Infiltration behaviour of water in a carbon nanotube under external pressure

The wetting behaviour and associated pressure effect of water in single-walled carbon nanotubes (SWCNTs) are investigated through molecular dynamics (MD) simulations. It is found that water molecules can enter SWCNTs via surface diffusion, and the effective infiltration rate increases with pressure. The effect of pressure on infiltration rate is highly non-linear, exhibiting characteristics of both hydrophilic and hydrophobic surfaces. There exists a nominal infiltration pressure that is dependent on the SWCNT size, above which the water flux is significantly increased.     

Scaling relationships in indentation of power-law creep solids using self-similar indenters

We use dimensional analysis to derive scaling relationships for self-similar indenters indenting solids that exhibit power-law creep. We identify the parameter that represents the indentation strain rate. The scaling relationships are applied to several types of indentation creep experiment with constant displacement rate, constant loading rate or constant ratio of loading rate over load. The predictions compare favourably with experimental observations reported in the literature. Finally, a connection is found between creep and 'indentation-size effect' (i.e. changing hardness with indentation depth or load).     

Phase-field crystal modeling of anisotropic material systems of arbitrary Poisson's ratio

Recently, we derived a generalized model for isotropic as well as anisotropic crystal lattice systems of arbitrary Poisson's ratio within the framework of the continuum phase-field crystal (PFC) approach [R. Prieler, J. Hubert, D. Li, B. Verleye, R. Haberkern, H. Emmerich, J. Phys.: Condens. Matter 21 (2009) p.464110] and showed how its parameters can be derived from classical density functional theory [M.A. Choudhary, D. Li, H. Emmerich and H. Löwen, J. Phys.: Condens. Matter 23 (2011) p.265005]. Here, we present a general procedure to model anisotropic material systems of arbitrary Poisson's ratios. In that way we can for the first time identify PFC solutions of arbitrary Poisson's ratios and thereby extend the applicability of the PFC method to a larger class of material systems.     

Many-body potential for nitrogen in α-iron

N atom is one of the most frequent foreign interstitial atoms in α-iron along with C atoms. The Fe–C potential has been well-developed and can reproduce many significant interactions of C with point defects present in α-iron. However, there exists no satisfactory Fe–N potential to describe the interactions of N with point defects. Here, we develop a many-body potential for N in α-iron. The potential parameters are determined by fitting to ab initio data, which includes energetics, configurations, and relaxations of Fe atoms close to N atom. This potential successfully describes the interactions of Fe–N across a wide range of defect environments. The potential employs the embedded atom method form and hence is appropriate for large-scale molecular dynamics simulation.     

Is the future always brighter than the past? Anticipation of changes in the personal future after recall of past experiences

People tend to hold an optimistic view of their futures. Using a novel paradigm to examine the anticipated change from the personal past to the personal future, we found that the future was not always perceived as brighter than the past. College students (N = 156) recalled positive and negative personal events of various situations. Following each recall, they imagined a future personal event involving the same situation. Participants expected over half of the events to change in either upward or downward directions, depending on the valence of the past events. In addition, participants anticipated greater changes in domains of less stability, and Asians anticipated greater changes than European Americans. Anticipated future changes were further associated with psychological well-being. The findings shed new light on future event simulation.     

The antecedents of anticipatory purchase: Reconciling the two routes to optimism

Consumers often behave optimistically, purchasing products that they are unable to use at the time of purchase, but anticipate being able to use in the future. This research investigates such anticipatory purchase behavior, and demonstrates that optimism exerts its influence on anticipatory purchase via two distinct routes. One is driven by the perceived ease of the process required to achieve a given outcome and prevails when sufficient cognitive resources are available, while the other is driven directly by the perceived favorability of the outcome itself and holds when cognitive resources are constrained. Within each route, the focus of thought (process vs. outcome-focus) moderates the influence of optimism, and the two routes converge on enhanced motivation. Multiple experiments provide support for predictions derived from this framework, illuminating the substantive domain of anticipatory purchasing and providing theoretical insights into the nature of optimism.     

Distraction while driving: The case of older drivers

As the impairment of older drivers is especially found in perception and attention, one could assume that they are especially prone to distraction effects of secondary tasks performed while driving. The aim of the study was to examine the effect of age on driving performance as well as the compensation strategies of older drivers under distraction. 10 middle-aged and 10 older drivers drove in a simulator with and without a secondary task. To assess driving performance the Lane Change Task (Mattes, 2003) was used. This method aims at estimating driver demand while a secondary task is being performed, by measuring performance degradation on a primary driving-like task in a standardized manner. The secondary task – a self-developed computer-based version of “d2 Test of Attention” was presented both with and without time pressure. The results show that older participants’ overall driving performance (mean deviation from an ideal path) was worse in all conditions as compared to the younger ones. With regard to lane change reaction time both age groups were influenced by distraction in a comparable manner. However, when the lane keeping performance (standard deviation of the lateral position) was examined, the older participants were more affected than the younger ones. This pattern could be explained by compensation strategies of the older drivers. They focused on the most relevant part of the driving task, the lane change manoeuvres and were able to maintain their performance level in a similar way as did younger drivers. The driving performance of the older participants was not additionally impaired when the secondary task imposed time pressure. Overall, subjective rating of driving performance, perceived workload and perceived distraction was found to be similar for both age groups. The observed trends and patterns associated with distraction while driving should contribute to the further research or practical work regarding in-vehicle technologies and older drivers.     

Driver responses to motorcycle and lead vehicle braking events: The effects of motorcycling experience and novice versus experienced drivers

In many countries, motorcyclists are over-represented in traffic collision fatalities and injuries compared to vehicle registrations. Why drivers may violate the right-of-way of motorcyclists traveling as lead vehicles in front of drivers is empirically examined in two studies that were conducted with a moderate-fidelity driving simulator. The purpose of the first study was to determine if drivers, who also held a motorcycle license (N = 16), drove cars differently than regular drivers (N = 16) around motorcycles. The two groups did not differ on responses to motorcycling braking events, which was consistent with previous research on car following. The second study compared the driving performance of sixteen novice teenage drivers (M = 16.2 years of age) to 15 experienced drivers (M = 32.9) over the span of six monthly simulator sessions. Novice drivers’ perception response times (PRT) to the braking events were significantly longer than those of the experienced drivers. PRTs to motorcycle and lead vehicle braking events decreased over sessions. For all participants, PRTs to the motorcycle events were longer than to the car events. The implications of these results for motorcyclists and drivers with different levels of experience are discussed.     

心理模拟在语言理解中的作用

心理模拟在语言理解中的作用逐渐受到人们重视。相关理论包括知觉符号系统理论、语言的神经理论和语言与情境模拟理论。行为研究发现感知觉运动信息与语言理解存在交互作用,而脑机制研究显示感知觉运动脑区参与语言理解。目前的研究对于心理模拟参与语言理解的机制仍缺乏细致探讨,导致结果存在矛盾之处。对隐喻语言里心理模拟作用的探讨也需加强。此外,心理模拟系统如何与语言学信息交互作用的相关假设也需要完善。     

FREE WILL ACCORDING TO JOHN DUNS SCOTUS AND NEUROSCIENCE

Abstract. This paper examines two views of free will. It looks first at the fourteenth‐century religious insights of John Duns Scotus, one of history's seminal thinkers about free will. It then examines what current neuroscience tells us about free will. Finally, it summarizes the past and present views and concludes by answering two questions: Does free will refer to an absence of external constraint, or does it refer to a human ability to decide in an acausal manner?