Solution of hyperbolic bioheat conduction models based on adaptive time integrators

In this work, a new time marching technique is proposed to analyze hyperbolic bioheat transfer problems. In this new approach, time integration parameters adapt themselves along the solution process, in accordance to the properties and results of the model. Thus, the time integrators are locally evaluated, assuming different values along the spatial and temporal discretizations, enabling a more accurate and effective solution algorithm. The proposed technique has guaranteed stability, it is truly self-starting, and it is formulated as a non-iterative single-step/solver procedure, demanding low computational efforts. As illustrated in the manuscript, the methodology is very accurate, robust and simple to implement, providing a suitable numerical approach to analyze hyperbolic bioheat conduction models

A coupled BEM/FEM formulation for drop interaction in stokes flows with flexible and slip confining boundaries

In this work, fluid-fluid-solid coupled models are analysed, considering the interaction of boundary and finite element techniques. In this context, the paper focuses on the study of deforming drops through bulk fluids bounded by flexible walls. Here, the fluid subdomains are assumed to be viscous and incompressible, and they are modelled by the BEM. The solid subdomains are assumed to be elastic, and they are modelled by the FEM. Both discontinuity of tractions on the fluid-fluid common boundaries and discontinuity of velocities on the fluid-solid interfaces are considered. For the discontinuity of velocities, a formulation based on nonlinear slip boundary conditions is adopted, which is treated employing a relaxed iterative approach. A Lagrangian representation is considered and remeshing is applied on the fluid-fluid interfaces, reducing the appearance of numerical problems. Numerical results are presented to illustrate the performance and potentialities of the proposed techniques.The financial support from CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), FAPEMIG (Fundação de Amparo à Pesquisa do Estado de Minas Gerais) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), Brazil, is gratefully acknowledged

ADAPTIVE ITERATIVE BEM-FEM COUPLING PROCEDURES TO ANALYZE INELASTIC MODELS

The analysis of complex systems may be more effectively handled considering the combination of different numerical methods, in a way that each numerical technique can be applied to deal with the particularities of the model that better fit its positive features. In this sense, the adaptive iterative coupling of the Boundary Element Method (BEM) and of the Finite Element Method (FEM) is discussed here, taking into account static nonlinear models. Optimal relaxation parameters are employed to speed up the convergence of the iterative coupling, and non-matching discretizations at common interfaces, as well as adaptive refinement within the FEM subdomains, are allowed, enabling more versatile and accurate approaches. A single unified iterative loop is considered in order to deal with all the focused iterative solutions simultaneously (i.e., the nonlinear analysis, the adaptive analysis and the coupling analysis), rendering a very efficient methodology. In this context, multiple sequential iterative loops, which represent a rather computationally demanding approach, can be avoided without significantly increase the number of the iterative steps of the dominant iterative process, considerably improving the performance of the method. At the end of the paper, numerical results are presented, illustrating the potentialities and the effectiveness of the proposed techniques.&nbsp

An efficient multi-time step FEM–SFEM iterative coupling procedure for elastic–acoustic interaction problems

An iterative coupling methodology between the Finite Element Method (FEM) and the Spectral Finite Element Method (SFEM) for the modeling of coupled elastic-acoustic problems in the time domain is presented here. Since the iterative coupling procedure allows the use of a nonconforming mesh at the interface between the subdomains, the difference in the element sizes concerning the FEM and SFEM is handled in a straightforward and efficient manner, thereby retaining all the advantages of the SFEM. By means of the HHT time integration method, controllable numerical damping can be introduced in one of the subdomains, increasing the robustness of the method and improving the accuracy of the results; besides, independent time-step sizes can be considered within each subdomain, resulting in a more efficient algorithm. In this work, a modification in the subcycling procedure is proposed, ensuring not only an efficient and accurate methodology but also avoiding the computation of a relaxation parameter. Numerical simulations are presented in order to illustrate the accuracy and potential of the proposed methodology.CAPES, UFJF, UFSJ, FAPEMIG and CNP

Tricritical Points in the Sherrington-Kirkpatrick Model in the Presence of Discrete Random Fields

