Semilog graph paper

Then semilog graph paper can be used to plot both phase angle and log modulus versus the log of frequency, as shown in Fig. 12.12. There are very practical reasons for using these kinds of graphs, as we will find out shortly. 

Plot these data on semilog graph paper. 

Thus, by graphing the data on semilog graph paper and drawing a straight line through the data it is possible to read Cp° from the intercept and calculate kel from the natural log slope, as in Eq. (18) ... 

The figure shows a plasma decay curve of a drug with first-order elimination plotted on semilog graph paper. The elimination half-life (t1/2) and the theoretical plasma concentration at zero time (C°) can be estimated from the graphic relationship between plasma concentrations and time. C° is estimated by extrapolation of the linear plasma decay curve to intercept with the vertical axis. 

The rate law can now be used in the design of an industrial CSTR. For those wl prefer to find k using semilog graph paper, this type of analysis is given in Chapter Summary Note.s on the CD-ROM. An Excel tutorial is also given in the Summa Notes for Chapter 3. 

Thus, plotting In C vs. time on linear graph paper or C vs. time on semilog graph paper should produce a straight line, as shown in Figure 12.5. The slope provides a value for (Equation 12.5) and the intercept provides a value for D/V. With D known, V can be calculated by Equation 12.6. 

From Equation 12.8 a plot of Qater - C vs. time on semilog graph paper provides an estimate of k, the absorption rate constant. The technique of curve stripping or method of residuals can be applied to equations involving multiple exponential terms when they differ by at least fivefold. 

Note that it is much easier to plot the competition data on semilog graph paper. The competition is plotted on an arithmetic scale and related to logjo of the competing Ig concentration. In this way, the values for the various concentrations can be directly read from the scale. This approach also simplifies all other data plotting in which the x-axis is a scale of activity. Figure 4 presents the same data plotted in this way. The values for the combination are shown in Table 6. 

It is evident from this relation that a knowledge of the decay constant Xooo as a function of the buckling aooo can yield considerable information about the various parameters which appear in (9.73). The principal task of the experimenter, then, is to obtain measurements of Xooo for various aooo- This can be accomplished, however, only if the higher modes have virtually disappeared so that the relation (9.70) is valid. Thus the first step in making the measurements is to record the neutron density, or some quantity proportional to it, as a function of time. When this function is plotted on semilog graph paper, the curve reduces to a... 

Graph paper with a logarithmic scale on the ordinate and a linear scale on the abscissa is called semilog graph paper. An example of 2-cycle semilog paper is... 

The half-life is readily obtained from a plot of time against enzyme content using semilog graph paper. 

The equation shows that in this type of relationship, logarithms of the y-values are related linearly to the x-values. Therefore, exponential relationships plotted on semilog graph paper, with the ordinates plotted on a logarithmic scale, are seen as straight lines (see Figure 7.11b). 

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