Droplet Impact on Dry, Superhydrophobic Surfaces with Micro-Scale Roughness Elements

Most aircraft accidents are caused by technical problems or weather-related issues. One cause of weather-related incidents is inlight icing, which can induce negative performance characteristics and endanger the operation of an airplane. Various researchers investigating the problem of inlight icing have proposed ice-phobic coatings as one viable solution. For this purpose, it is critical to study the behavior of a droplet impact on different types of surfaces. As an alternative to physical testing, three-dimensional numerical simulation using computational fluid dynamics offers a promising strategy for evaluating the effects of surface characteristics. Using the volume of fluid method, three simulations of high-speed droplet impact on superhydrophobic surfaces with and without micro-scale roughness elements, were generated. The simulations showed that, for the roughness configurations considered, the superhydrophobic surfaces with micro-scale roughness elements were significantly less effective at repelling the droplet than the smooth superhydrophobic surfaces

Deep Reinforcement Learning for Complete Coverage Path Planning in Unknown Environments

Mobile robots must operate autonomously, often in unknown and unstructured environments. To achieve this objective, a robot must be able to correctly perceive its environment, plan its path, and move around safely, without human supervision. Navigation from an initial position to a target lo- cation has been a challenging problem in robotics. This work examined the particular navigation task requiring complete coverage planning in outdoor environments. A motion planner based on Deep Reinforcement Learning is proposed where a Deep Q-network is trained to learn a control policy to approximate the optimal strategy, using a dynamic map of the environment. In addition to this path planning algorithm, a computer vision system is presented as a way to capture the images of a stereo camera embedded on the robot, detect obstacles and update the workspace map. Simulation results show that the algorithm generalizes well to different types of environments. After multiple sequences of training of the Reinforcement Learning agent, the virtual mobile robot is able to cover the whole space with a coverage rate of over 80% on average, starting from a varying initial position, while avoiding obstacles by using relying on local sensory information. The experiments also demonstrate that the DQN agent was able to better perform the coverage when compared to a human

Helmets for preventing injury in motorcycle riders

Background: Motorcycle crash victims form a high proportion of those killed or injured in road traffic accidents. Injuries to the head, following motorcycle crashes, are a common cause of severe morbidity and mortality. It seems intuitive that helmets should protect against head injuries but it has been argued that motorcycle helmet use decreases rider vision and increases neck injuries. This review will collate the \u27current available evidence on helmets and their impact on mortality, and head, face and neck injuries following motorcycle crashes.Objectives: To quantify the effectiveness of wearing a motorcycle helmet in reducing mortality and head and neck injury following motorcycle crashes.Search strategy: Databases including the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library issue 1,2003), MEDLINE (January 1966 to February 2003), EMBASE (January 1985 to February 2003), CINAHL (January 1982 to February 2003), IRRD (International Road Research Documentation), TRANSDOC, TRIS (Transport Research Information Service), ATRI (Australian Transport Index) (1976 to Feb 2003), Science Citation Index were searched for relevant articles. Web sites of traffic and road accident research bodies including government agencies were also searched. Reference lists from topic reviews, identified studies and bibliographies were examined for relevant articles.Selection criteria: We considered for inclusion studies that investigated a population of motorcycle riders who had crashed, examining helmet use as an intervention and with outcomes that included one or more of the following: death, head, neck or facial injury. Studies included any that compared an intervention and control group and, therefore, included any randomised controlled trials, non-randomised controlled trials, cohort, case-control and cross-sectional studies. Ecological and case series studies were excluded.Data collection and analysis: Two reviewers independently screened reference lists for eligible articles. Two reviewers independently assessed articles for inclusion criteria. Data were abstracted by two independent reviewers using a standard abstraction form.Main results: Fifty-three observational studies were identified of varying quality. Despite methodological differences there was a remarkable consistency in results, particularly for mortality and head injury outcomes. Motorcycle helmets appear to reduce the risk of mortality although, due to heterogeneity in study design, an overall estimate of effect was not calculated. There was some evidence that the effect of helmets on mortality is modified by speed. Motorcycle helmets were found to reduce the risk of head injury and from five well-conducted studies the risk reduction is estimated to be 72% (OR 0.28, 95%CI 0.23,0.35). Insufficient evidence was found to estimate the effect of motorcycle helmets compared with no helmet on facial or neck injuries. However, studies of poorer quality suggest that helmets have no effect on the risk of neck injuries and are protective for facial injury. There was insufficient evidence to demonstrate whether differences in helmet type confer more or less advantage in injury reduction.Conclusions: Motorcycle helmets reduce the risk of mortality and head injury in motorcycle riders who crash, although the former effect may be modified by other crash factors such as speed. Further well-conducted research is required to determine the effects of helmets and different helmet types on mortalIty, head, neck and facial injuries. However, the findings suggest that global efforts to reduce road traffic injuries may be facilitated by increasing helmet use by motorcyclists.<br /

