With the ever-increasing development of those chemical parks (concentrated areas), the inherent hazards may remain the major leading cause of serious casualties, causing dramatic increases in deaths and injuries. Despite this, proper path beforehand can effectively minimise the number of deaths or injured. In this study, in order to better address the aforesaid issue, the pre-evacuation path planning was adopted to do so. This method can serve to prepare emergency response in case of extreme events, such as fires, explosions, or dangerous leakages, because these accidents could happen in chemical parks (concentrated areas). To that end, a framework was therefore proposed. First, the general risk representation was conducted. After the main hazards as well as the vulnerability within the facilities was identified, the interaction between those two factors could be expressed with matrices. This was followed by the analysis of the domino effect, which tends to occur under such circumstances. Second, individuals' visibility and inclination at each location to choose the nearest exit gate or shelter zone were analyzed by space syntax analysis. Third, a weighted risk map mainly composed of risk, individual's visibility, and inclination of exits was therefore generated. And the lowest cumulative risk path was simulated and analyzed accordingly. Finally, the map modified with received risks suggests that each individual's safest route from their current locations can be possibly simulated with Dijkstra's algorithm, which corresponds to the lowest cumulative risk. For the purposes of illustration and validation, a real case was adopted. The results demonstrated that this framework could provide both technical and theoretical support for the pre-evacuation path planning in chemicals-concentrated areas like chemicals-concentrated areas. 相似文献
Objective: Driving speed is a major concern for driving safety under reduced visibility conditions. Many factors affect speed selection in low visibility, but few studies have been conducted examining drivers' characteristics, particularly in China. The present study aimed to investigate the correlation between drivers' demographic information, driving ability, and speed choice in low-visibility conditions using a sample of Chinese drivers.
Methods: A self-designed driving ability scale was used to assess driving ability in reduced visibility conditions. The reliability and validity of 306 gathered questionnaires were examined in this article, and a structural equation model (SEM) was built to explore the predictors of drivers' speed selection behavior under reduced visibility conditions and to measure the relationships between various factors.
Results: Age and driving experience have no direct relationship to speed selection behavior in reduced visibility, but the frequency of using expressways and annual mileage are significantly related to the speed on roads that have a speed restriction of 80 or 120 km/h. Under reduced visibility conditions, driving ability has a significant effect on speed selection behavior, and driving skill (DS) is the most influential on speed selection behavior on roads with a speed limit of 120 km/h; otherwise, the effect of risk perception (RP) does not differ by speed choice on 3 roads with different speed limits. Driving speed in good weather also has a positive influence on speed selection behavior in low visibility.
Conclusion: Driving ability is directly associated with speed selection in reduced visibility conditions, and some demographic data indirectly influence speed selection. This study provides useful recommendations for drivers' training programs to reduce casualties from accidents in low-visibility conditions. 相似文献
The pollution of particulate matter less than 2.5μm (PM2.5) is a serious environmental problem in Beijing. The annual average concentration of PM2.5 in 2001 from seasonal monitor results was more than 6 times that of the U,S, national ambient air quality standards proposed by U.S. EPA. The major contributors to mass of PM2.5 were organics, crustal elements and sulfate. The chemical composition of PM2.5 varied largely with season, but was similar at different monitor stations in the same season. The fine particles (PM2.5) cause atmospheric visibility deterioration through light extinction, The mass concentrations of PM2.5 were anti-correlated to the visibility, the best fits between atmospheric visibility and the mass concentrations of PM2.5 were somehow different: power in spring, exponential in summer, logarithmic in autumn, power or exponential in winter. As in each season the meteorological parameters such as air temperature and relative humidity change from day to day, probably the reason of above correlations between PM2.5 and visibility obtained at different seasons come from the differences in chemical compositions of PM2.5. 相似文献
Results of analysis of 7Be, 137Cs and 210Pb on aerosol filters carried out from 1998 to 2010 in Monaco show that a weak correlation between activity concentrations of these radionuclides in the atmosphere and meteorological parameters has been found for 7Be and temperature (r = 0.50), 210Pb and temperature and humidity (r = 0.43 and 0.41, respectively), and 137Cs and precipitation (r = 0.51). The minimum and maximum 7Be activity concentrations were observed during 2000 and 2009, corresponding with the maximum and minimum solar activity, respectively. The maximum 137Cs activity concentration found in May-June 1998 was due to the accident at Algeciras in Spain. The deposition velocities of 7Be, 137Cs and 210Pb depended on the precipitation rate, and attained maximum values during dry seasons. The investigated radionuclides may be used as atmospheric tracers, especially in long-term periods. 相似文献