Phase-space methods in nuclear reactions around the Fermi energy

Some prescriptions for in-medium complex particle production in nuclear reactions are proposed. They have been implemented in two models to simulate nucleon-nucleus (nIPSE) and nucleus-nucleus (HIPSE) reactions around the Fermi energy \cite{Lac04,Lac05}. Our work emphasizes the effect of randomness in cluster formation, the importance of the nucleonic Fermi motion as well as the role of conservation laws. The key role of the phase-space exploration before and after secondary decay is underlined. This is illustrated in the case of two debated issues: the memory loss of the entrance channel in central collisions and the $(N,Z)$ partitions after the pre-equilibrium stage.Comment: Proceedings of the IWM2005 workshop, Catane (Italy), Nov. 2005. DOWNLOAD HIPSE program at: http://caeinfo.in2p3.fr/theorie/theory_lacroix.htm

Diseño de un sistema logístico para una pequeña empresa comercializadora de ferretería

La presente tesis se ubica en el contexto de operación y administración logística para una pequeña empresa, enfocándola desde un punto de vista sistémico, con gran exigencia de coordinación de todas las funciones logísticas. La tesis tiene como objetivo general, el diseñar un modelo de sistema logístico para una pequeña empresa comercializadora, con el fin de optimizar las operaciones, minimizar costos y agilizar entregas de pedidos, de tal manera que la empresa pueda tener un crecimiento sostenido aceptable, a través de la utilización eficiente de recursos. Para esto, se muestra, como primer paso esencial, la metodología para el diseño y planificación del sistema logístico; diseño realizado en forma global y para cada una de las funciones logísticas (distribución y servicios, almacenamiento, compras y planificación y control de inventarios). Esta tesis tiene cinco objetivos específicos: primero, estudiar un caso real haciendo un diagnóstico y propuesta de un sistema logístico en una pequeña empresa comercializadora, mostrando la importancia de éste en dicha empresa; segundo, establecer cómo debe ser la gestión de inventarios en una empresa que presenta existencias de gran variedad y alto volumen; tercero, especificar los cálculos mínimos necesarios de logística operacional referidos a una pequeña empresa; cuarto, realizar un diseño organizacional del departamento de logística para una pequeña empresa, y quinto, mostrar el funcionamiento del Just In Time en la logística de una pequeña empresa. El logro de estos objetivos se da, inicialmente, con la presentación del marco teórico relacionado a la logística, aplicable a una pequeña empresa, tal que permita realizar una reingeniería sobre el proceso administrativo y operacional actual. Luego, se realiza un estudio de caso, que involucra la descripción, el análisis y diagnóstico del sistema logístico actual, así como propuestas de un sistema logístico que permita mejorar el desempeño y de esta forma disminuir costos. Por último, se presentan las conclusiones que muestran los aspectos más relevantes, encontrados durante la investigación.Tesi

Les parcs scientifiques du Québec : la perspective des entreprises : rapport de recherche

RÉSUMÉ: Cette recherche, financée par la Ville de Lévis, vise à avancer les connaissances sur les facteurs de succès des entreprises établies dans un parc scientifique. Afin de bien comprendre ces facteurs de succès, 12 entrevues semi-dirigées ont été menées entre septembre 2016 et avril 2017 auprès d’entreprises, d’organismes gouvernementaux et d’acteurs du milieu académique établis dans les parcs scientifiques du Québec, au Canada. Une approche exploratoire a été adoptée afin de réaliser cette recherche. En effet, une démarche inductive permet de mieux comprendre un phénomène, tel que la dynamique d’un parc scientifique. Les résultats présentés dans ce document traitent premièrement des diverses définitions du concept de parc scientifique ainsi que du portrait des parcs scientifiques au Québec. Les motivations des entreprises à s’établir dans un parc scientifique, leurs attentes face à leur parc scientifique ainsi que les incitatifs mis en place par les parcs seront ensuite présentés. Les résultats des entrevues ont permis d’identifier les effets des parcs scientifiques sur chacune des phases du processus d’innovation (Tiwari, 2007) : conception, développement et marketing. L’analyse de ces résultats permettra finalement d’identifier les facteurs de succès des entreprises établies dans les parcs scientifiques. Bref, les résultats de cette recherche permettent de fournir des pistes de réflexion pour la gestion des parcs scientifiques ainsi que pour les entreprises qui souhaitent s’établir dans un parc scientifique. -- ABSTRACT: This research, funded by the City of Lévis, aims to advance knowledge on the success factors of businesses established in a science park. In order to fully understand these success factors, 12 semi-structured interviews were conducted between September 2016 and April 2017 with businesses, government agencies and academic stakeholders in science parks in the province of Québec, Canada. An exploratory approach was adopted to carry out this research. Indeed, an inductive approach allows a better understanding of a phenomenon, such as the dynamics of a science park. The results presented in this document firstly deal with the various definitions of the concept of a science park as well as the portrait of the science parks in the province of Québec. The motivations of businesses to establish themselves in a science park, their expectations of their science park and the incentives proposed by the parks will be presented. The results of the interviews identified the effects that the science parks have on each phase of the innovation process (Tiwari, 2007): conception, implementation and marketing. The analysis of these results will ultimately identify the success factors of businesses established in science parks. In short, the results of this research help to provide insights for the management of science parks as well as for businesses wishing to establish themselves in a science park

