Analyse vibroacoustique de la plaque raidie avec les éléments finis hiérarchiques trigonomériques

Ce mémoire propose une nouvelle aproche pour étudier le comportement acoustique et vibratoire d'une plaque munie de raidisseurs. Les plaques raidies sont à la base de plusieurs structures dans les dommaines naval et aéronautique entre autres. La compréhension des phénomènes vibroacoustiques est essentielle. En effet, les vibrations peuvent causer la fatique et la rupture de composantes. Pour sa part, le bruit est souvent nuisible et il est régi par des lois de plus en plus strictes. Les vibrations ont traditionnellement été étudiées par des éléments finis classiques. Cependant, ces derniers demandent beaucoup de ressources informatiques et ne peuvent simuler que les quelques premiers modes. Pour en améliorer l'efficacité, Bardell[1] a proposé l'utlisation d'éléments finis hiérarchiques pour le calcul des vibrations d'une plaque homogène. Plus tard, Beslin[5] a proposé l'utilisation de fonctions d'interpolation trigonométrique simple comme base aux éléments finis hiérarchiques. Ces fonctions se sont avérées plus stables numériquement et convergement mieux que les éléments de Bardell. Le but de ce mémoire sera d'utiliser les éléments finis hiérarchiques avec les fonctions trigonométriques de Beslin dans le cas d'une plaque finie avec un réseau de raidisseurs. Les plaques utilisées sont rectangulaires et peuvent avoir des conditions limites quelconques. Le modèle de plaque choisi est celui de Love-Kirchhoff qui permet la flexion seulement. Il y aura une description de la méthode d'approximation numérique (Rayleigh-Ritz) et de l'assemblage des éléments de plaque employé. Par la suite, on comparera les performances en termes de modes convergés par rapport aux autres méthodes d'éléments finis. On validera aussi les simulations avec quelques résultats expérimentaux de réponses forcées. Enfin, on utilisera les fonctions trigonométriques pour le calcul de la matrice d'impédance de rayonnement et des indiquateurs vibroacoustiques. Un exemple de plaque entourée d'une baffle rayonnant dans un fluide lourd sera présenté

MetaboAnalyst 5.0: narrowing the gap between raw spectra and functional insights.

Since its first release over a decade ago, the MetaboAnalyst web-based platform has become widely used for comprehensive metabolomics data analysis and interpretation. Here we introduce MetaboAnalyst version 5.0, aiming to narrow the gap from raw data to functional insights for global metabolomics based on high-resolution mass spectrometry (HRMS). Three modules have been developed to help achieve this goal, including: (i) a LC-MS Spectra Processing module which offers an easy-to-use pipeline that can perform automated parameter optimization and resumable analysis to significantly lower the barriers to LC-MS1 spectra processing; (ii) a Functional Analysis module which expands the previous MS Peaks to Pathways module to allow users to intuitively select any peak groups of interest and evaluate their enrichment of potential functions as defined by metabolic pathways and metabolite sets; (iii) a Functional Meta-Analysis module to combine multiple global metabolomics datasets obtained under complementary conditions or from similar studies to arrive at comprehensive functional insights. There are many other new functions including weighted joint-pathway analysis, data-driven network analysis, batch effect correction, merging technical replicates, improved compound name matching, etc. The web interface, graphics and underlying codebase have also been refactored to improve performance and user experience. At the end of an analysis session, users can now easily switch to other compatible modules for a more streamlined data analysis. MetaboAnalyst 5.0 is freely available at https://www.metaboanalyst.ca

