4,747 research outputs found

    Effect of homogenisation conditions on recrystallisation in the Al-Mg-Mn alloy AA5454

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    The purpose of the present work is to understand the microstructure development and, particularly, to control the progress of recrystallisation in hot strip in the Al-Mg-Mn alloy AA 5454, which is typically used for the manufacture of structural automotive components. The chemical composition, together with the thermomechanical processing history of this material, has a strong influence on the microstructure of the product and the resulting properties as it is supplied to the customer. Electrical conductivity measurements, thermal analysis and electron microscopy have been carried out to characterise the evolution of precipitation state at various stages in the processing route. The conditions of the homogenisation heat treatment have been varied, and the effect on subsequent recrystallisation after hot rolling has been evaluated in both the as cast and rough rolled condition by optical microscopy techniques. Results indicate that the conditions of homogenisation heat treatment and roughing rolling are critical for the generation of a suitable recrystallised microstructure in AA 5454 hot strip. A new two stage homogenisation practice has been developed to expedite post-rolling recrystallisation in this alloy

    Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

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    Strong 10 micrometer line emission from (c-12)(o-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features

    Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

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    Strong 10 micrometer line emission from (C-12)(O-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features

    Potential Biological Control Agents for \u3cem\u3eNassella neesiana\u3c/em\u3e (Poaceae) Invading Australian Native Grasslands

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    The introduction and proliferation of exotic stipoid grasses over the past 100 years seriously threatens agricultural productivity and the integrity of Australia\u27s indigenous flora and fauna, particularly its grasslands (McLaren et al., 1998). The full effect on biodiversity by the spread of these grasses is unknown but likely to be major (Hocking, 1998). Conventional control techniques have not stopped the invasion adequately, so it is a priority to find control options to achieve an effective management strategy. A biological control project against Nassella trichotoma and N. neesiana was initiated in 1999 in Argentina. We report on the most recent findings on two pathogens, Puccinia nassellae and Uromyces cf pencanus, selected on the basis of previous results (Anderson et al., 2004), as potential biological control agents against N. neesiana, a South American species that can dominate both pasture and native grasslands in Australia

    Open Access in UCL: a new paradigm for London's Global University in research support

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    Open Access provides an opportunity for researchers to disseminate their research globally, but it comes with challenges. This article looks at the various ways in which UCL (University College London) has addressed those challenges, by investing in Open Access activities at the university

    Renal allograft recipients with high susceptibility to cutaneous malignancy have an increased prevalence of human papillomavirus DNA in skin tumours and a greater risk of anogenital malignancy.

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    Renal allograft recipients (RARs) have a well-documented increased incidence of viral warts and cutaneous neoplasia, particularly those with long graft life and high sun exposure. A clinicopathological survey of 69 RARs in south-east Scotland, with follow-up periods of up to 28 years after transplantation, revealed marked variation in patient susceptibility to cutaneous malignancy with concomitant variation in HPV prevalence. Skin cancers were found in 34 patients. Eight patients showed high susceptibility [defined as more than four intraepidermal carcinomas (IECs) or invasive squamous cell carcinomas (SCCs)] 42 had intermediate susceptibility (1-3 IECs or SCCs, or >3 keratoses) and 18 had low susceptibility (< or = 3 keratoses and no cancers). SCCs, IECs and keratoses from the high-susceptibility group were found to have greater prevalences of human papillomavirus (HPV) DNA (56%, 45% and 50% respectively), than SCCs (0%) and IECs (33%) from intermediate-susceptibility RARs and keratoses (36%) from the combined intermediate- and low-susceptibility groups and compared with a group of immunocompetent controls (27%, 20% and 15% respectively). No differences in p53 protein accumulation, determined immunohistochemically, were observed in tumours from the three groups. Categorization of RARs by susceptibility to cutaneous malignancy provides clinically useful information, as significantly more high-susceptibility patients (38%) developed aggressive, potentially lethal anogenital or cutaneous squamous cell cancers than did patients in the intermediate group (5%, P=0.005) or the low-susceptibility group (0%)
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