Identifying and characterising crashes of returning riders: A new approach

Surveys have identified that many older motorcyclists are returning riders but it is difficult to draw conclusions about their crash risk because of discrepancies in definitions and the inability to identify returning riders in official crash databases. Analyses of NSW crash data were undertaken in which returning riders were defined as aged 25 and over, holding a full licence 10 years prior to the crash, and not the registered operator of one or more motorcycles during the 5-10 years prior to the crash. Based on this definition, there were 472 riders in casualty crashes in 2005-09 who were returning riders (5.5% of riders aged 25 and over in casualty crashes) and the characteristics of their crashes were similar to those involving continuing riders. In contrast, crashes of new riders were more likely to have characteristics suggestive of relatively more riding in urban areas, probably for transport rather than recreation. More work is recommended to assess the validity of the definition to allow a better understanding of the effects of long periods away from riding on riding skills and crash risk

Fracture mechanics testing for environmental stress cracking in thermoplastics

Under the combined influence of an aggressive environment and applied stress, engineering thermoplastics may undergo a phenomenon known as environmental stress cracking (ESC). This can result in adverse effects such as embrittlement and premature failure in service, due to the growth of environmentally-induced cracks to critical sizes, with little to no fluid absorption in the bulk material. Fracture mechanics is proposed as a suitable scheme to study and quantify ESC, with the aim being to obtain characterising data for different polymer-fluid combinations of interest, as well as to develop a reliable fracture mechanics test protocol. In the proposed method, slow crack growth is monitored to assess the effect of a range of applied crack driving forces (K, or alternatively G) on observed crack speeds, as opposed to simply measuring time-to-failure. This paper presents the results of experiments performed on the following materials: linear low density polyethylene (LLDPE) in Igepal solution and high impact polystyrene (HIPS) in sunflower oil. A discussion of the various issues surrounding the data analysis for these long-term tests is also included, as the attainment of consistent and repeatable results is critical for a method to be internationally standardised, which is a goal of the European Structural Integrity Society (ESIS) Technical Committee 4 from whose interest this work is drawn

Temperature effects on laminated glass at high rate

The load bearing capacity of a laminated glass pane changes with temperature. In blast protection, laminated glass panes with a Polyvinyl Butyral (PVB) interlayer are usually employed. The post-crack response of the laminated pane is determined by the interlayer material response and its bond to the glass plies. An experimental study has been performed to determine the effects of temperature on the post cracked response of laminated glass at a test rate of 1 m/s for PVB thicknesses of 0.76 mm, 1.52 mm and 2.28 mm. Tensile tests were carried out on single cracked and randomly cracked samples in a temperature range of 0 °C–60 °C. Photoelasticity observation and high speed video recording were used to capture the delamination in the single cracked tests. Competing mechanisms of PVB compliance and the adhesion between the glass and PVB, were revealed. The adhesion showed an increase at lower temperatures, but the compliance of the PVB interlayer was reduced. Based on the interlayer thickness range tested, the post-crack response of laminated glass is shown to be thickness dependent

A study on the bending of laminated glass under blast loading

Background: The bending behaviour of laminated glass plays an important role in determining its overall response to blast loading. It is costly and difficult to characterise the bending behaviour by carrying out full-scale blast tests, therefore an alternative method is required. Objective: The objective of this study is to understand the response of laminated glass under high-rate bending in the laboratory at rates representative of blast loading. Methods: In this paper a novel testing method is presented in which laminated glass strips of 700 mm long by 60 mm wide are tested up to speeds of 10 m/s in the laboratory. The laminated glass is accelerated to speeds comparable to blast loading and then brought to rest at its edges to mimic impulsive blast loading conditions. Different interlayer thickness, impact speeds, and boundary conditions were explored. Additionally, modelling methods were used to study the flexural rigidity of post-cracked laminated glass. Results: From the experiments it was found that the interlayer thickness plays a key role in determining whether the dominant failure mechanism is de-bonding of interlayer from the glass or interlayer tearing. In addition, it was found that by allowing the frame to bend under loading, the laminated glass can carry greater loads without failure. Finally, an iterative method was used to quantify the flexural rigidity of post-cracked laminated glass depending on the speed of travel. This is a novel finding as it is usually assumed that laminated glass behaves like a membrane in the post-cracked phase of the response. Conclusion: In modelling and design of laminated glass structures under blast loading, post-crack flexural rigidity must be taken into account. Additionally, having novel frame designs to add further load bearing capacity to the framing members, plays a key role in reducing the load intensity on the laminated glass structure

