Changing nature and sustainability of the industrial district model : the case of Technic Valley in France

This paper examines the impact of contemporary pressures on industrial districts and analyses the changes that are taking place in an industrial district confronted with disembedding and globalization. We discuss the following questions: what are the processes and consequences of disembedding for the changing shape and form of inter-firm trust, contract and network forms? Is there an evolution in subcontracting and trade interdependency? What is the role of institutional infrastructures? We performed a longitudinal qualitative study using a number of different data sources to analyse the evolution of one French industrial district, particularly how new pressures of internationalization and disembedding work to reconfigure inter-firm relations in this district. While the recent literature is dominated by notions about industrial districts that concern only the trend towards increased competition or disembeddedness, this article shows that there is no unilinear trend. In contrast with the findings of certain recent studies, we argue that economic logic does not fully account for recent developments since the adjustment that are being made by the district are characterized rather by re-embeddedness, increased cooperation and institutionalization.industrial district, globalization, economic sociology

Fictitious domain methods for two-phase flow energy balance computations in nuclear components

This paper is dedicated to the numerical simulation of nuclear components (cores and steam generators) by fictitious domain methods. The fictitious domain approach consists in immersing the physical domain under study in a Cartesian domain, called the fictitious domain, and in performing the numerical resolution on this fictitious domain. The calculation times are then efficiently reduced by the use of fast solvers. In counterpart, one has to handle with an immersed boundary, generally non-aligned with the Cartesian mesh, which can be non-trivial. The two fictitious domain methods compared here on industrial simulations and developed by Ramière et al. deal with an approximate immersed interface directly derived from the uniform Cartesian mesh. All the usual immersed boundary conditions (Dirichlet, Robin, Neumann), possibly mixed, are handled through a unique formulation of the fictitious problem. This kind of approximation leads to first-order methods in space that exhibit a good ratio of the precision of the approximate solution over the CPU time, which is very important for industrial simulations. After a brief recall of the fictitious domain method with spread interface (Ramière et al., CMAME 2007) and the fictitious domain method with immersed jumps (Ramière et al., JCP 2008), we will focus on the numerical results provided by these methods applied to the energy balance equation in a steam generator. The advantages and drawbacks of each method will be pointed out. Generally speaking, the two methods confirm their very good efficiency in terms of precision, convergence, and calculation time in an industrial context

FICTITIOUS DOMAIN SIMULATIONS FOR THE TWO-PHASE FLOW ENERGY BALANCE OF THE CLOTAIRE STEAM GENERATOR MOCK-UP

International audienceThe context of this paper is the numerical simulation of a nuclear component, in the framework of the NEPTUNE platform, by a fictitious domain method. We consider industrial simulations of twophase flows with the homogeneous equilibrium (or relaxed) model. The introduction of no remeshing fictitious domain method is mainly motivated by free surface studies, fluid-structure interactions or fast Cartesian mesh solvers. As a first step toward a full fictitious domain simulation, this paper focuses on the fictitious domain computation of the energy balance equation of a nuclear component. Considering the steam generator, this equation is solved by a finite-element volume-penalization method. We recall the model used for the energy balance equation and review the modelizations and the computations. An industrial simulation of the steam generator mock-up CLOTAIRE is presented in order to appreciate the accuracy and the limits of the fictitious domain approach. Exploring L2-norm error along some vertical enthalpy profiles, we claim that the relative error introduced by the fictitious domain method is globally decreasing with the space step and can be lower than 10-3 for space steps around the U-tube diameter size. We conclude that we can reach an enough precision for the industrial applications and benefit from numerical advantages due to the use of Cartesian meshes

Variation in physiological host range in three strains of two species of the entomopathogenic fungus Beauveria

Knowledge of the host range of a biocontrol agent (BCA) is fundamental. Host range determines the BCA's economic potential, as well as the possible risk for non-target organisms. Entomopathogenic fungal strains belonging to the genus Beauveria are widely used as BCA, but our knowledge of their physiological host range is only partial. The aim of this study was to improve our understanding of the physiological host range of three Beauveria strains belonging to two species, B. hoplocheli and B. bassiana. We performed laboratory mortality bioassays to assess their pathogenicity and virulence against nine insect pests, belonging to three orders: Lepidoptera, Coleoptera and Diptera. Mortality rate, mean survival time and mycosis rate were used to estimate virulence. Pathogenicity was assessed as the capacity to cause a disease and induce mortality. Virulence was assessed as the severity of the disease based on mortality rate, mean survival time and mycosis rate. The results of this study revealed significant differences in the physiological host range of the three Beauveria strains tested. The three strains were pathogenic to all Diptera and Lepidoptera species tested. In the case of the Coleoptera, only the B. hoplocheli strain was pathogenic to the white grub Hoplochelus marginalis and only the B. bassiana strains were pathogenic to Alphitobius diaperinus. The B. hoplocheli strain was less virulent on Lepidoptera and Diptera than the two B. bassiana strains. The latter both exhibited very similar virulence patterns. The fact that B. hoplocheli and B. bassiana strains have different host ranges means that they can be used as BCA to target different pests. Impacts on non-target insects across multiple orders cannot be ruled out in the absence of ecological host range studies

Is Dropping out of High School More Likely after Stressful Life Events?