Reported changes in cycling habits among older adults during the early months of the COVID-19 pandemic, New South Wales, Australia

The im.pact of the 2020 COVID-19 pandemic and the associated public health measures enacted by governments globally bad a significant impact on all aspects of human life including economic activity and mobility. One of the main public health measures designed to reduce the transmission of the SAR-Co V-2 vims have been the implementation ofvarious levels of lockdowns that limited mobility and resulted in almost half of the world's population UD.der som.e form of confinement. Many govemm.ents, including in Australia, UK, and Norway, enacted flexible forms oflockdowns that allowed daily outdoor exercise, while adhering to safe physical distancing, in recognition of the role of physical activity in reducing the mental and physical consequences of confinement. Australia saw first strict lockdown restrictions over March/April 2020 with progressive easing of restrictions during May and Ju.ne 2020. Emerging evidence from these countries has indicated that physical activity, particularly cycling, increased over the lockdown period and the following months as some restrictions were eased. However, many have wamed of a decline in physical activity with serious health consequences among older adults who were at a high.er risk: of m.orbidity and fatality associated with COVID-19 and were m.ore likely tobe confined to their homes for longer periods compared to younger age groups. The aim ofthis stu.dy was to investigate the impact ofCOVID-19 pandemic on cycling activity among older adults aged 50 years and over in New South Wales (NSW), Australia during the early months of the COVID-19 pandemic

Use of caffeinated substances and risk of crashes in long distance drivers of commercial vehicles: case-control study

Objective: To determine whether there is an association between use of substances that contain caffeine and the risk of crash in long distance commercial vehicle drivers.Design: Case-control studySetting: New South Wales (NSW) and Western Australia (WA), Australia.Participants: 530 long distance drivers of commercial vehicles who were recently involved in a crash attended by police (cases) and 517 control drivers who had not had a crash while driving a commercial vehicle in the past 12 months.Main outcome measure: The likelihood of a crash associated with the use of substances containing caffeine after adjustment for factors including age, health disorders, sleep patterns, and symptoms of sleep disorders as well as exposures such as kilometres driven, hours slept, breaks taken, and night driving schedules.Results: Forty three percent of drivers reported consuming substances containing caffeine, such as tea, coffee, caffeine tablets, or energy drinks for the express purpose of staying awake. Only 3% reported using illegal stimulants such as amphetamine (“speed”); 3,4 methylenedioxymethamphetamine (ecstasy); and cocaine. After adjustment for potential confounders, drivers who consumed caffeinated substances for this purpose had a 63% reduced likelihood of crashing (odds ratio 0.37, 95% confidence interval 0.27 to 0.50) compared with drivers who did not take caffeinated substances.Conclusions: Caffeinated substances are associated with a reduced risk of crashing for long distance commercial motor vehicle drivers. While comprehensive mandated strategies for fatigue management remain a priority, the use of caffeinated substances could be a useful adjunct strategy in the maintenance of alertness while driving

Risky youth to risky adults: Sustained increased risk of crash in the DRIVE study 13 years on.

