Intercept point calculations

This temperature and its equivalent % S02 oxidized define the intercept point. The next several pages provide an intercept calculation worksheet and instructions. The worksheet is for the specific case of ... 

LOQ) will typically be higher than the instrumental detection limit (IDL), because of background analyte and matrix-based interferences. The BEC (blank equivalent concentration) used in Table 4.7 is the apparent concentration of an analyte normally derived from intercepted point of its calibration curve or by reference of the actual counts for that analyte in a blank solution. The BEC gives a good indication of the blank level, which will affect the IDL. Most often, the detection limits are calculated as three times the normal standard deviation of the BEC in a within batch replicate analytical measurement of a blank solution. Therefore, if the instrument is stable enough, this will give a better IDL than the BEC itself. The BEC is a combination of the contamination of the analyte in the solution, the residual amount of the analyte in the spectrometer and the contribution of any polyatomic species in the analyte mass. 

Pick out one of the exchangers represented on the curve. It is best to pick out a middle exchanger and one where the heat release curve is the easiest to read if the heat release curve is quite erratic. Choose four adjacent temperature points as represented by intercepted points on the curve. All will give approximately the same correction factor. For example, the terminal temperatures of the hottest shell will be Tj, T, t2 and ta. For purpose of illustration, we will use these to calculate the correction factor. 

Theil s method determines the slope of a regression line as the median of the slopes calculated from selected pairs of points the intercept of the line is the median of the intercept values calculated from the slope and the coordinates of the individual points. 

Your answer to Problem 14.1 already contains most of the required graph. You only need to calculate the intercept point. 

Calculate the second catalyst bed intercept point as described in Appendix M. Make sure that you use 685 K for the second catalyst bed gas input temperature. 

The scatter of the points around the calibration line or random errors are of importance since the best-fit line will be used to estimate the concentration of test samples by interpolation. The method used to calculate the random errors in the values for the slope and intercept is now considered. We must first calculate the standard deviation Sy/x, which is given by ... 

Equation 19 utilizes the Y-residuals, 1) — Y, where 1) are the points on the calculated best-fit line or the fitted 1) values. The appropriate number of degrees of freedom is A — 2 the minus 2 arises from the fact that linear calibration lines are derived from both a slope and an intercept which leads to a loss of two degrees of freedom. 

When the value of c exceeds unity, the value of n can be derived from the slope and intercept of the BET plot in the usual way but because of deviations at low relative pressures, it is sometimes more convenient to locate the BET monolayer point , the relative pressure (p/p°) at which n/n = 1. First, the value of c is found by matching the experimental isotherm against a set of ideal BET isotherms, calculated by insertion of a succession of values of c (1, 2, 3, etc., including nonintegral values if necessary) into the BET equation in the form ... 

Calculate reflux ratios. The minimum internal reflux ratio is a line from the intercept of the q line with the equiUbtium curve to the yP point on... 

The end points of the operating line on an XY plot (Fig. 15-13) are X., Y, andXy, Y., and the number of theoretical stages can be stepped off graphically. The equilibrium curve is taken from the Hand type of correlation shown earlier (Fig. 15-9). When the equilibrium line is straight, its intercept is zero, and the operating line is straight, the number of theoretical stages can be calculated with one of the Kremser equations [Eqs. (l5-14) and (15-15)]. When the intercept of the eqnihbrinm line is not zero, the value of YJK, should be used... 

It is advisable to start a constant-pressure filtration test, like a comparable plant operation, at a low pressure, and smoothly increase the pressure to the desired operating level. In such cases, time and filtrate-quantity data shoulci not be taken until the constant operating pressure is reahzed. The value of r calculated from the extrapolated intercept then reflec ts the resistance of both the filter medium and that part of the cake deposited during the pressure-buildup period. When only the total mass of diy cake is measured for the tot cycle time, as is usually true in vacuum leaf tests, at least three runs of different lengths should be made to permit a rehable plot of 0/V against W. If rectification of the resulting three points is dubious, additional runs should be made. 

If the width of the jet (calculated for free conditions) at the point of its intercept with the occupied zone exceeds the room width, side walls transform the jet as if it was formed by the linear jet impingement on a floor. 

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