125 research outputs found

    Measurement and analysis of fatigue crack deformation at the micro-scale

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    This paper introduces the use of digital image correlation for the measurement of surface displacements in the neighbourhood of a crack tip, both at the macro- and micro- scale. Various methods of interpreting the measured data and producing a crack driving force are then discussed, including the use of the full CJP model. A reduced set of parameters are then proposed, corresponding to the three principal interaction forces between the plastic enclave and the surrounding elastic material. Our own results, and those of Vasco Olmo, previously reported in the literature are then reanalysed using this new framework, and excellent agreement between two independent experiments is obtained. Implications for the analysis of further data sets are then discussed

    Measurement and analysis of fatigue crack deformation on the macro- and micro-scale

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    The paper describes an experiment which performs in-situ loading of a small compact tensionspecimen in a scanning electron microscope. Images are collected throughout a number of successive loadincgcycles. These are then analysed using digital image correlation (DIC) in order to produce crack flankdisplacements as a function of load. This data is then compared with a simple elastic approach, and it is concludedthat elastic-plastic analysis is required in order to accurately capture the displacements close to the crack tip. Asimple approach due to Pommier and Hamam is therefore employed. This gives a better representation of thedata, but predicts a variation of crack tip displacement, ?, which is difficult to explain from a physical perspective.The need for a more sophisticated analysis of the data is therefore highlighted

    Biosecurity risks posed by a large sea-going passenger vessel: Challenges of terrestrial arthropod species detection and eradication

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    Large sea-going passenger vessels can pose a high biosecurity risk. The risk posed by marine species is well documented, but rarely the risk posed by terrestrial arthropods. We conducted the longest running, most extensive monitoring program of terrestrial arthropods undertaken on board a passenger vessel. Surveillance was conducted over a 19-month period on a large passenger (cruise) vessel that originated in the Baltic Sea (Estonia). The vessel was used as an accommodation facility to house workers at Barrow Island (Australia) for 15 months, during which 73,061 terrestrial arthropods (222 species - four non-indigenous (NIS) to Australia) were collected and identified on board. Detection of Tribolium destructor Uytt., a high-risk NIS to Australia, triggered an eradication effort on the vessel. This effort totalled more than 13,700 human hours and included strict biosecurity protocols to ensure that this and other non-indigenous species (NIS) were not spread from the vessel to Barrow Island or mainland Australia. Our data demonstrate that despite the difficulties of biosecurity on large vessels, stringent protocols can stop NIS spreading from vessels, even where vessel-wide eradication is not possible. We highlight the difficulties associated with detecting and eradicating NIS on large vessels and provide the first detailed list of species that inhabit a vessel of this kind

    Entanglement, quantum phase transition and scaling in XXZ chain

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    Motivated by recent development in quantum entanglement, we study relations among concurrence CC, SUq_q(2) algebra, quantum phase transition and correlation length at the zero temperature for the XXZ chain. We find that at the SU(2) point, the ground state possess the maximum concurrence. When the anisotropic parameter Δ\Delta is deformed, however, its value decreases. Its dependence on Δ\Delta scales as C=C0−C1(Δ−1)2C=C_0-C_1(\Delta-1)^2 in the XY metallic phase and near the critical point (i.e. 1<Δ<1.31<\Delta<1.3) of the Ising-like insulating phase. We also study the dependence of CC on the correlation length ξ\xi, and show that it satisfies C=C0−1/2ξC=C_0-1/2\xi near the critical point. For different size of the system, we show that there exists a universal scaling function of CC with respect to the correlation length ξ\xi.Comment: 4 pages, 3 figures. to appear in Phys. Rev.

    Multiethnic meta-analysis identifies ancestry-specific and cross-ancestry loci for pulmonary function

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    Nearly 100 loci have been identified for pulmonary function, almost exclusively in studies of European ancestry populations. We extend previous research by meta-analyzing genome-wide association studies of 1000 Genomes imputed variants in relation to pulmonary function in a multiethnic population of 90,715 individuals of European (N = 60,552), African (N = 8429), Asian (N = 9959), and Hispanic/Latino (N = 11,775) ethnicities. We identify over 50 additional loci at genome-wide significance in ancestry-specific or multiethnic meta-analyses. Using recent fine-mapping methods incorporating functional annotation, gene expression, and differences in linkage disequilibrium between ethnicities, we further shed light on potential causal variants and genes at known and newly identified loci. Several of the novel genes encode proteins with predicted or established drug targets, including KCNK2 and CDK12. Our study highlights the utility of multiethnic and integrative genomics approaches to extend existing knowledge of the genetics of l

    Customer emotions in service failure and recovery encounters

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    Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employee–customer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences

    Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study

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    A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4

    Dynamic assessment precursors: Soviet ideology, and Vygotsky

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    Were New Labour’s cultural policies neo-liberal?

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    This article assesses the cultural policies of ‘New Labour’, the UK Labour government of 1997–2010. It takes neo-liberalism as its starting point, asking to what extent Labour’s cultural policies can be validly and usefully characterised as neo-liberal. It explores this issue across three dimensions: corporate sponsorship and cuts in public subsidy; the running of public sector cultural institutions as though they were private businesses; and a shift in prevailing rationales for cultural policy, away from cultural justifications, and towards economic and social goals. Neo-liberalism is shown to be a significant but rather crude tool for evaluating and explaining New Labour’s cultural policies. At worse, it falsely implies that New Labour did not differ from Conservative approaches to cultural policy, downplays the effect of sociocultural factors on policy-making, and fails to differentiate varying periods and directions of policy. It does, however, usefully draw attention to the public policy environment in which Labour operated, in particular the damaging effects of focusing, to an excessive degree, on economic conceptions of the good in a way that does not recognise the limitations of markets as a way of organising production, circulation and consumption
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