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Sample records for dynamique des piles

  1. Generalities on the dynamic behaviour of rapid reactors. Preliminary studies on Rapsodie; Generalites sur le comportement dynamique des piles rapides. Etudes preliminaires de rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Campan, J L; Chaumont, J P; Clauzon, P P; Ghesquiere, G; Leduc, J; Schmitt, A P; Zaleski, C P [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1963-07-01

    The study of the dynamic behaviour of fast reactors may be divided into three section: 1. Stability studies around equilibrium power only the linear case was examining. S. Transient studies in the case of usual reactor operation (shut down, scram, etc.) with thermal shocks evaluation, for instance. 3. Explosion studies, for the maximum credible accidents. This report presents the status of the studies performed at the 'Physics Research Department' at Cadarache. Methods used are detailed and illustrated with the results obtained on a preliminary metallic core of the Rapsodie Reactor. (authors) [French] Le comportement dynamique des piles rapides, se presente tout naturellement sous trois aspects: 1. Etude de stabilite autour d'un regime d'equilibre (nous nous sommes bornes ici au cas lineaire). 2. Etude de regimes transitoires lors des operations normales de pile (arret, arret d'urgence, etc.) avec evaluation des chocs thermiques par exemple. 3. Etude des regimes transitoires de caractere explosif lors des accidents les plus graves possibles. Ce rapport presente l'etat des etudes a la date du 20 decembre 1961 a la Section d'Etudes de Piles Rapides a CADARACHE. Les methodes employees ont ete detaillees et illustrees a partir des resultats obtenus sur une premiere version 'combustible metallique' de Rapsodie. (auteurs)

  2. Original Paper Dynamique des peuplements des Parcelles d'Essais ...

    African Journals Online (AJOL)

    permanentes (PFTP) à Bensékou visait à évaluer la dynamique de la population de ... est alors important de mettre en œuvre une sensibilisation de la population locale sur les mérites de la gestion ..... contrôle des PES se sont encore montré.

  3. Safety precautions in atomic pile control (1962); Securite dans le controle des piles atomiques (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    We have been led to study the problem of safety in atomic pile control as a result of our participation on the one hand in the planning of C.E.A. atomic piles, and on the other hand in the pile safety sub omission considering atomic pile safety of operational or planned C.E.A. piles. We have thus had to consider the wishes occurring in piles during their operation and also their behaviour in the dynamic state The present work deals mainly with the importance of intrinsic safety devices, with the influence of reactivity variations on the power fluctuations during accidental operation, and with the development of robust and reliable safety appliances. The starting p accident has been especially studied both for low-flux piles where a compromise is necessary between the response time of the safety appliances and the statistical fluctuations and for high lux piles where xenon poisoning has an effect on the lower limit of the velocity of reactivity liberation. The desirability has been stressed of automation as a safety factor in atomic pile control. The details required for an understanding of the diagrams of the apparatus are given. (author) [French] Nous avons aborde le probleme de la securite dans le controle des piles atomiques a la suite de notre participation d'une part aux avant rojets de piles atomiques du CE.A. et d'autre part a l'examen au sein de la sous ommission de surete des piles, de la securite des piles du CE.A. en fonctionnement ou en projet. Nous avons ete amenes a nous interesser alors aux risques encourus par les piles pendant leur fonctionnement et par la meme a leur comportement en regime dynamique. Ce travail traite principalement de l'importance des securites intrinseques, de l'influence des variations de reactivite sur les evolutions de puissance en regime d'accident et du developpement d'appareillages de securite robustes et de fonctionnement tres sur. L'accident de demarrage a ete particulierement

  4. Safety precautions in atomic pile control (1962); Securite dans le controle des piles atomiques (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    We have been led to study the problem of safety in atomic pile control as a result of our participation on the one hand in the planning of C.E.A. atomic piles, and on the other hand in the pile safety sub omission considering atomic pile safety of operational or planned C.E.A. piles. We have thus had to consider the wishes occurring in piles during their operation and also their behaviour in the dynamic state The present work deals mainly with the importance of intrinsic safety devices, with the influence of reactivity variations on the power fluctuations during accidental operation, and with the development of robust and reliable safety appliances. The starting p accident has been especially studied both for low-flux piles where a compromise is necessary between the response time of the safety appliances and the statistical fluctuations and for high lux piles where xenon poisoning has an effect on the lower limit of the velocity of reactivity liberation. The desirability has been stressed of automation as a safety factor in atomic pile control. The details required for an understanding of the diagrams of the apparatus are given. (author) [French] Nous avons aborde le probleme de la securite dans le controle des piles atomiques a la suite de notre participation d'une part aux avant rojets de piles atomiques du CE.A. et d'autre part a l'examen au sein de la sous ommission de surete des piles, de la securite des piles du CE.A. en fonctionnement ou en projet. Nous avons ete amenes a nous interesser alors aux risques encourus par les piles pendant leur fonctionnement et par la meme a leur comportement en regime dynamique. Ce travail traite principalement de l'importance des securites intrinseques, de l'influence des variations de reactivite sur les evolutions de puissance en regime d'accident et du developpement d'appareillages de securite robustes et de fonctionnement tres sur. L'accident de demarrage a ete particulierement developpe aussi bien pour les piles a bas

  5. Dynamique de structuration spatio-temporelle des populations de ...

    African Journals Online (AJOL)

    Dynamique de structuration spatio-temporelle des populations de familles de macroinvertébrés dans un continuum lac de barrage-effluent-fleuve issu de périmètre irrigué. Bassin de la Volta (Burkina Faso)

  6. Fast neutron breeder reactor Rapsodie - situation of physics, hydraulic, thermal and dynamics studies and studies of stability early in 1963; Pile rapide rapsodie - point des etudes neutroniques, hydrauliques, thermiques et dynamiques et des etudes de stabilite au debut de l'annee 1963

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1964-07-01

    ) [French] Au debut de 1963, il a ete necessaire de faire un choix entre les deux combustibles etudies pour Rapsodie: l'alliage UPuMo avec double gainage Nb et acier inoxydable et l'oxyde mixte UO{sub 2}-PuO{sub 2}. Ce rapport donne les resultats des etudes menees avec les deux types de combustible. On rappelle d'abord les differents modeles qui ont ete etudies et on donne une description detaillee de coeurs alliage et oxyde tels qu'ils sont envisages au debut de 1963. On rapporte ensuite les principales caracteristiques neutroniques des deux coeurs: flux et spectre des neutrons, valeur des barres de securite - compensation, economie des neutrons, puissance specifique, fraction effective des neutrons retardes, temps de vie des neutrons prompts, coefficients de reactivite. On decrit les etudes et essais hydrauliques qui ont ete faits a propos de ces deux coeurs. On discute les criteres qui ont ete a l'origine des calculs de debits. On donne les resultats des essais de pertes de charge, de soulevement des assemblages, de vibration et d'ecoulement fin entre les aiguilles. On discute les constantes utilisees pour les calculs thermiques et on donne les temperatures maximales du sodium et des combustibles alliage et oxyde, les majorations dues aux points chauds et la limitation du taux de combustion de l'aiguille oxyde ayant pour origine la pression des gaz de fission. On rapporte les hypotheses qui ont ete utilisees pour les calculs dynamiques et l'on decrit les differents incidents qui ont ete etudies. On donne les resultats des calculs, pour chaque incident et pour chaque combustible et l'on montre que l'on peut eviter la fusion du combustible ou l'ebullition du sodium, meme dans le cas des hypotheses les plus pessimistes, en agissant sur les caracteristiques de la pile (valeur de la barre de pilotage ou puissance de la pile avec un seul circuit de refroidissement). La stabilite de la pile a ete evaluee avec les hypotheses utilisees pour les calculs dynamiques, a l

  7. dynamique des nouvelles technologies rizicoles en agriculture

    African Journals Online (AJOL)

    USER

    d'adoption : D'une part, au plan macro-économique, l'option d'une politique de soutien ... malheureusement, une contrainte à la réalisation d'une politique nationale de ..... Communauté laïque des missionnaires ... production sous forme de semence, (iii) le ..... série " Sciences économiques et gestion ". ... Transformation de.

  8. Study of the dynamic behaviour of the reactor Rapsodie; Etude du comportement dynamique de la pile rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Abdon, R; Chaigne, M [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1964-07-01

    . The investigation of the control, carried out on analog computer, served to determine the different possible means of starting and changing the conditions of the reactor as well as its automatic control. The calculations were examined in the totality by the construction of a training simulator composed of a board similar to the control board of the reactor, all of whose commands (reactivity and flows) work on an analogue computer which resolves in the real time the dynamic equations of the reactor and which reproduces simultaneously all the parameters representing the state of the installation (power, period, temperatures, etc. ) in the case of various incidents as well as under normal conditions of functioning. (authors) [French] On sait que le developpement des reacteurs surgenerateurs a neutrons rapides pose des problemes nouveaux d'une part dans les domaines mecanique et thermique et d'autre part en ce qui concerne leur comportement dynamique et leur surete. La pile RAPSODIE a ete l'objet de tres nombreuses etudes dynamiques effectuees sur machines analogiques et digitales, pour deux versions du combustible (metal et oxyde). Apres elaboration des modeles mathematiques representatifs de l'ensemble de l'installation (bloc pile et circuit de refroidissement) tant du point de vue neutronique que du point de vue thermodynamique, on a mis au point les schemas analogiques et les codes digitaux utilisables pour mener a bien les simulations d'incidents, de conduite et de stabilite du reacteur. On s'est attache, par rapport aux methodes habituelles a obtenir une precision plus grande, par un decoupage en zones plus fines, par l'emploi de formulations plus representatives du systeme reel, voire solubles analytiquement. Les etudes d'incidents ont ete effectuees par voie analogique pour l'ensemble de l'installation et par voie digitale pour l'etude du bloc pile seul ou de l'installation fonctionnant avec un seul circuit thermique. Un programme complementaire special - qui, a

  9. Influence de l'occupation des terres sur la dynamique des ...

    African Journals Online (AJOL)

    L'objectif de la présente étude est d'évaluer l'impact de mise en culture, des pâturages, des jachères et l'influence des villages sur la dynamique des communautés végétales de la commune de ..... mais il n'y a que peu de recrutement. Au-delà de cinq ans, taille et phytovolume diminuent, témoignant du vieillissement de la ...

  10. Effets des extraits vegetaux sur la dynamique de populations des ...

    African Journals Online (AJOL)

    La présente étude se propose de trouver une alternative de l'utilisation des pesticides chimiques en testant l'effet insecticide des extraits aqueux des feuilles de Hyptis suaveolens, graines de Ricinus communis et de Azadirachta indica contre les ravageurs du niébé en conditions de champ en utilisant le cyperméthrine ...

  11. Dynamique de fréquentation des grands mammifères dans une ...

    African Journals Online (AJOL)

    SARAH

    31 juil. 2016 ... 2016 Dynamique de fréquentation des grands mammifères dans une clairière ... 2Ecole Régionale Post-Universitaire d'Aménagement et de gestion Intégrés des Forêts et ..... épidémiologique et contrôle des stomoxes à la.

  12. Dynamique des populations du foreur des tiges du cacaoyer ...

    African Journals Online (AJOL)

    SARAH

    30 nov. 2014 ... déprédateur dans la région du Haut-Sassandra, la deuxième plus grande région de production de cacao en. Côte d'ivoire. Méthodologie et résultats : L'étude a été réalisée de 2009 à 2013 dans les plantations villageoises de la région du Haut-Sassandra en Côte d'Ivoire. Les variations des taux d'attaques ...

  13. Dynamique de la teneur en carbone et en azote des sols dans les ...

    African Journals Online (AJOL)

    SARAH

    30 nov. 2014 ... INTRODUCTION. L'étude de la dynamique de carbone et de l'azote dans le ... climatique et l'autre de dimension locale, la fertilité des sols. ... situe à la limite méridionale du domaine sahélien, le ..... Soils and global change.

  14. Dynamiques et rôle économique et social du secteur informel des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    L'économie des pays en développement, africain notamment, est caractérisée par la coexistence d'un secteur formel et d'un autre dit informel. ... Ce projet vise à mieux comprendre le dynamique actuelle du secteur informel des TIC et le rôle économique et social qu'il joue au Burkina Faso, au Cameroun et au Sénégal, ...

  15. Évaluation de la dynamique de la transmission du Zika et des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... mais a souligné que la transmission du Zika et ses conséquences graves continueront de représenter un important problème de santé publique. On enregistre encore des lacunes au niveau des connaissances liées à la dynamique de transmission écologique, ou aux facteurs qui ont une incidence sur la propagation du ...

  16. Sur la dynamique et la commande des colonnes multicomposées

    OpenAIRE

    Creff , Yann

    1992-01-01

    ON S'INTERESSE A LA COMMANDE EN QUALITE DE COLONNES A DISTILLER MULTICOMPOSEES, EN ETENDANT AUX COLONNES PSEUDO-BINAIRES DES RESULTATS RECENTS ETABLIS POUR LES COLONNES BINAIRES. ON COMMENCE PAR METTRE EN EVIDENCE LA DIFFICULTE D'ETENDRE DIRECTEMENT LES TECHNIQUES EMPLOYEES DANS LE CAS BINAIRE. ON DEMONTRE DANS CE CADRE UNE PROPRIETE VERIFIEE PAR LE JACOBIEN DES FONCTIONS D'EQUILIBRE LIQUIDE-VAPEUR ET ON AFFINE LA DESCRIPTION GEOMETRIQUE DE LA DYNAMIQUE DU FLASH. ON DEVELOPPE ENSUITE UNE TECH...

  17. Contribution à l'étude des dynamiques identitaires obliques

    African Journals Online (AJOL)

    Conseil pour le développement de la recherche en sciences sociales en Afrique, ... spécifiques, la plupart des continuateurs des études post-coloniales ont eu à ... sociaux et Internet dans les rapports qu'établissent les jeunes Africains avec.

  18. Acteurs, gouvernance et dynamiques de projet dans la concurrence des territoires en tourisme

    OpenAIRE

    Suchet, André

    2016-01-01

    Cette thèse propose une géographie des dynamiques du sport et du tourisme en Pyrénées, au regard de la situation dans les Alpes. À la suite notamment du volume fondateur de Chadefaud (1988), il s’agit de traiter comment les dynamiques du tourisme en Pyrénées imitent, concurrencent, ou se détachent du modèle alpin. Une fois débarrassé de toute idée de déterminisme physique au profit d’un postulat constructiviste, il devient possible d’interroger la fabrication d’un rapport de domination entre ...

  19. Connaissances et perceptions locales de la dynamique des ...

    African Journals Online (AJOL)

    chlorhydrique) et pH eau, par la méthode électrométrique au pH mètre à électrode de verre (AFNOR, 1999) . Une analyse diachronique des surfaces gravillonnaires a été réalisée à partir de la classification supervisée des images de type Landsat sur trois dates différentes : images Landsat ETM+ pour les périodes 1987 et.

  20. Influence des actions anthropiques sur la dynamique spatio ...

    African Journals Online (AJOL)

    Sci-Nat

    Située à proximité de Kinshasa, la province du Bas-Congo (R.D. Congo) est l'une des principales pourvoyeuses en produits vivriers de cette ville. Par conséquent, l'augmentation de la pression sur les ressources naturelles s'accentue. L'analyse diachronique du paysage peut servir à montrer l'effet des actions ...

  1. Postface : La gestion des risques naturels est une dynamique

    NARCIS (Netherlands)

    Jaboyedoff, M.; Charriere, M.K.M.; Derron, M.H.; Nicolet, P.; Sudmeier-Rieux, K.

    2013-01-01

    Les risques sont contrôlés par de nombreux facteurs dont, en premier lieu, les dangers, exprimés par leur fréquence (aléa) à une intensité donnée, mais aussi relativement à un fonctionnement de la société. La gestion des risques, liés aux dangers naturels, implique de les évaluer, en premier lieu,

  2. Dynamique de nanobulles et nanoplasmas generes autour de nanoparticules plasmoniques irradiees par des impulsions ultracourtes

    Science.gov (United States)

    Dagallier, Adrien

    L'emergence des lasers a impulsion ultrabreves et des nanotechnologies a revolutionne notre perception et notre maniere d'interagir avec l'infiniment petit. Les gigantesques intensites generees par ces impulsions plus courtes que les temps de relaxation ou de diffusion du milieu irradie induisent de nombreux phenomenes non-lineaires, du doublement de frequence a l'ablation, dans des volumes de dimension caracteristique de l'ordre de la longueur d'onde du laser. En biologie et en medecine, ces phenomenes sont utilises a des fins d'imagerie multiphotonique ou pour detruire des tissus vivants. L'introduction de nanoparticules plasmoniques, qui concentrent le champ electromagnetique incident dans des regions de dimensions nanometriques, jusqu'a une fraction de la longueur d'onde, amplifie les phenomenes non-lineaires tout en offrant un controle beaucoup plus precis de la deposition d'energie, ouvrant la voie a la detection de molecules individuelles en solution et a la nanochirurgie. La nanochirurgie repose principalement sur la formation d'une bulle de vapeur a proximite d'une membrane cellulaire. Cette bulle de vapeur perce la membrane de maniere irreversible,entrainant la cellule a sa mort, ou la perturbe temporairement, ce qui permet d'envisager de faire penetrer dans la cellule des medicaments ou des brins d'ADN pour de la therapie genique. C'est principalement la taille de la bulle qui va decider de l'issue de l'irradiation laser. Il est donc necessaire de controler finement les parametres du laser et la geometrie de la nanoparticule afin d'atteindre l'objectif fixe. Le moyen le plus direct a l'heure actuelle de valider un ensemble de conditions experimentales est de realiser l'experience en laboratoire,ce qui est long et couteux. Les modeles de dynamique de bulle existants ne prennent pas en compte les parametres de l'irradiation et ajustent souvent leurs conditions initiales a partir de leurs mesures experimentales, ce qui limite la portee du modele au cas pour

  3. Dynamique de l'occupation des terres et état de la flore et de la ...

    African Journals Online (AJOL)

    SARAH

    31 déc. 2016 ... dynamique et sensible aux changements notamment les modifications de ... Contrôle-terrain : Pour le contrôle-terrain, 80 points GPS ont été relevés dans les ..... Sabi Monra A, 2015. Gestion des terroirs et conservation de la ...

  4. ETUDE DU COMPORTEMENT MECANIQUE DES ACIERS HYPEREUTECTOIDES DANS LE DOMAINE DE TEMPERATURE INTERCRITIQUE DYNAMIQUE

    Directory of Open Access Journals (Sweden)

    R GHERIANI

    2001-06-01

    Full Text Available L'étude que nous présentons contribue à une meilleure compréhension de l'influence de la vitesse de déformation et de la température sur le comportement mécanique des aciers hypereutectoïdes dans le domaine de température intercritique dynamique. Les courbes expérimentales obtenues en torsion présentent un intérêt notable dans la mesure où elles permettent de caractériser le comportement mécanique de l'acier 100C6; de plus, elles fournissent  des informations précieuses sur la capacité maximale de déformation de l'alliage. Les essais de torsion, menés jusqu'à rupture des éprouvettes, permettent d'effectuer un classement des matériaux selon leur ductilité. Les résultats obtenus sur l'acier 100C6 ont permis de préciser le comportement mécanique à tiède  de cet acier. Les aciers hypoeutectoïdes présentent, dans les domaines de température compris entre Ac1 et Ac3 en condition dynamique, une capacité de déformation élevée résultant de l'évolution, en cours de déformation, des phases a et g et de leurs mécanismes d'adoucissement. Nous nous sommes alors posé la question: quel est le comportement d'un acier hypereutectoïde, donc ne présentant  pas de domaine biphasé (a + g à l'équilibre, lorsqu'il est déformé à une température supérieure à Ac1?

  5. Digitalisation in atomic pile control (1962); La digitalisation dans le controle des piles atomiques (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    A brief survey is first given of the general theorems of Boodle's algebra and of sequence systems using D.A. Huffmans theory. Some indications are then given concerning the setting-up and the operation of digital computers and also of the principal codes used in digital techniques. It is then shown how digitalisation in atomic pile control makes it possible to use new techniques having the following advantages in particular: greater working safety, a higher degree of centralisation, and suppression of the linear elements. A few examples are given of the application of these techniques to control, particularly with respect to the measurement of the neutronic power and of the period and also of course, to the treatment of the data and the sequence automatisms. The advantage of using digital techniques in the shutdown channels is also examined. Finally a review is given of the technology and the viability of the control devices used. (author) [French] On rappelle d'abord ici les theoremes generaux de l'algebre de Boole et des systemes a sequences en s'appuyant sur la theorie de D.A. Huffmann. On donne ensuite quelques indications sur l'agencement et le fonctionnement des calculateurs digitaux ainsi que les principaux codes utilises dans les techniques digitales. On montre alors comment la digitalisation dans le controle des piles atomiques permet d'utiliser de nouvelles techniques presentant principalement les avantages suivants: securite de fonctionnement plus grande, centralisation plus elevee et suppression des elements lineaires. Un certain nombre d'exemples sont donnes sur l'application de ces techniques au controle, particulierement en ce qui concerne la mesure de la puissance neutronique, de la periode et aussi bien entendu du traitement des informations et des automatismes a sequences. On analyse aussi l'avantage de l'utilisation des techniques digitales dans les chaines de securite. Enfin, un apercu est donne sur la technologie et la fiabilite des dispositifs

  6. Graphite reactor physics; Physique des piles a graphite

    Energy Technology Data Exchange (ETDEWEB)

    Bacher, P; Cogne, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Noc, B [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    The study of graphite-natural uranium power reactor physics, undertaken ten years ago when the Marcoule piles were built, has continued to keep in step with the development of this type of pile. From 1960 onwards the critical facility Marius has been available for a systematic study of the properties of lattices as a function of their pitch, of fuel geometry and of the diameter of cooling channels. This study has covered a very wide field: lattice pitch varying from 19 to 38 cm. uranium rods and tubes of cross-sections from 6 to 35 cm{sup 2}, channels with diameters between 70 and 140 mm. The lattice calculation methods could thus be checked and where necessary adapted. The running of the Marcoule piles and the experiments carried out on them during the last few years have supplied valuable information on the overall evolution of the neutronic properties of the fuel as a function of irradiation. More detailed experiments have also been performed in Marius with plutonium-containing fuels (irradiated or synthetic fuels), and will be undertaken at the beginning of 1965 at high temperature in the critical facility Cesar, which is just being completed at Cadarache. Spent fuel analyses complement these results and help in their interpretation. The thermalization and spectra theories developed in France can thus be verified over the whole valid temperature range. The efficiency of control rods as a function of their dimensions, the materials of which they are made and the lattices surrounding them has been measured in Marius, and the results compared with calculation on the one hand and with the measurements carried out in EDF 1 on the other. Studies on the control proper of graphite piles were concerned essentially with the risks of spatial instability and the means of detecting and controlling them, and with flux distortions caused by the control rods. (authors) [French] Entreprise il y a dix ans a l'occasion de la construction des piles de Marcoule, l'etude de la

  7. Dynamique des ressources naturelles dans le Parc national de Manda: Cartographie et analyse pour le Développement durable

    Science.gov (United States)

    Ballah Solkam, Rosalie; Médard, Ndoutorlengar

    2018-05-01

    Au Tchad, le réseau d'aires protégées couvre près de 10,2% de la surface du pays et reste globalement représentatif de toute la diversité des écosystèmes de la région. Cependant, ce réseau n'est pas constitué d'écosystèmes intacts car de nombreuses altérations y ont été apportés (certaines espèces sont déjà au seuil critique d'extinction (Addax, gazelle dama, lamantin), voire ont disparu (Rhinocéros noir et blanc, Oryx)) surtout dans les parcs nationaux. Ce qui nous amène à nous interroger sur la dynamique des ressources naturelles et le degré de conservation du parc national de Manda? Une évaluation de la diversité biologique et des ressources hydrographiques de 1951 à 1999 sur la base de la bibliographie existante, de la carte topographique de 1956, des images satellitaires Landsat 5 et 7 TM et ETM+ de 2 périodes (1986, 1999), complétée par des interviews semi-structurés et des transects sur le terrain, permettra de mieux appréhender la dynamique des ressources et les actions de conservation de la biodiversité réalisées à cet effet. Les résultats montrent une dynamique progressive de la faune de 1951 à 1970, puis une dynamique régressive de 1970 à 1989. Après cette tumultueuse période, un repeuplement du parc s'opère de 1989 à 2002. Par contre, la flore est relativement bien conservée avec quelques cours d'eau, des mares, champs et plantations. Et cela grâce aux multiples projets de conservation de la biodiversité. La promotion de l'écotourisme serait une alternative au développement durable de ce parc.

  8. The dynamic behaviour of heat exchangers; Etude du comportement dynamique des echangeurs de chaleur

    Energy Technology Data Exchange (ETDEWEB)

    Fonteray, J; Rozenholc, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    In order to study the dynamics of nuclear power plants, one needs mathematical models made up of ordinary differential equations. This report deals with models for heat exchangers. These models allow exact evaluations of the temperatures for any steady state. The deformation of the temperature maps during transients is taken into account. To do this, average temperatures are evaluated keeping In mind, on one hand the partial differential equations, on the other hand, the physical phenomenons which are involved. Seven ordinary differential equations at most, are necessary for one heat exchanger. Theses models were compared with mathematically exact ones and also with experimental results, that EDF was able to measure on EDF-1 heat exchangers. The results appear to be correct. (authors) [French] Les etudes de dynamique sur les centrales nucleaires exigent l'elaboration de modeles apparaissant sous forme d'equations differentlelles ordinaires. Ce rapport est consacre a la recherche de modeles d'echangeurs. Dans ces modeles les temperatures sont calculees exactement pour n'importe quel regime permanent. Pour tenir compte de la deformation des distributions de temperature en regime transitoire, on evalue les temperatures moyennes dans l'echangeur en s'appuyant, d'une part, sur les equations aux derivees partielles et, d'autre part, sur une analyse des phenomenes physiques. Les modeles contiennent au plus sept equations differentielles ordinaires. Ces modeles ont ete compares aux modeles mathematiques exacts et aussi a des resultats experimentaux, obtenus par l'EDF, sur les echangeurs d'EDF-1. Les resultats paraissent satisfaisants. (auteurs)

  9. Dynamical behaviour of fast electrons in a crystalline lamella; Comportement dynamique des electrons rapides dans une lamelle cristalline

    Energy Technology Data Exchange (ETDEWEB)

    Perio, Pierre; Tournarie, Max [Commissariat a l' energie atomique et aux energies alternatives - CEA (France)

    1960-07-01

    The substitution of the reciprocal space by a 'mixed space' simplifies the use of the dynamical equation. The Friedel law is preserved. The Ventzel-Kramers-Brillouin-Rayleigh approximation appears as a planar approximation and explains the evolution of some images in electron microscopy. Reprint of a paper published in Comptes rendus des seances de l'Academie des Sciences, t. 249, p. 2218-2220, sitting of 23 November 1959 [French] La substitution d'un 'espace mixte' a l'espace reciproque facilite la manipulation de l'equation dynamique. La loi de Friedel est conservee. L'approximation Ventzel-Kramers-Brillouin-Rayleigh apparait comme une approximation plane et explique l'evolution de certaines images en microscopie electronique. Reproduction d'un article publie dans les Comptes rendus des seances de l'Academie des Sciences, t. 249, p. 2218-2220, seance du 23 novembre 1959.

  10. Etude des phenomenes dynamiques ultrarapides et des caracteristiques impulsionnelles d'emission terahertz du supraconducteur YBCO

    Science.gov (United States)

    Savard, Stephane

    Les premieres etudes d'antennes a base de supraconducteurs a haute temperature critique emettant une impulsion electromagnetique dont le contenu en frequence se situe dans le domaine terahertz remontent a 1996. Une antenne supraconductrice est formee d'un micro-pont d'une couche mince supraconductrice sur lequel un courant continu est applique. Un faisceau laser dans le visible est focalise sur le micro-pont et place le supraconducteur dans un etat hors-equilibre ou des paires sont brisees. Grace a la relaxation des quasiparticules en surplus et eventuellement de la reformation des paires supraconductrices, nous pouvons etudier la nature de la supraconductivite. L'analyse de la cinetique temporelle du champ electromagnetique emis par une telle antenne terahertz supraconductrice s'est averee utile pour decrire qualitativement les caracteristiques de celle-ci en fonction des parametres d'operation tels que le courant applique, la temperature et la puissance d'excitation. La comprehension de l'etat hors-equilibre est la cle pour comprendre le fonctionnement des antennes terahertz supraconductrices a haute temperature critique. Dans le but de comprendre ultimement cet etat hors-equilibre, nous avions besoin d'une methode et d'un modele pour extraire de facon plus systematique les proprietes intrinseques du materiau qui compose l'antenne terahertz a partir des caracteristiques d'emission de celle-ci. Nous avons developpe une procedure pour calibrer le spectrometre dans le domaine temporel en utilisant des antennes terahertz de GaAs bombarde aux protons H+ comme emetteur et detecteur. Une fois le montage calibre, nous y avons insere une antenne emettrice dipolaire de YBa 2Cu3O7-delta . Un modele avec des fonctions exponentielles de montee et de descente du signal est utilise pour lisser le spectre du champ electromagnetique de l'antenne de YBa 2Cu3O7-delta, ce qui nous permet d'extraire les proprietes intrinseques de ce dernier. Pour confirmer la validite du modele

  11. Analyse géographique et modélisation des dynamiques d’urbanisation à La Réunion

    Directory of Open Access Journals (Sweden)

    Pascal Thinon

    2007-07-01

    Full Text Available Cet article propose un prototype de modèle d’interprétation des dynamiques urbaines sur l’Ile de la Réunion. En entrée, le modèle combine un ensemble de champs géographiques jouant en faveur ou en défaveur de l’urbanisation ; en sortie, il indique une propension à l’urbanisation de chaque lieu. Il est conçu de manière à permettre une analyse exploratoire de ces dynamiques selon une approche heuristique. Les premiers résultats ont permis d’obtenir, sur l’ensemble de l’île, une carte de la propension à l’urbanisation, jugée satisfaisante eu égard aux dynamiques observées entre 1989 et 2002 ; un premier scénario d’évolution, concernant les espaces de savanes à l’ouest de l’île, est également proposé. Les premiers travaux sur ce modèle, encore à un stade préliminaire, sont encourageants mais soulèvent de nombreuses questions concernant notamment le calibrage des facteurs et leur rôle respectif, l’intégration de nouveaux champs comme le voisinage, l’analyse des résidus, la mesure de la qualité du modèle ou bien encore la mobilisation de ce type de modèle comme outil d’accompagnement de projets de territoires.

  12. Nouvelles fonctions de l'agriculture et dynamiques des exploitations: une analyse chorématique dans les monts d'Ardèche

    Directory of Open Access Journals (Sweden)

    Muriel Bonin

    2001-06-01

    Full Text Available Les modèles spatiaux sont utilisés pour l'analyse des trajectoires d'exploitations agricoles pour mettre en évidence les liens entre les transformations socio-économiques et les dynamiques de territoires. Les traits de dynamiques spatiales sont identifiés et utilisés pour analyser l'impact de l'introduction de l'agritourisme dans les exploitations dans le Parc naturel régional des monts d'Ardèche.

  13. Étude de la dynamique stationnelle des populations des culicidés ...

    African Journals Online (AJOL)

    La province de Sidi Slimane (Maroc) par son climat et sa position dans la plaine du Gharb en tant qu'une zone d'inondation, engendre une grande variété de gîtes larvaires culicidiens. Les autorités sanitaires de la province adoptent la stratégie nationale qui vise essentiellement le maintien de l'élimination des maladies ...

  14. Radiation hazards in the neighbourhood of uranium reactors; Dangers des rayonnements aupres des piles a uranium

    Energy Technology Data Exchange (ETDEWEB)

    Joffre, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1956-07-01

    Radiation hazards near uranium reactors may be divided in two groups. Hazards when the reactor is normally operating: {gamma} radiation from hot uranium or air contamination by fission gases, {gamma} radiation or contamination by the coolant (air, nitrogen, heavy-water), {gamma} radiation from radioisotopes. Hazards in the case of an accident: presence of hot uranium in the atmosphere, soil contamination. (author) [French] Les dangers d'irradiation aupres des piles a uranium sont a classer essentiellement en deux groupes. Les dangers existant aupres d'une pile exploitee normalement: irradiation {gamma} par l'uranium irradie ou contamination de l'air par des gaz de fission, irradiation {gamma} ou contamination par les fluides de refroidissement (air, azote, eau lourde), irradiation {gamma} par les radioelements fabriques. Les dangers en cas d'accident survenant a un reacteur en fonctionnement, ayant pour consequence : la presence dans l'air d'uranium irradie, la contamination du sol. (auteur)

  15. Caracterisation environnementale des emissions atmospheriques d'une source fixe et creation d'un outil de gestion dynamique =

    Science.gov (United States)

    Fournier, Marie-Claude

    moyen pour sensibiliser le personnel a leur consommation energetique ainsi qu'a leur role dans la lutte contre les emissions polluantes et les gaz a effets de serre. En outre, ce type d'outil a pour principale fonction de generer des rapports dynamiques pouvant s'adapter a des besoins precis. Le decoupage coherent de l'information associe a un developpement par modules offre la perspective d'application de l'outil pour d'autres types d'activites. Dans ce cas, il s'agit de definir la part commune avec les modules existants et planifier les activites de developpement specifiques selon la meme demarche que celle presentee dans le present document.

  16. Politiques et dynamique des systèmes de production: comment concilier défi alimentaire, compétitivité et environnement ?

    OpenAIRE

    Chatellier, Vincent; Dupraz, Pierre

    2011-01-01

    Cette communication propose une réflexion portant sur l’influence des politiques publiques (commerciale, agricole et environnementale) sur la dynamique des systèmes de production en agriculture. Elle rappelle, dans un premier temps, que les politiques commerciales définies dans le cadre des accords de l’OMC contribuent à une libéralisation accentuée des marchés agricoles internationaux. En se focalisant sur les principales productions agricoles développées dans l’Union européenne (céréales, l...

  17. Control panel for radiation around reactors (1963); Tableaux de controle des radiations aupres des piles (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Candes, P; Barthoux, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    This report outlines the general philosophy of radiation control in French reactors and their annexes. The supervision is carried out continuously from a central control panel on which appear all the measurements made and the alarm signals. The equipment is described; one item makes it possible to measure simultaneously the radioactive dusts and gases. The specifications of the alarm system, which is considered to be the most important are given. Finally a new measuring technique is proposed which makes it possible to reduce considerably the cost of radiation control while at the same time providing the results in a form in which they can be easily treated, in particular in the case of the calculation of total doses. (authors) [French] Ce rapport definit la philosophie generale du controle des radiations dans les piles francaises et dans leurs annexes. La surveillance se fait d'une maniere continue a partir d'un tableau de controle centralise ou sont reportees toutes les mesures et les signalisations d'alarme. On decrit les appareils utilises, dont un permet la mesure simultanee des poussieres et gaz radioactifs, et on definit les specifications de la fonction alarme qui est consideree comme la plus importante. Enfin on propose une nouvelle technique de mesure qui permettrait de reduire considerablement le cout du controle des radiations tout en fournissant des resultats plus facilement exploitables, en particulier pour le calcul des doses integrees. (auteurs)

  18. Diversité et dynamique des Salmonella isolées de la laitue (Lactuca ...

    African Journals Online (AJOL)

    SARAH

    30 nov. 2017 ... Objectif : Au Niger, l'agriculture maraîchère réalisée dans les zones urbaines et péri-urbaines utilise les eaux usées souvent très ... La production des laitues a pour principale source d'arrosage, les eaux des caniveaux. (41,67%). ...... avec des antiseptiques et ou des désinfectants comme l'eau de javel ...

  19. Dynamique de la nappe et qualites physico-chimiques des eaux ...

    African Journals Online (AJOL)

    resultat est conforme a celui des cartes piezo- metriques elaborees en 1993 et 2007 [19,20]; done la nappe suit le modele topographique et le lac constitue une zone de convergence des eaux. ©UBMA-2013. 88. F. Zahi et al. L' examen des cartes piezometriques montrent que les parties Sud et Sud-Est du lac Fetzara se.

  20. Special concretes for protection in piles (1963); Les betons speciaux dans la protection des piles (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Condat, M.J.; Lafore, P.; Rastoin, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1963-07-01

    The report reviews the main concretes used for the protection of reactors. First are examined the general factors affecting the selection of concretes for protection; some of the general aspects of radiation attenuation (fast and thermal neutrons, {gamma}) are then recalled. After an enumeration of the qualities and defects of conventional concretes, desirable or possible improvements are proposed: introduction of heavy elements for increasing the efficiency with respect to fast neutrons and {gamma}; increase in the hydrogen content (as H{sub 2}O), addition of absorbent products (B, Li, rare earths) for thermal neutron capture. A list is given of the principal products used for this purpose. Finally there is a rapid review of the preparation, the stability with time, and the resistance to radiation and to heat. Appendices and tables give details and numerical values. Appendix 1 deals with the question of water in concretes. Appendix 2 gives a classification of concretes based mainly on their density. At the end, ten tables give the compositions and values of the physical and mechanical characteristics of sixteen particularly typical concretes. (authors) [French] Le rapport passe en revue les principaux betons utilisables pour la protection des reacteurs. On examine d'abord les facteurs generaux influencant la selection des betons de protection; on rappelle ensuite brievement les aspects generaux de l'attenuation des rayonnements (neutrons rapides, neutrons thermiques, {gamma}). Apres avoir rappele les qualites et les defauts des betons classiques, on fait ressortir les perfectionnements souhaitables ou necessaires: introduction d'elements lourds pour ameliorer l'efficacite contre les neutrons rapides et les {gamma}; augmentation de la teneur en H (en H{sub 2}O); addition de corps absorbants (B, Li, terres rares) pour capturer les neutrons thermiques. On enumere les principaux corps utilises a cet effet. On termine par un tres rapide apercu sur

  1. Special concretes for protection in piles (1963); Les betons speciaux dans la protection des piles (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Condat, M J; Lafore, P; Rastoin, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1963-07-01

    The report reviews the main concretes used for the protection of reactors. First are examined the general factors affecting the selection of concretes for protection; some of the general aspects of radiation attenuation (fast and thermal neutrons, {gamma}) are then recalled. After an enumeration of the qualities and defects of conventional concretes, desirable or possible improvements are proposed: introduction of heavy elements for increasing the efficiency with respect to fast neutrons and {gamma}; increase in the hydrogen content (as H{sub 2}O), addition of absorbent products (B, Li, rare earths) for thermal neutron capture. A list is given of the principal products used for this purpose. Finally there is a rapid review of the preparation, the stability with time, and the resistance to radiation and to heat. Appendices and tables give details and numerical values. Appendix 1 deals with the question of water in concretes. Appendix 2 gives a classification of concretes based mainly on their density. At the end, ten tables give the compositions and values of the physical and mechanical characteristics of sixteen particularly typical concretes. (authors) [French] Le rapport passe en revue les principaux betons utilisables pour la protection des reacteurs. On examine d'abord les facteurs generaux influencant la selection des betons de protection; on rappelle ensuite brievement les aspects generaux de l'attenuation des rayonnements (neutrons rapides, neutrons thermiques, {gamma}). Apres avoir rappele les qualites et les defauts des betons classiques, on fait ressortir les perfectionnements souhaitables ou necessaires: introduction d'elements lourds pour ameliorer l'efficacite contre les neutrons rapides et les {gamma}; augmentation de la teneur en H (en H{sub 2}O); addition de corps absorbants (B, Li, terres rares) pour capturer les neutrons thermiques. On enumere les principaux corps utilises a cet effet. On termine par un tres rapide apercu sur la mise en oeuvre, la

  2. Angio-RM morphologique et dynamique sans injection de contraste dans l’exploration des pathologies neurovasculaires à l’étage cervical et encéphalique

    OpenAIRE

    Raoult , Hélène

    2014-01-01

    ProblématiqueL’angio-IRM (ARM) est devenue incontournable dans la prise en charge des pathologies neurovasculaires. Elle permet en effet d’évaluer les pathologies modifiant la dynamique circulatoire, telles les sténoses artérielles, plus fréquentes à l’étage cervical et générant des flux sanguins accélérés voire turbulents en amont et ralentis en aval; ou bien les shunts artério-veineux, telles les malformations artério-veineuses encéphaliques, caractérisés par des flux accélérés et complexes...

  3. Dynamique de transfert des matières organiques et inorganiques le long du continuum fluvial de la Garonne : impact de la retenue de Malause

    OpenAIRE

    Mamoudou, Mohamadou

    2008-01-01

    Les fleuves sont à l'origine des transferts de matières organiques et inorganiques des continents vers les océans. Ces matières peuvent être séparées par filtration (généralement à 0,45 ou 0,22µm) entre une phase particulaire et une phase dissoute. Le devenir des formes organiques va dépendre de leurs origines. Les formes labiles sont souvent rapidement minéralisées lors de leur transfert tandis que les formes réfractaires ont un comportement conservatif. Nous avons étudié la dynamique de tou...

  4. Le logement social urbain et la dynamique spatiale. Stratégie des acteurs décideurs à Oran (1990-2000)

    OpenAIRE

    Said, Aïmène

    2013-01-01

    Le constat établi depuis plus d’une décennie, sur la ville d’Oran, fait état d’un mouvement de développement urbain assez intense. Cette dynamique urbaine bien que périphérique se caractérise par une production massive de logements. Avec ses diverses configurations immobilières, le logement social tient une place centrale dans cette production, pour devenir et de loin, le premier consommateur foncier. Notre article tente de suivre l’apport des filières de logement social dans le tracé urbain....

  5. dynamique agraire des agro ecosystemes de bas-fonds au centre

    African Journals Online (AJOL)

    USER

    est caractérisée par la présence de sols ferrugineux tropicaux et de sols hydromorphes, une hétérogénéité dans la dégradation du couvert végétal, une moyenne pluviométrique de. 1 100 mm. Sur le plan morpho-structural, celle- ci est caractérisée par une gamme variée de collines granito-gneissiques, des sols constitués.

  6. Dynamique de fréquentation des grands mammifères dans une ...

    African Journals Online (AJOL)

    SARAH

    31 juil. 2016 ... RÉSUMÉ. Objectifs : Dans le but de connaitre les animaux fréquentant les clairières (ou Baï) forestières au Gabon, une étude sur la fréquentation du Baï de Momba par les grands mammifères a été conduite durant la petite saison des pluies pendant deux mois du 19 février au 13 mars 2012. Méthodologie ...

  7. La gestion dynamique des varietes d'ignames dans le systeme ...

    African Journals Online (AJOL)

    Les origines de la diversité variétale des ignames et le maintien de cette diversité ont été étudiés dans 240 exploitations du Bénin réparties dans huit terroirs, 150 ans l'aire culturelle Bariba (sous-préfecture de Sinendé de juin à octobre 1999) et 90 dans l'aire Nagot (sous-préfecture de Banté, de juin à octobre 2000).

  8. Diversité et dynamique des Salmonella Lactuca sativa L.) dans les ...

    African Journals Online (AJOL)

    Objectif: Au Niger, l'agriculture maraîchère réalisée dans les zones urbaines et péri-urbaines utilise les eaux usées souvent très souillées par la matière fécale humaine et animale pour l'irrigation. Cette étude a évalué la prévalence et la diversité des Salmonella isolées de la laitue dans différents sites maraichers du Niger.

  9. Lattice Dynamics of Transition Metals; Dynamique de Reseau des Metaux de Transition

    Energy Technology Data Exchange (ETDEWEB)

    Woods, A. D.B. [Chalk River Nuclear Laboratories, Chalk River, ON (Canada)

    1965-04-15

    'onde) pour les modes de vibration normaux de plusieurs cristaux de metaux de transition-a structure cubique centree ont fait recemment l'objet de mesures a la temperature ambiante. Les courbes de dispersion relatives au niobium, etablies par Nakagawa et Woods, presentent des particularites tres exceptionnelles et on n'a pu faire concorder les resultats obtenus avec la theorie a l'aide d'un modele Born et von Karman qu'en tenant compte des interactions englobant des voisins tres eloignes (au-dela du huitieme). En procedant ulterieurement a des mesures sur le tantale, Woods a obtenu des resultats tres semblables, ce qui n'est guere surprenant puisque le niobium et le tantale figurent dans la colonne V du tableau de la classification periodique et qu'ils possedent des proprietes electroniques analogues sous de nombreux rapports. Les courbes de dispersion etablies par Woods et Chen pour le molybdene et par Chen et Brockhouse pour le tungstene ont montre que si ces deux metaux qui figurent dans la colonne VI du tableau ont des relations de dispersion semblables l'une a l'autre, ces relations different sensiblement de celles des metaux de la colonne V, niobium et tantale. Les caracteristiques generales de la relation v(q) pour le molybdene et le tungstene peuvent etre decrites avec une grande precision au moyen d'un modele Born et von Karman de forces tenant compte d'une structure a symetrie axiale englobant le troisieme voisin, bien que plusieurs caracteristiques importantes ne soient pas reproduites par ce modele. Pour le molybdene, une de ces caracteristiques est une anomalie frappante de la branche (L) longitudinale [{zeta}{zeta}{zeta}] ou la frequence passe de v 6.3 x 10{sup 12} c/s pour {zeta} = 0.92 to v= 5.5 x 10{sup 12} c/s pour {zeta} = 1.0. Si cette caracteristique et d'autres, qui ont aussi ete observees, sont des anomalies de Kohn, leurs positions sont compatibles avec les dimensions de la surface de Fermi des metaux de la colonne V, proposees par Lomer. On peut donc

  10. Les piles à combustible. Bilan des travaux de recherches. Perspectives Fuel Cells. Review of Research. Outlook

    Directory of Open Access Journals (Sweden)

    Breelle Y.

    2006-11-01

    Full Text Available Cet article fait le point, sous forme résumée, des travaux de recherches et de développement menés par l'Institut Français du Pétrole (IFP depuis vingt ans dans le domaine des piles à combustible : sélection des filières directes conduisant au choix de la pile hydrogène-air basse température à électrolyte basique, mise au point des générateurs à hydrogène alimentés en méthanol. On présente les résultats obtenus et les conclusions des enquêtes effectués dans le domaine des groupes électrogènes et des applications spéciales, dans celui de la traction automobile et dans celui de la production massive d'électricité. This article reviews and sums up the research and development done by Institut Français du Pétrole (IFP in the last 20 years in the field of fuel cells, including the selection of direct methods leading to the choice of low-temperature basic-electrolyte hydrogen/air cells and the development of methanol-powered hydrogen generators. The results obtained are desceibed along with the conclusions of surveys made in the field of electric generators and special applications in the fields of automotive traction and massive electricity production.

  11. L'essor des métiers du conseil : dynamiques et tensions

    Directory of Open Access Journals (Sweden)

    Jean-François Orianne

    2010-02-01

    Full Text Available L'activité de conseil a longtemps constitué une fonction rare et éminente. Max Weber consacre quelques pages à cette figure emblématique du « conseiller (ou guide du prince » (Weber, 1963, p. 136, qui œuvre dans l'ombre de dirigeants politiques au sein des sphères du pouvoir empreintes de prestige. Ce numéro thématique de SociologieS, portant sur les métiers du conseil, rend compte d'une évidente démocratisation de cette activité. Le prince est désormais produit en série. Le plus irremplaça...

  12. L'impact de Quizlet sur la dynamique motivationnelle des élèves lors de l'apprentissage du vocabulaire allemand

    OpenAIRE

    André, Joanne; Berrio, Lucas; Pellet, Jean-Philippe

    2017-01-01

    Pour ce travail, nous nous sommes intéressés à l'effet que pouvait avoir les TIC sur la motivation des élèves. Nous nous sommes penchés sur la plate-forme web Quizlet qui propose différents outils pour réviser un contenu préalablement défini par l'enseignant. Ainsi, nous avons dirigé notre recherche sur l'impact de Quizlet sur la dynamique motivationnelle des élèves dans le cadre de l'apprentissage du vocabulaire allemand. Nous comparons cette méthode d'apprentissage avec les méthodes dites t...

  13. Piles used for the nuclear control of materials; Empilements pour le controle nucleaire des materiaux

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V; Sautiez, B; Bailly du Bois, B; Tretiakoff, O; Thome, P; Vidal, R; Koppel Martelly, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The devices which make it possible to check on the nuclear qualities of the materials used in reactor construction are described. These verifications bear on substantial masses of materials, following the last stage of their machining. The components found in all these are a graphite pile into which the material to be investigated is inserted, a source of neutrons made up of an Ra-Be system, and a proportional BF{sub 3} counter. The devices described here bear on checking graphite, beryllium oxide and uranium absorption, as well as on a verification of the {sup 235}U content of fuel elements. (author)Fren. [French] On decrit des dispositifs permettant de controler les qualites nucleaires de materiaux utilises dans la construction des piles. Ce controle s'effectue sur des masses importantes de materiaux apres la phase finale d'usinage. Ces dispositifs ont en commun un empilement de graphite recevant le materiau a etudier, une source de neutrons de Ra-Be et un compteur proportionnel a BF{sub 3}. Les dispositifs decrits concernent le controle de l'absorption du graphite, de la glucine et de l'uranium, ainsi que le controle de la teneur en {sup 235}U des elements de combustion. (auteur)

  14. Bascule d'un modèle poutre à un modèle 3D en dynamique des machines tournantes

    OpenAIRE

    Tannous , Mikhael; Cartraud , Patrice; Dureisseix , David; Torkhani , Mohamed

    2013-01-01

    National audience; Les problèmes de machines tournantes incluant un contact rotor-stator, nécessitent un maillage 3D de la zone de contact. Cependant, un modèle 3D pour toute la durée de simulation conduit à des temps de calcul rédhibitoires. Or un modèle poutre est suffisant pour décrire la dynamique de la machine tournante hors contact. Une stratégie qui permet d'utiliser un modèle poutre et un autre 3D, pendant deux phases différentes durant la même simulation, permet donc de gagner en tem...

  15. New trends in pile safety instrumentation; Les tendances nouvelles dans l'instrumentation de securite des piles

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J.

    1961-04-19

    This report addresses the protection of nuclear piles against damages due to operation incidents. The author discusses the current trends in the philosophy of safety of atomic power piles, identifies the parameters which define safety systems, presents tests to be performed on safety chains, comments the relationship between safety and the decrease of the number of pile inadvertent shutdowns, discusses the issues of instrument failures and chain multiplicity, comments the possible improvement of the operation of elements which build up safety chains (design simplification, development of semiconductors, replacement of electromechanical relays by static relays), the role of safety logical computers and the development of automatics in pile safety, presents automatic control as a safety factor (example of automatic start-up), and finally comments the use of fuses.

  16. Apparatus for examination of irradiated fuel elements of industrial reactors at Marcoule; Appareillage d'examen des elements combustibles des piles industrielles de Marcoule

    Energy Technology Data Exchange (ETDEWEB)

    Pesenti, P; Wallet, Ph [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The authors describe a viewing and measurement cell for the slugs of Marcoule industrial reactors. This cell allows visual inspection, and photography of slugs. Length measurements are also made possible by horizontal motion of the slug both in translation and rotation. (author) [French] Les auteurs decrivent une cellule d'observation et de mesure des elements combustibles des piles industrielles de Marcoule. La cellule permet l'examen a vue, la photographie, la radioscopie et la radiographie des elements combustibles. Elle permet en outre la mesure de longueurs sur ces elements, ces derniers pouvant etre deplaces horizontalement en translation, et en rotation. (auteur)

  17. Neutronic study of the two french heavy water reactors; Etude neutronique des deux piles francaises a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    The two french reactors - the reactor of Chatillon, named Zoe, and the reactor of Saclay - P2 - were the object of detailed neutronic studies which the main ideas are exposed in this report. These studies were mostly done by the Department of the Reactor Studies (D.E.P.). We have thus studied the distribution of neutronic fluxes; the factors influencing reactivity; the link between reactivity and divergence with the formula of Nordheim; the mean time life of neutrons; neutron spectra s of P2; the xenon effect; or the effect of the different adjustments of the plates and controls bar. (M.B.) [French] Les deux reacteurs francais - la pile de Chatillon, appelee ZOE, et la pile de Saclay, designee dans la suite par P2 - ont fait l'objet d'etudes neutroniques detaillees dont les principales sont exposees dans ce rapport. Ces etudes ont ete pour la plupart effectuees dans le cadre du Departement des Etudes de Piles (D.E.P.). Nous avons ainsi entre autre etudie la distribution du flux neutronique; les facteurs influencants la reactivite; le lien entre reactivite et divergence par la formule de Nordheim; le temps de vie moyen des neutrons; les spectres de neutrons de P2; l'effet xenon; ou encore l'effet des differents reglages des plaques et barres de controles. (M.B.)

