Process efficiency, influences

Back-diffusion is the transport of co-ions, and an equivalent number of counterions, under the influence of the concentration gradients developed between enriched and depleted compartments during ED. Such back-diffusion counteracts the electrical transport of ions and hence causes a decrease in process efficiency. Back-diffusion depends on the concentration difference across the membrane and the selectivity of the membrane the greater the concentration difference and the lower the selectivity, the greater the back-diffusion. Designers of ED apparatus, therefore, try to minimize concentration differences across membranes and utilize highly selective membranes. Back-diffusion between sodium chloride solutions of zero and one normal is generally [Pg.173]

The above simulations as to the occurrence of hot spots once more illustrate the power and promises of LES over RANS-type simulations. The hot spots can never be found by means of a RANS-type of simulation. The same technique was used by Van Vliet et al. (2006) to study the influence of the injector geometry and inlet temperature on product quality and process efficiency in the LDPE reactor. On the contrary, the RANS-based simulations due to R. A. Bakker and Van den Akker (1994, 1996) were pretty much suited to arrive at yield predictions for a fed batch reactor as a whole. 

A summary of the response variables obtained in this preliminary study are shown in Table 14, and the order ranking for the influence of process variables on the critical responses associated with coating process efficiency and drug release are provided in Table 15. 

Table 15 Rank Order Summary of Process Variables Influencing Coating Process Efficiencies and Drug Release Characteristics (Tso)...

A summary of the response variables obtained in this preliminary study are shown in Table 14, and the order ranking for the influence of process variables on the critical responses associated with coating process efficiency and drug release are provided in Table 15. As can be seen from the summary provided in Table 14, there is clearly an influence of the processing conditions used on ultimate drug release characteristics. On further examination, it was concluded that the major causes of the magnitude of differences in drug release characteristics were primarily due to ... 

Bacterial inactivation is achieved by CO2 absorption in the liquid phase, even though the reason why it happens is still not clear. In this respect, batch- and semi-continuous operating modes are substantially different. In the batch system the residence time, i.e., the time of contact between gas- and liquid phase, must be sufficient to allow the diffusion of CO2 in the liquid, and is therefore a fundamental parameter to assure a desired efficiency. In the semi-continuous system the contact between the phases is localized in the surface of the moving micro-bubbles. In this second case, the efficiency of the process is influenced by temperature, pressure, gas flux, bubble diameter, and other parameters that modify the value of the mass-transfer coefficient. Therefore, it is not correct to use the residence time as a key parameter in the semi-continuous process. In fact, a remarkable microbial inactivation is reached even with an exposure time of 0 min (i.e., pressurizing and immediately depressurizing the system) these two steps are sufficient to allow CO2 to diffuse through the liquid phase. 

The research subject in the given problem is the process of cementation based on squeezing out mercury from salt-acidic solution by means of a less useful metal, such as aluminum. A study of kinetics of the given chemical reaction shows that this process may be effectively conducted in a continuous chemical reactor. Process efficiency is measured by mercury concentration in the solution after refinement. This is simultaneously the system response as it may be measured quite accurately and quantitatively. These three factors influence the cementation process significantly Xi-temperature of solution, °C X2-solution flow rate in reactor, ml/1 and X3-quantity of aluminum g. The factor space is defined by these intervals 50[Pg.341]

At the present time, few, if any, details of chemical reaction mechanisms in coal conversion are known with certainty. This situation is particularly distressing in the areas of coal liquefaction and pyrolysis where chemical kinetics may strongly influence process efficiency and product quality. To improve this situation, in recent years a number of research groups have been performing chemical studies of coal and "model" compound reactions. 

Compounds most efficiently separated by LSC are non-ionic and relatively soluble in organic solvents (4). Because the solvent (mobile phase) interacts with the surface of the stationary phase, the separation process is Influenced by... 

It follows from the above explanation that electrolysis of alkali chlorides in an electrolyzer without a diaphragm must be interrupted before curve h which represents the concentration of hypochlorite oxygen changes into a horizontal line only under this condition is the process economical, as a prolonged electrolysis would result in a waste of current without any further increase in th<) hypochlorite content. Moreover, care should be taken to prevent the hypochlorite ions formed from being electrochemically oxidized, as this would result in lower current efficiency and lower hypochlorite concentration in the liquor produced. This process is influenced by a number of factors, e. g. brine concentration, hydrogen ion concentration, anode material, current density, temperature, and last but not least a suitable design of the electrolyzer. 

A pressure swing adsorption process (PSA) has been described with high efficiency for separation and capture of C02 in N2 at content from 16 to 25% (22). High purity C02 (> 99%) was recovered with efficiency ranging from 53% to 70% depending on C02 concentration. The selectivity and sorption capacity of zeolite 13X (FAU type) was much better than those of activated carbon. However, the influence of H20 on process efficiency was not reported. It is clear that H20, always present in flue gases from combustion, should first be separated to prevent inhibition of the zeolite. 

Fig. 8.15 Summary of factors influencing the reaction kinetics and the process efficiency of photo-initiated AOPs.

The chemical-mechanical polishing or planarization (CMP) process is a complex interplay between the wafer and the consumables involved. The consumables include slurry, pad, conditioner, and so on. During polishing, the pad carries the slurry and delivers it to the wafer surface. It also transmits the normal and shear forces from the polisher to the wafer. Therefore, polishing pad plays a critical role in the CMP process and influences the outcomes such as material removal rate (MRR), within-wafer nonuniformity (WIWNU), wafer-to-wafer nonuniformity (WTWNU), step height reduction efficiency (SHRE), and defect counts. 

The olefination reaction of BTFP sulfones could be performed with aldehydes and ketones. Efficiency and stereoselectivity of the process was influenced by various factors, such as structural features, base, solvent, etc. General trends are summarized in Table 20. 

Using a new planarization monitor, the planarization efficiency and planarization distance were computed for a copper CMP process. The influence of polish pad, slurry and process conditions was demonstrated. Results indicate that harder, stiffer pads can extend planarization performance to wider structures given a suitable choice of slurry. Process conditions play a relatively minor role. The planarization of copper during the as-plated copper overburden removal was found to exhibit similar behavior to the planarization of oxide topography in oxide CMP, with a planarization distance of approximately 2mm for a typical stiff-pad copper CMP process. 

The process parameters influencing the water vapor flux and energy efficiency are the temperature difference between hot and cold solutions, flow velocities of feed and permeate, air gap pressure, air gap width, and membrane type. 

How is the efficiency influenced by the BGE Peak I broadening is the result of different processes in CZE I occurring during migration [in addition, extracolumn effects contribute to peak width (e.g., that stemming from the width and shape of the injection zone, or the -f. aperture of the detector cell)]. If the system behaves I linearly, the individual peak variances (the second mo-9 ments), o j, are additive according to a... 

The assembly of rat liver FAS involves three stages synthesis of the multifunctional polypeptide chains, formation of the dimer, and attachment of a 4 -phosphopantetheine group by an enzyme-catalyzed reaction. This assembly process is influenced by changes in developmental, hormonal, and nutritional states. The FAS complex provides considerable catalytic efficiency, since free intermediates do not accumulate and the individual activities are present in equal amounts. 

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