Hydroplaning speed can be affected by pavement texture depth,thickness of water film,tire pressure and tread depth.In this study,to understand the influence of pavement texture on the hydroplaning speed,a new lab-scal...Hydroplaning speed can be affected by pavement texture depth,thickness of water film,tire pressure and tread depth.In this study,to understand the influence of pavement texture on the hydroplaning speed,a new lab-scale apparatus has been designed and manufactured.The lack of proportion between linear movement of vehicle shaft and the wheel rotation was found to be a good index to determine hydroplaning threshold.A 5%drop in the ratio of wheel-to-axle rotation has been assumed as an index to determine hydroplaning threshold.Based on the measures,a simplified model was developed that is able to predict the hydroplaning speed depending on pavement's texture characteristics.The results indicated that a 77%increase in mean texture depth cause 9%increase in hydroplaning threshold speed.展开更多
In order to investigate the physiological effects of airport noise exposure on organisms,in this study,we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 65 d.For c...In order to investigate the physiological effects of airport noise exposure on organisms,in this study,we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 65 d.For comparison,we also used unexposed control rats.Noise was arranged according to aircraft flight schedules and was adjusted to its weighted equivalent continuous perceived noise levels(LWECPN) of 75 and 80 dB for the two experimental groups.We examined rat behaviors through an open field test and measured the concentrations of plasma norepinephrine(NE) by high performance liquid chromatography-fluorimetric detection(HPLC-FLD).We also examined the morphologies of neurons and synapses in the temporal lobe by transmission electron microscopy(TEM).Our results showed that rats exposed to airport noise of 80 dB had significantly lower line crossing number(P<0.05) and significantly longer center area duration(P<0.05) than control animals.After 29 d of airport noise exposure,the concentration of plasma NE of exposed rats was significantly higher than that of the control group(P<0.05).We also determined that the neuron and synapsis of the temporal lobe of rats showed signs of damage after aircraft noise of 80 dB exposure for 65 d.In conclusion,exposing rats to long-term aircraft noise affects their behaviors,plasma NE levels,and cell morphology of the temporal lobe.展开更多
文摘Hydroplaning speed can be affected by pavement texture depth,thickness of water film,tire pressure and tread depth.In this study,to understand the influence of pavement texture on the hydroplaning speed,a new lab-scale apparatus has been designed and manufactured.The lack of proportion between linear movement of vehicle shaft and the wheel rotation was found to be a good index to determine hydroplaning threshold.A 5%drop in the ratio of wheel-to-axle rotation has been assumed as an index to determine hydroplaning threshold.Based on the measures,a simplified model was developed that is able to predict the hydroplaning speed depending on pavement's texture characteristics.The results indicated that a 77%increase in mean texture depth cause 9%increase in hydroplaning threshold speed.
基金Project supported by the National Natural Science Foundation of China (No. 1060408)the National Public Benefit Research Foundation of China (No. 200809142)
文摘In order to investigate the physiological effects of airport noise exposure on organisms,in this study,we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 65 d.For comparison,we also used unexposed control rats.Noise was arranged according to aircraft flight schedules and was adjusted to its weighted equivalent continuous perceived noise levels(LWECPN) of 75 and 80 dB for the two experimental groups.We examined rat behaviors through an open field test and measured the concentrations of plasma norepinephrine(NE) by high performance liquid chromatography-fluorimetric detection(HPLC-FLD).We also examined the morphologies of neurons and synapses in the temporal lobe by transmission electron microscopy(TEM).Our results showed that rats exposed to airport noise of 80 dB had significantly lower line crossing number(P<0.05) and significantly longer center area duration(P<0.05) than control animals.After 29 d of airport noise exposure,the concentration of plasma NE of exposed rats was significantly higher than that of the control group(P<0.05).We also determined that the neuron and synapsis of the temporal lobe of rats showed signs of damage after aircraft noise of 80 dB exposure for 65 d.In conclusion,exposing rats to long-term aircraft noise affects their behaviors,plasma NE levels,and cell morphology of the temporal lobe.