Computational elastoacoustics of uncertain complex systems and experimental validation

Semi-Plenary LectureInternational audienceThe paper deals with the robustness of uncertain computational elastoacoustic models in low- and medium-frequency ranges. The elastoacoustic system is made up of a heterogeneous viscoelastic structure coupled with an internal acoustic cavity filled with a dissipative acoustic fluid. A reduced mean elastoacoustic model is deduced from the mean finite element model by using the modal approach with the structural modes of the structure and the acoustic modes of the acoustic cavity. Data uncertainties and model uncertainties are taken into account by using a nonparametric probabilistic approach for the structure, for the acoustic cavity and for the vibroacoustic coupling interface. The main objectives of this paper are (1) to present experimental validation of the nonparametric probabilistic approach of model uncertainties and to propose methods to perform the experimental identification of the probabilistic model parameters, (2) to analyze the robustness of computational elastoacoustic models with respect to model and data uncertainties, (3) to study uncertainty propagation through complex elastoacoustic systems. Two experimental configurations are analyzed with the stochastic computational elastoacoustic model. The first experimental configuration is made up of a composite sandwich panel coupled with an acoustic cavity constituted of a simple rigid box. Experimental measurements have been performed for 8 manufactured composite panels. The second experimental configuration is a car made up of a complex heterogeneous structure coupled with a complex acoustic cavity. Experimental measurements have been performed for 22 manufactured cars of the same type with optional extra

Silicon on Nothing Mems Electromechanical Resonator

The very significant growth of the wireless communication industry has spawned tremendous interest in the development of high performances radio frequencies (RF) components. Micro Electro Mechanical Systems (MEMS) are good candidates to allow reconfigurable RF functions such as filters, oscillators or antennas. This paper will focus on the MEMS electromechanical resonators which show interesting performances to replace SAW filters or quartz reference oscillators, allowing smaller integrated functions with lower power consumption. The resonant frequency depends on the material properties, such as Young's modulus and density, and on the movable mechanical structure dimensions (beam length defined by photolithography). Thus, it is possible to obtain multi frequencies resonators on a wafer. The resonator performance (frequency, quality factor) strongly depends on the environment, like moisture or pressure, which imply the need for a vacuum package. This paper will present first resonator mechanisms and mechanical behaviors followed by state of the art descriptions with applications and specifications overview. Then MEMS resonator developments at STMicroelectronics including FEM analysis, technological developments and characterization are detailed.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Standing variation and new mutations both contribute to a fast response to selection for flowering time in maize inbreds

<p>Abstract</p> <p>Background</p> <p>In order to investigate the rate and limits of the response to selection from highly inbred genetic material and evaluate the respective contribution of standing variation and new mutations, we conducted a divergent selection experiment from maize inbred lines in open-field conditions during 7 years. Two maize commercial seed lots considered as inbred lines, <it>F</it>252 and <it>MBS</it>847, constituted two biological replicates of the experiment. In each replicate, we derived an Early and a Late population by selecting and selfing the earliest and the latest individuals, respectively, to produce the next generation.</p> <p>Results</p> <p>All populations, except the Early <it>MBS</it>847, responded to selection despite a short number of generations and a small effective population size. Part of the response can be attributed to standing genetic variation in the initial seed lot. Indeed, we identified one polymorphism initially segregating in the <it>F</it>252 seed lot at a candidate locus for flowering time, which explained 35% of the trait variation within the Late <it>F</it>252 population. However, the model that best explained our data takes into account both residual polymorphism in the initial seed lots and a constant input of heritable genetic variation by new (epi)mutations. Under this model, values of mutational heritability range from 0.013 to 0.025, and stand as an upper bound compare to what is reported in other species.</p> <p>Conclusions</p> <p>Our study reports a long-term divergent selection experiment for a complex trait, flowering time, conducted on maize in open-field conditions. Starting from a highly inbred material, we created within a few generations populations that strikingly differ from the initial seed lot for flowering time while preserving most of the phenotypic characteristics of the initial inbred. Such material is unique for studying the dynamics of the response to selection and its determinants. In addition to the fixation of a standing beneficial mutation associated with a large phenotypic effect, a constant input of genetic variance by new mutations has likely contributed to the response. We discuss our results in the context of the evolution and mutational dynamics of populations characterized by a small effective population size.</p