Search Results

The purpose of this study was to quantifiably evaluate driver mental fatigue using the power spectral analysis of the heart rate variability (HRV). The quantitative detector of driver fatigue can present appropriate warnings and help to prevent traffic accidents. A simulation creating driver mental workload was set up using vigilance, considered to be an accurate assessment of driver mental workload, to evaluate a driver's performance. In the experiment eight healthy male subjects were required to perform a vigilance task for 90 minutes. The physiological variables for evaluating driver mental load were spectral values of heart rate variability (HRV). As a result HRV showed a high correlation with driver mental fatigue.

In designing an automobile seat, it is important to minimize the fatigue experienced by the driver resulting from long-term sitting. In this study eight healthy male subjects participated in two group experiments that were A-group and B-group. Acupoints combined with magnetism stimuli were put on to the subjects for reducing postural fatigue in B-group during the simulated driving. The surface electromyography (sEMG) of muscle activity at L4/L5 as well as subjective self-reporting on fatigue were recorded and tested. Analyzing and comparing the EMG median frequency and the subjective evaluations between two groups a conclusion that acupoints combined with magnetism stimuli could reduce the driver postural fatigue was drawn.

In designing an automobile seat, it is important to minimize the fatigue experienced by the driver resulting from long-term sitting. In this study eight healthy male subjects participated in two group experiments that were A-group and B-group. Acupuncture was put on to the subjects for reducing postural fatigue in B-group. The sEMG of muscle activity at L4/L5 as well as subjective self-report on fatigue were recorded and tested. By analyzing and comparing the EMG median frequency and the subjective evaluations between two groups a conclusion was drawn that acupuncture could reduce the postural muscle fatigue effectively.

Shanghai had about a half million gasoline powered motorbikes in 2000. The motorbikes have become a significant contributor to ambient air pollution in Shanghai. This study selected an electric bike (e-bike) as a potential replacement for gasoline powered motorbikes. Life cycle assessment (LCA) was carried out for the two systems in terms of energy utilization and environment implications. LCA results indicated that e-bike is not better than the motorbike in all environment categories. The e-bike consumes less energy than the motorbike during its life cycle, and emits less GWP into air, and less BOD, COD, DS and HC into water. On the other hand, it generates more solid wastes, acidification potential, and HM than the motorbike, due to electric power production. Therefore, the Shanghai government should advocate advanced batteries and clean coal fired power plant technologies while implementing an electrical vehicle plan.

Many piston parameters and the profile of piston skirt should be optimized in order to get the best lubrication. To attain optimized parameters, a lubrication analysis of piston skirt was carried out. After having investigated the real condition, a numerical lubrication model was established and computer programs were worked out to simulate the performance of skirt, and every parameter can be modified to optimize the whole skirt parameters. In addition, an equipment to measure the oil film thickness between piston and bore was developed to verify the numerical simulation model. Because various parameters, like radial clearance, piston surface profile, piston pin offset, and skirt length, made experiments too difficulty to implement, the program simulation become exercisable and economical method. Through the simulation a group of optimized piston parameters could be obtained easily.