Column influence

Table 6.2. Chapter 6 Water concentrations in columns influenced by wall hydropathic state ... 

Huysman, F. Verstraete, W. (1993a). Water-facilitated transport of bacteria in unsaturated soil columns influence of cell surface hydrophobicity and soil properties. 

The operation of the column influences a number of key stages, each equally important to the effectiveness of the absorption. These stages are described as follows, with a description of the way in which they are modelled. 

Unfortunately, the beam heats up the plasma considerably and increases the momentum of the plasma column, influencing the rotational speed of the plasma as well. Therefore, charge exchange spectroscopy can be used only in discharges with additional heating. In ohmic plasmas and plasmas heated by electromagnetic waves X-ray spectroscopy is the only diagnostic to determine the ion temperature, as well as the plasma rotation. 

The magnitude of the resistant force to hydrocarbon movement caused by capillarity is not influenced by the groundwater flow condition and is also given by Equation 4.15. The net driving force for a vertical height Zq of a hydrocarbon column influenced by vertically upward or downward directed groundwater flow can be derived from Equations 4.5 and 4.6 and equals... 

Harteveld WK, Mudde RF, van den Akker HEA (2003) Dynamics of a Bubble Column Influence of Gas Distribution of Coherent Structures. Can J Chem Eng 81 389-394. 

Diaz, M. E., Iranzo, A., Cuadra, D. et al. 2008 Numerical simulation of the gas-liquid flow in a laboratory scale bubble column. Influence of bubble size distribution and non-drag forces. Chemical Engineering Journal 139, 363-379. 

As already discussed earlier under Relationship of Theory to Practice of Liquid Chromatography , the sample volume and the solute amount thereby injected on to the column influence the efficiency of the column considerably. 

Figure 6.22 Membrane column, influence of reflux (recycled molar flow rate) on column length.

At first glance the problem of designing a control system even for this simple plant looks very complex. Indeed it is. The basically new feature for the control design of such a system is the interaction between the units (reactor, column). The output of the reactor affects the operation of the column in a profound way and the overhead product of the column influences the conversion in the CSTR. This tight interaction between the two units seriously complicates the design of the control system for the overall process. 

Kluytmans, Kuster, B.F.M., and Schouten, J.C. (2001), Gas holdup in a slurry bubble column Influence of electrolyte and carbon particles, Industrial Engineering Chemistry Research, 40 2 >) 5326-5333. 

Krishna R, Urseanu MI, Dreher AJ. (2000a). Gas hold-up in bubble columns influence of alcohol addition versus operation at elevated pressures. Chem. Eng. Process., 39 371-378. 

Design and execute experiments that explore how the nature of the stationary phase of a GLC column influences the separation of a mixture of volatile compounds having a range of polarities. Consult with your instructor regarding the variety of GLC columns that would be available for your investigation. 

In line with these considerations experience suggests that in carbonate sands the radius of the column influenced by vibroflotation is smaller than in less angular silica sands of comparable (relative) density. 

The ester and catalj st are usually employed in equimoleciilar amounts. With R =CjHs (phenyl propionate), the products are o- and p-propiophenol with R = CH3 (phenyl acetate), o- and p-hydroxyacetophenone are formed. The nature of the product is influenced by the structure of the ester, by the temperature, the solvent and the amount of aluminium chloride used generally, low reaction temperatures favour the formation of p-hydroxy ketones. It is usually possible to separate the two hydroxy ketones by fractional distillation under diminished pressure through an efficient fractionating column or by steam distillation the ortho compounds, being chelated, are more volatile in steam It may be mentioned that Clemmensen reduction (compare Section IV,6) of the hj droxy ketones affords an excellent route to the substituted phenols. 

Equations 12.21 and 12.22 contain terms corresponding to column efficiency, column selectivity, and capacity factor. These terms can be varied, more or less independently, to obtain the desired resolution and analysis time for a pair of solutes. The first term, which is a function of the number of theoretical plates or the height of a theoretical plate, accounts for the effect of column efficiency. The second term is a function of a and accounts for the influence of column selectivity. Finally, the third term in both equations is a function of b, and accounts for the effect of solute B s capacity factor. Manipulating these parameters to improve resolution is the subject of the remainder of this section. 

A chromatographic column provides a location for physically retaining the stationary phase. The column s construction also influences the amount of sample that can be handled, the efficiency of the separation, the number of analytes that can be easily separated, and the amount of time required for the separation. Both packed and capillary columns are used in gas chromatography. 

A second way to work with the data in Table 14.7 is to treat the results for each analyst separately. Because the repeatability for any analyst is influenced by indeterminate errors, the variance, s, of the data in each column provides an estimate of O rand- A better estimate is obtained by pooling the individual variances. The result, which is called the within-sample variance (s ), is calculated by summing the squares of the differences between the replicates for each sample and that sample s mean, and dividing by the degrees of freedom. 

Finally, we note that the size and shape of the particles of the packing, the packing technique, and column dimensions and configuration are additional factors which influence a GPC experiment. In addition, the flow rate, the sample size, the sample concentration, the solvent, and the temperature must all be optimized. Details concerning these considerations are found in analytical chemistry references, as well as in the technical literature of instrument manufacturers. 

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