  18. Protection for work in the pressure tank of the pile G2; Protection des travaux dans le caisson de la pile G2

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J Ph; Rodier, J [Commissariat a l' Energie Atomique, Service de Protection contre les Radiations, Marcoule (France). Centre d' Etudes Nucleaires

    1961-07-01

    While the pile was shut down after a three-month run at full power, the secondary circuit was cleaned and some alterations were carried out. The pile contained 100 tons of uranium, half of which made up the periphery and was irradiated uranium. The possibility of carrying on work inside the pressure tank was not considered at the time of construction. Because of the heat and the irradiation it was only possible to remain in the pressure tank for a limited period of time, and several operators received doses of the order of 1.5 rem. Cotton clothing gave satisfactory protection against contamination and was more comfortable than the vinyl equipment. The work lasted for 17 days and involved 881 incursions into the pressure tank. (author) [French] Un nettoyage et des modifications ont ete realises dans le circuit secondaire pendant l'arret de la pile apres un fonctionnement de trois mois a pleine puissance. La pile contenait 100 tonnes d'uranium dont la moitie, composant la peripherie, etait de l'uranium irradie. La possibilite d'entreprendre un travail a l'interieur du caisson n'avait pas ete envisage lors de la construction. Le temps de sejour dans le caisson etait a la fois limite par l'irradiation et la chaleur, plusieurs operateurs, ont integre une dose de l'ordre de 1,5 rem. Les vetements de coton ont apporte une protection contre la contamination satisfaisante et un confort relatif par rapport aux equipements de vinyle. L'intervention a dure 17 jours, a comporte 881 entrees dans le caisson. (auteur)

  19. Étude de la dynamique de la pauvreté et de la dégradation des sols ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Estimation des élasticités de la demande des céréales sèches et du niébé au Niger à l'aide d'un modèle AIDS (Almost Ideal Demand System). 52095. Studies. Rôle de la migration dans les stratégies de survie ... Giving girls and women the power to decide. Addressing Africa's unmet need for family planning by intensifying ...

  20. Study and realization of an electron linear accelerator. Dynamics of accelerated electrons; Etude et realisation d'un accelerateur lineaire d'electrons. Dynamique des electrons acceleres

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-04-01

    chacune de ces relations de dispersion. La deuxieme partie de la these relative a l'etude theorique de la dynamique des electrons dans le guide permet de deduire les parametres du faisceau: etalement en phase, energie, etalement en energie des electrons et caracteristiques en charge theoriques W{sub S} = f (I{sub c}). Les resultats experimentaux relatifs aux premiers essais de l'accelerateur sont donnes et compares aux previsions theoriques. (auteur)

  1. Existence conditions of optimal trajectories in dynamic control processes; Conditions d'existence de trajectoires optimales des processus dynamiques commandes

    Energy Technology Data Exchange (ETDEWEB)

    Bonnemay-Juricek, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    The existence of solutions in the optimal control problems with free endpoints is studied in this report and existence conditions are established without the usual assumption that the control region is convex. Furthermore the results, in order to be of some utility in physical applications, are expressed only by means of conditions on the parameters defining the system. (author) [French] Ce rapport etudie l'existence de solutions optimales dans les problemes de commande ou le point terminal est libre et ou la duree de l'evolution du systeme a optimiser est connue. Des conditions d'existence y sont formulees sans recourir a l'hypothese usuelle de convexite du domaine des valeurs des commandes. De plus on a cherche a rendre utilisables les resultats en ne faisant porter les conditions que sur les parametres directement accessibles du systeme. (auteur)

  2. Rhéologie des alliages de fer pur. Lois de comportement a chaud avec recristallisation dynamique

    OpenAIRE

    Belkebir , Abdellah

    1994-01-01

    pas de résumé en anglais; Le comportement rhéologique des aciers, élabores a partir de fer de haute pureté, a été caractérisé par compression a chaud. Pour mettre en évidence l'influence individuelle ou conjointe des phénomènes de ségrégation et de précipitation, trois nuances d'acier ont été étudiées. L'influence de la vitesse et de la température de déformation sur le comportement de ces alliages a été examinée a travers les variations des paramètres rhéologiques (coefficient de sensibilité...

  3. Diversité et dynamique des communautés de protistes dans le haut Arctique canadien

    OpenAIRE

    Charvet, Sophie

    2013-01-01

    Le paysage arctique est un mélange d’étendues désertiques, fouettées par les vents, et d’une grande diversité d’écosystèmes aquatiques. Confronté à des augmentations de température nettement supérieures à la moyenne globale qui modifient les propriétés de ces paysages, l’Arctique est un site d’étude stratégique pour suivre les impacts des changements climatiques sur les communautés microbiennes endogènes. Caractéristique importante des écosystèmes arctiques, la cryosphère commence déjà à atte...

  4. In-pile experimental device for Sirene thermionic converters; Dispositif d'experimentation en pile des convertisseurs thermoioniques sirene

    Energy Technology Data Exchange (ETDEWEB)

    Bliaux, J; Durand, J; Lazare-Chopard, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The irradiation device described here, was built for in pile life tests of 100 We SIRENE converters. The nuclear converter is located in a sealed vacuum chamber, which is plugged at the lower end of a coaxial tubing acting as electrical leads. The output power is available on a variable resistive load on the bank of the reactor pool. Thermal, electrical and neutronic parameters of the converter are recorded. Since 1967, two permanent devices allowed five experiments in the swimming pool TRITON (CEN-FAR) and the results, obtained till now, are presented. (authors) [French] Le dispositif d'irradiation SIRENE decrit ici a ete concu en vue d'une etude statistique de performances de convertisseurs thermoioniques nucleaires de puissance unitaire 100 We. Le dispositif doit assurer la bonne marche du convertisseur en pile, permettre le changement de la position verticale du convertisseur dans le coeur, sortir du coeur la puissance electrique convertie sans degradation notable et enregistrer les differents parametres thermiques, electriques et neutroniques du convertisseur. Depuis 1967, deux dispositifs fonctionnent en permanence et ont permis de faire cinq experiences dans le reacteur piscine TRITON du CEN-FAR. Les resultats obtenus jusqu'a present, sont presentes. (auteurs)

  5. DYNAMIQUE DES PEUPLEMENTS DE POISSONS DANS LE RÉSERVOIR DE PETIT-SAUT (FLEUVE SINNAMARY, GUYANE FRANÇAISE.

    Directory of Open Access Journals (Sweden)

    DE MÉRONA B.

    2002-01-01

    Full Text Available La modélisation des effets des barrages hydroélectriques nécessite un grand nombre de données d’observation dans chacune des situations concrètes. En zone tropicale ces données sont souvent incomplètes et de nature hétérogène rendant difficile la comparaison entre des situations différentes. En janvier 1994, Electricité de France (EDF : Compagnie Nationale française d’Electricité a procédé à la fermeture du barrage de Petit-Saut sur le fleuve Sinnamary en Guyane française. A cette occasion, un suivi environnemental a été mené sur une période s’étendant depuis 5 années avant la fermeture jusqu’à 7 années après. En ce qui concerne les poissons, trois phases successives dans le processus de colonisation du lac ont été identifiées. Pendant la phase de mise en eau, les captures de poissons ont rapidement augmenté alors que la richesse spécifique diminuait. Une espèce dominait le peuplement. Durant les 2 années qui ont suivi, les captures se sont maintenues à un niveau élevé alors que la richesse spécifique continuait à diminuer. Le peuplement était dominé par deux espèces capables de tirer avantage des nouvelles ressources offertes par le lac. Enfin, au cours des 4 années suivantes, les captures diminuaient lentement et régulièrement et la composition spécifique se modifiait profondément. Ce schéma semble conforme à ce qui a été observé dans plusieurs grandes retenues en zone tropicale.

  6. Impact de la dynamique de peuplement sur la distribution des glossines et des trypanosomoses dans la boucle du Mouhoun (Burkina Faso*

    Directory of Open Access Journals (Sweden)

    Rouamba J.

    2009-03-01

    Full Text Available Au Burkina-Faso, la boucle du Mouhoun constitue un foyer historique des trypanosomoses humaines africaines (THA et animales africaines (TAA, transmises par les glossines. Aujourd’hui, la THA semble avoir disparu de cette région après quelques soubresauts dans les années 1970, tandis que la TAA continue de sévir. Afin de mieux comprendre ces évolutions divergentes, nous avons mené une étude géographique basée sur l’analyse de photographies aériennes entre 1952 et 2007, ainsi que d’enquêtes de terrain sur les aspects médicaux, entomologiques et vétérinaires des trypanosomoses. Il apparaît que le paysage de cette région a connu en l’espace d’un siècle des modifications intenses, notamment du fait de l’augmentation des densités de population et des surfaces cultivées, qui n’ont pas été sans conséquences sur le nombre et la distribution des mouches tsé-tsé. Associée à la lutte médicale qui avait permis la stérilisation du réservoir humain de trypanosomes dans les années 1940, cette dégradation paysagère, accompagnée du développement des aménagements hydrauliques et d’évolutions des modalités de migration des hommes et des animaux, semble pouvoir expliquer ces disparités THA/TAA. La mise en évidence de ces facteurs, et leur prise en compte lors d’études ultérieures menées dans d’autres régions, devrait permettre de délimiter des zones d’intervention prioritaires contre les trypanosomoses et leurs vecteurs dans un contexte de lutte internationale contre ces pathologies.

  7. Molecular Dynamics Simulation of Spontaneous Imbibition in Nanopores and Recovery of Asphaltenic Crude Oils Using Surfactants for EOR Applications Simulations de dynamique moléculaire d’imbibition spontanée dans des nanopores et pour la récupération d’huiles brutes asphalténiques en utilisant des agents tensioactifs pour des applications d’EOR

    Directory of Open Access Journals (Sweden)

    Stukan M.R.

    2012-12-01

    Full Text Available We present Molecular Dynamics (MD simulations of the imbibition process in nanopores in case of two different mechanisms of the wettability modification. We compare the imbibition of an aqueous surfactant solution into an oil-wet pore driven by surfactant adsorption onto the oil-wet rock surface (coating mechanism and the imbibition of an aqueous surfactants solution driven by surfactants removing the contaminant molecules from the originally water-wet surface (cleaning mechanism. Our results show qualitative difference in the imbibition dynamics in these two cases and indicate that MD simulation is a useful tool to investigate details of the imbibition mechanisms at the pore scale with direct implications for Enhanced Oil Recovery (EOR operations. Nous presentons des simulations de Dynamique Moleculaire (DM du processus d’imbibition dans des nanopores dans le cas de deux mecanismes differents de modification de mouillabilite. Nous comparons l’imbibition d’une solution aqueuse d’agent tensioactif dans un pore mouille d’huile entrainee par une adsorption d’agent tensioactif sur la surface de roche mouillee d’huile (mecanisme de revetement et l’imbibition d’une solution aqueuse d’agent tensioactif entrainee par des agents tensioactifs eliminant les molecules contaminantes de la surface originellement mouillee d’eau (mecanisme de nettoyage. Nos resultats montrent une difference qualitative en matiere de dynamique d’imbibition dans ces deux cas et indiquent que la simulation de DM constitue un outil utile pour etudier les mecanismes d’imbibition a l’echelle des pores avec des implications directes pour des operations de recuperation renforcee d’huile (EOR, Enhanced Oil Recovery.

  8. Le cadre politico-institutionnel des migrations antillaises : des dynamiques différenciées dans un contexte géopolitique segmenté

    Directory of Open Access Journals (Sweden)

    Cédric Audebert

    2008-09-01

    Full Text Available La construction historique des sociétés caribéennes est indissociable des mouvements migratoires séculaires qui les ont animées. Le cadre politico-juridique favorable aux migrations antillaises vers leur métropole rend compte de la vigueur des courants migratoires issus des territoires dépendants de la région ainsi que de leur orientation quasi-exclusive vers les métropoles. La problématique migratoire se pose en des termes différents concernant les territoires indépendants. L’analyse de trois populations caribéennes – les Portoricains, les Franco-antillais, les Haïtiens – interroge la particularité des contextes politico-institutionnels des sociétés d’origine en lien avec les modalités singulières de leur colonisation. Au regard de la remarquable diversité des statuts politiques des territoires de la Caraïbe, l’analyse du lien entre migration et fait colonial nécessite de s’interroger sur l’influence de ces derniers sur la temporalité, l’ampleur, la composition et la spatialisation des mouvements de populations.The making of Caribbean societies is indissociable from long-term migration movements. The favourable politico-legal framework of Caribbean migrations towards their metropoles accounts for the strength of migration streams from politically dependent territories in the region. It also accounts for their spatial configuration as ‘migratory couples’. The issue is different as far as independent territories are concerned. The analysis of three Caribbean populations – Puerto Ricans, French West Indians, Haitians – questions the particularity of the politico-institutional contexts of source societies in relation with the singular modalities of their colonization. Given the remarkable diversity of political statuses in the Caribbean, the analysis of the relation between migration and the colonial history requires to question the influence of these statuses on the temporality, the scale, the

  9. Applications of sub-optimality in dynamic programming to location and construction of nuclear fuel processing plant; Application de la sous-optimalite en programmation dynamique a la localisation et la cadence optimales de construction des equipements

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L; Deledicq, A [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires, section des etudes economiques generales

    1968-09-01

    First, the point of applying Dynamic Programming to optimization and Operational Research problems in chemical industries are recalled, as well as the conditions in which a dynamic program is illustrated by a sequential graph. A new algorithm for the determination of sub-optimal politics in a sequential graph is then developed. Finally, the applications of sub-optimality concept is shown when taking into account the indirect effects related to possible strategies, or in the case of stochastic choices and of problems of the siting of plants... application examples are given. (authors) [French] On rappelle d'abord l'interet de la Programmation Dynamique dans les problemes d'optimisation et de Recherche Operationnelle dans les industries chimiques, et les conditions de representation d'un programme dynamique par un graphe sequentiel. On expose ensuite un nouvel algorithme de determination de politiques sous-optimales dans un graphe sequentiel. On montre enfin les applications du concept de sous-optimalite a la prise en compte d'effets indirects lies aux politiques possibles, aux choix dans l'aleatoire, a des problemes de localisation optimale d'usines... et on donne des exemples d'utilisation. (auteurs)

  10. Etude de la dynamique en régimes quasiharmonique et anharmonique de la phase basse température de la triéthylènediamine par diffusion cohérente inélastique des neutrons

    OpenAIRE

    Hedoux , A.; Sauvajol , J.L.; More , M.

    1988-01-01

    La triéthylènediamine N(CH2CH2)3N cristallise jusqu'à Tc = 351 K dans une phase solide ordonnée de symétrie hexagonale compacte. Les expériences de diffusion cohérente inélastique des neutrons réalisées dans la phase basse température s'inscrivent dans le cadre de l'étude du processus de la transition martensitique à Tc à partir de l'évolution avec la température des paramètres dynamiques. Ainsi les courbes de dispersion ont été déterminées à 190 K, 245 K et 295 K. Les mesures effectuées à te...

  11. Some particular problems put by operating experimental reactors; Quelques problemes particuliers poses par le fonctionnement des piles laboratoires

    Energy Technology Data Exchange (ETDEWEB)

    Candiotti, C; Mabeix, R; Uguen, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    On basis of a six years experience in operating research reactors, the authors explain, first, the difference in their utilization between these piles and another similar ones and, after, in consequence, they set off corresponding servitudes. These servitudes put very particular problems in operating itself, maintenance, modifications or additions on these apparatus. (author) [French] Les redacteurs se basant sur six annees d'experience dans l'exploitation de reacteurs de recherche, exposent tout d'abord les differences d'utilisation entre ces engins et d'autres appareils fonctionnellement similaires et font ressortir, par voie de consequence, les servitudes correspondantes. Ces servitudes posent des problemes tres particuliers dans les domaines de l'exploitation proprement dite, de l'entretien, des modifications ou adjonctions apportees a l'ensemble. (auteur)

  12. Some particular problems put by operating experimental reactors; Quelques problemes particuliers poses par le fonctionnement des piles laboratoires

    Energy Technology Data Exchange (ETDEWEB)

    Candiotti, C.; Mabeix, R.; Uguen, R. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    On basis of a six years experience in operating research reactors, the authors explain, first, the difference in their utilization between these piles and another similar ones and, after, in consequence, they set off corresponding servitudes. These servitudes put very particular problems in operating itself, maintenance, modifications or additions on these apparatus. (author) [French] Les redacteurs se basant sur six annees d'experience dans l'exploitation de reacteurs de recherche, exposent tout d'abord les differences d'utilisation entre ces engins et d'autres appareils fonctionnellement similaires et font ressortir, par voie de consequence, les servitudes correspondantes. Ces servitudes posent des problemes tres particuliers dans les domaines de l'exploitation proprement dite, de l'entretien, des modifications ou adjonctions apportees a l'ensemble. (auteur)

  13. Can-rupture detection in gas-cooled nuclear reactors; La detection des ruptures de gaine dans les piles nucleaires refroidies par gaz

    Energy Technology Data Exchange (ETDEWEB)

    Roguin, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Can-rupture detection (DRG) is one important aspect of pile safety, more particularly so in the case of gas-cooled reactors. A rapid and sure detection constitutes also an improvement as far as the efficiency of electricity-producing nuclear power stations are concerned. Among the numerous can-rupture detection methods, that based on the measurement of the concentration of short-lived fission gases in the heat-carrying fluid has proved to be the most sensitive and the most rapid. A systematic study of detectors based on the electrostatic collection of the daughter products of fission gases has been undertaken with a view to equip the reactors EL 2, G 3, EDF 1, EDF 2 and EDF 3, the gas loops of PEGASE and EL 4. The different parameters are studied in detail in order to obtain a maximum sensitivity and to make it possible to construct detection devices having the maximum operational reliability and requiring the minimum maintenance. The primary applications of these devices are examined in the case of the above-mentioned reactors. (author) [French] La Detection des Ruptures de Gaines (D. R. G.) est un aspect important de la securite des piles et plus particulierement des piles refroidies par un gaz. Une detection rapide et sure constitue aussi un element d'amelioration du rendement des centrales nucleaires productrices d'energie electrique. Parmi les nombreuses methodes de detection des ruptures de gaines, la mesure de la concentration dans le fluide caloporteur des gaz de fission a vie courte s'est revelee comme la plus sensible et la plus rapide. Une etude systematique des detecteurs a collection electrostatique des descendants des gaz de fission a ete entreprise en vue d'equiper les piles EL 2, G 3, EDF 1, EDF 2 et EDF 3, les boucles a gaz de la pile Pegase et la pile EL 4. Les divers parametres sont etudies en detail pour obtenir une sensibilite maximum et permettre la realisation de dispositifs de detection ayant le maximum de securite de

  14. Can-rupture detection in gas-cooled nuclear reactors; La detection des ruptures de gaine dans les piles nucleaires refroidies par gaz

    Energy Technology Data Exchange (ETDEWEB)

    Roguin, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Can-rupture detection (DRG) is one important aspect of pile safety, more particularly so in the case of gas-cooled reactors. A rapid and sure detection constitutes also an improvement as far as the efficiency of electricity-producing nuclear power stations are concerned. Among the numerous can-rupture detection methods, that based on the measurement of the concentration of short-lived fission gases in the heat-carrying fluid has proved to be the most sensitive and the most rapid. A systematic study of detectors based on the electrostatic collection of the daughter products of fission gases has been undertaken with a view to equip the reactors EL 2, G 3, EDF 1, EDF 2 and EDF 3, the gas loops of PEGASE and EL 4. The different parameters are studied in detail in order to obtain a maximum sensitivity and to make it possible to construct detection devices having the maximum operational reliability and requiring the minimum maintenance. The primary applications of these devices are examined in the case of the above-mentioned reactors. (author) [French] La Detection des Ruptures de Gaines (D. R. G.) est un aspect important de la securite des piles et plus particulierement des piles refroidies par un gaz. Une detection rapide et sure constitue aussi un element d'amelioration du rendement des centrales nucleaires productrices d'energie electrique. Parmi les nombreuses methodes de detection des ruptures de gaines, la mesure de la concentration dans le fluide caloporteur des gaz de fission a vie courte s'est revelee comme la plus sensible et la plus rapide. Une etude systematique des detecteurs a collection electrostatique des descendants des gaz de fission a ete entreprise en vue d'equiper les piles EL 2, G 3, EDF 1, EDF 2 et EDF 3, les boucles a gaz de la pile Pegase et la pile EL 4. Les divers parametres sont etudies en detail pour obtenir une sensibilite maximum et permettre la realisation de dispositifs de detection ayant le maximum de securite de fonctionnement et le

  15. Study of superconductors with high critical temperature by using the vibrating blade technique: anelastic properties, vortices dynamics; Etude des supraconducteurs a haute temperature critique par la technique de la lame vibrante: - proprietes anelastiques, - dynamique des vortex

    Energy Technology Data Exchange (ETDEWEB)

    De Brion, Sophie

    1991-10-04

    This research thesis reports the application of the vibrating blade technique to the study of high critical temperature superconductors, first for the anelastic properties, and then for vortices dynamics. As far as the study of anelastic properties is concerned, the author reports the measurement of dissipation and of Young modulus, between 4 K and 300 K and at about 1 khz, in YbaCuO ceramics with various oxygen content. A detailed study of the tetragonal phase reveals the existence of a single relaxation process, the magnitude of which depends on the compound oxygen content and on its thermal treatment. In the second part, the author reports the measurement, under magnetic field and within a temperature range lower than the superconducting critical temperature, of a YbaCuO crystal with two different oxygen concentrations. At low temperature, the author studies the contribution of vortices trapped in an irreversible state. At high temperature, this contribution disappears and thus defines an irreversibility line beyond which vortices are in a reversible regime. This line is studied for different magnetic field orientations with respect to CuO planes. It is interpreted in terms of de-trapping thermally activated by vortices [French] La technique de la lame vibrante a ete appliquee a l'etude des supraconducteurs a haute temperature critique, pour leurs proprietes anelastiques d'abord, pour la dynamique des vortex ensuite. Dans la gamme de temperature 4 K - 300 K, nous avons mesure la dissipation et le module d'Young, a une frequence de 1 kHz environ, dans des ceramiques YBaCuO (phase 123) de differentes teneurs en oxygene (variant de O{sub 6} a O{sub 7}). Nous avons observe plusieurs pics de dissipation. Une etude detaillee de la phase tetragonale (de O{sub 6} a O{sub 6,4}) a mis en evidence un seul processus de relaxation, active thermiquement avec une energie de 0,1 eV et dont l'ampleur depend de la teneur en oxygene du compose et de son traitement thermique. Cette

  16. EVALUATION DE L’IMPACT ENVIRONNEMENTAL : Vers une compréhension de la dynamique des populations de colza « échappées » des cultures à l’échelle d’une région agricole

    Directory of Open Access Journals (Sweden)

    Pessel Fabrice-Del

    2000-07-01

    Full Text Available Dans le cadre des études de risques agro-environnementaux, comme dans celui de la mise en place de stratégies de gestion des cultures transgéniques (par exemple la segmentation des filières de production OGM/non OGM, s’il est indispensable de quantifier les différents processus d’échappement des transgènes depuis les parcelles cultivées (flux de pollen et/ou de graines, il est également nécessaire de déterminer leurs potentialités de maintien en dehors des parcelles cultivées (aptitudes écologiques des hybrides interspécifiques et/ou de la plante dans des environnements hors des parcelles cultivées. En effet, des populations, dans lesquelles seraient présents un ou plusieurs transgènes, seraient suceptibles de se comporter comme des réservoirs et/ou des relais de pollutions génétiques entre deux filières de production avec et sans OGM. À plus long terme, la connaissance des processus gouvernant la dynamique et la persistance de ces populations s’avère indispensable pour une gestion efficace des différentes situations de crise possibles (sanitaire, écologique ou agronomique, en particulier pour déterminer la durée des suivis après un arrêt éventuel des cultures transgéniques.

  17. Dynamique des orbites fortement elliptiques

    OpenAIRE

    Lion , Guillaume

    2013-01-01

    Most of the orbits of artificial satellites around the Earth have relatively low eccentricities. The calculation of their trajectories is very well under control, either by means of numerical methods when it comes to focus on accuracy and comparing observations, or either through analytical or semi-analytical theories to optimize the speed of calculations. This second category is used, in particular, for computing many long-term trajectories that could help to ensure the security and safety o...

  18. Shutdown channels and fitted interlocks in atomic reactors; Chaines de securite et verrouillages installes sur les piles atomiques

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J; Landauer, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    This catalogue consists of tables (one per reactor) giving the following information: number and type of detectors, range of the shutdown channels, nature of the associated electronics, thresholds setting off the alarms, fitted interlocks. These cards have been drawn up with a view to an examination of the reactors safety by the 'Reactor Safety Sub-Commission', they take into account the latest decisions. The reactors involved in this review are: Azur, Cabri, Castor-Pollux, Cesar-Marius-2, Edf-2, EL3, EL4, Eole, G1, G2-G3, Harmonie, Isis, Masurca, Melusine, Minerve, Osiris, Pegase, Peggy, PAT, Rapsodie, SENA, Siloe, Siloette, Triton-Nereide, and Ulysse. (authors) [French] Ce catalogue est compose d'un ensemble de tableaux (a raison de un tableau par pile) donnant les renseignements suivants: nombre et nature des detecteurs, dynamique des chaines, nature de l'electronique associee, seuils provoquant des actions de securite, verrouillages installes. Ces fiches ont ete etablies en vue de l'examen de la securite des piles par la 'Sous-Commission de Surete des Piles', et tiennent compte des decisions de celle-ci. Les reacteurs concernes sont: Azur, Cabri, Cator-Pollux, Cesar-Marius-2, Edf-2, EL3, EL4, Eole, G1, G2-G3, Harmonie, Isis, Masurca, Melusine, Minerve, Osiris, Pegase, Peggy, PAT, Rapsodie, SENA, Siloe, Siloette, Triton-Nereide, et Ulysse. (auteurs)

  19. Fuel elements for pressurised-gas reactors; Elements combustibles des piles a gaz sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Englander, M; Gauthron, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The design and fabrication of fuel elements for the first CO{sub 2} pressurized reactors have induced to investigate: various cladding materials, natural uranium base fuels, canning processes. The main analogical tests used in connection with the fuel element study are described. These various tests have enabled, among others, the fabrication of the fuel element for the EL2 reactor. Lastly, future solutions for electrical power producing reactors are foreseen. (author)Fren. [French] L'etude et la realisation d'elements combustibles pour les premieres piles a CO{sub 2} sous pression ont conduit a examiner: les divers materiaux de gaine, les combustibles a base d'uranium naturel, les modes de gainage. Les principaux essais analogiques ayant servi au cours de l'etude de la cartouche sont decrits. Ces divers essais ont notamment permis la realisation de la cartouche de la pile EL2. Enfin sont envisagees les solutions futures pour les piles productrices d'energie electrique. (auteur)

  20. Neutron distribution in the central cell and a peripheral cell of the Fontenay-aux-Roses pile; Repartition des neutrons dans la cellule centrale et une cellule peripherique de la pile de Fontenay-aux-Roses

    Energy Technology Data Exchange (ETDEWEB)

    Roullier, F [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1958-07-01

    The distribution of the neutron density has been determined in the central cell and a peripheral cell of the pile at Fontenay-aux-Roses. This measurement was carried out by the autoradiographic method with manganese detectors. The neutron density distribution in the uranium rod has already been studied. The measurement was completed by the study of the neutron density in the complete cell by means of detectors placed in the uranium and in the heavy water. (author) [French] La repartition de la densite des neutrons a ete determinee dans la cellule centrale et une cellule peripherique de la pile de Fontenay-aux-Roses. Cette mesure a ete effectuee par la methode d'autoradiographie avec des detecteurs de manganese. La repartition de la densite des neutrons dans la barre d'uranium a deja ete etudiee. La mesure a ete completee par l'etude de la densite des neutrons dans la cellule complete a l'aide de detecteurs places dans l'uranium et dans l'eau lourde. (auteur)

  1. Calculation programme for the accidental transients in reactors of the gas-graphite type; Programme de calcul des transitoires accidentels des piles de la filiere graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Henri, Ch.; Bayard, J.P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The study of the behaviour of the fuel during certain incidents or accidents in reactors is closely connected to the study of the changes in temperature. This document describes in the first part the main physical phenomena governing the kinetics of the accident. The aim is to know the temperatures at all points and at all times during the irregular regime which can follow the initial stable regime. In the second part an explanation is given of the numerical methods used. (authors) [French] L'etude du comportement du combustible lors de certains incidents ou accidents de pile est etroitement liee a l'etude de l'evolution des temperatures. Dans sa premiere partie, ce document decrit les phenomenes physiques principaux intervenant dans la cinetique de l'accident. Le but recherche est la connaissance des temperatures en tout point et a tout instant d'un regime varie, faisant suite a un regime initial stable. Dans la deuxieme partie les methodes numeriques employees sont explicitees. (auteurs)

  2. On Implementation of Dynamic Programming for Optimal Control Problems with Final State Constraints À propos de l’implémentation de la programmation dynamique pour des problèmes de contrôle optimal avec des contraintes sur l’état final

    Directory of Open Access Journals (Sweden)

    Sundström O.

    2009-09-01

    Full Text Available In this paper we present issues related to the implementation of dynamic programming for optimal control of a one-dimensional dynamic model, such as the hybrid electric vehicle energy management problem. A study on the resolution of the discretized state space emphasizes the need for careful implementation. A new method is presented to treat numerical issues appropriately. In particular, the method deals with numerical problems that arise due to high gradients in the optimal cost-to-go function. These gradients mainly occur on the border of the feasible state region. The proposed method not only enhances the accuracy of the final global optimum but also allows for a reduction of the state-space resolution with maintained accuracy. The latter substantially reduces the computational effort to calculate the global optimum. This allows for further applications of dynamic programming for hybrid electric vehicles such as extensive parameter studies. Cette publication présente certains problèmes concernant l’implémentation de la programmation dynamique pour le contrôle optimal d’un modèle dynamique scalaire, comme par exemple la gestion énergétique d’un véhicule hybride électrique. Une étude sur la résolution de l’espace d’état discrétisé souligne le besoin d’une implémentation minutieuse. Une nouvelle méthode qui permet de traiter des problèmes numériques d’une façon adéquate est présentée. Cette méthode permet particulièrement de résoudre des problèmes numériques engendrés par de forts gradients dans la fonction coût optimale. Ces gradients se situent surtout aux bornes de l’ensemble d’états atteignables. La méthode proposée améliore non seulement la précision de l’optimum global, mais permet aussi de réduire la résolution de l’espace d’état en conservant la précision. Le nombre de calculs nécessaire pour évaluer l’optimum global est ainsi considérablement réduit. Cela permet des

  3. Some aspects of in-pile swelling of fissile materials, 1. part: non-alloyed {alpha} uranium; Quelques aspects du gonflement en pile des materiaux fissiles. 1. partie: uranium {alpha} non allie

    Energy Technology Data Exchange (ETDEWEB)

    Mikailoff, H [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    An examination has been carried out of non-alloyed uranium samples, having various structural states, cold-worked and recrystallized, as-cast and {beta}-treated, and irradiated at temperatures of between 450 and 600 C and with burn-ups from 1300 to 5500 MW days/metric ton. These samples swelled because of precipitation of the fission gases the porosity thus produced has a morphology depending mainly on the type of deformation to which the metal has been subjected and which is due to in-pile growth. The most homogeneous distribution of pores, and thus that leading to the minimum swelling, is only observed in the material having a marked [010] texture in which the growth and perhaps the thermal cycling introduce little or no strain. For other materials the deformation /swelling association causes a more rapid destruction of the samples either by cracking when the deformation is due to twinning, or by pronounced swelling localized in the bands when deformation is due to slipping. Finally the fission-gas precipitation considerably facilitates, above 500 C, the germination and growth of the intergranular cracks which can then develop at low stresses. (author) [French] On a examine des echantillons d'uranium non allie, de divers etats structuraux, marteles et recristallises, bruts de coulee et traites {beta}, irradies a des temperatures comprises entre 450 et 600 C, et a des taux de combustion allant de 1300 a 5500 MWj/t. Ces echantillons ont gonfle par suite de la precipitation de gaz de fission: la porosite ainsi fournie a une morphologie qui depend principalement des modes de deformation subie par le metal et due a la croissance en pile. La repartition la plus homogene des pores, donc celle qui donnera le gonflement minimum, est observee seulement dans le materiau a forte texture [010] dans lequel la croissance et eventuellement le cyclage thermique introduisent peu ou pas de contraintes. Dans les autres materiaux l'association deformation/gonflement rend plus rapide

  4. The Sprint/1 language for the dynamic evaluation of the mathematic formulas by direct communication with a computer; Le langage Sprint/1 pour l'evaluation dynamique des formules mathematiques par dialogue direct avec un ordinateur

    Energy Technology Data Exchange (ETDEWEB)

    Cavadia, I C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires, direction des piles atomiques, direction du CEN-Saclay

    1968-06-01

    facilement des structures complexes en partant des expressions tres simples. Ainsi il peut faire une etude globale du comportement d'un processus dynamique d'apprentissage de la machine ce qui constitue une des caracteristiques de l'intelligence artificielle. (auteur)

  5. Des communautés microbiennes au service de la qualité des fromages : diversité et dynamique adaptative et fonctionnelle des populations endogènes et ensemencées

    OpenAIRE

    Delbes, Céline; Monnet, Christophe; Irlinger, Francoise

    2015-01-01

    Les fromages traditionnels hébergent un microbiote diversifié, composé de populations microbiennes endogènes et de ferments, qui joue un rôle majeur dans le développement des qualités sanitaires et sensorielles du produit fini. La connaissance de la diversité microbienne taxonomique et fonctionnelle des produits laitiers s’enrichit depuis ces trois dernières années des apports des approches (méta)génomiques. Plus de 100 genres et 400 espèces microbiennes ont été détectés dans le lait cru et l...

  6. Simulation of power excursions - Osiris reactor; Simulation des excursions de puissance - pile Osiris

    Energy Technology Data Exchange (ETDEWEB)

    Pascouet, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Following the experimental work accomplished in the U.S.A. on Borax 1 and SPERT 1 and the accident of SL 1, the 'Commissariat a l'Energie Atomique' started a research program about the safety of its own swimming Pool reactors, with regard to power excursions. The first research work led to the design of programmed explosive charges, adapted to the simulation of a power excursion. This report describes the application of these methods to the investigation of Osiris safety. (author) [French] A la suite des essais effectues aux U.S.A. sur BORAX 1 et SPERT 1 et de l'accident survenu a SL 1, le Commissariat a l'Energie Atomique a lance un programme d'etudes sur la surete de ses reacteurs piscines vis-a-vis des excursions de puissance. Les premieres etudes ont abouti A la mise au point de charges programmees capables de simuler une excursion de puissance. On trouvera dans le present rapport l'application de ces methodes a l'etude de la surete d'OSIRIS. (auteur)

  7. A study of some radioprotection apparatuses used in the case of pool reactors; Etude de quelques dispositifs de radioprotection en service aupres des piles piscines

    Energy Technology Data Exchange (ETDEWEB)

    Robien, E de; Choudens, H de; Delpuech, J [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-07-01

    Various problems of radioprotection concerning swimming-pool reactors in Grenoble have led us to study adequate solutions: a) The automatic verification of the staff-radioactivity when coming out of Melusine or Siloe has been realized thanks to a {beta}{gamma} gate which is insensitive to the ambient background in the reactor-hall; b) The automatic verification of the contamination of the shoes of the agents working in these reactors has been realized with a dedicated device; c) The necessity to measure precisely {gamma} doses with the help of an autonomous apparatus has led to the making of a plastic-scintillator {gamma} dosimeter; d) The obligation to forbid the opening of doors in some places where there might be a great intensity of radiation, has led us to make doors open according to the intensity of radiation inside the rooms; e) The releases of radioactive iodine have been measured with activated charcoal cartridges that surround a scintillator connected with a unique channel selector; f) Finally the control of reactor safety rod fall in case of a radioactive accident has been secured by a chain whose detector is a chamber immersed in the swimming-pool, which offers, in the particular case of the hot thickness swimming-pool reactor a double advantage: first it enables us to regulate the upper hot water layer, second to get free of transitory radiations which appear in the reactor hall as the experimental apparatuses are taken out from the core. (authors) [French] Differents problemes de radioprotection se posant aupres des piles piscines de Grenoble, ils ont necessite l'etude de solutions particulieres: a) le controle automatique de la radioactivite du personnel sortant de Melusine ou de Siloe a ete realise a l'aide d'un portique {beta}{gamma} insensible au bruit de fond ambiant du hall des piles; b) le controle automatique de la contamination des souliers des agents travaillant dans ces piles a ete realise par une passerelle pieds {beta}{gamma}; c) la

  8. Crystal Dynamics from Neutron Spectrometry; Etude de la dynamique des cristaux par la spectrometrie neutronique; Izuchenie voprosov dinamiki kristallov metodami nejtronnoj spektrometrii; Estudio de la dinamica de redes cristalinas por espectrometria neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Woods, A. D.B. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1963-01-15

    This paper reviews investigations carried out at Chalk River on the lattice dynamics of various crystals including lead, sodium, alkali halides, semi-conductors, and other more complex compounds. Analysis of the low temperature results (-{approx}100{sup o}K) gives considerable insight into the nature of the interatomic forces. In sodium, a simple metal, the interatomic forces are very nearly derivable from a potential. Lead, a more complicated metal, has extremely long range forces accompanied by strong electronic effects. At higher temperatures anharmonic effects are very pronounced in both metals, especially in lead. The alkali halide results can be interpreted on a ''shell'' model, with polarizable ions. Even at low temperature neutron groups corresponding to the longitudinal optical modes. (author) [French] Dans ce memoire, l'auteur decrit les recherches faites a Chalk River sur la dynamique des reseaux de certains cristaux, y compris le plomb, le sodium, les halogenures alcalins, les semi-conducteurs et d'autres composes complexes. L'analyse des resultats obtenus a basse temperature (environ 100{sup o}K) fournit de nombreux renseignements sur la nature des forces interatomiques. Dans le sodium (metal simple), les forces interatomiques peuvent presque etre derivees d'un potentiel. Dans un metal plus complique, tel que le plomb, on trouve des forces ayant une portee extremement grande et comportant des effets electroniques marques. A des temperatures plus elevees, il se produit des effets anharmoniques tres prononces dans les deux metaux et particulierement dans le plomb. On peut interpreter les resultats obtenus pour les halogenures alcalins en se fondant sur le modele en couche comportant des ions polarisables. Meme aux basses temperatures, les groupes de neutrons correspondant aux modes optiques longitudinaux possedent des largeurs dependant de la temperature, que l'on ne comprend pas encore parfaitement. (author) [Spanish] Los autores pasan revista a las

  9. Swimming-pool piles; Piles piscines

    Energy Technology Data Exchange (ETDEWEB)

    Trioulaire, M [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    In France two swimming-pool piles, Melusine and Triton, have just been set in operation. The swimming-pool pile is the ideal research tool for neutron fluxes of the order of 10{sup 13}. This type of pile can be of immediate interest to many research centres, but its cost must be reduced and a break with tradition should be observed in its design. It would be an advantage: - to bury the swimming-pool; - to reject the experimental channel; - to concentrate the cooling circuit in the swimming-pool; - to carry out all manipulations in the water; - to double the core. (author) [French] En France, deux piles piscines, Melusine et Triton, viennent d'entrer en service. La pile piscine est l'outil de recherche ideal pour des flux de neutrons de l'ordre de 10{sup 13}. Ce type de pile peut interesser des maintenant de nombreux centres de recherches mais il faut reduire son prix de revient et rompre avec le conformisme de sa conception. Il y a avantage: - a enterrer la piscine; - a supprimer les canaux experimentaux; - a concentrer le circuit de refrigeration dans la piscine; - a effectuer toutes les manipulations dans l'eau; - a doubler le coeur. (auteur)

  10. Existence conditions of optimal trajectories in dynamic control processes; Conditions d'existence de trajectoires optimales des processus dynamiques commandes

    Energy Technology Data Exchange (ETDEWEB)

    Bonnemay-Juricek, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    The existence of solutions in the optimal control problems with free endpoints is studied in this report and existence conditions are established without the usual assumption that the control region is convex. Furthermore the results, in order to be of some utility in physical applications, are expressed only by means of conditions on the parameters defining the system. (author) [French] Ce rapport etudie l'existence de solutions optimales dans les problemes de commande ou le point terminal est libre et ou la duree de l'evolution du systeme a optimiser est connue. Des conditions d'existence y sont formulees sans recourir a l'hypothese usuelle de convexite du domaine des valeurs des commandes. De plus on a cherche a rendre utilisables les resultats en ne faisant porter les conditions que sur les parametres directement accessibles du systeme. (auteur)

  11. Dosimetry techniques of thermal neutrons and {gamma} radiation in reactor cores; Techniques de dosimetrie des neutrons thermiques et du rayonnement {gamma} dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, J; Draganic, I; Hering, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Chemical studies under radiation done in the reactor cores require to be followed by dosimetry. When the irradiations are done in the reflector, one can limit to the measure of the {gamma} and the neutron radiation. For the dosimetry of the {gamma} radiation, a dosimeter of ferrous sulfate is convenient until doses of about 10{sup 6} rep. The use of aired oxalic acid solutions permits to reach 10{sup 7} rep. The dosimetry of thermal neutrons has been made with solutions of cobalt sulphate or paper filter impregnated with this salt. The total chemical effect of the {gamma} and of the slow neutrons radiation is obtained with solutions of ferrous sulfate added with lithium sulphate. (M.B.) [French] Les etudes de chimie sous radiation faites dans les piles exigent d'etre suivies par dosimetrie. Lorsque les irradiations sont effectues dans le reflecteur, on peut se limiter a doser le rayonnement {gamma} et les neutrons. Pour la dosimetrie du rayonnement {gamma}, un dosimetre a sulfate ferreux convient jusqu'a des doses d'environ 10{sup 6} rep. L'emploi de solutions aerees d'acide oxalique permet d'atteindre 10{sup 7} rep. La dosimetrie des neutrons thermiques a ete faite avec des solutions de sulfate de cotalt ou du papier filtre impregne de ce sel. L'effet chimique total du rayonnement {gamma} et des neutrons lents est obtenu avec des solutions de sulfate ferreux additionne de sulfate de lithium. (M.B.)

  12. Neutron spin echo spectroscopy. Its application to the study of the dynamics of polymers in solution; La spectrometrie par echos de spins de neutrons. Application a l'etude de la dynamique des polymeres en solution

    Energy Technology Data Exchange (ETDEWEB)

    Papoular, Robert

    1992-06-15

    : ses caracteristiques et ses performances, ainsi que les premiers resultats physiques que nous avons obtenus a l'aide de MESS. En particulier, ce memoire inclut deux articles montrant comment la depolarisation des neutrons, la rotation des spins et les echos de spins peuvent etre utilises pour etudier les supraconducteurs de haut-Tc. La derniere partie traite de la dynamique des systemes ternaires Polymere-Polymere-Solvant et montre comment l'utilisation conjointe des echos de spins de neutrons et des methodes de variation de contraste font des Echos de Spins de Neutrons un outil privilegie pour de telles etudes physico-chimiques, et cela grace aux gammes de temps et de vecteurs de diffusion accessibles par cette technique. Enfin, le cas specifique du polydimethylsiloxane partiellement deuterie en solution semi-diluee dans le toluene est decrit. Nous avons mis en evidence experimentalement et separement les modes diffusifs cooperatif et interdiffusif predits par la theorie de Akcasu, Benoit Benmouna et al. Ces resultats, obtenus au L.L.B. (Saclay), font l'objet du dernier article de cette these. (auteur)

  13. The development of an electrically compensated differential calorimeter for the measurement of in-pile heat evolution (1962); Etude et realisation d'un calorimetre differentiel a compensation electrique pour la mesure des echaufpements en pile (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Ayela, F; Derrien, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    It has been possible with the calorimeter of which we give the principle and details in the present report, to determine the calorific power produced by nuclear radiation in a given sample using simple electrical measurement. It also renders unnecessary all absolute measurements of temperature, all possible calibration, and the use of the thermal or thermoelectric constants of the constituent elements. The possible uses of the apparatus are fairly varied, as shown by the first in-pile experiments which we have carried out and for which we give results. (authors) [French] Le calorimetre, dont nous decrivons le principe et les details dans le present rapport, nous permet de determiner, par de simples mesures electriques, la puissance calorifique liberee par les rayonnements nucleaires dans un echantillon donne. Il nous affranchit aussi, de toute mesure absolue de temperature, de tout etalonnage prealable, et de l'utilisation des constantes thermiques ou thermoelectriques de ses elements constitutifs. Les possibilites d'emploi de l'appareil sont assez variees comme nous le montrent les premiers essais que nous avons effectues en pile et dont nous donnons les resultats. (auteurs)

  14. Dynamique de croissance et taux de mortalité de Rhizophora spp ...

    African Journals Online (AJOL)

    SARAH

    30 janv. 2015 ... Dynamique des paysages végétaux du littoral centre-ouest du Gabon autour de. Port-Gentil : Approche spatiale et analyse des données de terrain. Thèse de doctorat. Univ. Paul-Valery Montpellier 3, France. 302 p. Spalding MD, Blasco F, Field CD, 1997. World. Mangrove Atlas. ISME, Okinawa, Japan. 251.

  15. Etude par émission acoustique de la dynamique des dislocations pendant la déformation cyclique de polycristaux d'aluminium

    Science.gov (United States)

    Slimani, A.; Fleischmann, P.; Fougères, R.

    1992-06-01

    The cyclic plasticity of 5N polycrystalline aluminium have been studied at room temperature by measuring the continuous acoustic emission (A.E.) due to dislocations movements in the metal. In this study, original data have been obtained in the understanding of continuous A.E. sources. In comparison with classical interpretation given in the literature, the fact that dislocations are arranged according to a dislocation cell structure from the first cycle has been included in the analysis of the results. From this, it has been shown that the amplitude of the A.E. signal is not directly connected with the plastic strain rate prescribed to the fatigue sample and that the probability density function of dislocation loops created during the cycling can be determined. La plasticité cyclique de l'AI 5N polycristallin a été étudiée à la température ambiante à partir de mesures d'émission acoustique continue (E.A.). L'application de la technique de l'E.A. nous a permis d'obtenir des données originales quant aux mécanismes sources d'E.A. Par rapport aux interprétations classiques de la littérature, nous avons fait intervenir le fait que, dès les premiers cycles, une structure cellulaire de dislocations est établie. Nous montrons que l'amplitude du signal d'E.A. n'est plus liée directement à la vitesse de déformation plastique macroscopique. A partir de cette donnée, l'analyse des résultats d'E.A. permet d'obtenir des informations sur la fonction distribution des boucles de dislocations créées au cours de la déformation cyclique.

  16. Radio-active pollution near natural uranium-graphite-gas reactors; La pollution radioactive aupres des piles uranium naturel - graphite - gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.; Pouthier, J.; Delmar, J. [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1967-07-01

    The results of numerous evaluations of the contamination are given: - Reactors in operation during maintenance operations. - Reactors shut-down during typical repair operations (coolants, exchangers, interior of the vessel, etc. ) - Following incidents on the cooling circuit and can-rupture. They show that, except in particular cases, it is the activation products which dominate. Furthermore, after ten years operation, the points at which contamination liable to emit strong doses accumulates are very localized and the individual protective equipment has not had to be reinforced. (authors) [French] Les resultats de nombreuses evaluations de la contamination sont donnes: - Piles en marche pendant les operations d'entretien - Piles a l'arret au cours des chantiers caracteristiques (refrigerants, echangeurs, interieur du caisson, etc.) - A la suite d'incidents sur le circuit de refroidissement et de rupture de gaine. Ils montrent que, sauf cas particulier, ce sont essentiellement les produits d'activation qui dominent. Par ailleurs apres 10 ans de fonctionnement, les points d'accumulation de la contamination susceptibles de delivrer des debits de dose importants restent tres localises et les moyens de protection individuels utilises n'ont pas du etre renforces. (auteurs)

  17. Radio-active pollution near natural uranium-graphite-gas reactors; La pollution radioactive aupres des piles uranium naturel - graphite - gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J; Pouthier, J; Delmar, J [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1967-07-01

    The results of numerous evaluations of the contamination are given: - Reactors in operation during maintenance operations. - Reactors shut-down during typical repair operations (coolants, exchangers, interior of the vessel, etc. ) - Following incidents on the cooling circuit and can-rupture. They show that, except in particular cases, it is the activation products which dominate. Furthermore, after ten years operation, the points at which contamination liable to emit strong doses accumulates are very localized and the individual protective equipment has not had to be reinforced. (authors) [French] Les resultats de nombreuses evaluations de la contamination sont donnes: - Piles en marche pendant les operations d'entretien - Piles a l'arret au cours des chantiers caracteristiques (refrigerants, echangeurs, interieur du caisson, etc.) - A la suite d'incidents sur le circuit de refroidissement et de rupture de gaine. Ils montrent que, sauf cas particulier, ce sont essentiellement les produits d'activation qui dominent. Par ailleurs apres 10 ans de fonctionnement, les points d'accumulation de la contamination susceptibles de delivrer des debits de dose importants restent tres localises et les moyens de protection individuels utilises n'ont pas du etre renforces. (auteurs)

  18. Fluid Dynamics Problems of Vehicles Operating Near or in the Air-Sea Interface (Problemes de Dynamique des Fluides des Vehicules Evoluant dans ou pres de L’interface Air-Mer).

    Science.gov (United States)

    1999-02-01

    traitement du signal fournit effectivement un effort nul. La pression initiale dans la fosse pi est mesuree par un capteur statique eau - eau . Pour...est de plusieurs minutes en presence d’ecoulement et avec une interface air- eau de grande surface. L’hypothese principale du modele elementaire...fonction des parametres de similitude. A l’aide d’un traitement d’images on peut extraire des visualisations le contour exterieur des bulles et en

  19. Measurement of the temperature of the neutrons in reactor G1; Mesure de la temperature des neutrons dans la pile G1

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V; Sautiez, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    A precise experimental method has been adapted to the analysis of the spectrum of neutrons in the thermal region. This method uses the technique of modulation applied to a beam of neutrons issuing from a characteristic point in the pile. The analysis of the spectrum is made by adjusting, by the method of least squares, an analytical form to the experimental results. In this report are given the results obtained with a beam from the centre of the moderator of G1. The spectrum of this beam essentially represents the spectrum of the neutrons in the moderator. The most probable velocity was determined by means of Maxwell's functions. The measurements were made of different moderator temperatures between 304 deg. K and 435 deg. K. (author) [French] Une methode experimentale precise a ete mise au point pour l'analyse du spectre des neutrons dans le domaine thermique. Cette methode utilise la technique de la modulation appliquee a un faisceau de neutrons issu d'un point caracteristique de la pile. L'analyse du spectre est faite en ajustant par la methode des moindres carres une forme analytique aux resultats experimentaux. Dans ce rapport, on donne les resultats obtenus sur un faisceau du centre du moderateur de G1. Le spectre de ce faisceau represente convenablement le spectre des neutrons dans le moderateur. On s'est limite ici a une fonction de Maxwell dont on a recherche la vitesse la plus probable. Les mesures ont ete faites avec une temperature du moderateur variant entre 304 deg. K et 435 deg. K. (auteur)

  20. Reactor AQUILON. The hardening of neutron spectrum in natural uranium rods, with a computation of epithermal fissions (1961); Pile AQUILON. Durcissement du spectre des neutrons dans les barreaux d'uranium et calcul des fissions epithermiques (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Durand -Smet, R; Lourme, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    - Microscopic flux measurements in reactor Aquilon have allowed to investigate the thermal and epithermal flux distribution in natural uranium rods, then to obtain the neutron spectrum variations in uranium, Wescott '{beta}' term of the average spectrum in the rod, and the ratio of epithermal to therma fissions. A new definition for the infinite multiplication factor is proposed in annex, which takes into account epithermal parameters. (authors) [French] - Un certain nombre de mesures effectuees dans la pile Aquilon ont permis d'etablir la distribution fine des flux thermique et epithermique dans les barreaux d'uranium, et d'en deduire les variations du spectre des neutrons dans l'uranium, le terme {beta} du spectre de Wescott moyen dans le barreau et le nombre de fissions epithermiques. En annexe, il est propose une definition nouvelle du coefficient de multiplication infini, qui fait intervenir les parametres epithermiques. (auteurs)

  1. Ancrage dynamique: principales applications Dynamic Positioning: Main Applications

    Directory of Open Access Journals (Sweden)

    Fay H.

