Knowledge Based Cloud FE simulation – data-driven material characterization guidelines for the hot stamping of aluminium alloys

The Knowledge Based Cloud FEA (KBC-FEA) simulation technique allows multi-objective FE simulations to be conducted on a cloud-computing environment, which effectively reduces computation time and expands the capability of FE simulation software. In this paper, a novel functional module was developed for the data mining of experimentally verified FE simulation results for metal forming processes obtained from KBC-FE. Through this functional module, the thermo-mechanical characteristics of a metal forming process were deduced, enabling a systematic and data-driven guideline for mechanical property characterization to be developed, which will directly guide the material tests for a metal forming process towards the most efficient and effective scheme. Successful application of this data-driven guideline would reduce the efforts for material characterization, leading to the development of more accurate material models, which in turn enhance the accuracy of FE simulations

Anthropogenic features in the Sines (Portugal) and Essaouira (Morocco) coastal aquifers: a comparative study of their hydrochemical evolution by a Principal Component Analysis.

Considering the effects of climatic conditions on groundwater resources salinization and quality, a comparative study was conducted on the coastal aquifers of Sines (Portugal) and Essaouira (Morocco). Under the climatic and environmental conditions these two basins present different vulnerabilities to anthropogenic activities. Both aquifers correspond to sedimentary basins with similar structures and lithologies. From the available physical, chemical and piezometric data, two series of results of each area were selected corresponding to two different years that were analysed by Principal Component Analysis (PCA). Sines basin is characterised by a temperate climate. In the Sines aquifer the waterrock interaction process is the major mechanism responsible for the groundwater evolution, conferring a calcium-bicarbonate facies. Applying the PCA, punctual anthropogenic contamination was identified and linked to agricultural activities. The water resources of the Essaouira basin are characteristic of a semi-arid climate, and are severely impacted by the climate (quantity and quality). PCA allowed the evaluation of the contribution of the Tidzi diapir in the water recharge that confers to the groundwater a sodium-chloride facies. Although this statistical method did not shown a nitrate contamination input in the Essaouira multi-aquifer, this polluent presents locally high values. Also the very high evaporation and scarce precipitation activate the processes of salinization and contamination.Considerando los efectos de las condiciones climáticas sobre la calidad y la salinidad de las aguas subterráneas, se ha llevado a cabo un estudio comparativo entre los acuíferos costeros de Sines (Portugal) y de Essaouira (Marruecos). Teniendo en cuenta las condiciones climáticas y el medio ambiente de estas dos cuencas, resultan distintas vulnerabilidades a las actividades antrópicas. Ambos acuíferos se localizan en cuencas sedimentarias de estructura y de litología idénticas. Un Análisis de Componentes Principales fue realizado a partir de datos físicos, químicos y piezométricos conseguidos durante dos años en cada área. La cuenca de Sines se caracteriza por un clima templado. En el acuífero de Sines el desarrollo de las interacciones agua-roca es mayoritariamente responsable de la modificación de las aguas subterráneas, confiriendo una facies calcio-bicarbonatada. Mediante un Análisis de Componentes Principales, se identificó una contaminación antropogénica puntual de origen agrícola. Los recursos en agua de la cuenca de Essaouira están dentro de un clima semiárido, dependiendo muchísimo de este (cantidad y calidad). La utilización de la citada metodología permitió evidenciar la contribución del diapiro Tidzi en las aguas de recargas, confiriendo una facies de cloruro sódico en las aguas subterráneas. Aunque este método estadístico no permitió la demostración de la contaminación por los nitratos en los diversos acuíferos de Essaouira, aquel contaminante se encontraba puntualmente en altas concentraciones. Por otra parte, la fuerte evaporación y las bajas precipitaciones amplían el fenómeno de salinidad y de contaminación

Dynamical Dark Energy and Spontaneously Generated Gravity

We study the cosmological evolution of an induced gravity model with a scale symmetry breaking potential for the scalar field. The radiation to matter transition, following inflation and reheating, influences the dynamics of such a field through its non minimal coupling. We illustrate how, under certain conditions on the potential, such a dynamics can lead to a suitable amount of dark energy explaining the present accelerated expansion.Comment: 14 pages, 3 figure

Non-chaotic dynamics in general-relativistic and scalar-tensor cosmology

In the context of scalar-tensor models of dark energy and inflation, the dynamics of vacuum scalar-tensor cosmology are analysed without specifying the coupling function or the scalar field potential. A conformal transformation to the Einstein frame is used and the dynamics of general relativity with a minimally coupled scalar field are derived for a generic potential. It is shown that the dynamics are non-chaotic, thus settling an existing debate.Comment: 20 pages, LaTeX, to appear in Class. Quantum Gra

