A combined velocity and temperature measurement method using a high-speed camera, a pulsed UV laser, and temperature-sensitive phosphor particles is proposed. The temperature was calculated from the phosphorescence lifetime, while the velocity was obtained from images of the phosphor particles during a single decay. This method was applied to in-cylinder measurements of gas flow at high temperatures under motoring conditions. Tumble flow was observed at the top dead center. The temperature-change dependence on the crank angle agrees qualitatively with the gas temperature and the pressure.

The stress and loading rate on disks of ${\mathrm{SrAl}}_2{\mathrm{O}}_4\text{:}\mathrm{Eu}$ mixed epoxy resin were measured by a lifetime-based method. The concentration of the mechanoluminescence (ML) phosphor and the excitation power did not affect the measured lifetime. The lifetime was proportional to the stress and was inversely proportional to the loading rate. The concentration, the excitation power, the stress, and the loading rate affected the peak intensity of ML, while previous work estimated the stress using the absolute intensity under well-controlled excitation and concentration conditions. The method used here can shorten the measurement time and enhance the practicality of a ML phosphor.