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Hazeleger W.,Royal Netherlands Meteorological Institute | Severijns C.,Royal Netherlands Meteorological Institute | Semmler T.,Met Eireann | Stefanescu S.,European Center for Medium Range Weather Forecasts | And 29 more authors.
Bulletin of the American Meteorological Society | Year: 2010

The EC-Earth consortium is a grouping of meteorologists and Earth-system scientists from 10 European countries, put together to face the challenges of climate and weather forecasting. The NWP system of the European Centre for Medium-Range Weather Forecasts (ECWMF) forms the basis of the EC-Earth Earth-system model. NWP models are designed to accurately capture short-term atmospheric fluctuations. They are used for forecasts at daily-to-seasonal time scales and include data assimilation capabilities. Climate models are designed to represent the global coupled ocean-atmosphere system. The atmospheric model of EC-Earth version 2, is based on ECMWF's Integrated Forecasting System (IFS), cycle 31R1, corresponding to the current seasonal forecast system of ECMWF. The EC-Earth consortium and ECMWF are collaborating on development of initialization procedures to improve long-term predictions. The EC-Earth model displays good performance from daily up to inter-annual time scales and for long-term mean climate.

Stops A.J.F.,National University of Ireland | Heraty K.B.,National University of Ireland | Browne M.,Irish Center for High End Computing | O'Brien F.J.,Royal College of Surgeons in Ireland | And 2 more authors.
Journal of Biomechanics | Year: 2010

Mesenchymal stem cell (MSC) differentiation can be influenced by biophysical stimuli imparted by the host scaffold. Yet, causal relationships linking scaffold strain magnitudes and inlet fluid velocities to specific cell responses are thus far underdeveloped. This investigation attempted to simulate cell responses in a collagen-glycosaminoglycan (CG) scaffold within a bioreactor. CG scaffold deformation was simulated using μ-computed tomography (CT) and an in-house finite element solver (FEEBE/. linear). Similarly, the internal fluid velocities were simulated using the afore-mentioned μCT dataset with a computational fluid dynamics solver (ANSYS/CFX). From the ensuing cell-level mechanics, albeit octahedral shear strain or fluid velocity, the proliferation and differentiation of the representative cells were predicted from deterministic functions. Cell proliferation patterns concurred with previous experiments. MSC differentiation was dependent on the level of CG scaffold strain and the inlet fluid velocity. Furthermore, MSC differentiation patterns indicated that specific combinations of scaffold strains and inlet fluid flows cause phenotype assemblies dominated by single cell types. Further to typical laboratory procedures, this predictive methodology demonstrated loading-specific differentiation lineages and proliferation patterns. It is hoped these results will enhance in-vitro tissue engineering procedures by providing a platform from which the scaffold loading applications can be tailored to suit the desired tissue. © 2009 Elsevier Ltd.

Many solid-state devices such as SATA and PCIe interface are evolving significantly. The low-end SSD drives cost around $1.50 per gigabyte. Gartner predicts SSD prices will drop to a dollar per gigabyte in 2012. Switching a 320 GB hard disk drive to a smaller capacity 256 GB SSD disk when purchasing an Apple MacBook Pro will add $650 to the price of a system. The cachet in caching is that enterprise customers see the performance benefits of SSD without paying for an all solid-state storage solution. Storage arrays can use solid-state storage dynamically like a large power-safe cache. Active data that creates a hot-spot of frequent accesses in the storage array can be transparently moved from mechanical disk to solid-state disk. The requirement is that the active data such as hot spot fit inside the available high-speed SSD storage. The hot-spots can be dynamically migrated on and off the expensive, fast storage to best maintain high storage performance.

Harrison N.M.,National University of Ireland | McDonnell P.,National University of Ireland | Mullins L.,National University of Ireland | Wilson N.,Irish Center for High End Computing | And 2 more authors.
Biomechanics and Modeling in Mechanobiology | Year: 2013

Trabecular bone tissue failure can be considered as consisting of two stages: damage and fracture; however, most failure analyses of 3D high-resolution trabecular bone samples are confined to damage mechanisms only, that is, without fracture. This study aims to develop a computational model of trabecular bone consisting of an explicit representation of complete failure, incorporating damage criteria, fracture criteria, cohesive forces, asymmetry and large deformation capabilities. Following parameter studies on a test specimen, and experimental testing of bone sample to complete failure, the asymmetric critical tissue damage and fracture strains of ovine vertebral trabecular bone were calibrated and validated to be compression damage -1.16 %, tension damage 0.69 %, compression fracture -2.91 % and tension fracture 1.98 %. Ultimate strength and post-ultimate strength softening were captured by the computational model, and the failure of individual struts in bending and shear was also predicted. This modelling approach incorporated a cohesive parameter that provided a facility to calibrate ductile-brittle behaviour of bone tissue in this non-linear geometric and non-linear constitutive property analyses tool. Finally, the full accumulation of tissue damage and tissue fracture has been monitored from range of small magnitude (normal daily loading) through to specimen yielding, ultimate strength and post-ultimate strength softening. © 2012 Springer-Verlag.

Brown A.C.,Queens University of Belfast | Hutchinson S.,Queens University of Belfast | Lysaght M.A.,Irish Center for High End Computing | Van Der Hart H.W.,Queens University of Belfast
Physical Review Letters | Year: 2012

We investigate the influence of the autoionizing 3s3p6n ℓ resonances on the fifth harmonic generated by 200-240 nm laser fields interacting with Ar. To determine the influence of a multielectron response we develop the capability within time-dependent R-matrix theory to determine the harmonic spectra generated. The fifth harmonic is affected by interference between the response of a 3s electron and the response of a 3p electron, as demonstrated by the asymmetric profiles in the harmonic yields as functions of wavelength. © 2012 American Physical Society.

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