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Photocured dental resins are used extensively in restorative procedures in dentistry. Inadequate curing reduces the lifetime of the dental restoration, and consequently it is essential to precisely measure the polymerisation kinetics. In this study, two techniques, Quartz Crystal Microbalance (QCM) and Photoacoustic Spectroscopy (PAS), were used to monitor the real-time cure and to obtain the optical absorption spectra of resins, respectively. From the PAS measurements, the precise peaks of absorption were identified, and were used as the appropriate wavelength of the photocuring light in the QCM monitoring. The combined use of these techniques allows reliable determination of the duration of the phases of physical and chemical changes that occur during photocuring. Two commercial dental resins were tested, and the results confirmed the advantages of using PAS and QCM to study polymerisation kinetics.

<em>Air pollution is one of the main environmental problems of modern society. The road and transportation segment is a key source of polluting gases worldwide. In its research for transportation’s emission reduction alternatives, the Brazilian government instituted a wide-spread biodiesel, adding 7% (B7) of biodiesel to the diesel used in the country. Therefore, studies such as this must be carried out to guarantee the environmental sustainability of the new matrix of renewable energies, with the use of biofuels, as well as evaluate the gases emitted to for the environment by the combustion of the same ones. This work was detected CO, CO₂ and NO gas emissions released into the atmosphere from the combustion of blends diesel/beef tallow biodiesel in a bench-scale engine. Using electrochemical sensors, the of these gases concentration were successfully registered for two modes of operation of the engine diesel, low rotation, 3500 rpm, and high rotation, 7000 rpm. The CO levels in this experiment in low rotation varied between values minimum and maximum range of 866.7 to 1333.3 ppm, and in high rotation, ranging of 666 and 1000 ppm respectively. For the CO₂ concentration in low rotation varied between values minimum and maximum range of 2.1 to 2.4%, and high rotation, ranging of 2.2 to 2.5%, and for NO concentrations of the samples for the mode low rotation had a variation of 83 to 109.5 ppm, and for high rotation were 81.7 to 98.7 ppm respectively.</em>