3 resultados para Penrose limit and pp-wave background

em Greenwich Academic Literature Archive - UK


Relevância:

100.00% 100.00%

Publicador:

Resumo:

An MHD flow is considered which is relevant to horizontal Bridgman technique for crystal growth from a melt. In the unidirectional parallel flow approximation an analytical solution is found accounting for the finite rectangular cross section of the channel in the case of a vertical magnetic field. Numerical pseudo-spectral solutions are used in the cases of arbitrary magnetic field and gravity vector orientations. The vertical magnetic field (parallel to the gravity) is found to be he most effective to damp the flow, however, complicated flow profiles with "overvelocities" in the comers are typical in the case of a finite cross-section channel. The temperature distribution is shown to be dependent on the flow profile. The linear stability of the flow is investigated by use of the Chebyshev pseudospectral method. For the case of an infinite width channel the transversal rolls instability is investigated, and for the finite cross-section channel the longitudinal rolls instability is considered. The critical Gr number values are computed in the dependence of the Ha number and the wave number or the aspect ratio in the case of finite section.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The performance of the register insertion protocol for mixed voice-data traffic is investigated by simulation. The simulation model incorporates a common insertion buffer for station and ring packets. Bandwidth allocation is achieved by imposing a queue limit at each node. A simple priority scheme is introduced by allowing the queue limit to vary from node to node. This enables voice traffic to be given priority over data. The effect on performance of various operational and design parameters such as ratio of voice to data traffic, queue limit and voice packet size is investigated. Comparisons are made where possible with related work on other protocols proposed for voice-data integration. The main conclusions are: (a) there is a general degradation of performance as the ratio of voice traffic to data traffic increases, (b) substantial improvement in performance can be achieved by restricting the queue length at data nodes and (c) for a given ring utilisation, smaller voice packets result in lower delays for both voice and data traffic.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

EXECUTIVE SUMMARY Aims 1. The aims of this strategy are • to ensure that a full range of education and training related to the adult end of life care pathway is available across South East London to meet the needs of our health and social care workforce • to enable those responsible for end of life care education and training commissioning to procure comprehensively from a full range of education providers in a systematic and strategic manner. Background 2. The work that underpins this strategy was begun by the South East London Cancer Network via its Palliative and End of Life Care Coordinating Group and then developed by way of the Marie Curie Delivering Choice Programme’s Education and Training work stream.