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The objective of this study was to evaluate and correlate light transmittance (T), initial degree of conversion (IDC), and degree of conversion after 24 hr (DC24) for 22 composite resins (CR) for enamel and dentin use. The transmittance (n = 10) was measured with a spectrometer at a wavelength of 468.14 nm. The degree of conversion (DC; n = 5) was measured with Fourier Transform Near‐Infrared Spectroscopy before polymerization, immediately after photoactivation, and 24 hr after photoactivation. Both sets of values are provided as percentages. ANOVA and Games‐Howell (α = 5%) tests showed that Filtek Supreme Ultra gave the highest T values of all enamel CRs, while Esthet‐X HD presented the lowest. Meanwhile, Venus diamond gave the highest values of all dentin CRs, while Esthet‐X HD gave the lowest. For IDC and DC24, ANOVA showed differences between individual CRs and the two CR types (p < .0001). Despite the limitations of this study, it can be concluded that there was no correlation between T and either IDC or DC24 (p > .05); however, IDC and DC24 were strongly correlated (p < .05) by Pearson's correlation. That being said, as a higher DC reflects better mechanical properties, certain conclusions can be drawn about overall performance. The best IDC values were observed for the Opallis enamel resin and the Opallis and Premise dentin resins. Meanwhile, the best DC24 values were observed for the Opallis, Charisma, and Premise enamel resins and the Opallis and Premise dentin resins. Degree of conversion and light transmittance showed differences between composite resin types (enamel and dentin) and brands. It is important to know at the moment of composite choice taking into account mechanical and optical properties.

Considering the need for knowing the amount of biodiesel in fuels, in order to attend several legislations around the world, this work aimed to develop a new, rapid, and nondestructive time-domain nuclear magnetic resonance (TD-NMR)based method for the biodiesel content determination in diesel−biodiesel blends. Main findings have revealed that both the transverse relaxation time (T 2) and signal areas from relaxation spectra are highly correlated to biodiesel content in the fuel samples. The highest correlation was reached by applying PLS multivariate regression over T 2 decay curve profiles. Therefore, both univariate and multivariate approaches were able to determine biodiesel content in diesel−biodiesel blends with high accuracy directly from fuel samples in a simple, fast, and inexpensive way.