Speciale: Il terremoto ligure del 23 Febbraio del 1887

L'educazione e la formazione sono due ingredienti che consentono ai cittadini di apprendere le informazioni scientifiche altrimenti confinate nei laboratori in particolare nel campo del rischio ambientale. E in questa ottica che è nato il programma O3E (acronimo in francese di Osservazione dell'Ambiente a scopo Educativo per le Scuole). II programma O3E fa seguito a un periodo di sperimentazione di 10 anni (1997-2007) in cui sono nati diversi progetti nazionali (Sismos a l'Ecole, EDURISK, climAtscope). L'obiettivo generale del programma O3E è mettere in rete istituti scolastici nelle regioni delle Alpi latine equipaggiate con sensori di parametri ambientali di tipo educativo. I dati sul movimento del suolo (sismometri), sulle temperature e la pluviometria (stazioni meteo), sulle risorse idriche (idrogeologia) registrati negli istituti scolastici sono raccolti su server dedicati poi messi a disposizione attraverso Internet alla comunità educativa. La rete O3E così strutturata, diventa il punto di partenza per varie attività di insegnamento delle geoscienze e di educazione al rischio naturale e si propone di: - promuovere le scienze sperimentali e le nuove tecnologie - mettere in rete gli attori dell'educazione e della formazione - sviluppare il senso di autonomia e la responsabilità dei giovani - rafforzare e sviluppare i legami con i partner regionali nel campo educativo e universitario - favorire una presa di coscienza razionale dei problemi legati alla prevenzione dei rischi naturali e del patrimonio geologico, ciò che può fare la differenza durante un evento in termini di sicurezza. Tenendo conto degli orientamenti del programma, che dà un grande spazio alle tecnologie di comunicazione, della sua dimensione educativa (sensibilizzazione ai rischi ambientali), del suo contenuto scientifico (geoscienze), e della sua importanza su scala regionale e persino internazionale (messa in rete di istituti scolastici), vengono avviate iniziative da parte degli istituti scolastici in stretta collaborazione con il mondo dell'Università e della Ricerca. E' il caso del presente opuscolo che tratta il caso di un terremoto emblematico per le regioni interessate da O3E: il terremoto di Imperia - Mentone del 23 febbraio 1887. I dati raccolti qui (archivi, sismogrammi, ultimi studi oceanografici. .. ) consentiranno agli studenti e ai loro insegnanti di affrontare un caso di studio.CG06, Region PACA, DIREN PACA, Sciences a l'Ecole; ALCOTRAPublished5.9. Formazione e informazioneope

Earthquakes, The hows and whys. Focus on The February 23, 1887 Ligurian earthquake

Education and training are two ingredients that allow citizens to learn scientific information otherwise confined within laboratories, in particular in the field of environmental risk. It is in this perspective that the O3E (French acronym for European Observatory for Education and Environment) project was born. The O3E project is the follow up of a 10 year long testing phase (1997-2007) during which several national projects ("Sismos a I'Ecole", "EDURISK" and "climAtscope") were born. The overall objective of the O3E program is to network educational institutions, which are equipped with educational instruments and sensors to measure environmental parameters, across regions of the Latin Alps. Data on ground motion (seismometers), temperatures and rainfall (weather stations), on water resources (hydrogeology) recorded in schools are collected on dedicated servers, which are then made available to the educational community through the Internet. The so-structured O3E network becomes the starting point for many geosciences teaching and educational activities to natural hazards in order to: - promote experimental sciences and new technologies - network the actors involved in education and training - develope the sense of autonomy and responsibility in young people - strenghten and develope relations with regional partners in the field of education and academia - foster rational awareness of the problems related to the geological heritage and to the prevention of natural hazards, that is what can make the difference, in terms of safety, when an event occurs. Taking into account the guidelines of the program (which gives a large space to communication technologies), its educational dimension (awareness of environmental risks), its scientific content (geosciences), and its importance on a regional and even international scale (networking of schools), initiatives are started up by schools in close cooperation with the university and research community. As it is the case of this pamphlet dealing with an earthquake, which is emblematic for the regions involved in the O3E project: the Imperia -Menton earthquake occurred on February 23,1887. The data collected here (archives, seismograms, recent oceanographic studies ... ) will enable students and their teachers to deal with a case study.CG 06, Région PACA, DIREN PACA, Sciences à l'Ecole; Alcotra, EUPublished5.9. Formazione e informazioneope