L'Abbittibbi et le Témiskaming hier et aujourd'hui

Ouvrage contenant les études suivantes: Benoît-Beaudry Gourd, «La colonisation et le peuplement du Témiscamingue et de l'Abitibi 1880-1950. Aperçu historique». Jean Laflamme, «Un camp de concentration en Abitibi durant la grande guerre». Roger Barrette, «Le plan Vautrin et l'Abitibi-Témiscamingue 1934-1936». Gilbert Saint-Laurent, «Prémices du transport d'écoliers du Québec. L'exemple de la Commission scolaire de Guérin, Comté de Témiscamingue, 1909-1950». Yves Côté, «L'évolution et la régression d'une ville minière: Duparquet». Jacques Meunier, «Réflexion en marge de la marginalité». Laurent Deshaies, «Le développement économique de l'Abitibi-Témiscamingue. Essai de prospective ou esquisse d'une géographie du futur de la région. Première partie». Bibiane Plourde-Savard et Noël Savard, «L'industrie manufacturière du Nord-Ouest québécois». Jean De Denus, «Le conseil régional de développement de l'Abitibi-Témiscamingue. Un organisme-tampon?». Michel Poudrier, «Classes sociales des étudiants du CEGEP du Nord-Ouest.

Detectability of Strange Matter in Heavy Ion Experiments

We discuss the properties of two distinct forms of hypothetical strange matter, small lumps of strange quark matter (strangelets) and of hyperon matter (metastable exotic multihypernuclear objects: MEMOs), with special emphasis on their relevance for present and future heavy ion experiments. The masses of small strangelets up to A = 40 are calculated using the MIT bag model with shell mode filling for various bag parameters. The strangelets are checked for possible strong and weak hadronic decays, also taking into account multiple hadron decays. It is found that strangelets which are stable against strong decay are most likely highly negative charged, contrary to previous findings. Strangelets can be stable against weak hadronic decay but their masses and charges are still rather high. This has serious impact on the present high sensitivity searches in heavy ion experiments at the AGS and CERN facilities. On the other hand, highly charged MEMOs are predicted on the basis of an extended relativistic mean-field model. Those objects could be detected in future experiments searching for short-lived, rare composites. It is demonstrated that future experiments can be sensitive to a much wider variety of strangelets.Comment: 26 pages, 5 figures, uses RevTeX and epsf.st

The changing culture of silviculture

Changing climates are altering the structural and functional components of forest ecosystems at an unprecedented rate. Simultaneously, we are seeing a diversification of public expectations on the broader sustainable use of forest resources beyond timber production. As a result, the science and art of silviculture needs to adapt to these changing realities. In this piece, we argue that silviculturists are gradually shifting from the application of empirically derived silvicultural scenarios to new sets of approaches, methods and practices, a process that calls for broadening our conception of silviculture as a scientific discipline. We propose a holistic view of silviculture revolving around three key themes: observe, anticipate and adapt. In observe, we present how recent advances in remote sensing now enable silviculturists to observe forest structural, compositional and functional attributes in near-real-time, which in turn facilitates the deployment of efficient, targeted silvicultural measures in practice that are adapted to rapidly changing constraints. In anticipate, we highlight the importance of developing state-of-the-art models designed to take into account the effects of changing environmental conditions on forest growth and dynamics. In adapt, we discuss the need to provide spatially explicit guidance for the implementation of adaptive silvicultural actions that are efficient, cost-effective and socially acceptable. We conclude by presenting key steps towards the development of new tools and practical knowledge that will ensure meeting societal demands in rapidly changing environmental conditions. We classify these actions into three main categories: reexamining existing silvicultural trials to identify key stand attributes associated with the resistance and resilience of forests to multiple stressors, developing technological workflows and infrastructures to allow for continuous forest inventory updating frameworks, and implementing bold, innovative silvicultural trials in consultation with the relevant communities where a range of adaptive silvicultural strategies are tested. In this holistic perspective, silviculture can be defined as the science of observing forest condition and anticipating its development to apply tending and regeneration treatments adapted to a multiplicity of desired outcomes in rapidly changing realities

