2,894 research outputs found

    Military helicopters: have the seeds of future accidents already been sown?

    No full text
    Military helicopters provide ideal conditions for the nucleation and propagation of failure damage. Very few modern machines are expected to perform under such diverse loading and environmental conditions. It is often assumed that failures are a direct consequence of these extreme operating conditions. This paper aims to demonstrate that the originating causes of failure can be introduced at any point in the life of a component, including the design, materials processing, manufacturing or during the service life of the component. Solutions to prevent recurrence of problems cannot be developed without identification of the root cause. Details of four investigations will be presented. Each case study will demonstrate a physical cause residing in an action/inaction occurring during one (or more) of the key life stages of a component, Design, Processing, Manufacture and Service

    Real-time on-board condition monitoring of train axle bearings

    No full text
    Premature failure of rail axle bearings causes a significant increase in train operating costs and can impact train safety. A new on-board condition monitoring approach provided by Perpetuum Ltd is fitted on passenger trains to provide the operator with real-time information on bearing health. This new technology allows the detection of early bearing damage.This paper reports an initial study to understand the source of vibrations. The final aim of the project is to connect the increasing vibration data to the bearing surface damage, measured with surface profilometr

    Improving indoor thermal comfort, air quality and the health of older adults through environmental policies in London

    Get PDF
    In this work we evaluate the potential of selected environmental strategies in reducing air pollution and summertime indoor overheating. Associated changes in mortality rates are also calculated for older adults in London. Reducing these risks for vulnerable groups is an immediate priority and given that seniors spend most of their time indoors, our focus is on strategies that prioritize the transformation of residential environments for indoor thermal comfort and air quality improvements. For each strategy, we develop specific scenarios related to building adaptations and test potential reductions on indoor overheating and pollutant exposures from outdoor sources (PM2.5), as well as on senior mortality through the CRAFT tool (Cities Rapid Assessment Framework for Transformation). We then pick the scenarios with highest impacts on mortality, aiming to formulate effective policy recommendations for Greater London. Preliminary results suggest that environmental policies related to the installation of shading could have the highest reduction in heat and pollution-related senior mortality, followed by moderate effects due to building insulation retrofits and the greening of roofs. With an increasing ageing population in the UK and beyond, our work highlights the need for city-level policies to address building modifications, considering the importance of indoor spaces for older adults

    Home Energy Efficiency and Subjective Health in Greater London

    Get PDF
    The UK has introduced legislation that requires net-zero greenhouse gas emissions to be achieved by 2050. Improving the energy efficiency of homes is a key objective to help reach this target, and the UK government's Clean Growth Strategy aims to get many homes up to an Energy Performance Certificate (EPC) Band of C by 2035. The relationship between home energy-efficiency and occupant health and wellbeing remains an area of ongoing research. This paper explores the nexus between home energy efficiency, energy consumption and self-reported health-an indicator of the general health and wellbeing of the population. We focus on Greater London through secondary data analysis. Energy-efficiency ratings and air infiltration rates of dwellings, derived from EPCs, were aggregated and matched to local area self-reported health and energy consumption data obtained from the Greater London Authority's (GLA) Lower Layer Super Output Area (LSOA) Atlas database. Our regression model indicates that improving the energy efficiency (SAP) rating by 10 points for a typical home may reduce household gas consumption by around 7% (95% CIs: 2%, 14%). Beta regression finds a positive, but not statistically significant association between median SAP rating and the proportion of the population reporting 'good or very good' health when considering all Greater London LSOAs (z score = 0.60, p value = 0.55). A statistically significant positive association is observed however when repeating the analysis for the lowest income quartile LSOAs (z score = 2.03, p value = 0.04). This indicates that the least well-off may benefit most from home energy efficiency programs. A statistically significant positive association is also observed for the relationship between self-reported health and air infiltration rates (z score = 2.62, p value = 0.01). The findings support existing evidence for the predominantly naturally ventilated UK housing stock, suggesting that home energy efficiency measures provide a co-benefit for occupant health provided that adequate air exchange is maintained

    Characterising the Physiological Responses of Chinook Salmon (Oncorhynchus tshawytscha) Subjected to Heat and Oxygen Stress.

    Get PDF
    In New Zealand, during the hottest periods of the year, some salmon farms in the Marlborough Sounds reach water temperatures above the optimal range for Chinook salmon. High levels of mortality are recorded during these periods, emphasising the importance of understanding thermal stress in this species. In this study, the responses of Chinook salmon (Oncorhynchus tshawytscha) to chronic, long-term changes in temperature and dissolved oxygen were investigated. This is a unique investigation due to the duration of the stress events the fish were exposed to. Health and haematological parameters were analysed alongside gene expression results to determine the effects of thermal stress on Chinook salmon. Six copies of heat shock protein 90 (HSP90) were discovered and characterised: HSP90AA1.1a, HSP90AA1.2a, HSP90AA1.1b, HSP90AA1.2b, HSP90AB1a and HSP90AB1b, as well as two copies of SOD1, named SOD1a and SOD1b. The amino acid sequences contained features similar to those found in other vertebrate HSP90 and SOD1 sequences, and the phylogenetic tree and synteny analysis provided conclusive evidence of their relationship to other vertebrate HSP90 and SOD1 genes. Primers were designed for qPCR to enable the expression of all copies of HSP90 and SOD1 to be analysed. The expression studies showed that HSP90 and SOD1 were downregulated in the liver and spleen in response to longer term exposure to high temperatures and lower dissolved oxygen. HSP90 was also downregulated in the gill; however, the results for SOD1 expression in the gill were not conclusive. This study provides important insights into the physiological and genetic responses of Chinook salmon to temperature and oxygen stress, which are critical for developing sustainable fish aquaculture in an era of changing global climates

    A portable diagnostic device for cardiac magnetic field mapping

    Get PDF
    In this paper we present a portable magnetocardiography device. The focus of this development was delivering a rapid assessment of chest pain in an emergency department. The aim was therefore to produce an inexpensive device that could be rapidly deployed in a noisy unshielded ward environment. We found that induction coil magnetometers with a coil design optimized for magnetic field mapping possess sufficient sensitivity (104fT /√ Hz noise floor at 10Hz) and response (813fT /µV at 10Hz) for cycle averaged magnetocardiography and are able to measure depolarisation signals in an unshielded environment. We were unable to observe repolarisation signals to a reasonable fidelity. We present the design of the induction coil sensor array and signal processing routine along with data demonstrating performance in a hospital environment

    A participatory process for modelling green infrastructure implementation in London

    Get PDF
    Cities face the interlinked challenges of transforming environmental quality, sustainability, population health and health equity. There is increasing interest in green infrastructure in connection with these challenges. In order to go beyond an understanding of the effects of green infrastructure and develop an understanding of how policymakers should think about it, we need to capture potential interactions and be aware of possible unintended consequences. In our research, we applied a systems-thinking approach: integrating participatory engagements, qualitative system dynamics modelling, and an assessment framework in order to address the challenge. This allowed us to see multiple dynamics between the prioritisation of policymakers, different types of green infrastructure, and environmental and health outcomes. It also made us ask different and more integrated questions, and suggested a methodology for addressing the challenge of transforming cities
    corecore