Albedos and diameters of three Mars Trojan asteroids   总被引：1，自引：1，他引：0  

David E. Trilling  Andrew S. Rivkin  John A. Stansberry  Timothy B. Spahr  Richard A. Crudo  John K. Davies 《Icarus》2007,192(2):442-447

We observed the Mars Trojan Asteroids (5261) Eureka and (101429) 1998 VF₃₁ and the candidate Mars Trojan 2001 FR₁₂₇ at 11.2 and 18.1 microns using Michelle on the Gemini North telescope. We derive diameters of 1.28, 0.78, and <0.52 km, respectively, with corresponding geometric visible albedos of 0.39, 0.32, and >0.14. The albedos for Eureka and 1998 VF₃₁ are consistent with the taxonomic classes and compositions (S(I)/angritic and S(VII)/achondritic, respectively) and implied histories presented in a companion paper by Rivkin et al. Eureka's surface likely has a relatively high thermal inertia, implying a thin regolith that is consistent with predictions and the small size that we derive.  相似文献   

Where do experiments end?     

Gail Davies 《Geoforum》2010,41(5):667-670

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Neutron star retention and millisecond pulsar production in globular clusters     

Melvyn B. Davies  & Brad M. S. Hansen 《Monthly notices of the Royal Astronomical Society》1998,301(1):15-24

We investigate the conditions by which neutron star retention in globular clusters is favoured. We find that neutron stars formed in massive binaries are far more likely to be retained. Such binaries are likely to then evolve into contact before encountering other stars, possibly producing a single neutron star after a common envelope phase. A large fraction of the single neutron stars in globular clusters are then likely to exchange into binaries containing moderate-mass main-sequence stars, replacing the lower-mass components of the original systems. These binaries will become intermediate-mass X-ray binaries (IMXBs), once the moderate-mass star evolves off the main sequence, as mass is transferred on to the neutron star, possibly spinning it up in the process. Such systems may be responsible for the population of millisecond pulsars (MSPs) that has been observed in globular clusters. Additionally, the period of mass-transfer (and thus X-ray visibility) in the vast majority of such systems will have occurred 5–10 Gyr ago, thus explaining the observed relative paucity of X-ray binaries today, given the MSP population.  相似文献   

The AMADEUS dextrous subsea hand: design, modeling, and sensorprocessing     

Lane  D.M. Davies  J.B.C. Robinson  G. O'Brien  D.J. Sneddon  J. Seaton  E. Elfstrom  A. 《Oceanic Engineering, IEEE Journal of》1999,24(1):96-111

This paper describes the mechanical design, finger modeling, and sensor signal processing for a dextrous subsea robot hand incorporating force and slip contact sensing. The hand uses a fluid-filled tentacle for each finger, which has inherent passive compliance, and no moving parts. Force sensing uses strain gauges mounted in the fingertip, potted within a silicon elastomer. Slip sensing uses a piezoelectric strip to detect vibration, embedded 1 mm below the elastomer surface. Static models of finger motion are presented and validated based on bending moments and hydraulic pressure. The design of a stochastic estimator is also described for sensor fusion of contact force magnitude and direction data, obtained using redundant strain gauges in the fingertip. Finally, linear dynamic models of the finger dynamics in contact with a rigid surface are obtained using least squares and recursive least squares parameter estimation, as a precursor to closed-loop force control during grasping  相似文献   

Cleantech clusters: Transformational assemblages for a just,green economy or just business as usual?     

Anna R. Davies 《Global Environmental Change》2013,23(5):1285-1295

The rhetorical zeal for green enterprise as a global fix for the tripartite challenges of economic recession, environmental degradation and social inequality is increasingly visible in state and non-state pronouncements around the globe under the banner of ‘The Green Economy’. In particular, many policy-facing statements call for transitions leading to a transformation in development practices. Yet there is little detail either in policy or research regarding the types of transitions needed and how they are to be initiated, nor agreement about what a transformed economy might look like. Despite this, there are emergent activities within the cleantech arena which are being heralded as actually existing examples of green economy activities. One means through which these activities are seeking to exert influence over development trajectories is by clustering both at the subnational and transnational level. While diverse in formation, many of these clusters are hybridised, involving actors from public, private and civil society sectors. Critiquing the efficacy of mainstream industrial cluster theory to analyse hybridised cleantech clustering, this paper presents a unique synthesis of current thought on multiscalar environmental governance and socio-spatial formations to explore the practices and potentialities of these hybridised cleantech clusters. Surveying the landscape of cleantech clustering and meta-clustering, before focusing in depth on one case study, the contribution of clustering to transitioning towards a transformed green economy is considered. Despite strong forces, both within and beyond cleantech clusters, for maintaining neoliberalised approaches to cleantech activity, it is concluded that for as long as cleantech clusters remain open and inclusive of actors proposing alternative pathways they do represent potential, albeit provisional, assemblages for transformation.  相似文献   

LATENT MIGRATION POTENTIAL AND SPACE PREFERENCES     

Wayne K. D. Davies 《The Professional geographer》1966,18(5):300-304

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JHK observations of faint standard stars in the Mauna Kea Observatories near-infrared photometric system     

S. K. Leggett  M. J. Currie  W. P. Varricatt  T. G. Hawarden  A. J. Adamson  J. Buckle  T. Carroll  J. K. Davies  C. J. Davis  T. H. Kerr  O. P. Kuhn  M. S. Seigar  T. Wold 《Monthly notices of the Royal Astronomical Society》2006,373(2):781-792

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Optical/near-infrared colours of early-type galaxies and constraints on their star formation histories     

P. A. James  M. Salaris  J. I. Davies  S. Phillipps  S. Cassisi 《Monthly notices of the Royal Astronomical Society》2006,367(1):339-348

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Structural properties of discs and bulges of early-type galaxies     

Roelof S. de Jong  Luc Simard  Roger L. Davies  R. P. Saglia  David Burstein  Matthew Colless  Robert McMahan  Gary Wegner 《Monthly notices of the Royal Astronomical Society》2004,355(4):1155-1170

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Young stars in the Galactic Centre: a potential intermediate-mass star origin     

L. M. Dray  A. R. King  M. B. Davies 《Monthly notices of the Royal Astronomical Society》2006,372(1):31-44

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