11,383 research outputs found
Research study to develop methods for solving problems associated with space vehicles Monthly progress report /Final/
Trigonometric function algorithms for algebraic simplification in computer program
Acoustic and aerodynamic performance of a 1.83-meter (6-ft) diameter 1.25-pressure-ratio fan (QF-8)
A 1.25-pressure-ratio 1.83-meter (6-ft) tip diameter experimental fan stage with characteristics suitable for engine application on STOL aircraft was tested for acoustic and aerodynamic performance. The design incorporated proven features for low noise, including absence of inlet guide vanes, low rotor blade tip speed, low aerodynamic blade loading, and long axial spacing between the rotor and stator blade rows. The fan was operated with five exhaust nozzle areas. The stage noise levels generally increased with a decrease in nozzle area. Separation of the acoustic one-third octave results into broadband and pure-tone components showed the broadband noise to be greater than the corresponding pure-tone components. The sideline perceived noise was highest in the rear quadrants. The acoustic results of QF-8 were compared with those of two similar STOL application fans in the test series. The QF-8 had somewhat higher relative noise levels than those of the other two fans. The aerodynamic results of QF-8 and the other two fans were compared with corresponding results from 50.8-cm (20-in.) diam scale models of these fans and design values. Although the results for the full-scale and scale models of the other two fans were in reasonable agreement for each design, the full-scale fan QF-8 results showed poor performance compared with corresponding model results and design expectations. Facility effects of the full-scale fan QF-8 installation were considered in analyzing this discrepancy
Transport and Older People: Integrating Transport Planning Tools with User Needs
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
Low-frequency rear quadrant noise of a turbojet engine with exhaust duct muffling
A J-65 engine was run with a tuned sound-absorbing exhaust duct to study the internal and jet components of rear quadrant noise. Full muffler, hard wall duct, and regular production engine configurations were tested. The jet exhaust velocities were subsonic. The use of the exhaust muffler extended the relation between the jet noise and the eighth power of the jet velocity to lower velocities than for the hard wall duct
Estimating Sighting Proportions of American Alligator Nests during Helicopter Survey
Proportions of American alligator (Alligator mississippiensis) nests sighted
during aerial survey in Florida were estimated based upon multiple surveys by different
observers. We compared sighting proportions across habitats, nesting seasons, and observer
experience levels. The mean sighting proportion across all habitats and years was
0.736 (SE=0.024). Survey counts corrected by the mean sighting proportion reliably
predicted total nest counts (R2=0.933). Sighting proportions did not differ by habitat
type (P=0.668) or year P=0.328). Experienced observers detected a greater proportion
of nests (P<O.OOOl) than did either less experienced or inexperienced observers. Reliable
estimates of nest abundance can be derived from aerial counts of alligator nests
when corrected by the appropriate sighting proportion
Acoustic and aerodynamic performance of a 1.83 meter (6 foot) diameter 1.2 pressure ratio fan (QF-6)
A 1.2-pressure-ratio, 1.83-meter-(6-ft-) diameter experimental fan stage with characteristics suitable for use in STOL aircraft engines was tested for acoustic and aerodynamic performance. The design incorporated features for low noise, including absence of inlet guide vanes, low rotor-blade-tip speed, low aerodynamic blade loading, and long axial spacing between the rotor and stator rows. The stage was run with four nozzles of different area. The perceived noise along a 152.4 meter (500-ft) sideline was rear-quadrant dominated with a maximum design-point level of 103.9 PNdb. The acoustic 1/3-octave results were analytically separated into broadband and pure-tone components. It was found that the stage noise levels generally increase with a decrease in nozzle area, with this increase observed primarily in the broadband noise component. A stall condition was documented acoustically with a 90-percent-of-design-area nozzle
The Leeds Winter Warmth Campaign: Stakeholder Evaluation
The winter of 2012/13 was longer and colder than usual; whilst temperatures were average in December, it was colder than usual from January through to May. March was the coldest it has been for 50 years (Met Office, 2013). This evaluation focuses on the organisations funded by the Winter Warmth campaign to deliver services to Leeds residents. The overriding aim of the evaluation was to inform the operation of possible future schemes, with good practices and any issues identified. The views of organisations on the need for the funds and how the campaign was organised were ascertained. How they delivered the services, reached clients and worked with other stakeholders is explored and their suggestions for improvements described. This report should be read alongside the overall campaign report, by Leeds City Council, and the beneficiary report
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