12,676 research outputs found

    The UARS and open data concept and analysis study

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    Alternative concepts for a common design for the UARS and OPEN Central Data Handling Facility (CDHF) are offered. Costs for alternative implementations of the UARS designs are presented, showing that the system design does not restrict the implementation to a single manufacturer. Processing demands on the alternative UARS CDHF implementations are then discussed. With this information at hand together with estimates for OPEN processing demands, it is shown that any shortfall in system capability for OPEN support can be remedied by either component upgrades or array processing attachments rather than a system redesign. In addition to a common system design, it is shown that there is significant potential for common software design, especially in the areas of data management software and non-user-unique production software. Archiving the CDHF data are discussed. Following that, cost examples for several modes of communications between the CDHF and Remote User Facilities are presented. Technology application is discussed

    Transport and Older People: Integrating Transport Planning Tools with User Needs

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    This study was funded through a pump-priming grant from the Strategic Promotion of Ageing Research Capacity (SPARC) programme. The purpose of the project was to bring together transport and public health research in order to demonstrate how the involvement of older people can help improve tools for transport planning. The study was unique in that it brought together public health and transport planning and engineering with older people to consider how services can be more responsive to older people’s transport needs. The project had five research objectives: 1. To investigate how accessibility problems impact on older people’s independence 2. To determine the extent to which currently available data sources and modelling tools reflect older people’s stated accessibility needs 3. To understand how the gap between expected and perceived accessibility problems varies across different categories of older people 4. To pilot techniques that could be applied to provide a more robust measure of accessibility for older people. 5. To build new research capacity across disciplines to develop a national focus on the interactions between ageing and transport planning. The methods were determined on the basis of ‘appropriate tools with maximum output’. Focus group interviews were selected as a useful tool for reaching a large number of older people within a limited time span, for providing an arena for discussion and debate about a topical subject and for generating ideas for improving transport planning. Following the interviews accompanied walks were undertaken with older people in a range of road environments and traffic situations. The purpose of these walks was to observe and explore the way older people interact with their environment. Data from the focus group interviews and the observations were compared with the outputs from an accessibility planning tool used by local authorities to plan accessible and acceptable transport routes (Accession™). The purpose of this exercise was to investigate whether or not such tools are able to take into account the varying needs of older people. The study was undertaken over eight months. Eighty one older people living in the Leeds district took part in the focus groups. They covered a broad range of mobility levels and used a variety of transport types, as such a reasonably rounded perspective on the issues concerned was offered. In addition six walks were undertaken with older people in their community

    Promoting and maintaining health of people with sight loss: A scoping study

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    This study was undertaken in response to a request by the Thomas Pocklington Trust to identify and explore the following issues: • The needs and concerns regarding immediate risks to health and safety related to sight loss; • Additional risks arising from sight loss for those who are also managing a long term disease; • The difficulties in maintaining and promoting health; • Whether or not health promotion activities and policies sufficiently address perceived needs. Findings pertaining to these objectives have been generated from data collected in Leeds, UK, a city where innovative programming for sight loss has either been planned or is being incorporated into health planning and a review of the literature. Findings related to the last two issues indicate that gaps exist in service provision for maintaining health and emphasise the need for more explicitly targeted health promotion initiatives that could address current weaknesses. - A review of the literature; - Focus group discussions with a range of people who had experienced sight loss; - Interviews with professional practitioners engaged in service provision to this population; - An expert hearing with four professional practitioners, one of whom had sight loss, and two service users with sight loss. Most participants were from the West Yorkshire region and the services described in the study are largely located in Leeds. Evidence from the literature review suggests that people with visual impairment have increased risk of accidents within the home and that ensuing consequences include injuries incurred and decreased confidence. Rates of depression among people who are blind or partially sighted are far higher than in the wider population and the likelihood of depression increases with age, although psycho-social interventions and technological assistance can be successfully implemented to improve quality of life. Sight loss together with other long term health conditions exacerbates the impact of other health conditions and has particularly severe impact on the wellbeing of older people insofar as it may affect their mobility, which in turn increases their risk of falls and depression. The nature and level of support available to people is variable but it is clear that access both to the right information at the right time and to appropriate services is a critical issue. Focus group discussions, interviews and the expert hearing corroborated and extended the themes noted in the literature and discuss the differential impact of different risks to health and the difficulties of coping with these at different times in a person’s life. A simple typology was defined using two dimensions of experience (‘stage of life’ and ‘early/late onset of sight loss’) as a means of organizing findings and providing a means of making further distinctions in interpreting the data. Potentially, this scheme can allow health promotion initiatives to be targeted more effectively to stages at which people with sight loss are more likely to encounter specific difficulties in managing and maintaining their health. There was a clear consensus throughout the study that interventions to meet the needs of people with sight loss must be tailored to meet the specific needs of individuals: people with sight loss are not a homogeneous group and the way in which each person experiences the challenges of sight loss and of managing their health will inevitably vary from person to person. Recommendations generated by this study include: • The scope for more pro-active services and need for closer collaboration between service providers; • The need for provision and promotion of targeted information; • The need for greater awareness of the needs of people with visual impairments among generic service providers; and • Further research that explores the usefulness of the typology with a larger sample more representative of population demographics such as BME communities that are more likely to slip through the cracks of service provision

    Forward acoustic performance of a shock-swallowing high-tip-speed fan (QF-13)

