Dynamic simulation of collisions of heavy high-speed trucks with concrete barriers

Real vehicle collision experiments on full-scale road safety barriers are important to determine the outcome of a vehicle versus barrier impact accident. However, such experiments require large investment of time and money. Numerical simulation has therefore been imperative as an alternative method for testing concrete barriers. In this research, spring subgrade models were first developed to simulate the ground boundary of concrete barriers. Both heavy trucks and concrete barriers were modeled using finite element methods (FEM) to simulate dynamic collision performances. Comparison of the results generated from computer simulations and on-site full-scale experiments demonstrated that the developed models could be applied to simulate the collision of heavy trucks with concrete barriers to provide the data to design new road safety barriers and analyze existing ones.

Speed of adjustment within currency markets

One measure of market efficiency is the speed at which prices adjust to fundamental value with the arrival of information. This paper examines this issue by estimating speed of adjustment coefficients using three  methodologies for eight currencies for the entire year of 1996 using half hourly non-overlapping return intervals. We find that the bulk of adjustment to fundamental value for all currencies occurs within the hour but then quickly deteriorates. Within the hour adjustment is sufficiently quick to be considered efficient but the lack of full adjustment to fundamental value is not what would be predicted within an efficient market. There is no evidence for any of the currencies studied of a tendency to over react. There is also little difference in the speeds of adjustment between actively and less actively traded  currencies. There is however a definite difference in the speed at which currencies adjustment depending on whether they are free floating or managed exchange rates. Free floating rates adjust much quicker. Government intervention slows adjustment to fundamental value.

Not just for romance: applications of speed dating in social work education

In this article we address how a contemporary adaptation of the 'speed dating' model was used for educational purposes with two cohorts of social work students. We outline the dimensions of 'speed dating' as a contemporary social phenomenon, then address how this model relates specifically to groupwork process, and can be used to facilitate social work student learning. The curriculum for two classroom group activities using the 'speed dating' model are outlined, the first to develop university level study skills, the second for debriefing field placement learning experiences. Finally we examine why the 'speed dating' metaphor was successful in provoking a playful yet constructively creative space for students to engage in groupwork process.

Modelling factors of square tubes in high speed bending situations

Accurate finite element crash simulations of side impact depend upon a thorough understanding of dynamic tube bending. There is a need to understand the dynamic bending mode of square sections (equivalent of automotive structural parts) to obtain a greater confidence in CAE. This work varied strain rate and material definitions, such as Cowper-Symonds vs Zerilli-Armstrong, as well as initial velocity and yield strength. The results show that most of the plastic work is done between strains rates of 30 ¿ 300/s and strains up to 0.3. Peak strain rates were marginally above 1000/s with maximum strain greater than 1. When the strain rate definition and material model were modified, it was shown that a higher yield stress produced a higher reaction force. These results would suggest that the strain rate sensitivity needs to be carefully identified for accurate crash simulations.

Age and walking speed effects on muscle recruitment in gait termination

During gait termination at normal walking speed, older adults more frequently employ two-step responses, increasing their stopping distance and stopping time more than younger controls. This study investigated ageing effects on lower limb muscle recruitment patterns during stopping at three walking speeds. Twelve young male (26±3.7 years, range 19–30) and 12 gender-matched older participants (72±4.3 years, range 65–82) terminated walking at normal, medium and maximum speed. A visual stopping stimulus was presented 10 ms following either left or right heel-contact with no stimulus (catch) on 30% of trials. Electromyographic (EMG) activity was recorded from the tibialis anterior (TA), soleus (SOL), biceps femoris (BF), vastus lateralis (VL) and gluteus medius (GM). Older males more frequently (46% of trials) took two-steps to stop than young males (20%). The stance leg muscles responded significantly faster than the swing leg, and with increased speed, fewer swing limb muscles contributed to stopping. Older males were slower to respond with the stance leg, at 215 ms following the stimulus compared with 176 ms for the younger group. They also recruited fewer swing leg muscles with less frequent activation of the soleus and gluteus medius. Failure to activate muscles would provide less extensor torque to maintain the centre of gravity anterior to the forward base of support. This would decrease the total force opposing horizontal velocity in order to bring the body to rest and, as a consequence, encourage an additional step prior to stopping.

'Horses for courses' - curriculum-speed in the CSF

This article considers the issue of acceleration in lower secondary school mathematics in the Victorian Curriculum and Standards Framework.

Do organizational service recovery actions impact on hotel guests future intentions and does speed of recovery matter?

This paper investigates hotel guests’ responses to organizational actions dealing with service failure. Eight service failure scenarios were used to identify guests’ intentions towards future visits. Guests’ intentions to switch hotels, revisit the property and remain loyal to the chain were found to vary based on the recovery efforts undertaken. This research found that empowering employees contribute to positive consumer intentions toward the service provider. Compensation was also found effective if offered through empowered employees. Speed of response to service failure was also identified as important action to improve consumer future intentions. Based on these findings, implications for future research are highlighted. Recommendations to the practitioners of hospitality and tourism sector were made for the management of failed service encounter.

Role of organizational service recovery actions on sustomer switching intentions in a process based service failure : does speed of recovery matters?

The study examines how organizational activities of compensation and empowerment impact on consumers switching intentions and also whether these differ based on the speed of service recovery. Data is collected using hypothetical scenarios in a situation of process failure. It is found that there is no direct effect of either compensation or empowerment on switching intent, although the interaction effect is significant when recovery occurs quickly.

Need for speed

Like me you probably read a few magazines, including PC Update, and Google your way around the Web before launching into any complex endeavour involving PC or network updates. This is particularly the case when it comes to any serious expenditure. I'll be honest; sometimes I read the reviews after the fact, just as I sometimes read the instructions after an installation goes pear-shaped. This How-To is one of those experiences.

Reviving growth in the Fiji islands : are we swimming or sinking?

The Fiji government’s 2008 'budget for hope' rests on some fundamental assumptions: political stability, the recovery of key sectors of the economy from the effects of the 2006 coup, as well as the recovery of the tourism industry, an industry which in the past has been resilient to coups. With 34 per cent of the population already living below the poverty line, low economic growth could push significantly more people into poverty. If the increases in global food and fuel prices persist, creating even more difficulties for the poor, the prospect of social instability could heighten. In the absence of the expected recovery of these key sectors and the loss of skilled workers, achieving economic and social recovery will require political consensus to resolve the political impasse that has gripped the country. The Interim Government also needs to revisit its fiscal austerity package.

Energy efficient, fully-connected mesh networks for high speed applications

Fully-connected mesh networks that can potentially be employed in a range of applications, are inherently associated with major deficiencies in interference management and network capacity improvement. The tree-connected (routing based) mesh networks used in today’s applications have major deficiencies in routing delays and reconfiguration delays in the implementation stage. This paper introduces a CDMA based fully-connected mesh network, which controls the transmission powers of the nodes in order to ensure that the communication channels remain interference-free and minimizes the energy consumption. Moreover, the bounds for the number of nodes and the spatial configuration are provided to ensures that the communication link satisfies the QoS (Quality of Service) requirements at all times.

Analysis and implementation of swimming backward for biomimetic carangiform robot fish

The swimming backward for biomimetic carangiform robot fish is analyzed and implemented in this paper. The swimming law of the carangiform robot fish is modified according to the European Eel swimming mode based on the multiple-link structure to implement the backward motion. The motion mode difference between the eel and carangiform fish is discussed, and a qualitative kinematic analysis of the carangiform swimming in water is given to analyze the propulsion produced by the undulation of the multi-links tail. The experiments conducted demonstrate the good performance of the proposed method, and the results are given.