Shu Xueming

Self-Preserving Size Distribution of Fire Soot Fractal Coagulation in Flaming Combustion

In this work, by carefully calculating the different Knudsen numbers, the free molecular and continuum regimes of flaming combustion were first explicitly defined as the soot particle growth zone low in the flame and the upper zone near the ambient air in the plume respectively, and the fractal coagulation theory was applied to analyze the soot particle agglomeration in the two cluster–cluster aggregation-dominating regions. The accurate analytical simplicity solution obtained proved that self-preserving size distribution (SPSD) exists in the two regions. Additionally we got the relation between the normalized number concentration of the total particle aggregates and the dimensionless time as well as the actual lag-time from monodisperse distribution to SPSD. The results indicate that the fractal morphology of the soot particles affects the particle coagulation process to a large extent, especially has a great influence on soot particle SPSD, total aggregates number concentration in the growth region and the time needed from monodisperse distribution to SPSD above the flame region near the air conditions. The validation of our theoretical results was verified in comparison with previous work and our experimental results.

Research of spatial distribution rules of mass incidents based on GIS

The research of hot-spots is an important subject in public safety field as well as GIS system application, it reveals the spatial distribution law of crime and help develop targeted security preventive strategy, providing safeguards for the whole society. The mass incident is a special kind of public safety incident, but there are little research on its spatial distribution rules from the perspective of geography. This article analyzes the spatial distribution rules of mass incidents in China from the macro point of view and based on the spatial autocorrelation and Kernel density estimation, then finds hot-spots and calculates the degree of spatial agglomeration to express the spatial distribution law of crime. CCS Concepts • Information systems➝ Database management system➝ Database design and models ➝ Graph-based database models.

Fire Smoke Particle Size Measurement Based on the Multiwavelength and Multiangle Light Scattering Method

A multiwavelength and multiangle mathematical model (MWMA) is developed, and the corresponding influence factors of the model are analysed by the numerical calculation. Combined with measurement data of radiation flux and the curve in theoretical calculation, particle sizes of different materials can be obtained. It is found that smoke particle size gradually decreases from land plaster, cotton wick, beech wood, polyurethane, sandalwood, decahydronaphthalene, to N-heptane.