bubble frequency or bubble time x. The graph in Fig. 5.14 shows the remarkable differences of the three possible form of final data y(Xb), y(x), and y(Xg). 

Fig. 5.14 Dynamic surface tension y in dependence of bubble time Tj, (— ), bubble life time t (—), and effective surface age Tj, ( ) (schematically)...

The effective surface age has been determined on the basis of a diffusion controlled adsorption model. Similar to the maximum bubble pressure technique, where the bubble time is longer than teff, the drop formation time t is also significantly longer than the effective age teff and can be obtained as teff=3t/7 [185], This estimation assumes a radial flow inside and outside the growing drop and a homogeneous expansion of the drop surface. 

Figure 15. Dependencies L(t) (top) and Ps(t) (bottom) for water (bubble time tb = 20 ms) obtained for a...

The results of Fig. 16 illustrate for water and a C BMPO solution how the bubble time tb = td + ti and dead time td can be determined via the gas flow oscillation method with measurement systems of different gas volume. For a given liquid, the td vs tb dependence is almost independent of Vg. 

Figure 16. The dependence of the dead time td on the bubble time tb = td + ti for water (2) and C12DMPO solution (1) for the capillary radius 0.85 mm and system volumes Vg = 1.5 ( ), 3.7 ( ), 4.5 (A) and 20.5 ml (A) lines 1 (C12DMPO solution) and 2 (water) are calculated from Eq. (49).

The viseosity of solvents can be determined by one of three methods glass viscometer, Saybolt viseometer, and bubble time method. Glass viscomelry is applicable to Newtonian, transparent liquids which because of volatility cannot be measured in conventional capillary viscometers. The viscometer uses a purge gas whieh helps to transfer the measuring liquid from a lower reservoir to the sample bulb. The time of flow is measured for a fixed volume of liquid at a temperature eonlrolledwifliapreeisionof 0.01"C. A set of liquids is available as viscosity standards in order to seleet the standard having closest viscosity to the measured sample. 

ASTM D 1545-93. Standard test method for viscosity of transparent liquids by bubble time method. ASTM D 5201-97. Standard practice for calculating formulation physical constants of paints and coatings. ISO/FDIS 11890-1-99. Paints and varnishes - Determination of volatile organic compound content (VOC)... 

The optimum operating conditions for ion flotation vary widely from system to system. The flotation pH, bubbling time, and gas flow rate should be carefully optimized, because in most cases it is difficult to observe when the flotation is complete. The quantities of surfactants should be greater than the stoichiometric amounts, but large excesses may decrease the flotation efficiency. An increase in the quantity of... 

McReynoIds RD, Lane JM (1971) Adapting the bubble-time method fm measuring viscosity of slash pine oleoresin. USDA Forest Service Research Note 147, Southeastern Forest Experiment Station, Asheville... 

The simplest way to remove oxygen from the solvent is to bubble the solvent with an inert gas, e.g., high-purity N2 or Ar. Since oxygen has a high solubility in organic solvents with respect to aqueous media, long bubbling time is often required. In order to avoid the... 

HCl bubble time 10 minutes (non hot DIW seal) > 50 hours, with HL126... 

Table 5. The overall impedance and HCl Bubble Time of Test Coupons After Immersion in 3.5wt% NaCl solution for 365 days (coupons were prepared in three different batches of anodization processes) [78].

ASTM D 1545-13. Standard test method for viscosity of transparent liquids by bubble time method. 

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