Length flow rate and

The kinetics of DEHP extraction from triple-layered tubing was studied by these authors by varying tube length, flow rate, and drug concentration. Figure 13 shows... 

Obviously, there are many ways to influence the capacity factors. However, the effects described above are predictable (see section 4.2.3) and in a sense trivial. It is worth noticing at this point that certain parameters do not at all affect the capacity factor and therefore do not at all affect chromatographic selectivity. These parameters include column length, flow rate and the diameter of packed columns. This renders these parameters irrelevant to the selectivity optimization process. In some cases they may be considered as parameters... 

Model unit operation to optimize operating -ariables (c.g. loading, bed length, flow rate and required plate count) ba.sed on thermodynamics (adsorption isotherm, separation factor, the column saturation capacity). 

The column must be equilibrated, re-equilibrated to the initial high aqueous solvent composition before another analysis can be performed. Normally this re-equilibration is included at the end of the gradient. How much equilibration time is enough In reality, it depends on the column length, flow rate, and the hydrophobicity of the sample peptides. Some chromatographers use 10 min as the standard equilibration time. Equilibration is all about fitness of purpose. One should determine the equilibration time experimentally the criteria should be, does the analyte really stick to the column and chromatograph appropriately and reproducibly for subsequent analyses. If this part of the method development is taken care of, it will undoubtedly be rewarded with improved chromatography and better cycle time. 

Duarte and colleagues used a factorial design to optimize a flow injection analysis method for determining penicillin potentiometricallyd Three factors were studied—reactor length, carrier flow rate, and sample volume, with the high and low values summarized in the following table. 

Although it has been common practice to specify the pressure loss in ordinary valves in terms of either equivalent length of straight pipe of the same size or velocity head loss, it is becoming more common to specify flow rate and pressure drop characteristics in the same terms as has been the practice for valves designed specifically for control service, namely, in terms of the valve coefficient, C. The flow coefficient of a valve is defined as the volume of Hquid at a specified density that flows through the fully opened valve with a unit pressure drop, eg, = 1 when 3.79 L/min (1 gal /min) pass through the valve... 

These design fundamentals result in the requirement that space velocity, effective space—time, fraction of bubble gas exchanged with the emulsion gas, bubble residence time, bed expansion relative to settled bed height, and length-to-diameter ratio be held constant. Effective space—time, the product of bubble residence time and fraction of bubble gas exchanged, accounts for the reduction in gas residence time because of the rapid ascent of bubbles, and thereby for the lower conversions compared with a fixed bed with equal gas flow rates and catalyst weights. 

Flow rate and pressure drop allowable established, determine pipe size for a fixed length... 

Flow rate and length kno Ti, determine pressure drop and line size. 

Velocity is a function of the cross sectional flow area thus, it is constant for a given flow rate and is independent of pipe length. 

The temperature of oil leaving a co-current flow cooler is to be reduced from 370 to 350 K by lengthening the cooler. The oil and water flow rates and inlet temperatures, and the other dimensions of the cooler, will remain constant. The water enters at 285 K and the oil at 420 K. The water leaves the original cooler at 310 K. If the original length is 1 m. what must be the new length ... 

Often, the retention time is used but, as discussed above in Section 2.3, this absolute parameter changes with column length and flow rate and this precludes the use of reference data obtained in other laboratories. To make use of these reference data, the capacity factor (k ), which removes such variability, must be employed. 

The separation nuaber is the only column efficiency par2uaeter that can be deterained under teaperature progr2uued conditions [45,46]. The critical parameters that aust be standardized to obtain reproducible SM values for coluans of different length are the carrier gas flow rate and the temperature program. The SN is widely used as part of a standardized test method to evaluate the quality of open tubular columns for gas chromatography (section 2.4.3). 

Some kinds of chromatography require relatively little optimization. In gel permeation chromatography, for example, once the pore size of the support and number of columns is selected, it is only rarely necessary to examine in depth factors such as solvent composition, temperature, and flow rate. Optimization of affinity chromatography is similarly straightforward. In RPLC or IEC, however, retention is a complex and sensitive function of mobile phase composition column type, efficiency, and length flow rate gradient rate and temperature. 

Numerous studies of NO removal in DBD have been carried out [20-36], The effect of electrode shape, discharge gap length, discharge polarity, gas composition and flow rate, and operation temperature on NO conversion will be considered. 

Namihira, S., Tsukamoto, D., Wang, H. el al. (2001) Influence of gas flow rate and reactor length on NO removal using pulsed power, T. IEEE Trans. PI. Sci. 29, 592-8. 

In the formulation of Bickel et al. (B7) which appears to be the most general formulation on this problem to date, both the feed and delivery conditions (temperature, pressure, flow rate, and composition) are specified. As before, the decision variables include the pipe diameters. But in addition, the number, placement, suction, and delivery pressures of compressors may also be varied within the constraints of overall pipeline lengths and network... 

The slopes of the peaks in the dynamic adsorption experiment is influenced by dispersion. The 1% acidified brine and the surfactant (dissolved in that brine) are miscible. Use of a core sample that is much longer than its diameter is intended to minimize the relative length of the transition zone produced by dispersion because excessive dispersion would make it more difficult to measure peak parameters accurately. Also, the underlying assumption of a simple theory is that adsorption occurs instantly on contact with the rock. The fraction that is classified as "permanent" in the above calculation depends on the flow rate of the experiment. It is the fraction that is not desorbed in the time available. The rest of the adsorption occurs reversibly and equilibrium is effectively maintained with the surfactant in the solution which is in contact with the pore walls. The inlet flow rate is the same as the outlet rate, since the brine and the surfactant are incompressible. Therefore, it can be clearly seen that the dynamic adsorption depends on the concentration, the flow rate, and the rock. The two parameters... 

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