The infinite-range-interaction Ising spin glass is considered in the presence of an external random magnetic field following a trimodal (three-peak) distribution. The model is studied through the replica method and phase diagrams are obtained within the replica-symmetry approximation. It is shown that the border of the ferromagnetic phase may present first-order phase transitions, as well as tricritical points at finite temperatures. Analogous to what happens for the Ising ferromagnet under a trimodal random field, it is verified that the first-order phase transitions are directly related to the dilution in the fields (represented by $p_{0}$). The ferromagnetic boundary at zero temperature also exhibits an interesting behavior: for $0<p_{0}<p_{0}^{*} \approx 0.30856$, a single tricritical point occurs, whereas if $p_{0}>p_{0}^{*}$ the critical frontier is completely continuous; however, for $p_{0}=p_{0}^{*}$, a fourth-order critical point appears. The stability analysis of the replica-symmetric solution is performed and the regions of validity of such a solution are identified; in particular, the Almeida-Thouless line in the plane field versus temperature is shown to depend on the weight $p_{0}$.Comment: 23pages, 7 ps figure

Lanthanide compounds containing a benzo-15-crown-5 derivatised [60]fullerene and the related [Tb(H2O)(3)(NO3)(2)(acac)]. C14H20O5 supramolecular adduct

Novel lanthanum(III), europium(III) and terbium(III) compounds of a benzo-15-crown-5 [60]fulleropyrrolidine were isolated in the solid state and characterised using vibrational (infrared and Raman) spectroscopy and by 13C CP MAS NMR for the lanthanum(III) compound. The photoluminescence properties were investigated for the europium(III) and terbium(III) compounds. The related [Tb(H2O)3(NO3)2(acac)] C14H20O5 [where acac ¼ acetylacetonate and C14H20O5 ¼ benzo-15-crown-5] supramolecular adduct was isolated using similar synthetic conditions, in the absence of [60]fullerene, and its crystal structure used as a model for the coordination sphere of the lanthanide [60]fullerene derivatives, with further supporting evidence given by photoluminescence measurements

Constructing and Characterising Solar Structure Models for Computational Helioseismology

In this paper, we construct background solar models that are stable against convection, by modifying the vertical pressure gradient of Model S (Christensen-Dalsgaard et al., 1996, Science, 272, 1286) relinquishing hydrostatic equilibrium. However, the stabilisation affects the eigenmodes that we wish to remain as close to Model S as possible. In a bid to recover the Model S eigenmodes, we choose to make additional corrections to the sound speed of Model S before stabilisation. No stabilised model can be perfectly solar-like, so we present three stabilised models with slightly different eigenmodes. The models are appropriate to study the f and p1 to p4 modes with spherical harmonic degrees in the range from 400 to 900. Background model CSM has a modified pressure gradient for stabilisation and has eigenfrequencies within 2% of Model S. Model CSM_A has an additional 10% increase in sound speed in the top 1 Mm resulting in eigenfrequencies within 2% of Model S and eigenfunctions that are, in comparison with CSM, closest to those of Model S. Model CSM_B has a 3% decrease in sound speed in the top 5 Mm resulting in eigenfrequencies within 1% of Model S and eigenfunctions that are only marginally adversely affected. These models are useful to study the interaction of solar waves with embedded three-dimensional heterogeneities, such as convective flows and model sunspots. We have also calculated the response of the stabilised models to excitation by random near-surface sources, using simulations of the propagation of linear waves. We find that the simulated power spectra of wave motion are in good agreement with an observed SOHO/MDI power spectrum. Overall, our convectively stabilised background models provide a good basis for quantitative numerical local helioseismology. The models are available for download from http://www.mps.mpg.de/projects/seismo/NA4/.Comment: 35 pages, 23 figures Changed title Updated Figure 1

Factors associated with quality of services for marginalized groups with mental health problems in 14 European countries

This research was financially supported by DG-Sanco (contract: 800197; 2007-2010). The authors would like to thank all of the professionals and services who participated in the PROMO assessment of services. A PhD grant from Fundação para a Ciência e Tecnologia–Portugal (SFRH/BD/66388/2009) to the first author is acknowledged