An objective measure to quantify discomfort in long duration driving

In recent years increased emphasis has been placed on improving seat comfort in automobiles. This is partly due to research showing that prolonged driving is associated with increased risk of musculoskeletal disorders, but largely because driver comfort is now viewed as an increasingly important aspect of the competitive marketing of vehicles. Driving is firmly cemented as a major part of most people s daily life across the world and people are now spending more time in their vehicles than ever before. As urban congestion continues to rise, commuting distances and durations will progressively increase, subjecting drivers to the risks of long duration driving more often. Consequently the automotive industry has invested in designing seats that perform better under increased usage durations and ergonomics has played a vital role in the design of new seats. However, the ability to design a successful seat relies heavily on the capacity to accurately evaluate the comfort of a vehicle seat and one major issue that has been highlighted with the current state of automotive ergonomics research is the standardisation of comfort evaluation techniques. This research aimed to tackle these issues by investigating the effects of long duration driving on discomfort and the range factors associated with driver discomfort. Furthermore, the ultimate goal of this research was develop and evaluate a novel objective measure of driver discomfort that focused on driver seat fidgets and movements (SFMs) with the aim of standardising discomfort evaluation within the automotive industry. Three laboratory studies and one field observation were conducted to address these aims whereby subjective and objective evaluations of discomfort were conducted during long term driving (ranging from 60 - 140 minutes). The results determined that a measure of driver SFMs can be effectively implemented into long duration driving trials to evaluate the effects of long term driving and vibration exposure on driver discomfort and subsequently used to make accurate predictions of overall discomfort. Large positive correlations have been determined between measures of SFMs and subjective ratings of overall discomfort (r2 > 0.9, P < 0.05) and the SFM method has been successfully repeated under a range of driving conditions. Driver seat fidget and movement (SFM) frequency is shown to significantly increase congruently with subjective ratings over the duration of a long term drive as drivers seek to cope with increased discomfort. It is proposed that drivers will record movements in the vehicle seat when discomfort reaches a threshold that is consciously or unconsciously perceived and as the duration of driving accrues, drivers will reach this threshold with increased frequency. A measure of both SFM frequency and total accumulative SFMs have been shown to accurately predict discomfort ratings and provides the basis for discomfort evaluations to be made via remote monitoring, removing the need for subjective assessment. During a long term drive, there becomes a point upon which improvements in seat design become ineffective as extended duration driving will result in discomfort regardless of how well the seat has been designed. It was shown that drivers will move in the vehicle seat to cope with increased discomfort and in addition, another method of combatting the negative effects of long term driving was investigated. Subjective and objective evaluation determined that breaks from driving will reduce discomfort both immediately and upon completion of a long term drive. Furthermore, these benefits were increased when drivers left the vehicle seat as discomfort was reset when drivers took a 10 minute walk. Walking during a break from driving can be considered the ultimate SFM. Drivers are recommended to plan breaks from driving when conducting a long duration journey in order to minimise discomfort and when taking a break, drivers should take a walk rather than remain seated in the vehicle

Temperature and pore pressure effects on the shear strength of granite in the brittle-plastic transition regime

Currently published lithospheric strength profiles lack constraints from experimental data for shear failure of typical crustal materials in the brittle-plastic transition regime in wet environments. Conventional triaxial shear fracture experiments were conducted to determine temperature and pore pressure effects on shear fracture strength of wet and dry Tsukuba granite. Experimental conditions were 70MPa < P-C < 480MPa, 10MPa < P-p < 300MPa, 25 A degreesC < T < 480 degreesC, at a constant strain rate of 10(-5)s(-1). An empirical relation is proposed which can predict the shear strength of Tsukuba granite, within the range of experimental conditions. Mechanical pore pressure effects are incorporated in the effective stress law. Chemical effects are enhanced at temperatures above 300 degreesC. Below 300 degreesC wet and dry granite strengths are temperature insensitive and wholly within the brittle regime. Above 400 degreesC, semi-brittle effects and ductility are observed

Climate change driven disaster risks in Bangladesh and its journey towards resilience

