21,905 research outputs found

    Propellant slosh coupling with bending Interim report

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    Vibrational characteristics of large liquid propellant space vehicl

    Vibration of a circular cylindrical elastic tank, partially filled with an incompressible fluid, undergoing an axial acceleration composed of a uniform and a periodic component technical memorandum no. 102

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    Forced vibration of circular cylindrical elastic shell partially filled with incompressible liquid and initially at rest in uniform gravitational fiel

    The development of direct payments in the UK: implications for social justice

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    Direct payments have been heralded by the disability movement as an important means to achieving independent living and hence greater social justice for disabled people through enhanced recognition as well as financial redistribution. Drawing on data from the ESRC funded project Disabled People and Direct Payments: A UK Comparative Perspective, this paper presents an analysis of policy and official statistics on use of direct payments across the UK. It is argued that the potential of direct payments has only partly been realised as a result of very low and uneven uptake within and between different parts of the UK. This is accounted for in part by resistance from some Labour-controlled local authorities, which regard direct payments as a threat to public sector jobs. In addition, access to direct payments has been uneven across impairment groups. However, from a very low base there has been a rapid expansion in the use of direct payments over the past three years. The extent to which direct payments are able to facilitate the ultimate goal of independent living for disabled people requires careful monitoring

    On the accuracy of retrieved wind information from Doppler lidar observations

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    A single pulsed Doppler lidar was successfully deployed to measure air flow and turbulence over the Malvern hills, Worcester, UK. The DERA Malvern lidar used was a CO2 µm pulsed Doppler lidar. The lidar pulse repetition rate was 120 Hz and had a pulse duration of 0.6 µs The system was set up to have 41 range gates with range resolution of 112 m. This gave a theoretical maximum range of approximately 4.6 km. The lidar site was 2 km east of the Malvern hill ridge which runs in a north-south direction and is approximately 6 km long. The maximum height of the ridge is 430 m. Two elevation scans (Range-Height Indicators) were carried out parallel and perpendicular to the mean surface flow. Since the surface wind was primarily westerly the scans were carried out perpendicular and parallel to the ridge of the Malvern hills. The data were analysed and horizontal winds, vertical winds and turbulent fluxes were calculated for profiles throughout the boundary layer. As an aid to evaluating the errors associated with the derivation of velocity and turbulence profiles, data from a simple idealized profile was also analysed using the same method. The error analysis shows that wind velocity profiles can be derived to an accuracy of 0.24 m s-1 in the horizontal and 0.3 m s-1 in the vertical up to a height of 2500 m. The potential for lidars to make turbulence measurements, over a wide area, through the whole depth of the planetary boundary layer and over durations from seconds to hours is discussed

    A multi-wavelength view of galaxy evolution with AKARI

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    AKARI's all-sky survey resolves the far-infrared emission in many thousands of nearby galaxies, providing essential local benchmarks against which the evolution of high-redshift populations can be measured. This review presents some recent results in the resolved galaxy populations, covering some well-known nearby targets, as well as samples from major legacy surveys such as the Herschel Reference Survey and the JCMT Nearby Galaxies Survey. This review also discusses the prospects for higher redshifts surveys, including strong gravitational lens clusters and the AKARI NEP field.Comment: Accepted for Publications of the Korean Astronomical Society (September 30, 2012 issue, volume 27, No. 3), Proceedings of the Second AKARI conference, Legacy of AKARI: A Panoramic View of the Dusty Universe. 6 page

    Measurements of Specific Heats by a Pulse Method

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    Calorimetric methods of measuring specific heats at high temperatures are slow and often involve laborious precautions to eliminate heat losses. Pulse heating methods are rapid and heat losses can be made negligible. The accuracy of the calorimetric methods, however, has been greater than that of the pulse heating methods, which need further development. The purpose of the present investigation was to develop further and to evaluate again one of the more promising pulse heating methods. Kurrelmeyer, Mais and Green (1) suggested in 1941 the use of pulse heating. Baxter (2) described in 1944 a pulse method in which the current and voltage across a thin wire sample were recorded simultaneously. This information, combined with knowledge of the resistance as a function of temperature, gave the specific heat. The principle of Baxter\u27s method has been used in preliminary measurements by Khotkovitch and Bagrov (3) and by Nathahn (4), and is also used in this investigation

    Dynamic stability of a flexible booster subjected to a gimbled, periodically-varying end thrust Technical memorandum no. 104

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    Dynamic structural behavior of large rocket booster synthesized by two thin-walled cylinders and subjected to periodically varying end thrus
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