Simulation-based optimization of inner layout of a theater considering the effect of pedestrians

We propose an extended cellular automaton model based on the floor field. The floor field can be changed accordingly in the presence of pedestrians. Furthermore, the effects of pedestrians with different speeds are distinguished, i.e., still pedestrians result in more increment of the floor field than moving ones. The improved floor field reflects impact of pedestrians as movable obstacles on evacuation process. The presented model was calibrated by comparing with previous studies. It is shown that this model provides a better description of crowd evacuation both qualitatively and quantitatively.Then we investigated crowd evacuation from a middle-size theater. Four possible designs of aisles in the theater are studied and one of them is the actual design in reality. Numerical simulation shows that the actual design of the theater is reasonable.Then we optimize the position of the side exit in order to reduce the evacuation time. It is shown that the utilization of the two exits at bottom is less than that of the side exits. When the position of the side exit is shifted upwards by about 1.6 m,it is found that the evacuation time reaches its minimum.

Superatom-assembled boranes,carboranes,and low-dimensional boron nanomaterials based on aromatic icosahedral B_(12)and C_(2)B_(10)

Using the experimentally known aromatic icosahedral superatoms I_(h)B_(12)H_(12)2−and D_(5d)1,12-C_(2)B_(10)H_(12)as building blocks and based on extensive density functional theory calculations,we predict herein a series of core–shell superpolyhedral boranes and carboranes in a bottom-up approach,including the high-symmetry Th B_(12)@B_(152)H_(72)2−(2),C2h C_(2)B_(10)@B_(152)H_(72)(3),D_(3d)B_(12)@B_(144)H_(66)(4),I_(h)B_(12)@C_(24)B_(12)0H_(72)2−(6),and D_(5d)C_(2)B_(10)@C_(24)B_(12)0H_(72)(7).More interestingly,the superatom-assembled linear D2h B_(36)H_(32)^(2−)(8),close-packed planar D_(3d)B_(84)H_(60)^(2−)(10),and nearly close-packed core−shell D_(3d)B_(12)@B144H_(6)6(4)can be extended periodically to form the one-dimensional(1D)α-rhombohedral borane nanowire B_(12)H_(10)(Pmmm)(9),two-dimensional(2D)α-rhombohedral monolayer borophane B_(12)H_(6)(P m1)(11),and the experimentally known three-dimensional(3D)α-rhombohedral boron(R m)(12)which can be viewed as an assembly of the monolayer B_(12)H_(6)(11)staggered in vertical direction,setting up a bottom-up strategy to form low-dimensional boron-based nanomaterials from their borane“seeds”via partial or complete dehydrogenations.Detailed bonding analyses indicate that the high stability of these nanostructures originates from the spherical aromaticity of their icosahedral B_(12)or C_(2)B_(10)structural units which possess the universal skeleton electronic configuration of 1S21P61D101F8 following the Wade’s n+1 rule.The infrared(IR)and Raman spectra of the most-concerned neutral B_(12)@B144H_(6)6(4)and C_(2)B_(10)@C_(24)B_(12)0H_(72)(7)are computationally simulated to facilitate their experimental characterizations.

Fundamental diagrams for pedestrian flows in a channel via an extended social force model

In this paper, an extended social force model was applied to investigate fundamental diagrams of pedestrian flows. In the presented model, both the static floor field and the view field were taken into account. Then each pedestrian can determine his/her desired walking directions according to both global and local information. The fundamental diagrams were obtained numerically under periodic boundary condition. It was found that the fundamental diagrams show good agreement with the measured data in the case of unidirectional flow, especially in the medium density range. However, the fundamental diagram for the case of bidirectional flow gave larger values than the measured data. Furthermore, the bidirectional flux is larger than the tmidirectional flux in a certain density range. It is indicated that the bidirectional flow may be more efficient than the unidirectional flow in some cases. The process of lane formation is quite quick in the model. Typical flow patterns in three scenarios were given to show some realistic applications.