Concentration, initial mean

Concentrate. An action to intensify in strength or purity by the removal of valueless or unneeded constituents, ie separation of ore or metal from its containing rock or earth. The concentration of ores always proceeds by steps or stages. Liberation of mineral values is often the initial step. Concentrate also means a product of concentration, ie, enriched ore after removal of waste in a beneficiation mill. 

Names of substances, or their concentrations Free radical, as CH Concentration of substance A Initial mean concentration in vessel... 

Concenti ation The main special lands are Cg, that of the effluent from a vessel with impulse input of tracer = m/V,., the initial mean concentration resulting from impulse input of magnitude m C, that of the effluent from a vessel with a step input of magnitude Cy. 

Initial mean concentration with impulse input. 

The chief quantities based on tracer tests are summarized in Table 23-4. Effluent concentrations resulting from impulse and step inputs are designated Cg and C , respectively. The initial mean concentration resulting from an impulse of magnitude m into a vessel of volume is C = mfVr- The mean residence time is the ratio of the vessel volume to the volumetric flow rate, t = V fV or t = jo tCg dt/jo Cg dt. The reduced time is t = t/t. 

With an impulse input of magnitude m or an initial mean concentration C = mlVr, the material balance is... 

The data plotted in the figure clearly support the predicted positive dependence of crystal size on agitation rate. Precipitation in the crystal film both enhances mass transfer and depletes bulk solute concentration. Thus, in the clear film model plotted by broken lines, bulk crystal sizes are initially slightly smaller than those predicted by the crystal film model but quickly become much larger due to increased yield. Taken together, these data imply that while the initial mean crystal growth rate and mixing rate dependence of size are... 

The kinetic mechanism of emulsion polymerization was developed by Smith and Ewart [10]. The quantitative treatment of this mechanism was made by using Har-kin s Micellar Theory [18,19]. By means of quantitative treatment, the researchers obtained an expression in which the particle number was expressed as a function of emulsifier concentration, initiation, and polymerization rates. This expression was derived for the systems including the monomers with low water solubility and partly solubilized within the micelles formed by emulsifiers having low critical micelle concentration (CMC) values [10]. 

The initial titration aliquots were added automatically on the basis of the rate of change of EMF, mode (i), and the resulting time between aliquot additions was usually shorter than the 10 second equilibration time allowed in the mode (ii) titrations described above. The time differences were especially significant when the transmittance change per 0.05 cm3 aliquot was small, for example when the hyamine was present in excess at high salt concentrations. This means that the mode (i) titrations are more influenced by kinetic effects and so the measured curves are less distinctive as may be seen by comparing the results at 1.46% salt in Figures 6 and 7. 

C a C° concentration of substance A initial mean concentration in vessel, p. 506,508... 

The half-life of a reactant and the mean reaction time of a reaction are two measures of the time to reach equilibrium. The half-life ty2 is the time for the reactant to decrease to half of its initial concentration, or more generally, the time for it to decrease to halfway between the initial and the final equilibrium concentration. The mean reaction time t is roughly the time it takes for the reactant concentration to change from the initial value to 1/e toward the final (equilibrium) value. The rigorous definition of the mean reaction time t is through the following equation (Equation 1-60) ... 

An initial series of measurements concerned the accurate determination of the dilution factor. As is represented in Fig.5.16, the absolute position of the tubes of the process solution and of the sodium hydroxide solution over the rollers of the pump is different. One tube is situated higher on the roller than the other, which can lead to a small difference in flow rate. By determining the hydrogen peroxide concentration by means of titration of a sample taken from the bath and a sample taken at the exit of the detection cell (diluted solution), the dilution factor can be determined. Table 5.1 presents the results of 23 measurements of the hydrogen peroxide concentration, performed at a liquid flow rate of 11/h. It is concluded that the dilution factor equals 1.9773+0.0014, which in fact is very close to 2. 

Figures 3 through 6 show conversion-time data for a number of vinyl acetate runs. The start-up procedure for these experiments consisted of filling the reaction vessel with degassed water prior to introducing any feed streams. Periodic samples were taken and the monomer conversion measured gravimetrically. As can be seen, some of the conversion transients did not reach a steady state. Tendency toward unsteady behavior and the magnitude of the oscillations seemed to increase with increasing initiator concentration and mean residence time. The influence of changing the emulsifier concentration is not clear.

Given the low concentration and means of dispersal, the Tokyo subway sarin attack can be referred to as a passive attack. The implication of such an assumption is therefore that mankind has not yet witnessed a full-scale sarin attack in any major city. While valuable information can certainly be gained from the Tokyo subway sarin attack, the experience obtained from the more aggressive Matsumoto sarin attack and the Iran-Iraq war should also be considered when developing initiatives directed at dealing with a potential full-scale attack in the future where the effects will be more serious. 

Figure 8 Mean molsidomine concentrations (% initial) as a function of time for dynamic experiments, performed in simulated sunlight with an unprotected infusion bag and unprotected infusion tubing ( ), with an infusion bag, covered with aluminium foil and an unprotected infusion tubing (A), with an infusion bag, covered with a ultraviolet (UV)-cover and an infusion tubing with UV-filter ( ) n= 1). Source From Ref. 64.

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