22,208 research outputs found
Propellant slosh coupling with bending Interim report
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
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
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
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Widespread evidence for heterogeneous accretion of the terrestrial planets and planetisimals
The abundance and relative proportion of highly siderophile elements (HSEs) in Earth’s mantle deviate from those predicted by low-pressure equilibrium partitioning between metal and silicate during formation of the core. For many elements, high-pressure equilibration in a deep molten silicate layer (or ‘magma ocean’) may account for this discrepancy [1], but some highly siderophile element abundances demand the late addition, a ‘late veneer’, of extraterrestrial material (i.e. heterogeneous accretion) after core formation was complete [2]. Siderophile elements in smaller asteroidal bodies will not be affected by high-pressure metal-silicate equilibration and so, with highly efficient core formation [3] and if a ‘late veneer’ is absent, significant differences in the proportions of HSEs can be anticipated. Here we present new HSE abundance and 187Os/188Os isotope data for basaltic meteorites, the HEDs (howardites, eucrites and diogenites thought to sample the asteroid 4 Vesta), anomalous eucrites (considered to be from distinct Vesta-like parent bodies) angrites and aubrites (from unidentified parent bodies) and SNCs (thought to be from Mars). Our data, taken with those for lunar rocks [4], demonstrate that these igneous meteorites all formed from mantle sources that possessed chondritic (i.e. primitive solar system) elemental and isotope compositions, indicating that late accretion is not unique to Earth, but is a common feature of differentiated planets and asteroidal bodies. Variations in the total HSE abundance suggest that the proportion of ‘late veneer’ added is a simple consequence of the size of each body (cross-section and/or gravitational-attraction), and may account for the volatile element budget, and the oxidationstate of Earth, Mars, the Moon and Vesta
On the accuracy of retrieved wind information from Doppler lidar observations
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
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
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
Dynamic structural behavior of large rocket booster synthesized by two thin-walled cylinders and subjected to periodically varying end thrus
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The <i>AKARI</i> deep fields: early results from multi-wavelength follow-up campaigns
We present early results from our multi-wavelength follow-up campaigns of the AKARI Deep Fields at the North and South Ecliptic Poles. We summarize our campaigns in this poster paper, and present three early outcomes. (a) Our AAOmega optical spectroscopy of the Deep Field South at the AAT has observed over 550 different targets, and our preliminary local luminosity function at 90 ?m from the first four hours of data is in good agreement with the predictions from Serjeant & Harrison (2005). (b) Our GMRT 610 MHz imaging in the Deep Field North has reached ?30 ?Jy RMS, making this among the deepest images at this frequency. Our 610 MHz source counts at >200 ?Jy are the deepest ever derived at this frequency. (c) Comparing our GMRT data with our 1.4 GHz WSRT data, we have found two examples of radio-loud AGN that may have more than one epoch of activity
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