Modelling a social dilemma of mode choice based on commuters’ expectations and social learning

This study attempts to apply an agent-based approach to modelling a social dilemma of travel mode choice considering psychological and sociological aspects. A traveller is modelled to have expectations, which shows the traveller’s beliefs about the influence of other group members on his action, as decision-making rules. Social interaction using a group-based interaction is hypothesized to be important. We apply an imitation game based on social learning mechanisms to the model. Two kinds of mechanism are used: payoff-biased and conformist transmission. The model reveals the conditions that make cooperation as a possible outcome are optimistic bandwagon expectations, group-based interactions, and strong conformist transmissions.     

Numerical simulation of the haemodynamics in end‐to‐side anastomoses

In this paper, the commercial CFD package Ansys workbench 11 was used to analyse the three‐dimensional haemodynamics of a typical stenotic Coronary Artery Bypass Grafting (CABG). Two end‐to‐side CABG configurations with anastomosis angle of 20^° and 40^° and graft–artery diameter ratios of 1/0.6, 1/1 and 1/1.6 were examined. The flow measurements from in vitro Doppler guide wire technique acquired in left interior mammary artery (LIMA) and grafted to the left anterior descending artery (LAD) were used to impose the physiologically flow conditions at proximal and distal CABG inlet and outlet, respectively. The blood flow was considered to be incompressible, pulsatile, Newtonian, and laminar rheology. The main objective was to determine the effect of anastomosis angle and graft–artery diameter ratio on the flow patterns and the long‐term functionality of the graft. In analysing the results, the distributions of temporal and spatial wall shear stress (WSS) gradient and oscillating shear index (OSI) in the critical regions of CABG such as heel, toe and the centre of the junction were presented and the vortex motions and the occurrence of recirculation zones were examined. The findings showed asymmetrically disturbed flows in the localized regions of the proximal and distal host artery for all models considered and the movement of the recirculation zones from heel to toe was found to depend on the time at the cardiac cycle. These regions are known as susceptible sites to thrombosis and re‐stenosis due to their association with low values of WSS. Copyright © 2010 John Wiley & Sons, Ltd.     

Study on the time-dependent simulation and input parameter sensitivity of spent nuclear fuel electrorefining

A computer program for the simulation of spent nuclear fuel electrorefining has been developed based on general Butler–Volmer kinetics and mass transport within a diffusion layer model. The effect of a solid electrode area change due to the dissolution and deposition, the solubility of the element in the liquid Cd, and a volume change due to the development of metallic compounds were considered in this program. The program has been verified through Tomczuk et al.’s experiment, and the results show a good agreement of within 4 and 2 % for U amount in the anode and cathode, respectively. The sensitivity of several input parameters such as the standard electrode potential, activity coefficient, diffusion coefficient, diffusion layer thickness, and transfer coefficient has been tested. It was found that the standard electrode potential is very sensitive, as a 3 % variation leads to a U amount change of more than 30 and 50 % in the anode and molten salt, respectively. The sensitivity of the other input parameters is much less than the standard electrode potential, but significant within the data difference with the other references, except for the transfer coefficient. This result is useful for understanding the effectiveness of each input parameters on the simulation results.