oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 31 )

2018 ( 189 )

2017 ( 218 )

2016 ( 343 )

Custom range...

Search Results: 1 - 10 of 204125 matches for " Adrian P; Cerrolaza "
All listed articles are free for downloading (OA Articles)
Page 1 /204125
Display every page Item
Aplicación de la ecuación integral de contorno axisimétrica para elasticidad y termoelasticidad
González,Yomar A; Cisilino,Adrian P; Cerrolaza,Miguel E;
Boletín Técnico , 2007,
Abstract: dealing with axisymmetric problems involves a co-ordinate transformation system and additional integration process of the well-known classic boundary integral equation for 3d elasticity and thermoelasticity theories. an axisymmetric boundary element formulation is implemented in a steady-state framework for multi-domain elastic, isotropic and homogeneous problems. the fundamental solutions and their singular behaviour were taken from available literature. in order to obtain a high accuracy in the solution, employing continuous linear elements, some singular terms appearing in the boundary integral equation have been integrated analytically. several numerical examples are provided to illustrate de versatility of this approach for practical engineering problems
Aplicación de la ecuación integral de contorno axisimétrica para elasticidad y termoelasticidad Bem axisymmetric formulation for elasticity and thermoelasticity
Yomar A González,Adrian P Cisilino,Miguel E Cerrolaza
Boletín Técnico , 2007,
Abstract: Para el tratamiento de problemas con simetría axial, la ecuación integral de contorno para elasticidad y/o termoelasticidad en 3D sufre una transformación de coordenadas y un proceso de integración adicional para generar las soluciones axisimétricas requeridas. Este trabajo presenta la implementación de las soluciones axisimétricas para el estudio de problemas definidos en un medio elástico-lineal, isótropo, homogéneo y en régimen estacionario, en un código de Elementos de Contorno multi zona. Las expresiones analíticas de las soluciones y el desarrollo asintótico de las mismas fueron extraídas de la literatura. Para mantener un alto grado de exactitud en la solución usando elementos lineales isoparamétricos, algunos términos singulares contenidos en la ecuación integral de contorno fueron integrados analíticamente. La nueva herramienta es aplicada a diferentes ejemplos con solución analítica conocida, cotejando los resultados y comprobando la precisión y eficacia del código Dealing with axisymmetric problems involves a co-ordinate transformation system and additional integration process of the well-known classic boundary integral equation for 3D elasticity and thermoelasticity theories. An axisymmetric boundary element formulation is implemented in a steady-state framework for multi-domain elastic, isotropic and homogeneous problems. The fundamental solutions and their singular behaviour were taken from available literature. In order to obtain a high accuracy in the solution, employing continuous linear elements, some singular terms appearing in the boundary integral equation have been integrated analytically. Several numerical examples are provided to illustrate de versatility of this approach for practical engineering problems
An Integral Representation of a Family of Slit Mappings  [PDF]
Adrian W. Cartier, Michael P. Sterner
Advances in Pure Mathematics (APM) , 2012, DOI: 10.4236/apm.2012.23028
Abstract: We consider a normalized family F of analytic functions f, whose common domain is the complement of a closed ray in the complex plane. If f(z) is real when z is real and the range of f does not intersect the nonpositive real axis, then f can be reproduced by integrating the biquadratic kernel against a probability measure u(t) . It is shown that while this integral representation does not characterize the family F, it applies to a large class of functions, including a collection of functions which multiply the Hardy space Hp into itself.
Finite element analysis of the indentation test on rocks with microstructure
Jean Sulem,Miguel Cerrolaza
Physics , 2008,
Abstract: Strength parameters of rocks are currently determined from indentation tests. In this paper, a finite element analysis of this test is presented and scale effect is studied. The rock is modelled as an elasto-plastic medium with Cosserat microstructure and consequently possesses an internal length. The response of the indentation curve is studied for various values of the size of the indentor as compared to the internal length of the rock in order to assess the scale effect.
