Ontology-based inference decision support system for emergency response in tunnel vehicle accidents.

Emergency response plans for tunnel vehicle accidents are crucial to ensure human safety, protect critical infrastructure, and maintain the smooth operation of transportation networks. However, many decision-support systems for emergency responses still rely significantly on predefined response strategies, which may not be sufficiently flexible to manage unexpected or complex incidents. Moreover, existing systems may lack the ability to effectively respond effectively to the impact different emergency scenarios and responses. In this study, semantic web technologies were used to construct a digital decision-support system for emergency responses to tunnel vehicle accidents. A basic digital framework was developed by analysing the knowledge system of the tunnel emergency response, examining its critical elements and intrinsic relationships, and mapping it to the ontology. In addition, the strategies of previous pre-plans are summarised and transformed into semantic rules. Finally, different accident scenarios were modelled to validate the effectiveness of the developed emergency response system.

Combustion behaviour and dominant shrinkage mechanism of flexible polyurethane foam in the cone calorimeter test.

The shrinkage is an important thermal response of flexible polyurethane foam (FPUF) in fire, which couples its first combustion stage and influences the initial fire spread. In this paper the combustion and shrinkage behaviours are quantitatively investigated and the shrinkage mechanisms are discussed. The critical heat flux for the shrinkage is about 13 kW/m2, between the critical heat flux for piloted ignition and that for non-piloted ignition. Above the critical value the shrinkage rate increases linearly with increasing the heat flux. As the foam density decreases both the shrinkage rate and the first peak of Figra curve which reflects the initial fire spread rate increase. The perceptible shrinkage originates from the decomposition via which the struts convert to the melts. Both the shrinking of struts and the gasification play a minor role. The collapse of porous structure, namely the melts filling into the pores to form the tar layer, dominates the shrinkage. The tar is composed of polyols produced after the first decomposition stage. Beneath the tar layer the porous structure is unchanged. To reduce the fire hazards of FPUF by its heat insulation merit it needs to maintain the porous structure at the first decomposition stage.