The participation of the works council in the economic decisions of the company

Le comité d’entreprise, devenu comité social et économique, participe aux décisions économiques de l’entreprise. Cette participation emprunte, pour l’essentiel, deux formes : l’information-consultation et la négociation. L’information-consultation est la forme la plus ancienne ; sa dynamique est désormais stabilisée. Procédant d’un incrémentalisme désordonné, l’information-consultation du comité social et économique sur les décisions de l’employeur est critiquable. Elle n’a pas pour objet de lier ce dernier. Les sanctions de la méconnaissance de l’obligation d’information-consultation du comité social et économique ne sont pas non plus de nature à assurer l’effectivité de cette forme de participation. L’essor de la négociation comme vecteur de participation du comité social et économique pourrait résoudre ces difficultés. La négociation transforme son rôle dans l’entreprise. Au terme d’évolutions multiples, le comité social et économique devient progressivement co-titulaire du pouvoir décisionnel dans l’entreprise, en étant l’interlocuteur privilégié de l’employeur dans la négociation. Il intervient pour organiser les conditions de sa participation dans l’entreprise, et pour pallier l’absence de négociateur syndical. Cette accession nouvelle du comité social et économique au pouvoir décisionnel de l’entreprise trouve son point d’orgue dans la possibilité offerte aux partenaires sociaux de décider sa transformation en conseil d’entreprise. Ce dernier est seul habilité à négocier avec l’employeur. Cette transformation marque une évolution capitale de sa participation aux décisions économiques de l’entreprise.The works council, which has become the social and economic committee, participates in the economic decisions of the company. This participation takes two main forms: information-consultation and negotiation. Information-consultation is the oldest form; its dynamic is now stabilized. Proceeding from a disordered incrementalism, the information-consultation of the social and economic committee on the decisions of the employer is open to criticism. Its purpose is not to bind the latter. The sanctions of the disregard of the obligation of information-consultation of the social and economic committee are not likely to ensure the effectiveness of this form of participation either. The development of negotiation as a means of participation of the social and economic committee could resolve these difficulties. Negotiation transforms its role in the company. Following a number of developments, the social and economic committee is gradually becoming the joint holder of decision-making power in the company, by being the employer's preferred negotiating partner. It intervenes to organize the conditions of its participation in the company, and to compensate for the absence of a trade union negotiator. This new accession of the social and economic committee to the decision-making power of the company culminates in the possibility offered to the social partners to decide its transformation into a company council. The latter has the sole right to negotiate with the employer. This transformation marks a major evolution in its participation in the economic decisions of the company

Is the Penman-Monteith model adapted to predict crop transpiration under greenhouse conditions? Application to a New Guinea Impatiens crop

International audienceReducing water consumption in greenhouses is one of the main concerns for growers. This implies better knowledge of the transpiration process in order to adapt water inputs to plant needs. Several simple models have been developed to estimate transpiration. The Penman-Monteith (PM) model and the Direct Method (DM) model are two of the most widespread transpiration models. Yet the PM model was primarily developed for crops grown in open field conditions; its validity in the case of sheltered crops is only seldom questioned. Moreover, the PM model is rarely compared to the DM model, although this could be a simple way to quantify its performance. The aim of the study is thus, first, to analyse the ability of the classical PM model to assess the transpiration rate inside a greenhouse with a New Guinea Impatiens crop in order to identify which modifications should be introduced to improve its efficiency. Comparison of the PM model with measurements reveals severe discrepancies. A detailed assessment of the assumptions underlying the PM model revealed that the location of the climatic parameters used to implement the model is a key factor that affects the results. The present study demonstrates that the temperature and humidity considered in the PM model should be taken inside the crop and not above the crop, leading to a so-called PM-Like (PML) model. Results show that the PM-Like and the DM models, in a one-layer configuration, give similar results and are in agreement with actual measurements. The capacity of the PM-Like and the DM models to investigate the vertical distribution of the transpiration inside the crop is also discussed. After dividing the canopy into two layers, the PML and DM models were applied and validated against experimental data. Even if such a procedure does not really improve the quality of the results compared to the one-layer models, it provides innovative information on the vertical distribution of the transpiration, which could have applications in CFD modelling

CFD prediction of the daytime climate evolution inside a greenhouse taking account of the crop interaction, sun path and ground conduction