Fredholm Determinant of an Integral Operator Driven by a Diffusion Process
Adrian P. C. Lim
International Journal of Stochastic Analysis , 2008, DOI: 10.1155/2008/130940
Abstract: This article aims to give a formula for differentiating, with respect to , an expression of the form (,)∶=[()?∫0()(det(
Towards a Unified Understanding of Event-Related Changes in the EEG: The Firefly Model of Synchronization through Cross-Frequency Phase Modulation
Adrian P. Burgess
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045630
Abstract: Although event-related potentials (ERPs) are widely used to study sensory, perceptual and cognitive processes, it remains unknown whether they are phase-locked signals superimposed upon the ongoing electroencephalogram (EEG) or result from phase-alignment of the EEG. Previous attempts to discriminate between these hypotheses have been unsuccessful but here a new test is presented based on the prediction that ERPs generated by phase-alignment will be associated with event-related changes in frequency whereas evoked-ERPs will not. Using empirical mode decomposition (EMD), which allows measurement of narrow-band changes in the EEG without predefining frequency bands, evidence was found for transient frequency slowing in recognition memory ERPs but not in simulated data derived from the evoked model. Furthermore, the timing of phase-alignment was frequency dependent with the earliest alignment occurring at high frequencies. Based on these findings, the Firefly model was developed, which proposes that both evoked and induced power changes derive from frequency-dependent phase-alignment of the ongoing EEG. Simulated data derived from the Firefly model provided a close match with empirical data and the model was able to account for i) the shape and timing of ERPs at different scalp sites, ii) the event-related desynchronization in alpha and synchronization in theta, and iii) changes in the power density spectrum from the pre-stimulus baseline to the post-stimulus period. The Firefly Model, therefore, provides not only a unifying account of event-related changes in the EEG but also a possible mechanism for cross-frequency information processing.
Measuring Consultant Radiologist workload: method and results from a national survey
Adrian P. Brady
Insights into Imaging , 2011, DOI: 10.1007/s13244-011-0094-3
Abstract: Irish Consultant Radiologist staffing levels are well below appropriate international benchmarks for the current workload. Approximately one-third of radiologist time is engaged in activity not easily counted in study numbers.
Simplicial Brill wave initial data
Adrian P. Gentle
Physics , 1999, DOI: 10.1088/0264-9381/16/6/327
Abstract: Regge calculus is used to construct initial data for vacuum axisymmetric Brill waves at a moment of time symmetry. We argue that only a tetrahedral lattice can successfully reproduce the continuum solution, and develop a simplicial axisymmetric lattice based on the co-ordinate structure of the continuum metric. This is used to construct initial data for Brill waves in an otherwise flat spacetime, and for the distorted black hole spacetime of Bernstein. These initial data sets are shown to be second order accurate approximations to the corresponding continuum solutions.
The BSSN formulation is a partially constrained evolution system
Adrian P. Gentle
Physics , 2007, DOI: 10.1142/S0218271810016312
Abstract: Relativistic simulations in 3+1 dimensions typically monitor the Hamiltonian and momentum constraints during evolution, with significant violations of these constraints indicating the presence of instabilities. In this paper we rewrite the momentum constraints as first-order evolution equations, and show that the popular BSSN formulation of the Einstein equations explicitly uses the momentum constraints as evolution equations. We conjecture that this feature is a key reason for the relative success of the BSSN formulation in numerical relativity.
Regge calculus: a unique tool for numerical relativity
Adrian P. Gentle
Physics , 2004,
Abstract: The application of Regge calculus, a lattice formulation of general relativity, is reviewed in the context of numerical relativity. Particular emphasis is placed on problems of current computational interest, and the strengths and weaknesses of the lattice approach are highlighted. Several new and illustrative applications are presented, including initial data for the head on collision of two black holes, and the time evolution of vacuum axisymmetric Brill waves.
Page 1 /204125
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.