1,975 research outputs found

    Study of electrocatalysis for direct alcohol fuel cells (DAFC)

    Get PDF
    Under this work an automated 5 inch single-cell PEM fuel cell was retrofitted with a computer controlled syringe pump and operated as a DAFC. Catalyst synthesis procedures were developed in-house for DAFC catalysts preparations. Six catalysts, PtSn/C, Pt2Sn/C, Pt 2SnRu/C, PtSnRu0.5/C, PtSn0.5Ru/C and Pd/C were prepared, and their mass composition estimated through mass balance calculations. A series of experiments for VI performance data and power output were performed in the DAFC at different temperatures (75°C, 80°C, 85°C) and 1M ethanol flow rates (0.32ml/min, 1ml/min, 2ml/min) with a fixed catalyst loading of 1mg/cm2 platinum. It was found that the binary platinum-tin catalysts produced about 18% more power than the ternary platinum-tin-ruthenium catalysts in the DAFC

    Guidance on the use of synthetic fibre ropes for marine energy devices

    Get PDF
    Deliverable 3.5.2 from the MERiFIC Project A report prepared as part of the MERiFIC Project "Marine Energy in Far Peripheral and Island Communities"his report is a deliverable of MERiFIC Work Package 3: ‘Dynamic Behaviour of Marine Energy Devices’ involving the collaboration of IFREMER (Institut français de recherche pour l'exploitation de la mer) in France and the University of Exeter in the United Kingdom. Although synthetic ropes have been used for the station-keeping of offshore structures for the past two decades predominantly by the oil, gas and shipping industries, there is considerable interest in their utilisation for the station-keeping of marine renewable energy (MRE) devices. Differences in application between typically small, highly responsive devices (e.g. Wave Energy Converters or WECs) and large slow-moving platforms necessitate a unique approach to mooring system design and dedicated mooring component test programs, both guided by relevant certification standards. It is the intention of this report to provide an introduction to synthetic mooring ropes in the context of previous usage in the offshore industry and also to highlight factors which should be considered for their use in MRE mooring systems. The document begins by setting the scene to give background on the fundamental differences between previous applications of synthetic mooring ropes and MRE devices. In Section 2 a brief overview of commercially available ropes is then given. The distinct properties of synthetic materials and rope constructions are summarised with emphasis placed on issues which are likely to be relevant for MRE devices. In the absence of specific advice for this emerging industry, conventional approaches to applying safety factors to synthetic ropes are then introduced. Section 3 highlights in-service considerations relevant for the different lifecycle stages of ropes, from installation and operational procedures (such as maintenance and inspection) to decommissioning. Specific modelling approaches for synthetic ropes are then summarised in Section 4, followed by a summary in Section 5. This document is not intended to be an exhaustive account of all aspects of synthetic mooring ropes and in light of this further references are provided for the interested reader.MERiFIC was selected under the European Cross-Border Cooperation Programme INTERREG IV A France (Channel) – England, co-funded by the ERD

    Radio Galaxy Zoo: Cosmological Alignment of Radio Sources

    Get PDF
    We study the mutual alignment of radio sources within two surveys, FIRST and TGSS. This is done by producing two position angle catalogues containing the preferential directions of respectively 3005930\,059 and 1167411\,674 extended sources distributed over more than 70007\,000 and 1700017\,000 square degrees. The identification of the sources in the FIRST sample was performed in advance by volunteers of the Radio Galaxy Zoo project, while for the TGSS sample it is the result of an automated process presented here. After taking into account systematic effects, marginal evidence of a local alignment on scales smaller than 2.5deg2.5\deg is found in the FIRST sample. The probability of this happening by chance is found to be less than 22 per cent. Further study suggests that on scales up to 1.5deg1.5\deg the alignment is maximal. For one third of the sources, the Radio Galaxy Zoo volunteers identified an optical counterpart. Assuming a flat Λ\LambdaCDM cosmology with Ωm=0.31,ΩΛ=0.69\Omega_m = 0.31, \Omega_\Lambda = 0.69, we convert the maximum angular scale on which alignment is seen into a physical scale in the range [19,38][19, 38] Mpc h701h_{70}^{-1}. This result supports recent evidence reported by Taylor and Jagannathan of radio jet alignment in the 1.41.4 deg2^2 ELAIS N1 field observed with the Giant Metrewave Radio Telescope. The TGSS sample is found to be too sparsely populated to manifest a similar signal