    2006-11-01

    Full Text Available L'ancrage dynamique est la technique qui a permis à la recherche pétrolière d'étendre ses possibilités bien au-delà des plateaux continentaux, sans limitation de profondeur, pour des opérations difficiles, ou encore dans un environnement océanométéorologique sévère, comme celui de la mer du Nord et des mers froides avec la présence d'icebergs. Cet article correspond à des extraits de l'ouvrage Ancrage dynamique. Technique et applications , à paraître aux Editions Technip. Après un bref rappel historique et un exposé succinct des caractéristiques des systèmes d'ancrage dynamique, les principales réalisations de navires et de plates-formes semi-submersibles équipées d'un ancrage dynamique sont présentées. La précision du maintien en position, ainsi que les limites opérationnelles des supports considérés sont de même exposées. Enfin la conclusion retrace les avantages de ce procédé, dont l'exceptionnel développement s'applique aussi aux domaines scientifiques et militaires, ainsi qu'à d'autres secteurs industriels que celui des hydrocarbures. Dynamic positioning is the technique that has enabled oil exploration to extend its possibilities far beyond continental shelves, without any limitation of water depth, for difficult operations or else in harsh environments such as for the North Sea and arctic zones with the presence of icebergs. This paper consists of extracts from the book Dynamic Positioning. Technique and Applications , to be published by Editions Technip. After a brief historical review and a succinct survey of the characteristics of dynamic positioning systems, the principal realizations of ships and semi-submersible platforms equipped with a dynamic positioning system are described. The accuracy of position holding capability as well as the operational limits of the supports considered are also described. The conclusion reviews the advantages of this technique, whose exceptional development also

  2. Persistent Memory Effects and the Mid- and Post-Brick Dynamic Behaviour of Three-Way Automotive Catalysts Effets mémoires persistants et comportement dynamique des briques médiane et postérieure de catalyseurs automobiles à trois voies

    Directory of Open Access Journals (Sweden)

    Peyton Jones J.C.

    2011-09-01

    Full Text Available This paper presents the results of an experimental study into the dynamic behaviour of a three-way automotive catalyst and its associated exhaust gas oxygen sensors. Motivated by issues of feedback sensor location, the study seeks to overlay the results of repeat experiments, with sensors and fast-response gas analyzers positioned at different locations, in order to obtain a detailed picture of system dynamics at different points within the catalyst. Initial results demonstrated that the dynamic response of the catalyst can be significantly affected by a persistent memory effect in addition to reversible deactivation dynamics and the familiar oxygen storage/release dynamics of the system. In particular, the effects of prior rich or stoichiometric operation are shown to persist even after extended periods of lean operation. This memory effect is important, not only because of its potential impact on conversion efficiency, but also because of its impact on the repeatability of experiments carried out under what would appear to be near-identical operating conditions. By pre-conditioning under rich conditions highly repeatable experiments were achieved. The results were combined to give a detailed picture of catalyst dynamics at pre-, mid- and post-catalyst locations, and provide insight into catalyst and (non-ideal exhaust gas oxygen sensor behavior. Cet article présente les résultats d’une étude expérimentale en matière de comportement dynamique d’un catalyseur automobile à trois voies et de ses capteurs d’oxygène de gaz d’échappement associés. Motivée par les problèmes de localisation des capteurs de retour d’information, l’étude cherche à corréler les résultats d’expériences répétées, capteurs et analyseurs de gaz à réponse rapide étant disposés en des emplacements différents afin d’obtenir une image détaillée des dynamiques de système en différents points à l’intérieur du catalyseur. Les r

  3. Rapport d’étape – Le Système canadien hospitalier d’information et de recherche en prévention des traumatismes : un système de surveillance des blessures dynamique et novateur

    Directory of Open Access Journals (Sweden)

    J. Crain

    2016-01-01

    Full Text Available Ce rapport d’étape sur le Système canadien hospitalier d’information et de recherche en prévention des traumatismes (SCHIRPT, un système de surveillance des blessures et des empoisonnements utilisé par les services d’urgence, décrit le résultat de la migration d’un processus d’entrée et de codage des données centralisé vers le processus décentralisé de l’eSCHIRPT, réalisée en 2011. Ce système sécurisé accroît la souplesse et la rapidité globales du SCHIRPT, attributs clés d’un système de surveillance efficace. La plate-forme intégrée de l’eSCHIRPT permet une entrée de données et un accès aux données en temps quasi réel, comprend des outils conviviaux de gestion et d’analyse des données et facilite la communication et la connectivité au sein du réseau du SCHIRPT grâce à un centre de collaboration en ligne. L’essai pilote mené actuellement sur les outils automatisés de contrôle de données et d’analyse des tendances – destinés à surveiller et à mettre en évidence les données d’entrée à partir de critères prédéfinis (par exemple un nouveau produit de consommation – révèle le potentiel de détection rapide des nouveaux dangers, enjeux et tendances que possède l’eSCHIRPT.

  4. Formulation of the energetic spectral distribution of in pile neutron flux (energies greater than a few hundred electron volts) (1963); Formulation des repartitions spectrales energetiques de flux neutroniques en pile (energies superieures a quelques centaines d'electrons-volts) (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Genthon, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    In the present report an expression is deduced for the spectral distribution of flux of over a few hundred electron volts; it is valid for most cases of thermal neutron reactors. This expression is: {psi}(E) = K [{psi}{sub o}(E) + h {psi}{sub e}(E)] {psi}{sub o}(E) is the so-called 'homogeneous' constituent of the flux; it corresponds approximately to the case of an infinite homogeneous medium; it is of the type: Y(V - E) e{sup (b{radical}}{sup E)}/E + Y(E-V) F E{sup {upsilon}} e{sup -{beta}}{sup E} The parameters V and F are such that {psi}{sub o}(E) and its derivative are continuous at the junction energy V. {psi}{sub e}(E) is the 'heterogeneous' constituent of the flux; it is of the type: E{sup {upsilon}} e{sup -{beta}}{sup E}. The various parameters of {psi}(E) are on the one hand characteristic of the nature of the reactor moderator, and on the other hand determined by a resonant flux measurement and one, or possibly two, measurements using a fast neutron threshold detector. We have been led furthermore to define an expression for the threshold reaction section which is more exact than the conventional transition function. (author) [French] Il est etabli, dans le present rapport, une formulation {psi}(E) des repartitions spectrales de flux au-dessus de quelques centaines d'electron-s volts, valable dans la majeure partie des cas de piles dites a neutrons thermiques. Cette formulation s'exprime: {psi}(E) = K [{psi}{sub o}(E) + h {psi}{sub e}(E)] {psi}{sub o}(E) est la composante dite 'homogene' du flux; elle correspond a peu pres au cas d'un milieu infini homogene; elle est du type: Y(V - E) e{sup (b{radical}}{sup E)}/E + Y(E-V) F E{sup {upsilon}} e{sup -{beta}}{sup E} les parametres V et F sont tels que {psi}{sub o}(E) et sa derivee soient continues a l'energie de jonction V. {psi}{sub e} est la composante dite 'heterogene' du flux ; elle est du type: E{sup {upsilon}} e{sup -{beta}}{sup E}. Les differents parametres de {psi}(E) sont, d'une part

  5. Big Pile or Small Pile?

    Science.gov (United States)

    Branca, Mario; Quidacciolu, Rossana G.; Soletta, Isabella

    2013-01-01

    The construction of a voltaic pile (battery) is a simple laboratory activity that commemorates the invention of this important device and is of great help in teaching physics. The voltaic pile is often seen as a scientific toy, with the "pile" being constructed from fruit. These toys use some strips of copper and zinc inserted in a piece…

  6. Application of the pulsed neutron technique on the reactors ALIZE - AQUILON (1963); Application de la methode des neutrons pulses sur les piles ALIZE et AQUILON (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Jacquemart, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    Different methods of measuring the ratio effective delayed fraction / prompt neutron lifetime, {alpha}{sub c}, are described. According to the classic pulsed neutron technique the negative reactivity due to a localized absorber is given by {rho} / {beta}{sub eff} = {alpha} / {alpha}{sub c} -1 Experiments are reported which show that in this case {alpha}{sub c} can not be considered constant for large reactivities. The absorber element distorts the flux in the system, increasing the importance of the reflector. An application of the pulsed neutron method to the measurement of critical distributed boron concentrations of various absorber elements is described. Less time is required than for the usual super-critical techniques, and the experimental analysis is simplified. It is interesting to note that the results are not influenced by the spectral sensitivity of the control element. A modified pulsed neutron method has been tried out. This procedure was used to determine by measurements at sub-critical the critical water level of uranium-heavy water lattices with a high precision. (author) [French] Differents modes operatoires pour definir la valeur du rapport pourcentage effectif de neutrons retardes / temps de vie, {alpha}{sub c}, sont exposes. La methode classique par neutrons pulses definit l'anti-reactivite d'un element absorbant a partir de la relation: {rho} / {beta}{sub eff} {alpha} / {alpha}{sub c} -1 Les manipulations effectuees montrent qu'on ne peut considerer dans ce cas {alpha}{sub c} constant pour de tres grandes anti-reactivites. L'absorbant introduit dans la pile deforme le flux et augmente l'importance du reflecteur. Une application de la methode des neutrons pulses pour mesurer le titre critique en mg de B/l de divers absorbants est signalee. Les operations sont effectuees en regime sous-critique avec un certain gain de temps et une grande facilite de depouillement. Il est interessant de noter que les resultats ne sont pas

  7. Application of the pulsed neutron technique on the reactors ALIZE - AQUILON (1963); Application de la methode des neutrons pulses sur les piles ALIZE et AQUILON (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Jacquemart, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    Different methods of measuring the ratio effective delayed fraction / prompt neutron lifetime, {alpha}{sub c}, are described. According to the classic pulsed neutron technique the negative reactivity due to a localized absorber is given by {rho} / {beta}{sub eff} = {alpha} / {alpha}{sub c} -1 Experiments are reported which show that in this case {alpha}{sub c} can not be considered constant for large reactivities. The absorber element distorts the flux in the system, increasing the importance of the reflector. An application of the pulsed neutron method to the measurement of critical distributed boron concentrations of various absorber elements is described. Less time is required than for the usual super-critical techniques, and the experimental analysis is simplified. It is interesting to note that the results are not influenced by the spectral sensitivity of the control element. A modified pulsed neutron method has been tried out. This procedure was used to determine by measurements at sub-critical the critical water level of uranium-heavy water lattices with a high precision. (author) [French] Differents modes operatoires pour definir la valeur du rapport pourcentage effectif de neutrons retardes / temps de vie, {alpha}{sub c}, sont exposes. La methode classique par neutrons pulses definit l'anti-reactivite d'un element absorbant a partir de la relation: {rho} / {beta}{sub eff} {alpha} / {alpha}{sub c} -1 Les manipulations effectuees montrent qu'on ne peut considerer dans ce cas {alpha}{sub c} constant pour de tres grandes anti-reactivites. L'absorbant introduit dans la pile deforme le flux et augmente l'importance du reflecteur. Une application de la methode des neutrons pulses pour mesurer le titre critique en mg de B/l de divers absorbants est signalee. Les operations sont effectuees en regime sous-critique avec un certain gain de temps et une grande facilite de depouillement. Il est interessant de noter que les resultats ne sont pas affectes par la

  8. Pile Driving

    Science.gov (United States)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  9. Experimental apparatus for in-pile studies of: creep of nuclear fuels, and Young's-modulus of structural materials; Dispositifs experimentaux pour etudes en pile du fluage des materiaux combustibles, et du module d'elasticite des materiaux de structure

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, A; Le Bret, P; Alfille, L; Pesenti, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Creep test under compression: the apparatus described allows to study, in an horizontal beam hole of a research reactor such as EL2, the creep behaviour of nuclear fuel samples under neutron flux. The maximum stress applied on the specimens is a constant compression chooses between 0.200 and 0.400 kg/mm{sup 2} (285 psi and 570 psi). - Young's Modulus measurement: in another horizontal beam hole of such a reactor, an apparatus allows to study the irradiation effect on Young's Modulus of a structural material specimen. (author)Fren. [French] Essai de fluage en compression: l'appareillage decrit permet d'etudier, dans un canal horizontal d'une pile experimentale type EL2, le fluage en compression d'eprouvettes de materiaux fissiles sous le flux de neutrons, sous une contrainte maximum de 500 g/mm{sup 2}. - Mesure du module d'Young: dans un canal identique au precedent, un appareillage permet de suivre l'influence du rayonnement sur le module d'elasticite d'une eprouvette d'un materiau de structure. (auteur)

  10. Dynamique spatio-temporelle de la forêt tropicale

    Science.gov (United States)

    Chave, J.

    Spatio-temporal dynamics of the tropical rain forest Mechanisms which drive the dynamics of forest ecosystems are complex, from seedling establishment to pollination, and seed dispersal by animals, running water or wind. These processes are more complex when the ecosystem shelters a large number of species and of vegetative forms, as it is the case in the tropical rainforest. To take them into account, we must develop and use models. I present a review of the fundamental mechanisms for the of a natural forest dynamics — photosynthesis, tree growth, recruitment and mortality — as well as a description of the past and of the present of tropical rainforests. This information is used to develop a spatially-explicit and individual-based forest model. Simplified models are deduced from it, and they serve to address more specific issues, such as the resilience of the forest to climate disturbances, or savanna-forest dynamics. The last topic is related to the spatio-temporal description of tropical plant biodiversity. A detailed introduction to the problem is provided, and models accounting for the maintenance of diversity are compared. These models include non spatial as well a spatial approaches (branching anihilating random walks and voter model with mutation). Les mécanismes régissant la dynamique des écosystèmes forestiers sont complexes, de l'établissement des plantules à la pollinisation et la dispersion des graines, transportées par les animaux, l'eau ou le vent. Ces processus sont d'autant plus divers que l'écosystème abrite un large nombre d'espèces et de formes végétatives, comme c'est le cas dans les forêts tropicales humides. Leur prise en compte et la compréhension de leur importance relative doit passer par la définition de modèles. Je présente une revue des différents mécanismes fondamentaux dans la dynamique d'une forêt—photosynthèse, croissance des arbres, reproduction, mortalité—ainsi qu'une description du passé et de l

  11. OSIRIS reactor radioprotection, radioprotection measurements performed during the power rise and the first 50 megawatt operation; Radioprotection de la pile OSIRIS, mesures de radioprotection effectuees au cours de la montee en puissance et des premiers fonctionnements a 50 megawatts

    Energy Technology Data Exchange (ETDEWEB)

    Fanton, B.; Lebouleux, P

    1967-12-01

    The authors supply the results of the measurements that have been made near the Osiris reactor during the power increase and during the first functioning at 50 megawatts. The measurements relate to the absorbed dose rates in the premises, the water activation and the atmospheric contamination. The influence of the heat layer of water movements and the water rate in the core chimney on the absorbed dose rate at the footbridge level overhanging the pile core has been studied. The modifications to the protection devices that have been proposed after the measurements and the effect of these modifications on the results of the measures are given then. The regeneration process of a water purification chain has been examined from the radiation protection point of view. It has been possible to make some twenty radionuclides obvious in the produced effluents and to determine the volume activity of these effluents for each radionuclide. The whole of results show that in a general way, the irradiation levels are low during the usual reactor functioning. [French] Les auteurs fournissent les resultats des mesures de radioprotection oui ont ete effectuees aupres de la pile Osiris pendant la montee en puissance et au cours des premiers fonctionnements a 50 megawatts. Les mesures portent sur les debits de dose absorbee dans les locaux, l'activation de l'eau et la contamination atmospherique. L'influence de la couche chaude des mouvements d'eau et du debit d'eau dans la cheminee du coeur sur le debit de dose absorbee au niveau de la passerelle surplombant le coeur de la pile, a ete etudiee. Les modifications aux dispositifs de protection, qui ont ete proposees a la suite des mesures, et l'effet de ces modifications sur les resultats des mesures sont indiques ensuite. Le processus de regeneration d'une chaine d'epuration de l'eau a ete examine sous l'angle de la radioprotection. Il a ete possible de mettre en evidence une vingtaine

  12. OSIRIS reactor radioprotection, radioprotection measurements performed during the power rise and the first 50 megawatt operation; Radioprotection de la pile OSIRIS, mesures de radioprotection effectuees au cours de la montee en puissance et des premiers fonctionnements a 50 megawatts

    Energy Technology Data Exchange (ETDEWEB)

    Fanton, B; Lebouleux, P

    1967-12-01

    The authors supply the results of the measurements that have been made near the Osiris reactor during the power increase and during the first functioning at 50 megawatts. The measurements relate to the absorbed dose rates in the premises, the water activation and the atmospheric contamination. The influence of the heat layer of water movements and the water rate in the core chimney on the absorbed dose rate at the footbridge level overhanging the pile core has been studied. The modifications to the protection devices that have been proposed after the measurements and the effect of these modifications on the results of the measures are given then. The regeneration process of a water purification chain has been examined from the radiation protection point of view. It has been possible to make some twenty radionuclides obvious in the produced effluents and to determine the volume activity of these effluents for each radionuclide. The whole of results show that in a general way, the irradiation levels are low during the usual reactor functioning. [French] Les auteurs fournissent les resultats des mesures de radioprotection oui ont ete effectuees aupres de la pile Osiris pendant la montee en puissance et au cours des premiers fonctionnements a 50 megawatts. Les mesures portent sur les debits de dose absorbee dans les locaux, l'activation de l'eau et la contamination atmospherique. L'influence de la couche chaude des mouvements d'eau et du debit d'eau dans la cheminee du coeur sur le debit de dose absorbee au niveau de la passerelle surplombant le coeur de la pile, a ete etudiee. Les modifications aux dispositifs de protection, qui ont ete proposees a la suite des mesures, et l'effet de ces modifications sur les resultats des mesures sont indiques ensuite. Le processus de regeneration d'une chaine d'epuration de l'eau a ete examine sous l'angle de la radioprotection. Il a ete possible de mettre en evidence une vingtaine de radionucleides dans les effluents produits et de

  13. Instrument for continuous supervision of the radioactivity of CO{sub 2} coolant in piles - DCCA -CO{sub 2} (1960); Dispositif de controle continu de la radioactivite du CO{sub 2} de refroidissement des piles - DCCA - CO{sub 2} (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Fitoussi, L [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This paper describes an apparatus for continuous measurement of CO{sub 2} activity, which can be used on piles cooled by circulation of gas. The first part is devoted mainly to describing the apparatus used and the character of the radioactivity and thermodynamic measurements carried out, and giving the general characteristics of the gas circuit required if the instrument is to be suitably gas-tight. In the second part theoretical calculations are given, particularly on the determination of the ionisation current in an ionisation chamber with circulating gas. Several parameters enter into this determination, such as the mean path of {beta} particles in the ionisation chamber, the linear number of ion pairs formed in the gas by these {beta} particles as a function of their energy, the temperature and pressure of the gas in the ionisation chamber. This part also evaluates the sensitivity areas of the apparatus for measuring the concentrations of radioactive gases such as argon-41 and fission gases from uranium-235 in the CO{sub 2} coolant. In the last part are described the results of measurements performed with such an apparatus on the pile EL2, the special investigations carried out on the CO{sub 2} coolant of this pile, and the information gained during normal operation and during accidents. The DCCA - CO{sub 2} which has just been put in operation at G2 is briefly presented. In the conclusion the possibilities offered by this apparatus are underlined. (author) [French] Ce rapport a pour but de presenter le Dispositif de Controle continu de l'Activite du CO{sub 2} pouvant etre utilise aupres des piles refroidies par une circulation de gaz. La premiere partie du rapport consiste essentiellement a decrire l'ensemble de l'appareillage mis en oeuvre, a preciser la nature des mesures de radioactivite et de thermodynamique effectuees et a citer les caracteristiques generales du circuit de gaz pour avoir un dispositif presentant une etancheite efficace. Dans la seconde

  14. Instrument for continuous supervision of the radioactivity of CO{sub 2} coolant in piles - DCCA -CO{sub 2} (1960); Dispositif de controle continu de la radioactivite du CO{sub 2} de refroidissement des piles - DCCA - CO{sub 2} (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Fitoussi, L. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This paper describes an apparatus for continuous measurement of CO{sub 2} activity, which can be used on piles cooled by circulation of gas. The first part is devoted mainly to describing the apparatus used and the character of the radioactivity and thermodynamic measurements carried out, and giving the general characteristics of the gas circuit required if the instrument is to be suitably gas-tight. In the second part theoretical calculations are given, particularly on the determination of the ionisation current in an ionisation chamber with circulating gas. Several parameters enter into this determination, such as the mean path of {beta} particles in the ionisation chamber, the linear number of ion pairs formed in the gas by these {beta} particles as a function of their energy, the temperature and pressure of the gas in the ionisation chamber. This part also evaluates the sensitivity areas of the apparatus for measuring the concentrations of radioactive gases such as argon-41 and fission gases from uranium-235 in the CO{sub 2} coolant. In the last part are described the results of measurements performed with such an apparatus on the pile EL2, the special investigations carried out on the CO{sub 2} coolant of this pile, and the information gained during normal operation and during accidents. The DCCA - CO{sub 2} which has just been put in operation at G2 is briefly presented. In the conclusion the possibilities offered by this apparatus are underlined. (author) [French] Ce rapport a pour but de presenter le Dispositif de Controle continu de l'Activite du CO{sub 2} pouvant etre utilise aupres des piles refroidies par une circulation de gaz. La premiere partie du rapport consiste essentiellement a decrire l'ensemble de l'appareillage mis en oeuvre, a preciser la nature des mesures de radioactivite et de thermodynamique effectuees et a citer les caracteristiques generales du circuit de gaz pour avoir un dispositif presentant une etancheite efficace

  15. The diode pump: its application to nuclear particle counting and to the detection of rapid neutronic power excursions in atomic piles (1962); La pompe a diodes, son application au comptage de particules nucleaires et a la detection des excursions rapides de puissance neutronique d'une pile atomique (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Nicolo, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-05-15

    This work deals in particular with three applications of an electronic device whose principle is based on that of the diode pump. 1- Linear response circuit 2- Logarithmic response circuit 3- Detection of neutronic power excursions in atomic piles using a circuit or a combination of several circuits of the linear response type. Each of the applications has been studied theoretically and experimentally. Finally, the detection of rapid power excursions is extensively discussed with reference to the many methods available, emphasis being laid on the rapidity of the electronic response. (author) [French] Cet ouvrage traite plus particulierement de trois applications d'un dispositif electronique dont le principe de fonctionnement est base sur celui de la pompe a diodes. 1- Circuit a reponse lineaire 2- Circuit a reponse logarithmique 3- Detection des excursions de puissance neutronique d'une pile atomique a l'aide d'un circuit ou d'une association de plusieurs circuits a reponse lineaire. Chacune des applications fait l'objet d'une etude theorique et experimentale. Enfin, la detection des excursions rapides de puissance est tres largement discutee a travers plusieurs methodes, notamment sur la partie concernant la rapidite de reponse de l'electronique. (auteur)

  16. Study of a device for the direct measurement of the fission gas pressure inside an in-pile fuel element; Etude d'un dispositif pour la mesure directe de la pression des gaz de fission a l'interieur d'un element combustible en pile

    Energy Technology Data Exchange (ETDEWEB)

    Lavaud, B; Uschanoff, S [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The fission gas pressure inside a fuel element made of a refractory fuel constitutes an important limiting factor for the burn-up. Although it is possible to calculate approximately the volume of gas produced outside the fuel during its life-time; it is nevertheless very difficult to evaluate the pressure since the volume allowed to the fission gases, as well as their temperature are known only very approximately. This physical value, which is essential for the technologist, can only be known by direct in-pile measurement of the pressure. The report describes the equipment which has been developed for this test. (authors) [French] La pression des gaz de fission a l'interieur d'un element combustible a combustible refractaire constitue une des limitations importantes du taux de combustion. Si on peut approcher par calcul la determination du volume, des gaz degages hors du combustible au cours de sa vie, il est par contre tres difficile d'evaluer la pression car le volume alloue aux gaz de fission et leur temperature sont tres mal connus. Cette donnee essentielle pour le technologue ne peut etre atteinte que par une mesure directe en pile de la pression. Le rapport decrit l'appareillage qui a ete mis au point pour cet essai. (auteurs)

  17. La culture comme dynamique créatrice en région

    OpenAIRE

    Marquaille, Benoît

    2013-01-01

    L’exposé met en valeur le rôle de la culture dans la valorisation des dynamiques socio-culturelles, et donne quelques exemples réussis de coopération dans ce domaine entre la France et le Liban. The paper emphasizes the role of culture in valorizing social and civic dynamics, by giving some examples of manifestations organized in the Région Ile-de-France, such as in cooperation between France and Lebanon.

  18. L'agglomeration oranaise jeux d'acteurs et dynamique urbaine ...

    African Journals Online (AJOL)

    L'agglomération oranaise connaît actuellement une croissance urbaine importante entraînant des évolutions économiques et socioculturelles considérables. Partant de là, une question nous interpelle: Quels sont les mécanismes à la base de la dynamique d'urbanisation, les processus de restructuration et de ...

  19. determination des parametres influents de la dynamique des forets

    African Journals Online (AJOL)

    Administrateur

    Chev. Leguminoseae-Mim. LOL. Loloti. Lannea welwitschii (Hiern) Engl. Anacardiaceae. LON. Lohonfé. Celtis adolphi-frederici Engl. Ulmaceae. LOT. Lotofa. Sterculia rhinopetala K.Schum. Sterculiaceae. MEL. Mélégba. Berlinia confusa Hoyle.

  20. Dynamique des populations du foreur des tiges du cacaoyer ...

    African Journals Online (AJOL)

    Objectif : Le foreur de tiges du cacaoyer, Eulophonotus myrmeleon Felder cause aujourd'hui d'énormes dégâts dans les cacaoyères ivoiriennes. La présente étude vise à déterminer les périodes de fortes attaques de ce déprédateur dans la région du Haut-Sassandra, la deuxième plus grande région de production de ...

  1. Sizing Stack and Battery of a Fuel Cell Hybrid Distribution Truck Dimensionnement pile et batterie d’un camion hybride à pile à combustible de distribution

    Directory of Open Access Journals (Sweden)

    Tazelaar E.

    2012-08-01

    à combustible et construit à des fins de démonstration, sert de base à l’étude de l’effet de la taille de la pile (kW et de la batterie (kW, kWh sur la consommation d’hydrogène du véhicule. Trois cycles de vitesse définissent les conditions spécifiques de conduite du véhicule : le NEDC pour les véhicules de faible puissance, le CSC et le cycle JE05. L’ECMS (Equivalent Consumption Minimization Strategy est utilisée pour déterminer les consignes pour la pile à combustible et la batterie. Cette stratégie de commande permet d’atteindre une consommation proche du minimum global, obtenu par la programmation dynamique (DP. Le problème de dimensionnement peut être résolu en utilisant la programmation dynamique et l’ECMS a l’avantage, par rapport à la programmation dynamique, de pouvoir être mise en oeuvre en temps réel. Pour le véhicule et matériels considérés, les trois cycles de conduite permettent d’obtenir les puissances nominales optimales pour la pile à combustible à savoir environ trois fois la puissance moyenne demandée par le conducteur. Cela montre que le dimensionnement de la pile à combustible pour la puissance moyenne ou maximale, n’est pas nécessairement optimale vis-à-vis de la sobriété en carburant. La batterie est dimensionnée pour fournir la différence entre la puissance nominale de la pile à combustible et le pic de puissance dans la demande totale en puissance électrique. Le dimensionnement de la batterie est dominée par ses capacités de tenue en puissance. Par conséquent, un taux plus haut entre kW et kWh cause une diminution du poids de la batterie qui à son tour conduit à une consommation d’hydrogène plus basse. La capacité de stockage d’énergie de la batterie ne devient un problème que pour les taux de C-ratio supérieurs à 30. Par rapport à un prolongateur d’autonomie (RE où la taille de la pile est comparable à la puissance moyenne et où la pile est exploitée sur un niveau

  2. Les prairies de l’estuaire de la Loire : étude de la dynamique de la végétation de 1982 à 2014

    Directory of Open Access Journals (Sweden)

    Mathieu Le Dez

    2017-01-01

    Full Text Available L’analyse diachronique de cartes de végétation est réalisée pour caractériser les dynamiques de la végétation de l’estuaire de la Loire à différentes échelles spatiales et temporelles. Le modèle des matrices de transition est utilisé pour décrire quantitativement les dynamiques observées. Les analyses révèlent notamment la régression des prairies, le développement des roselières et des boisements ainsi que la progression des végétations halophiles. Ces résultats sont mis en relation avec l’évolution des usages sur ce territoire et les modifications du fonctionnement hydro-sédimentaire de l’estuaire.

  3. New results concerning the behaviour of fission gases in in-pile UO{sub 2} at high temperatures; Resultats nouveaux sur le comportement des gaz de fission a haute temperature dans l'UO{sub 2} en pile

    Energy Technology Data Exchange (ETDEWEB)

    Soulhier, R; Schurenkamper, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The authors consider in the first part the various phenomena giving rise to the production of fission gases towards the exterior of nuclear fuels. The following aspects are dealt with: diffusion, for which is considered the influence of the predecessors of the radioactive gases, the fission recoil, atom expulsion along the fission paths and the evaporation. In the second part the authors present the results obtained on UO{sub 2} samples subjected to irradiation at temperatures of between 150 and 2000 deg C: - At low temperatures the variation of the amount produced as a function of the half-life of the isotopes studied shows that recoil is hot the only cause of gas production. - Above 1800 deg C, a weight loss by evaporation has been observed and the influence of this phenomenon on gas liberation has been studied; thus the fraction of {sup 135}Xe liberated at 2000 deg C by processes other than evaporation is of the order of 10 per cent. - The influence of the various mechanism on the overall effect as a function of temperature is discussed. (authors) [French] Dans une premiere partie, les auteurs etudient les differents phenomenes pouvant donner lieu au degagement des gaz de fission hors d'un combustible. Sont traites successivement: la diffusion, pour laquelle on discute l'influence des predecesseurs des gaz radioactifs, le recul de fission, l'expulsion des atomes le long des trajets de fission et l'evaporation. Dans une deuxieme partie ils exposent les resultats obtenus sur des echantillons d'UO{sub 2} portes sous irradiation a des temperatures comprises entre 150 deg C et 2000 deg C: - A basse temperature la variation de la quantite degagee suivant la periode des isotopes etudies montre que le recul n'est pas la seule cause du degagement des gaz. - Au-dessus de 1800 deg C on a note une perte de poids par evaporation et on a evalue l'influence de ce phenomene sur la liberation des gaz: ainsi la fraction du {sup 135}Xe liberee a 2000 deg C par d'autres processus

  4. Dynamique chromatinienne dans la réparation de l'ADN : analyse fonctionnelle du complexe histone acétyltransférase NuA4 dans la réparation des dommages à l'ADN

    OpenAIRE

    Jobin-Robitaille, Olivier

    2005-01-01

    Tableau d'honneur de la Faculté des études supérieurs et postdoctorales, 2005-2006 La cellule dispose de plusieurs mécanismes de réparation, nécessitant tous l'accès à l'ADN, afin de prévenir les perturbations occasionnées par l'instabilité génomique. La structure des chromosomes eucaryotes (chromatine) forme une barrière physique empêchant l'accessibilité à l'ADN et ainsi les processus biologiques nucléaires tels la transcription, réplication, recombinaison et réparation des dommages de ...

  5. La dynamique des régimes de régulation de la sûreté nucléaire française à la lumière de ses instruments

    OpenAIRE

    Chanton , Olivier; Mangeon , Michael; Pallez , Frédérique; Rolina , Grégory

    2016-01-01

    International audience; L’accident de Fukushima a provoqué une prise de conscience sans précédent concernant l’importance des risques naturels à l’échelle internationale. En mettant en cause plusieurs aspects institutionnels, et notamment les liens de dépendance entre l’autorité de sûreté nucléaire et le ministère de l’industrie japonais, les analyses de l’accident posent également la question de la gouvernance et de la régulation des risques nucléaires avec une acuité nouvelle (Delamotte 201...

  6. Contribution méthodologique à l'analyse cinématique et dynamique tridimensionnelle du mouvement

    OpenAIRE

    DUMAS, R

    2010-01-01

    L'ensemble des travaux présentés dans ce mémoire d'HDR porte sur l'analyse tridimensionnelle du mouvement et plus particulièrement sur les aspects méthodologiques des calculs de cinématique et de dynamique.Plusieurs pistes d'amélioration qui ont été explorées pour lever des verrous scientifiques en analyse cinématique sont présentées : généralisation des « systèmes de coordonnées segmentaires », adaptation des « systèmes de coordonnées articulaires », compensation des « artefacts des tissus m...

  7. Measure of the efficiency of a long counter of Hanson's type and use of this counter for the survey of the slow neutrons coming from the reactor of Chatillon; Mesure de l'efficacite d'un long compteur du type Hanson et utilisation de ce compteur a l'etude des neutrons lents sortant de la pile de Chatillon

    Energy Technology Data Exchange (ETDEWEB)

    Barloutaud, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1953-07-01

    A detection device of fast neutrons of efficiency almost independent of the energy of the neutrons has been achieved. It efficiency has been measured in absolute value for groups of neutrons of different energies. This device allowed to get some indications on the energy composition of the neutrons leaving from the reactor of Chatillon. (author) [French] Un dispositif de detection de neutrons rapides d'efficacite pratiquement independante de l'energie des neutrons a ete realise. Son efficacite a ete mesuree en valeur absolue pour des groupes de neutrons de diverses energies. Ce dispositif a permis obtenir quelques indications sur la composition energetique des neutrons sortant de la pile de Chatillon. (auteur)

  8. (Vitaceae) dans le Parc National des Iles de la M

    African Journals Online (AJOL)

    SARAH

    31 juil. 2015 ... 3Ecole Régionale Post-Universitaire d'Aménagement et de gestion Intégrés des Forêts et ... Méthodologie et résultats : Des essais de contrôle biologique et physique ont été testés. ..... Dynamique des populations de l'arbre.

  9. Annales des Sciences Agronomiques - Vol 16, No 2 (2012)

    African Journals Online (AJOL)

    Effet de la monoculture des poacees sur le controle de Hyptis suaveolens ... Dynamique des champignons endomycorhiziens dans les jachères manioc sur ... de gestion de la fertilité des sols dans la commune de ouaké au Nord-Ouest du ...

  10. Dynamiques de résistance aux normes révolutionnaires à Cuba

    OpenAIRE

    Geoffray, Marie-Laure

    2013-01-01

    Les normes du régime révolutionnaire sont, à Cuba, inscrites dans l’espace. Elles fonctionnent comme des signes performatifs qui à la fois rappellent constamment la présence du pouvoir et catégorisent les individus selon leur conformité aux normes. Mais, depuis la crise économique des années 1990, des logiques centrifuges à l’œuvre au sein de la société cubaine viennent remettre en question la capacité du régime à générer une socialisation révolutionnaire homogène. On observe des dynamiques s...

  11. In-situ test of the static behaviour of a pile foundation subjected to thermo-mechanical solicitations. Intermediate report of January 1999; Test en conditions reelles du comportement statique d`un pieu soumis a des sollicitations thermo-mecaniques. Rapport intermediaire de janvier 1999

    Energy Technology Data Exchange (ETDEWEB)

    Moreni, M.; Laloui, L.; Steinmann, G. [and others

    1999-10-01

    A pile foundation of the polyvalent building in the north quarter of the Federal Institute of Technology in Lausanne (EPFL) was equipped with a hydraulic circuit in order to be able to inject heat into the pile (i.e. the pile was transformed into a heat exchanger pile). Load, deformation and temperature sensors were installed in the pile in order to assess the influence of thermal solicitations on the static behaviour of the pile. In the initial phase of the project (up to May 1998), the design and realisation of the heat exchanger pile was scheduled together with the installation of the measurement sensors. The next phase, ending one month after publication of the present report, is comprised of series of thermal solicitations applied in the pile, called tests. Due to the construction of the building, the weight on the pile increases between each test. This report contains the presentation of all the measurements done in the 6 tests performed in between the completion of each floor of the building. The pile was heated with a temperature difference of 15 K for each test, except for the first one, where it reached 22 K (this was before the construction of the building`s basement). The temperatures and deformations induced by the thermal and mechanical solicitations were measured and the stresses calculated at different depths of the pile (fluid temperatures, flow rate, electric and thermal powers) were continuously recorded. Sonic coring and a control using the reflection method were performed to determine the pile elastic modulus and the quality of its concrete. The last phase of the project (March - December 1999) deals with the analysis of the measurements in order to assess the influence of a temperature variation on the ability of the pile to support the load of the building [Francais] Un pieu du batiment polyvalent du Quartier Nord de l`Ecole Polytechnique Federale de Lausanne (EPFL) a ete equipe d`un circuit hydraulique pour pouvoir lui injecter de la chaleur

  12. Kinetics of heterogeneous systems; La cinetique des milieux heterogenes

    Energy Technology Data Exchange (ETDEWEB)

    Deniz, V [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    parametres en milieu fini sont exprimes en fonction des parametres correspondants en milieu infini par l'intermediaire du laplacien et des aires de migration anisotropes, et d'autre part que tous ces parametres sont exprimes en fonction des integrales sur une seule cellule et non sur toute la pile. Une etude preliminaire moins detaillee est d'abord faite pour bien distinguer entre ce qu'on appelle 'parametres dynamiques' et 'parametres statiques' et pour preciser le sens que l'on donne aux deux termes dans ce rapport. On donne en annexe des traitements approximatifs a un groupe pour l'etude de la structure fine dynamique, de la constante de temps en milieu infini, et des coefficients de diffusion anisotrope dans des reseaux non-multiplicateurs. (auteur)

  13. La périurbanisation résidentielle en Belgique à la lumière des contextes suisse et danois: enracinement, dynamiques centrifuges et régulations collectives

    OpenAIRE

    Halleux, Jean-Marie; Bruck, L.; Mairy, N.

    2002-01-01

    Par rapport à ses voisins européens, la Belgique apparaît marquée par une périurbanisation à la fois plus importante et plus éclatée, ce dont résultent sans conteste de nombreux accrochages par rapport aux principes stratégiques du développement durable. Le présent article se propose d’étudier les causes de l’éclatement urbain qui affecte le territoire belge à la lumière d’une comparaison avec la Suisse et le Danemark, deux pays réputés pour avoir mis sur pied des politiques relativement effi...

  14. The direct conversion of heat into electricity in reactors; Conversion directe de la chaleur en electricite dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Devin, B; Bliaux, J; Lesueur, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    pile atomique a ete etudiee dans la triple perspective de son utilisation soit comme source d'energie de servitude dans un engin spatial, soit en tete d'un systeme conventionnel de conversion dans les installations de puissance, soit enfin associee a la conversion thermoelectrique dans des installations de tres faible puissance. Les etudes en laboratoire ont porte principalement sur les travaux d'extraction electronique des metaux et composes et leur evolution a haute temperature. Des convertisseurs fournissant jusqu'a 50 amperes sous 0,4 volt avec un rendement voisin de 10 p. 100 ont ete realises en laboratoire; les emetteurs chauffes par bombardement electronique etaient constitues de tungstene recouvert d'un depot de carbure d'uranium ou de molybdene recouvert de cesium. Les principaux aspects du couplage entre le convertisseur et la pile atomique ont ete examines du point de vue electronique: influence de la desadaptation de la charge sur la temperature de l'emetteur et influence du flux thermique unitaire sur la temperature de l'emetteur et la stabilite du convertisseur. Des convertisseurs utilisant le carbure d'uranium comme emetteur electronique ont ete experimentes en pile. Des essais ont ete effectues en regime transitoire en vue de determiner les parametres dynamiques. Les reseaux d'adaptation a la charge ont pu etre construits et on en a deduit les performances globales de plusieurs cellules couplees de maniere a former un barreau de reacteur. Ces donnees sont indispensables pour la conception d'un systeme de controle d'une pile a conversion thermoionique, On a examine theoriquement les problemes de fiabilite des convertisseurs thermoioniques associes en serie dans un meme barreau de combustible. Enfin, on a trace les isothermes d'absorption a la temperature ambiante du krypton et du xenon sur un charbon active en vue d'etudier le degagement des produits de fission dans un convertisseur. (auteurs)

  15. Development of the control assembly pattern and dynamic analysis of the generation IV large gas-cooled fast reactor (GFR); Developpement du design d'un assemblage de controle et analyse dynamique des reacteurs a neutrons rapides de quatrieme generation refroidis au gaz

    Energy Technology Data Exchange (ETDEWEB)

    Girardin, G.

    2009-07-09

    was paid to have each individual fuel sub-assembly and CA represented, in order to allow the analysis of local deformations of the 3D distributions of power and safety related parameters, such as the coolant, cladding and fuel temperatures. The validation of the coupled full core models was performed against reference ERANOS-VARIANT calculations. (author) [French] Le travail de recherche a ete mene dans le contexte du RNR-G de reference a 2400 MWth. Le but principal a ete de developper et de qualifier le design de l'assemblage de controle et le schema d'implantation correspondant a ce systeme. Le travail a ete realise en trois phases successives et complementaires: (1) la validation des outils neutroniques, (2) le developpement du design de l'assemblage de controle et les etudes statiques correspondantes, (3) les etudes du comportement dynamique du coeur durant des transitoires hypothetiques lies aux assemblages de controle. Pendant la premiere phase de la these, le reseau test de reference de PROTEUS utilise dans ces experiences, a ete reinterprete avec ERANOS et la bibliotheque nucleaire ajustee ERALIB1. De maniere complementaire, des calculs de references ont ete realises avec le code de Monte Carlo MCNPX, visant a verifier les resultats deterministes, et a analyser la sensibilite des resultats aux differentes modernes librairies. Pour les taux de reactions principaux, la nouvelle analyse du reseau de reference GCFR-PROTEUS donne generalement des resultats en bon accord - dans l'incertitude experimentale 1{sigma} - avec les resultats experimentaux, ainsi qu'avec les simulations de Monte Carlo. L'utilisation d'ERANOS-2.0/ERALIB1 comme outil neutronique de reference a ainsi pu etre demontree pour l'analyse du RNR-G. Dans une seconde phase de cette recherche, le design de l'assemblage de controle (AC) du GFR a ete developpe, base sur des calculs a caractere iteratif, neutroniques et thermo-hydrauliques. En premier, des

  16. Marked bengal pink. A dynamic test using marking doses; its value in jaundice diagnosis; Rose bengale marque. Epreuve dynamique a doses tracantes; sa valeur dans le diagnostic des icteres

    Energy Technology Data Exchange (ETDEWEB)

    Kellershohn, C; Desgrez, A [Commissariat a l' Energie Atomique, Service Frederic Joliot, Service de Biologie, Saclay (France).Centre d' Etudes Nucleaires; Caroli, J [Hopital Saint Antoine, 75 - Paris (France); Delaloye, B [Lausanne (Switzerland)

    1961-07-01

    The authors do a historic calling back of the differential study of jaundices thanks to the semi logarithmic gradients of expurgation of bromine sulphone-phthalein and thanks to the time of appearance of this material in the bile collected by duodenal tubing. They sum up likewise the foreign works which lead to take the place of this test, the outside count at the level of the head, the liver, and the abdomen after intravenous injection of a running dose of marked Rose Bengal. They specify the technical conditions of this test and report an experience which corroborate its value, its accuracy and the interest of its using in the different types of jaundices (hepatitis and obstructive types). (author) [French] Les auteurs font un rappel historique de l'etude differentielle des icteres grace aux pentes semi-logarithmiques d'epuration de la bromesulfonephtaleine et grace au temps d'apparition de cette substance dans la bile recueillie par tubage duodenal. Ils resument egalement les travaux etrangers qui tendent a substituer a cette epreuve le comptage externe au niveau de la tete, du foie et de l'abdomen, apres injection intraveineuse d'une dose tracante de rose bengale marque. Ils precisent les conditions techniques de cette epreuve et rapportent une experience qui confirme sa valeur, son exactitude et l'interet de son utilisation dans les differentes categories d'icteres par hepatite et par obstruction. (auteur)

  17. Marked bengal pink. A dynamic test using marking doses; its value in jaundice diagnosis; Rose bengale marque. Epreuve dynamique a doses tracantes; sa valeur dans le diagnostic des icteres

    Energy Technology Data Exchange (ETDEWEB)

    Kellershohn, C.; Desgrez, A. [Commissariat a l' Energie Atomique, Service Frederic Joliot, Service de Biologie, Saclay (France).Centre d' Etudes Nucleaires; Caroli, J. [Hopital Saint Antoine, 75 - Paris (France); Delaloye, B. [Lausanne (Switzerland)

    1961-07-01

    The authors do a historic calling back of the differential study of jaundices thanks to the semi logarithmic gradients of expurgation of bromine sulphone-phthalein and thanks to the time of appearance of this material in the bile collected by duodenal tubing. They sum up likewise the foreign works which lead to take the place of this test, the outside count at the level of the head, the liver, and the abdomen after intravenous injection of a running dose of marked Rose Bengal. They specify the technical conditions of this test and report an experience which corroborate its value, its accuracy and the interest of its using in the different types of jaundices (hepatitis and obstructive types). (author) [French] Les auteurs font un rappel historique de l'etude differentielle des icteres grace aux pentes semi-logarithmiques d'epuration de la bromesulfonephtaleine et grace au temps d'apparition de cette substance dans la bile recueillie par tubage duodenal. Ils resument egalement les travaux etrangers qui tendent a substituer a cette epreuve le comptage externe au niveau de la tete, du foie et de l'abdomen, apres injection intraveineuse d'une dose tracante de rose bengale marque. Ils precisent les conditions techniques de cette epreuve et rapportent une experience qui confirme sa valeur, son exactitude et l'interet de son utilisation dans les differentes categories d'icteres par hepatite et par obstruction. (auteur)

  18. Non Linear Dynamics and Chaos (La Dynamique Non-Lineaie et le Chaos)

    Science.gov (United States)

    1993-06-01

    du cerveau humain, tout autant que les "machines neuronales" en cours de pour plus de details voir en ref. [ I Il’article de A. Favre d~veloppement...l’hypothese sur la faqon syst~rnes nerveux. L’id~e selon laquelle la dont varient les coefficients avec le temps dynamique du cerveau , dans certains...coefficients de interprke comme la preuve d’un caract~re H’quation temporelle sont constants. 11 n’est fugitif des attracteurs du cerveau ? Ou bien

  19. Trace element and isotopic compositions of Vietnamese basalts: implications for mantle dynamics in the southeast Asian region; Compositions isotopiques et en elements en trace des basaltes vietnamiens: implications pour la dynamique du manteau en Asie du Sud-Est

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, H.; Fower, M. [Illinois Univ., Chicago, IL (United States); Nguyen, H. [Tokyo Univ. (Japan); Nguyen, X.B.; Nguyen, T.Y. [Institute of Nuclear Science and Technology, Hanoi (Viet Nam)

    1996-12-31

    Cenozoic basalts in Indo-China are part of a regional melting episode along the rifted Eurasian margin. Trace element and isotopic compositions of Vietnamese basalts are used to place constraints on the extent of lithospheric and asthenosphere contributions to the melts and possible mantle dynamic implications. The {sup 87}Sr/{sup 86}Sr, {sup 207}Pb/{sup 204}Pb, and {sup 208}Pb/{sup 204}Pb isotopic ratios of the basalts reflect minimal crustal wall rock reaction, and variable enrichment in EM1 and EM2 of a {sup 208}Pb-rich MORB-like source. Some, but not all, of this variation corresponds to the age of lithospheric sector penetrated. Basalts erupted through a cratonic, central sector (e.g. at Quang Ngai, Pleiku, Song Cau, Kong Plong, and Buon Ma Thuot) and off-cratonic, southwest sector (e.g. Phuoc Long) resemble those of EM2-rich basalts from southern and southeaster China and the South China Sea. Basalts from an off-cratonic, southeast sector (e.g. from Dalat, Xuan Loc, and the offshore Ile des Cendres-Phu Cuy complex) reflect mixing between a low- {sup 206}Pb/{sup 204}Pb, high-{sup 208}Pb/{sup 204}Pb, EM1-like component, and resemble basalts from northwest Taiwan, eastern and northeastern China, and parts of the Japan Sea. While EM2 tends to characterise lithospheric sectors, presence of EM1 in off-cratonic rather than cratonic basalts implies an asthenosphere rather than lithospheric source. Pervasive presence of EM1 in southeast Asian and marginal basin asthenosphere corresponds with thermally-anomalous mantle and may involve delaminated cratonic substrate entrained by mobile, extruded asthenosphere. (authors) 85 refs.

  20. The controlled of the materials by the method of oscillation at the reactor core of Chatillon; Le controle des materiaux par la methode d'oscillation a la pile de Chatillon

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Nuclear controls has for aim to determine the validity of materials intended to be used for the construction of the reactor core. The cross-section of capture of these materials has to be measured while comparing them either to a standard of the same material, either to an element of cross-section supposed known. We studied the disruption of the working of the reactor generated by the periodic introduction of a sample of the studied material. This method is based on the measure of the phase angle of the signal provided by the ionization chamber. This signal results from the composition of a local signal and an aggregate signal due to the effects of diffusion and capture. This method permits the comparison of the capture of 2 samples very dispersive and few capturing as the graphite, the beryllium, the beryllium oxide, with a good precision. It permits to determine the cross-section of capture of elements as magnesium or aluminum. (M.B.) [French] Le controle nucleaire a pour but de determiner la valeur des materiaux destines a etre utilises pour la construction des piles. II s'agit de mesurer la section efficace de capture de ces materiaux en les comparant soit a un echantillon etalon du meme materiau, soit a un element de section efficace supposee connue. On etudie la perturbation du fonctionnement de la pile engendree par l'introduction periodique d'un echantillon du materiau a etudier. Cette methode est basee sur la mesure de l'angle de phase du signal fourni par la chambre d'ionisation. Ce signal resulte de la composition d'un signal local et d'un signal global dus aux effets de diffusion et de capture. Cette methode permet la comparaison de la capture de 2 echantillons de corps tres diffusants et peu capturants comme le graphite,le beryllium, l'oxyde de beryllium, avec une bonne precision. Elle permet par ailleurs de determiner la section efficace de capture de corps tels que le magnesium ou l'aluminium. (M.B.)

  1. The reactor Cabri; La pile cabri

    Energy Technology Data Exchange (ETDEWEB)

    Ailloud, J; Millot, J P [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1964-07-01

    circumstances... - experimental investigations on power excursions linked with precise initial conditions: the aim of this work is to define the basis for theoretical research, and the limits beyond which the risks of explosion cease to be negligible. The research work will be done so as to enable checking with outside reactor experiments and to continue them in the explosion field. - studies of the behaviour of the reactor control-instrumentation. - experimental investigations related with transient operation with initial short life (study of boiling, temperature measurements, vacuum pressure and fraction...) with the aim of defining the hypotheses of a theory on swimming-pool reactor kinetics related to heat transfer phenomena, - investigations of the behaviour of fuels in reactors (these experiments are planned to be carried out in loops) Preliminary experimental results. CABRI went critical on the 21 December 1963. The first transient experiments are expected for March 1964. (authors) [French] II devenait necessaire de construire en France une pile qui permette d'etudier les conditions de fonctionnement des installations futures, de choisir, tester et mettre au point les dispositifs de securite a adopter. On a choisi une pile a eau, type de pile qui correspond aux constructions les plus nouvelles du CEA en matiere de piles laboratoire ou d'universite; il importe en effet de pouvoir evaluer les risques presentes et d'etudier les possibilites d'augmentation de puissance constamment demandees par les utilisateurs: il est particulierement interessant d'eclaircir les phenomenes d'oscillation de puissance et les risques de calefaction (burn out). Les programmes de travaux sur CABRI seront harmonises avec les travaux effectues sur les Spert americains de meme type; lors de sa construction des contacts fructueux ont ete etablis avec les specialistes americains qui ont defini les premiers de ces reacteurs. La communication donne une description sommaire de la pile et decrit le

  2. Taming Windscale's piles

    International Nuclear Information System (INIS)

    Adams, A.L.

    1989-01-01

    The options as to what to do with the Windscale Piles are being assessed before a final decision on decommissioning is made. Both Piles were shutdown in 1957 following the fire in the Pile number 1. Pile 1 still contains 22 tons of natural uranium fuel. The details of graphite moderator content, biological shielding and other components and containment are given. The fuel and isotope channels in Pile 2 have been examined and the air and water ducts have been inspected. The chimneys of both Piles are contaminated and all entrances have been sealed. Before any work starts the air outlet ducts will be sealed from the chimney and a ventilation system installed. A manipulator is being prepared to remove the remaining fuel elements from both Piles. The proposed decommissioning programme for both Piles is outlined. (U.K.)