GP-SUM. Gaussian Processes Filtering of non-Gaussian Beliefs

This work studies the problem of stochastic dynamic filtering and state propagation with complex beliefs. The main contribution is GP-SUM, a filtering algorithm tailored to dynamic systems and observation models expressed as Gaussian Processes (GP), and to states represented as a weighted sum of Gaussians. The key attribute of GP-SUM is that it does not rely on linearizations of the dynamic or observation models, or on unimodal Gaussian approximations of the belief, hence enables tracking complex state distributions. The algorithm can be seen as a combination of a sampling-based filter with a probabilistic Bayes filter. On the one hand, GP-SUM operates by sampling the state distribution and propagating each sample through the dynamic system and observation models. On the other hand, it achieves effective sampling and accurate probabilistic propagation by relying on the GP form of the system, and the sum-of-Gaussian form of the belief. We show that GP-SUM outperforms several GP-Bayes and Particle Filters on a standard benchmark. We also demonstrate its use in a pushing task, predicting with experimental accuracy the naturally occurring non-Gaussian distributions.Comment: WAFR 2018, 16 pages, 7 figure

Cognitive Control Errors in Nonhuman Primates Resembling Those in Schizophrenia Reflect Opposing Effects of NMDA Receptor Blockade on Causal Interactions Between Cells and Circuits in Prefrontal and Parietal Cortices

Background: The causal biology underlying schizophrenia is not well understood, but it is likely to involve a malfunction in how neurons adjust synaptic connections in response to patterns of activity in networks. We examined statistical dependencies between neural signals at the cell, local circuit, and distributed network levels in prefrontal and parietal cortices of monkeys performing a variant of the AX continuous performance task paradigm. We then quantified changes in the pattern of neural interactions across levels of scale following NMDA receptor (NMDAR) blockade and related these changes to a pattern of cognitive control errors closely matching the performance of patients with schizophrenia. Methods: We recorded the spiking activity of 1762 neurons along with local field potentials at multiple electrode sites in prefrontal and parietal cortices concurrently, and we generated binary time series indicating the presence or absence of spikes in single neurons or local field potential power above or below a threshold. We then applied causal discovery analysis to the time series to detect statistical dependencies between the signals (causal interactions) and compared the pattern of these interactions before and after NMDAR blockade. Results: Global blockade of NMDAR produced distinctive and frequently opposite changes in neural interactions at the cell, local circuit, and network levels in prefrontal and parietal cortices. Cognitive control errors were associated with decreased interactions at the cell level and with opposite changes at the network level in prefrontal and parietal cortices. Conclusions: NMDAR synaptic deficits change causal interactions between neural signals at different levels of scale that correlate with schizophrenia-like deficits in cognitive control

2,4,6-Trimethyl-1,3,5-tris­(morpholino­meth­yl)benzene

In the title compound, C24H39N3O3, the H atoms of the methyl groups are disordered over two positions, with site-occupation factors fixed at 0.5. The three morpholino groups are arranged in an asymmetrical fashion with respect to the anchoring mesitylene ring and adopt chair conformations. Inter­molecular C—H⋯π inter­actions link the mol­ecules into a one-dimensional chain structure

1,3,5-Tris{[3-(1H-benzotriazol-1-ylmeth­yl)phen­oxy]meth­yl}-2,4,6-trimethyl­benzene

In the title compound, C51H45N9O3, three 1-(1H-benzotriazol-1-ylmeth­yl)-3-phen­yloxy (bmph) ligands are bonded to the central benzene ring in an asymmetric arrangement, two bmph located on one side of the central benzene ring and the other bmph located on the opposite side of the central benzene ring. The dihedral angles between the central benzene ring and the three pendant phenoxy rings are 76.71 (14), 67.81 (13) and 70.67 (16)°. In the crystal structure, one bmph is disordered over two sites in a 0.611 (5):0.389 (5) ratio. Some of the methyl H atoms are equally disordered over two sets of sites. Inter­molecular C—H⋯N hydrogen bonding is present in the crystal structure

A meeting framework for inclusive and sustainable science

The ABCD conference format (All continents, Balanced gender, low Carbon transport, Diverse backgrounds) mixes live-streamed and pre-recorded talks with in-person ones to reflect a diverse range of viewpoints and reduce the environmental footprint of meetings while also lowering barriers to inclusiveness