The objective of this study was to investigate if drivers who exhibit risky driving behaviours during youth (aged 17-24 years) have an increased risk of car crash up to 13 years later. We used data from the DRIVE study, a 2003/04 survey of 20,806 young novice drivers in New South Wales, Australia. The data were linked with police crash, hospital and deaths data up to 2016. We analysed differences in crash associated with 13 items of risky driving behaviours using negative binominal regression models adjusted for driver demographics, driving exposure and known crash risk factors. The items were summarised in one index and grouped into quintiles for the analysis. After adjusting for confounding, drivers of the third (RR 1.16, 95% CI 1.05-1.30), fourth (RR1.22, 95% CI1.09-1.36) and fifth quintile (RR 1.36, 95% CI 1.21-1.53) had higher crash rates compared to the lowest risk-takers. Drivers with the highest scores on the risky driving measure had higher rates of crash related hospital admission or death (RR 1.92, 95% CI 1.13-3.27), crashes in wet conditions (RR 1.35,95% CI 1.05-1.73), crashes in darkness (RR 1.55, 95% CI 1.25-1.93) and head-on crashes (RR 2.14, 95% CI 1.07-4.28), compared with drivers with the lowest scores. Novice adolescent drivers who reported high levels of risky driving when they first obtained a driver licence remained at increased risk of crash well into adulthood. Measures that successfully reduce early risky driving, have the potential to substantially reduce road crashes and transport related injuries and deaths over the lifespan

Increase in fall-related hospitalizations in the United States, 2001-2008

BACKGROUND: The objective was to determine secular trends in unintentional fall-related hospitalizations in people aged 65 years and older in the United States. MATERIALS: Data were obtained from a nationally representative sample of emergency department visits from January 1, 2001, to December 31, 2008, available through the National Electronic Injury Surveillance System-All Injury Program. These data were weighted to estimate the number, incidence rates, and the annual percent change of fall-related hospitalizations. RESULTS: From 2001 to 2008, the estimated number of fall-related hospitalizations in older adults increased 50%, from 373,128 to 559,355 cases. During the same time period, the age-adjusted incidence rate, expressed per 100,000 population, increased from 1,046 to 1,368. Rates were higher in women compared with men throughout the study period. The age-adjusted incidence rate showed an average annual increase of 3.3% (95% CI, 1.66-4.95). DISCUSSION: Both the number and rate of fall-related hospitalizations in the United States increased significantly over the 8-year study period. Unless preventive action is taken, rising hospitalization rates in combination with the aging US population over the next decades will exacerbate the already stressed healthcare system and may result in poorer health outcomes for older adults in the future. Further research is needed to determine the underlying causes for this rising trend. Copyrigh

Driving offences and risk of subsequent crash in novice drivers: the DRIVE cohort study 12-year follow-up

Background Penalties are a key component to improve road user safety, but previous studies suggested that they might not be successful in reducing crashing in offending drivers. However, these studies were not able to consider important crash risk factors in the analysis that might confound the results. Using data from a large prospective cohort study of young drivers in New South Wales, Australia, we explored if novice drivers with driving offences have a higher rates of car crash and if these differences are explained by established crash risk factors. Methods We used data from a 2003/2004 Australian survey of young drivers, linked to police reported offence and crash data, hospital data and deaths data up to 2016. We used Poisson regression models adjusted for confounders to estimate the association between driving offences during 2003–2006 with car crash during 2007–2016. Results The study cohort comprised 20 781 young drivers of whom 7860 drivers (37.8%) had at least one driving offence and 2487 (12.0%) were involved in at least one crash. After adjusting for confounders in the regression model, drivers with three or more driving offences had 2.25 (95% CI 1.98 to 2.57), 2.87 (95% CI 1.60 to 5.17) and 3.28 (95% CI 2.28 to 4.72) times higher rates of any crash, crashes that resulted in hospital admission or death and single vehicle crashes compared with drivers with no driving offences. Conclusion Measures that successfully mitigate the underlying risk factors for both, crashes and offences, have the potential to improve road safety