  3. The pile EL3; Pile EL3

    Energy Technology Data Exchange (ETDEWEB)

    Robert, J.; Raievski, V. [Commissariat a l' Energie Atomique, Paris (France). Centre d' Etudes Nucleaires; Hainzelin, J. [Chantiers de l' Atlantique (Penhoet-Loire), 75 - Paris (France)

    1959-07-01

    The programme of the high flux laboratory pile EL3 was laid down in october 1954. It is a heavy-water moderated and cooled pile. The fuel rods are of uranium metal with 1.6 per cent - 2 per cent of molybdenum, with aluminium canning. The maximum thermal flux in the moderator is 10{sup 14} n/cm{sup 2}/s. Studies began in january 1955, construction in may 1955, and the first divergence took place in July 1957. This report gives a general description of the pile and its adjacent buildings, the physical study of the pile, and certain technological studies carried out for the construction of EL3. (author) [French] Le programme de la pile laboratoire a haut flux EL3, a ete fixe en octobre 1954. C'est une pile moderee et refroidie a l'eau lourde. Les barres de combustible sont en uranium metal a 1,6 pour cent - 2 pour cent de molybdene, gainees a l'aluminium. Le flux thermique maximum dans le moderateur est de 10{sup 14} n/cm{sup 2}/s. Les etudes ont commence en janvier 1955, la construction en mai 1955, la premiere divergence a eu lieu en juillet 1957. On trouvera dans ce rapport, une description generale de la pile et de ses batiments annexes, l'etude physique de la pile et un certain nombre d'etudes technologiques executees pour la construction d'EL3. (auteur)

  4. The pile EL3; Pile EL3

    Energy Technology Data Exchange (ETDEWEB)

    Robert, J; Raievski, V [Commissariat a l' Energie Atomique, Paris (France). Centre d' Etudes Nucleaires; Hainzelin, J [Chantiers de l' Atlantique (Penhoet-Loire), 75 - Paris (France)

    1959-07-01

    The programme of the high flux laboratory pile EL3 was laid down in october 1954. It is a heavy-water moderated and cooled pile. The fuel rods are of uranium metal with 1.6 per cent - 2 per cent of molybdenum, with aluminium canning. The maximum thermal flux in the moderator is 10{sup 14} n/cm{sup 2}/s. Studies began in january 1955, construction in may 1955, and the first divergence took place in July 1957. This report gives a general description of the pile and its adjacent buildings, the physical study of the pile, and certain technological studies carried out for the construction of EL3. (author) [French] Le programme de la pile laboratoire a haut flux EL3, a ete fixe en octobre 1954. C'est une pile moderee et refroidie a l'eau lourde. Les barres de combustible sont en uranium metal a 1,6 pour cent - 2 pour cent de molybdene, gainees a l'aluminium. Le flux thermique maximum dans le moderateur est de 10{sup 14} n/cm{sup 2}/s. Les etudes ont commence en janvier 1955, la construction en mai 1955, la premiere divergence a eu lieu en juillet 1957. On trouvera dans ce rapport, une description generale de la pile et de ses batiments annexes, l'etude physique de la pile et un certain nombre d'etudes technologiques executees pour la construction d'EL3. (auteur)

  5. Introduction d'une représentation dynamique de matériau dans l'équation de diffusion du champ magnétique

    Science.gov (United States)

    Raulet, M. A.; Masson, J. P.; Gaude, D.

    1998-01-01

    The knowledge of the dynamical behavior of magnetic materials is of first importance in the iron losses prediction. For the simple shaped Epstein frame, the field diffusion equation resolution in the laminations cross section, limited to eddy currents, leads to inaccurate results. This paper presents a simple method to take into account dynamical distributed phenomena in the field diffusion equation. The study will be limited to dynamical first magnetization excitations. La connaissance du comportement dynamique des matériaux magnétiques est importante pour l'évaluation des pertes fer dans les machines électriques. Pour les sollicitations simples d'une tôle dans un cadre Epstein ou un tore fin, la résolution de l'équation de la diffusion du champ magnétique dans le plan de la section de la tôle limitée aux seuls courants de Foucault, ne fournit qu'une description insuffisamment précise des phénomènes. Cet article présente une méthode simple de prise en compte des phénomènes dynamiques locaux dans l'équation de diffusion. L'étude sera limitée à des sollicitations de première aimantation dynamique. Une validation expérimentale de ce modèle en fonction de la fréquence est aussi présentée.

  6. Chimie des interactions moléculaires

    OpenAIRE

    Lehn, Jean-Marie

    2010-01-01

    Le cours de l’année 2008-2009 a porté sur « Autoorganisation et dynamique moléculaires ». Des cours ont été donnés à l’Université de Strasbourg (3 h), à l’Université Charles de Prague (3 h) et à la City University de Hong Kong (3 h). Cours au Collège de France : Autoorganisation et dynamique moléculaires Introduction Le cours a porté sur l’évolution de la chimie supramoléculaire vers la chimie dynamique constitutionnelle (CDC) et la chimie adaptative. Du fait de la labilité des interactions n...

  7. Molecular dynamics simulations of ter-pyridine and bis-triazinyl-pyridine complexes with lanthanide cations; Etude de dynamique moleculaire de complexes de la bis-triazinyl-pyridine (BTP) et de la terpyridine avec des lanthanides(3)

    Energy Technology Data Exchange (ETDEWEB)

    Guilbaud, Ph. [CEA Valrho, (DCC/DRRV/SEMP), 30 - Marcoule (France)

    2000-07-01

    The search for ligands which specifically separate actinides(III) from lanthanides(III) by liquid-liquid extraction has prompted considerable research in the Process Design and Modeling Department ('Service d'Etude et de Modelisation des Procedes'- SEMP). Ligands with soft donor atoms AS) that are able to perform this separation have already been investigated and research is currently under way to improve their performance for high acidic feeds. Theoretical chemistry research is conducted in the Theoretical and Structural Chemistry Laboratory ('Laboratoire de Chimie Theorique et Structurale') to improve our understanding of the complexation and extraction of these cations with such ligands. Theoretical studies were first carried out for the ter-pyridine (TPY) and bis-triazinyl-pyridine (BTP) ligands that display fairly good ability to separate and extract actinide(III) from lanthanide(III) ions. Molecular dynamics simulations were performed on ter-pyridine and bis-triazinyl-pyridine complexes with three lanthanide cations (La{sup 3+}, Eu{sup 3+} and Lu{sup 3+}) for vacuum and for water solutions. These calculations were carried out without counter-ions, with three nitrate (NO{sub 3}{sup -}) ions, and, in the case of ter-pyridine, with three {alpha}-bromo-caprate anions that are likely to be used experimentally as synergistic agents for the separation and extraction of An(III) from Ln(III). Molecular dynamics simulations were first performed for vacuum to evaluate the distances between nitrogen and lanthanide atoms (Ln{sup 3+},N) and intrinsic interaction energies to poly-nitrogenous ligands with or without NO{sub 3} ions, and for both ligands. The (Ln{sup 3+},N) distances decrease and the cation/ligand interaction energies increase along the La{sup 3+}, Eu{sup 3+}, Lu{sup 3+} series, with decreasing Ln(III) ion radii. The introduction of nitrate counter-ions makes the (Ln{sup 3+},N) distances slightly higher, and the TPY/Ln{sup 3+} and BTP

  8. Detection of radioactive gases in the CO{sub 2} cooling the reactors G 2 - G 3; Detection des gaz radioactifs dans le CO{sub 2} de refroidissement des piles G2 - G3

    Energy Technology Data Exchange (ETDEWEB)

    Pouthier, J; Rossi, J [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1968-07-01

    The carbon dioxide cooling the reactors G2 - G3 contains activation gases and fission gases. It is of interest to know their concentration, for example to be able to deduce rapidly the norms which would have to be applied in the case of an incident in the circuit. Gas-phase chromatography is applied daily for carrying out analyses. The chromatogram has separate peaks due to tritium, argon 41, krypton 85 and the 133 and 135 isotopes of xenon. By integrating each peak it is possible to calculate the specific activity of each product. The construction of an apparatus for carrying out continuous measurements is under consideration. (authors) [French] Le gaz carbonique, refroidissant les reacteurs G2 - G3, contient des gaz d'activation et des gaz de fission. Il est interessant de connaitre leur teneur par exemple pour etre en mesure de deduire rapidement les normes qu'il y aurait lieu d'appliquer en cas d'incidents sur le circuit. La methode de chromatographie en phase gazeuse est employee quotidiennement pour faire des analyses. Le chromatogramme se presente sous forme de pics distincts dus au tritium, a l'argon 41, au krypton 85 et aux isotopes 133 et 135 du xenon. L'integration de chaque pic permet de calculer l'activite specifique de chaque compose. Il est envisage de construire un appareil pour des mesures en continu. (auteurs)

  9. Determination of the 20 MeV linear accelerator, new injector for the synchrotron Saturne. Choice of the electrical and dynamical particle parameters; Determination de l'accelerateur lineaire de 20 MeV, nouvel injecteur du synchrotron Saturne. Choix des parametres electriques, dynamique des particules

    Energy Technology Data Exchange (ETDEWEB)

    Prome, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-12-15

    This report takes place in the general determination of the 20 MeV linear accelerator which will be the new Saturne injector; it deals with particle dynamics. Starting from beam requirements at the output of the linac, cells lengths with variable synchronous phase angle, buncher and de-buncher parameters, beam emittances at the output in several phase spaces are successively determined. (author) [French] Dans le contexte general de la determination de l'accelerateur lineaire de 20 MeV, nouvel injecteur du synchrotron Saturne, ce rapport traite de la partie relative au mecanisme de l'acceleration des particules; a partir des caracteristiques souhaitees pour le faisceau a la sortie de cet accelerateur, on determine successivement les longueurs des cellules, compte tenu du choix d'un angle de phase synchrone variable, les caracteristiques du groupeur et du degroupeur et les emittances du faisceau en sortie dans les differents plans de phase. (auteur)

  10. Piles of objects

    KAUST Repository

    Hsu, Shu-Wei

    2010-01-01

    We present a method for directly modeling piles of objects in multi-body simulations. Piles of objects represent some of the more interesting, but also most time-consuming portion of simulation. We propose a method for reducing computation in many of these situations by explicitly modeling the piles that the objects may form into. By modeling pile behavior rather than the behavior of all individual objects, we can achieve realistic results in less time, and without directly modeling the frictional component that leads to desired pile shapes. Our method is simple to implement and can be easily integrated with existing rigid body simulations. We observe notable speedups in several rigid body examples, and generate a wider variety of piled structures than possible with strict impulse-based simulation. © 2010 ACM.

  11. Impacts des changements climatiques et de la dynamique du ...

    African Journals Online (AJOL)

    The SWAT 2003 model was used in order to realize the different simulations based on the result of the model calibration in 2009 by Dossou-Yovo. Future scenario of climate change performed by IMPETUS and future scenario of land use performed by CENATEL were also used. For the future water yield of the catchment, ...

  12. Dynamique des nouvelles technologies rizicoles en agriculture de ...

    African Journals Online (AJOL)

    ... have adopted a deliberate low purchase price policy for the local rice product, relying on importations to satisfy the rice demand at national level. Moreover, there is a lack of coordination between research, development organizations and NGOs in both the introduction and the diffusion processes of new rice varieties.

  13. Dynamique institutionnelle des transferts de gestion dans le corridor ...

    African Journals Online (AJOL)

    Ten years after their creation, the operation of the community-based natural resource management policy named 'transfert de gestion' – the 1996 GELOSE law (applied to any kind of natural resources), and the 2001 GCF decree (only applied to forests) - remains little understood. The forest corridor linking Ranomafana and ...

  14. Dynamique de structuration spatio-temporelle des populations de ...

    African Journals Online (AJOL)

    SARAH

    30 juin 2014 ... conventionnelle de la « Directive Cadre sur l'Eau de l'Union Européenne (DCE) » préconisée pour ... différence entre les indices de diversité biologique de Shannon de ... reste un outil de choix dans l'évaluation de la qualité.

  15. The pile EL3

    International Nuclear Information System (INIS)

    Robert, J.; Raievski, V.

    1959-01-01

    The programme of the high flux laboratory pile EL3 was laid down in october 1954. It is a heavy-water moderated and cooled pile. The fuel rods are of uranium metal with 1.6 per cent - 2 per cent of molybdenum, with aluminium canning. The maximum thermal flux in the moderator is 10 14 n/cm 2 /s. Studies began in january 1955, construction in may 1955, and the first divergence took place in July 1957. This report gives a general description of the pile and its adjacent buildings, the physical study of the pile, and certain technological studies carried out for the construction of EL3. (author) [fr

  16. Windscale pile core surveys

    International Nuclear Information System (INIS)

    Curtis, R.F.; Mathews, R.F.

    1996-01-01

    The two Windscale Piles were closed down, defueled as far as possible and mothballed for thirty years following a fire in the core of Pile 1 in 1957 resulting from the spontaneous release of stored Wigner energy in the graphite moderator. Decommissioning of the reactors commenced in 1987 and has reached the stage where the condition of both cores needs to be determined. To this end, non-intrusive and intrusive surveys and sampling of the cores have been planned and partly implemented. The objectives for each Pile differ slightly. The location and quantity of fuel remaining in the damaged core of Pile 1 needed to be established, whereas the removal of all fuel from Pile 2 needed to be confirmed. In Pile 1, the possible existence of a void in the core is to be explored and in Pile 2, the level of Wigner energy remaining required to be quantified. Levels of radioactivity in both cores needed to be measured. The planning of the surveys is described including strategy, design, safety case preparation and the remote handling and viewing equipment required to carry out the inspection, sampling and monitoring work. The results from the completed non-intrusive survey of Pile 2 are summarised. They confirm that the core is empty and the graphite is in good condition. The survey of Pile 1 has just started. (UK)

  17. Processus ultra-rapides associés à la dynamique d'émission de la protéine GFP

    Science.gov (United States)

    Didier, P.; Guidoni, L.; Schwalbach, G.; Bigot, J.-Y.

    2002-06-01

    La protéine GFP (Green Fluorescent Protein) est un marqueur très efficace, utilisable en milieu vivant. La spectroscopie femtoseconde est particulièrement bien adaptée pour comprendre les mécanismes d'émission de cette protéine, étant donné la rapidité des processus de transfert mis en jeu. Nous-présentons des résultats sur la dynamique spectro-temporelle d'émission du mutant GFPuv résolue à l'échelle de la centaine de femtosecondes. Une transition Raman à 3300 cm^{-1} ainsi que la dynamique d'etablissement du gain avec un temps caractéristique d'environ 1.5 ps ont été mis en évidence.

  18. L’instabilité organisationnelle des districts industriels. Dynamiques des transformations internes d’un village de métier au nord du Viêt Nam The Organizational Instability of Industrial Districts: Dynamic Internal Transformations of a Craft Village in Northern Vietnam

    Directory of Open Access Journals (Sweden)

    Nguyen Quy Nghi

    2012-11-01

    Full Text Available Le village de métier est un sujet d’étude attractif, mais rarement traité comme une forme d’agglomération industrielle ou abordé sous l’angle de la sociologie industrielle. Le développement actuel des villages de métier montre bien la présence intensive des entreprises de tailles variées et l’implication d’autres acteurs en dehors du milieu de production (par exemple les autorités locales, le milieu de l’éducation. L’introduction d’acteurs nouveaux implique le changement des relations existantes, contribuant ainsi à la mise en place d’une nouvelle configuration. L’objectif de cet article est de montrer que l’organisation des villages de métier, qui est conçue comme un type de district industriel, est marquée par l’instabilité ou le changement permanent de la configuration générale, mais aussi par une transformation interne des acteurs au sein du district. À travers une étude de cas à Bát Tràng – un centre de production céramique au nord du Viêt Nam – cet article a pour objectif de montrer comment des entreprises familiales se réorganisent en structure plus formalisée, comment elles mobilisent du capital social pour régler leurs difficultés et les stratégies d’innovation qu’elles développent.Craft village is an attractive research subject, however it is rarely treated as a form of industrial agglomeration or studied from industrial sociology perspective. The current development of craft villages demonstrates the intensive presence of entreprises of all sizes and involvement of non productive actors (e.g. local authorities, education sector. The introduction of new actors therefore implies a change of existing relationships, contributing to the formulation of new configuration. The objective of this paper is to demonstrate that the organization of craft villages, as a type of industrial district, is marked by instability or permanent change in the overall configuration, but also by

  19. Piles of objects

    KAUST Repository

    Hsu, Shu-Wei; Keyser, John

    2010-01-01

    We present a method for directly modeling piles of objects in multi-body simulations. Piles of objects represent some of the more interesting, but also most time-consuming portion of simulation. We propose a method for reducing computation in many

  20. The reactor Cabri; La pile cabri

    Energy Technology Data Exchange (ETDEWEB)

    Ailloud, J.; Millot, J.P. [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1964-07-01

    exceptional circumstances... - experimental investigations on power excursions linked with precise initial conditions: the aim of this work is to define the basis for theoretical research, and the limits beyond which the risks of explosion cease to be negligible. The research work will be done so as to enable checking with outside reactor experiments and to continue them in the explosion field. - studies of the behaviour of the reactor control-instrumentation. - experimental investigations related with transient operation with initial short life (study of boiling, temperature measurements, vacuum pressure and fraction...) with the aim of defining the hypotheses of a theory on swimming-pool reactor kinetics related to heat transfer phenomena, - investigations of the behaviour of fuels in reactors (these experiments are planned to be carried out in loops) Preliminary experimental results. CABRI went critical on the 21 December 1963. The first transient experiments are expected for March 1964. (authors) [French] II devenait necessaire de construire en France une pile qui permette d'etudier les conditions de fonctionnement des installations futures, de choisir, tester et mettre au point les dispositifs de securite a adopter. On a choisi une pile a eau, type de pile qui correspond aux constructions les plus nouvelles du CEA en matiere de piles laboratoire ou d'universite; il importe en effet de pouvoir evaluer les risques presentes et d'etudier les possibilites d'augmentation de puissance constamment demandees par les utilisateurs: il est particulierement interessant d'eclaircir les phenomenes d'oscillation de puissance et les risques de calefaction (burn out). Les programmes de travaux sur CABRI seront harmonises avec les travaux effectues sur les Spert americains de meme type; lors de sa construction des contacts fructueux ont ete etablis avec les specialistes americains qui ont defini les premiers de ces reacteurs. La communication donne une

  1. Detection of tritium in the CO{sub 2} of the reactors G2/G3 using gas chromatography; La detection du tritium par chromatographie gazeuse dans le CO{sub 2} des piles G2/G3

    Energy Technology Data Exchange (ETDEWEB)

    Guillermin, P; Rossi, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    This gas-phase chromatographic method, based on the principle of the decomposition of a gas mixture into its pure constituents, makes it possible to identify and rapidly measure the tritium present in the heat-carrying fluid of the reactors G2/G3. The sensitivity limit corresponds to 5 x 10{sup -6} {mu}Ci/cm{sup 3} of tritiated gas, whereas the threshold reading of the D.C.C.A. is 10{sup -3} {mu}Ci/cm{sup 3} in the presence of {sup 41}A. This apparatus has interesting applications in the conditions where certain {beta} emitters (products of fission or of activation) interfere with the measurement of the tritium. It can easily be adapted to the detection of tritiated steam on condition that a reducing chemical treatment is applied for the atmospheric humidity. In fact, although this method is not as sensitive for the measurement of tritiated vapour as p-spectrometry in a scintillating medium, it may be set up very easily for measuring the C.M.A of tritium in air and is not affected by the presence of radio-active gases. (authors) [French] Cette methode de chromatographie en phase gazeuse, basee sur le principe de decomposition d'un melange gazeux en ses constituants purs, permet l'identification et la mesure rapide du tritium present dans le fluide caloporteur des piles G2/G3. La limite de sensibilite correspond a 5.10{sup -6} {mu}Ci/cm{sup 3} de gaz tritie, alors que le seuil de lecture du D.C.C.A. s'eleve a 10{sup -3} {mu}Ci/cm{sup 3} en presence de {sup 41}A. Cet appareillage presente un champ d'application interessant dans les domaines ou certains emetteurs {beta} (produits de fission ou d'activation) genent la mesure du tritium. Il peut s'adapter sans difficulte a la detection de la vapeur tritiee moyennant un traitement chimique reducteur de l'humidite atmospherique. En definitive, bien que cette methode ne soit pas aussi sensible pour la determination de la vapeur tritiee que la spectrometrie {beta} en milieu scintillant, elle permet de mesurer la C.M.A de

  2. Swimming-pool piles

    International Nuclear Information System (INIS)

    Trioulaire, M.

    1959-01-01

    In France two swimming-pool piles, Melusine and Triton, have just been set in operation. The swimming-pool pile is the ideal research tool for neutron fluxes of the order of 10 13 . This type of pile can be of immediate interest to many research centres, but its cost must be reduced and a break with tradition should be observed in its design. It would be an advantage: - to bury the swimming-pool; - to reject the experimental channel; - to concentrate the cooling circuit in the swimming-pool; - to carry out all manipulations in the water; - to double the core. (author) [fr

  3. Évolution des partis politiques dans le monde arabe | Page 4 | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Orient et en Afrique du Nord subir diverses mutations. Le soutien dont bénéficiaient les partis nationalistes a diminué au profit des partis islamistes. Ce sont ces derniers qui sont désormais les plus dynamiques et les plus contestataires des partis ...

  4. 173 Étude des performances épuratoires de la technique du ...

    African Journals Online (AJOL)

    Afrique Sciences

    à la station d'épuration de la ville d'Errachidia - Maroc. Chaouki HAMID1*, Lahcen ELWATIK1, Youssef RAMCHOUN2, Rachid FATH-ALLAH3,. Abdelrhafour AYYACH3, Zhor FATHALLAH4, Azzeddine EL MIDAOUI3 et El Mahdi HBAIZ5. 1Equipe des substances naturelles, synthèse et dynamique moléculaire, Faculté des ...

  5. Évolution des partis politiques dans le monde arabe | Page 2 | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Orient et en Afrique du Nord subir diverses mutations. Le soutien dont bénéficiaient les partis nationalistes a diminué au profit des partis islamistes. Ce sont ces derniers qui sont désormais les plus dynamiques et les plus contestataires des partis ...

  6. Epidémiologie de la furonculose des salmonidés.

    Directory of Open Access Journals (Sweden)

    DUBOIS-DARNAUDPEYS A.

    1977-04-01

    Full Text Available L'antagonisme bactérien dû à la flore d'accompagnement est le seul facteur jouant un rôle dans la dynamique des populations de A. salmonicida. L'action lytique des bactériophages ou de Bdellovibrio bacteriovorus est inactive sur cette bactérie.

  7. Évolution des partis politiques dans le monde arabe | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Orient et en Afrique du Nord subir diverses mutations. Le soutien dont bénéficiaient les partis nationalistes a diminué au profit des partis islamistes. Ce sont ces derniers qui sont désormais les plus dynamiques et les plus contestataires des partis ...

  8. Élaboration d'un guide de santé des forêts relatif à la décision du ...

    African Journals Online (AJOL)

    SARAH

    29 déc. 2014 ... plan de gestion de la forêt de la Mamora, pour la récolte .... Tableau 3 : Tendance de l'évolution du dépérissement des arbres de chaque placette de contrôle de 2011 à .... et des cycles endogènes de la dynamique des.

  9. Starting up a programme of atomic piles using compressed gas; Le demarrage d'un programme de piles atomiques a gaz comprime

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, J; Yvon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    1) An examination of the intellectual and material resources which have directed the French programme towards: a) the natural uranium and plutonium system, b) the use of compressed gas as heat transfer fluid (primary fluid). 2) The parts played in exploring the field by the pile EL2 and G1, EL2 a natural uranium, heavy water and compressed gas pile, G1 a natural uranium, graphite and atmospheric air pile. 3) Development of the neutronics of graphite piles: physical study of G1. 4) The examination of certain problem posed by centres equipped with natural uranium, graphite and compressed carbon dioxide piles: structure, special materials, fluid circuits, maximum efficiency. Economic aspects. 5) Aids to progress: a) piles for testing materials and for tests on canned fuel elements, b) laboratory and calculation facilities. 6) Possible new orientations of compressed gas piles: a) raising of the pressure, b) enriched fuel, c) higher temperatures, d) use of heavy water. (author) [French] 1) Examen des ressources - intellectuelles et materielles - qui ont oriente le programme fran is vers: a) la voie de l'uranium naturel et du plutonium; b) l'emploi comme fluide pour le transfert de la chaleur (fluide primaire) d'un gaz comprime. 2) Le role d'exploration des piles EL2 et G1, EL2 pile a uranium naturel, eau lourde et gaz comprime, G1 pile a uranium naturel, graphite et air atmospherique. 3) Developpement de la neutronique des piles a graphite: l'etude physique de G1. 4) Examen de certains problemes poses par les centrales equipees de piles a uranium naturel, graphite et gaz carbonique comprime: structure, materiaux speciaux, circuits de fluides, optimisation. Aspects economiques. 5) Les auxiliaires du progres: a) piles pour essai de materiaux et pour essais de cartouches, b) moyens de laboratoire et moyens de calcul. 6) Orientations nouvelles possibles des piles a gaz comprime: a) elevation de la pression, b) combustible enrichi, c) temperatures elevees, d) emploi de l

  10. Exploitation Agricole des Berges : Une Strategie D'Adaptation aux ...

    African Journals Online (AJOL)

    et socio-économique. ... dynamique des paysages agraires et son impact sur le capital naturel surtout sur les .... favoriser leur germination et amorcer leur croissance. ..... similaires ont été relevées au Bénin où l'impact humain se traduit par le ...

  11. Critical sizes and flux distributions in the shut down pile; Tailles critiques et cartes de flux a froid

    Energy Technology Data Exchange (ETDEWEB)

    Banchereau, A; Berthier, P; Genthon, J P; Gourdon, C; Lattes, R; Martelly, J; Mazancourt, R de; Portes, L; Sagot, M; Schmitt, A P; Tanguy, P; Teste du Bailler, A; Veyssiere, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    An important part of the experiments carried out on the reactor G1 during a period of shut-down has consisted in determinations of critical sizes, and measurements of flux distribution by irradiations of detectors. This report deals with the following points: 1- Critical sizes of the flat pile, the long pile and the uranium-thorium pile. 2- Flux charts of the same piles, and study of an exponential experiment. 3- Determination of the slit effect. 4- Calculation of the anisotropy of the lattice. 5- Description of the experimental apparatus of the irradiation measurements. (author) [French] Une part importante des experiences a froid effectuees sur le reacteur G1 a consiste en des determinations de tailles critiques et des mesures de distributions de flux par irradiations de detecteurs. Le present rapport traite les points suivants: 1- Tailles critiques de la pile plate, de la pile longue, de la pile a uranium-thorium. 2 - Cartes de flux des memes piles et etude d'une experience exponentielle. 3 - Determination de l'effet de fente. 4 - Calcul de l'anisotropie du reseau. 5 - Description de l'appareillage experimental des mesures d'irradiations. (auteur)

  12. Critical sizes and flux distributions in the shut down pile; Tailles critiques et cartes de flux a froid

    Energy Technology Data Exchange (ETDEWEB)

    Banchereau, A.; Berthier, P.; Genthon, J.P.; Gourdon, C.; Lattes, R.; Martelly, J.; Mazancourt, R. de; Portes, L.; Sagot, M.; Schmitt, A.P.; Tanguy, P.; Teste du Bailler, A.; Veyssiere, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    An important part of the experiments carried out on the reactor G1 during a period of shut-down has consisted in determinations of critical sizes, and measurements of flux distribution by irradiations of detectors. This report deals with the following points: 1- Critical sizes of the flat pile, the long pile and the uranium-thorium pile. 2- Flux charts of the same piles, and study of an exponential experiment. 3- Determination of the slit effect. 4- Calculation of the anisotropy of the lattice. 5- Description of the experimental apparatus of the irradiation measurements. (author) [French] Une part importante des experiences a froid effectuees sur le reacteur G1 a consiste en des determinations de tailles critiques et des mesures de distributions de flux par irradiations de detecteurs. Le present rapport traite les points suivants: 1- Tailles critiques de la pile plate, de la pile longue, de la pile a uranium-thorium. 2 - Cartes de flux des memes piles et etude d'une experience exponentielle. 3 - Determination de l'effet de fente. 4 - Calcul de l'anisotropie du reseau. 5 - Description de l'appareillage experimental des mesures d'irradiations. (auteur)

  13. Pile Driving Analysis for Pile Design and Quality Assurance

    Science.gov (United States)

    2017-08-01

    Driven piles are commonly used in foundation engineering. The most accurate measurement of pile capacity is achieved from measurements made during static load tests. Static load tests, however, may be too expensive for certain projects. In these case...

  14. Efficacité comparée des insecticides de natures différentes dans la ...

    African Journals Online (AJOL)

    SARAH

    gestion des insectes ravageurs du niébé au Centre du Bénin. 7695. Efficacité comparée .... basées sur la lutte biologique pour le contrôle de M. vitrata. Ces méthodes ..... Dynamique de la population de M. vitrata : La figure 1 illustre l'effet des ...

  15. Gestion des forêts domaniales en période de conflits : cas de la forêt ...

    African Journals Online (AJOL)

    Gestion des forêts domaniales en période de conflits : cas de la forêt classée du. Haut-Sassandra ... trois zones subi la même dynamique de déforestation pendant la période de conflits. .... partie Nord sous contrôle des groupements rebelles ...

  16. Study and modelling of the in-pile densification of the UO{sub 2} and MO{sub x} nuclear oxides; Etude et modelisation de la densification en pile des oxydes nucleaires UO{sub 2} et MO{sub x}

    Energy Technology Data Exchange (ETDEWEB)

    Boulore, A

    2001-03-01

    Amongst the many phenomena which take place in the course of the irradiation of UO{sub 2} or (U, Pu)O{sub 2} nuclear fuels, one of them involves the elimination of a fraction of the as-fabricated porosity. In-pile densification or sintering can reach 2.5%, i.e. approximately half the initial volume of pores is likely to disappear. Our literature survey indicates that the amplitude and kinetics of the phenomenon are both heavily dependent on the initial fuel microstructure. Micro-structural characterisation techniques of oxide fuels have therefore been developed in conjunction with quantitative image analysis methods. The ensuing methodology enables a quantitative comparison of micro-structural features in different fuels and has been applied to ascertaining the influence of the local fission rate and temperature on in-pile densification. It is thus revealed that in-pile operation eliminates a significant fraction of pores smaller than 3 microns in diameter. The experimental data generated has been used to set up a semi-empirical and a mechanistic model. The former is based on experimental results and is not essentially predictive. The inability of this model to predict the in-pile densification of oxide fuels is illustrated by the fact that the maximum fraction of pores that disappears is proportional to an empirical function of fission rate, and temperature. The proportionality factor appears to be difficult to correlate quantitatively to any given micro-structural feature. The model has however been applied to the interpretation of an in-pile densification experiment carried out in the Halden reactor (Norway). The latter model is mechanistic, i.e. it is based on the solution to a set of equations that describe the coupled temperature and radiation induced phenomena which occur in-pile. These can broadly be broken down into three categories: the fission fragment-pore interaction, the creation of point defects as the fission fragments slow down, and the diffusion

  17. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  18. Modelling the pile load test

    Directory of Open Access Journals (Sweden)

    Prekop Ľubomír

    2017-01-01

    Full Text Available This paper deals with the modelling of the load test of horizontal resistance of reinforced concrete piles. The pile belongs to group of piles with reinforced concrete heads. The head is pressed with steel arches of a bridge on motorway D1 Jablonov - Studenec. Pile model was created in ANSYS with several models of foundation having properties found out from geotechnical survey. Finally some crucial results obtained from computer models are presented and compared with these obtained from experiment.

  19. Laterally Loaded Piles in Clay

    DEFF Research Database (Denmark)

    Christensen, Helle; Niewald, Gitte

    1992-01-01

    The ultimate lateral resistance of a pile element moved horizontally can be analyzed by the theory of plasticity. At a certain depth the movements around the pile are purely horizontal and upper bound solutions can be estimated theoretically under undrained circumstances. Model tests...... in the laboratory show ultimate resistances close to the estimated limits and p - y curves close to curves based on test results from full-scale piles. Rough and smooth piles with circular and square cross sections are investigated....

  20. Modelling the pile load test

    OpenAIRE

    Prekop Ľubomír

    2017-01-01

    This paper deals with the modelling of the load test of horizontal resistance of reinforced concrete piles. The pile belongs to group of piles with reinforced concrete heads. The head is pressed with steel arches of a bridge on motorway D1 Jablonov - Studenec. Pile model was created in ANSYS with several models of foundation having properties found out from geotechnical survey. Finally some crucial results obtained from computer models are presented and compared with these obtained from exper...

  1. Characterizing hand-piled fuels

    Science.gov (United States)

    Clinton S. Wright; Paige C. Eagle; Cameron S. Balog

    2010-01-01

    Land managers throughout the West pile and burn surface fuels to mitigate fire hazard in dry forests. Whereas piling was historically conducted with heavy machinery following commercial harvesting operations, land managers are increasingly prescribing the use of hand piling and burning to treat surface fuels created by thinning and brush cutting. An estimate of the...

  2. Repenser la légitimité politique : inclusion des citoyens et médias ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Repenser la légitimité politique : inclusion des citoyens et médias sociaux numériques. Au Chili, une société civile dynamique et mobilisée se sert des nouvelles technologies numériques pour transformer les modes de participation à la vie politique. Ce projet de recherche consistera à recueillir des données sur la manière ...

  3. Molecular Dynamics Investigated by Neutron Scattering; Etude de la Dynamique Moleculaire au Moyen de la Diffusion des Neutrons; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 041e 0419 0414 0418 041d 0410 041c 0418 041a 0418 0421 041f 041e 041c 041e 0429 042c 042e 0420 0410 0421 0421 0415 042f 041d 0418 042f 041d 0415 0419 0422 0420 041e 041d 041e 0412 ; Estudio de la Dinamica Molecular por Dispersion Neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Janik, J. A. [Institute for Nuclear Physics, Cracow (Poland)

    1965-06-15

    is discussed from the point of view of molecular dynamics. (author) [French] L'auteur fait le point de l'etat actuel des connaissances touchant le probleme de l'applicabilite des theories de Krieger- Nelkin et de Griffing dans le cas des gaz. Ensuite, sur la base d'experiences faites avec du methane liquide, il examine d'une maniere critique l'applicabilite du concept du tenseur de masse a des molecules dans l'etat condense. Les arguments les plus puissants qui militent contre l'application de la theorie de Krieger-Nelkin aux etats condenses sont: a) un deplacement dans la distribution des neutrons en energie, apres diffusion, vers les grandes energies; b) l'absence d'une relation de dependance entre la fraction inelastique et l'angle de diffusion. D'autres parties du memoire traitent de la dynamique de rotation des groupes ammonium dans les composes d'ammonium. L'auteur discute la plupart des donnees d'experience relatives aux halogenures d'ammonium en se fondant sur les experiences de differents auteurs. Far des mesures de neutrons, il a obtenu une liberte de rotation des groupes NH{sub 4} pour certaines substances, tandis que pour d'autres la rotation evolue en vibration de torsion. Dans le dernier cas, il a compare les frequences des vibrations de torsion obtenues par divers auteurs au cours d'experiences sur les neutrons avec celles qui resultent de la spectroscopie infrarouge et des mesures de la chaleur specifique. L'auteur discute egalement l'obstacle qui s'oppose a l'evaluation de la rotation a l'aide de mesures des sections efficaces totales pour les neutrons. En outre, il compare la dynamique de rotation des groupes NH{sub 4} dans NH{sub 4}ClO{sub 4} et des groupes H{sub 3}O dans H{sub 3}OCIO{sub 4}, en se fondant sur des experiences de diffusion inelastique des neutrons. Il a obtenu une rotation libre du groupe NH4 dans le perchlorate d'ammonium, meme a des temperatures ne depassant pas celle de l'azote liquide. Pour H{sub 3}OCIO{sub 4} il a obtenu une

  4. Discovery: Pile Patterns

    Science.gov (United States)

    de Mestre, Neville

    2017-01-01

    Earlier "Discovery" articles (de Mestre, 1999, 2003, 2006, 2010, 2011) considered patterns from many mathematical situations. This article presents a group of patterns used in 19th century mathematical textbooks. In the days of earlier warfare, cannon balls were stacked in various arrangements depending on the shape of the pile base…

  5. Test Exponential Pile

    Science.gov (United States)

    Fermi, Enrico

    The Patent contains an extremely detailed description of an atomic pile employing natural uranium as fissile material and graphite as moderator. It starts with the discussion of the theory of the intervening phenomena, in particular the evaluation of the reproduction or multiplication factor, K, that is the ratio of the number of fast neutrons produced in one generation by the fissions to the original number of fast neutrons, in a system of infinite size. The possibility of having a self-maintaining chain reaction in a system of finite size depends both on the facts that K is greater than unity and the overall size of the system is sufficiently large to minimize the percentage of neutrons escaping from the system. After the description of a possible realization of such a pile (with many detailed drawings), the various kinds of neutron losses in a pile are depicted. Particularly relevant is the reported "invention" of the exponential experiment: since theoretical calculations can determine whether or not a chain reaction will occur in a give system, but can be invalidated by uncertainties in the parameters of the problem, an experimental test of the pile is proposed, aimed at ascertaining if the pile under construction would be divergent (i.e. with a neutron multiplication factor K greater than 1) by making measurements on a smaller pile. The idea is to measure, by a detector containing an indium foil, the exponential decrease of the neutron density along the length of a column of uranium-graphite lattice, where a neutron source is placed near its base. Such an exponential decrease is greater or less than that expected due to leakage, according to whether the K factor is less or greater than 1, so that this experiment is able to test the criticality of the pile, its accuracy increasing with the size of the column. In order to perform this measure a mathematical description of the effect of neutron production, diffusion, and absorption on the neutron density in the

  6. Tritiated Thymidine as Tracer in DNA Metabolism and Cell Dynamics of Experimental Myeloid Leukaemia; Emploi de la Thymidine Tritiee comme Indicateur pour l'Etude du Metabolisme de l'ADN et de la Dynamique des Cellules dans la Leucemie Myeloide Experimentale; 0422 0440 0438 0442 0414 ; Empleo de la Timidina Tritiada como Indicador para Estudiar el Metabolismo del Acido Desoxirribonucleico y la Dinamica Celular en la Leucemia Mieloide Experimental

    Energy Technology Data Exchange (ETDEWEB)

    Zajicek, G.; Rosin, A.; Gross, J. [Department of Experimental Medicine and Cancer Research, Hebrew University, Hadassah Medical School, Jerusalem (Israel)

    1962-02-15

    increased with the increase of the concentration of the TH{sup 3} administered. After an incubation period which lasted 120 min no labelled mitosis was found. Further, the incorporation pattern was the same whether the label was added at the beginning of the incubation or after 160 min. Addition of TH{sup 3} to the same suspension at various time intervals did not alter the per cent of labelled cells but the number of grains per nucleus rose after every administration of the TH{sup 3}. Not all the cells in the suspension incorporated the same amount of TH{sup 3}. Quantitative measurements were made including grain counts, and the results showed that there is probably a deficiency of thymidine available to the leukaemic cells in their ascitic fluid. The dichotomy between the synthesis of the full complement of DNA and subsequent division of the cell will be discussed. (author) [French] En Israeel, le tritium a ete utilise comme indicateur isotopique pour l'etude de divers problemes biologiques. Les auteurs rendent compte des resultats d'experiences dans lesquelles ils ont employe la thymidine tritiee pour suivre la dynamique cellulaire dans la leucemie myeloiede experimentale ainsi que pour explorer le mecanisme de son incorporation a l'ADN des cellules leucemiques et des cellules eosinophiles de tumeurs ascitiques. Les cellules leucemiques ont ete marquees in vivo chez des rats par injection de thymidine tritiee dans la veine jugulaire. La dose etait de 1 {mu}c/g. Les auteurs ont evalue la vitesse de l'apparition des cellules marquees dans le sang peripherique et dans la tumeur ascitique. Au cours d'autres experiences, ils ont determine la vitesse de dilution de l'indicateur dans les noyaux, ce qui a permis d'evaluer le temps de doublement cellulaire dans la population de myelocites. Les auteurs ont etudie la dynamique des cellules leucemiques transfusees en injectant des myelocites marques dans la veine jugulaire de rats normaux et de rats leucemiques. Ils ont mesure la

  7. Reheating experiment in the 35-ton pile; Experience de rechauffage sur la pile de 35 tonnes

    Energy Technology Data Exchange (ETDEWEB)

    Cherot, J; Girard, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    When the 35-ton pile was started up it was necessary for us, in order to study certain effects (xenon for example), to know the anti reactivity value of the rods as a function of their dimensions. We have made use of the possibility, in the reheating experiment, of raising the temperature of the graphite-uranium block by simple heating, in order to determine the anti reactivity curves of the rods, and from that the overall temperature coefficient. For the latter we have considered two solutions: first, one in which the average temperature of the pile is defined as our arithmetical mean of the different values given by the 28 thermocouples distributed throughout the pile; a second in which the temperature in likened to a poisoning and is balanced by the square of the flux. The way in which the measurements have been made is indicated, and the different instruments used are described. The method of reheating does not permit the separation of the temperature coefficients of uranium and of graphite. The precision obtained is only moderate, and suffers from the changes of various parameters necessary to other manipulations carried out simultaneously (life time modulators for example), and finally it is a function of the comparatively restricted time allowed. It is evident of course that more careful stabilisation at the different plateaux chosen would have necessitated long periods of reheating. (author) [French] Nous avions besoin lors de la montee en puissance de la pile de 35 tonnes, pour l'elude de divers effets (xenon par ex.) de la valeur de l'antireactivite des barres en fonction de leurs cotes. Nous avons profite dans l'experience rechauffage de la possibilite de monter en temperature, non nucleairement, le bloc graphite uranium, pour determiner les courbes d'antireactivite des barres et de la le coefficient global de temperature. Nous avons considere pour ce dernier deux solutions. Une premiere dans laquelle la temperature moyenne de la pile est definie comme

  8. Présentation du texte de Georges Balandier « Phénomènes sociaux totaux et dynamique sociale »

    Directory of Open Access Journals (Sweden)

    Liliane Voyé

    2008-10-01

    Full Text Available Introduction et mise en perspective du texte de Georges Balandier « Phénomènes sociaux totaux et dynamique sociale », initialement publié dans les Cahiers Internationaux de Sociologie, volume 30, 1961, pp. 23-34. Reproduit avec l’aimable autorisation des Cahiers Internationaux de Sociologie.Presentation of Georges Balandier’s text « Total social phenomenon and social dynamism »Introduction and contextualization of the Georges Balandier’s article « Phénomènes sociaux totaux et dynamique sociale » first published in the Cahiers Internationaux de Sociologie, volume 30, 1961, pp. 23-34 and reprinted with the kind authorization of the revue.Presentación del trabajo de Georges Balandrier "Hecho social total y dinámica social"Introducción y análisis del texto de Georges Balandrier « Phénomènes sociaux totaux et dynamique sociale », publicado por primera vez en los Cahiers Internationaux de Sociologie, volumen 30, 1961, pp. 23-34. Con la amable autorización de los Cahiers Internationaux de Sociologie.

  9. Mono pile foundation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lyngesen, S.; Brendstrup, C.

    1997-02-01

    The use of mono piles as foundations for maritime structures has been developed during the last decades. The installation requirements within the offshore sector have resulted in equipment enabling driving of piles up to 3-4 m to large penetration depths. The availability of this equipment has made the use of large mono piles feasible as foundations for structures like wind turbines. The mono pile foundations consists of three parts; the bare pile, a conical transition and a boat landing. All parts are prefitted at the yard in order to minimise the installation work that has to be carried out offshore. The study of a mono pile foundations for a 1.5 MW wind turbine has been conducted for two locations, Horns Rev and Roedsand. Three different water depths: 5, 8 and 11 m have been investigated in the study. The on-site welding between pile and conical transition is performed by an automatic welding machine. Final testing and eventually repair of the weld are conducted at least 16 hours after welding. This is followed by final installation of J-tube, tie-in to subsea cables and installation of the impressed current system for corrosive protection of the mono pile. The total cost for procurement and installation of the mono pile using the welded connection is estimated. The price does not include procurement and installation of access platform and boat landing. These costs are estimated to 250.000 DKK. Depending on water depth the cost of the pile ranges from 2,2 to 2,7 million DKK. Procurement and fabrication of the pile are approx. 75% of the total costs. The remaining 25% are due to installation. The total costs are very sensitive to the unit price of pile steel. During the project it became obvious that ice load has a very large influence on the dimensions of the mono pile. (EG)

  10. The influence of xenon poisoning in high-flux reactors on the choice of control rod speeds (1961); Influence de l'empoisonnement xenon dans les piles a haut flux sur le choix de la vitesse des barres de controle (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    - The general laws are restated concerning the changes in xenon and iodine concentrations in thermal neutron reactors, assuming an uniform neutron flux distribution in the core. It is shown how the evolution in the xenon poisoning influences the selection of the control rod speed, at start-up. Certain simple methods of calculation are developed making it possible to resolve the problem of the choice of this speed in the case where the xenon poisoning is taken into account. (author) [French] - On rappelle les lois generales relatives aux evolutions de concentration xenon et iode dans les piles atomiques a neutrons thermiques lorsqu'on suppose une repartition uniforme du flux de neutrons dans le coeur. On montre comment l'evolution de l'empoisonnement xenon influe sur le choix de la vitesse des barres de controle en periode de demarrage. On developpe certaines methodes de calculs simples permettant de resoudre le probleme du choix de la vitesse des barres de controle, dans le cas ou l'on tient compte de l'empoisonnement xenon. (auteur)

  11. Gestion de l'énergie d'un système hybride pile à combustible/batterie basée sur la commande optimale

    Directory of Open Access Journals (Sweden)

    M. N. SID

    2015-03-01

    Full Text Available Ce papier traite de l'optimisation de gestion de l'énergie électrique dans un véhicule hybride (pile à combustible/batterie, afin de minimiser autant que possible la consommation de l'hydrogène avec le maintien de l'état de charge de la batterie. Premièrement, on présente les sources d'énergies utilisées dans cette étude, la modélisation du système hybride, le choix de type des convertisseurs d'électronique de puissance utilisés et le dimensionnement de ces éléments.Deuxièmement on traite le problème d'optimisation sous contraintes basée sur le principe du minimum de Pontriaguine en introduisant la fonction Hamiltonienne de la commande optimale.Cette stratégie a été évaluée dans un environnement de simulation sous Matlab/Simulink utilisant quatre cycles de conduite standards.Une étude comparative en terme de consommation d'hydrogène a été faite avec deux autres stratégies la première dite thermostat qui est une stratégie très simple basée sur les contraintes imposées par les sources, la seconde approche consiste à utiliser un filtre passe-bas à la sortie de la puissance demandée afin de respecter les contraintes en dynamique sur la source principale. La stratégie traitée présente une bonne amélioration de la consommation d'hydrogène en adoptant une bonne stratégie de gestion de l'énergie électrique dans le système hybride.

  12. The influence of the form of the cells on the buckling and fine structure of the thermal flux in a heterogeneous pile; Influence de la forme des cellules sur le laplacien et structure fine du flux thermique dans une pile heterogene

    Energy Technology Data Exchange (ETDEWEB)

    Bailly du Bois, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    The elementary diffusion equation and the age equation have been solved for lattices assumed, to be infinite and periodic. In this way the influence of the form of the cells on thermal captures and resonance captures is determined. The solutions obtained are expressed by means of tabulated functions which can be used in the analysis of the f factor measurements. The case of mixed lattices in which different types of rods are regularly arranged is also foreseen. (author) [French] L'equation elementaire de la diffusion et l'equation de l'age ont ete resolues pour des reseaux supposes infinis et periodiques. On determine ainsi quelle est l'influence de la forme des cellules sur les captures thermiques et les captures de resonances. Les solutions obtenues s'expriment au moyen de fonctions tabulees qui peuvent etre utilisees dans le depouillement des mesures du facteur f. Le cas des reseaux mixtes dans lequels des barreaux de types differents sont disposes regulierement est egalement envisage. (auteur)

  13. 93 une urbanisation linéaire, dynamique demographique et ...

    African Journals Online (AJOL)

    Mohand

    d'Alger, dans l'ensemble Sahel-Mitidja sur un linéaire côtier de 2 km. Rattaché administrativement à la daira de ... connait une dynamique démographique remar- quable, dans sa périphérie orientale - composé de l'ensemble Sahel-. Mitidja ..... «Etude agro-pédologique de la plaine de la Mitidja». Florin B.; Semoud N. 2010.

  14. Etude Du Comportement Dynamique D'un Systeme De Pompage ...

    African Journals Online (AJOL)

    SIMULINK le comportement dynamique d'un système de pompage composé d'un générateur photovoltaïque, d'un onduleur, d'un moteur à induction et d'une pompe centrifuge. Le modèle global du système est bouclé : la sortie tension du GPV est ...

  15. 212 Analyse de la dynamique des pâturages autour des ouvrages ...

    African Journals Online (AJOL)

    Ali B. Béchir

    hommes et de leurs troupeaux dictés par les conditions climatiques [2]. Ainsi ... Plusieurs études sur les pâturages sahéliens [3,4] ont montré une dégradation .... global de qualité spécifique aux différentes espèces herbacées recensées.

  16. Analyse de la dynamique des pâturages autour des ouvrages ...

    African Journals Online (AJOL)

    The dynamics are characterized by the proliferation of Acaciatortilis and Balanites aegyptiaca due to the movement of animals and ancestry of Cenchrus biflorus and Schoenefeldia gracilis on other herbaceous species. However, livestock wells do not pose a threat to the future production of these spaces because they ...

  17. Power Split Strategy for Fuel Cell Hybrid Electric System Stratégie de séparation des flux de puissance pour un système électrique hybride à pile à combustible

    Directory of Open Access Journals (Sweden)

    Di Domenico D.

    2009-11-01

    Full Text Available The power management of a hybrid system composed of a fuel cell, a battery and a DC/DC power converter is developed. A decoupled control strategy is proposed, aimed at balancing the power flow between the stack and the battery and avoiding electrochemical damage due to low oxygen concentration in the fuel cell cathode. The controller is composed of two components. The first controller regulates the compressor, and as a consequence the oxygen supplied to the cathode, via a classic Proportional-Integral controller. The second controller optimally manages the current demanded by the fuel cell and battery via a linear-quadratic control strategy acting on the converter. An Extended Kalman Filter is also designed in order to estimate the battery State of Charge. The closed-loop performance was tested in simulation using a 310th-order system model. Ce papier illustre une stratégie de gestion de puissance pour un système hybride composé d’une pile à combustible, d’une batterie et d’un convertisseur DC/DC. Dans le but d’équilibrer les flux de puissance entre la pile à combustible et la batterie et d’éviter les dégâts causés par une dépression d’oxygène dans le cathode de la pile, un contrôleur découplé est proposé. Ce contrôleur se compose de deux parties. La première, un régulateur proportionnel-intégral, commande le compresseur et, par conséquent, le flux d’oxygène fourni au cathode. La deuxième, un régulateur linéaire-quadratique, gère le courant demandé par la pile à combustible et la batterie. Pour estimer l’état de charge de la batterie, un filtre de Kalman étendu a aussi été conçu. Les performances de la stratégie ont été analysées en simulation avec un modèle de batterie du 310e ordre.

  18. Efficiency of the Shut-Down and Safety Equipment and the Kinetic Characteristics of the G2 and G3 Reactors; Efficacite des dispositifs de secours et de securite et caracteristiques cinetiques des piles G2 et G3; Ehffektivnost' sistem avarijnoj zashchity reaktorov G.2 i G.3 i kineticheskie kharakteristiki ehtikh sistem; Caracteristicas cineticas y eficacia de los dispositivos de auxilio y de seguridad de los reactores G2 y G3

    Energy Technology Data Exchange (ETDEWEB)

    Henri, C.; Plisson, J.; Teste duBailler, A. [Centre d' Etudes Nucleaires de Saclay (France)

    1963-10-15

    The experience gained in several years of operating the G2 and G3 reactors confirms that natural uranium-graphite-gas reactors are extremely safe. The built-in shut-down and safety mechanisms which minimize operational incidents such as lack of power from the mains, blower failure, lack of water etc., together with accidents such as cladding bursts, local overheating, loss of coolant etc. are described and their operation explained by means of diagrams. The main points examined are as follows: (a) power distribution and controlability during accident conditions; (b) distribution of emergency water; and (c) the safety chain. The performance of the installations and the successive improvements incorporated in them are mentioned. The built-in safety characteristics of the reactors are shown by means of an experimental study of their behaviour in transient operation. These studies make it possible to check the validity of the calculation model. The machine calculation programmes can subsequently be used to study the consequences of possible accidents. Special attention is given to the depressurization accident, taking into account the performance of the safety device installed. (author) [French] L'experience acquise'au cours de plusieurs annees d'exploitation des piles G2 et G3 permet de confirmer le haut degre de securite du fonctionnement des piles de la filiere uranium naturel-graphitegaz. Les installations fixes de secours et de securite permettant de pallier, d'une part aux incidents d'exploitation tels que manque d'alimentation du reseau de distribution, arret de soufflage, manque d'alimentation en eau, etc., d'autre part, a des accidents tels que rupture de gaine, echauffements locaux, perte de fluide caloporteur, etc., sont decrites et leur fonctionnement explicite au moyen de schemas de principe. On examine principalement (a) la distribution ''puissance'' et ''controle'' des installations secourues, (b) la distribution d'eau secourue, et (c) la chaine de

  19. Use of geothermal piles combined with pile foundations

    Directory of Open Access Journals (Sweden)

    Ivan Kuzytskyi

    2016-07-01

    Full Text Available The possibility of use of geothermal piles in conditions of cold climate is considered. Full-scale experiment is conducted for using this technology in Kiev. Obtained results testify about a possibility for using the system in conditions of Ukraine, but this technology requires more detailed study and simulation of multiannual cycle of use of geothermal piles 

  20. Apport de la simulation numérique à la compréhension des mécanismes d'interaction de cavités dans le cadre de la modélisation de l'endommagement ductile sous sollicitation dynamique

    Science.gov (United States)

    Roy, G.; Buy, F.; Llorca, F.

