Procedia Engineering最新文献

The last mile in disaster relief distribution chain is the delivery of goods from a central warehouse to the evacuation centers assigned for a given area. Its effectiveness relies on the proper allocation of each kind of relief good amongst the demand areas on a given frequency. Because these operations involve a limited supply of relief goods, vehicles, and time, it is important to optimize these operations to satisfy as much demand as possible. The study aims to create a linear programming model which provides a set of recommendations on how the current disaster relief supply chain may be carried out, specifically on how distribution operations allocate supplies among demand nodes as well as the routes taken in a day. The areas visited per day would depend on the capacity of the vehicle fleet as well as on the routes that can be used. This linear programming model will use Balcik’s last mile distribution model, while modifying it for the relief operations in the Philippines. The model minimizes routing costs as well as penalty costs for unsatisfied demands. Map data is used for determining routes and historical data from previous disasters are used to determine the supply and demand for relief goods while providing a benchmark for results. The model produces recommendations for (1) Demand node schedule, (2) Best route for schedule, (3) Relief good allocation, and (4) Operational costs. It also provides the computational backbone for relief distribution decisions in the Philippines, allowing for more optimal operations in the future.

In this work, three types of structural modified epoxy adhesives were used to investigate the effect of stress concentrations on the fatigue behavior of notched bulk specimens. SN curves of un-notched and notched specimens were determined at constant amplitude and R = 0.1 in the range between N_f = 10³ (LCF) and N_f = 10⁶ (HCF). The following key conclusions were made: (i) fatigue strength was reduced due to the presence of notches, especially at the HCF; (ii) adhesives showed different values of notch sensitivity with values for the adhesives lower than typical values of metals; (iii) for un-notched samples fatigue strength was between 62 and 78% of tensile strength for N_f = 10³ and around 50% for N_f = 10⁶; (iv) for notched samples fatigue strength was between 67 and 78% of the tensile strength for N_f = 10³ and around 40% for N_f = 10⁶; (v) fractography evidenced the presence of voids and shear yielding around the notches, (vi) unnotched samples showed the same fracture behavior for both LCF and HCF with crack formation at the external surface. For notched samples there was a significant distinction between LCF and HCF with cracks forming at the notch root.

Emergency evacuation plan plays a key role for fire risk management and successful evacuation. In this work, a topological model of evacuation routes is established and the corresponding matrix function is also proposed in order to evaluate evacuation ability. Simultaneously, risk assessment of fire scenarios is made based on numerical simulation. And on this basis, the variation laws of risk indicators such as temperature, thermal radiation, the concentration of toxic gas are analyzed in details and dynamic risk assessment of evacuation routes is made. Introducing the concept of equivalent routes, the scheme of the best route for evacuee at each location is the one along with the shortest time and minimal risk and suggested based on the Dijkstra algorithm. And then, one case is presented and result indicates that this model can aid people to avoid crowdedness and evacuate as soon as possible under fire accident. The risk-based model is also useful for the evacuation planning.

In view of special low pressure environment in high-altitude plateau, the paper carries out simulation and field experiment of AFFF in high-altitude low pressure environment. The results show that: when ambient pressure changes from 101kPa to 24kPa, with the reduction of ambient pressure, the foam expansion of AFFF decreases, and drainage time of AFFF decreases first and increases later; the 59kPa is the extreme point of whole change process and the drainage time of AFFF fire extinguishing agent reaches a minimum under this ambient pressure. During the stage from 101kPa to 59kPa, the drainage time of AFFF decreases with the reduction of ambient pressure. It shows through field test that in the stage from 101 kPa to 59kPa, the performance parameters of AFFF foam are consistent with those in simulation experiment.

This paper analyses the underlying factors of a disaster ‘recovery process’. Based on a household survey, conducted ten months after the 2015 South Indian floods in two affected constituencies (Mylapore and Velachery) of Chennai, residents were asked how long they took to recover from the floods and whether they took actively part in the recovery process. The results highlight that residents from the more affected constituency (Velachery) took significantly longer to restore physical aspects (e.g. energy, water, roads, etc.), but only partially longer for social and economic aspects. Aspects of social capital (leadership, communication, ownership and trust) were rated equally low in both communities. However, individual actions to help others or participate in volunteer groups increased more significantly in the constituency that was more affected. The findings from this case study point-out that flood disaster events trigger residents to become more solidary and active to help others, but have little impact on triggering a more active interplay between communities and authorities. This highlights that flood disaster events do not change inherent structural and institutional relationships between key actors (local government, communities, private sector, academia and NGOs) involved in disaster recovery processes.