High school dropout is typically viewed as the result of long-held vulnerabilities such as learning problems. This research brief, by PRC visiting scholars Véronique Dupéré and Eric Dion and PRC faculty research associate Robert Crosnoe and colleagues, shows that recent stressful life events can lead to a student dropping out.Population Research Cente

Simplified SIMPs and the LHC

The existence of Dark Matter (DM) in the form of Strongly Interacting Massive Particles (SIMPs) may be motivated by astrophysical observations that challenge the classical Cold DM scenario. Other observations greatly constrain, but do not completely exclude, the SIMP alternative. The signature of SIMPs at the LHC may consist of neutral, hadron-like, trackless jets produced in pairs. We show that the absence of charged content can provide a very efficient tool to suppress dijet backgrounds at the LHC, thus enhancing the sensitivity to a potential SIMP signal. We illustrate this using a simplified SIMP model and present a detailed feasibility study based on simulations, including a dedicated detector response parametrization. We evaluate the expected sensitivity to various signal scenarios and tentatively consider the exclusion limits on the SIMP elastic cross section with nucleons.Comment: 18 pages, 7 figure

Fictitious domain methods to solve convection-diffusion problems with general boundary conditions

International audienceSince a few years, fictitious domain methods have been arising for Computational Fluid Dynamics. The main idea of these methods consists in immersing the original physical domain in a geometrically bigger and simply-shaped other one called fictitious domain. As the spatial discretization is then performed in the fictitious domain, simple structured meshes can be used. The aim of this paper is to solve convection-diffusion problems with fictitious domain methods which can easily simulate free-boundary with possibly deformations of the boundary without increasing the computational cost. Two fictitious domain approaches performing either a spread interface or a thin interface are introduced. These two approaches require neither the modification of the numerical scheme near the immersed interface nor the use of Lagrange multipliers. Several ways to impose general embedded boundary conditions (Dirichlet, Robin or Neumann) are presented. The spread interface approach is computed using a finite element method as a finite volume method is used for the thin interface approach. The numerical schemes conserve the first- order accuracy with respect to the discretization step as observed in the numerical results reported here. The spread interface approach is then combined with a local adaptive mesh refinement algorithm in order to increase the precision in the vicinity of the immersed boundary. The results obtained are full of promise, more especially as convection-diffusion equations are the core of the resolution of Navier-Stokes equations

An ALE-FEM approach to the thermomechanics of solidification processes with application to prediction of pipe shrinkage

International audiencePurpose - The present paper addresses the computer modelling of pipe formation in metal castings. Design/methodology/approach - As a preliminary, a brief review of the current state-of-the-art in pipe shrinkage computation is presented. Then, in first part, the constitutive equations that have to be considered in thermomechanical computations are presented, followed by the main lines of the mechanical finite element resolution. A detailed presentation of an original arbitrary Lagrangian-Eulerian (ALE) formulation is given, explaining the connection between the Lagrangian and the quasi Eulerian zones, and the treatment of free surfaces. Findings - Whereas most existing methods are based on thermal considerations only, it is demonstrated in the current paper that this typical evolution of the free surface, originated by shrinkage at solidification front and compensating feeding liquid flow, can be effectively approached by a thermomechanical finite element analysis. Research limitations/implications - Future work should deal with the following points: identification of thermo-physical and rheological data, automatic and adaptive mesh refinement, calculation of the coupled deformation of mold components, development of a two-phase solid/liquid formulation. Practical implications - An example of industrial application is given. The proposed method has been implemented in the commercial software THERCAST® dedicated to casting simulation. Originality/value - The proposed numerical methods provide a comprehensive approach, capable of modelling concurrently all the main phenomena participating in pipe formation

Terrestrial climate variability and seasonality changes in the Mediterranean region between 15 000 and 4000 years BP deduced from marine pollen records

Pollen-based climate reconstructions were performed on two high-resolution pollen marines cores from the Alboran and Aegean Seas in order to unravel the climatic variability in the coastal settings of the Mediterranean region between 15 000 and 4000 years BP (the Lateglacial, and early to mid-Holocene). The quantitative climate reconstructions for the Alboran and Aegean Sea records focus mainly on the reconstruction of the seasonality changes (temperatures and precipitation), a crucial parameter in the Mediterranean region. This study is based on a multi-method approach comprising 3 methods: the Modern Analogues Technique (MAT), the recent Non-Metric Multidimensional Scaling/Generalized Additive Model method (NMDS/GAM) and Partial Least Squares regression (PLS). The climate signal inferred from this comparative approach confirms that cold and dry conditions prevailed in the Mediterranean region during the Oldest and Younger Dryas periods, while temperate conditions prevailed during the Bølling/Allerød and the Holocene. Our records suggest a West/East gradient of decreasing precipitation across the Mediterranean region during the cooler Late-glacial and early Holocene periods, similar to present-day conditions. Winter precipitation was highest during warm intervals and lowest during cooling phases. Several short-lived cool intervals (i.e. Older Dryas, another oscillation after this one (GI-1c2), Gerzensee/Preboreal Oscillations, 8.2 ka event, Bond events) connected to the North Atlantic climate system are documented in the Alboran and Aegean Sea records indicating that the climate oscillations associated with the successive steps of the deglaciation in the North Atlantic area occurred in both the western and eastern Mediterranean regions. This observation confirms the presence of strong climatic linkages between the North Atlantic and Mediterranean regions