    2002-12-01

    L'étude présentée s'inscrit dans le cadre d'une démarche menant à la construction d'un modèle analytique ou semi analytique de comportement élasto-visco-plastique endommageable, applicable aux chargements rencontrés en configuration d'impact violent et générant de l'écaillage ductile. La prise en compte des effets de compressibilité et de micro inertie est essentielle pour modéliser la phase de croissance. Des simulations numériques globales de la structure et locales à l'échelle des hétérogénéités permettent d'évaluer les niveaux de sollicitations dans les zones susceptibles de s'endommager, dévaluer des critères analytiques de germination de l'endommagement et de comprendre les mécanismes d'interaction entre les défauts. Les effets micro inertiels et de compressibilité sont ainsi mis en évidence dans les phases de germination et de coalescence des micro défauts. II s'agit ici d'une illustration non exhaustive de travaux engagés au CEA Valduc sur le tantale, dans le cadre d'une thèse [10]. Un programme matériaux en partenariat CEA-CNRS sur la modélisation multi échelles du comportement de structures a également été initié dans ce contexte.

  1. Statistical fluctuations of the number of neutrons in a pile; Fluctuations statistiques du nombre de neutrons dans une pile

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The theory of the statistical fluctuations in a pile is extended to the space dependent case, and gives the fluctuations of the number of neutrons in a cell of the core or reflector of the pile. This number changes through elementary processes occurring at random, which are, capture, source, fission and scattering. Of all these processes, fission is the only one which changes more than one neutron at a time and so is responsible of the deviation of the fluctuations from a Poisson law. The importance of this deviation depends on the dimensions of the cell compared to the slowing down length. When the dimensions are small, the fluctuations close to a Poisson law. (author) [French] La theorie des fluctuations statistiques est etendue au cas local et donne les fluctuations du nombre de neutrons dans une cellule situee dans le coeur ou le reflecteur de la pile. Ce nombre evolue au cours du temps sous l'influence de phenomenes aleatoires qui sont la capture, la diffusion, les sources et les neutrons secondaires de fission. L'emission simultanee de plusieurs neutrons distingue ce phenomene des precedents qui n'affectent qu'un neutron individuellement. L'importance de ce phenomene sur la loi de fluctuation depend des dimensions de la cellule par rapport a la longueur de ralentissement. Quand ces dimensions sont petites, le caractere particulier de ce phenomene disparait. (auteur)

  2. Évolution qualitative et quantitative des composantes de l'œuf ...

    African Journals Online (AJOL)

    SARAH

    28 févr. 2014 ... contrôle de coquille et de calibre dans les fermes. Mots clés : œuf, pondeuse, ... dynamique qualitative des composantes de l'œuf . Certains auteurs ont ... programme de conduite et de gestion d'élevage. Élevées en bande ...

  3. 149 Résumé Notre article se propose d'analyser le travail des ...

    African Journals Online (AJOL)

    8 juil. 2008 ... ... la dynamique de l'économie informelle, c'est le rapport à la loi qui est décisif… » ... qui très souvent, pour ne pas dire systématiquement, attire le con- sensus chez ceux qui .... des secteurs modernes…» (A.Invernizzi.

  4. 'Dynamique sociale et mutations dans le système de gestion du foncier en zone de savane. Une réflexion à partir des villages baoulé d'Allokro, Kouakro, Mandéké et Sahounty (Côte d'Ivoire'

    Directory of Open Access Journals (Sweden)

    Babo, A.

    2005-01-01

    Full Text Available 'Interaction between Water Supply and Demand in Two Collective Irrigation Schemes in North-East Brazil'. Des études de champ ont été conduites de 1995 à 1996 dans la savane nord-guinéenne du Nigeria afin de déterminer les réponses de 22 génotypes de soja à une infestation par Alectra. Des différences significatives ont été observées entre les génotypes de soja quant au nombre de pousses d'Alectra émergées à 9 et 10 semaines après semis et au nombre de jours à la première émergence d'Alectra. L'émergence d'Alectra a été retardée sur les génotypes de soya à maturité précoce (54 jours après semi, tandis que pour les variétés à maturité plus tardive, Alectra a émergé déjà à partir de 50 jours après semis. Seize génotypes ont montré une faible infestation, parfois inexistante, d'Alectra tandis que les six autres étaient fortement parasités. Les génotypes de soja fortement infestés par les pousses d'Alectra ont enregistré des rendements inférieurs aux autres variétés. Cependant, SAMSOY2 et TGX1485-ID qui ont supporté une infestation relativement forte d'Alectra ont montré des rendements proches des génotypes peu ou non infestés d'Alectra. Nos résultats suggèrent trois mécanismes possibles de résistance au parasitisme d'Alectra parmi les génotypes de soja. Les seize génotypes peu ou non infestés de pousses Alectra pourraient avoir produit une quantité insignifiante d'exsudats de racines nécessaires pour la stimulation de la germination des graines d'Alectra. SAMSOY et TGX1485-1D qui ont donné un rendement élevé malgré l'importante infestation d'Alectra montreraient ainsi une tolérance au parasite.

  5. Pulse pile-up IV

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1991-05-01

    The study of pulse pile-up is extended from the case of unipolar pulses, for which ruin theory is an excellent approximation, to the case of bipolar pulses for which ruin theory is not applicable to the effect of the back-kicks in reducing the pile-up: an appropriate solution is presented. (Author) 3 refs., 11 figs

  6. Grouting for Pile Foundation Improvement

    NARCIS (Netherlands)

    Van der Stoel, A.E.C.

    2001-01-01

    The aim of this research was to examine the use of grouting methods for pile foundation improvement, a generic term that is used here to define both foundation renovation (increasing the bearing capacity of a pile foundation that has insufficient bearing capacity) and foundation protection

  7. Settlement during vibratory sheet piling

    NARCIS (Netherlands)

    Meijers, P.

    2007-01-01

    During vibratory sheet piling quite often the soil near the sheet pile wall will settle. In many cases this is not a problem. For situations with houses, pipelines, roads or railroads at relative short distance these settlements may not be acceptable. The purpose of the research described in this

  8. Theoretical and experimental study of a calorimetric technique for measuring energy deposition in materials caused by complex pile irradiation; Etude theorique et experimentale d'une technique calorimetrique de mesure des depots d'energie dans les materiaux dus au rayonnement complexe de pile

    Energy Technology Data Exchange (ETDEWEB)

    Mas, P; Sciers, P; Droulers, Y [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires, 38 - Grenoble (France)

    1962-07-01

    Calorimetric methods may be used to measure gamma fluxes greater than 10{sup 6} r/h near the cores of swimming pool reactors. The theory, design, and properties of isothermal calorimeters are discussed, and experimental results obtained with two types are presented. Measurement of energy deposition in materials and the long term integration of energy depositions are other uses of these devices. Results of measurements on heat deposition in steel and water are given. Fluxes were also measured. (authors) [French] Une premiere partie traite de la theorie des calorimetres isothermes mis en oeuvre au C.K.N. Grenoble. La puissance deposee dans le calorimetre par les flux de rayonnement echauffe celui-ci. L'echauffement est mesure a l'aide d'un thermocouple. On montre que l'on a ainsi une mesure absolue de cette puissance. Une deuxieme partie traite de l'etude experimentale de: deux types d'appareils utilises: leur construction, les resultats experimentaux, leurs utilisations. Trois de celles-ci sont particulierement interessantes: - la mesure des hauts flux gamma, - la mesure du depot d'energie dans les materiaux, - l'integration pendant une longue duree des depots d'energie (un modele de calorimetre a fonctionne a ce jour 2 500 heures et a integre 9 x 10 puissance 10 rads gamma et 6 x 10 puissance 18 neutrons rapides). La troisieme partie est consacree a l'etude des qualites de l'appareil: robustesse, fidelite, precision, sensibilite, gamme de mesure. Enfin dans la derniere partie sont decrites deux applications de la methode calorimetrique a la mesure du depot d'energie dans un acier special et dans l'eau. (auteurs)

  9. 373 Inventaire des mouches hématophages dans les élevages ...

    African Journals Online (AJOL)

    zinga

    3Ecole Régionale Post-Universitaire d'Aménagement et de gestion Intégrés des Forêts ... invitent à élaborer une stratégie de lutte et de contrôle des vecteurs pour un ..... l'activité journalière, de la dynamique spatio-temporelle, les préférences ...

  10. La dévalorisation des filles au Bangladesh : continuité ou changement

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le déséquilibre du ratio hommes-femmes se concentre en grande partie dans des ... le contrôle masculin du travail et des ressources de la famille en vertu d'un ... à savoir qu'une meilleure compréhension de la dynamique du changement qui a ... IWRA/CRDI sur les changements climatiques et la gestion adaptive de l'eau.

  11. Numerical modeling of centrifuge cyclic lateral pile load experiments

    Science.gov (United States)

    Gerolymos, Nikos; Escoffier, Sandra; Gazetas, George; Garnier, Jacques

    2009-03-01

    To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in Laboratoire Central des Ponts et Chaussées. Three types of cyclic loading were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flight density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using a cyclic nonlinear Winkler spring model, which describes the full range of inelastic phenomena, including separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing a wide variety of monotonic and cyclic experimental p-y curves. The physical meaning of key model parameters is graphically explained and related to soil behavior. Comparisons with the centrifuge test results demonstrate the general validity of the model and its ability to capture several features of pile-soil interaction, including: soil plastification at an early stage of loading, “pinching” behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and strength changes due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. (1974) for sand, is also presented.

  12. Dynamique des savoirs et des échanges d’un produit de collecte en territoire transfrontalier Dinâmicas de conhecimentos e trocas de uma fruta de palmeira numa região fronteiriça. O caso do açaí (Euterpe oleracea Mart. na região do baixo Oiapoque Dynamics of knowledge and exchanges of a non timber forest product in border territory. The case of açai (Euterpe oleracea Mart. in the Lower Oyapock

    Directory of Open Access Journals (Sweden)

    Laval Pauline

    2012-11-01

    Full Text Available Le palmier wassaï (Euterpe oleracea Mart., aussi appelé açaí au Brésil et pinot en Guyane, est natif du bassin amazonien, en Amérique du Sud. Dans cette région, il est d’une importance alimentaire majeure. En effet, on peut tirer de ses fruits un nectar très riche qui constitue une part importante de la consommation de certains peuples d’Amazonie, notamment pendant la période de fructification du palmier. Ce nectar est désormais à la mode en milieu urbain au Brésil, et s’exporte sous une large gamme de produits dérivés à l’international, grâce à ses vertus énergétiques et anti-oxydantes reconnues. Si la majeure partie de la production et de la transformation de wassaï se déroule à Belém, dans l’Etat du Pará au Brésil, de nombreuses autres filières existent à plus petite échelle, car le fruit comme le nectar, très périssables, supportent mal le transport. Cet article explicite la filière de production du nectar de wassaï du bas Oyapock, région frontalière entre la Guyane française et le Brésil. Nous étudions, du point de vue de l’ethnoécologie, les impacts de la frontière sur la dynamique des savoirs et des échanges du wassaï. Plus de 100 entretiens semi-directifs ont été menés chez les différents groupes ethniques du bas Oyapock, ainsi que des travaux d’observation participante de localisation des zones de croissance du wassaï, et un lexique spécialisé trilingue a été réalisé. Les résultats révèlent une très grande diversité de savoirs, de savoir-faire et d’usages de ce palmier, parmi les 9 groupes ethniques recensés dans la région. Ces usages sont le plus souvent spécifiques à chaque groupe, et en perte de vitesse, sauf la consommation de nectar, qui est commune à tous les groupes ethniques, en augmentation générale. Les savoirs et techniques consacrés à la domestication et à la préparation du nectar sont explicités. Dans le but de comprendre la répartition du

  13. Synthèse des approches probabilistes de la Life Time Value et premières propositions d'extension

    OpenAIRE

    Herbert Castéran

    2004-01-01

    La recherche marketing s’est longtemps caractérisée par son approche statique des comportements et attitudes des clientèles. Elle offre classiquement une analyse de ceux-ci pouvant conduire, dans les meilleurs cas, à une segmentation des publics. Toutefois elle éprouve des difficultés à se situer dans des approches résolument dynamiques. Audelà de méthodes sans réel fondement, la principale option retenue, pour ce faire, est celle des modèles économétriques (modèles de choix discrets, modèles...

  14. Impact du comportement vibratoire et acoustique des joints de portes et de vitrages sur le bruit d'origine aérodynamique

    OpenAIRE

    Oliver , Clara; Jézéquel , Louis; Besset , Sébastien; VAN HERPE , François; Abbadi , Zouhir

    2015-01-01

    International audience; Dans la modélisation des joints de portes et de vitrages pour la prédiction du bruit aérodynamique il est nécessaire de sortir du domaine classique du calcul vibro-acoustique linéaire, en raison du caractère fortement non-linéaire des joints. La déformation lors de la fermeture des portes ou vitres provoque des modifications des raideurs statique et dynamique, de l'amortissement et de la transparence acoustique des joints. Ensuite les efforts aérodynamiques modifient c...

  15. Study of the {rho}-bar, {beta}-bar and {lambda} parameters of a light-water reactor; Etude des parametres {rho}-bar, {beta}-bar et {lambda} d'une pile a eau legere

    Energy Technology Data Exchange (ETDEWEB)

    Riche, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-09-01

    The kinetic and perturbation equations are derived from the time-dependent transport equation. Kinetic equations depend only on the ratios a = {rho}-bar/{beta}-bar and b = {beta}-bar/{lambda}, which are definite, while the reactivity {rho}-bar, the delayed neutron fraction ({beta}-bar and the generation time {lambda} are expressed in terms of an arbitrary function I. The 'static' definitions of these parameters, which reduce kinetic problems to a set of purely term dependent equations, introduce the effective fraction {beta}-bar. One way of determining experimentally the ratio b is presented; it consists in analysing the power transient after a rapid variation of the reactivity, caused by the implosion of an empty glass-bull. A simple interpretation is proposed. The apparatus can be transformed easily into a reactimeter. The value of the effective delayed neutron fraction {beta}-bar has been determined by averaging the reactivity effects of a copper sheet through out the reactor core. Experimental results: b = {beta}-bar/{lambda} = 129 s{sup -1} and {beta}-bar 795.10{sup -5}, have been determined on a light-water moderated, enriched-uranium fuelled reactor. The calculated values of the effectiveness of delayed neutrons {gamma} {beta}-bar/{beta} 1.23 and the generation time {lambda} 59.10{sup -6}s agrees fairly well with the experimental results. (author) [French] Les equations de la cinetique et de la perturbation sont deduites de la theorie du transport, par l'intermediaire de la 'notion' d'importance des neutrons. La cinetique ne depend que des rapports a = {rho}-bar/{beta}-bar et b = {beta}-bar/{lambda}, qui sont parfaitement definis; par contre, la reactivite {rho}-bar, la proportion de neutrons retardes {beta}-bar et le temps de generation des neutrons prompts {lambda} s'expriment a l'aide d'une meme fonction arbitraire I. Les definitions 'statiques' de ces parametres, qui permettent de rendre compte de la

  16. Study of the {rho}-bar, {beta}-bar and {lambda} parameters of a light-water reactor; Etude des parametres {rho}-bar, {beta}-bar et {lambda} d'une pile a eau legere

    Energy Technology Data Exchange (ETDEWEB)

    Riche, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-09-01

    The kinetic and perturbation equations are derived from the time-dependent transport equation. Kinetic equations depend only on the ratios a = {rho}-bar/{beta}-bar and b = {beta}-bar/{lambda}, which are definite, while the reactivity {rho}-bar, the delayed neutron fraction ({beta}-bar and the generation time {lambda} are expressed in terms of an arbitrary function I. The 'static' definitions of these parameters, which reduce kinetic problems to a set of purely term dependent equations, introduce the effective fraction {beta}-bar. One way of determining experimentally the ratio b is presented; it consists in analysing the power transient after a rapid variation of the reactivity, caused by the implosion of an empty glass-bull. A simple interpretation is proposed. The apparatus can be transformed easily into a reactimeter. The value of the effective delayed neutron fraction {beta}-bar has been determined by averaging the reactivity effects of a copper sheet through out the reactor core. Experimental results: b = {beta}-bar/{lambda} = 129 s{sup -1} and {beta}-bar 795.10{sup -5}, have been determined on a light-water moderated, enriched-uranium fuelled reactor. The calculated values of the effectiveness of delayed neutrons {gamma} {beta}-bar/{beta} 1.23 and the generation time {lambda} 59.10{sup -6}s agrees fairly well with the experimental results. (author) [French] Les equations de la cinetique et de la perturbation sont deduites de la theorie du transport, par l'intermediaire de la 'notion' d'importance des neutrons. La cinetique ne depend que des rapports a = {rho}-bar/{beta}-bar et b = {beta}-bar/{lambda}, qui sont parfaitement definis; par contre, la reactivite {rho}-bar, la proportion de neutrons retardes {beta}-bar et le temps de generation des neutrons prompts {lambda} s'expriment a l'aide d'une meme fonction arbitraire I. Les definitions 'statiques' de ces parametres, qui permettent de rendre compte de la cinetique par des equations dependant purement du

  17. Seismic response of pile foundations and pile forces caused by kinematic and inertial interaction

    International Nuclear Information System (INIS)

    Hartmann, H.G.; Waas, G.

    1985-01-01

    The horizontal motion and pile forces of pile groups subjected to earthquake excitation are analysed. The piles are modelled as linear elastic beam elements embedded in a layered linear visco-elastic soil medium. Pile-soil-pile interaction is included. The earthquake excitation results from vertically propagating shear waves. Kinematic and inertial interaction effects on foundation motion and pile forces are studied for a single pile, a small pile group and a large pile group. Soft and stiff soil conditions are considered, and the effect of a flexible vs. a rigid halfspace below the soil layers is shown. (orig.)

  18. 40 CFR 264.554 - Staging piles.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Staging piles. 264.554 Section 264.554... for Cleanup § 264.554 Staging piles. This section is written in a special format to make it easier to... staging pile? A staging pile is an accumulation of solid, non-flowing remediation waste (as defined in...

  19. Test Pile Reactivity Loss Due to Trichloroethylene

    International Nuclear Information System (INIS)

    Plumlee, K.E.

    2001-01-01

    The presence of trichloroethylene in the test pile caused a continual decrease in pile reactivity. A system which removed, purified, and returned 12,000 cfh helium to the pile has held contamination to a negligible level and has permitted normal pile operation

  20. ÉTUDE DE CAS — Pérou : Des défenseurs du marché équitable ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    16 déc. 2010 ... Une politique de recrutement dynamique menée à l'intérieur et à l'extérieur ... permis d'établir le modèle de la stratégie de plaidoyer de l'INDECOPI. ... tels que des organismes de la société civile, des juges et des entreprises.

  1. Eléments de théorie des graphes

    CERN Document Server

    Bretto, Alain; Hennecart, François

    2012-01-01

    Ce livre est une introduction d velopp e la th orie des graphes. Autour de cette th orie se d veloppe aujourd'hui l'un des domaines les plus f conds et les plus dynamiques des mah matiques et de l'informatique. La th orie des graphes permet de r pr senter un ensemble complexe d'objets en exprimant les relations entre les l ments: r seaux de communication, circuits lectriques, etc. Le livre pr sente le langage et les notions l mentaires de cette th orie, les diff rents types de graphes (bipartis, arbres, arborescences, graphes eul riens et hamiltoniens, etc.); il tudie les relations entre les g

  2. De l'importance des orbites periodiques: Detection et applications

    Science.gov (United States)

    Doyon, Bernard

    L'ensemble des Orbites Periodiques Instables (OPIs) d'un systeme chaotique est intimement relie a ses proprietes dynamiques. A partir de l'ensemble (en principe infini) d'OPIs cachees dans l'espace des phases, on peut obtenir des quantites dynamiques importantes telles les exposants de Lyapunov, la mesure invariante, l'entropie topologique et la dimension fractale. En chaos quantique (i.e. l'etude de systemes quantiques qui ont un equivalent chaotique dans la limite classique), ces memes OPIs permettent de faire le pont entre le comportement classique et quantique de systemes non-integrables. La localisation de ces cycles fondamentaux est un probleme complexe. Cette these aborde dans un premier temps le probleme de la detection des OPIs dans les systemes chaotiques. Une etude comparative de deux algorithmes recents est presentee. Nous approfondissons ces deux methodes afin de les utiliser sur differents systemes dont des flots continus dissipatifs et conservatifs. Une analyse du taux de convergence des algorithmes est aussi realisee afin de degager les forces et les limites de ces schemes numeriques. Les methodes de detection que nous utilisons reposent sur une transformation particuliere de la dynamique initiale. Cette astuce nous a inspire une methode alternative pour cibler et stabiliser une orbite periodique quelconque dans un systeme chaotique. Le ciblage est en general combine aux methodes de controle pour stabiliser rapidement un cycle donne. En general, il faut connaitre la position et la stabilite du cycle en question. La nouvelle methode de ciblage que nous presentons ne demande pas de connaitre a priori la position et la stabilite des orbites periodiques. Elle pourrait etre un outil complementaire aux methodes de ciblage et de controle actuelles.

  3. The Windscale piles - past, present and future

    International Nuclear Information System (INIS)

    Jones, J.M.; Adams, A.L.

    1987-01-01

    The paper concerns the Windscale reactor piles, in which a fire occurred in the core of pile 1 thirty years ago. A description is given of the two Windscale piles, along with the events leading up to the accident, and the state of the piles following shutdown. The surveillance and maintenance to ensure that the pile and associated buildings were in a safe condition is outlined. The present state of the core, water ducts and pile chimneys is described. The present and future programme of work to ensure long term safety is discussed. This includes the initial steps in decommissioning of the piles. (U.K.)

  4. Piles of dislocation loops in real crystals

    International Nuclear Information System (INIS)

    Dubinko, V.I.; Turkin, A.A.; Yanovskij, V.V.

    1985-01-01

    Behaviour of piles of dislocation loops in crystals was studied in order to define metal swelling under irradiation. Energy of pile interaction with point defects and intrinsic pile energy are studied in the framework of the linear elasticity theory. Preference of dislocation pile calculated in the paper decreases with radiation dose hence, material swelling rate also decreases. Creation of conditions, which assume an existence of piles of dislocation loops being stable under irradiation, is of particular interest

  5. Contribution to the study and use of ionisation chambers for nuclear reactor control (1965); Contribution a l'etude et a l'utilisation des chambres d'ionisation pour le controle des reacteurs nucleaires (1965)

    Energy Technology Data Exchange (ETDEWEB)

    Duchene, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-02-15

    high-power reactors. (author) [French] Les chambres d'ionisation sont actuellement les detecteurs les mieux adaptes au controle des reacteurs nucleaires par des mesures neutroniques. Nous avons cru bon de rappeler quelques generalites concernant la dynamique des reacteurs, les differents procedes de detection des neutrons, le fonctionnement des chambres d'ionisation et les methodes de mesure utilisees. Notre contribution aux techniques de controle des reacteurs consiste d'une part en une tentative de synthese des facteurs intervenant dans le fonctionnement des chambres d'ionisation, l'etude de ces facteurs, et d'autre part l'elaboration de chambres d'ionisation a fission et a bore permettant de suivre la marche d'un reacteur du demarrage jusqu'a la puissance maximale. Dans le domaine des chambres a fission, nous avons en particulier ameliore les techniques de depot d'oxyde d'uranium sur l'aluminium et realise la mise au point de depots par electrolyse sur d'autres metaux: acier inoxydable, cuivre, molybdene, nickel, tantale, titane, kovar, tungstene et beryllium. Nous avons elabore plusieurs types de chambres a fission servant au demarrage des reacteurs: un type de performances moyennes actuellement utilise dans les piles francaises un type a haute sensibilite un type a haute temperature qui a fonctionne jusqu'a 600 deg. C. En ce qui concerne les chambres a bore, nous avons etudie les perturbations apportees dans les mesures par l'exposition des chambres a d'importants flux de neutrons et a un rayonnement {gamma} intense. Cette exposition produit une modification des proprietes des materiaux constitutifs et la production dans les chambres d'un bruit de fond qui peut gener considerablement les mesures neutroniques. Nous avons montre que la technique de compensation permettait de limiter l'importance de ce bruit de fond et d'augmenter ainsi la plage de fonctionnement des chambres d'ionisation classiques destinees aux mesures de puissance. Enfin, nous avons realise deux

  6. Underwater noise reduction of marine pile driving using a double pile.

    Science.gov (United States)

    2015-12-01

    Impact pile driving of steel piles in marine environments produces extremely high sound levels in the water. : It has been shown that current pile driving noise attenuation techniques, such as bubble curtains and : cofferdams, provide limited noise r...

  7. Gouvernance de l’eau potable et dynamiques locales en zone rurale au Bénin

    Directory of Open Access Journals (Sweden)

    Bernard G. Hounmenou

    2006-05-01

    écision ainsi que la participation des communautés à l’investissement et à la gestion des points d’eau. La concrétisation de cette volonté d’améliorer les systèmes d’alimentation en eau potable se traduit par exemple, par l’adhésion des communautés à travers leurs contributions financières à la réalisation des ouvrages et la mise en place de structures de gestion chargées de l’entretien et de la maintenance de ces derniers. Les structures de gestion ont entre autres tâches, de mobiliser la participation financière des populations à la construction des ouvrages, de fixer le prix de l’eau, de choisir les vendeurs et de gérer la maintenance des équipements. La nouvelle stratégie se traduit aussi par l’entrée dans le système local lié à la gouvernance de l’eau potable en zone rurale, de nouveaux acteurs tels que les collectivités locales (les nouvelles communes, les ONG, les entreprises du secteur privé et les organisations d’usagers d’eau, qui ont un fonctionnement assez proche de celui des entreprises sociales. A partir d’éléments empiriques, cet article se focalise sur les analyses liées aux dynamiques socio-économiques des acteurs impliqués dans le processus d’approvisionnement en eau des populations rurales au Bénin.In populations’ basic service supplying, the public policies, especially those of developing countries, have met deep changes in the last recent years. The most important changes are relative to the withdrawal of gratuitous public service. Beside the fundamental necessity of states to clean their economies, those reforms aim to favour populations’ participation in the management of operations linked to their needs satisfaction. The participation question constitutes actually a major element, for services organisation at community level. Indeed, several experiences have shown that the projects realised without the concerned populations’ participation, have failed at the execution moment, or by the lack

  8. Typologie et dynamique forestières: Un exemple en Barousse (Hautes Pyrénées

    Directory of Open Access Journals (Sweden)

    Mazars, Jacqueline

    1996-12-01

    Full Text Available An ecological analysis of the Pyrenean beech groves (Barousse points to hydric conditions as the main factor determining different ecological units on a same geological substratum. This approach, completed by the historical research that brings to light the manmade actions in the fir elimination of this area, can in part generate the knowledge of the real potential forestry (Fir-Beech, Fir. The structural analysis of stands, disturbed in the past by overexploitation, indicates that the upper stratum has closed, and that, often through pioneer phases, these woods have extended their area.

    [fr] L'analyse phytoécologique de hêtraies des Pyrénées Centrales (Barousse montre que ce sont surtout les variations des conditions hydriques qui déterminent, sur un même substrat colluvial, les différentes unités stationnelles observées. Cette approche, complétée par des études historiques 'mettant en lumière le déterminisme anthropique de la disparition presque totale du Sapin de cette région, permet, en partie, de connaître les potentialités forestières réelles (hêtraiesapinière, sapinière. L'analyse structurale des peuplements, anciennement ouverts par surexploitation, indique une fermeture généralisée du couvert et une dynamique d'extension de ces formations souvent par l'intermédiaire de phases pionnières.

  9. Experimental measurement of neutron spectrum in the reflector of a light water reactor; Determination experimentale du spectre des neutrons dans le reflecteur d'une pile a eau legere

    Energy Technology Data Exchange (ETDEWEB)

    Brethe, P [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1963-09-15

    1. Thermal neutrons: The temperature of the thermal neutron spectrum was calculated using Au-Lu foils. This temperature varies from 300 deg. K (temperature of the moderator) at 30 cm of the core to 350 deg. K in a hole of the core. 2. Slowing down of neutron: Four resonance detectors have been used (Au, In, Co, Mn). We can write a 1/E form of the spectrum. The linking up energy E{sub M} between thermal neutron spectrum and slowing down spectrum is about 0.23 eV and is free from the Maxwell spectrum temperature. The decrease of slowing down flux regarding thermal flux, farther from the core, has been showed. 3. Fast neutrons: We used 3 threshold detectors (Ni, Al, Mg). We supposed a E{sup 1/2} e{sup -{beta}}{sup E} from of the spectrum above 3 MeV. The values of {beta} are in a range from 0.775, at the centre of the core and in a loop-hole, to 0,64 at about 30 cm of the core. 4. Continuous shape of the spectrum: The following interpolations give useful informations between the field where measurements have been made: between 340 eV and 10 keV: 1/E form between 10 keV and 330 keV: 1/(E {sigma}{sub S}(E)) form ({sigma}{sub S}(E) elastic scattering section on hydrogen) between 330 keV and 3 MeV: calculated form by the moments method (ref. BSR). (author) [French] 1. Neutrons thermiques: La temperature du spectre des neutrons thermiques a ete determinee par la methode (or-lutecium). Cette temperature varie de 300 deg. K (temperature du moderateur) a 30 cm du coeur, a 350 deg. K dans une encoche du coeur. 2. Neutrons en ralentissement: 4 detecteurs resonnants ont ete employes (Au, In, Co, Mn). Le spectre peut etre mis sous la forme 1/E quelle que soit la distance a la limite coeur-reflecteur. L'energie de raccordement E{sub M} entre spectre des neutrons thermiques et spectre en ralentissement est environ 0,23 eV et independante de la temperature du spectre de Maxwell. La diminution relative du flux en ralentissement par rapport au flux thermique quand la distance au coeur

  10. Diversité et succession des protistes dans l'océan Arctique

    OpenAIRE

    Terrado, Ramon

    2011-01-01

    L'Arctique est la région du globe où le réchauffement climatique est le plus prononcé. L'étude de la diversité des microorganismes, leur dynamique de communauté et les facteurs environnementaux qui agissent sur eux s'avèrent donc importants pour comprendre comment ces communautés vont réagir à des changements environnementaux. Cette thèse explore la diversité des protistes et leur dynamique dans l'océan Arctique sur une échelle temporelle ainsi que spatiale. La méthodologie utilisée dans cett...

  11. Prévision avec des copules en finance

    OpenAIRE

    Charpentier , Arthur

    2015-01-01

    Cet article présente un survol les techniques usuelles de modélisation de séries nancières multiples. Pus spéciquement, on cherchera a obtenir une extention multivariée des modèles GARCH. Dans un premier temps, nous verrons comment modéliser la dynamique de la matrice de corrélation (conditionnelle), puis nous verrons comment généraliser cette approche à des lois conditionnelles plus générales, construites à l'aide de copules (et s'aranchir ainsi de l'hypothese de lois elliptiques). Les princ...

  12. Energy piles. A fundamental energy pile; Energiepfaehle. Eine fundamentale Energiequelle

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Holger; Beldermann, Nico [GF-Tec GmbH, Roedermark (Germany)

    2013-03-01

    The Maintower, the new airport in Berlin/Brandenburg, a lot of Ikea buildings, and also small office buildings or residential buildings may exchange energy with the underground by means of pile fundaments. At the correct planning and execution, energy piles are low-cost geothermal power plants which sustainable generate heating and cooling for the buildings standing on them. Even more energy can be generated safely under compliance with the groundwater protection by means of a new development of the material and the transfer.

  13. Stability of Slopes Reinforced with Truncated Piles

    Directory of Open Access Journals (Sweden)

    Shu-Wei Sun

    2016-01-01

    Full Text Available Piles are extensively used as a means of slope stabilization. A novel engineering technique of truncated piles that are unlike traditional piles is introduced in this paper. A simplified numerical method is proposed to analyze the stability of slopes stabilized with truncated piles based on the shear strength reduction method. The influential factors, which include pile diameter, pile spacing, depth of truncation, and existence of a weak layer, are systematically investigated from a practical point of view. The results show that an optimum ratio exists between the depth of truncation and the pile length above a slip surface, below which truncating behavior has no influence on the piled slope stability. This optimum ratio is bigger for slopes stabilized with more flexible piles and piles with larger spacing. Besides, truncated piles are more suitable for slopes with a thin weak layer than homogenous slopes. In practical engineering, the piles could be truncated reasonably while ensuring the reinforcement effect. The truncated part of piles can be filled with the surrounding soil and compacted to reduce costs by using fewer materials.

  14. Développement d'un modèle ostéoarticulaire du genou humain pour une analyse dynamique du contact en grands déplacements

    OpenAIRE

    Bideau , Nicolas; Dao , T.T.; Rassineux , Alain; Ho Ba Tho , Marie-Christine

    2011-01-01

    National audience; Le principal objectif de ce travail est le développement d'un modèle tridimensionnel de l'articulation du genou en grands déplacements. A partir des données d'imagerie médicale (IRM), un modèle géométrique 3D a été développé. Ce modèle est résolu par la méthode des éléments finis. La simulation proposée permet de comprendre le comportement dynamique des différentes structures articulaires lors d'un mouvement de grande amplitude.

  15. Dynamique de la population de la cigogne blanche ( Ciconia ...

    African Journals Online (AJOL)

    Ce travail porte sur l'analyse des paramètres démographiques de la cigogne blanche en lgérie, à partir des données de trois ecensements nationaux effectués en 1995, 1998 et 001. Un délai de trois années entre un recensement et un autre a été dopté pour voir par apport à la tendance évolutive des effectifs des couples ...

  16. Pile oscillator measurements of thermal absorption cross sections of Al, Mg, Fe and Cu; Mesure des sections efficaces thermiques d'absorption de l'Al, du Mg, du Fe et du Cu par la methode d'oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Carre, J C; Vidal, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The phase oscillation technique used at ZOE has the property of reducing of a marked factor the effect of neutron scattering by the sample. The absorption cross sections of poorly absorbing and highly scattering materials have been measured; for neutrons of 2,200 m/s, the following values are obtained: 229 {+-} 3 mb for Al; 64.2 {+-} 1.5 mb for Mg, 2.53 {+-} 0.03 b for Fe and 3.74 {+-} 0.04 b for Cu. (authors) [French] La methode d'oscillation de phase utilisee a ZOE possede la propriete de diminuer d'un facteur important l'influence de la diffusion. Les sections efficaces de capture de materiaux peu capturants et tres diffusants, ont ete mesurees; pour des neutrons de 2200 m/s, on obtient pour l'Al: 229 {+-} 3mb, pour le Mg: 64,2 {+-} 1,5 mb, pour le Fe: 2,53 {+-} 0,03 b et pour le Cu: 3,74 {+-} 0,04 b. (auteurs)

  17. Characterizing Axial Stiffness of Individual Batter Piles with Emphasis on Elevated, Laterally Loaded, Clustered Pile Groups

    Science.gov (United States)

    2016-11-01

    using the appropriate stiffness based on the direction of the calculated pile load. 1...load cases. CPGA utilizes the stiffness method (Saul 1968) of three-dimensional pile group analysis for user-specified static loadings. The pile...CPGA analysis and coordinate systems (global and pile) As discussed in Chapter 1, the CPGA software utilizes the stiffness method (Saul 1968) of

  18. Analysis of pile foundations under dynamic loads

    International Nuclear Information System (INIS)

    Waas, G.; Hartmann, H.G.

    1981-01-01

    A method is presented for the analysis of pile foundations which are subjected to horizontal dynamic loads from earthquakes, airplane impact, gas explosion or other sources. The motion of the pile cap and the pile forces are computed. - The loads may be applied to the pile cap or directly to the piles (e.g. by earthquake wave motion). The soil may be stratified and is considered to be an elastic or visco-elastic medium. The piles are assumed vertical. The method makes use of an approximate fundamental solution for displacements caused by a dynamic point load in a layered visco-elastic medium. The approximation involves a discretization of the medium in the vertical direction. In horizontal directions the medium is treated by continuum theory. The soil medium supports each pile at about 10 to 20 nodes. A dynamic flexiblity matrix for the soil is derived which relates the elastic, damping and inertial forces of the soil to the displacements at each node. It includes effects of radiation damping. All piles are coupled through the soil flexibility matrix. The piles are modelled by beam elements. Transient response is computed using fast discrete Fourier transforms. The arrangement of the piles is arbitrary. However, simple and double symmetry can be accounted for by the computer program. When the pile arrangement is axisymmetric, the degrees of freedom can be reduced to only those of two piles per ring. The influence of the number of piles and the influence of the pile spacing on group stiffness and on pile forces is presented for two soil profiles. Dynamic effects on pile forces of a foundation for a reactor building are studied. They are significant when soils are soft. (orig.)

  19. Pile load test on large diameter steel pipe piles in Timan-Pechora, Russia

    Energy Technology Data Exchange (ETDEWEB)

    McKeown, S. [Golder Associates Inc., Houston, TX (United States); Tart, B. [Golder Associates Inc., Anchorage, AK (United States); Swartz, R. [Paragon Engineering Services Inc., Houston, TX (United States)

    1994-12-31

    Pile load testing conducted in May and June of 1993 at the Polar Lights Ardalin project in Arkangelsk province, Russia, was documented. Pile load testing was conducted to determine the ultimate and allowable pile loads for varying pile lengths and ground temperature conditions and to provide creep test data for deformation under constant load. The piles consisted of 20 inch diameter steel pipe piles driven open ended through prebored holes into the permafrost soils. Ultimate pile capacities, adfreeze bond, and creep properties observed were discussed. 10 figs., 4 tabs.

  20. La diffusion spatiale des technologies de l'information géographique en France

    Directory of Open Access Journals (Sweden)

    Stéphane Roche

    1999-03-01

    Full Text Available La diffusion des technologies de l'information géographique sur le territoire français s'inscrit dans les modèles classiques «centre-périphérie» de diffusion des innovations technologiques. Pourtant, au-delà de ces grandes dynamiques nationales, la distribution spatiale des TIG reflète les caractéristiques institutionnelles, culturelles et spatiales spécifiques d'un secteur géomatique en plein développement.

  1. DRIVEN POLYSTRONG REINFORCED CONCRETE PILES AND NEW DESIGN OF PILE CAPS

    Directory of Open Access Journals (Sweden)

    I. I. Bekbasarov

    2015-01-01

    Full Text Available The paper presents constructional and technological features for manufacturing driven piles with variable strength of pile shaft. Economical efficiency of their production has been shown in the paper. The paper provides a pile cap design that ensures perception of hammer impacts with the help of lateral edges of the pile cap. Driven reinforced concrete piles which are manufactured from three shaft sections having various strength have been proposed in the paper. Material strength (concrete grade and diameter of bars and length of shaft sections are given on a case by case basis in accordance with nature and rate of stresses in piles during their driving process. Manufacturing of polystrong piles provides an opportunity to select them for a particular construction site with due account of their preservation during driving process.A pile cap has been developed that as opposed to existing analogous designs makes it possible to transmit impact efforts from a hammer to the pile through lateral surface of its head part. The pile cap provides the possibility to increase an area for perception of hammer impact efforts by the pile and in doing so it is possible significantly to reduce a damage risk and destruction of pile concrete during its driving. Application of polystrong piles and their driving with the help of new pile cap are considered as a basis for defect-free and resource-saving technology for pile foundations in the construction.

  2. Pullout capacity of batter pile in sand.

    Science.gov (United States)

    Nazir, Ashraf; Nasr, Ahmed

    2013-03-01

    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21-31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18-75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  3. Screw piles for cold climate foundations

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R.; Sakr, M. [Almita Manufacturing Ltd., Edmonton, AB (Canada)

    2008-07-01

    Almita Manufacturing is an Alberta-based company that designs and builds screw piles with its own installation teams. It also engineers and supplies piles to numerous other companies and independent installers. The company services industries such as oil and gas; power transmission and distribution; and commercial construction. This presentation discussed the design and technical aspects of screw piles. A screw pile was defined as a steel pipe shaft with a 45 degree cut at the bottom and a formed helical plate welded to the outside of the pipe near the base and at a selected point on the shaft. The pile is screwed into the ground with a planetary drive head of suitable torque rating. The helical plate or helix helps facilitate the installation of the pile and gives the screw pile increased bearing capacity and pull-out resistance over a traditional straight-shaft pile. Screw piles were compared against cast in place concrete piles and steel driven piles. Screw piles were reported to have no tailings; no concrete curing time; no rebar, anchor belts, and no liners; and no dewatering. Screw piles can also be installed in all types of weather. Rhe Cree Burn Camp case study near Fort McMurray, Alberta was also presented. This residential camp and recreation complex consists of pre-fabricated units that make up three storey housing buildings and a single floor multi-use building. The case study provided information on soil; design parameter inputs; load testing program and pile configuration; geotechnical and structural design results; compression load test arrangement; pile test setup; and test results. The presentation also discussed fabrication as well as installation equipment. Various applications were also presented through a series of project pictures. Last, the presentation provided a simple cost analysis. tabs., figs.

  4. Pullout capacity of batter pile in sand

    Directory of Open Access Journals (Sweden)

    Ashraf Nazir

    2013-03-01

    Full Text Available Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  5. Fiabilité des structures mécaniques adaptatives: effet de la panne des actionneurs ou des capteurs sur la stabilité

    Science.gov (United States)

    Fall, H.; Charon, W.; Kouta, R.

    2002-12-01

    Ces dernières décennies, des activités significatives dans le monde étaient dirigées autour du contrôle actif. Le but de ces recherches était essentiellement d'améliorer les performances, la fiabilité et la sécurité des systèmes. Notamment dans le cas des structures soumises à des vibrations aléatoires. D'importants travaux ont été consacré à l'utilisation des “matériaux intelligents” comme capteurs et actionneurs. Cette article propose l'analyse de la fiabilité des systèmes mécaniques en étudiant les pannes des actionneurs ou des capteurs. L'effet de ces pannes sur la stabilité et la performance du système y est démontré. Les méthodologies de conception y sont rappelées. Des exemples numériques sont fournis à travers le contrôle d'un panneau sous chargement dynamique pour illustrer la méthode proposée.

  6. Pile Load Capacity – Calculation Methods

    Directory of Open Access Journals (Sweden)

    Wrana Bogumił

    2015-12-01

    Full Text Available The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.

  7. Introduction to Single Piles under Lateral Loading

    DEFF Research Database (Denmark)

    Augustesen, Anders; Ibsen, Lars Bo

    .2). The description is based on results of laboratory tests, full-scale field tests as well as numerical investigations presented in literature. Second, general methods that attempt to model lateral pile response are discussed in section 1.4. Third, focus is paid to a widely used method for prediction of the response......The purpose of this chapter is to give a short introduction to single piles subjected to lateral loading. First, the observed behaviour of laterally loaded piles is described, i.e. the effects of loading conditions, installation procedure, pile type etc. on pile behaviour are presented (section 1...... of a lateral loaded pile, namely the Winkler approach in which the pile is modelled as an elastic beam on an elastic foundation (section 1.5). The soil response and thereby the elastic foundation is represented by springs with nonlinear behaviour (p-y curves). In section 1.6 different types and formulations...

  8. Multisignal detecting system of pile integrity testing

    Science.gov (United States)

    Liu, Zuting; Luo, Ying; Yu, Shihai

    2002-05-01

    The low strain reflection wave method plays a principal rule in the integrating detection of base piles. However, there are some deficiencies with this method. For example, there is a blind area of detection on top of the tested pile; it is difficult to recognize the defects at deep-seated parts of the pile; there is still the planar of 3D domino effect, etc. It is very difficult to solve these problems only with the single-transducer pile integrity testing system. A new multi-signal piles integrity testing system is proposed in this paper, which is able to impulse and collect signals on multiple points on top of the pile. By using the multiple superposition data processing method, the detecting system can effectively restrain the interference and elevate the precision and SNR of pile integrity testing. The system can also be applied to the evaluation of engineering structure health.

  9. Dynamique de changement de l’arganeraie entre sur-usage et mutations sociales : une opportunité d’équilibre socio-écologique ?

    Directory of Open Access Journals (Sweden)

    Farid El Wahidi

    2014-12-01

    agit dans une première étape, d’estimer le rythme et connaître le type de dégradation des forêts. La seconde étape, consiste à relier les estimations de ces dynamiques de changement à des facteurs précis issus de l’analyse des modes de gestion coutumière et aux dynamiques démographiques, sociales et économiques dans la zone d’étude. Les résultats obtenus permettent de préciser le discours ambigu autour de la dégradation de l’arganeraie, du moins celle de montagne, le long de la bande atlantique. Ils impliquent un faible rythme de régression de la surface forestière ne dépassant guère un taux de 0.2 % entre 1993 et 2006. Quant à la densité des souches, elle décline de moins d’une cépée (en moyenne 0.61 à l’ha sur 22 ans. Ces changements, le plus souvent ponctuels, sont observés essentiellement (96.5 % en domaine commun (mouchaa à usage libre échappant au règlement de la gestion coutumière imposé par la communauté riveraine. L’arganeraie des Haha connaît une dynamique de changement à long terme corollaire d’une dynamique démographique, sociale et économique supposée favorable à sa préservation. Néanmoins, elle souffre d'une dégradation qualitative de ses individus et d’un dysfonctionnement des processus naturels contraignant toute dynamique d’autoréparation écologique et rendant discutable la fiabilité et la durabilité de la forêt paysanne.

  10. International dosimetry experiment on the zero power pile of the Boris Kidric Institute at Vinca (Yugoslavia) (1961); Experience internationale de dosimetrie sur la pile de puissance nulle de l'Institut Boris Kidric de Vinca (Yougoslavie) (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Weill, J; Furet, J; Baillet, J; Donvez, G; Duchene, J; Gras, R; Mercier, R [Commissariat a l' Energie Atomique, Section Autonome d' Electronique des Reacteurs, Saclay (France). Centre d' Etudes Nucleaires; Chenouard, J; Lecomte, J [Commissariat a l' Energie Atomique, Dept. de Physico - Chimie, Service des Isotopes Stables, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    On the occasion of the international dosimetry experiment on the zero power pile of the Yugoslavian Atomic Energy Centre at Vinca, the Commissariat a l'energie Atomique had agreed to prepare the measurement and security equipment and see to the manipulation of the heavy water, and in addition was responsible for the operation and the starting up of the pile during the experiment. The measurement and security apparatus, developed at Saclay and installed on the pile for low and high pressure runs, is listed, together with the safety equipment added near the control room. The various operations and manipulations carried out on the pile are described: filling with heavy water, starting up, determination of the critical level, testing the efficiency of the rods, operating the pile during the experiments. By operating to a carefully planned schedule, the experiments were, finished before the date fixed by the International Atomic Agency. (authors) [French] Dans le cadre de l'experience internationale de dosimetrie sur la pile de puissance nulle du Centre d'Etudes Nucleaires Yougoslave de Vinca, le Commissariat a l'Energie Atomique avait accepte de preparer l'equipement de controle et de securite, de pourvoir a la manipulation de l'eau lourde de la pile et avait la responsabilite de son fonctionnement et de sa mise en marche pendant l'experience. On enumere ici l'appareillage de controle et de securite installe sur la pile pour les marches a basse et haute puissances, appareillage mis au point a Saclay, ainsi que les protections ajoutees a proximite de la salle de controle. On decrit les differentes manipulations et operations effectuees sur la pile: remplissage d'eau lourde, demarrage, recherche du niveau critique, verification de l'efficacite des barres, conduite de la pile pendant les experiences. Grace a un planning tres serre qui a pu etre tenu, les experiences ont pu etre terminees avant la date prevue par l'Agence Atomique Internationale. (auteurs)

  11. Analysis on pile testing results of post-grouting bored pile

    Science.gov (United States)

    Zheng, A. R.

    2017-04-01

    Based on static load test results, the bearing capacity of bored piles with pile-toe and pile-shaft post-grouting has been analyzed. The analysis reveals that: with post-grouting, the interface between pile and surrounding soil are strengthened and the relative sliding displacement in between is reduced; end resistance of pile is enhanced and can be mobilized at earlier stage with smaller sliding displacement. As a result, the performance of bored pile is improved with increased bearing capacity and reduced settlement.

  12. Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors

    Science.gov (United States)

    Schilder, Constanze; Kohlhoff, Harald; Hofmann, Detlef; Basedau, Frank; Habel, Wolfgang R.; Baeßler, Matthias; Niederleithinger, Ernst; Georgi, Steven; Herten, Markus

    2013-05-01

    Static and dynamic pile tests are carried out to determine the load bearing capacity and the quality of reinforced concrete piles. As part of a round robin test to evaluate dynamic load tests, structure integrated fibre optic strain sensors were used to receive more detailed information about the strains along the pile length compared to conventional measurements at the pile head. This paper shows the instrumentation of the pile with extrinsic Fabry-Perot interferometers sensors and fibre Bragg gratings sensors together with the results of the conducted static load test as well as the dynamic load tests and pile integrity tests.

  13. Load Test in Sheet Pile

    OpenAIRE

    Luis Orlando Ibanez

    2016-01-01

    In this work, are discussed experiences in the use of mathematical modeling and testing in hydraulic engineering structures. For this purpose the results of load tests in sheet pile, evaluating horizontal and vertical deformations that occur in the same exposed. Comparisons between theoretical methods for calculating deformations and mathematical models based on the Finite Element Method are established. Finally, the coincidence between the numerical model and the results of the load test ful...

  14. Une « révolution » chez les responsables des politiques et les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    19 déc. 2012 ... Leer el artículo en español. Lire Six facteurs favorisant la croissance économique des milieux ruraux pauvres d'Amérique latine. Lire le rapport du Rimisp sur les inégalités en Amérique latine et de nombreux autres documents sur le programme Dynamique de l'occupation du territoire en milieu rural.

  15. 200 Facteurs de contrôle de la diversité des plantations d ...

    African Journals Online (AJOL)

    AZIZ

    Ainsi, cette étude présente les facteurs de contrôle de la diversité des plantations d'alignement de la ville de Porto-Novo au Bénin. ..... Mémoire de DESS en Gestion de l'Environnement, Université de Parakou, ... [10] - A. ALLIO et M. SCHUT, “ Porto-Novo : Une stratégie d'aménagement pour le centre-ville: Dynamique.

  16. Étude Des Potentialités Et Contraintes De Mise En Valeur Durable ...

    African Journals Online (AJOL)

    Le fonctionnement hydrologique du fleuve Mono avec les influences du barrage hydro-électrique de Nangbéto a des impacts directs sur la dynamique de la nappe et de la lame d'eau écoulée qui est aussi liée aux variations spatiales et temporelles du régime pluviométrique. L'analyse physico-chimique du sol montre qu'il ...

  17. Une chercheure spécialiste des questions sexospécifiques en quête ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    13 juil. 2011 ... Je m'intéresse aux répercussions viscérales de la juxtaposition de la pauvreté et de la richesse, juxtaposition qui, dans bien des situations en Afrique du Sud, est très intime. Juxtaposition qui est également amplifiée, fantastiquement orchestrée et même célébrée par la dynamique culturelle, économique et ...

  18. 30 CFR 817.83 - Coal mine waste: Refuse piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Coal mine waste: Refuse piles. 817.83 Section... ACTIVITIES § 817.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 817.81, the... drainage may not be diverted over the outslope of the refuse pile. Runoff from areas above the refuse pile...

  19. Test Setup for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test setup for testing axially static and cyclic loaded piles in sand is described in the following. The purpose for the tests is to examine the tensile capacity of axially loaded piles in dense fully saturated sand. The pile dimensions are chosen to resemble full scale dimension of piles used...... in offshore pile foundations today....

  20. La dynamique spatio-économique contemporaine ou recentrage spatial du développement au Québec

    Directory of Open Access Journals (Sweden)

    Marc-Urbain Proulx

    2002-01-01

    Full Text Available Au Québec, les pôles primaires, secondaires et tertiaires identifiés en 1966 ont servi de base pour établir un modèle descriptif et normatif de l’organisation spatiale. La hiérarchie de centres urbains alors établie devait en principe supporter le drainage, la transformation et la diffusion des facteurs du développement. Trente ans après cette interprétation qui a soutenu l’initiation de politiques publiques dans le cadre d’une stratégie de polarisation en des lieux ciblés, on constate que le développement socio-économique n’est pas tout à fait conforme au modèle initial. L’agglomération de Montréal n’est pas à la hauteur de son rôle moteur. La plupart des centres intermédiaires stagnent. Par contre, certains lieux et certains territoires s’affirment fortement. De nouveaux pôles émergent. Et des corridors de développement se dessinent hors de l’axe traditionnel du Saint-Laurent. Finalement, le Québec assiste à un phénomène de recentrage spatial de son développement socio-économique. Ce qui nous amène à préciser que la dynamique spatiale québécoise nécessite une nouvelle modélisation pour laquelle ce texte offre une modeste contribution.In Quebec, a hierarchy of development poles identified formally in 1966 has been the base for establishing a descriptive and prescriptive model of spatial organization. With Montreal as the main pole, those urban centers may drain, transform and diffuse development factors. After thirty years of public policies based on development pole strategy pointing on specific urban centers, socio-economic development doesn’t really conform the initial model. The great Montreal doesn’t perform as it should. Many intermediate centers are stagnants. But some centers and areas are strongly emerging. And development corridors are appearing outside the traditional Saint-Lawrence line. Finaly Quebec illustrates a phenonenon of spatial recentering of its socio

  1. Static pile load tests on driven piles in Intermediate-Geo Materials : research brief.

    Science.gov (United States)

    2017-02-01

    Research Objectives: : Investigate the use of modified standard penetration tests (MSPT) : Compare field results with predictions made by the WisDOT driving formula, PDA and CAPWAP : Improve prediction of pile lengths and pile capacities ...

