A cellular automata evacuation model considering friction and repulsion

There exist interactions among pedestrians and between pedestrian and environment in evacuation. These interactions include attraction, repulsion and friction that play key roles in human evacuation behaviors, speed and efficiency. Most former evacuation models focus on the attraction force, while repulsion and friction are not well modeled. As a kind of multi-particle self-driven model, the social force model introduced in recent years can represent those three forces but with low simulation efficiency because it is a continuous model with complex rules. Discrete models such as the cellular automata model and the lattice gas model have simple rules and high simulation efficiency, but are not quite suitable for interactions’ simulation. In this paper, a new cellular automata model based on traditional models is introduced in which repulsion and friction are modeled quantitatively. It is indicated that the model can simulate some basic behaviors, e.g. arching and the “faster-is-slower” phenomenon, in evacuation as multi-particle self-driven models, but with high efficiency as the normal cellular automata model and the lattice gas model.

A real-time sensing system based on triboelectric nanogenerator for dynamic response of bridges

The strain of bridges under traffic loads is time-varying and of small amplitude(~10^(-6)),which is a type of cumulative response and needs long-term continuous monitoring.To precisely capture the time-varying responses,a dynamic strain triboelectric nanogenerator(TENG)sensor with superior response capability,sensitivity,self-powered,and long-term stability is proposed in this paper.An analytical correlation between the structural strain response signal and the detected electrical signal is established for long-term continuous quantitative strain measurements based on the principles of contact electrification and electrostatic induction.A series of experiments are conducted to investigate the output performance of the proposed lateral-sliding mode TENG sensors.The results reveal that,with the loading condition with frequencies lower than 10 Hz,the time-varying strain responses of the steel bridge within the range of 3 to 150 microstrains can also be detected with high precision of 0.1 microstrains.And it achieves long-term stability after 10000 loading cycles compared with commercial sensors.The proposed novel sensing theory and method based on TENG technology can be applied as a new alternative approach for monitoring realtime structural strain information quantitatively with general applicability and feasibility for bridges.

Multi-quasiparticle excitations and the impact of the high-j intruder orbital in the N=51^93 Mo nucleus

The level structures of 93 Mo are investigated using Large Scale Shell Model calculations,and reasonable agreement is obtained between the experimental and calculated values.The calculated results show that the lower-lying states are mainly dominated by proton excitations from the If5/2,2 p3/2,and 2 p1/2 orbitals into the higher orbitals across the Z=38 or Z=40 subshell closure.For the higher-spin states,multi-particle excitations,including the excitation of 2 d5/2 neutrons across the N=56 subshell closure into the high-j intruder 1 h11/2 orbital,are essential.Moreover,the previously unknown spin-parity assignments of the six higher excited states in 93 Mo are inferred from the shell model calculations.