Skewing factor

H= Ht Pi Fraction Misfiring ki = Variance Factor kiPi = Variance Factor times Fraction Misfiring Si = Skewness Factor HPi... 

In a real chromatogram the peaks often have profiles that are non-Gaussian. There are several reasons for this. Besides the accepted approximations, such as invariance of the distribution coefficient K with concentration, there are irregularities of concentration in the injection zone at the head of the column. Furthermore, the speed of the mobile phase is zero at the walls and maximum at the centre of the column. The asymmetry observed in the peak shape is measured by a parameter called the skewing factor, which is calculated at 10% of the peak height (Fig. 1.4) ... 

Figure 1.4—Distribution isotherms, a) Ideal situation corresponding to the invariance of the concentration isotherm b) Situation in which the stationary phase is saturated, hence the front of the peak rises faster than the end of the peak descends (in this case, the skewing factor is greater than one) c) Inverse situation the analyte is strongly retained by the stationary phase. The retention time is elongated and the rise time of the front of the peak is slower than the descent at the end of the peak, which appears normal. For each type of column, the manufacturers usually indicate the capacity of the column in ng/solute loaded before peak deformation is seen. Situations a, b and c are illustrated with real chromatograms in HPLC.

The observed asymmetry of a peak is measured by two parameters, the skewing factor a measured at 10 per cent of its height and the tailing factor TF measured at 5 per cent (for the definition of these terms, see Figure 1.4) ... 

Figure 3.8 The directional distribution of the skewness factor with (J — air injector at 500 psia) and without (2 — normal jet) microjet injection Mj = 1.38.

For correlated (skewed) factors, the communalities are derived from the multiple correlation coefficients according to... 

E erimental data on the bridging 2/1, 2/2 twills and 5.1 sateen cloth are compared with plain weave monofilaments in Figure 4.16. In the above table, tr and SF are the Standard deviation and skewness factor associated with the particle size distribution. 

It is desirable to obtain the result of statistical analysis of the digitized data for more detailed understanding of turbulence mechanism in a drag reducing pipe flow. Thus, in this work, we attempted to give a more quantitative analysis including the skewness factor and the flatness factor. 

It is well accepted that the ejection process in the organized motion of wall turbulence causes a negative value of the skewness factor. The experimental evidence shown in Figures 1 and 2 suggests that the fluctuating velocity caused by the... 

The second polynomial is a Redlich-Kister type of equation which includes a skewing factor k, similar to Eq. (1.28), and this was used to fit measurements at 375 K and higher temperatures where the hydrogen bonding... 

These skewness factors are widely used to specify the higher-order turbulence components, because the turbulence intensity in gas-liquid two-phase flows in the baths of metallurgical processes is much higher than those of single-phase pipe flows (Tu < 15%) and single-phase jets (Tu < 30%) [21,22], It is known that 5 = 0 and F = 3 for a Gaussian (normal distribution) error curve. 

High-order turbulence correlations such as skewness and flatness factors are commonly introduced to understand the detailed structure of turbulence. The skewness factor Su and the flatness factor for the vertical turbulence component, are... 

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