  2. Can rupture detector for water cooled piles; Detecteur de rupture de gaine pour piles refroidies a l'eau

    Energy Technology Data Exchange (ETDEWEB)

    Choudens, H de; Guitton, P

    1962-07-01

    The object of this study was to develop a simple, easy to-build, apparatus for showing the appearance of a defect on a fuel element can of a swimming pool reactor. The apparatus used consists of a coil of activated carbon around a NaI(Tl) crystal. Through this coil pass the gases obtained by degassing a sample of water from the reactor; the fission gases which appear when a can leaks are trapped in the carbon; the NaI(Tl) crystal is coupled with a photomultiplier followed by a single-channel selector fixed on a photo-electric peak characteristic of the {gamma} spectrum of fission gases. Preliminary experiments were carried out in laboratory; a more complete device was then built and is now working in the reactor Melusine. (author) [French] Le but de cette etude a ete la realisation d'un appareil simple et facile a realiser destine a indiquer l'apparition d'un defaut sur une gaine des elements combustibles d'une pile piscine. A cet effet, l'appareillage utilise est compose d'un serpentin de charbon active entourant un cristal de NaI (Tl). Ce serpentin est parcouru par les gaz provenant du degazage d'un prelevement d'eau de la piscine du reacteur; les gaz de fission apparaissant lors d'une rupture de gaine sont retenus dans le charbon; le cristal INa (Tl) est couple avec un PM suivi d'un selecteur monocanal cale sur un pic photoelectrique caracteristique du spectre {gamma} des gaz de fission. Des manipulations preliminaires ont ete faites en laboratoire, un dispositif plus complet a ete ensuite monte et fonctionne a la Pile Melusine. (auteurs)

  3. Simulation of bearing capacity of bored piles

    Directory of Open Access Journals (Sweden)

    Majeed Ahmed

    2018-01-01

    Full Text Available This study focuses on how one can possibly predict the ultimate load for the piles that did not reach failure. This challenge was acquired through Chin- Konder method by which, the estimated settlement that correspond to failure load is well defined. Hence, this research aims to make a comparative study between the results of pile load tests carried out in Al-Basrah sewage treatment plant project, and those results induced from the numerical analysis in term of ultimate pile capacity. Consequently, it may give a clear idea on the ability of numerical simulation in getting close to the actual behavior of piles. In the current study, a numerical study using Plaxis 3D Foundation program has been performed on bored piles by the assistance of site investigations of soil. Mohr- Coulomb and linear elastic models were adopted in the simulation for soil and pile respectively. Ten bored piles were used in this analysis under different values of loading. The diameter and length of pile are 0.6m and 24m respectively. The test results indicate that, an excellent agreement has been found as a response of pile capacity between the field and numerical studies. Also, ideal load- settlement curves were created using Chin- Konder method to predict the failure load of bored piles. Also, the results have demonstrated that, the pile capacity obtained from the simulation process is larger about 51% than that design load estimated before the design of piles. This may present a priority to use the finite element method to be accounted as an effective approach in the primary analysis.

  4. Global and local scour at pile groups

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen

    2005-01-01

    This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: (1) Rigid-bed tests, and (2) Actual scour tests. In the former tests, the mean and turbulence properties...... of the flow were measured across the pile groups. The pile group configurations were such that the global scour was distinguished from the local scour. The results show that the global scour can be quite substantial....

  5. Pile Model Tests Using Strain Gauge Technology

    Science.gov (United States)

    Krasiński, Adam; Kusio, Tomasz

    2015-09-01

    Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model. To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements: - a linear and stable relationship between measured and physical values, - the force measurement accuracy of about 0.1 kN, - the range of measured forces up to 30 kN, - resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture, - insensitivity to pile bending, - economical factor. These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.

  6. Global and local scour at pile groups

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen

    2005-01-01

    This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: rigid-bed tests and actual scour tests. In these, the mean and turbulence properties of the flow were measured...... across the pile groups. The pile-group configurations were such that the global scour was distinguished from the local scour. The results show that the global scour can be quite substantial....

  7. Les déterminants de la dynamique spatiale de la ville de Bingerville (sud de la Côte d'Ivoire de 1960 à nos jours

    Directory of Open Access Journals (Sweden)

    Akou Don Franck Valéry Loba

    2010-09-01

    Full Text Available Le présent article rend compte des déterminants de la dynamique spatiale de Bingerville, une ville historique du sud de la Côte d’Ivoire. Les sources cartographiques émanant de missions aériennes ont permis de faire la synthèse de la dynamique spatiale. Une enquête auprès du service technique de la mairie a fourni les informations relatives à la gestion du foncier.L’étude révèle que de 1960, date de proclamation de l’indépendance, jusqu’en 1985, en dépit des interventions de l’Etat-providence, la croissance de la tache urbaine a été très peu significative. A la volonté de l’Etat de bâtir une ville moderne se sont opposées la méfiance et l’hostilité des autochtones, redoutant d’éventuelles expropriations.Avec les changements institutionnels survenus après 1985, qui ont vu l’apparition de nouveaux pouvoirs locaux décentralisés, la ville va connaître un regain de croissance. La communalisation, en mettant à l’ordre du jour l’implication des populations autochtones dans les mécanismes de création du sol urbain, est parvenue à relancer la dynamique des lotissements. Ainsi, sous l’impulsion d’opérateurs immobiliers privés, la ville a vu s’ajouter à son noyau initial de nouveaux quartiers ; elle connaît depuis lors un étirement en direction de ses périphéries ouest et nord et devient partie intégrante du front d’urbanisation oriental de la ville d’Abidjan.This article reports on the spatial dynamics of Bingerville, a historic city in southern Côte d'Ivoire. The study aims to examine data on the nature of the determinants of this dynamic space. The cartographic sources from aerial missions were allowed to synthesize spatial dynamics. A survey of the technical department of the council has provided information on land management.In 1960, the date of declaration of independence until 1985, despite the interventions of the welfare state, the growth of the urban stain was very

  8. Dimensions éthiques de la dynamique des modèles de consommation alimentaires*

    Directory of Open Access Journals (Sweden)

    Duboc Soraya

    2012-09-01

    Full Text Available Consumption patterns are part of a globalized context of interdependence with major uncertainties and increasing constraints. Linking them with food security is essential. Challenges are therefore political, economic, environmental, social but also ethical. Ethics is, mainly, a reflexive intellectual attitude based on problematisation and questioning. One must questions one’s own actions and relationships with others, both in intention and impact. With regard to consumption patterns and food security, the areas in which ‘‘concern [should be] necessary and endless’’ are numerous. Nine major ethical issues can be stated; they are related to agricultural production, consumption, traceability and research priorities.

  9. 11. La dynamique multiculturelle des jeunes : le cas de la ville de ...

    African Journals Online (AJOL)

    The multicultural relationships among the youth in the togolese capital city, the town of Lome evolve, at the threshold of the XXIst century, in a context of metamorphoses resulting from escalating migrations, the cohabitation of different identities and the casting of new ideas which make the current cultural boundaries supple.

  10. Interactive Visualization of Network Dynamics (Visualisation interactive de la dynamique des reseaux)

    Science.gov (United States)

    2014-06-01

    colour coding. The group factor f determines the structure of the hypernode and must be set with careful consideration in respect to the...reference. In experimental psychology it is a well accepted procedure to divide the frames of references into two categories: An egocentric reference...there is almost no colour contrast. For this reason the curvature and feature edges of a surface are harder to recognize and a matching between the

  11. Multiphase flow dynamics and control; Dynamique et controle des ecoulements polyphasiques

    Energy Technology Data Exchange (ETDEWEB)

    Duret, E.

    2005-02-01

    Production in the petroleum industry requires a better knowledge of multiphase flow, as the design of pipelines may cause the flow to become strongly unstable. For instance, for low flow rates and when a sea line ends at a riser, the riser base may accumulate liquid and stop the flow of gas. Then, the upstream gas is compressed until its pressure is large enough to push the liquid slug downstream. Under such conditions, a cyclic process occurs which is called severe slugging, generating large and fast fluctuations in pressure and flow rates. This thesis is devoted to two methods to stabilize this undesirable phenomenon. Using the pipeline's ability to separate phases to pick-up the gas upstream the riser base, they are mainly based on the perturbation theory (fast proportional effect, slow integral effect). The first one uses a secondary riser to transport the gas to the surface facilities. A stability study worked out with the phase diagrams technique shows that it is a good method to control this phenomenon. However, it imposes a high pressure in all the system. Thus, the second controller re-injects the gas at a determined height in the riser to decrease the hydrostatic pressure. A first stability study in open loop give a criterion on the minimal reinjection height. Then, the controller is developed by using the two-time scale control techniques. Finally, let us denote that these two controllers have been validated with a small size experimental set up. (author)

  12. Structures et dynamiques spatiales des villes portuaires: du local au mondial

    Directory of Open Access Journals (Sweden)

    César Ducruet

    2005-04-01

    Full Text Available More than other cities, port cities must constantly adapt to a rapidly changing international trade environment. This adaptation is spurred by their ties to both maritime and land networks and by specific spatio-functional relations between cities and ports, from the local to the global level. For comparative purposes, this paper proposes a new way to interpret the basic structures and trends underlying these complex, and sometimes contradictory, ties.

  13. Impacts des vers de terre sur les composants et la dynamique du sol

    OpenAIRE

    Lemtiri, Aboulkacem; Colinet, Gilles; Alabi, Taofic; Cluzeau, Daniel; Zirbes, Lara; Haubruge, Eric; Francis, Frédéric

    2014-01-01

    Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil fertility by participating to important processes in soil such as soil structure regulation and organic matter dynamics. Earthworms also modify the microbial communities through digestion, stimulation and dispersion in casts. Consequently, changes in the activities of earthworm communities, as a re...

  14. Ajustement automatique des parametres de coupe pour l'obtention de stabilite dynamique en usinage

    Science.gov (United States)

    Tabet, Ricardo

    High speed machining has as principal limitation the dynamic stability of the cutting action which can generate premature wear of the machine spindle and the cutting tool, tool breakage and dimensional errors on the machined part. This phenomenon is known in the literature as chatter and is defined as being self-excited vibrations. This master thesis presents an approach applicable to manufacturing environments that allows eliminating chatter in real time during machining of aerospace aluminum alloys before the damaging effect can occur. A control algorithm is developed in order to detect chatter using a microphone and by analyzing the audio signal in the frequency domain. The analysis allows determining precisely the frequency at which the chatter occurs and therefore, the spindle speed is adjusted in order to make the tooth passing frequency equal to the detected chatter frequency. Also, a new feedrate is determined by keeping a constant chip load and within the physical limits of the cutting tool. The new cutting parameters are then sent out to the machine controller as a command using a communication interface between an external computer and the controller. Multiples experimental tests were conducted to validate the effectiveness to detect and suppress chatter. High speed machining tests, between 15 000 and 33 000 RPM, were performed in order to reflect real conditions for aerospace components manufacturing.

  15. Cue Integration in Dynamic Decision Marking (Integration des indices dans la Prise de Decision Dynamique)

    Science.gov (United States)

    2010-07-01

    e.g., pulling the goalie in hockey). Outcomes are thought of as changes from a reference point- the reference point is itself changed by how the...challenges and training related issues can be pulled from the literature. These are discussed below. General Themes Cue integration involves the use...from our understanding of the term "pattern recognition", a number of general themes, challenges and training related issues can be pulled from the

  16. Comportement et fragmentation dynamique des matériaux quasi-fragiles

    OpenAIRE

    Rouabhi , Ahmed

    2004-01-01

    This thesis seeks to find a computational methodology to simulate both the behaviour and the fragmentation of quasi-brittle materials, such as rocks and concrete, under dynamic loading. Such a methodology will help to a better understanding of the explosive rock breakage mechanisms and, as consequence, will contribute in the optimization of blasting performances. In this study, we consider that the fragmentation process is a natural extension of the fracture process. In order to describe the ...

  17. Resetting dynamic behaviour of pipework systems; Recalage du comportement dynamique des reseaux de tuyauteries

    Energy Technology Data Exchange (ETDEWEB)

    Gaudin, M [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1998-12-31

    Resetting models is applied to electricity generating plant pipework systems. A frequency approach to the problem is made in an original way thanks to the use of precise dynamic rigidity matrices. The method assumes two kinds of unknown: the usually processed mechanical characteristics (Young`s Modulus, density etc.) and new resetting parameters acting on the dynamic behaviour of unknown connections. As the latter have a very wide range of possible variation, they benefit from a change of variable which allows the assumptions formulated to be complied with. The minimized cost function is based on a error in load. The frequencies required for building it are automatically selected thanks to different tests on measurements. Minimization uses a sensitivity technique linked with a method of least standard squares. The method has been programmed in Fortran 90 within the CIRCUS code and tried out on various examples which were simulated and sound effects cases as well as an actual case. (author). 128 refs.

  18. Fusion multi-capteurs pour la représentation et le suivi des objets dynamiques

    OpenAIRE

    Kmiotek , Pawel

    2009-01-01

    The subject of the thesis lies within the scope of the project "Intelligent Vehicle and its integration in the city of the future", led by the Systems and Transportation laboratory of the University of Technology of Belfort-Montbéliard. The objective of this project is to ensure a vehicle autonomous navigation in an urban environment. The autonomous navigation of a vehicle consists of a data processing sequence made up by three stages. The first one relates to the perception of the vehicle en...

  19. Dynamique du peuplement des Oiseaux d'une riziculture et ses ...

    African Journals Online (AJOL)

    Au total, 218 espèces appartenant à 51 familles et 17 ordres ont été identifiées. La présente étude révèle 49 espèces nouvellement observées dans la zone humide de Grand-Bassam. Le peuplement d'Oiseaux rencontré renferme un grand nombre d'individus dont le pic annuel est atteint en juillet. Ce peuplement est ...

  20. Dynamique de la côte apres la realisation des epis, ouvrages de ...

    African Journals Online (AJOL)

    The results showed that an average of 8.50 m/year before the completion of the headlands, the advancing sea has been a brake after implantation, causing significant accretion. This feeder is not always observed linearly each year. Downstream of the headland 7, the evaluation of the erosion rate of the coast line shows ...

  1. Resetting dynamic behaviour of pipework systems; Recalage du comportement dynamique des reseaux de tuyauteries

    Energy Technology Data Exchange (ETDEWEB)

    Gaudin, M. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1997-12-31

    Resetting models is applied to electricity generating plant pipework systems. A frequency approach to the problem is made in an original way thanks to the use of precise dynamic rigidity matrices. The method assumes two kinds of unknown: the usually processed mechanical characteristics (Young`s Modulus, density etc.) and new resetting parameters acting on the dynamic behaviour of unknown connections. As the latter have a very wide range of possible variation, they benefit from a change of variable which allows the assumptions formulated to be complied with. The minimized cost function is based on a error in load. The frequencies required for building it are automatically selected thanks to different tests on measurements. Minimization uses a sensitivity technique linked with a method of least standard squares. The method has been programmed in Fortran 90 within the CIRCUS code and tried out on various examples which were simulated and sound effects cases as well as an actual case. (author). 128 refs.

  2. Les dynamiques transfrontalières en Afrique de l'Ouest: Analyse des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2007-05-31

    May 31, 2007 ... ... are barely noticeable in behaviours and practices at the local level. ... What if it was not merely a matter of treaties, conventions, and regulations? Indeed ... teams of the international organization known as Environnement et ...

  3. The Windscale piles initial decommissioning programme

    International Nuclear Information System (INIS)

    Boorman, T.; Woodacre, A.

    1992-01-01

    The two Windscale Piles, the first large scale nuclear reactors built in the UK were constructed in the late 1940's and operated until the accident in Pile No 1 caused their permanent shutdown in 1957. Following a period of care and maintenance, a programme of initial decommissioning has begun aimed at establishing a satisfactory long-term safe condition for the Windscale Piles Complex with minimum maintenance commitments. For the chimneys this involves the removal of the top filter sections. The pond will be emptied and cleaned. For the Piles the initial phase includes the consideration of options for long-term decommissioning solutions. (author)

  4. Underwater Sound Propagation from Marine Pile Driving.

    Science.gov (United States)

    Reyff, James A

    2016-01-01

    Pile driving occurs in a variety of nearshore environments that typically have very shallow-water depths. The propagation of pile-driving sound in water is complex, where sound is directly radiated from the pile as well as through the ground substrate. Piles driven in the ground near water bodies can produce considerable underwater sound energy. This paper presents examples of sound propagation through shallow-water environments. Some of these examples illustrate the substantial variation in sound amplitude over time that can be critical to understand when computing an acoustic-based safety zone for aquatic species.

  5. Safety precautions in atomic pile control (1962)

    International Nuclear Information System (INIS)

    Furet, J.

    1962-01-01

    We have been led to study the problem of safety in atomic pile control as a result of our participation on the one hand in the planning of C.E.A. atomic piles, and on the other hand in the pile safety sub omission considering atomic pile safety of operational or planned C.E.A. piles. We have thus had to consider the wishes occurring in piles during their operation and also their behaviour in the dynamic state The present work deals mainly with the importance of intrinsic safety devices, with the influence of reactivity variations on the power fluctuations during accidental operation, and with the development of robust and reliable safety appliances. The starting p accident has been especially studied both for low-flux piles where a compromise is necessary between the response time of the safety appliances and the statistical fluctuations and for high lux piles where xenon poisoning has an effect on the lower limit of the velocity of reactivity liberation. The desirability has been stressed of automation as a safety factor in atomic pile control. The details required for an understanding of the diagrams of the apparatus are given. (author) [fr

  6. Simplified analysis of laterally loaded pile groups

    Directory of Open Access Journals (Sweden)

    F.M. Abdrabbo

    2012-06-01

    Full Text Available The response of laterally loaded pile groups is a complicated soil–structure interaction problem. Although fairly reliable methods are developed to predicate the lateral behavior of single piles, the lateral response of pile groups has attracted less attention due to the required high cost and complication implication. This study presents a simplified method to analyze laterally loaded pile groups. The proposed method implements p-multiplier factors in combination with the horizontal modulus of subgrade reaction. Shadowing effects in closely spaced piles in a group were taken into consideration. It is proven that laterally loaded piles embedded in sand can be analyzed within the working load range assuming a linear relationship between lateral load and lateral displacement. The proposed method estimates the distribution of lateral loads among piles in a pile group and predicts the safe design lateral load of a pile group. The benefit of the proposed method is in its simplicity for the preliminary design stage with a little computational effort.

  7. Uranium absorption study pile; Empilement pour le controle de l'absorption de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V; Sautiez, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF{sub 3} counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10{sup -6} boron per gr. of uranium) or better. (author) [French] Nous decrivons un dispositif permettant de mesurer l'absorption des elements combustibles d'une pile. Ce dispositif est constitue par un empilement de graphite dont la region centrale est formee par un reseau regulier de barres d'uranium. Des sources de RaBe et des compteurs a BF{sub 3} sont places de part et d'autre de cette region. En comparant un chargement d'uranium a un chargement etalon d'environ 560 kg, on peut determiner la difference d'absorption entre ces deux chargements. La sensibilite permettrait de deceler une variation d'absorption de l'ordre du ppm de bore (10{sup -6} g de bore par gramme d'uranium) et peut-etre mieux. (auteur)

  8. Static pile load tests on driven piles into Intermediate-Geo Materials.

    Science.gov (United States)

    2016-09-01

    The Wisconsin Department of Transportation (WisDOT) has concerns with both predicting pile lengths and pile capacities for H-piles driven into Intermediate-Geo Materials (IGM). The goal of the research was to perform 7 static axial load tests at 7 lo...

  9. Use of pile driving analysis for assessment of axial load capacity of piles : [technical summary].

    Science.gov (United States)

    2012-01-01

    The dynamic response of a pile during driving is very : complex, involving the interactions of the hammer, cushion, : pile and soil during application of an impact load. : The first analysis aimed at simulating a hammer blow on : a pile was published...

  10. Temperature measurement in French atomic piles; La mesure des temperatures dans les piles atomiques francaises

    Energy Technology Data Exchange (ETDEWEB)

    Weill, J; Rastoix, G

    1950-10-01

    In the Chatillon reactor the temperature is measured (1) in the interior of one of the vertical A1 cylinders filled with UO{sub 2} (temperature interval 20 to 70 deg. C), and (2) in the center of the tank containing D{sub 2}O (20 to 50 deg. C). The instruments used are silver-constantan thermocouples; the wires are insulated by SiO{sub 2} sheaths, those immersed in D{sub 2}O being placed within Al cases 10 mm diameter. In the Saclay reactor the temperature is taken (1) in the interior of 4 U rods (20 to 300 deg. C), (2) at 2 points of the D{sub 2}O mass (20 to 60 deg. C), (3) at one point in graphite (20 to 100 deg. C), and (4) at 5 points in the catalytic setup (200 deg. C). Copper-constantan couples are used (Ag-constantan is not suitable above 150 deg. C); the wires are enclosed in a sheath of glass fabric. In both reactors the accuracy of the temperature measurements is 0.5 deg. C. (author)

  11. Study of the light emitted in the moderation of a heavy-water pile; Etude de la lumiere emise dans le moderateur d'une pile a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-06-15

    During the running of a reactor which uses water as a neutron moderator, a bluish light is seen to appear inside the liquid. A detailed study of this radiation, undertaken on the Fontenay-aux-Roses pile, has shown that the spectrum is identical with that which characterises the light produced by the Cerenkov effect. The light intensity as a function of the pile power grows exponentially as a function of time when the pile diverges, with a lifetime equal to that of the rise in power. An examination of the various particles present in the pile has led to the conclusion that only electrons with an energy greater than 260 keV con produce the Cerenkov light. The light source thus produced is about 2.10{sup 6} photons/cm{sup 2} of water, when the pile power equals 1 watt. (author) [French] Lors du fonctionnement d'un reacteur utilisant l'eau comme moderateur de neutrons, on constate l'apparition d'une lumiere bleutee au sein du liquide. Une etude approfondie de ce rayonnement, entreprise sur la pile Fontenay-aux-Roses a montre que le spectre est identique a celui caracterisant la lumiere produite par effet Cerenkov. L'intensite lumineuse en fonction de Ia puissance de la pile, lors d'une divergence croit exponentiellement en fonction du temps avec une periode egale a celle de la montee en puissance. L'examen des diverses particules presentes dans la pile a permis de conclure que seuls les electrons ayant une energie superieure a 260 keV peuvent produire la lumiere Cerenkov. La source lumineuse ainsi constituee est d'environ 2.10{sup 6} photons/cm{sup 2} d'eau, lorsque la puissance de la pile est egale a 1 watt. (auteur)

  12. Study of the light emitted in the moderation of a heavy-water pile; Etude de la lumiere emise dans le moderateur d'une pile a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-06-15

    During the running of a reactor which uses water as a neutron moderator, a bluish light is seen to appear inside the liquid. A detailed study of this radiation, undertaken on the Fontenay-aux-Roses pile, has shown that the spectrum is identical with that which characterises the light produced by the Cerenkov effect. The light intensity as a function of the pile power grows exponentially as a function of time when the pile diverges, with a lifetime equal to that of the rise in power. An examination of the various particles present in the pile has led to the conclusion that only electrons with an energy greater than 260 keV con produce the Cerenkov light. The light source thus produced is about 2.10{sup 6} photons/cm{sup 2} of water, when the pile power equals 1 watt. (author) [French] Lors du fonctionnement d'un reacteur utilisant l'eau comme moderateur de neutrons, on constate l'apparition d'une lumiere bleutee au sein du liquide. Une etude approfondie de ce rayonnement, entreprise sur la pile Fontenay-aux-Roses a montre que le spectre est identique a celui caracterisant la lumiere produite par effet Cerenkov. L'intensite lumineuse en fonction de Ia puissance de la pile, lors d'une divergence croit exponentiellement en fonction du temps avec une periode egale a celle de la montee en puissance. L'examen des diverses particules presentes dans la pile a permis de conclure que seuls les electrons ayant une energie superieure a 260 keV peuvent produire la lumiere Cerenkov. La source lumineuse ainsi constituee est d'environ 2.10{sup 6} photons/cm{sup 2} d'eau, lorsque la puissance de la pile est egale a 1 watt. (auteur)

  13. Prediction of pile set-up for Ohio soils.

    Science.gov (United States)

    2011-02-01

    ODOT typically uses small diameter driven pipe piles for bridge foundations. When a pile is driven into the subsurface, it disturbs and displaces the soil. As the soil surrounding the pile recovers from the installation disturbance, a time dependant ...

  14. Design phase identification of high pile rebound soils : final report

    Science.gov (United States)

    2010-12-15

    An engineering problem has occurred when installing displacement piles in certain soils. During driving, piles are rebounding excessively during each hammer blow, causing delay and as a result may not achieve the required design capacities. Piles dri...

  15. Dynamique communautaire autour de la gestion de la sante ...

    African Journals Online (AJOL)

    importance de certains facteurs, en l'occurrence les perceptions culturelles qui rendent pourtant compte de la dimension sociale, culturelle et symbolique de la grossesse. Une telle situation ne peut que compromettre l'atteinte des Objectifs 4 et 5 du ...

  16. Dynamiques sociale et spatio-temporelle resultant de la colonisation ...

    African Journals Online (AJOL)

    Cette étude vise à analyser le phénomène de la colonisation agricole, les changements socio-économiques apparus et les nouvelles formes de gestion des ressources ... Through Models used for better understanding the land use change dynamics, it appeared clearly that agricultural colonization will gain always more in ...

  17. In-pile Instrumentation Development

    International Nuclear Information System (INIS)

    Vermeeren, L.

    2005-01-01

    Advanced irradiations in research reactors require the on-line monitoring of crucial parameters like neutron fluxes, gamma dose rates, central fuel rod temperatures, fission gas release pressures and small geometry changes. Our activities in this field aim at a detailed understanding of the sensor behaviour in the irradiation conditions in order to extract reliable real-time information. The objectives of work performed by SCK-CEN are to study of the on-line in-pile measurement of gamma and neutron fluxes in real time and to investigate parasitic radiation-induced signals in instrumentation cables

  18. First experiments results about the engineering model of Rapsodie; Premiers resultats d'essais interessant le bloc pile de rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Chalot, A; Ginier, R; Sauvage, M [Association Euratom-CEA Cadarache (France). Centre d' Etudes Nucleaires

    1964-07-01

    This report deals with the first series of experiments carried out on the engineering model of Rapsodie and on an associated sodium facility set in a laboratory hall of Cadarache. It conveys more precisely: 1/ - The difficulties encountered during the erection and assembly of the engineering model and a compilation of the results of the first series of experiments and tests carried out on this installation (loading of the subassemblies preheating, thermal chocks...). 2/ - The experiments and tests carried out on the two prototypes control rod drive mechanisms which brought to the choice for the design of the definitive drive mechanism. As a whole, the results proved the validity of the general design principles adopted for Rapsodie. (authors) [French] Ce rapport traite des premiers essais realises sur la maquette du bloc pile de Rapsodie et sur une installation annexe de sodium, implantees dans un hall d'essais de Cadarache. Il fait part: 1/- Des difficultes eprouvees lors du montage de la maquette et rassemble les resultats des premiers essais effectues sur cette installation (chargement des assemblages, prechauffage, chocs thermiques...). 2/- Des essais realises sur deux prototypes de mecanisme de barre de controle qui ont conduit a la conception du mecanisme definitif. L'ensemble des resultats obtenus a permis de confirmer la validite des principes adoptes pour la pile Rapsodie. (auteurs)

  19. [Present conceptions of the C.E.A. concerning] the development of fast neutron reactors in France; [Les conceptions actuelles du C.E.A. concernant] la filiere des reacteurs a neutrons rapides en France

    Energy Technology Data Exchange (ETDEWEB)

    Vendryes, G; Gaussens, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Pasquer, R [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    . (authors) [French] 1 - Situation des reacteurs a neutrons rapides dans le programme d'energie nucleaire francais. En developpant un programme base sur l'uranium naturel, la France se trouvera dotee d'un stock important de plutonium riche on isotopes superieurs. L'existence de ce plutonium et de l'uranium appauvri provenant des memes reacteurs a pour consequence logique leur emploi dans des reacteurs a neutrons rapides. Justifiee par cet interet a court terme, la mise au point de reacteurs a neutrons rapides repond par ailleurs a une necessite pour l'avenir. 2 - Enonce des caracteristiques d'une centrale a neutrons rapides de 1000 MW el. Nous indiquons les caracteristiques d'une future centrale a neutrons rapides chargee au plutonium et refroidie au sodium. Si incertaines qu'elles soient, elles constituent un guide necessaire a l'orientation de nos travaux. 3 - Etudes effectuees a ce jour: Nous donnons un apercu des etudes souvent tres preliminaires qui ont permis de retenir les caracteristiques citees plus haut. Les principaux domaines techniques abordes sont les suivants: - Neutronique (masses critiques, taux de regeneration, enrichissements, aplatissement du flux de neutrons, coefficients de reactivite, evolution de la reactivite en fonction de l'irradiation), - Dynamique, controle et surete, - Combustible, - Technologie (conception du bloc-pile, des circuits de sodium, des dispositifs pour la manutention des assemblages). Ces etudes techniques se completent de considerations economiques. Le choix de caracteristiques optimales est lie a l'existence de programmes de production d'electricite et, dans ces programmes, a celle des reacteurs a neutrons thermiques producteurs de plutonium. On montre comment il y a lieu de tenir compte de l'existence du plutonium dans ce contexte, et quels sont les mecanismes qui rattachent l'economie de ce plutonium au choix des parametres essentiels des reacteurs surgenerateurs. 4 - Reacteur prototype: On justifie l'interet d'une etape

  20. Modélisation en dynamique des populations : Impacts des changements climatiques sur les populations de tiques

    OpenAIRE

    Khouaja , Leila; Ben Miled , Slimane; Hbid , Hassan

    2016-01-01

    International audience; Epidemiology had an important development these last years allowing the resolution of a large number of problems and had good prediction on disease evolution. However, the transmission of several vector-borne diseases is closely connected to environmental protagonists, specially in the parasite-host interaction. Moreover, understanding the disease transmission is related to studying the ecology of all protagonists. These two levels of complexity(epidemiology and ecolog...

  1. Study of the multiplication factor in the core of Saclay; Etude du facteur de multiplication dans la pile de Saclay

    Energy Technology Data Exchange (ETDEWEB)

    Jacrot, B; Netter, F; Raievski, V [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

    1953-07-01

    Several methods were studied for the measure of the multiplication factor strength in a core, by experiences in subcritical regime. These methods are applied to the determination of the effect on the reactivity of such different parameters of the battery that: heavy water level, position of the regulating plates. These results are used to establish an experimental relation between the time of the rise of the divergent core and the factor of effective multiplication. It is also given the application of these methods to the assessment of the power of the core. (author) [French] Des methodes ont ete etudie pour la mesure du facteur de multiplication effectif dans une pile, par des experiences en regime sous-critique. Ces methodes sont appliquees a la determination de l'effet sur la reactivite de differents parametres de la pile tels que: niveau d'eau lourde, position des plaques de reglage. Ces resultats sont utilises pour etablir une relation experimentale entre le temps de la montee de la pile divergente et le facteur de multiplication effectif. On donne egalement l'application de ces methodes a l'evaluation de la puissance de la pile. (auteur)

  2. Some Remarks on Foundation Pile Testing Procedures

    Science.gov (United States)

    Rybak, Jarosław

    2017-10-01

    This work presents the review of pile capacity testing techniques. In an overview, the key points in pile designing are: determination of the appropriate computational schemes, reliable data on loads and the properties of structural materials (in particular, of the soil mass, which is marked by the greatest variability). The procedure of constructing a pile foundation should include: carrying out soil tests in the scope that ensures safe designing, selecting a piling technology that is relevant both to geotechnical conditions and expected loads, drafting a piling design together with the design of load tests, setting up a testing station for further load tests, static and/or dynamic tests of pile load capacity, preceded by supplementary soil tests when the conditions of test pile installation fail to comply with the design assumptions or when the pile length exceeds the depth of the previously investigated soil, making documentation of load capacity tests (with an additional correction of the piling design), the actual piling (ongoing analysis of pile driving logs and, if necessary, testing the piles’ integrity), drawing up the as-built documentation. Unfortunately, the design is corrected after the load test have been conducted only if the piles fail to show the designed bearing capacity. The designer is then obliged to revise the design assumptions on the basis of tests results. If the test results account for the a greater bearing capacity than necessary and it would be recommendable to limit the extent of the planned (i.e. set out in the contract) piling works, usually neither the contractor nor the designer, nor even the Construction Site Supervisor, acting for the benefit of the Investor, are willing to take on the responsibility for reducing the scope of the piling works. The necessity of conducting additional control tests before and during the implementation of the construction project is often treated by the investors as an attempt at extorting extra

  3. Structures et dynamiques de l'espace gabonais

    Directory of Open Access Journals (Sweden)

    Stéphane LEROY

    1995-06-01

    Full Text Available L’organisation spatiale du Gabon peut être envisagée comme le résultat de l’arrangement particulier de structures spatiales générales, communes à la grande majorité des pays côtiers de l’Afrique occidentale et équatoriale. La modélisation graphique permet de le vérifier.

  4. Chroniques d'habitat et dynamique de populations de truite

    Directory of Open Access Journals (Sweden)

    CAPRA H.

    1995-04-01

    Full Text Available Une nouvelle méthode a permis de quantifier des Durées Continues d'Habitat Limitant (méthode DCHL à partir de chroniques d'habitat potentiel, pour la truite fario (Salmo trutta fario, L.. Cette méthode a été appliquée sur deux cours d'eau naturels et sur une station soumise à éclusée. Elle a été validée sur les deux cours d'eau naturels en ce qui concerne l'habitat limitant pour les jeunes truites de l'année (0+. Elle offre un outil pratique d'analyse des périodes d'habitat limitant en régime naturel. En situation d'éclusées, l'interprétation des résultats est différente et nécessite encore un effort important de suivi biologique.

  5. Evolution du génome des Streptomyces : transfert horizontal et variabilité des extrémités chromosomiques

    OpenAIRE

    Choulet, Frédéric

    2006-01-01

    L'analyse et la comparaison des génomes permettent d'appréhender les forces évolutives à la base de leur dynamique et les contraintes qui s'opposent à la variabilité. Chez les bactéries, le transfert horizontal joue un rôle majeur dans leur diversification. Ce travail traite de l'évolution du génome des Streptomyces qui sont des bactéries du sol responsables de la biosynthèse d'une très grande diversité de composés actifs. Leur intérêt applicatif est considérable et touche des domaines variés...

  6. Contexte de l'accès au matériel didactique dans les universités des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les étudiants ont de plus en plus accès à tout ce dont ils ont besoin, dans une ... de textes électroniques soumis à aucun contrôle et auquel l'on a accès sans ... et de la dynamique des politiques, de même qu'au mouvement émergent en ce qui ... IWRA/CRDI sur les changements climatiques et la gestion adaptive de l'eau.

  7. Archive of Geosample Information from the Universite de Savoie Laboratoire Environnements, Dynamiques et Territoires de la Montagne (EDYTEM) Core Repository

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Universite de Savoie Laboratoire Environnements, Dynamiques et Territoires de la Montagne (EDYTEM) is in the process of coding information about their marine and...

  8. Analysis of effect of different construction methods of piles on the end effect on skin friction of piles

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hongbo; CHEN Zhuchang

    2007-01-01

    Based on the comparative analysis of end effect on skin friction of displacement-pile (driven pile),the end effect on skin friction of bored pile is studied.The end effect on skin friction between driven pile and bored pile is different and the end effect on skin friction of bored pile is reduce of skin friction in the soil layer adjacent to the pile end.The degradation degree of skin friction is deduced with the increase of the distance from pile end.The concept of additional mud cake formed by the effect of cushion at the bottom of borehole during pouring concrete is introduced to explain the mechanism of end effect on skin friction of the bored pile.The test results of post-grouting piles indicate that the post-grouting technique is an effective way to improve the end effect on skin friction of bored pile.

  9. Reliability of Estimation Pile Load Capacity Methods

    Directory of Open Access Journals (Sweden)

    Yudhi Lastiasih

    2014-04-01

    Full Text Available None of numerous previous methods for predicting pile capacity is known how accurate any of them are when compared with the actual ultimate capacity of piles tested to failure. The author’s of the present paper have conducted such an analysis, based on 130 data sets of field loading tests. Out of these 130 data sets, only 44 could be analysed, of which 15 were conducted until the piles actually reached failure. The pile prediction methods used were: Brinch Hansen’s method (1963, Chin’s method (1970, Decourt’s Extrapolation Method (1999, Mazurkiewicz’s method (1972, Van der Veen’s method (1953, and the Quadratic Hyperbolic Method proposed by Lastiasih et al. (2012. It was obtained that all the above methods were sufficiently reliable when applied to data from pile loading tests that loaded to reach failure. However, when applied to data from pile loading tests that loaded without reaching failure, the methods that yielded lower values for correction factor N are more recommended. Finally, the empirical method of Reese and O’Neill (1988 was found to be reliable enough to be used to estimate the Qult of a pile foundation based on soil data only.

  10. Radioprotection problems resulting from the presence of experimental devices around an atomic reactor; Problemes de radioprotection poses par l'implantation de dispositifs experimentaux aupres d'une pile atomique

    Energy Technology Data Exchange (ETDEWEB)

    Fitoussi, L; Lebouleux, Ph; Bricard, Ph; Moreau, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The setting up of experimental devices around a reactor produces dangers of irradiation and radioactive contamination which can become very great in the case of an accident, especially if the in-pile portion contains fissile matter. This may result in irradiation of personnel, prohibition of access to the experimental zones until the sources of irradiation and contamination have been eliminated, and a prolonged stoppage of the reactor. The plans for an in-pile experiment should take into account radioprotection factors; the aim of these is to reduce to a minimum the radioactive risks normally encountered during the experiment and to eliminate any risks of bad accidents and their consequences. In this report are classified the various types of experiments requiring installations outside the pile itself; for each of these experiments the particular radioprotection factors are given. In order to make possible a study of the radioactive dangers likely to arise during a projected experiment, the authors summarize the physical and technical data required by radioprotection specialists and give the rules and general advice concerning radioprotection which should be useful during the planning of an in-pile experiment and the setting-up of the equipment. (authors) [French] L'implantation de dispositifs experimentaux aupres des reacteurs cree des risques d'irradiation et de contamination radioactive qui peuvent devenir importants en cas d'accident, surtout si la partie en pile comprend des matieres fissiles. Il peut en resulter des irradiations de personne, l'interdiction des aires experimentales jusqu'a elimination des sources d'irradiation et de contamination, un arret prolonge de la pile. L'etude d'un projet d'experience en pile doit donc tenir compte des considerations de radioprotection dont le souci est de reduire aux niveaux tolerables les risques radioactifs inherents au fonctionnement normal de l'experience et d'eliminer les risques d'accidents graves et leurs

  11. 30 CFR 77.214 - Refuse piles; general.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; general. 77.214 Section 77.214... Installations § 77.214 Refuse piles; general. (a) Refuse piles constructed on or after July 1, 1971, shall be..., tipples, or other surface installations and such piles shall not be located over abandoned openings or...

  12. 30 CFR 816.83 - Coal mine waste: Refuse piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Coal mine waste: Refuse piles. 816.83 Section... ACTIVITIES § 816.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 816.81, the... drainage may not be diverted over the outslope of the refuse piles. Runoff from the areas above the refuse...

  13. 30 CFR 77.215-4 - Refuse piles; abandonment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; abandonment. 77.215-4 Section 77... MINES Surface Installations § 77.215-4 Refuse piles; abandonment. When a refuse pile is to be abandoned... refuse pile shall be abandoned in accordance with a plan submitted by the operator and approved by the...

  14. Measurements of pile driving noise from control piles and noise-reduced piles at the Vashon Island ferry dock.

    Science.gov (United States)

    2017-04-01

    As part of the Washington State Department of Transportation (WSDOT) pile attenuation test program, : researchers from the University of Washington Applied Physics Laboratory (APL-UW) conducted underwater sound : measurements on 7 and 8 December 2015...

  15. EL3 reactor description and safety analysis report; Pile EL3, rapport descriptif et de surete

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1969-02-01

    ). Elle est concue pour fonctionner a une puissance thermique maximale de 20 mW. Elle fournit un flux maximal thermique de 10{sup 14} neutrons/cm{sup 2}/sec. Elle dispose de nombreux dispositifs experimentaux. La pile EL-3 est contenue, avec ses auxiliaires des circuits des fluides, dans une enceinte etanche, en legere depression. Le circuit d'eau lourde de refroidissement primaire est entierement contenu dans cette enceinte. Son refroidissement est assure, par l'intermediaire d'un circuit secondaire en eau legere, par des refrigerants atmospheriques. Les circuits de ventilation de l'enceinte etanche et du bloc pile ne rejettent l'air a l'exterieur, en fonctionnement normal, par une cheminee particulierement etudiee, qu'apres filtrage et eventuellement dilution. La contamination eventuelle de l'eau legere, ou de l 'air, par des produits actifs, est controlee en permanence, pour permettre l'arret du reacteur et eviter le rejet a l'atmosphere de produits dangereux. La pile El3, mise en chantier en mai 1955, a diverge en juillet 1957, effectue sa premiere montee en puissance en decembre 1957 et a atteint sa pleine puissance en avril 1958. La mise en place du combustible actuel (cristal de Neige) s'est effectue durant l'ete 1964. Pile a vocation experimentale, elle est utilisee pour des etudes theoriques et technologiques par irradiation de materiel dans les canaux experimentaux et dans les cellules memes du coeur, avec possibilites de constituer des boucles independantes (en ce qui concerne les fluides de refroidissement). Trente canaux verticaux sont reserves a la fabrication de radioelements artificiels. (auteur)

  16. EL3 reactor description and safety analysis report; Pile EL3, rapport descriptif et de surete

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1969-02-01

    concue pour fonctionner a une puissance thermique maximale de 20 mW. Elle fournit un flux maximal thermique de 10{sup 14} neutrons/cm{sup 2}/sec. Elle dispose de nombreux dispositifs experimentaux. La pile EL-3 est contenue, avec ses auxiliaires des circuits des fluides, dans une enceinte etanche, en legere depression. Le circuit d'eau lourde de refroidissement primaire est entierement contenu dans cette enceinte. Son refroidissement est assure, par l'intermediaire d'un circuit secondaire en eau legere, par des refrigerants atmospheriques. Les circuits de ventilation de l'enceinte etanche et du bloc pile ne rejettent l'air a l'exterieur, en fonctionnement normal, par une cheminee particulierement etudiee, qu'apres filtrage et eventuellement dilution. La contamination eventuelle de l'eau legere, ou de l 'air, par des produits actifs, est controlee en permanence, pour permettre l'arret du reacteur et eviter le rejet a l'atmosphere de produits dangereux. La pile El3, mise en chantier en mai 1955, a diverge en juillet 1957, effectue sa premiere montee en puissance en decembre 1957 et a atteint sa pleine puissance en avril 1958. La mise en place du combustible actuel (cristal de Neige) s'est effectue durant l'ete 1964. Pile a vocation experimentale, elle est utilisee pour des etudes theoriques et technologiques par irradiation de materiel dans les canaux experimentaux et dans les cellules memes du coeur, avec possibilites de constituer des boucles independantes (en ce qui concerne les fluides de refroidissement). Trente canaux verticaux sont reserves a la fabrication de radioelements artificiels. (auteur)

  17. Soil heating during burning of forest slash piles and wood piles

    Science.gov (United States)

    Matt D. Busse; Carol J. Shestak; Ken R. Hubbert

    2013-01-01

    Pile burning of conifer slash is a common fuel reduction practice in forests of the western United States that has a direct, yet poorly quantified effect on soil heating. To address this knowledge gap, we measured the heat pulse beneath hand-built piles ranging widely in fuel composition and pile size in sandy-textured soils of the Lake Tahoe Basin. The soil heat pulse...

  18. L’espace social des étudiants marocains dans la mobilité internationale. Spatialisation des réseaux et recomposition territoriale

    Directory of Open Access Journals (Sweden)

    Sabrina Marchandise

    2014-02-01

    Full Text Available La communication centre le propos sur l’étude des migrations étudiantes internationales, particulièrement marocaines. Ce thème se situe dans un contexte d’internationalisation de l’enseignement supérieur, au cœur des enjeux actuels qui ont trait à la mobilité des savoirs et des compétences et plus généralement dans les enjeux sociaux des réseaux. L’objectif général de la recherche réside dans la compréhension de la façon dont les étudiants marocains se représentent, conçoivent et produisent leurs rapports à l’espace, territorialisant de nombreuses aires. Comment alors penser les nouvelles formes de territorialité des étudiants marocains ? Les traductions spatiales des différents facteurs intervenant dans la dynamique sociale étudiante peuvent fournir des clés de lecture et d’interprétation des changements en cours (usages et technologies. Le projet consiste donc à saisir comment est structuré l’espace social des étudiants à travers les différents réseaux. Cet objectif pourra être atteint grâce à la spatialisation des réseaux étudiants marocains. Un croisement des méthodes et une articulation des échelles s’avèrent nécessaires pour une approche par les trajectoires et les pratiques des étudiants.

  19. Introduction of effective piles in a base structure

    Directory of Open Access Journals (Sweden)

    В.Б. Кашка

    2005-03-01

    Full Text Available  Design features of effective piles such as СВ and their advantages in use are considered at the device of the pile bases in comparison with widely widespread types of piles. From results of comparative tests of piles under static pressing loading in different earth conditions the tendency of redistribution of bearing (carrying ability between a trunk and expansions an effective pile such as СВ was determined on earth conditions.

  20. Performance of pile supported sign structures : [brief].

    Science.gov (United States)

    2015-05-01

    Sign structures in Wisconsin are typically supported by drilled shaft foundations or spread : footing foundations. However, when the soil conditions are not suitable to be supported on : drilled shafts or spread footings, a group of piles could suppo...

  1. New trends in pile safety instrumentation

    International Nuclear Information System (INIS)

    Furet, J.

    1961-01-01

    This report addresses the protection of nuclear piles against damages due to operation incidents. The author discusses the current trends in the philosophy of safety of atomic power piles, identifies the parameters which define safety systems, presents tests to be performed on safety chains, comments the relationship between safety and the decrease of the number of pile inadvertent shutdowns, discusses the issues of instrument failures and chain multiplicity, comments the possible improvement of the operation of elements which build up safety chains (design simplification, development of semiconductors, replacement of electromechanical relays by static relays), the role of safety logical computers and the development of automatics in pile safety, presents automatic control as a safety factor (example of automatic start-up), and finally comments the use of fuses

  2. Displacement pile installation effects in sand

    NARCIS (Netherlands)

    Beijer-Lundberg, A.

    2015-01-01

    Installation effects govern the post-installation behaviour of displacement piles in sand. These effects are currently not completely understood. Suitable experimental techniques to model these installation effects include field, laboratory and experimental models. In the current thesis a

  3. Le tassement des appuis du Pont de Normandie

    OpenAIRE

    COMBARIEU, O

    2003-01-01

    Le Pont de Normandie, ouvrage haubané franchissant l'estuaire de la Seine, fait l'objet depuis le début de sa construction d'un suivi géométrique très précis. En particulier, les appuis des deux pylônes principaux, des deux culées et des vingt-six piles des viaducs d'accès sont régulièrement nivelés. Après un descriptif géotechnique du site, la manière dont l'étude des tassements des appuis sur pieux a été abordée, implicitement ou non, est présentée. Pour les pylônes principaux particulièrem...

  4. Tension Tests On Bored Piles In Sand

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

    2006-01-01

    The lengths of the bored piles varied from 2 m to 6 m and all were of a diameter of 140 mm. The piles were tested to failure in tension and the load-displacement relations were recorded. The investigation has shown pronounced differences between the load bearing capacities obtained by different...... design methods. The methods proposed by Fleming et al. and Reese & O’Neill seem to produce the best match with the test results....

  5. Pulse pile-up. I: Short pulses

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1990-07-01

    The search for rare large pulses against an intense background of smaller ones involves consideration of pulse pile-up. Approximate methods are presented, based on ruin theory, by which the probability of such pile-up may be estimated for pulses of arbitrary form and of arbitrary pulse-height distribution. These methods are checked against cases for which exact solutions are available. The present paper is concerned chiefly with short pulses of finite total duration. (Author) (5 refs., 24 figs.)

  6. Grouting of uranium mill tailings piles

    International Nuclear Information System (INIS)

    Boegly, W.J. Jr.; Tamura, T.; Williams, J.D.