International audienceThe management of the local climate inside a greenhouse is essential to control the plant growth and reach the expected quality level for commercialization. In recent years, Computational Fluid Dynamics (CFD) proved to be an efficient tool to predict the greenhouse climate and therefore could serve as decision-making tool in the next future. Nevertheless, up until now, very few studies included together the sun path, plant interaction with local environment, and ground inertia effects. In addition, validation was generally based on only one or two parameters. The present study aims at analysing the evolution of the climate inside a greenhouse using CFD and taking account of the main heat and mass transfer processes at a daily time scale. A particular attention was paid to the validation of the model, considering air temperature and humidity inside and above the crop, as well as leaf temperature, crop transpiration and ground temperature. The CFD model solved the Reynolds Averaged Navier-Stokes equations, using a k-ε closure for turbulence. Specific submodels were established to include the sun path as well as the crop interaction with the local climate. The ground was also meshed to assess its inertia effects. 2D unsteady simulations were launched, considering only cases for which the wind blew perpendicular to the ridge. The validation of the model was undertaken on the basis of experiments conducted for a 100 m2 Venlo-greenhouse with Impatiens pot plants grown on shelves. A typical sunny day of spring in Angers, France, was retained. The model showed its ability to correctly predict the temperature and humidity dynamics inside the greenhouse as well as the leaf temperature and crop transpiration evolutions. Although slight discrepancies were observed for the air temperature and humidity inside the crop, the main trends were correctly predicted

Analysis of the time evolution of the intercepted radiation inside a crop using CFD

Times Cited: 0;International Symposium on New Technologies for Environment Control, Energy-Saving and Crop Production in Greenhouse and Plant Factory - Greensys 2013, Jeju, Korea Republic, 22-27 September 2013.International audienceAssessing the distribution of short wavelength radiation inside a greenhouse crop is of prime interest as absorbed radiation is one of the main factors governing the energy and water vapour transfers at plant level. The aim of this paper is to analyse the distribution of solar radiation inside an ornamental crop and to improve the crop submodel implemented in CFD tools. In this prospect, a glasshouse compartment was equipped with a set of five silicon solar cells equally distributed vertically inside a New Guinea Impatiens potted crop. Fitting the data with the exponential Beer's law made it possible the determination of the corresponding extinction coefficient. A CFD model was then used to predict the solar radiation distribution inside the canopy all day long. Contrary to the commonly adopted technique which consists in describing the vertical exponential decay of the radiation from the knowledge of the incident solar radiation, the model solves the radiative transfer equation with the Discrete Ordinates model. The model requires the definition of the absorption coefficient which is inferred from the measured extinction coefficient. The model was first validated comparing the vertical distribution of solar radiation to the measured one at midday. It showed its ability to predict the exponential decay of the shortwave radiation and evidenced the variation of the diurnal vertical extinction coefficient all day long. Dividing the crop into five horizontal layers, the model was then applied to assess the evolution and proportion of the absorbed radiation in each layer. It was shown that the relative proportion of radiation absorbed in the upper layer varied all day long, reaching its minimum at midday

Étude de la pulvérisation et de l'émission de la matière sous bombardement Cs+

La technique Storing Matter a pour objectif d améliorer la sensibilité et la quantification des analyses par SIMS. Elle consiste à découpler la phase de pulvérisation de l échantillon de la phase d analyse. Pour cela, la matière pulvérisée par bombardement ionique est déposée en sous-monocouche sur un collecteur optimisé. Le dépôt est ensuite analysé par SIMS. La probabilité d ionisation de la matière ne dépend plus de son environnement initial ( effet de matrice ), mais de la surface du collecteur. Le choix du collecteur permet un gain de sensibilité et la quantification des concentrations de l échantillon initial. L efficacité de la technique dépend du choix du collecteur et d un facteur de collection ? caractérisant la phase de pulvérisation-dépôt. Dans ce travail, nous avons étudié la pulvérisation et l émission de la matière sous bombardement ionique pour optimiser ce facteur ?. Nous avons mis au point un dispositif expérimental ainsi qu un protocole d analyse par SIMS qui nous a permis d étudier la distribution angulaire sous un bombardement d ions Cs+ avec une incidence oblique pour différents paramètres d impact. L étude menée sur quatre cibles (Si, Ge, InP et GaAs) a montré que la distribution angulaire est de forme cosn (?-?Max) pour une énergie et un angle d impact de respectivement 2 à 10 keV et 30 à 60. L exposant n est ~2 tandis que la direction d émission préférentielle ?Max varie de la normale à la surface (0) jusqu à un angle d émission de 35 dans la direction spéculaire au faisceau en fonction de l énergie d impact et de l angle d incidence. Ces résultats appliqués à Storing Matter ont permis de déterminer la configuration optimum pour une collection maîtrisée en fonction du bombardementThe Storing Matter technique aims at optimising the sensitivity and quantitativeness of SIMS analysis. It consists in decoupling the sputtering of the specimen from the subsequent analysis step. The specimen is sputtered by means of an ion beam. The emitted particles are deposited at a sub-monolayer level on an optimised collector. The deposit is subsequently analysed in a SIMS instrument. The ionisation probability in SIMS does not depend anymore on the initial sample composition ( Matrix effect ), but on the collector surface chemistry. The collector is chosen in order to increase the sensitivity and to quantify the specimen. The efficiency of this new technique depends on the collector choice and on the collection factor ? characterising the sputter-deposition step. In this work, the sputtering and emission processes under ionic bombardment have been studied in order to optimise this factor ?. We developed an experimental set-up and an analysis protocol based on SIMS that allows us to study the angular distribution under Cs+ bombardment with an oblique incidence for different impact parameters. Four targets (Si, Ge, InP and GaAs) were studied. The results show that the angular distribution is shaped as a cosine function cosn (?-?Max) for impact energies between 2 and 10 keV and for incidence angles from 30 to 60. Under these conditions, the exponent n is ~2 and the preferential direction of emission ?Max varies from the normal to the surface to 35 in the specular direction in function of the impact energy and the incidence angle. The results allowed to find the best settings for the Storing Matter technique to control the sputtered matter collection in function of the bombardment parametersNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