Origine et datation des eaux souterraines du bassin hydrologique de la lagune d’Oualidia

Le Sahel d’Oualidia fait partie du littoral atlantique. Il borde la lagune d’Oualidia, avec un climat dominant de type semi-aride. Dans cette zone, les aquifères carbonatés de grès calcaire plio-quaternaire et du calcaire de Dridrate (Hauterivien supérieur), sont en relation directe avec l’océan atlantique. Ces aquifères subissent des prélèvements par pompage destinés à l’irrigation de cultures maraîchères et à l’alimentation de la population rurale. Par conséquent, ils sont menacés par des problèmes de surexploitation et de salinisation par intrusion marine. De nombreuses questions sont actuellement posées sur l’importance des ressources souterraines exploitées et sur leur état de salinité. Dans le cadre de cette étude, l’utilisation des isotopes stables 18O et 2H, a permis de mettre en évidence la recharge des aquifères qui se fait par des pluies d’origine atlantique. Les eaux souterraines sont localement affectées par des intrusions d’eau océanique. La datation de certains échantillons par le 14C a permis de révéler des âges anciens. D’autres analyses seront réalisées pour vérifier ces hypothèses.El Sahel de Oualidia se encuentra en el litoral atlántico. Está en el borde de la laguna de Oualidia con un clima predominantemente de tipo semi-árido. En esta zona, los acuíferos carbonatados de las areniscas calcáreas plio-cuaternarias y de la caliza de Dridrate (Hauteriviense superior) están relacionados directamente con el Océano Atlántico. Estos acuíferos están sometidos a descarga por bombeos utilizados para el riego de los cultivos de las marismas y para el abastecimiento de la población rural. Por ello, están amenazados por problemas de sobreexplotación y de salinización por intrusión marina. Se plantean actualmente numerosas cuestiones sobre la importancia de los recursos subterráneos explotados y sobre su estado de salinización. Dentro del marco de este estudio, la utilización de isótopos estables de 18O y 2H permite poner en evidencia la recarga de los acuíferos que se efectúa por las lluvias de origen atlántico. Las aguas subterráneas se ven localmente afectadas por intrusiones de agua oceánica. La datación de algunas muestras por el 14C demuestra la existencia de edades antiguas. Se realizarán otros análisis para verificar estas hipótesis

THE HIGGS-YUKAWA MODEL IN CURVED SPACETIME

The Higgs-Yukawa model in curved spacetime (renormalizable in the usual sense) is considered near the critical point, employing the $1/N$--expansion and renormalization group techniques. By making use of the equivalence of this model with the standard NJL model, the effective potential in the linear curvature approach is calculated and the dynamically generated fermionic mass is found. A numerical study of chiral symmetry breaking by curvature effects is presented.Comment: LaTeX, 9 pages, 1 uu-figur

Inflation and quintessence with nonminimal coupling

The nonminimal coupling (NMC) of the scalar field to the Ricci curvature is unavoidable in many cosmological scenarios. Inflation and quintessence models based on nonminimally coupled scalar fields are studied, with particular attention to the balance between the scalar potential and the NMC term in the action. NMC makes acceleration of the universe harder to achieve for the usual potentials, but it is beneficial in obtaining cosmic acceleration with unusual potentials. The slow-roll approximation with NMC, conformal transformation techniques, and other aspects of the physics of NMC are clarified.Comment: 36 pages, LaTeX. Typos in Eq. (2.5) correcte

Can induced gravity isotropize Bianchi I, V, or IX Universes?

We analyze if Bianchi I, V, and IX models in the Induced Gravity (IG) theory can evolve to a Friedmann--Roberson--Walker (FRW) expansion due to the non--minimal coupling of gravity and the scalar field. The analytical results that we found for the Brans-Dicke (BD) theory are now applied to the IG theory which has $\omega \ll 1$ ($\omega$ being the square ratio of the Higgs to Planck mass) in a cosmological era in which the IG--potential is not significant. We find that the isotropization mechanism crucially depends on the value of $\omega$. Its smallness also permits inflationary solutions. For the Bianch V model inflation due to the Higgs potential takes place afterwads, and subsequently the spontaneous symmetry breaking (SSB) ends with an effective FRW evolution. The ordinary tests of successful cosmology are well satisfied.Comment: 24 pages, 5 figures, to be published in Phys. Rev. D1