Road lane markings play an essential role in maintaining traffic order and improving traffic safety and efficiency. Active luminous lane markings have emerged with advances in technology recently. However, it is still not completely clear what impact their application will have on drivers. This paper aimed to study the effectiveness of active luminous lane markings on highways at night. A driving simulation experiment was carried out based on advanced driving simulators at Tongji University. The driving simulation experiment involved 31 participants and 9 simulation scenes with 6 different types of lane markings models and the same 2-way highway segment, which was 5300-m long with four 3.75-m wide driving lanes. The study participants drove through the simulated highway while the vehicle operation data and the driver’s eyes changing data were continuously captured. Overall, the pupil area change rate, steering wheel speed, brake pedal force, gas pedal, lane departure, and operating speed indicators were selected to evaluate the effectiveness of the active luminous lane markings. The results are shown as follows: (1) the active luminous lane markings have excellent visual recognition performance at night. Compared with the passive luminous lane markings, the active luminous markings can reduce the mental and physical loads of drivers, increase the early braking distance significantly, improve the lane-keeping ability and smooth the operating speed; (2) for the specific parameter settings of the active luminous lane markings at night, the yellow lane markings are better than the white ones, the point-line-type lane markings are superior to the conventional-type ones, and the blinking frequency is reasonable to set, at a moderate level, as 40 times per min. The results suggest that there are positive effects of active luminous lane markings on the promotion of highway traffic safety and efficiency at night, providing theoretical support for the popularization and application of active luminous road lane markings.
In this study, naphthalene heat pipes were produced and filled with different materials to test the heat transfer performance. The relationship between the pipes' diameters, liquid content, wall temperature distribution, and transmission power was studied. An explosion test was designed to assess the operating temperature limit of the naphthalene heat pipes. The results demonstrated an optimum filling amount to optimize the pipes' heat transfer performance. In practical applications, it is very important to strictly control the wall temperature of naphthalene heat pipes. When the wall temperature of the evaporation section reaches approximately 600°C, they can easily explode.
This article employs the CoFlame Code to investigate the effects of hydrogen addition to fuel on soot formation characteristics in laminar coflow methane/air diffusion flames at atmospheric pressure. Numerical calculations were carried out using a detailed C1-C2 gas phase reaction mechanism and a soot model consisting of two pyrene molecules colliding into a dimer as soot nucleation, hydrogen abstraction acetylene addition (HACA) and pyrene condensation as surface growth, and soot oxidation by O2, O and OH radicals. Calculations were conducted for five levels of hydrogen addition on volume basis. To quantify the chemical effect of hydrogen, additional calculations are performed for addition of inert pseudo-hydrogen (FH2). The addition of H2 or FH2 does not have a strong influence on flame temperature. The results confirm that hydrogen addition can inhibit soot formation in the methane/air diffusion flame by reducing both the nucleation and surface growth steps of soot formation process. The effect of FH2 addition on soot formation suppression is more remarkable than H2, indicating that the chemical effect of hydrogen added to methane prompts soot formation. The dilution effect of hydrogen addition on soot formation suppression is stronger than its chemical effect on soot formation enhancement the present findings are consistent with those of previous numerical studies.
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