    1984-03-01

    A program of remedial action was initiated for a number of inactive uranium mill tailings piles. These piles result from mining and processing of uranium ores to meet the nation's defense and nuclear power needs and represent a potential hazard to health and the environment. Possible remedial actions include the application of covers to reduce radon emissions and airborne transport of the tailings, liners to prevent groundwater contamination by leachates from the piles, physical or chemical stabilization of the tailings, or moving the piles to remote locations. Conventional installation of liners would require excavation of the piles to emplace the liner; however, utilization of grouting techniques, such as those used in civil engineering to stabilize soils, might be a potential method of producing a liner without excavation. Laboratory studies on groutability of uranium mill tailings were conducted using samples from three abandoned piles and employing a number of particulate and chemical grouts. These studies indicate that it is possible to alter the permeability of the tailings from ambient values of 10 -3 cm/s to values approaching 10 -7 cm/s using silicate grouts and to 10 -8 cm/s using acrylamide and acrylate grouts. An evaluation of grouting techniques, equipment required, and costs associated with grouting were also conducted and are presented. 10 references, 1 table

  7. Evolução das relações entre cidades e portos: entre lógicas homogeneizantes e dinâmicas de diferenciação Évolution des relations entre villes et ports: entre logiques homogénéisatrices et dynamiques de différenciation Evolution of relationships between cities and ports: homogenizing trends and differentiation dynamics

    Directory of Open Access Journals (Sweden)

    Flavia Nico Vasconcelos

    2012-06-01

    Full Text Available A fase atual da globalização é acompanhada por mutações que, ao incidirem sobre a malha global das interações espaciais de longa distância, redefinem a paisagem institucional, as modalidades técnico-operacionais e a organização espacial do sistema portuário mundial. A situação dos portos, pelos quais transitam parte substancial do comércio internacional de mercadorias, é paradoxal e complexa. As estratégias desenvolvidas pelos atores que dominam o horizonte marítimo do porto somadas às estratégias impostas pelos atores econômicos que dominam seu horizonte terrestre colocam as cidades portuárias em um caminho marcado por redes de transporte e de produção. O jogo das políticas portuárias, oscilantes entre concorrência e complementaridade, consiste em posicionar o porto no coração dessas redes através da incorporação de um número crescente de variáveis econômicas, comerciais, urbanísticas, ambientais e sociais frente às racionalidades funcionais e territoriais de atores que podem transformar o porto em um simples nó de transbordamento ou, ao contrário, em um grande centro logístico. Com base na definição de portos comerciais como territórios situados nos espaços de manobra de um “tabuleiro” mundial e regional existem possibilidades para articulações diferenciadas entre as competências localizadas no porto comercial, no sistema produtivo e nos recursos do território urbano e para uma análise com trajetória em três escalas: no nível global, através da globalização; no nível meso-econômico, no âmbito dos sistemas regionais que capturam os volumes crescentes de fluxos e atividades de transformação; e, no nível local, sobre o território da cidade portuária. Essa abordagem nos permite elaborar uma tipologia das cidades portuárias como territórios de circulação e/ou territórios produtivos.La phase actuelle de la mondialisation porte en elle des mutations dont l´incidence sur la

  8. Study of the nature and of the properties of paramagnetic centers observed by electron spin resonance in conjugated polymers; Etude de la nature des propriete des centres paramagnetiques observes par resonance paramagnetique electronique dans les polymeres conjugues

    Energy Technology Data Exchange (ETDEWEB)

    Nechtschein, M [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-06-15

    Conjugated polymers contain paramagnetic centers. It is established that these centers are free radicals and a model which defines their electronic structure is proposed. The interactions between these centers are studied, notably by dynamic polarisation experiments. Finally it is shown that the centers have catalytic properties. (author) [French] Les polymeres conjugues contiennent des centres paramagnetiques. L'origine radicalaire de ces centres est etablie et un modele precisant leur structure electronique est propose. Les interactions entre ces centres sont etudiees, notamment a l'aide d'experiences de polarisation dynamique. Des proprietes catalytiques sont mises en evidence. (auteur)

  9. Study of the nature and of the properties of paramagnetic centers observed by electron spin resonance in conjugated polymers; Etude de la nature des propriete des centres paramagnetiques observes par resonance paramagnetique electronique dans les polymeres conjugues

    Energy Technology Data Exchange (ETDEWEB)

    Nechtschein, M. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-06-15

    Conjugated polymers contain paramagnetic centers. It is established that these centers are free radicals and a model which defines their electronic structure is proposed. The interactions between these centers are studied, notably by dynamic polarisation experiments. Finally it is shown that the centers have catalytic properties. (author) [French] Les polymeres conjugues contiennent des centres paramagnetiques. L'origine radicalaire de ces centres est etablie et un modele precisant leur structure electronique est propose. Les interactions entre ces centres sont etudiees, notamment a l'aide d'experiences de polarisation dynamique. Des proprietes catalytiques sont mises en evidence. (auteur)

  10. Thermal conductivity of sintered UO{sub 2} under in-pile conditions; Conductibilite thermique de l'UO{sub 2} fritte dans les conditions d'utilisation en pile

    Energy Technology Data Exchange (ETDEWEB)

    Stora, J P; Bernardy De Sigoyer, B; Delmas, R; Deschamps, P; Lavaud, B; Ringot, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The temperature distribution in a stack of sintered UO{sub 2} cylinders has been studied both in the laboratory where the heat energy is produced by an axial heating element, and in-pile, where the heating is due solely to nuclear effects. Under a high thermal gradient the UO{sub 2} cracks both along radial planes and along pseudo-cylindrical surfaces: these latter act as thermal barriers to the heat flow, It is therefore an apparent thermal conductivity k{sub a}(T), lower than the intrinsic value k(T) of this parameter which is measured. The efficiency of these barriers decreases when the gap decreases and when the external pressure acting on the cracked stack increases: in the limiting case, for high values of the binding strain, k{sub a}(T) {approx_equal} k(T). In the domain of phonon conduction (T {<=} 1350 deg C), the expression kw.cm{sup -1}.C{sup -1}=1/(11+0.024*T) accounts for the real thermal conductivity. Above 1350 deg C the thermal conductivity increases. Two in-pile measurements up to 1250 deg C carried out using cartridges fitted with thermocouples confirm, within the limits of experimental error, the above expression and the qualitative effects of the binding strains. Similar tests have been carried out-of-pile and in-pile on the real shape of the EL-4 fuel 'pencils'. Out-of-pile, the influence of the initial free gap, of the nature of the gas filing the 'pencil' and of the external pressure have been studied; the results are compatible with the above interpretation; It appears that an external pressure of 60 kg/cm{sup 2} is insufficient to restore completely the thermal conductivity of the fuel. (authors) [French] La distribution de temperature dans un empilement de cylindres d'UO{sub 2} fritte est etudiee a la fois au laboratoire, ou l'energie calorifique est produite par un element chauffant axial, et en pile, ou l'echauffement est uniquement nucleaire. Sous gradient thermique eleve, l'UO{sub 2} se fracture a la fois suivant des plans radiaux et

  11. Experimental Verification of Integrity of Low-Pressure Injection Piles Structure - Pile Internal Capacity

    Science.gov (United States)

    Pachla, Henryk

    2017-12-01

    The idea of strengthening the foundation using injection piles lies in transferring loads from the foundation to the piles anchorage in existing structure and formed in the soil. Such a system has to be able to transfer loads from the foundation to the pile and from the pile onto the soil. Pile structure often reinforced with steel element has to also be able to transfer such a loading. According to the rules of continuum mechanics, the bearing capacity of such a system and a deformation of its individual elements can be determined by way of an analysis of the contact problem of three interfaces. Each of these surfaces is determined by different couples of materials. Those surfaces create: pile-foundation anchorage, bonding between reinforcement and material from which the pile is formed and pilesoil interface. What is essential is that on the contact surfaces the deformation of materials which adhere to each other can vary and depends on the mechanical properties and geometry of these surfaces. Engineering practice and experimental research point out that the failure in such structures occurs at interfaces. The paper is concentrating on presenting the experiments on interaction between cement grout and various types of steel reinforcement. The tests were conducted on the special low pressure injection piles widely used to strengthen foundations of already existing structures of historical buildings due to the technology of formation and injection pressure.

  12. Experimental Verification of Integrity of Low-Pressure Injection Piles Structure – Pile Internal Capacity

    Directory of Open Access Journals (Sweden)

    Pachla Henryk

    2017-12-01

    Full Text Available The idea of strengthening the foundation using injection piles lies in transferring loads from the foundation to the piles anchorage in existing structure and formed in the soil. Such a system has to be able to transfer loads from the foundation to the pile and from the pile onto the soil. Pile structure often reinforced with steel element has to also be able to transfer such a loading. According to the rules of continuum mechanics, the bearing capacity of such a system and a deformation of its individual elements can be determined by way of an analysis of the contact problem of three interfaces. Each of these surfaces is determined by different couples of materials. Those surfaces create: pile-foundation anchorage, bonding between reinforcement and material from which the pile is formed and pilesoil interface. What is essential is that on the contact surfaces the deformation of materials which adhere to each other can vary and depends on the mechanical properties and geometry of these surfaces. Engineering practice and experimental research point out that the failure in such structures occurs at interfaces. The paper is concentrating on presenting the experiments on interaction between cement grout and various types of steel reinforcement. The tests were conducted on the special low pressure injection piles widely used to strengthen foundations of already existing structures of historical buildings due to the technology of formation and injection pressure.

  13. Evaluation of axial pile bearing capacity based on pile driving analyzer (PDA) test using Neural Network

    Science.gov (United States)

    Maizir, H.; Suryanita, R.

    2018-01-01

    A few decades, many methods have been developed to predict and evaluate the bearing capacity of driven piles. The problem of the predicting and assessing the bearing capacity of the pile is very complicated and not yet established, different soil testing and evaluation produce a widely different solution. However, the most important thing is to determine methods used to predict and evaluate the bearing capacity of the pile to the required degree of accuracy and consistency value. Accurate prediction and evaluation of axial bearing capacity depend on some variables, such as the type of soil, diameter, and length of pile, etc. The aims of the study of Artificial Neural Networks (ANNs) are utilized to obtain more accurate and consistent axial bearing capacity of a driven pile. ANNs can be described as mapping an input to the target output data. The method using the ANN model developed to predict and evaluate the axial bearing capacity of the pile based on the pile driving analyzer (PDA) test data for more than 200 selected data. The results of the predictions obtained by the ANN model and the PDA test were then compared. This research as the neural network models give a right prediction and evaluation of the axial bearing capacity of piles using neural networks.

  14. The Effects of Time on Soil Behaviour and Pile Capacity

    DEFF Research Database (Denmark)

    Augustesen, Anders

    When designing pile foundations, static design equations, pile driving formulae, static loading tests or stress wave analyses can be employed to estimate the axial capacity of single piles. Both laboratory and field tests show that soil exhibits time-dependent behaviour. An important result...... based on a set of static loading tests. In the literature it is suggested that the pile capacity increases with the logarithm to time after installation which is confirmed in this thesis. In continuation of this, it is analysed whether the magnitude of the set-up is related to the properties of the clay...... circumstances (e.g. load specifications, length of pile, pile material). In order to evaluate the design methods for piles in clay, it is necessary to correct for time between pile driving and pile testing. Results of testing the calculation procedures against the available data by employing different time...

  15. Analysis of Dynamic Stiffness of Bridge Cap-Pile System

    Directory of Open Access Journals (Sweden)

    Jinhui Chu

    2018-01-01

    Full Text Available In order to investigate the applicability of dynamic stiffness for bridge cap-pile system, a laboratory test was performed. A numerical model was also built for this type of system. The impact load was applied on the cap top and the dynamic stiffness was analysed. Then, the effect of the effective friction area between pile and soil was also considered. Finally, the dynamic stiffness relationship between the single pile and the cap-pile system was also compared. The results show that the dynamic stiffness is a sensitive index and can well reflect the static characteristics of the pile at the elastic stage. There is a significant positive correlation between the vertical dynamic stiffness index and bearing capacity of the cap-pile system in the similar formation environment. For the cap-pile system with four piles, the dynamic stiffness is about four times as large as the single pile between 10 and 20 Hz.

  16. Transformations des représentations de la violence dans le cadre scolaire: De la définition des experts à la définition des élèves

    OpenAIRE

    Clémence, Alain

    2004-01-01

    Nous présentons une recherche sur la violence dans le contexte scolaire réalisée en Suisse romande. L'orientation théorique est fondée sur la transformation de la représentation sociale de la violence dans les analyses expertes et ordinaires de l'agression. Différentes définitions de la violence sont discutées dans une perspective développementale de l'identité sociale et des dynamiques des relations scolaires. Les résultats montrent que la représentation de la violence et des actes d'agressi...

  17. Dispositifs permanents pour le suivi des forêts en Afrique Centrale : un état des lieux

    OpenAIRE

    Picard , Nicolas

    2007-01-01

    38 p.; Cette étude, réalisée dans le cadre d'une convention entre la Commission des Forêts d'Afrique Centrale (COMIFAC) et le Centre de Coopération Internationale en Recherche Argonomique pour le Développement (CIRAD), département Environnements et Sociétés, vise à faire un état des lieux en matière de dispositifs permanents de suivi de la dynamique forestière dans les forêts du bassin du Congo. Elle est la première étape d'une étude visant à définir un protocole de mise en place de dispositi...

  18. Pile foundation of nuclear power plant structures

    International Nuclear Information System (INIS)

    Jurkiewicz, W.J.; Thomaz, E.; Rideg, P.; Girao, M.

    1978-01-01

    The subject of pile foundation used for nuclear power plant structures, considering the experience gained by the designers of the Angra Nuclear Power Plant, Units 2 and 3 in Brazil is dealt with. The general concept of the pile foundations, including types and execution of the piles, is described briefly. Then the two basic models, i.e. the static model and the dynamic one, used in the design are shown, and the pertinent design assumptions as related to the Angra project are mentioned. The criteria which established the loading capacity of the piles are discussed and the geological conditions of the Angra site are also explained briefly, justifying the reasons why pile foundations are necessary in this project. After that, the design procedures and particularly the tools - i.e. the computer programs - are described. It is noted that the relatively simple but always time consuming job of loading determination calculations can be computerized too, as it was done on this project through the computer program SEASA. The interesting aspects of soil/structure interaction, applicable to static models, are covered in detail, showing the theoretical base wich was used in the program PILMAT. Then the advantage resulting from computerizing of the job of pile reinforcement design are mentioned, describing briefly the jobs done by the two special programs PILDES and PILTAB. The point is stressed that the effort computerizing the structural design of this project was not so much due to the required accuracy of the calculations, but mainly due to the need to save on the design time, as to allow to perform the design task within the relatively tight time schedule. A conclusion can be drawn that design of pile foundations for nuclear power plant structures is a more complex task than the design of bearing type of foundation for the same structures, but that the task can be always made easier when the design process can be computerized. (Author)

  19. Measurement and Analysis of Horizontal Vibration Response of Pile Foundations

    Directory of Open Access Journals (Sweden)

    A. Boominathan

    2007-01-01

    Full Text Available Pile foundations are frequently used in very loose and weak deposits, in particular soft marine clays deposits to support various industrial structures, power plants, petrochemical complexes, compressor stations and residential multi-storeyed buildings. Under these circumstances, piles are predominantly subjected to horizontal dynamic loads and the pile response to horizontal vibration is very critical due to its low stiffness. Though many analytical methods have been developed to estimate the horizontal vibration response, but they are not well validated with the experimental studies. This paper presents the results of horizontal vibration tests carried out on model aluminium single piles embedded in a simulated Elastic Half Space filled with clay. The influence of various soil and pile parameters such as pile length, modulus of clay, magnitude of dynamic load and frequency of excitation on the horizontal vibration response of single piles was examined. Measurement of various response quantities, such as the load transferred to the pile, pile head displacement and the strain variation along the pile length were done using a Data Acquisition System. It is found that the pile length, modulus of clay and dynamic load, significantly influences the natural frequency and peak amplitude of the soil-pile system. The maximum bending moment occurs at the fundamental frequency of the soil-pile system. The maximum bending moment of long piles is about 2 to 4 times higher than that of short piles and it increases drastically with the increase in the shear modulus of clay for both short and long piles. The active or effective pile length is found to be increasing under dynamic load and empirical equations are proposed to estimate the active pile length under dynamic loads.

  20. Dynamic method for the measurement of Young'S modulus. Application to nuclear graphites; Methode de mesure dynamique du module d'Young. Application aux graphites nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Pattou, F; Trutt, J C

    1963-07-01

    A dynamic method has been developed for measuring Young's modulus and the rigidity modulus using the 'Forster Elastomat'. The principle consists in the determination of the resonance frequencies of graphite samples submitted to transverse, longitudinal, and torsional vibrations. The first two modes of vibration make it possible to calculate the elasticity modulus or the Young's modulus E, the third mode makes possible the calculation of the rigidity modulus G. The relationships from which the moduli E and G are measured are given. A systematic study has been made of graphite samples produced by extrusion or compression and submitted afterwards to one or several impregnations with pitch. For graphites made from the same coke by the same method, a linear relationship has been found for Young's modulus as a function of the apparent density. For the same apparent density, graphites made from different starting materials have generally different Young's moduli that bear a relationship to the crystalline characteristics of the material. The measurements of the rigidity modulus C made on different graphites also show the influence of crystallite orientation. (authors) [French] Une methode de mesure dynamique du module d'Young et du module de rigidite du graphite utilisant 'l'Elastomat Forster' a ete mise au point. Le principe consiste a determiner les frequences de resonance d'echantillons de graphite soumis a des vibrations transversales, longitudinales et de torsion. Les deux premiers modes de vibration permettent de calculer le module d'elasticite ou module d'Young E, le troisieme mode de vibration permet de calculer le module de rigidite G. Apres avoir decrit la methode de mesure, on rappelle les relations qui permettent de calculer les modules E et G. L'etude systematique d'echantillons de graphite, fabriques par filage ou pressage et ayant subi eventuellement une ou plusieurs impregnations au brai a ete effectuee. Pour les graphites issus du meme coke et fabriques

  1. The purification by ion exchange resins of the heavy water la the reactors EL1 and EL2. B - study of the general properties of the resins used; Purification par resines echangeuses d'ions de l'eau lourde de reacteurs EL1 et EL2. B - etude des proprietes generales des resines utilisees

    Energy Technology Data Exchange (ETDEWEB)

    Fourre,; Platzer, [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    Within the programme of the pile heavy water purification project, organized by the stable Isotopes Section, we have carried out a certain number of tests on ion exchange resins. The problem posed by the stable Isotopes Section was to determine the conditions of utilisation of ion exchange resins, knowing that they would be employed in a system branching off the heavy water circuit in the piles. These investigations were carried out in close collaboration with the stable Isotopes Section, and were guided chiefly by the extremely short delay permitted between the laboratory study and its application to the piles. The tests are divided into two groups: 1- General properties of the resins. 2- Utilisation of the resins, particularly in an apparatus similar to those mounted on the piles but of smaller dimensions. (author) [French] Dans le cadre du projet d'epuration de l'eau lourde des piles, traite par la Section des Isotopes stables, nous avons fait un certain nombre d'essais sur les resines echangeuses d'ions. Le probleme pose par la Section des Isotopes stables etait de determiner les conditions d'utilisation des resines echangeuses d'ions sachant qu'elles devraient etre employees dans un appareil place en derivation sur le circuit d'eau lourde des piles. L'ensemble de l'etude a ete mene en collaboration etroite avec la Section des Isotopes stables et a ete guide principalement par le delai extremement court dans lequel l'etude de laboratoire devait etre appliquee aux piles. Les essais se divisent en deux groupes: 1- Proprietes generales des resines. 2- Utilisation des resines, en particulier dans un appareil analogue a ceux montes sur les piles, mais de dimensions reduites. (auteur)

  2. Test Procedure for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test procedure described in the following is used when examining the effects of static or cyclic loading on the skin friction of an axially loaded pile in dense sand. The pile specimen is only loaded in tension to avoid any contribution from the base resistance. The pile dimensions are chosen...... to resemble full scale dimension of piles used in offshore pile foundations today. In this report is given a detailed description of the soil preparation and pile installation procedures as well data acquisition methods....

  3. Pile Design Based on Cone Penetration Test Results

    OpenAIRE

    Salgado, Rodrigo; Lee, Junhwan

    1999-01-01

    The bearing capacity of piles consists of both base resistance and side resistance. The side resistance of piles is in most cases fully mobilized well before the maximum base resistance is reached. As the side resistance is mobilized early in the loading process, the determination of pile base resistance is a key element of pile design. Static cone penetration is well related to the pile loading process, since it is performed quasi-statically and resembles a scaled-down pile load test. In ord...

  4. Seismic behavior analysis of piled drums

    International Nuclear Information System (INIS)

    Aoki, H.; Kosaka, T.; Mizushina, T.; Shimizu, M.; Uji, S.; Tsuchiya, H.

    1987-01-01

    In general, low level radioactive waste is packed in drums and stored in a warehouse being piled vertically, or laid horizontally. To observe the behavior of piled drums during an earthquake, an experimental study was reported. The experimental study is limited by the vibrating platform capacity. To carry out these tests up to the supporting limit is not recommended, in view of the vibrating platform curing as well as the operators' security. It is very useful to develop the analytical method for simulating the behavior of the drums. In this report, a computer program of piled drum's dynamic motion is shown, and the analytical result is referred to the experimental result. From the result of experiment on piled drums, the sliding effect has been found to be very important for the stability of drum, and the rocking motion observed, showing a little acceleration is less than the static estimated value. Behavior of piled drums is a complex phenomena comprising of sliding, rocking and jumping

  5. Three dimensional analysis of laterally loaded piles

    International Nuclear Information System (INIS)

    Yilmaz, C.

    1987-01-01

    In this study static analysis of laterally loaded pile is studied by the three models. The first model is the beam on discrete elastic springs. This model is analyzed using a flexibility method. The second model is the beam on a two-parameter elastic foundation. This model is analyzed using the linear finite element method. The third model is the finite element model, using the three-dimensional iso-parametric parabolic brick element. Three-dimensional pile group analysis is also performed using elastic constants of single pile obtained by any one of the above analyses. The main objective is to develop computer programs for each model related to single piles and to group analysis. Then, the deflections, rotations, moments, shears, stresses and strains of the single pile are obtained at any arbitrary point. Comparison is made between each model and with other studies such as Poulos 1971, Desai and Appel 1976. In addition, to provide a benchmark of three-dimensional finite element analysis, the Boussinesq problem is analyzed. (orig.)

  6. Etude exploratoire des conceptions de la circulation sanguine aupres d'eleves de l'ordre collegial

    Science.gov (United States)

    Robitaille, Jean-Marc

    Il existe peu d'etudes sur les conceptions touchant les domaines de la biologie, notamment sur les conceptions de la circulation sanguine Nous avons observe egalement l'absence de recherche menee aupres d'eleves de l'ordre collegial sur cette question. Nous avons voulu combler une lacune en menant une recherche sur les conceptions de la circulation sanguine aupres d'eleves de l'ordre collegial. Pour mener cette recherche nous nous sommes inspires d'une methode developpee par Treagust (1988). Le premier niveau de formulation didactique etablit l'architecture du systeme et la fonction nutritive de la circulation. Le second niveau de formulation didactique decrit et relie les parametres de la dynamique de la circulation et leur relation: Pression, Debit et Resistance. Le troisieme niveau de formulation didactique s'interesse au controle de la circulation du sang dans un contexte d'homeostasie qui implique la regulation de la pression arterielle. Nous avons construit un questionnaire en nous guidant sur les niveaux de formulation didactique et l'analyse des entrevues menees aupres de dix-huit eleves, representatifs de la population cible. Ce questionnaire fut administre a un echantillon de 2300 eleves disperses dans six colleges de la region de Montreal. Notre echantillon comprend des eleves inscrits a des programmes de l'ordre collegial en Sciences de la nature et en Techniques de la sante et qui n'ont pas suivi le cours sur la circulation sanguine. Notre analyse des reponses des eleves de notre echantillon aux questions sur le premier niveau de formulation didactique revele que la majorite des eleves considerent que le systeme circulatoire relie les organes les uns aux autres dans un circuit en serie. Notre analyse revele egalement que la majorite des eleves estiment que les nutriments sont extraits du sang par les organes selon un processus de selection base sur les besoins determines par la fonction de l'organe. Ces besoins sont differents selon les organes qui ne

  7. Dislocational Rock Mechanisms As a Basis for Seismic Methods in the Search for Hydrocarbons La géomécanique de dislocation en tant que base des méthodes sismiques de la recherche des hydrocarbures

    Directory of Open Access Journals (Sweden)

    Pissetski V. B.

    2006-11-01

    témoigne de l'importance prédominante des déplacements verticaux dans de tels milieux et, par conséquent, le caractère de blocs de la distribution des charges par un schéma de compensation. Ainsi, l'élément central dans le modèle de milieu discret dont on parle est la structure de fissuration (dislocation et la distribution caractéristique de l'état de contrainte (pression. Il est évident que dans de tels modèles de systèmes discrets les principaux paramètres des processus liés au fluide seront déterminés par la densité de dislocation et la grandeur de la pression générale opérant sur ce volume de milieu. Avec cela la pression générale est définie comme la somme de la pression lithostatique et de la pression anomalique où le terme de pression anomalique dans le cas précis reflète la variabilité caractéristique de l'état de tension des systèmes discrets ayant un soubassement mobile. En tenant compte de ces conditions le milieu considéré est défini comme un modèle de dislocation fluidique (DFM. Dans le modèle DFM la nature de la variabilité des propriétés physiques dans un espace réel de série sédimentaire est défini - en premier par la valeur du volume du milieu considéré - en second par la densité de dislocations et la valeur de la pression, et seulement - en troisième par les propriétés de chaque briquedont la pluralité constitue le milieu. Le résultat des études théoriques et expérimentales du processus de propagation des ondes élastiques dans le DFM nous amène à une interprétation complètement différente de la nature et des propriétés des limites sismiques : les réflecteurs physiques réels d'ondes élastiques sont les surfaces de dislocation tandis que les paramètres dynamiques de réflexion sont formés par la valeur de la pression agissant sur la surface de dislocation donnée ou l'ensemble des dislocations dans le volume d'onde observé de l'espace. Ainsi, la formulation des problèmes inverses

  8. Une prospective pour la filière française des vins biologiques

    Directory of Open Access Journals (Sweden)

    Aigrain Patrick

    2017-01-01

    Full Text Available La viticulture biologique française est une filière dynamique. Si certaines évolutions de la demande de bio sont similaires à celles observées pour le vin conventionnel (rosé, Bag-in-box, …, d'autres comme la demande de vins sans sulfites ou de vins « vegan » interpellent plus spécifiquement ce segment. La filière des vins bio se trouve à la fois devoir respecter la règlementation viticole et celle de la production en bio, que ce soit par le cahier des charges de production de la matière première « raisin » que de sa transformation en vin. Elle doit satisfaire des consommateurs exigeants et fédérer des producteurs passionnés parfois jusqu'à l'excès. Face à cette forte dynamique de développement soutenue par une demande qui contourne partiellement les circuits classiques de distribution, la filière française des vins bio (France Vins Bio a souhaité mener un exercice de prospective conduit par FranceAgriMer et Montpellier SupAgro. La présente communication va présenter, après un rappel des grands principes et de la méthode de prospective utilisée, les thématiques explorées, les principales hypothèses combinées et l'essentiel des scénarios sur lesquels elles débouchent.

  9. Optimal sizes and siting of nuclear fuel reprocessing plants; Tailles et localisations optimales des usines de retraitement des combustibles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L; Deledicq, A [Commissariat a l' Energie Atomique, Siege (France). Centre d' Etudes Nucleaires

    1967-07-01

    traite le probleme des usines de traitement de l'uranium naturel irradie associees a des centrales nucleaires a uranium naturel-graphite CO{sub 2}. La localisation et la production annuelle des reacteurs, les sites possibles d'usines et les fonctions de cout (transport et retraitement) sont supposes connus. La methode consiste a traiter d'abord le probleme des usines de traitement comme un probleme de programmation dynamique, des tranches croissantes de programmes (production totale des reacteurs) etant explorees sequentiellement. Lorsque les quantites d'uranium naturel irradie a retraiter sont fixees, la minimisation du cout de transport est alors effectuee, elle aussi comme un probleme de programmation dynamique. On explore le voisinage de l'optimum du cout de traitement pour trouver le minimum de la somme d'un cout de traitement sous-optimal et du cout de transport optimal correspondant. Le probleme de retraitement etant representable sur un graphe sequentiel, l'algorithme utilise pour calculer les sous-optima est 'l'algorithme a reflexion' que nous avons elabore. La methode s'interprete comme un mecanisme general de determination de l'optimum lorsque, a un probleme dynamique sequentiel (par exemple un programme d'equipement), se superpose un probleme complementaire (par exemple de transport). Elle permet en outre d'evaluer les pertes resultant du choix, pour des raisons autres qu'economiques, d'une politique non optimale. (auteur)

  10. Tables of formulae for calculating the mechanics of stacks in gas-graphite reactors; Formulaire pour le calcul de la mecanique des empilements des reacteurs graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1968-07-01

    This collection of formulae only gives, for nuclear graphite stacks. The mechanical effects due to the strains, thermal or not, of steel structures supporting or surrounding graphite blocks. Equations have been established by mean of experiments made at Chinon with large pile models. Thus, it is possible to calculate displacement, strain and stress in the EDF type stacks of horizontal triangular block lattice. (authors) [French] Le domaine de ce formulaire est strictement limite aux effets mecaniques, pour les empilements, des deformations, thermiques ou autres, des structures metalliques de soutien (aire - support et corset). On propose un ensemble de relations qui ont ete etablies a la suite des essais de CHINON sur des maquettes de grande taille. Ces relations permettent le calcul des mouvements, des deformations et des contraintes dans les empilements du type EDF, a reseau horizontal triangulaire regulier. (auteurs)

  11. In pile helium loop ''Comedie''

    International Nuclear Information System (INIS)

    Blanchard, R.J.

    1985-01-01

    The loop is located in the SILOE reactor at Centre d'Etudes Nucleaires de Grenoble. The purpose and objectives are divided into two groups, principal and secondary. The primary objective was to provide basic data on the deposition behavior of important condensable fission products on a variety of steel surfaces, i.e. temperature (sorption isotherms) and mass transfer (physical adsorption) dependencies; to provide information concerning the degree of penetration of important fission products into the metals comprising the heat exchanger-recuperator tubes as a function of alloy type and/or metal temperature; to provide complementary information on the reentrainment (liftoff) of important fission and activation products by performing out-of-pile blowdown experiments on tube samples representative of the alloy types used in the heat exchanger-recuperator and of the surface temperatures experienced during plateout. The secondary objective was to provide information concerning the migration of important fission products through graphite. To this end, concentration profiles in the web between the fuel rods containing the fission product source and the coolant channels and in the graphite diffusion sample will be measured to study the corrosion of metallic specimens placed in the conditions of high temperature gas cooled reactor. The first experiment SRO enables to determine the loop characteristics and possibilities related to thermal, thermodynamic, chemical and neutronic properties. The second experiment has been carried out in high temperature gas cooled reactor operating conditions. It enables to determine in particular the deposition axial profile of activation and fission products in the plateout section constituting the heat exchanger, the fission products balance trapped in the different filter components, and the cumulated released fraction of solid fission products. The SR1 test permits to demonstrate in particular the Comedie loop operation reliability, either

  12. Utilisation d'une sonde fluorimétrique benthique (la BenthoTorch, bbe) pour mesurer la croissance des diatomées, algues vertes et cyanobactéries périphytiques en plans d'eau

    OpenAIRE

    Roubeix, V.

    2015-01-01

    / Une sonde fluorimétrique benthique, la BenthoTorch (bbe) a été acquise par le pôle Onema-Irstea d'Hydroécologie des Plans d'eau pour développer un indice fonctionnel de production primaire dans les plans d'eau. Cet indice sera basé sur la dynamique de croissance du périphyton sur des substrats artificiels. Il constituerait un outil de diagnostic du fonctionnement écologique des systèmes lentiques, particulièrement utile dans le cadre du suivi de mesures de restauration. La BenthoTorch me...

  13. Modelling of Molecular Structures and Properties in Physical Chemistry and Biophysics, Forty-Fourth International Meeting (Modelisation des Structures et Proprietes Moleculaires en Chimie Physique et en Biophysique, Quarante- Quatrieme Reunion Internationale)

    Science.gov (United States)

    1989-09-01

    apprcc-he novatzice, fondde sur une perception de I’ envixcnnmnt local des atoi-es dolt of frir des resssources inr~rtantes dans le traitement de tous les...Acta, 72, 1-13 (1989). 2586 Etude thdorique de la structure du compiexe Giutathion - Eau oxygdn4e J.Berg~s , JCaillet Dynamique des Interactions Mol...est connu que !a r6action d’oxydati4on du glutathion par 1! eau oxyg~n6e est catalys~e, in vivo, par une enzyme, la glutathion peroxydase. I’l a4t

  14. Fuel slugs considered for use in the high flux reactor EL3; Elements combustibles envisages pour la pile a haut flux EL 3

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Caillat, R; Gauthron, M; Montagne, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    EL3 was designed essentially for the study, under irradiation conditions, of materials used in the construction of atomic reactors. The study schedule allocates considerable time and effort to new types of fuel slugs. The present report described the various types of slug being tested or scheduled for tests. After laboratory study, each slug is tested in an experimental cell in the pile. The best are retained and used to charge the reactor (the present charge is purely provisional to permit first criticality and power rise tests)ren. [French] La pile EL3 est essentiellement destinee a l'etude sous irradiation des materiaux utilises dans la construction des reacteurs atomiques. Dans ce programme, une tres large part est reservee a l'etude de nouveaux elements combustibles. Le present rapport decrit les differentes solutions de cartouches dont l'essai est envisage ou en cours. Apres etude en laboratoire, chacune de ces solutions est testee dans une cellule experimentale en pile. Les meilleures seront retenues pour constituer le chargement normal de la pile (le chargement actuel etant essentiellement une solution provisoire qui a permis la divergence de la pile et les premiers essais de montee en puissance). (auteur)

  15. Picking up Clues from the Discard Pile

    Science.gov (United States)

    2008-01-01

    As NASA's Phoenix Mars Lander excavates trenches, it also builds piles with most of the material scooped from the holes. The piles, like this one called 'Caterpillar,' provide researchers some information about the soil. On Aug. 24, 2008, during the late afternoon of the 88th Martian day after landing, Phoenix's Surface Stereo Imager took separate exposures through red, green and blue filters that have been combined into this approximately true-color image. This conical pile of soil is about 10 centimeters (4 inches) tall. The sources of material that the robotic arm has dropped onto the Caterpillar pile have included the 'Dodo' and ''Upper Cupboard' trenches and, more recently, the deeper 'Stone Soup' trench. Observations of the pile provide information, such as the slope of the cone and the textures of the soil, that helps scientists understand properties of material excavated from the trenches. For the Stone Soup trench in particular, which is about 18 centimeters (7 inches) deep, the bottom of the trench is in shadow and more difficult to observe than other trenches that Phoenix has dug. The Phoenix team obtained spectral clues about the composition of material from the bottom of Stone Soup by photographing Caterpillar through 15 different filters of the Surface Stereo Imager when the pile was covered in freshly excavated material from the trench. The spectral observation did not produce any sign of water-ice, just typical soil for the site. However, the bigger clumps do show a platy texture that could be consistent with elevated concentration of salts in the soil from deep in Stone Soup. The team chose that location as the source for a soil sample to be analyzed in the lander's wet chemistry laboratory, which can identify soluble salts in the soil. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed

  16. Analyse des solides déformables par la méthode des éléments finis

    CERN Document Server

    Bonnet, Marc

    2006-01-01

    Cet ouvrage propose une présentation structurée de la formulation et la mise en œuvre de la simulation numérique par éléments finis en mécanique des solides déformables. Il présente et développe les concepts et techniques permettant la transposition, en termes de codes de calcul de structures mécaniques industrielles, des notions fondamentales de mécanique des milieux continus solides, et ce dans le cadre d'analyses en régimes (a) statique linéaire, (b) quasistatique non-linéaire et (c) dynamique linéaire. L'exposé théorique est complété et illustré au moyen de programmes d'initiation écrits en Matlab (librement accessibles par Internet) mettant en œuvre les notions développées dans cet ouvrage et conçus comme support pratique à un enseignement. Le texte combine ainsi l'exposition des principes et des méthodes avec la présentation détaillée de ces programmes et d'exemples les mettant en œuvre. L'ouvrage est complété d'une annexe écrite par Andrei Constantinescu (directeur de...

  17. Synthesis of concrete bridge piles prestressed with CFRP systems.

    Science.gov (United States)

    2017-06-01

    The Texas Department of Transportation frequently constructs prestressed concrete piles for use in bridge : foundations. Such prestressed concrete piles are typically built with steel strands that are highly susceptible to : environmental degradation...

  18. Laboratory Test Setup for Cyclic Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2017-01-01

    This paper presents a comprehensive description and the considerations regarding the design of a new laboratory test setup for testing cyclic axially loaded piles in sand. The test setup aims at analysing the effect of axial one-way cyclic loading on pile capacity and accumulated displacements....... Another aim was to test a large diameter pile segment with dimensions resembling full-scale piles to model the interface properties between pile and sand correctly. The pile segment was an open-ended steel pipe pile with a diameter of 0.5 m and a length of 1 m. The sand conditions resembled the dense sand...... determined from the API RP 2GEO standard and from the test results indicated over consolidation of the sand. Two initial one-way cyclic loading tests provided results of effects on pile capacity and accumulated displacements in agreement with other researchers’ test results....

  19. Radiation Protection in the Experimental Pile Marius

    International Nuclear Information System (INIS)

    Cohendy, G.

    1962-01-01

    Measurements made around the experimental pile 'Marius' made it possible to determine the valid characteristics of the slabs designed to improve the biological protection by covering the charge and discharge pits. These measurements also made it possible to evaluate the risks occurring when the pile is operating at various Powers and to make a reasonable estimate of the value of the ratio of the total danger due to neutrons (thermal and fast) and γ radiation and to the danger due only to the γ radiation. A knowledge of this ratio makes it possible to make satisfactory evaluations with a single apparatus which is really portable. (author) [fr

  20. Piles of dislocation loops in real crystals. 2. Evolution of dislocation piles under irradiation

    International Nuclear Information System (INIS)

    Dubinko, V.I.; Turkin, A.A.; Yanovskij, V.V.

    1985-01-01

    The given paper considers evolution of piles in a real molybdenum crystal under neutron irradiation. Obtained was a stability criterium, when meeting it interstitial piles (one-dimensional periodical structures of interstitial loops) in the crystal tend to stationary state under the irradiation and, when disturbing the criterium, they disintegrate into rapidly growing interstitial isolated loops. It was also shown that the generation of dense vacancy piles results in the formation of an ordering structure of isolated vacancy loops. Theoretical results agree good with experimental data

  1. Summary on out-of-pile and in-pile properties of M5 alloy

    International Nuclear Information System (INIS)

    Zhao Wenjin

    2001-01-01

    The out-of-pile and in-pile corrosion, mechanical properties, microstructure,hydrogen absorption, creep and growth resistances of M5 alloy using as PWR fuel rod cladding materials developed by FRAMATOME in France has been summarized with reference to the literatures. The results obtained from in-pile irradiation tests show that the corrosion and hydrogen absorption resistances, creep and irradiation growth resistances of M5 alloy cladding are superior to that of the optimized Zircaloy-4. It could be estimated that the M5 alloy enables rod burnups close to 65GWd/tU to be reached

  2. Le passage à l'acte meurtrier dans Ies organisations psychotiques et non-psychotiques: Etude des significations à travers l'interaction des facteurs intrapsychique, intersubjectif et moral

    OpenAIRE

    Hirschelmann-Ambrosi, Astrid

    1999-01-01

    Tese de Doutoramento em Psicologia, especialidade em Psicopatologia, apresentada À Université Toulouse Le Miral La présente recherche s'intéresse au phénomène criminel et trouve son origine dans un double constat ; d'un côté, celui d'une varlabilité des significations que prend un même type d’acte et de 1'autre, celui d’une varlabilité des effets de la causalité interne, et plus précisément des processus psychiques des sujets criminels. S'en dégage alors clairement 1'idée d'une dynamique i...

  3. Analysis of radon protection cover on uranium tailings pile

    International Nuclear Information System (INIS)

    Zhang Zhe

    1993-01-01

    The average radon emanation rate of the whole surface over one year was used for evaluating the radon release of uranium tailings pile. The effective of radon protection cover depends on the shape and property of the tailings pile, the properties of covering and the control of air vadose in the pile. It was indicated that the covering with low diffusion coefficient, small porosity and bad permeability was suitable to cover the pile. The analytical formula of the covering layer thickness was given

  4. Pile group program for full material modeling and progressive failure.

    Science.gov (United States)

    2008-12-01

    Strain wedge (SW) model formulation has been used, in previous work, to evaluate the response of a single pile or a group of piles (including its : pile cap) in layered soils to lateral loading. The SW model approach provides appropriate prediction f...

  5. 29 CFR 1926.603 - Pile driving equipment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Pile driving equipment. 1926.603 Section 1926.603 Labor... Operations § 1926.603 Pile driving equipment. (a) General requirements. (1) Boilers and piping systems which are a part of, or used with, pile driving equipment shall meet the applicable requirements of the...

  6. 30 CFR 77.215-3 - Refuse piles: certification.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles: certification. 77.215-3 Section... COAL MINES Surface Installations § 77.215-3 Refuse piles: certification. (a) Within 180 days following written notification by the District Manager that a refuse pile can present a hazard, the person owning...

  7. Interacting with piles of artifacts on digital tables

    NARCIS (Netherlands)

    Aliakseyeu, D.; Lucero Vera, A.A.; Subramanian, S.

    2007-01-01

    Designers and architects regularly use piles to organise visual artifacts. Recent efforts have now made it possible for users to create piles in digital systems as well. However, there is still little understanding of how users shouldinteract with digital piles. In this paper we investigate this

  8. Design Optimization of Piles for Offshore Wind Turbine Jacket Foundations

    DEFF Research Database (Denmark)

    Sandal, Kasper; Zania, Varvara

    Numerical methods can optimize the pile design. The aim of this study is to automatically design optimal piles for offshore wind turbine jacket foundations (Figure 1). Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil...

  9. 30 CFR 77.215-1 - Refuse piles; identification.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; identification. 77.215-1 Section... COAL MINES Surface Installations § 77.215-1 Refuse piles; identification. A permanent identification marker, at least six feet high and showing the refuse pile identification number as assigned by the...

  10. 30 CFR 77.215-2 - Refuse piles; reporting requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; reporting requirements. 77.215-2... COAL MINES Surface Installations § 77.215-2 Refuse piles; reporting requirements. (a) The proposed location of a new refuse pile shall be reported to and acknowledged in writing by the District Manager...

  11. 30 CFR 77.215 - Refuse piles; construction requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; construction requirements. 77.215... COAL MINES Surface Installations § 77.215 Refuse piles; construction requirements. (a) Refuse deposited on a pile shall be spread in layers and compacted in such a manner so as to minimize the flow of air...

  12. Interacting with piles of artifacts on digital tables

    NARCIS (Netherlands)

    Aliakseyeu, D.; Subramanian, S.; Lucero Vera, A.A.; Gutwin, C.

    2006-01-01

    Designers and architects regularly use piles to organize visual artifacts. Recent efforts have now made it possible for users to create piles in digital systems as well. However, there is still little understanding of how users should interact with digital piles. In this paper we investigate this

  13. Probabilistic model of random uncertainties in structural dynamics for mis-tuned bladed disks; Modele probabiliste des incertitudes en dynamique des structures pour le desaccordage des roues aubagees

    Energy Technology Data Exchange (ETDEWEB)

    Capiez-Lernout, E.; Soize, Ch. [Universite de Marne la Vallee, Lab. de Mecanique, 77 (France)

    2003-10-01

    The mis-tuning of blades is frequently the cause of spatial localizations for the dynamic forced response in turbomachinery industry. The random character of mis-tuning requires the construction of probabilistic models of random uncertainties. A usual parametric probabilistic description considers the mis-tuning through the Young modulus of each blade. This model consists in mis-tuning blade eigenfrequencies, assuming the blade modal shapes unchanged. Recently a new approach known as a non-parametric model of random uncertainties has been introduced for modelling random uncertainties in elasto-dynamics. This paper proposes the construction of a non-parametric model which is coherent with all the uncertainties which characterize mis-tuning. As mis-tuning is a phenomenon which is independent from one blade to another one, the structure is considered as an assemblage of substructures. The mean reduced matrix model required by the non-parametric approach is thus constructed by dynamic sub-structuring. A comparative approach is also needed to study the influence of the non-parametric approach for a usual parametric model adapted to mis-tuning. A numerical example is presented. (authors)

  14. Nouvelles approches en theorie du champ moyen dynamique: le cas du pouvoir thermoelectrique et celui de l'effet orbital d'un champ magnetique

    Science.gov (United States)

    Arsenault, Louis-Francois

    Les applications reliees a la generation d'energie motivent la recherche de materiaux ayant un fort pouvoir thermoelectrique (S). De plus, S nous renseigne sur certaines proprietes fondamentales des materiaux, comme, par exemple, la transition entre l'etat coherent et incoherent des quasi-particules lorsque la temperature augmente. Empiriquement, la presence de fortes interactions electron-electron peut mener a un pouvoir thermoelectrique geant. Nous avons donc etudie le modele le plus simple qui tient compte de ces fortes interactions, le modele de Hubbard. La theorie du champ moyen dynamique (DMFT) est tout indiquee dans ce cas. Nous nous sommes concentres sur un systeme tridimensionnel (3d) cubique a face centree (fcc), et ce, pour plusieurs raisons. A) Ce type de cristal est tres commun dans la nature. B) La DMFT donne de tres bons resultats en 3d et donc ce choix sert aussi de preuve de principe de la methode. C) Finalement, a cause de la frustration electronique intrinseque au fcc, celui-ci ne presente pas de symetrie particule-trou, ce qui est tres favorable a l'apparition d'une grande valeur de S. Ce travail demontre que lorsque le materiau est un isolant a demi-remplissage a cause des fortes interactions (isolant de Mott), il est possible d'obtenir de grands pouvoirs thermoelectriques en le dopant legerement. C'est un resultat pratique important. Du point de vue methodologique, nous avons montre comment la limite de frequence infinie de S et l'approche dite de Kelvin, qui considere la limite de frequence nulle avant la limite thermodynamique pour S, donnent des estimations fiables de la vraie limite continue (DC) dans les domaines de temperature appropriee. Ces deux approches facilitent grandement les calculs en court-circuit ant la necessite de recourir a de problematiques prolongements analytiques. Nous avons trouve que la methode de calcul a frequence infinie fonctionne bien lorsque les echelles d'energie sont relativement faibles. En d'autres termes

  15. Some particular aspects of control in nuclear power reactors; Quelques aspects particuliers du controle dans les piles atomiques de puissance

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Pupponi, J [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    There are still many problems in the field of measurement and control of neutron flux. The present studies in connexion with high flux reactors contribute to the solution of these problems which concern specialists in reactor control. The present state of this investigation and the results of different studies carried out in France by the C A and the EDF are pointed out: A - In the nuclear instrumentation field, work is at present devoted to the technologies used to develop detectors and cables, which have to work at high temperature and in a high {gamma} background; fast electronic techniques are applied to fission counters to measure low neutron fluxes in a high {gamma} background (10 Rh). B - In the control and safety field, there is a real need for studies on the behaviour of reactors in the subcritical state. This increases the margin of security during restarts when poison effects must be overcome The perturbations due to control rod movements necessitate a new organisation of power level safety and control assemblies, in connexion with thermal or activation measurements. Two methods of fast start-up are described. They are related to the fission rate measurement as a function of time. This is done either continuously by a constant and high reactivity change, or step by step. The application of automatic techniques to detector motion seems to give the answer to control and safety in normal start-up. C - The scope of these studies covers the methods used for the control of E.D.F. 3, which are described. (authors) [French] La mesure et le controle du flux neutronique dans les piles de puissance posent encore de nombreux problemes. Les etudes actuellement entreprises dans le domaine des piles a haut flux, doivent apporter une contribution importante a la solution de ces problemes qui interessent les specialistes du controle des piles de puissance. On analyse l'etat actuel de ces etudes et on donne les resultats des differents travaux effectues en France, dans

  16. Heterogeneous dipolar theory of the exponential pile

    International Nuclear Information System (INIS)

    Mastrangelo, P.V.

    1981-01-01

    We present a heterogeneous theory of the exponential pile, closely related to NORDHEIM-SCALETTAR's. It is well adapted to lattice whose pitch is relatively large (D-2O, grahpite) and the dimensions of whose channels are not negligible. The anisotropy of neutron diffusion is taken into account by the introduction of dipolar parameters. We express the contribution of each channel to the total flux in the moderator by means of multipolar coefficients. In order to be able to apply conditions of continuity between the flux and their derivatives, on the side of the moderator, we develop in a Fourier series the fluxes found at the periphery of each channel. Using Wronski's relations of Bessel's functions, we express the multipolar coefficients of the surfaces of each channel, on the side of the moderator, by means of the harmonics of each flux and their derivatives. We retain only monopolar (A 0 sub(g)) and dipolar (A 1 sub(g)) coefficients; those of a higher order are ignored. We deduce from these coefficients the systems of homogeneous equations of the exponential pile with monopoles on their own and monopoles plus dipoles. It should be noted that the systems of homogeneous equations of the critical pile are contained in those of the exponential pile. In another article, we develop the calculation of monopolar and dipolar heterogeneous parameters. (orig.)

  17. Underwater noise generated by offshore pile driving

    NARCIS (Netherlands)

    Tsouvalas, A.

    2015-01-01

    Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly

  18. Full size testing of sheet pile walls

    NARCIS (Netherlands)

    Kuilen, J.W.G. van de; Linden, M.L.R. van der; Katsma, H.; Stolle, P.

    1996-01-01

    Azobé (Lophira alata) is widely used in timber sheet pile walls in the Netherlands. The boards in these walls are coupled and therefore load-sharing can be expected. A simulation model based on the finite element method DIANA (DIANA, 1992) was developed and load-sharing could be calculated. To check

  19. Literature review Quasi-static and Dynamic pile load tests : Primarily report on non-static pile load tests

    NARCIS (Netherlands)

    Huy, N.Q.

    2010-01-01

    Pile testing, which plays an importance role in the field of deep foundation design, is performed by static and non-static methods to provide information about the following issues: (Poulos, 1998) - The ultimate capacity of a single pile. - The load-displacement behavior of a pile. - The performance

  20. Les territoires français à l'épreuve des mutations industrielles: Synthèse, Conclusions et Perspectives

    OpenAIRE

    Merenne-Schoumaker, Bernadette

    2015-01-01

    Cet article tente de dresser un bilan des travaux présentés dans le cadre de ce numéro thématique en s'appuyant sur quelques grands concepts : système productif, délocalisations/relocalisations, dynamiques territoriales (désindustrialisation, métropolisation et mondialisation/globalisation), innovation, gouvernance et capital humain et en s'interrogeant sur le rôle des territoires dans tous ces processus Peer reviewed

  1. Friction effects on lateral loading behavior of rigid piles

    DEFF Research Database (Denmark)

    Zania, Varvara; Hededal, Ole

    2012-01-01

    taking into account the shear frictional resistance along the pile. For this purpose efficient three dimensional finite element models of different diameter have been developed. The increase of the side friction and of the diameter of the pile is shown to alter the failure pattern and increase...... the lateral capacity of the pile. The obtained p - y curves demonstrate the importance of the aforementioned parameters in the design of rigid piles, as the reduction of friction along the interface reduces not only the ultimate load but also the stiffness of the soil-pile response. Read More: http...

  2. The Settlement Behavior of Piled Raft Interaction in Undrained Soil

    DEFF Research Database (Denmark)

    Ghalesari, Abbasali Taghavi; Barari, Amin; Amini, Pedram Fardad

    2013-01-01

    Offshore piled raft foundations are one of the most commonly used foundations in offshore structures. When a raft foundation alone does not satisfy the design requirements, the addition of piles may improve both the ultimate load capacity and the settlement performance of the raft. In this paper......, the behavior of a piled raft on undrained soil is studied based on a series of parametric studies on the average and differential settlement of piled raft using three-dimensional finite element analysis. The settlement behavior is found to be dependent on the number of piles and raft thickness....

  3. Integrity and As-built capacity of bored pile group

    International Nuclear Information System (INIS)

    Shaw, D.E.; Kissenpfennig, J.F.; Huemmer, M.R.

    1983-01-01

    This paper discusses the application of statistical methods to the reliability evaluation of cast-in-place concrete piles. The difficulties associated with pile construction can lead to larger uncertainties than would be associated with normal reinforced concrete structures both due to uncertainty in concrete quality and end bearing capacity. These uncertainties can be dealt with through the use of statistical methods. A statistical model of an individual pile is formulated along with a methodology for determining necessary statistical parameters from results of concrete batch tests, core strength tests and visual logs, sonic geophysical testing methods, and proof tests. Strength models for both static vertical and seismic horizontal loadings are discussed. The overall safety of a pile foundation is dependent upon the distribution of individual pile strength as well as the additional reliability due to the use of a large number of parallel load paths provided by a pile group foundation. The paper presents a mechanical model of global pile behavior which accounts for individual pile ductility along with the possibility of redistribution of loads from weaker to stronger piles. The use of the Monte Carlo method to determine the overall reliability of the pile foundation is discussed. Numerical results for both individual pile behavior as well as overall foundation behavior are presented. (orig.)

  4. Thermomechanical Behavior of Energy Pile Embedded in Sandy Soil

    Directory of Open Access Journals (Sweden)

    Xu Huang

    2018-01-01

    Full Text Available The traditional energy pile (solid energy pile has been implemented for decades. However, the design of different kinds of energy piles is still not well understood. In this study, a series of model tests were performed on an aluminum pipe energy pile (PEP in dry sandy soil to investigate the thermal effects on the mechanical behaviors of pipe energy pile. The thermal responses of the PEP were also analyzed. Steady temperatures of the PEP under different working conditions were also compared with that of the solid energy pile. Different loading tests were carried out on four pipe energy piles under three different temperatures of 5, 35, and 50°C, respectively. The bearing capacity change can be interpreted through the load-displacement curves. Experiment results were also compared with the solid energy pile to evaluate bearing capacities of the PEP and the solid energy pile under different temperature conditions. The mobilized shaft resistance was also calculated and compared with the solid energy pile data and the results show that the PEP has a similar load transfer mechanism with the solid energy pile. It could also be found that, for PEPs under working load, plastic displacement would appear after a whole heating cycle.

  5. Fast neutron flux in heavy water reactors; Flux de neutrons rapides dans les piles a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Brisbois, J; Katz, S [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France)

    1966-07-01

    The possibility of calculating the fast neutron flux in a natural uranium-heavy water lattice by superposition of the individual contributions of the different fuel elements was verified using a one-dimension Monte-Carlo code. The results obtained are in good agreement with experimental measurements done in the core and reflector of the reactor AQUILON. (author) [French] La possibilite de calculer le flux de neutrons rapides dans un reseau d'uranium naturel a eau lourde par superposition des apports des divers barreaux, a ete verifiee en utilisant un code Monte-Carlo monodimensionel. Les resultats obtenus concordent avec des mesures experimentales effectuees dans le coeur et reacteur de la pile Aquilon. (auteurs)

  6. Starting up a programme of atomic piles using compressed gas

    International Nuclear Information System (INIS)

    Horowitz, J.; Yvon, J.

    1959-01-01

    1) An examination of the intellectual and material resources which have directed the French programme towards: a) the natural uranium and plutonium system, b) the use of compressed gas as heat transfer fluid (primary fluid). 2) The parts played in exploring the field by the pile EL2 and G1, EL2 a natural uranium, heavy water and compressed gas pile, G1 a natural uranium, graphite and atmospheric air pile. 3) Development of the neutronics of graphite piles: physical study of G1. 4) The examination of certain problem posed by centres equipped with natural uranium, graphite and compressed carbon dioxide piles: structure, special materials, fluid circuits, maximum efficiency. Economic aspects. 5) Aids to progress: a) piles for testing materials and for tests on canned fuel elements, b) laboratory and calculation facilities. 6) Possible new orientations of compressed gas piles: a) raising of the pressure, b) enriched fuel, c) higher temperatures, d) use of heavy water. (author) [fr

  7. The Tensile Capacity Of Bored Piles In Frictional Soils

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Andersen, Allan; Damkilde, Lars

    2008-01-01

    Three series of 10 piles each were installed in two different locations. The length of the piles varied from 2 to 6 m and the diameters were 14 and 25 cm. The piles were constructed above the groundwater table using continuous flight augers and the concrete was placed by gravity free fall. The pi....... The piles were tested to failure in axial uplift and the load-displacement relations were recorded.......Three series of 10 piles each were installed in two different locations. The length of the piles varied from 2 to 6 m and the diameters were 14 and 25 cm. The piles were constructed above the groundwater table using continuous flight augers and the concrete was placed by gravity free fall...