A dehumidification strategy to avoid condensation on plants and spare energy in greenhouse

Times Cited: 0;International Symposium on New Technologies for Environment Control, Energy-Saving and Crop Production in Greenhouse and Plant Factory - Greensys 2013, Jeju, Korea Republic, 22-27 September 2013.International audienceThe increase of fossil energy costs in the past years led producers to use more and more airtight greenhouses (air-inflated double-layer greenhouse) to reduce heat loss. Limiting air renewal however induces higher air moisture content and risks of condensation. Under such conditions, which may enhance fungal development (e.g., Botrytis), growing moisture-sensitive ornamental species may become tedious or even impossible (e.g., for cyclamen). Dehumidification may be undertaken through ventilation-heating which is however energy consuming and limits the benefits of modern greenhouses. In order to reduce energy costs, a dehumidification heat pump was set up inside a 2,350 m 2 plastic production greenhouse near Angers (West of France) to extract excess water vapour content from the inside air. This device was mainly used as a curative tool to avoid condensation according to the water vapour pressure deficit evolution. It was designed in such a way to compensate night plant transpiration and its power was only 4 W.m -2 to prevent dew point during the night. During the experiment, it was checked that no condensation occurred on the plants. Moreover, results revealed that the experimental thermodynamic and dehumidification efficiencies were high, and in agreement with values predicted by a simple model. The total energy consumption was only 120 kWh.m -2 for gas, and 14 kWh.m -2 for electricity from November to April 2011 for a 16°C set point temperature. In average, the heat pump brought 30% of the total heat input. Moreover, it was shown that the energy required by the heat pump was four to five times less than that corresponding to the ventilation-heating technique. This device thus makes it possible to grow plants that are very sensitive to humidity and fungal diseases, while reducing energy consumption as well as fungicide uses

CFD analysis of the climate inside a closed greenhouse at night including condensation and crop transpiration

International audienceHumidity control is a key factor in greenhouse management as it impacts the growth and quality of most greenhouse crops. Low temperature accompanied with high humidity levels for instance may lead to condensation which in turn may create favourable conditions for fungal diseases like botrytis. CFD (Computational Fluid Dynamics) is today widely used to predict the climate inside greenhouses. But up until now, the condensation phenomenon has been hardly addressed in CFD studies. The aim of this work is to analyse the heat and mass transfers occurring inside a closed mono-span glasshouse compartment using CFD simulations and focusing on night-time cases. A 2D transient model which solves the classical RANS equations in combination with the k-ε closure for turbulence was considered. Radiative exchanges between the sky and the components of the greenhouse were considered through a specific submodel. User defined functions were implemented to take account of both condensation along the roof and crop transpiration. The validation of the model was undertaken on the basis of experiments conducted in a 100 m2 Venlo-greenhouse with Impatiens pot plants grown on shelves. Results showed the ability of the model to predict air and leaf temperatures inside the greenhouse as well as air humidity levels. Then, the influence of factors such as the external conditions, heating and glass properties on the greenhouse climate and especially on the condensation process was investigated through a sensitivity analysis. For each case, the heat gain and loss along the inside and outside greenhouse roof were analysed and compared. The results of the simulations clearly show the influence of these factors on the greenhouse air temperature and condensation flux