2,374 research outputs found

    Numerical simulation of rivulet evolution on a horizontal cable subject to an external aerodynamic field

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    On wet and windy days, the inclined cables of cable-stayed bridges may experience a large amplitude oscillation known as rain-wind-induced vibration (RWIV). It has previously been shown by in situ and wind-tunnel studies that the formation of rain-water accumulations or ‘rivulets’ at approximately the separation points of the external aerodynamic flow field and the resulting effect that these rivulets have on this field may be one of the primary mechanisms for RWIV. A numerical method has been developed to undertake simulations of certain aspects of RWIV, in particular, rivulet formation and evolution. Specifically a two-dimensional model for the evolution of a thin film of water on the outer surface of a horizontal circular cylinder subject to the pressure and shear forces that result from the external flow field is presented. Numerical simulations of the resulting evolution equation using a bespoke pseudo-spectral solver capture the formation of two-dimensional rivulets, the geometry, location and growth rate of which are all in good agreement with previous studies. Examinations of how the distribution and magnitude of aerodynamic loading and the Reynolds number influence the rivulet temporal evolution are undertaken, the results of which indicate that while all three affect the temporal evolution, the distribution of the loading has the greatest effect

    New developments in rain–wind-induced vibrations of cables

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    On wet and windy days, the inclined cables of cable stayed bridges can experience large amplitude, potentially damaging oscillations known as rain-wind-induced vibration (RWIV). RWIV is believed to be the result of a complicated non-linear interaction between rivulets of rain water that run down the cables and the wind loading on the cables from the unsteady aerodynamics; however, despite a considerable international research effort, the underlying physical mechanism that governs this oscillation is still not satisfactorily understood. An international workshop on RWIV was held in April 2008, hosted at the University of Strathclyde. The main outcomes of this workshop are summarised in the paper. A numerical method to investigate aspects of the RWIV phenomenon has recently been developed by the authors, which couples an unsteady aerodynamic solver to a thin-film model based on lubrication theory for the flow of the rain water to ascertain the motion of the rivulets owing to the unsteady aerodynamic field. This novel numerical technique, which is still in the relatively early stages of development, has already provided useful information on the coupling between the external aerodynamic flow and the rivulet, and a summary of some of the key results to date is presented

    MIRACLE Progress in Monolingual Information Retrieval at Ad-Hoc CLEF 2007

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    This paper presents the 2007 MIRACLE’s team approach to the Ad-Hoc Information Retrieval track. The main work carried out for this campaign has been around monolingual experiments, in the standard and in the robust tracks. The most important contributions have been the general introduction of automatic named-entities extraction and the use of Wikipedia resources. For the2007 campaign, runs were submitted for the following languages and tracks: a) Monolingual: Bulgarian, Hungarian, and Czech. b) Robust monolingual: French, English and Portuguese

    Teaching business plan negotiation : how to foster entrepreneurship with engineering students

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    Though negotiations are an imperative aspect of business dealing, most university students do not receive the necessary training to acquire adequate skills in this area. Role plays are a suggested teaching tool to enhance the learning experience by creating an environment that more closely resembles life situations. The business plan negotiation uses this to assist students in gaining experience in the area of business negotiations. The negotiation is involves students playing as a startup IT company, trying to negotiate funding from venture capitalists. The negotiation adds their experience with the observations of other students and experienced negotiators

    Seeking counselling for mood disorders in a cardiac centre: a pilot survey of patients’ views

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    Research suggests a relationship exists between patients with ischemic heart trauma, and mood disorders and that there is therefore a need for psychosocial assessment and, where necessary, treatment for these disorders among heart attack patients [1]. Yet, assessment and treatment for mood disorders is rarely a priority in the cardiologist's office. Thus, counselling therapies for cardiac patients with co-occurring mood disorder are rarely considered or addressed in the cardiologist's office. This study sought to investigate whether cardiac patients would use counselling services if offered in the cardiologist's office. Results suggested mixed sentiments regarding counselling treatment for mood disorders in the cardiologist's office, particularly with regard to sex-differences. Discussion focuses on these sex-differences and the role aspects of ‘gender' and ‘masculinity' may play in accounting for such differences. The paper also discusses the significance of age differences. Implications for interdisciplinary collaboration are presented

    Variation in the responses of wild species of duck, gull, and wader to inoculation with a wild-bird-origin H6N2 low pathogenicity avian influenza virus

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    There is poor understanding of host responses to avian influenza virus (AIV) infection in wild birds, with most experimental studies using captive-bred birds and highly pathogenic AIVs that have an early endpoint. The objective of this study was to experimentally assess antibody responses and patterns of viral excretion in wild birds challenged with a low pathogenicity AIV. Ruddy turnstones (Arenaria interpres), silver gulls (Chroicocephalus novaehollandiae), and wandering whistling ducks (Dendrocygna arcuata) were challenged with a H6N2 virus, and blood, cloacal, and oropharyngeal (OP) swabs were analyzed from each bird over 28 days, with serology conducted on the ducks for a further 7 mo. Nineteen of 22 birds showed evidence of infection, with respiratory infection prevalent in the turnstones and gulls as mostly low titer viral excretion to 4 days postinoculation (DPI) with gastrointestinal replication detected in only one turnstone. In AIV naive ducks, there was gastrointestinal tropism with moderately high titer viral excretion via the cloaca to 6 DPI and low-grade OP viral excretion to 4 DPI. The hemagglutination inhibition antibody response was poor in the ducks, declining from 19 to 56 DPI, with higher titer responses in the gulls and turnstones. All infected birds responded with elevated nucleoprotein antibodies (in competitive enzyme-linked immunosorbent assay) by 7-10 DPI, and in the ducks these waned slowly after 42 DPI and were long-lived to at least 8 mo. The interspecies variability in response was consistent with a subtype that had adapted well in ducks, while the response of the turnstones may have been influenced by preexisting immunity to AIV. These findings provide insight into AIV infection dynamics in wild birds and highlight the need for further research
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