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

Finite Element Analysis Investigating the Sliding Contact of a Shape Memory Alloy Substrate

Recent experimental wear tests have demonstrated that shape memory alloys offer better wear resistance than conventional wear resistant materials and therefore make them ideal candidates as tribological materials. The wear resistance of shape memory alloys has been attributed to its pseudoelasticity and high yield strength. To date however, an extensive computational study that simulates the contact behavior of these alloys during a typical sliding wear process has not been investigated. This study uses the finite element method to analyze the sliding contact behavior between a rigid cylinder and a two dimensional shape memory alloy semi-infinite half-space. An experimentally validated constitutive model is used to capture the pseudoelastic effect exhibited by these alloys. The finite element contact model is validated with closed form solutions for well known normal and sliding elastic contact problems. Parametric studies involving key shape memory alloy material parameters (maximum recoverable transformation strain, the inherent difference between the elastic moduli of martensite and austenite phase, various isothermal loading paths) and coefficients of friction are conducted to study the effects on the sliding response. It is shown that the sliding response of SMAs is strongly temperature dependent, with significant residual stresses present in the half-space at temperatures below the austenitic finish temperature. An increase in the maximum transformation strain causes the stress distribution to be spread over a wider area and causes a significant decrease in the maximum von Mises stress in the half-space. The ability of shape memory alloys to undergo a stress induced transformation to a more compliant phase, also causes a reduction in the Mises stress and further demonstrates why pseudoelastic SMAs offer better wear resistance that conventional wear resistant materials

Simulating eddy current sensor outputs for blade tip timing

Blade tip timing is a contactless method used to monitor the vibration of blades in rotating machinery. Blade vibration and clearance are important diagnostic features for condition monitoring, including the detection of blade cracks. Eddy current sensors are a practical choice for blade tip timing and have been used extensively. As the data requirements from the timing measurement become more stringent and the systems become more complicated, including the use of multiple sensors, the ability to fully understand and optimize the measurement system becomes more important. This requires detailed modeling of eddy current sensors in the blade tip timing application; the current approaches often rely on experimental trials. Existing simulations for eddy current sensors have not considered the particular case of a blade rotating past the sensor. Hence, the novel aspect of this article is the development of a detailed quasi-static finite element model of the electro-magnetic field to simulate the integrated measured output of the sensor. This model is demonstrated by simulating the effect of tip clearance, blade geometry, and blade velocity on the output of the eddy current sensor. This allows an understanding of the sources of error in the blade time of arrival estimate and hence insight into the accuracy of the blade vibration measurement

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

A systematic investigation of relevant predictors, moderations and mediations for intention to speed, drink-drive, drive while fatigued, and not wear a seat belt, amongst young NSW drivers

Road trauma is recognized as a major public health problem worldwide (particularly for younger drivers), and risky driving has been identified as an important contributor to road crashes. It is often assumed that similar factors influence all risky driving behaviours, although direct and systematic examination of the differences between risky driving behaviours in terms of precipitating factors is lacking. The present thesis sought to undertake a systematic investigation of relevant factors in the prediction of four key risky driving behaviours (speeding, drink-driving, driving while fatigued, and not wearing seat belts).Four versions of a Risky Driving Questionnaire were developed to assess beliefs, personality factors and behavioural intentions, in relation to each of the four behaviours. Four versions of the Implicit Association Test were developed to assess attitudes toward each of the four behaviours, without reliance on self-report (in terms of the relative strength of pairs of associations). Data were collected from a student sample (N=215: Study 1), as well as urban (N=587) and rural (N=422) general population samples (Study 2), and regression models were examined for each of the four behaviours, with interaction terms to assess moderations involving perceived risk. Mediations involving gender were also assessed.Results indicate that different risky driving behaviours are predicted by different factors. For example, in the urban sample, speeding was predicted by driver anger and illusory invulnerability, drink driving was predicted by peer influence, driving while fatigued was predicted by the perceived benefits of not driving while fatigued, and not wearing seat belts was predicted by the (sensation seeking x illusory invulnerability) interaction. Results also suggest that different predictors of risky driving behaviours are relevant for different driver populations. For example, speeding was predicted by authority rebellion in the urban sample, and by sensation seeking in the rural sample. Observed moderations of perceived risk suggest that relationships between perceived risk and risky driving may differ for males versus females, and for low versus high sensation seekers. Findings suggest that future road safety interventions should be based on research of the determinants of individual risky driving behaviours, and in specific driver populations