2,428 research outputs found
High resolution absolute flux profiles of the MC 2 h and k lines in evolved F8 to M5 stars
The central results of a survey of the Mg II resonance line emission in a sample of over 50 evolved late type stars, including spectral-luminosity type F8 to M5 and La to IV are presented. Observed and surface fluxes are derived and correlations noted. The major findings include: (1) Mg II k emission core asymmetry transition near K1 III, analogous to that known for Ca II K; (2) a small gravity and temperature dependence of the Mg II chromospheric radiative loss rate
Making automation pay - cost & throughput trade-offs in the manufacture of large composite components
The automation of complex manufacturing operations can provide significant savings over manual processes, and there remains much scope for increasing automation in the production of large scale structural composites. However the relationships between driving variables are complex, and the achievable throughput rate and corresponding cost for a given design are often not apparent. The deposition rate, number of machines required and unit production rates needed are interrelated and consequently the optimum unit cost is difficult to predict. A detailed study of the costs involved for a series of composite wing cover panels with different manufacturing requirements was undertaken. Panels were sized to account for manufacturing requirements and structural load requirements allowing both manual and automated lay-up procedures to influence design. It was discovered that the introduction of automated tape lay-up can significantly reduce material unit cost, and improve material utilisation, however higher production rates are needed to see this benefit
Current welfare problems facing horses in Great Britain as identified by equine stakeholders
This is the final version of the article. Available from the publisher via the DOI in this record.Despite growing concerns about the welfare of horses in Great Britain (GB) there has been
little surveillance of the welfare status of the horse population. Consequently we have limited
knowledge of the range of welfare problems experienced by horses in GB and the situations
in which poor welfare occurs. Thirty-one in-depth interviews were conducted with a
cross -section of equine stakeholders, in order to explore their perceptions of the welfare
problems faced by horses in GB. Welfare problems relating to health, management and riding
and training were identified, including horses being under or over weight, stabling 24
hours a day and the inappropriate use of training aids. The interviewees also discussed
broader contexts in which they perceived that welfare was compromised. The most commonly
discussed context was where horses are kept in unsuitable environments, for example
environments with poor grazing. The racing industry and travellers horses were
identified as areas of the industry where horse welfare was particularly vulnerable to compromise.
Lack of knowledge and financial constraints were perceived to be the root cause
of poor welfare by many interviewees. The findings give insight into the range of welfare
problems that may be faced by horses in GB, the contexts in which these may occur and
their possible causes. Many of the problems identified by the interviewees have undergone
limited scientific investigation pointing to areas where further research is likely to be necessary
for welfare improvement. The large number of issues identified suggests that some
form of prioritisation may be necessary to target research and resources effectivelyThe research was funded by World Horse
Welfare: http://www.worldhorsewelfare.org/Home
Grant code: DFAS SJ1045
Homogenisation and analysis of an expanded long-term monthly rainfall network for the Island of Ireland (1850-2010)
Long-term precipitation series are critical for understanding emerging changes to the hydrological cycle. To this end we construct a homogenised Island of Ireland Precipitation (IIP) network comprising 25 stations and a composite series covering the period 1850-2010, providing the second- longest regional precipitation archive in the British-Irish Isles. We expand the existing catalogue of long-term precipitation records for the island by recovering archived data for an additional eight stations. Following bridging and updating of stations HOMER homogenisation software is used to detect breaks using pairwise and joint detection. Twenty-five breakpoints are detected across 14 stations, and the majority (20) are corroborated by metadata. Assessment of variability and change in homogenised and extended precipitation records reveal positive (winter) and negative (summer) trends. Trends in records covering the typical period of digitisation (1941 onwards) are not always representative of longer records. Furthermore, trends in post-homogenisation series change magnitude and even direction at some stations. While cautionary flags are raised for some series, confidence in the derived network is high given attention paid to metadata, coherence of behaviour across the network and consistency of findings with other long-term climatic series such as England and Wales precipitation. As far as we are aware, this work represents the first application of HOMER to a long- term precipitation network and bodes well for use in other regions. It is expected that the homogenised IIP network will find wider utility in benchmarking and supporting climate services across the Island of Ireland, a sentinel location in the North Atlantic
MHD‐driven kinetic dissipation in the solar wind and corona
Mechanisms for the deposition of heat in the lower coronal plasma are discussed, emphasizing recent attempts to reconcile the fluid and kinetic perspectives. Structures at magnetohydrodynamic (MHD) scales may drive a nonlinear cascade, preferentially exciting high perpendicular wavenumber fluctuations. Relevant dissipative kinetic processes must be identified that can absorb the associated energy flux. The relationship between the MHD cascade and direct cyclotron absorption, including cyclotron sweep, is discussed. We conclude that for coronal and solar wind parameters the perpendicular cascade cannot be neglected and may be more rapid than cyclotron sweep. Solar wind observational evidence suggests the relevance of the ion inertial scale, which is associated with current sheet thickness during reconnection. We conclude that a significant fraction of dissipation in the corona and solar wind likely proceeds through a perpendicular cascade and small-scale reconnection, coupled to kinetic processes that act at oblique wavevectors
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