## 3 Applications of CWFP in Steady State Regime
Figure 6A shows the CWFP signal for 48 oilseeds flowing at 13 cm/s [32]. In this figure, each peak is due to a single seed and the peak amplitude is proportional to oil content (Figure 6B). Therefore, the CWFP method has the potential to measure the oil content in more than 20,000 intact seeds per hour. For this measurement, it is necessary that oil from the sample, from the same or different species, have a similar \(\mathrm{T}_{1}/\mathrm{T}_{2}\) ratio [32]. Figure 5: **(A)** Magnitude of CWFP signal in arbitrary unit (au) as a function of oil concentration of the sunflower oil dissolved in carbon tetrachloride, \(r=0.997\). **(B)** Magnitude of CWFP signal as a function of hydrogen content in various solvents: (1) chloroform, (2) 1,1,1 trichloroethane, (3) 1,2 dichloroethane, (4) benzene, (5) cyclohexane, and (6) hexane; \(r=0.998\). Adapted from Publication [12], Copyright (2000), with permission from ACS Publications. Figure 6: **(A)** CWFP signal amplitude corresponding to 48 macadamia nut fragments with oil masses ranging from 0.1 to 0.7 g. **(B)** Oil mass as a function of CWFP peak amplitude for macadamia nut fragments with oil masses ranging from 0.1 to 0.7 g. A total of 96 peaks were obtained in a time of 14 s. The linear regression determination coefficient was \(R^{2}=0.95\). Adapted from Publication [32], Copyright (2007), with permission from ACS Publications. The CWFP signal was also used to monitor fast polymerization reactions. Figure 7 shows the CWFP signals during photo-polymerization reactions of methacrylate blends using three photo initiators: phenyl-propanedione (PPD-a), monoacylphosphine oxide (MAPO-b), and canphorquinone-c. The CWFP sequence was applied to the sample to reach the steady state regime with a constant \(\mid\)M\({}_{\text{ss}}\mid\) amplitude. Then, the sample was illuminated with a blue light, and CWFP decay was measured as a function of time. During the polymerization reaction, T\({}_{2}\) values decayed, reducing the magnitude of \(\mid\)M\({}_{\text{ss}}\mid\). Therefore, Figure 7 shows that CWFP can be used to monitor fast polymerization of these compounds largely used in cavity fillings in tenths of seconds. This figure shows that canphorquinone (photo initiators c), is the most effective initiator used and the methacrylate blend was completely polymerized in less than 20 s [34]. The same principle of CWFP decay due to a solidification process was used to measure the thermal diffusivity of natural rubber. The experiments were performed with small pieces of rubber. After the CWFP reached the steady state with constant \(\mid\)M\({}_{\text{ss}}\mid\), liquid nitrogen was added to the samples [35]. The time constant of the CWFP decay was used to calculate the rubber thermal diffusivity and the result was in the same order of magnitude as the thermal diffusivity measured using a standard method [35]. The CWFP sequence with T\({}_{\text{p}}\) = 300 \(\upmu\)s was used in high-resolution NMR to suppress non-deuterated solvent signals. The frequency offset was adjusted to suppress the solvent signal on resonance. The experiments used a CWFP train with a few hundred pulses, producing a null signal for the solvent line on resonance before the acquisition. The method has been used in one-dimensional (1D) and two-dimensional (2D) high-resolution NMR experiments [36].