The changing culture of silviculture

Changing climates are altering the structural and functional components of forest ecosystems at an unprecedented rate. Simultaneously, we are seeing a diversification of public expectations on the broader sustainable use of forest resources beyond timber production. As a result, the science and art of silviculture needs to adapt to these changing realities. In this piece, we argue that silviculturists are gradually shifting from the application of empirically derived silvicultural scenarios to new sets of approaches, methods and practices, a process that calls for broadening our conception of silviculture as a scientific discipline. We propose a holistic view of silviculture revolving around three key themes: observe, anticipate and adapt. In observe, we present how recent advances in remote sensing now enable silviculturists to observe forest structural, compositional and functional attributes in near-real-time, which in turn facilitates the deployment of efficient, targeted silvicultural measures in practice that are adapted to rapidly changing constraints. In anticipate, we highlight the importance of developing state-of-the-art models designed to take into account the effects of changing environmental conditions on forest growth and dynamics. In adapt, we discuss the need to provide spatially explicit guidance for the implementation of adaptive silvicultural actions that are efficient, cost-effective and socially acceptable. We conclude by presenting key steps towards the development of new tools and practical knowledge that will ensure meeting societal demands in rapidly changing environmental conditions. We classify these actions into three main categories: re-examining existing silvicultural trials to identify key stand attributes associated with the resistance and resilience of forests to multiple stressors, developing technological workflows and infrastructures to allow for continuous forest inventory updating frameworks, and implementing bold, innovative silvicultural trials in consultation with the relevant communities where a range of adaptive silvicultural strategies are tested. In this holistic perspective, silviculture can be defined as the science of observing forest condition and anticipating its development to apply tending and regeneration treatments adapted to a multiplicity of desired outcomes in rapidly changing realities

Phase transitions in quantum chromodynamics

The current understanding of finite temperature phase transitions in QCD is reviewed. A critical discussion of refined phase transition criteria in numerical lattice simulations and of analytical tools going beyond the mean-field level in effective continuum models for QCD is presented. Theoretical predictions about the order of the transitions are compared with possible experimental manifestations in heavy-ion collisions. Various places in phenomenological descriptions are pointed out, where more reliable data for QCD's equation of state would help in selecting the most realistic scenario among those proposed. Unanswered questions are raised about the relevance of calculations which assume thermodynamic equilibrium. Promising new approaches to implement nonequilibrium aspects in the thermodynamics of heavy-ion collisions are described.Comment: 156 pages, RevTex. Tables II,VIII,IX and Fig.s 1-38 are not included as postscript files. I would like to ask the requestors to copy the missing tables and figures from the corresponding journal-referenc

Analyse vibroacoustique de la plaque raidie avec les éléments finis hiérarchiques trigonomériques

Ce mémoire propose une nouvelle aproche pour étudier le comportement acoustique et vibratoire d'une plaque munie de raidisseurs. Les plaques raidies sont à la base de plusieurs structures dans les dommaines naval et aéronautique entre autres. La compréhension des phénomènes vibroacoustiques est essentielle. En effet, les vibrations peuvent causer la fatique et la rupture de composantes. Pour sa part, le bruit est souvent nuisible et il est régi par des lois de plus en plus strictes. Les vibrations ont traditionnellement été étudiées par des éléments finis classiques. Cependant, ces derniers demandent beaucoup de ressources informatiques et ne peuvent simuler que les quelques premiers modes. Pour en améliorer l'efficacité, Bardell[1] a proposé l'utlisation d'éléments finis hiérarchiques pour le calcul des vibrations d'une plaque homogène. Plus tard, Beslin[5] a proposé l'utilisation de fonctions d'interpolation trigonométrique simple comme base aux éléments finis hiérarchiques. Ces fonctions se sont avérées plus stables numériquement et convergement mieux que les éléments de Bardell. Le but de ce mémoire sera d'utiliser les éléments finis hiérarchiques avec les fonctions trigonométriques de Beslin dans le cas d'une plaque finie avec un réseau de raidisseurs. Les plaques utilisées sont rectangulaires et peuvent avoir des conditions limites quelconques. Le modèle de plaque choisi est celui de Love-Kirchhoff qui permet la flexion seulement. Il y aura une description de la méthode d'approximation numérique (Rayleigh-Ritz) et de l'assemblage des éléments de plaque employé. Par la suite, on comparera les performances en termes de modes convergés par rapport aux autres méthodes d'éléments finis. On validera aussi les simulations avec quelques résultats expérimentaux de réponses forcées. Enfin, on utilisera les fonctions trigonométriques pour le calcul de la matrice d'impédance de rayonnement et des indiquateurs vibroacoustiques. Un exemple de plaque entourée d'une baffle rayonnant dans un fluide lourd sera présenté