Globally, disasters from natural and anthropogenic hazards or humanitarian crises can reverse development gains and weaken resilience. In recent years, some countries have made significant progress towards building resilience to disaster risks, including those driven by the climate crisis. Bangladesh is a leading example as it is well-known as one of the most vulnerable countries for its multifaceted hazard risks projected to intensity under climate change. Today, the scale of loss of human life from both rapid and slow-onset disasters (e.g. cyclone, flood and drought) is significantly lower than in the 1970s. This remarkable achievement was made possible by independence and the government’s proactive investment in development and societal changes through education, technologies and reduction in poverty and inequalities. However, the climate crisis is threatening these development and disaster risk reduction gains. In addition, disaster displacement is a major challenge. The COVID-19 pandemic has unveiled both strengths and weaknesses in our societies. The article argues that disaster management plans need to adapt to the climate crisis and human displacement and reduce migrants’ vulnerability while responding to infectious disease transmission

Water sharing for the environment and agriculture in the Broken catchment

The Commonwealth of Australia Water Act 2007 changed the priority for water use in the Murray-Darling Basin (MDB) to first ensure environmentally sustainable levels of extraction and then to maximise net economic returns to the community from water use. The Murray- Darling Basin Authority (MDBA) is expected to deliver a draft Basin Plan in 2011 providing a framework for future water planning. The Plan will include Sustainable Diversion Limits (SDLs) which define water diversions for consumption while maintaining environmental assets and ecosystem functions. The 2009 MDBA Concept Statement acknowledged that in some areas less information is available to determine the SDLs. The 2010 MDBA Guide to the Basin Plan proposed SDLs reducing the current long-term average surface water diversions to between 25 and 34% for the Goulburn-Broken region. Representative farm-level models of irrigated dairy, horticulture and viticulture, and dryland broadacre, industries were developed to determine the likely impacts on farm income and farm enterprise mix if the price and quantity of irrigation water changes. Water for ecological benefits and ecosystem functioning was determined for a range of river health levels using a bottom-up approach identifying flow requirements for fish, riparian vegetation, invertebrates, and geomorphic and nutrient processes. A novel part of the analysis is the conjunctive use of water for both purposes, e.g. wetland filling and then pumping for irrigation. The linkages between changed land use and surface/ground water outcomes are assessed using a Catchment Analysis Tool. An experimental design of different proportions of water going to the environment and consumptive uses showed potential trade-offs between agricultural, environmental and surface/ground water outcomes. These trade-offs were examined to assess the impact of alternative water management on catchment welfare, and provide information about setting SDLs.Water sharing, environment, agriculture, Murray-Darling Basin, Broken catchment, Resource /Energy Economics and Policy, Q18, Q25, Q28,

Evolution of microseismicity during frictional sliding

We have done frictional sliding experiments on Inada granite in double shear and monitored the acoustic emission (AE) produced and temporal changes in the microseismic b-value (where b is defined as the log-linear slope of the AE frequency-amplitude distribution), using both rough and smooth ground simulated fault surfaces. We have found, (i) the maximum amplitudes of AE events during stable sliding are strongly dependent on the surface roughness with smooth-ground surfaces giving smaller maximum AE amplitudes; (ii) b-values are related to the surface topographic fractal dimensions, so that in steady-state stable sliding smooth surfaces exhibit lower b-values than rough surfaces; (iii) the b-value falls before stick-slip instability. The change of b with slip we interpret in terms of evolving fractal crack damage during frictional sliding of the fault surfaces

Improving long term driving comfort by taking breaks - how break activity affects effectiveness

During long duration journeys, drivers are encouraged to take regular breaks. The benefits of breaks have been documented for safety; breaks may also be beneficial for comfort. The activity undertaken during a break may influence its effectiveness. Volunteers completed 3 journeys on a driving simulator. Each 130 min journey included a 10 min break after the first hour. During the break volunteers either stayed seated, left the simulator and sat in an adjacent room, or took a walk on a treadmill. The results show a reduction in driver discomfort during the break for all 3 conditions, but the effectiveness of the break was dependent on activity undertaken. Remaining seated in the vehicle provided some improvement in comfort, but more was experienced after leaving the simulator and sitting in an adjacent room. The most effective break occurred when the driver walked for 10 min on a treadmill. The benefits from taking a break continued until the end of the study (after a further hour of driving), such that comfort remained the best after taking a walk and worst for those who remained seated. It is concluded that taking a break and taking a walk is an effective method for relieving driving discomfort