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With the rapid development of the economy, the expressway has been used as a main mode of transportation due to its function to meet traffic demand of people and thus has been given full attention. But, at the same time, it has gradually become the main cause of pollution of traffic environment. To clarify the degree of pollution caused by expressway vehicle and improve the expressway pollution diagnosis system, upon the notion of low-carbon transportation, this paper divides expressway environmental pollution into four types: air pollution, photochemical smog pollution, noise pollution, and vibration pollution, and analyzes each of them, respectively. Then, a comprehensive diagnosis model of environmental pollution caused by running vehicles will be built. This paper monitors the pollution intensity on different spots on the expressway to obtain the single-vehicle factors of various pollutants of the motor vehicles. Combined with the geographic information system, this puts forward the diagnosis methods in terms of the environmental "air pollution," "photochemical smog pollution," "noise pollution" and "vibration pollution" caused by the expressway vehicles, respectively, and further establishes a diagnosis model of vehicle pollution corresponding to the characteristics of the expressway. The result of the case study on the actual monitoring data of six expressways in Jiangsu Province shows that the pollution diagnosis values of six expressways are all between (0.4, 0.6] which symbolizes "slight pollution." The research results can provide technical support for monitoring of environmental pollution caused by expressway more comprehensively and reasonably, and provide data support for formulating effective control strategies.

In this paper, the gas pollutants in motor vehicle exhaust are taken as the research object. The diagnostic index system of motor vehicle gas pollutants on environmental pollution is constructed, based on the environmental pollution caused by motor vehicle exhaust. The emission intensity of various types of vehicles was studied. The least-square method is used to construct the diagnostic functions of different types of vehicle gas pollutants; the vehicle emission factors of different types of motor vehicle gas pollutants are obtained. By exploring the spatial-temporal correlation of vehicle emissions under traffic conditions, uncertainty mathematical theory is used to establish a spatial-temporal diagnosis model of vehicle gas pollutants on environmental pollution, and multiple correlation coefficients are used to conduct accuracy test. The research results can not only determine the pollution problem of motor vehicle emissions to the environment but also effectively evaluate the emission level of gas pollutants in the exhaust gas of motor vehicles. The application results show that the spatial-temporal diagnostic model of vehicle gas pollutants for environmental pollution has better guiding significance and practical value in solving environmental pollution problems.

PurposeThis paper aims to study the oscillation phenomenon before chaos as well as its mechanism of occurrence in the energy-saving and emission-reduction system.Design/methodology/approachThe system dynamics analysis, phase portrait analyses, equilibrium point analysis and bifurcation curve were applied to this paper.FindingsFirst, the authors find an oscillation phenomenon previous to chaos. Second, on the one hand, the existence of two unstable saddles is the reason for the occurrence of oscillation phenomenon. On the other hand, the increasing of carbon emissions can arouse oscillation phenomenon.Originality/valueThis paper finds an oscillation phenomenon previous to chaos in the energy-saving and emission-reduction system. The mechanism of occurrence of oscillation phenomenon is studied. The existence of two unstable saddles is the reason for the occurrence of such oscillation phenomenon. The oscillation is related with fold bifurcation. The study also provides a theoretical basis for the further study of chaos control.

How to reduce pollution intensity and realize the coordinated development of the economy and environment has become a key issue for environment governance. This paper investigates the pollution intensity by applying the Resource-Economy-Pollution dynamical system (REP). The dynamic behavior of the system is analyzed by means of Lyapunov exponents and bifurcation diagrams. A new REP chaotic attractor is observed. In addition, the existence of two unstable saddles is the reason for the occurrence of oscillation phenomenon. The integrated pollution intensity is studied. We detect how integrated pollution intensity is influenced by the patterns of resource consumption, recycling intensity of waste and the speed of economic development over time. We find that increasing the intensity of waste recycling is effective in reducing pollution intensity, while the effect of slowing the resource consumption and economy is not obvious. From the point of view of energy conservation and economic development, a full analysis of factors that may relate to pollution intensity should be conducted before making energy policies.

In order to solve the safety operation problems of High-speed rail (HSR) in different areas and different sections under the rainstorm condition, an early warning process for the rainstorm disaster is designed. Furthermore, in order to control the operation risk, a HSR operation program with different rainstorm degrees is given out based on the analysis of rainstorm warning mechanism and rainstorm warning threshold in this paper. In addition, considering the reality that natural conditions vary greatly and the rainfall is very uneven, a data perception model of rainstorm (DPM) is proposed with correction coefficients for solving the calculation problem of precipitation for rainstorm warning. The DPM mainly adopts Paulhus’s empirical equation and uses the linear function to improve it for calculating the precipitation, which is able to calculate the hourly precipitation in different regional environments, and also effectively evaluate the rainstorm warning level of high-speed rail in this period. It can calculate and monitor the process by big data and MATLAB. The result of case analysis shows that the DPM has good practical value for solving the safety operation problem of HSR in different areas under rainstorm environment.