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    Forward noise and overall aerodynamic performance data are presented for a high-tip-speed fan having rotor blade airfoils designed to alter the conventional leading-edge bow shocks to weak, oblique shocks which are swallowed within the interblade channels. It was anticipated that the swallowed shocks would minimize the generation of multiple-pure-tone noise. In the speed range where the shocks presumably were swallowed, the multiple-tone noise was lowered only about 3 decibels. Comparison with several high-speed fans on a thrust-corrected basis indicates that the present fan was the quietest in total forward noise at low speeds but offered no advantage at high speeds

    Acoustic evaluation of a novel swept-rotor fan

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    Inlet noise and aerodynamic performance are presented for a high tip speed fan designed with rotor blade leading edge sweep that gives a subsonic component of inlet Mach number normal to the edge at all radii. The intent of the design was to minimize the generation of rotor leading edge shock waves thereby minimizing multiple pure tone noise. Sound power level and spectral comparisons are made with several high-speed fans of conventional design. Results show multiple pure tone noise at levels below those of some of the other fans and this noise was initiated at a higher tip speed. Aerodynamic performance of the fan did not meet design goals for this first build which applied conventional design procedures to the swept fan geometry

    Fan noise reduction achieved by removing tip flow irregularities behind the rotor - forward arc test configurations

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    The noise source caused by the interaction of the rotor tip flow irregularities (vortices and velocity defects) with the downstream stator vanes was studied. Fan flow was removed behind a 0.508 meter (20 in.) diameter model turbofan through an outer wall slot between the rotor and stator. Noise measurements were made with far-field microphones positioned in an arc about the fan inlet and with a pressure transducer in the duct behind the stator. Little tone noise reduction was observed in the forward arc during flow removal; possibly because the rotor-stator interaction noise did not propagate upstream through the rotor. Noise reductions were maded in the duct behind the stator and the largest decrease occurred with the first increment of flow removal. This result indicates that the rotor tip flow irregularity-stator interaction is as important a noise producing mechanism as the normally considered rotor wake-stator interaction

    Reduction of fan noise in an anechoic chamber by reducing chamber wall induced inlet flow disturbances

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    The difference between the flight and ground static noise of turbofan engines presents a significant problem in engine noise testing. The additional noise for static testing has been attributed to inlet flow disturbances or turbulence interacting with the fan rotor. In an attempt to determine a possible source of inflow disturbances entering fans tested in the Lewis Research Center anechoic chamber, the inflow field was studied using potential flow analysis. These potential flow calculations indicated that there was substantial flow over the wall directly behind the fan inlet that could produce significant inflow disturbances. Fan noise tests were run with various extensions added to the fan inlet to move the inlet away from this backwall and thereby reduce the inlet flow disturbances. Significant noise reductions were observed with increased inlet length. Over 5 db reduction of the blade passage tone sound power level was observed between the shortest and longest inlets at 90% fan speed and the first overtone was reduced 9 db. High frequency broadband noise was also reduced

    Effectiveness of an inlet flow turbulence control device to simulate flight noise fan in an anechoic chamber

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    A hemispherical inlet flow control device was tested on a 50.8 cm. (20-inch) diameter fan stage in the NASA-Lewis anechoic chamber. The control device used honeycomb and wire mesh to reduce turbulence intensities entering the fan. Far field acoustic power level results show about a 5 db reduction in blade passing tone and about 10 dB reduction in multiple pure tone sound power at 90% design fan speed with the inlet device in place. Hot film cross probes were inserted in the inlet to obtain data for two components of the turbulence at 65 and 90% design fan speed. Without the flow control device, the axial intensities were below 1.0%, while the circumferential intensities were almost twice this value. The inflow control device significantly reduced the circumferential turbulence intensities and also reduced the axial length scale

    The tail of the Jurassic fish Leedsichthys problematicus (Osteichthyes: Actinopterygii) collected by Alfred Nicholson Leeds - an example of the importance of historical records in palaeontology

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    The specimen of the tail of <i>Leedsichthys problematicus</i>, now in The Natural History Museum, London, was one of the most spectacular fossil vertebrates from the Oxford Clay Formation of Peterborough, but as an isolated find it shares no bones in common with the holotype of the genus and species. However, a letter from Alfred Nicholson Leeds and related documents cast valuable new light on the excavation of the tail, indicating that it was discovered with cranial bones, gill-rakers, and two pectoral fins, thereby including elements that can potentially be compared with those of the holotype. The documents also clearly indicate that The Natural History Museum's specimen is not part of the same individual as any other numbered specimen of <i>Leedsichthys</i> as had been speculated on other occasions. The maximum size of the animal represented by The Natural History Museum's specimen was possibly around 9 metres, considerably less than previous estimates of up to 27.6 metres for <i>Leedsichthys</i>. Historical documentary evidence should therefore be rigorously checked both when studying historical specimens in science, and in preparing text for museum display labels

    Study of the volume and spin collapse in orthoferrite LuFeO_3 using LDA+U

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    Rare earth (R) orthoferrites RFeO_3 exhibit large volume transitions associated with a spin collapse. We present here ab initio calculations on LuFeO_3. We show that taking into account the strong correlation among the Fe-3d electrons is necessary. Indeed, with the LDA+U method in the Projector Augmented Wave (PAW), we are able to describe the isostructural phase transition at 50 GPa, as well as a volume discontinuity of 6.0% at the transition and the considerable reduction of the magnetic moment on the Fe ions. We further investigate the effect of the variation of U and J and find a linear dependence of the transition pressure on these parameters. We give an interpretation for the non-intuitive effect of J. This emphasizes the need for a correct determination of these parameters especially when the LDA+U is applied to systems (e.g in geophysical investigations) where the transition pressure is a priori unknown
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