1,293 research outputs found

    A Chemical Kinetics Approach to The Duration-of-Load Problem in Wood

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    The theory of absolute rates of chemical processes is presented as an appropriate conceptual framework for understanding the creep-rupture phenomena of duration of load (DOL) and rate of loading (ROL). The theory predicts the following experimentally observed phenomena:(1) The logarithm of the time to failure under constant deadload stress increases linearly as the stress level is decreased.(2) The rupture strength in a linear-ramp ROL experiment increases with the logarithm of the rate of stressing.Moreover, the equations derived to describe these phenomena contain the same parameters. These parameters are denned physical quantities that describe the creep characteristics of the material. It is possible to predict how long a material will support a constant deadload stress (DOL behavior) from measurements of apparent rupture strength as a function of the rate of stressing in a linear-ramp loading experiment (ROL behavior).Rupture of Douglas-fir in bending is selected as an example, and the experimental results from ROL-behavior experiments are used to predict DOL behavior. The theory adequately describes the experimentally observed results

    Heat stress: A major contributor to poor animal welfare associated with long-haul live export voyages

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    Recent investigations by the Australian Department of Agriculture, Fisheries and Forestry into high mortalities on live export voyages from Australia to the Middle East during the Northern hemisphere summer suggest that animal welfare may be compromised by heat stress. The live export industry has generated a computer model that aims to assess the risk of heat stress and to contain mortality levels on live export ships below certain arbitrary limits. Although the model must be complied with under Australian law, it is not currently available for independent scientific scrutiny, and there is concern that model and the mandated space allowances are inadequate. This review appraises the relevant literature on heat stress in sheep and cattle, including laboratory studies aimed at mimicking the ambient temperatures and humidity levels likely to be encountered on live export voyages. Animal welfare is likely to be very poor as a result of heat stress in some shipments

    A USB Interfaced Motion Capture Sensor, Using Tri-Axis Magnetic/Inertial Sensors For Use In Kinematic Studies

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    An unobtrusive tri-axis magnetic and gravitational field transducer for use in kinematic tracking is presented. Outlined is a novel approach for using such a sensor i.e. providing a Universal Serial Bus (USB) interface, allowing the direct utilization of the logical topology of the standard, making scalable deployment possible. Furthermore design considerations; construction and performance of the sensor are analysed and discussed in detail

    A USB Interfaced Motion Capture Sensor, Using Tri-Axis Magnetic/Inertial Sensors For Use In Kinematic Studies

    Get PDF
    An unobtrusive tri-axis magnetic and gravitational field transducer for use in kinematic tracking is presented. Outlined is a novel approach for using such a sensor i.e. providing a Universal Serial Bus (USB) interface, allowing the direct utilization of the logical topology of the standard, making scalable deployment possible. Furthermore design considerations; construction and performance of the sensor are analysed and discussed in detail

    Optoelectronic Reservoir Computing

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    Reservoir computing is a recently introduced, highly efficient bio-inspired approach for processing time dependent data. The basic scheme of reservoir computing consists of a non linear recurrent dynamical system coupled to a single input layer and a single output layer. Within these constraints many implementations are possible. Here we report an opto-electronic implementation of reservoir computing based on a recently proposed architecture consisting of a single non linear node and a delay line. Our implementation is sufficiently fast for real time information processing. We illustrate its performance on tasks of practical importance such as nonlinear channel equalization and speech recognition, and obtain results comparable to state of the art digital implementations.Comment: Contains main paper and two Supplementary Material

    Exploring Alternative Terrain in the Rehabilitation and Treatment of Offenders: Findings from a Prison-based Music Project

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    The arts in prison settings have provided an alternative or complimentary component to rehabilitation. Despite increased interest, studies capturing the voice of offenders participating in projects and the long-term impact are limited. Data from semistructured interviews with 18 men who had taken part in a music-based project while incarcerated, including one group of five participants who were tracked for 18 months with supplemented data from correctional staff and official documentation, is presented. Participants of the art-based projects comment on changes they believe to have derived from participating in the project, particularly relating to emotions, self-esteem, self-confidence, communication and social skills. An exoffender sample of participants reported that participation in art projects provide experiences that promote beneficial skills that have been useful for post prison life

    A statistical model for the intrinsically broad superconducting to normal transition in quasi-two-dimensional crystalline organic metals

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    Although quasi-two-dimensional organic superconductors such as κ\kappa-(BEDT-TTF)2_2Cu(NCS)2_2 seem to be very clean systems, with apparent quasiparticle mean-free paths of several thousand \AA, the superconducting transition is intrinsically broad (e.g 1\sim 1 K wide for Tc10T_c \approx 10 K). We propose that this is due to the extreme anisotropy of these materials, which greatly exacerbates the statistical effects of spatial variations in the potential experienced by the quasiparticles. Using a statistical model, we are able to account for the experimental observations. A parameter xˉ\bar{x}, which characterises the spatial potential variations, may be derived from Shubnikov-de Haas oscillation experiments. Using this value, we are able to predict a transition width which is in good agreement with that observed in MHz penetration-depth measurements on the same sample.Comment: 8 pages, 2 figures, submitted to J. Phys. Condens. Matte

    Popular attitudes to memory, the body, and social identity : the rise of external commemoration in Britain, Ireland, and New England

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    A comparative analysis of samples of external memorials from burial grounds in Britain, Ireland and New England reveals a widespread pattern of change in monument style and content, and exponential growth in the number of permanent memorials from the 18th century onwards. Although manifested in regionally distinctive styles on which most academic attention has so far been directed, the expansion reflects global changes in social relationships and concepts of memory and the body. An archaeological perspective reveals the importance of external memorials in articulating these changing attitudes in a world of increasing material consumption

    Competition between Charge Ordering and Superconductivity in Layered Organic Conductors α\alpha-(BEDT-TTF)2M_2MHg(SCN)4_4 (M = K, NH4_4)

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    While the optical properties of the superconducting salt α\alpha-(BEDT-TTF)2_2NH4_4Hg(SCN)4_4 remain metallic down to 2 K, in the non-superconducting K-analog a pseudogap develops at frequencies of about 200 cm1^{-1} for temperatures T < 200 K. Based on exact diagonalisation calculations on an extended Hubbard model at quarter-filling we argue that fluctuations associated with short range charge ordering are responsible for the observed low-frequency feature. The different ground states, including superconductivity, are a consequence of the proximity of these compounds to a quantum phase charge-ordering transition driven by the intermolecular Coulomb repulsion.Comment: 4 pages, 3 figure
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