Experimental error power curves

Figure 17-46 shows such a performance curve for the collection of coal fly ash by a pilot-plant venturi scrubber (Raben "Use of Scrubbers for Control of Emissions from Power Boilers, United States-U.S.S.R. Symposium on Control of Fine-Particulate Emissions from Industrial Sources, San Francisco, 1974). The scatter in the data reflects not merely experimental errors but actual variations in the particle-size characteristics of the dust. Because the characteristics of an industrial dust vary with time, the scrubber performance curve necessarily must represent an average material, and the scatter in the data is frequently greater than is shown in Fig. 17-46. For best definition, the curve should cover as wide a range of contacting power as possible. Obtaining the data thus requires pilot-plant equipment with the flexibility to operate over a wide range of conditions. Because scrubber performance is not greatly affected by the size of the unit, it is feasible to conduct the tests with a unit handling no more than 170 m3/h (100 ftVmin) of gas.

Scattered results are reported in [2979], and there are too few data points near the IEP. Also, in [2980,2981], too few data points are available near the IEP to make a reliable estimate. In [2982], at one pH value is reported. In [2983], potentials were measured only at pH 1,4, and 12. The IEP was obtained in [2984] from ESA measurements for two titanias (source or characterization of the powers or experimental details were not reported). The unusually high IEP reported in [2984] may be due to experimental errors the sohd concentration was too low, and the electrolyte background was not subtracted. Among the results from [1726], only the IEP for Nd(Ol I), was used. The other lEPs are based on arbitrary interpolations. The pH reported in the (pH) plot in [208] was not the pH of the dispersion. A home-made apparatus was used in [267], atypical shapes of electrokinetic curves... 

Our analysis will examine whether either of these classes of model describes experiment. While a power law and a stretched exponential both can represent a narrow range of measurements to within experimental error, on a log-log plot a power law is always a straight line, while a stretched exponential is always a smooth curve of nonzero curvature. Neither form can fit well data that are described well by the other form, except in the sense that in real measurements with experimental scatter a data set that is descrihed well by either function is tangentially approximated over a narrow region hy the other function. 

Extensive comparisons of predictions and experimental results for drag on spheres suggest that the influence of non-Newtonian characteristics progressively diminishes as the value of the Reynolds number increases, with inertial effects then becoming dominant, and the standard curve for Newtonian fluids may be used with little error. Experimentally determined values of the drag coefficient for power-law fluids (1 < Re n < 1000 0.4 < n < 1) are within 30 per cent of those given by the standard drag curve 37 38. ... 

In Fig. 11 we compare our decoherence calculation with the experiments by plotting the interference fringe visibility as a function of the laser power. We observe a good agreement between decoherence theory (solid line) and the experiment (circles). The experiment is reproducible within the indicated error bars for a given laser alignment, but small displacements of the laser focus will influence the shape and slope of the observed decoherence curve. The difference between the theoretical and the experimental curve is of the order of this variation. 

At sea level (Z = 0), the pressure equals 1.01325 kPa and it increases exponentially with Z to the power 1.07. Based on Figure 4.7, we could conclude that this relationship fits the data very well up to 80 km. Figure 4.8 shows a deviation of no more than 10 mbar up until 20 km and then the absolute deviation approaches a very small number. The deviation between the predicted and experimental pressure of the physical model reaches 2 mbar up until the stratopause and then reaches a maximum of 12 mbar before dropping again. The percent deviation in the troposphere is superior for the physical model but the curve fit characterizes the entire data set very well. The error is as high as 50% in the mesosphere but the absolute difference between data and curve fit is only 0.006 mbar at 77 km. 

In fig.7-9 four curves of compressibility for roll press are shown. One curve represents the measured values and other three curves are predictions according to the particular equations of compressibility where parameters K, ao, ai, a.2, m were determined from curves of compressibility measured in a die press. It can be seen that equation (8) derived from simple linear modulus of volume transformation predicts the experimental values best. Equation derived from power modulus predicts the measured values in roll press with substantial error, although the equation fits measured values in die press and roll press very accurately. This fact is due to dependencies between parameters 02 nd m or in other words the equation is overparameterized. Prediction based on equation derived from linear modulus is not shown but substantial deviation between measured and predicted values also occurs. 

Past difficulties in experimental measurements of integrated infrared intensities have been associated mostly with the low resolving power of spectrometers, poor accuracy on the ordinate and absence of computer facilities for band integration, deconvolution and curve fitting in overlap parts of the spectra. It is clear that presently we have far better experimental means for accurate determination of die integrated intensities of individual absorption bands. Still, however, careful considerations of a number of possible sources of errors are needed in order to obtain sufficiendy accurate intensity data. Some of these problems will be discussed later on. 

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