Temperatures data capture

Figure 4.8 ECD data plotted as In ftp versus 1,000/7. These alkyl halides dissociate via activation of the molecule. They are designated DEC(l) for dissociative electron capture via activation of the molecule. The slope multiplied by R is equal to the activation energy in the high-temperature region. The low-temperature data were originally not explained, but could be an indication of a low molecular electron affinity. The curves were fit using both dissociation and molecular ion formation. Data from [16-19].

Reference has already been made to the range of applications of DTA and DSC. This section is concerned with a closer look at calorimetric measurements which link thermal power to heat capacity, dAq/dt = (Cg — and its integral, dAq/dt)dt, to energy or enthalpy. These linkages together with temperature form the basis of quantitative DSC. Computer systems for the control of equipment, data capture and subsequent analysis have combined to give increased versatility and results of far greater precision than was possible previously with chart recorders. 

Figure 3.8. Kinetic data from molecular beam experiments with NO + CO mixtures on a Pd/MgO(100) model catalyst [70]. The upper panel displays raw steady-state C02 production rates from the conversion of Pco = PN0 = 3.75 x 10-8 mbar mixtures as a function of the sample temperature on three catalysts with different average particle size (2.8, 6.9, and 15.6 nm), while the bottom panel displays the effective steady-state NO consumption turnover rates estimated by accounting for the capture of molecules in the support. After this correction, which depends on particle size, the medium-sized particles appear to be the most active for the NO conversion. (Reproduced with permission from Elsevier, Copyright 2000).

Rheological measurements. Routine viscosity measurements were made with a Wells-Brookfield micro-cone and plate viscometer, or a Brookfield LVT(D) viscometer with UL adapter. Viscosity-temperature profiles were obtained using the latter coupled via an insulated heating jacket to a Haake F3C circulator and PG100 temperature programmer or microcomputer and suitable interface. Signals from the viscometer and a suitably placed thermocouple were recorded on an X-Y recorder, or captured directly by an HP laboratory data system. 

Gas chromatographic data was obtained on a Tracor Model 220 gas chromatograph equipped with a Varian Model 8000 autosampler. The analysis column was a 1.7 m "U column, 4 mm id, filled with 3% SP-2250 packing (Supelco, Inc., Bellefonte, PA) held at 200 C. The injection temperature was 250 and the nitrogen carrier gas flow rate was 60 mL/min. The detector temperatures were 350 for electron capture and 190 for flame photometric. Detector signals were processed by a Varian Vista 401 which gave retention times and peak areas. 

In this particular example, the salt and temperature information was recorded, however with the inverse modeling approach, the values are not used in the computation of the PLS model. One might be tempted to want to account for these variables by including them as additional columns of R. However, this is not necessary, because the effects of these variables are already captured by the spectra. Complimenting the R matrix with variables related to or correlated with the c vector may be helpful if that correlation is different from what is already in R. This is in contrast to a more classical approach for analyzing these same data, discussed in Section 5.2.2.2. 

The MRC cycle calls for a 182°C cure temperature. The effect of cure temperature on residual stress was investigated by curing specimens at four other cure temperatures (171, 165, 160, and 149°C) while holding the dwell time (4 hours) constant. In Figure 8.18 the dimensionless curvature for these specimens is plotted versus the cure temperature. The curvature is reduced as the cure temperature is decreased with significant reduction in curvature obtained for dwell temperatures of 165°C or less. The final curvature as predicted by the viscoelastic process model is overlaid with the experimental data in Figure 8.18 and is shown to capture the trend. 

Some recent thermally stimulated current (TSC) data obtained by Martin and Bois (1978) are shown in Fig. 8. Here the maximum occurs at 264°K, giving Ei0 0.61 eV,forcrBj 10-1S cm2. Evidently, a was not varied in this experiment. Note that the dark current begins to increase rapidly near room temperature in these data. Here our analysis must break down since capture... 

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