RESUMEN
A highly sensitive technique for analyzing surface tension and dynamic viscosity of nanofluids was reported. Multiwall carbon nanotubes suspended in ethanol were evaluated. The assistance of a Fabry-Perot interferometer integrated by a small sample volume fluid allowed us to explore the stability and mechanical properties exhibited by the nanostructures. The surface tension and dynamic viscosity of the colloid was examined by using interferometric optical signals reflected from a remnant drop pending at the end of an optical fiber. Nanosecond pulses provided by a Nd:YAG laser source with 9.5 MW/mm2 at 532 nm wavelength were used to induce mechano-optical effects in the liquid drop. The mechanical parameters were approximated, taking into account single optical pulses interacting with an inelastic mass-spring-damper system.
RESUMEN
BACKGROUND: The World Health Organization has reported that 1.35 million people die on the roads every year due to road traffic accidents. This paper focuses on exploring a passive safety system that reduces lesions in the overtaking run-over scenario. METHODS: Head Injury Criterion (HIC) and Combined Thoracic Index (CTI) were evaluated through numerical simulations using LS-Dyna®; in order to compare the computed results, three different speed scenarios were carried out (velocity of running over 40, 50, 60 km/h). RESULTS: The computed results were divided into groups, A for the run-over test without a passive security system and B for the run-over test with a passive security system. For case A.1, the HIC15 was 3325. For case A.2, the HIC15 was 1510, and for case A.3, the HIC 15 was 1208. For case B.1, the HIC15 2605, for case B.2, the HIC15 was 1282, and for case B.3, the HIC was 730. CONCLUSION: The comparative results show that the passive safety system installed on the bicycle has an increased benefit impact on the severity of the injury on vulnerable road users, decreasing the probability of cranioencephalic lesions in all study cases. In addition, the thorax injuries are cut down only in the impact scenario at a speed of 40 km/h.