    Radio galaxies and their magnetic fields out to z <= 3

    Full text link
    We present polarisation properties at 1.41.4\,GHz of two separate extragalactic source populations: passive quiescent galaxies and luminous quasar-like galaxies. We use data from the {\it Wide-Field Infrared Survey Explorer} data to determine the host galaxy population of the polarised extragalactic radio sources. The quiescent galaxies have higher percentage polarisation, smaller radio linear size, and 1.41.4\,GHz luminosity of 6×1021<L1.4<7×10256\times10^{21}<L_{\rm 1.4}<7\times10^{25}\,W Hz1^{-1}, while the quasar-like galaxies have smaller percentage polarisation, larger radio linear size at radio wavelengths, and a 1.41.4\,GHz luminosity of 9×1023<L1.4<7×10289\times10^{23}<L_{\rm 1.4}<7\times10^{28}\,W Hz1^{-1}, suggesting that the environment of the quasar-like galaxies is responsible for the lower percentage polarisation. Our results confirm previous studies that found an inverse correlation between percentage polarisation and total flux density at 1.41.4\,GHz. We suggest that the population change between the polarised extragalactic radio sources is the origin of this inverse correlation and suggest a cosmic evolution of the space density of quiescent galaxies. Finally, we find that the extragalactic contributions to the rotation measures (RMs) of the nearby passive galaxies and the distant quasar-like galaxies are different. After accounting for the RM contributions by cosmological large-scale structure and intervening Mg\,{II} absorbers we show that the distribution of intrinsic RMs of the distant quasar-like sources is at most four times as wide as the RM distribution of the nearby quiescent galaxies, if the distribution of intrinsic RMs of the WISE-Star sources itself is at least several rad m2^{-2} wide.Comment: 12 pages, 8 figures, accepted for publication into MNRA

    Time's up. Descriptive epidemiology of multi-morbidity and time spent on health related activity by older Australians: a time use survey

    Get PDF
    Most Western health systems remain single illness orientated despite the growing prevalence of multi-morbidity. Identifying how much time people with multiple chronic conditions spend managing their health will help policy makers and health service providers make decisions about areas of patient need for support. This article presents findings from an Australian study concerning the time spent on health related activity by older adults (aged 50 years and over), most of whom had multiple chronic conditions. A recall questionnaire was developed, piloted, and adjusted. Sampling was undertaken through three bodies; the Lung Foundation Australia (COPD sub-sample), National Diabetes Services Scheme (Diabetes sub-sample) and National Seniors Australia (Seniors sub-sample). Questionnaires were mailed out during 2011 to 10,600 older adults living in Australia. 2540 survey responses were received and analysed. Descriptive analyses were completed to obtain median values for the hours spent on each activity per month. The mean number of chronic conditions was 3.7 in the COPD sub-sample, 3.4 in the Diabetes sub-sample and 2.0 in the NSA sub-sample. The study identified a clear trend of increased time use associated with increased number of chronic conditions. Median monthly time use was 5-16 hours per month overall for our three sub-samples. For respondents in the top decile with five or more chronic conditions the median time use was equivalent to two to three hours per day, and if exercise is included in the calculations, respondents spent from between five and eight hours per day: an amount similar to full-time work. Multi-morbidity imposes considerable time burdens on patients. Ageing is associated with increasing rates of multi-morbidity. Many older adults are facing high demands on their time to manage their health in the face of decreasing energy and mobility. Their time use must be considered in health service delivery and health system reform.This work was funded by the National Health and Medical Research Council ID (402793, 2006)

    The WiFeS S7 AGN survey: Current status and recent results on NGC 6300

    Full text link
    The Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) is a targeted survey probing the narrow-line regions (NLRs) of a representative sample of ~140 nearby (z<0.02) Seyfert galaxies by means of optical integral field spectroscopy. The survey is based on a homogeneous data set observed using the Wide Field Spectrograph WiFeS. The data provide a 25x38 arcsec2^2 field-of-view around the galaxy centre at typically ~1.5 arcsec spatial resolution and cover a wavelength range between ~3400 - 7100 A˚\AA at spectral resolutions of ~100 km s1^{-1} and ~50 km s1^{-1} in the blue and red parts, respectively. The survey is primarily designed to study gas excitation and star formation around AGN, with a special focus on the shape of the AGN ionising continuum, the interaction between radio jets and the NLR gas, and the nature of nuclear LINER emission. We provide an overview of the current status of S7-based results and present new results for NGC 6300.Comment: 5 pages, 1 figure, Refereed Proceeding of the "The Universe of Digital Sky Surveys" conference held at the INAF - Observatory of Capodimonte, Naples, on 25th-28th november 2014, to be published on Astrophysics and Space Science Proceedings, edited by Longo, Napolitano, Marconi, Paolillo, Iodic

    Hypernetwork functional image representation

    Full text link
    Motivated by the human way of memorizing images we introduce their functional representation, where an image is represented by a neural network. For this purpose, we construct a hypernetwork which takes an image and returns weights to the target network, which maps point from the plane (representing positions of the pixel) into its corresponding color in the image. Since the obtained representation is continuous, one can easily inspect the image at various resolutions and perform on it arbitrary continuous operations. Moreover, by inspecting interpolations we show that such representation has some properties characteristic to generative models. To evaluate the proposed mechanism experimentally, we apply it to image super-resolution problem. Despite using a single model for various scaling factors, we obtained results comparable to existing super-resolution methods

    An evaluation of the construct of body image

    Full text link
    Provides information on two studies which were designed to evaluate the efficacy of a multidimensional model of body image that incorporated the dimensions of perception, effect, cognition and behavior. Methodology used in the study; Results and general discussion
    corecore