  8. Full Scale Model Test of Consolidation Acceleration on Soft Soil deposition with Combination of Timber Pile and PVD (Hybrid Pile)

    OpenAIRE

    Sandyutama, Y.; Samang, L.; Imran, A. M.; Harianto4, T.

    2015-01-01

    This research aims to analyze the effect of composite pile-PVD (hybrid pile) as the reinforcement in embankment on soft soil by the means of numerical simulation and Full-Scale Trial Embankment. The first phase cunducted by numerical analysis and obtained 6-8 meters hybrid pile length effective. Full-Scale trial embankment. was installed hybrid pile of 6 m and preloading of 4,50 height. Full-scale tests were performed to investigate the performances of Hybrid pile reinforcement. This research...

  9. Study of the fluctuations in neutrons density in a homogeneous plutonium pile; Etude de la fluctuation de la population de neutrons sur une pile homogene au plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Clouet d' Orval, C; Deilgat, E; Labbe, J; Molbert, M; Tachon, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1962-07-01

    The variations in neutron density in the centre of a reactor core are subjected to a statistical fluctuation phenomenon. Because of the correlations existing between the neutrons, their distribution does not follow Poisson's law. It diverges from it by a quantity depending on various parameter such as the lifetime and the effective fraction of the slowed-down neutrons. Experiments have been carried out designed to demonstrate this divergence and also, more particularly, the correlation between unaffected and slowed-down neutrons; these have been carried out with the help of the reactor 'Proserpine', a critical homogeneous plutonium assembly. (author) [French] L'evolution de la population neutronique au sein d'un milieu multiplicateur est soumise a un phenomene de fluctuations statistiques. En raison des correlations qui existent entre les neutrons, leur distribution ne suit pas une loi de Poisson. Elle s'en ecarte d'une quantite qui depend de divers parametres tels que le temps de vie, la proportion effective des neutrons retardes. Des experiences, destinees a mettre en evidence cet ecart, et plus particulierement les correlations entre neutrons prompts et neutrons retardes, ont ete realisees a l'aide de la pile 'Proserpine', experience critique homogene au plutonium. (auteur)

  10. A computational model of pile vertical vibration in saturated soil based on the radial disturbed zone of pile driving

    International Nuclear Information System (INIS)

    Li Qiang; Shi Qian; Wang Kuihua

    2010-01-01

    In this study, a simplified computational model of pile vertical vibration was developed. The model was based on the inhomogeneous radial disturbed zone of soil in the vicinity of a pile disturbed by pile driving. The model contained two regions: the disturbed zone, which was located in the immediate vicinity of the pile, and the undisturbed region, external to the disturbed zone. In the model, excess pore pressure in the disturbed zone caused by pile driving was assumed to follow a logarithmic distribution. The relationships of stress and strain in the disturbed zone were based on the principle of effective stress under plain strain conditions. The external zone was governed by the poroelastic theory proposed by Biot. With the use of a variable separation method, an analytical solution in the frequency domain was obtained. Furthermore, a semi-analytical solution was attained by employing a numerical convolution method. Numerical results from the frequency and time domain indicated that the equivalent radius of the disturbed zone and the ratio of excess pore pressure had a significant effect on pile dynamic response. However, actual interactions between pile and soil will be weaker due to the presence of the radial disturbed zone, which is caused by pile driving. Consequently, the ideal undisturbed model overestimates the interaction between pile and soil; however, the proposed model reflects the interaction of pile and soil better than the perfect contact model. Numerical results indicate that the model can account for the time effect of pile dynamic tests.

  11. 3D FEM Analysis of a Pile-Supported Riverine Platform under Environmental Loads Incorporating Soil-Pile Interaction

    Directory of Open Access Journals (Sweden)

    Denise-Penelope N. Kontoni

    2018-01-01

    Full Text Available An existing riverine platform in Egypt, together with its pile group foundation, is analyzed under environmental loads using 3D FEM structural analysis software incorporating soil-pile interaction. The interaction between the transfer plate and the piles supporting the platform is investigated. Two connection conditions were studied assuming fixed or hinged connection between the piles and the reinforced concrete platform for the purpose of comparison of the structural behavior. The analysis showed that the fixed or hinged connection condition between the piles and the platform altered the values and distribution of displacements, normal force, bending moments, and shear forces along the length of each pile. The distribution of piles in the pile group affects the stress distribution on both the soil and platform. The piles were found to suffer from displacement failure rather than force failure. Moreover, the resulting bending stresses on the reinforced concrete plate in the case of a fixed connection between the piles and the platform were almost doubled and much higher than the allowable reinforced concrete stress and even exceeded the ultimate design strength and thus the environmental loads acting on a pile-supported riverine offshore platform may cause collapse if they are not properly considered in the structural analysis and design.

  12. Physics of phenomena in the zone close to an underground nuclear explosion; Physique des phenomenes en zone proche des explosions nucleaires souterraines

    Energy Technology Data Exchange (ETDEWEB)

    Maury, J; Levret, C [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    After a description of the phenomenology of underground explosions, the basic laws governing the propagation in the ground of the energy produced by the explosion are given. The reports considers hydrodynamics, the mechanics of solids, the equations of state for solids and gases in the case of very high and medium pressures, and the dynamical strength of solids. These various elements make it possible to draw up a system of equations which define completely the changes with time of the shock-wave produced in the ground by the explosion. (authors) [French] Apres une description de la phenomenologie des explosions souterraines, on expose les lois fondamentales regissant la propagation dans le sol de l'energie degagee par l'explosion. L'expose comprend des developpements sur l'hydrodynamique, la mecanique des solides, les equations d'etat des solides et des gaz, aux tres fortes et moyennes pressions, et sur la resistance dynamique des solides. Ces differents elements permettent d'ecrire un systeme d'equations qui definissent completement l'evolution dans le temps de l'onde de choc emise dans le sol par l'explosion. (auteurs)

  13. Physics of phenomena in the zone close to an underground nuclear explosion; Physique des phenomenes en zone proche des explosions nucleaires souterraines

    Energy Technology Data Exchange (ETDEWEB)

    Maury, J.; Levret, C. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    After a description of the phenomenology of underground explosions, the basic laws governing the propagation in the ground of the energy produced by the explosion are given. The reports considers hydrodynamics, the mechanics of solids, the equations of state for solids and gases in the case of very high and medium pressures, and the dynamical strength of solids. These various elements make it possible to draw up a system of equations which define completely the changes with time of the shock-wave produced in the ground by the explosion. (authors) [French] Apres une description de la phenomenologie des explosions souterraines, on expose les lois fondamentales regissant la propagation dans le sol de l'energie degagee par l'explosion. L'expose comprend des developpements sur l'hydrodynamique, la mecanique des solides, les equations d'etat des solides et des gaz, aux tres fortes et moyennes pressions, et sur la resistance dynamique des solides. Ces differents elements permettent d'ecrire un systeme d'equations qui definissent completement l'evolution dans le temps de l'onde de choc emise dans le sol par l'explosion. (auteurs)

  14. Etude du processus de changement vecu par des familles ayant decide d'adopter volontairement des comportements d'attenuation des changements climatiques

    Science.gov (United States)

    Leger, Michel T.

    Les activites humaines energivores telles l'utilisation intensive de l'automobile, la surconsommation de biens et l'usage excessif d'electricite contribuent aux changements climatiques et autres problemes environnementaux. Bien que plusieurs recherches rapportent que l'etre humain est de plus en plus conscient de ses impacts sur le climat de la planete, ces memes recherches indiquent qu'en general, les gens continuent a se comporter de facon non ecologique. Que ce soit a l'ecole ou dans la communaute, plusieurs chercheurs en education relative a l'environnement estiment qu'une personne bien intentionnee est capable d'adopter des comportements plus respectueux de l'environnement. Le but de cette these etait de comprendre le processus d'integration de comportements d'attenuation des changements climatiques dans des familles. A cette fin, nous nous sommes fixe deux objectifs : 1) decrire les competences et les procedes qui favorisent l'adoption de comportements d'attenuation des changements climatiques dans des familles et 2) decrire les facteurs et les dynamiques familiales qui facilitent et limitent l'adoption de comportements d'attenuation des changements climatiques dans des familles. Des familles ont ete invitees a essayer des comportements personnels et collectifs d'attenuation des changements climatiques de sorte a integrer des modes de vie plus ecologiques. Sur une periode de huit mois, nous avons suivi leur experience de changement afin de mieux comprendre comment se produit le processus de changement dans des familles qui decident volontairement d'adopter des comportements d'attenuation des changements climatiques. Apres leur avoir fourni quelques connaissances de base sur les changements climatiques, nous avons observe le vecu de changement des familles durant huit mois d'essais a l'aide de journaux reflexifs, d'entretiens d'explicitation et du journal du chercheur. La these comporte trois articles scientifiques. Dans le premier article, nous presentons une

  15. Investigation of the Dynamics Of NH{sup +}{sub 4} and H{sub 2}O Molecular Groups in Crystals; Etude de la Dynamique des Groupes Moleculaires NH{sup +}{sub 4} et H{sub 2}O dans les Cristaux; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 0414 0418 041d 0410 041c 0418 041a 0418 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 042b 0425 0413 0420 0423 041f 041f NH{sup +}{sub 4} H H{sub 2}O 0412 041a 0420 0418 0421 0422 0410 041b 041b 0410 0425 ; Estudio de la Dinamica de los Grupos Moleculares NH{sup +}{sub 4} Y H{sub 2}O en Cristales

    Energy Technology Data Exchange (ETDEWEB)

    Bajorek, A.; Machehina, T. A.; Parlin' Ski, K. [Ob' edinennyj Institut Jadernyh Issledovanij, Dubna, SSSR (Russian Federation)

    1965-06-15

    }){sub 2}Cr{sub 2}O{sub 7}, (NH{sub 4}){sub 2}CO{sub 3}) et de l'eau liee (BaCl{sub 2} * 2H{sub 2}O, SrCl{sub 2} * 6H{sub 2}O, CuSO{sub 4} * 5H{sub 2}O). Les travaux avaient pour objet d'etudier l'influence exercee par differents reseaux cristallins sur la dynamique des groupes mentionnes, et les liens existant entre les phenomenes de diffusion et les transitions de phase. Malgre les differences de structure des substances etudiees, on obtient a la temperature de l'azote liquide des spectres analogues; en regle generale, ils accusent deux pics: le premier est situe dans la region des transferts d'energie de 15 a 20 meV; le second dans celle de 35 a 70 meV, qui est associee aux oscillations de torsion des ions ammonium. L'intensite des pics depend de la structure des substances et diminue avec l'augmentation de la temperature de l'echantillon. On a constaute que, lors de certaines transitions de phase, l'intensite de la partie elastique du spectre se modifie brusquement (dans les cas de NH{sub 4}I, NH{sub 4}NO{sub 3} et (NH{sub 4}){sub 2}SO{sub 4}). Lorsque la temperature de NH{sub 4}Cl, NH{sub 4}Br et (NH{sub 4}){sub 2}(COO){sub 2} augmente, il apparait un pic supplementaire, deplace dans la direction des faibles energies par rapport aux pics de rotation differee. Les spectres des neutrons diffuses par des cristaux contenant de l'eau liee se ressemblent egalement. On y observe trois groupes de pics associes aux oscillations optiques et a la rotation differee des molecules d'eau. (author) [Spanish] En la memoria se presentan los resultados de las mediciones de la dispersion de neutrones termicos en cristales que contienen el ion amonio (NH{sub 4}CI, NH{sub 4}Br, NH{sub 4}I, NH{sub 4}F, NH{sub 4}NO{sub 3}, NH{sub 4}CNS, (NH{sub 4}){sub 2}SO{sub 4}, (NH{sub 4}){sub 2}S{sub 2}O{sub 8}, (NH{sub 4}){sub 2}Cr{sub 2}O{sub 7}, (NH{sub 4}){sub 2}CO{sub 3}) y agua de cristalizacion (BaCl{sub 2} * 2H{sub 2}O, SrCl{sub 2} * 6H{sub 2}O, CuSO{sub 4} * 5H{sub 2}O). La finalidad de las

  16. Are cometary nuclei primordial rubble piles?

    Science.gov (United States)

    Weissman, P. R.

    1986-01-01

    Whipple's icy conglomerate model for the cometary nucleus has had considerable sucess in explaining a variety of cometary phenomena such as gas production rates and nongravitational forces. However, as discussed here, both observational evidence and theoretical considerations suggest that the cometary nucleus may not be a well-consolidated single body, but may instead be a loosely bound agglomeration of smaller fragments, weakly bonded and subject to occasional or even frequent disruptive events. The proposed model is analogous to the 'rubble pile' model suggested for the larger main-belt asteroids, although the larger cometary fragments are expected to be primordial condensations rather than collisionally derived debris as in the asteroid case. The concept of cometary nuclei as primordial rubble piles is proposed as a modification of the basic Whipple model, not as a replacement for it.

  17. Some dynamic aspects of the thyroid function studied by a method of isotopic balance; Quelques aspects dynamiques de la fonction thyroidienne etudies par une methode d''equilibre isotopique'

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Claude

    1958-06-15

    This report addresses the use of a method which aims at directly measuring quantities of steady iodine involved by the thyroid metabolism in specific physiological conditions. The experiment is based on the use of male rats weighting 180 to 200 g which received an almost iodine-free diet. The daily dose of iodine is administered to each experimental group through beverage under the form of potassium iodide. After a delay, the usual beverage is replaced by a marked one. Iodine renewal by thyroid is monitored in vivo by external detection of radiations emitted by iodine 131. At the end of the experiment, rats are killed, and their blood is collected on heparin, centrifuged and processed to separate mineral iodine and hormonal iodine. Radioactivity is then measured with a scintillator and compared with that of a beverage sample [French] Le but de la methode utilisee est de mesurer directement les quantites d'iode stable mises en jeu par le metabolisme thyroidien dans des conditions physiologiques precises. Les travaux anterieurs ne permettent d'atteindre ces quantites que par des microdosages chimiques longs et delicats. En nous basant sur le principe du renouvellement d'un pool en etat dynamique stationnaire, nous decrivons une cinetique et mesurons en valeur absolue les differents parametres de ce systeme en equilibre.

  18. Concentration processes under tubesheet sludge piles in nuclear steam generators

    International Nuclear Information System (INIS)

    Gonzalez, F.; Spekkens, P.

    1987-01-01

    The process by which bulk water solutes are concentrated under tubesheet sludge piles in nuclear steam generators was investigated in the laboratory under simulated CANDU operating conditions. Concentration rates were found to depend on the tube heat flux and pile depth, although beyond a critical depth the concentration efficiency decreased. This efficiency could be expressed by a concentration coefficient, and was found to depend also on the sludge pile porosity. Solute concentration profiles in the sludge pile suggested that the concentration mechanism in a high-porosity/permeability pile is characterized by boiling mainly near or at the tube surface, while in low-porosity piles, the change of phase may also become important in the body of the sludge pile. In all cases, the full depth of the pile was active to some extent in the concentration process. As long as the heat transfer under the pile was continued, the solute remained under the pile and slowly migrated toward the bottom. When the heat transfer was stopped, the solute diffused back into the bulk solution at a rate slower than that of the concentration process

  19. Review of vibration effect during piling installation to adjacent structure

    Science.gov (United States)

    Rahman, Nurul Aishah Abd; Musir, Adhilla Ainun; Dahalan, Nurol Huda; Ghani, Abdul Naser Abdul; Khalil, Muhamad Kasimi Abd

    2017-12-01

    Basically, many major structures across the world such as towers, high rise building, houses and bridges utilize pile as a support material. The use of pile is important to strengthen the structures. However, this has led to another problem to the nearest surrounding structures resulted from pile driving. As part of a construction work, unavoidable pile driving activity generates a vibration towards the surrounding structures if uncontrolled may cause damage to the adjacent structure. As the current construction works are frequently located in urban areas where the distance between the nearest building structures is not far, vibration may cause damage to nearby structures. Knowing which part of the building that is mostly affected by various vibration patterns from the impact of pile driving is crucial. Thus, it is very important to predict the impact of vibration during piling installation work. This paper reviews the vibrations generated by piling activity toward surrounding structures in terms sources of vibration, impact of piling installation, pile-soil interaction, and factors affecting the vibration impact of building as well as to study the parameters involved in vibration generation during piling works.

  20. Interesting Developments in Testing Methods Applied to Foundation Piles

    Science.gov (United States)

    Sobala, Dariusz; Tkaczyński, Grzegorz

    2017-10-01

    Both: piling technologies and pile testing methods are a subject of current development. New technologies, providing larger diameters or using in-situ materials, are very demanding in terms of providing proper quality of execution of works. That concerns the material quality and continuity which define the integral strength of pile. On the other side we have the capacity of the ground around the pile and its ability to carry the loads transferred by shaft and pile base. Inhomogeneous nature of soils and a relatively small amount of tested piles imposes very good understanding of small amount of results. In some special cases the capacity test itself form an important cost in the piling contract. This work presents a brief description of selected testing methods and authors remarks based on cooperation with Universities constantly developing new ideas. Paper presents some experience based remarks on integrity testing by means of low energy impact (low strain) and introduces selected (Polish) developments in the field of closed-end pipe piles testing based on bi-directional loading, similar to Osterberg idea, but without sacrificial hydraulic jack. Such test is suitable especially when steel piles are used for temporary support in the rivers, where constructing of conventional testing appliance with anchor piles or kentledge meets technical problems. According to the author’s experience, such tests were not yet used on the building site but they bring a real potential especially, when the displacement control can be provided from the river bank using surveying techniques.

  1. Laterally Loaded Partially Prestressed Concrete Piles

    Science.gov (United States)

    1989-09-01

    of an extensive test program onl laterali y ioadeu. partially pr- estressed concrete fender piles. The study Included service load range as well ats...12,000-psi design strength). Configura- tion G utilized 14 r:- estress strand, in an unsymmetric pattern. To provide a uniform concrete prestress of 540...sudden loss in load carrying capacity directly related to the loss of concrete area. The compression concrete fractured longitudinally and along the

  2. CENTRIFUGAL VIBRATION TEST OF RC PILE FOUNDATION

    Science.gov (United States)

    Higuchi, Shunichi; Tsutsumiuchi, Takahiro; Otsuka, Rinna; Ito, Koji; Ejiri, Joji

    It is necessary that nonlinear responses of structures are clarified by soil-structure interaction analysis for the purpose of evaluating the seismic performances of underground structure or foundation structure. In this research, centrifuge shake table tests of reinforced concrete pile foundation installed in the liquefied ground were conducted. Then, finite element analyses for the tests were conducted to confirm an applicability of the analytical method by comparing the experimental results and analytical results.

  3. Horizontal vibrations of piles in a centrifuge

    International Nuclear Information System (INIS)

    Bourdin, B.

    1987-01-01

    The aim of the thesis is the study of soil dynamics for important structures like nuclear power plants, offshore platforms, dams etc. Experimental results of horizontal vibrations on a pile partially anchored in a soil scale model put into a centrifuge are presented. Mechanical similitude conditions from equilibrium equations or rheologic laws are described. After a description of testing equipment (centrifuge, electrodynamic excitator) experimental results are interpreted with a model. Non-linearities on frequency response curves are characterized [fr

  4. FORECASTING PILE SETTLEMENT ON CLAYSTONE USING NUMERICAL AND ANALYTICAL METHODS

    Directory of Open Access Journals (Sweden)

    Ponomarev Andrey Budimirovich

    2016-06-01

    Full Text Available In the article the problem of designing pile foundations on claystones is reviewed. The purpose of this paper is comparative analysis of the analytical and numerical methods for forecasting the settlement of piles on claystones. The following tasks were solved during the study: 1 The existing researches of pile settlement are analyzed; 2 The characteristics of experimental studies and the parameters for numerical modeling are presented, methods of field research of single piles’ operation are described; 3 Calculation of single pile settlement is performed using numerical methods in the software package Plaxis 2D and analytical method according to the requirements SP 24.13330.2011; 4 Experimental data is compared with the results of analytical and numerical calculations; 5 Basing on these results recommendations for forecasting pile settlement on claystone are presented. Much attention is paid to the calculation of pile settlement considering the impacted areas in ground space beside pile and the comparison with the results of field experiments. Basing on the obtained results, for the prediction of settlement of single pile on claystone the authors recommend using the analytical method considered in SP 24.13330.2011 with account for the impacted areas in ground space beside driven pile. In the case of forecasting the settlement of single pile on claystone by numerical methods in Plaxis 2D the authors recommend using the Hardening Soil model considering the impacted areas in ground space beside the driven pile. The analyses of the results and calculations are presented for examination and verification; therefore it is necessary to continue the research work of deep foundation at another experimental sites to improve the reliability of the calculation of pile foundation settlement. The work is of great interest for geotechnical engineers engaged in research, design and construction of pile foundations.

  5. Reheating experiment in the 35-ton pile

    International Nuclear Information System (INIS)

    Cherot, J.; Girard, Y.

    1957-01-01

    When the 35-ton pile was started up it was necessary for us, in order to study certain effects (xenon for example), to know the anti reactivity value of the rods as a function of their dimensions. We have made use of the possibility, in the reheating experiment, of raising the temperature of the graphite-uranium block by simple heating, in order to determine the anti reactivity curves of the rods, and from that the overall temperature coefficient. For the latter we have considered two solutions: first, one in which the average temperature of the pile is defined as our arithmetical mean of the different values given by the 28 thermocouples distributed throughout the pile; a second in which the temperature in likened to a poisoning and is balanced by the square of the flux. The way in which the measurements have been made is indicated, and the different instruments used are described. The method of reheating does not permit the separation of the temperature coefficients of uranium and of graphite. The precision obtained is only moderate, and suffers from the changes of various parameters necessary to other manipulations carried out simultaneously (life time modulators for example), and finally it is a function of the comparatively restricted time allowed. It is evident of course that more careful stabilisation at the different plateaux chosen would have necessitated long periods of reheating. (author) [fr

  6. Stability Limits for Rubble Pile Asteroid Shapes

    Science.gov (United States)

    Scheeres, Daniel

    2018-04-01

    The stability of rubble pile asteroids are explored analytically, using simple models for their constituent components. Specifically, we look at the stability of spherical components resting and potentially rolling on each other as a function of their relative sizes, configuration and number. This talk will present some recent results in this problem. Of specific interest is a 5:1 limit on the elongation of a rubble pile body for stability, which is interestingly the same extreme elongation found for the first interstellar object. This limit is for a rubble pile consisting of stacked spheres, resting on each other in a straight line. If there are 5 or less bodies resting on each other in this configuration, there is an interval of spin rates for which the configuration is stable. If there are 6 or more bodies stacked as such, the spin rate for it to stabilize is beyond the spin rate at which it fissions. The talk will also explore additional results for different configurations of bodies resting on each other.

  7. Geomorphic reclmation of a coal refuse pile

    Science.gov (United States)

    Hopkinson, L. C.; Quaranta, J.

    2017-12-01

    Geomorphic reclamation is a technique that may offer opportunities to improve mine reclamation in Central Appalachia. The design approach is based on constructing a steady-state, mature landform condition and takes into account the long-term climatic conditions, soil types, terrain grade, and vegetation. Geomorphic reclamation has been applied successfully in semi-arid regions but has not yet been applied in Central Appalachia. This work describes a demonstration study where geomorphic landforming techniques are being applied to a coarse coal refuse pile in southern West Virginia, USA. The reclamation design includes four geomorphic watersheds that radially drain runoff from the pile. Each watershed has one central draining channel and incorporates compound slope profiles similarly to naturally eroded slopes. Planar slopes were also included to maintain the impacted area. The intent is to alter the hydrology to decrease water quality treatment costs. The excavation cut and fill volumes are comparable to those of more conventional refuse pile reclamation designs. If proven successful then this technique can be part of a cost-effective solution to improve water quality at active and future refuse facilities, abandoned mine lands, bond forfeiture sites, landfills, and major earthmoving activities within the region.

  8. La pollution des sols des champs d’épandage d’eaux usées, contrainte et/ou ressource pour le développement durable en plaine de Bessancourt-Herblay-Pierrelaye

    Directory of Open Access Journals (Sweden)

    Vincent Mandinaud

    2005-11-01

    Full Text Available Historiquement affectés à l’assainissement des eaux usées brutes et à l’amendement des sols, les champs d’épandage de la ville de Paris, puis du SIAAP, sont au début de l’année 1997 en passe d’être publiquement reconnus pollués par des Eléments Traces Métalliques (ETM . Différentes opérations participent de ce double processus de reconsidération des risques associés à l’épandage et de requalification des entités territoriales concernées. La présentation dynamique des prises et des contraintes développées, en plaine de Bessancourt-Herblay-Pierrelaye singulièrement, permet de montrer comment la pollution des sols peut (réactiver localement une réflexion collective sur un développement territorial durable.

  9. Calculation of control rods in rectangular reactor, and applications (1960); Calcul des barres de conteole dans un reacteur rectangulaire et applications (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Goshen, S; Pazy, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The aim of this report is to find a method for estimating the anti-reactivity of control rods perpendicular to the axis in a cylindrical pile. The paper is divided into two parts. In the first is given a method of calculating control rods in a rectangular pile, similar to the Nordheim-Scalettar method for cylindrical piles. As an example the formulas are given for the theories of one and two neutron groups, the generalisation for several groups being evident. In the second part we find by a variation method a formula for estimating the Laplacian of a pile, which may be divided into parallelepipeds for which the Laplacian are given. Finally, this formula is used to calculate the anti-reactivity of rods perpendicular to the axis in a cylindrical pile. (author) [French] Le but de ce rapport est de trouver une methode pour estimer l'antireactivite des barres de controle perpendiculaires a l'axe dans pile cylindrique. Le rapport se divise en deux parties. Dans la premiere nous donnons une methode de calcul des barres de controle dans une pile rectangulaire, analogue a la methode de Nordheim-Scalettar pour les piles cylindriques. A titre d'exemple, nous donnons les formules de theories a un et deux groupes de neutrons, la generalisation pour plusieurs groupes est evidente. Dans la deuxieme partie, nous trouvons, par une methode de variation, une formule qui permet d'estimer le laplacien d'une pile, qui peut etre divisee en parallelepipedes dont les laplaciens sont donnes. Nous utilisons enfin, cette formule pour calculer l'antireactivite des barres perpendiculaires a l'axe dans une pile cylindrique. (auteur)

  10. Investigations in French battery and recycling plants; Traitement des dechets des piles et accumulateurs usages. Enquete dans des entreprises specialisees

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, A.; Elcabache, J.M. [Institut National de Recherche et de Securite -INRS, Lab. de Chimie Analytique Minerale, Dept. Metrologie des Polluants, Centre de Lorraine, 54 - Vandoeuvre (France)

    2003-07-01

    The Analytical Chemistry laboratory of INRS assessed the occupational exposure of 380 employees in 15 enterprises specialized in the reprocessing of electrochemical generators accepting to take part in this study (2 firms sorting and preparing batteries for shipment to reprocessing centres, 7 recycling plants for alkaline, nickel-cadmium and zinc-carbon batteries, 5 spent lead accumulator processing plants). Assessments were also carried out in an enterprise with a workforce of 180 producing 'mercury free' zinc-carbon batteries. These assessments highlighted: - a high potential risk of lead impregnation in the milling and fusion phases of spent lead accumulator processing; - a potential risk of mercury intoxication during the use of pyrometallurgical processes allowing other mercury waste products to be processed simultaneously to spent batteries; - that during the processing of nickel-cadmium batteries the air cleaning systems of the workshops are largely inefficient and must be improved. The constant wearing of filtering respirators is a solution that must remain temporary, the prevention measure to be applied as early as possible being the capture of the cadmium dust fume emissions at source. (authors)

  11. Response of shallow geothermal energy pile from laboratory model tests

    Science.gov (United States)

    Marto, A.; Amaludin, A.

    2015-09-01

    In shallow geothermal energy pile systems, the thermal loads from the pile, transferred and stored in the soil will cause thermally induced settlement. This factor must be considered in the geotechnical design process to avoid unexpected hazards. Series of laboratory model tests were carried out to study the behaviour of energy piles installed in kaolin soil, subjected to thermal loads and a combination of axial and thermal loads (henceforth known as thermo-axial loads). Six tests which included two thermal load tests (35°C and 40°C) and four thermo-axial load tests (100 N and 200 N, combined with 35°C and 40°C thermal loads) were conducted. To simulate the behaviour of geothermal energy piles during its operation, the thermo-axial tests were carried out by applying an axial load to the model pile head, and a subsequent application of thermal load. The model soil was compacted at 90% maximum dry density and had an undrained shear strength of 37 kPa, thus classified as having a firm soil consistency. The behaviour of model pile, having the ultimate load capacity of 460 N, was monitored using a linear variable displacement transducer, load cell and wire thermocouple, to measure the pile head settlement, applied axial load and model pile temperature. The acquired data from this study was used to define the thermo-axial response characteristics of the energy pile model. In this study, the limiting settlement was defined as 10% of the model pile diameter. For thermal load tests, higher thermal loads induced higher values of thermal settlement. At 40°C thermal load an irreversible settlement was observed after the heating and cooling cycle was applied to the model pile. Meanwhile, the pile response to thermo-axial loads were attributed to soil consistency and the magnitude of both the axial and thermal loads applied to the pile. The higher the thermoaxial loads, the higher the settlements occurred. A slight hazard on the model pile was detected, since the settlement

  12. Impedance function of a group of vertical piles

    International Nuclear Information System (INIS)

    Wolf, J.P.; Arx, G.A. von

    1978-01-01

    Impedance and transfer functions of a group of vertical piles located in any desired configuration in plan in a horizontally stratified soil layer are derived. Hysteretic and radiation damping are accounted for. The method separates the piles and the soil, introducing unknown interaction forces. The total flexibility matrix of the soil is constructed, superposing the (complex) flexibility coefficients caused by the interaction forces of a single pile only. The dependence of the impedance and transfer functions on the oscllating frequency for foundations with different numbers of piles is investigated. Pile-soil-pile interaction is shown to be very important for all modes of vibration. The procedure is used in the seismic analysis of a reactor building. (Author)

  13. Analytical out-of-pile and in-pile experiments on gadolinia bearing fuels

    International Nuclear Information System (INIS)

    Bruet, M.; Francois, B.; Do, Q.; Bergeron, J.; Trotabas, M.

    1986-06-01

    New fuel management schemes in PWRs can be achieved through the use of burnable poisons like gadolinia bearing fuel rods. However, the introduction of such a design has required a qualification program, which has been performed in collaboration between CEA, FRAGEMA and/or FRAMATOME by specialized teams in CEA facilities. The main scoops of this program concern: the fabrication process; the out of pile physical properties determination: the in pile thermomechanical behaviour and fission product release; the neutronic studies in view to validate the Computed Gd efficiency and the LBP depletion calculation schemes and to analyse and assess various schemes of core calculations

  14. Study of transient states in thermo-ionic converters; Etude des regimes transitoires des convertisseurs thermoioniques

    Energy Technology Data Exchange (ETDEWEB)

    Landrot, J [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    In order to control a thermo-ionic reactor, it is necessary to know the dynamic influence of four fundamental parameters: the injected thermal power, the electrical charge resistance, the temperature of the cesium and the thermal exchange coefficient of the collector cooling circuit. The principles of the thermo-ionic converter are briefly exposed. The over-riding influence of the first two parameters is shown with the help of experimental static readings. These two parameters are then made to vary in turn. The laws of variation as a function of the time, of the electrical power produced and of the temperature of the various parts of the converter are deduced. (author) [French] Pour envisager le controle et la regulation d'un reacteur thermoionique, il est necessaire de connaitre l'influence dynamique de quatre parametres fondamentaux: puissance thermique injectee, resistance electrique de charge, temperature de cesium et coefficient d'echange thermique du circuit de refroidissement du collecteur. On rappelle brievement les principes du convertisseur thermoionique. A l'aide de releves statiques experimentaux, on montre l'influence preponderante des deux premiers parametres. On fait ensuite varier successivement ces deux parametres. On met en evidence les lois de variation en fonction du temps de la puissance electrique produite et de la temperature des differents points du convertisseur. (auteur)

  15. Study of transient states in thermo-ionic converters; Etude des regimes transitoires des convertisseurs thermoioniques

    Energy Technology Data Exchange (ETDEWEB)

    Landrot, J. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    In order to control a thermo-ionic reactor, it is necessary to know the dynamic influence of four fundamental parameters: the injected thermal power, the electrical charge resistance, the temperature of the cesium and the thermal exchange coefficient of the collector cooling circuit. The principles of the thermo-ionic converter are briefly exposed. The over-riding influence of the first two parameters is shown with the help of experimental static readings. These two parameters are then made to vary in turn. The laws of variation as a function of the time, of the electrical power produced and of the temperature of the various parts of the converter are deduced. (author) [French] Pour envisager le controle et la regulation d'un reacteur thermoionique, il est necessaire de connaitre l'influence dynamique de quatre parametres fondamentaux: puissance thermique injectee, resistance electrique de charge, temperature de cesium et coefficient d'echange thermique du circuit de refroidissement du collecteur. On rappelle brievement les principes du convertisseur thermoionique. A l'aide de releves statiques experimentaux, on montre l'influence preponderante des deux premiers parametres. On fait ensuite varier successivement ces deux parametres. On met en evidence les lois de variation en fonction du temps de la puissance electrique produite et de la temperature des differents points du convertisseur. (auteur)

  16. Methodes de calcul des forces aerodynamiques pour les etudes des interactions aeroservoelastiques

    Science.gov (United States)

    Biskri, Djallel Eddine

    L'aeroservoelasticite est un domaine ou interagissent la structure flexible d'un avion, l'aerodynamique et la commande de vol. De son cote, la commande du vol considere l'avion comme une structure rigide et etudie l'influence du systeme de commande sur la dynamique de vol. Dans cette these, nous avons code trois nouvelles methodes d'approximation de forces aerodynamiques: Moindres carres corriges, Etat minimal corrige et Etats combines. Dans les deux premieres methodes, les erreurs d'approximation entre les forces aerodynamiques approximees par les methodes classiques et celles obtenues par les nouvelles methodes ont les memes formes analytiques que celles des forces aerodynamiques calculees par LS ou MS. Quant a la troisieme methode, celle-ci combine les formulations des forces approximees avec les methodes standards LS et MS. Les vitesses et frequences de battement et les temps d'executions calcules par les nouvelles methodes versus ceux calcules par les methodes classiques ont ete analyses.

  17. Assessment of Time Functions for Piles Driven in Clay

    DEFF Research Database (Denmark)

    Augustesen, Anders; Andersen, Lars; Sørensen, Carsten Steen

    The vertical bearing capacity of piles situated in clay is studied with regard to the long-term set-up. A statistical analysis is carried out on the basis of data from numerous static loading tests. The database covers a wide range of both soil and pile properties, which ensures a general....... Hence, it is suggested that a constant set-up factor should be applied for the prediction of pile capacities at a given time after initial driving....

  18. Sécurité et ordre politique au Cameroun : entre dynamiques ...

    African Journals Online (AJOL)

    chifaou.amzat

    présidentielle de la sécurité publique et une fabrication politique de l'insécurité ...... L'insécurité participe d'une stratégie globale de soumission des masses. La différenciation qui ... des entreprises privées étrangères de sécurité telles que Wackenhut et ... parti au pouvoir et des lieux de recrutement du personnel politique.

  19. Characteristics of thermal neutron calibration fields using a graphite pile

    International Nuclear Information System (INIS)

    Uchita, Yoshiaki; Saegusa, Jun; Kajimoto, Yoichi; Tanimura, Yoshihiko; Shimizu, Shigeru; Yoshizawa, Michio

    2005-03-01

    The Facility of Radiation Standards of Japan Atomic Energy Research Institute is equipped with thermal neutron fields for calibrating area and personal neutron dosemeters. The fields use moderated neutrons leaked from a graphite pile in which radionuclide sources are placed. In January 2003, we have renewed the pile with some modifications in its size. In accordance with the renewal, we measured and calculated thermal neutron fluence rates, neutron energy distributions and angular distributions of the fields. The thermal neutron fluence rates of the ''inside-pile fields'' and the outside-pile fields'' were determined by the gold foil activation method. The neutron energy distributions of the outside-pile fields were also measured with the Bonner multi-sphere spectrometer system. The contributions of epithermal and fast neutrons to the total dose-equivalents were 9% in the southern outside-pile field and 12% in the western outside-pile field. The personal dose-equivalents, H p,slab (10, α), in the outside-pile fields are evaluated by considering the calculated angular distributions of incoming neutrons. The H p,slab (10, α) was found to be about 40% higher than the value in assuming the unidirectional neutron between the pile and the test point. (author)

  20. Nanoindentation-induced pile-up in hydrogenated amorphous silicon

    International Nuclear Information System (INIS)

    Pantchev, B; Danesh, P; Wiezorek, J; Schmidt, B

    2010-01-01

    Nanoindentation-induced material extrusion around the nanoindent (pile-up) leads to an overestimation of elastic modulus, E, and nanohardness, H, when the test results are evaluated using the Oliver and Pharr method. Factors affecting the pile-up during testing are residual stresses in film and ratio of film and substrate mechanical properties. Nanoindentation of hydrogenated amorphous silicon (a-Si:H) films has been carried out with the aim to study the effect of residual compressive stress on the pile-up in this material. To distinguish the contribution of compressive stress to the appearance of pile-up ion implantation has been used as a tool, which reduces the compressive stress in a-Si:H. Scanning probe microscope has been used for the imaging of the indent and evaluation of the pile-up. The values of E and H have been obtained from the experimental load-displacement curves using depth profiling with Berkovich tip, which has created negligible pile-up. A sharper cube corner tip has been used to study the pile-up. It has been established that pile-up is determined by the material plasticity, when the compressive stress is below 200 MPa. The contribution of mechanical stress to the pile-up is essential for the stress as high, as about 500 MPa.

  1. Analysis of transients in the SRP test pile

    International Nuclear Information System (INIS)

    Church, J.P.

    1976-11-01

    Analysis of the hypothetical upper limit accident in the Savannah River Test Pile showed that the offsite thyroid dose from fission product release would be -3 of the 10-CFR-100 guideline dose for 95 percent of measured meteorological conditions. Offsite whole body dose would be negligible. The Test Pile was modified to limit the length of test piece that can be charged to the pile. These modifications reduce the potential offsite dose to -5 of the regulatory guidelines. Assessment of Test Pile safety included calculations of transients initiated by a variety of reactivity additions that were either terminated or not terminated by safety systems. Reactivity addition mechanisms considered were abnormally driving control rods out of the pile and charging abnormal test pieces into the pile. The transients were evaluated in the adiabatic approximation in which three-dimensional calculations of static flux shapes and reactivity were superimposed on point reactor kinetics calculations. Negative reactivity feedback effects appropriate for the pile and the temperature dependence of material properties, such as specific heat and thermal conductivity, were included. The results show that, for the worst initiators, safety systems can prevent the temperature rise from exceeding 1 0 C anywhere in the Test Pile. If the safety systems do not function, the pile temperatures will increase until the transient is ended by the inherent negative reactivity effects, including the melting of some fuel

  2. Critical sizes and flux distributions in the shut down pile

    International Nuclear Information System (INIS)

    Banchereau, A.; Berthier, P.; Genthon, J.P.; Gourdon, C.; Lattes, R.; Martelly, J.; Mazancourt, R. de; Portes, L.; Sagot, M.; Schmitt, A.P.; Tanguy, P.; Teste du Bailler, A.; Veyssiere, A.

    1957-01-01

    An important part of the experiments carried out on the reactor G1 during a period of shut-down has consisted in determinations of critical sizes, and measurements of flux distribution by irradiations of detectors. This report deals with the following points: 1- Critical sizes of the flat pile, the long pile and the uranium-thorium pile. 2- Flux charts of the same piles, and study of an exponential experiment. 3- Determination of the slit effect. 4- Calculation of the anisotropy of the lattice. 5- Description of the experimental apparatus of the irradiation measurements. (author) [fr

  3. Foundation heat transfer analysis for buildings with thermal piles

    International Nuclear Information System (INIS)

    Almanza Huerta, Luis Enrique; Krarti, Moncef

    2015-01-01

    Highlights: • A numerical transient thermal model for thermo-active foundations is developed. • Thermal interactions between thermal piles and building foundations are evaluated. • A simplified analysis method of thermal interactions between thermal piles and building foundations is developed. - Abstract: Thermal piles or thermo-active foundations utilize heat exchangers embedded within foundation footings to heat and/or cool buildings. In this paper, the impact of thermal piles on building foundation heat transfer is investigated. In particular, a simplified analysis method is developed to estimate the annual ground-coupled foundation heat transfer when buildings are equipped with thermal piles. First, a numerical analysis of the thermal performance of thermo-active building foundations is developed and used to assess the interactions between thermal piles and slab-on-grade building foundations. The impact of various design parameters and operating conditions is evaluated including foundation pile depth, building slab width, foundation insulation configuration, and soil thermal properties. Based on the results of a series of parametric analyses, a simplified analysis method is presented to assess the impact of the thermal piles on the annual heat fluxes toward or from the building foundations. A comparative evaluation of the predictions of the simplified analysis method and those obtained from the detailed numerical analysis indicated good agreement with prediction accuracy lower than 5%. Moreover, it is found that thermal piles can affect annual building foundation heat loss/gain by up to 30% depending on foundation size and insulation level

  4. Reducing Local Scouring at Bridge Piles Using Collars and Geobags

    Directory of Open Access Journals (Sweden)

    Shatirah Akib

    2014-01-01

    Full Text Available The present study examines the use of collars and geobags for reducing local scour around bridge piles. The efficiency of collars and geobags was studied experimentally. The data from the experiments were compared with data from earlier studies on the use of single piles with a collar and with a geobag. The results showed that using a combination of a steel collar and a geobag yields the most significant scour reduction for the front and rear piles, respectively. Moreover, the independent steel collar showed better efficiency than the independent geobag below the sediment level around the bridge piles.

  5. Des broussailles dans les prairies alpines

    Directory of Open Access Journals (Sweden)

    Olivier Camacho

    2009-03-01

    expliquer pourquoi l'embroussaillement gagne des prairies encore exploitées. Si la fauche permet de lutter efficacement contre l’avancée des ligneux, il n’en est pas de même dans les prairies pâturées non fauchées où la capacité de prélèvement par les troupeaux s’avère faible par rapport à la production d’herbe. Cette situation se répète d’année en année et c’est la cause la plus probable de la propagation des ligneux. Pour sécuriser leur système fourrager et pour simplifier le travail, les éleveurs constituent des unités de pâturage surdimensionnées par rapport aux besoins des animaux. Ils mettent en œuvre des pratiques de rattrapage, consistant en un entretien mécanique complémentaire au pâturage, pour contenir la dynamique des ligneux. De telles pratiques, exigeantes en travail, ne sont pas mises en œuvre sur toutes les pâtures. L’analyse des pratiques par des agronomes complète ainsi les études de milieux physiques et socio-économiques tant au niveau de la parcelle pâturée qu’à celui de la vallée.

  6. Static and dynamic efficiency of white certificate schemes; L'efficacite statique et dynamique des dispositifs de -certificats blancs-

    Energy Technology Data Exchange (ETDEWEB)

    Giraudet, L.G. [CIRED-ENPC, 94 - Nogent-sur-Marne (France); Finon, D. [CIRED-CNRS, 94 - Nogent-sur-Marne (France)

    2011-07-15

    White Certificate Schemes mandate energy companies to promote energy efficiency through flexibility mechanisms, including the trading of energy savings. They can be characterized as a quantity-based, baseline-and-credit system for the diffusion of energy efficient technologies. This paper compares experiences with White Certificate Schemes in Great Britain, Italy and France, in order to identify the basic drivers of each, and ultimately offer an original interpretation as an adaptive instrument, in the sense that it can take different forms in response to specific institutional contexts. A first analysis shows that Schemes perform well in terms of static efficiency, i.e. they are cost-effective and generate net social benefits over the period considered, though with large discrepancies rooted in different technological potentials. Regarding dynamic efficiency, i.e. the ability to induce and sustain technological change over the long haul, market transformation occurred in Great Britain, but was poorly incentivized in Italy and France by inadequate compliance cost recovery rules. Substantial organizational change has occurred in every country, mainly by strengthening vertical relationships between obliged parties and upstream businesses. Overall, the obligation (rather than the market component) drives the early phases of the Schemes. (authors)

  7. Impacts des vers de terre sur les composants et la dynamique du sol (synthèse bibliographique)

    OpenAIRE

    Lemtiri, A.; Colinet, G.; Alabi, T.; Cluzeau, D.; Zirbes, L.; Haubruge, E.; Francis, F.

    2014-01-01

    Impacts of earthworms on soil components and dynamics. A review. Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil fertility by participating to important processes in soil such as soil structure regulation and organic matter dynamics. Earthworms also modify the microbial communities through digestion, stimulation and dispersion in casts. Conseque...

  8. Impacts des vers de terre sur les composants et la dynamique du sol (synthèse bibliographique

    Directory of Open Access Journals (Sweden)

    Lemtiri, A.

    2014-01-01

    Full Text Available Impacts of earthworms on soil components and dynamics. A review. Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil fertility by participating to important processes in soil such as soil structure regulation and organic matter dynamics. Earthworms also modify the microbial communities through digestion, stimulation and dispersion in casts. Consequently, changes in the activities of earthworm communities, as a result of soil management practices, can also be used as indicators of soil fertility and quality. It is therefore important to understand how earthworm communities affect soil dynamics. This review adresses the current state of knowledge on earthworm's impacts on soil structure and soil organic matter (carbon, nitrogen, and phosphorus dynamics, with special emphasis on the effects of land management practices on earthworm communities.

  9. Integration of dynamical data in a geostatistical model of reservoir; Integration des donnees dynamiques dans un modele geostatistique de reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Costa Reis, L.

    2001-01-01

    We have developed in this thesis a methodology of integrated characterization of heterogeneous reservoirs, from geologic modeling to history matching. This methodology is applied to the reservoir PBR, situated in Campos Basin, offshore Brazil, which has been producing since June 1979. This work is an extension of two other thesis concerning geologic and geostatistical modeling of the reservoir PBR from well data and seismic information. We extended the geostatistical litho-type model to the whole reservoir by using a particular approach of the non-stationary truncated Gaussian simulation method. This approach facilitated the application of the gradual deformation method to history matching. The main stages of the methodology for dynamic data integration in a geostatistical reservoir model are presented. We constructed a reservoir model and the initial difficulties in the history matching led us to modify some choices in the geological, geostatistical and flow models. These difficulties show the importance of dynamic data integration in reservoir modeling. The petrophysical property assignment within the litho-types was done by using well test data. We used an inversion procedure to evaluate the petrophysical parameters of the litho-types. The up-scaling is a necessary stage to reduce the flow simulation time. We compared several up-scaling methods and we show that the passage from the fine geostatistical model to the coarse flow model should be done very carefully. The choice of the fitting parameter depends on the objective of the study. In the case of the reservoir PBR, where water is injected in order to improve the oil recovery, the water rate of the producing wells is directly related to the reservoir heterogeneity. Thus, the water rate was chosen as the fitting parameter. We obtained significant improvements in the history matching of the reservoir PBR. First, by using a method we have proposed, called patchwork. This method allows us to built a coherent model from various parts of a set of models. Then, starting with the model obtained by patchwork, we used the regionalized gradual deformation method for further improve the history matching. (author)

  10. La dynamique d'ajustement des taux de change réels dans la zone franc CFA

    OpenAIRE

    Cécile Couharde; Issiaka Coulibaly; Olivier Damette

    2012-01-01

    The aim of this paper is to analyse the adjustment process of real effective exchange rates towards their equilibrium level for the cfa zone countries over the period 1985-2007. Accordingly, we estimate a panel smooth transition error correction model in order to take into account non-linear phenomena. In particular, we show that the adjustment process of real effective exchange rates is indeed asymmetric while this asymmetry differs substantially between countries. This last result tends to ...

  11. Contribution of dynamic focusing to ultrasonic defect characterization; Contribution de la focalisation dynamique a la caracterisation ultrasonore des defauts

    Energy Technology Data Exchange (ETDEWEB)

    Mahaut, S. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes et Systemes Avances]|[Paris-7 Univ., 75 (France)

    1997-12-31

    Non destructive testing of vessels of pressurized water reactors uses ultrasonic focused transducers, with spherically shaped emitting surface or requiring an acoustic lens. But a mechanically focused transducer has to be used for a given inspection zone and for a fixed control configuration. The aim of this thesis is to improve ultrasonic defect characterization using adaptive dynamic focusing. Such a technique makes use of a ultrasonic defect characterization using adaptive dynamic focusing. Such a technique makes use of an ultrasonic transducer split into an array of individually controlled elements, allowing to apply delay and amplitude laws, calculated from modeling or experimentally deduced. Acoustical characteristics of the ultrasonic beam in the inspected specimen this can be electronically controlled; refraction angle, depth focusing, beam width. We briefly describe in the first chapter a theoretical modeling of the ultrasonic field radiated through a fluid/solid interface, extended to phase array transducers. This model is based on the integral formulation of Rayleigh, modified to take into account transmission through a fluid/solid (homogeneous and isotropic), of planar or cylindrical shape. In the second chapter an experimental study of this technique, with delay and amplitude laws given from the model, is presented, showing the efficiency of this method to adjust the acoustic performances. In he third chapter, experimental delay laws, extracted from the time distribution of signals received by the array (issued from a preliminary detected reflector), are used to provide an optimal imaging of the defect. This self-focusing procedure shows to adapt to a defect without using theoretical delays. The last chapter is dedicated to different applications devoted to improved defect characterization. The first application uses amplitude distribution received by the array, pointing out geometric characteristics of the reflector, while the second application, using different inspection angles, enables to discriminate volumic or planar defects. (author)

  12. A dynamical management for the handling of alarms at CERN; Une supervision dynamique pour la gestion des alarmes au CERN

    Energy Technology Data Exchange (ETDEWEB)

    Parisot, F

    2007-06-15

    The LHC (large hadron collider) is a huge 27 km long particle accelerator that is being installed 100 meter deep underground near Geneva. This machine requires a sophisticated and complex safety system in charge of the security of staff, infrastructure and equipment. The main features of this system is to be completely redundant by itself and be flexible enough to incorporate new parameters from modification of the accelerating system or from new equipment. The redundancy has been thoroughly studied, for instance a cable can be made of copper threads while the other is an optic fiber which add more safety by being able to cope better with the diversity of accidental situations. The LHC site has been divided into 33 security areas and 4 levels of emergency have been set: level 0 is the conveyance of pure information, level 1 is the conveyance of more important information that requires the intervention of an operator within the day, level 2 requires the intervention of an operator immediately, and level 3 is the emergency level for the intervention of the fire brigade. This safety system is in charge of 300000 parameters from a large variety of sensors and manages 17000 alarms. (A.C.)

  13. Statistical fluctuations in reactors (1960); Fluctuations statistiques dans les piles (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The theory of space dependent fluctuations is developed, taking into account the effect of delayed neutrons. The 'diffusion equation' or Fokker-Planck equation is worked out in the case of age and two group theory, but the first one because of in physical significance is used in this report. The theory is applied to the study of the spectral density of fluctuations and fluctuations of counting rate and current flowing through the charge resistor of an ionisation chamber, the effect of the entrance capacity is discussed. The space dependent theory shows that the fluctuations in the core and reflector of a near critical pile obey to the same law. The spectral densities in the core and reflector are similar, there is no sensible attenuation of high frequency fluctuations in the reflector. Compared to the space independent theory, this theory give better agreement with experience, one can use the simple space independent theory but in checking with experiment it is necessary to introduce numerical factors given by the space dependent theory. (author) [French] La theorie des fluctuations statistiques est developpee dans le cas spatial en tenant compte des neutrons retardes, et dans le cadre de la theorie de l'age vitesse. L'equation d'evolution de la probabilite est egalement etablie dans le cadre de la theorie a deux groupes. Ces considerations sont appliquees a l'etude de la densite spectrale des fluctuations et aux fluctuations des taux de comptage et du courant circulant dans la resistance de charge du detecteur. On etudie en particulier l'effet de la constante de temps introduite par la capacite d'entree. Cette theorie etablit que les fluctuations dans le coeur et le reflecteur suivent la meme loi pour une pile critique, il en est de meme pour la densite spectrale meme a frequence elevee. Par rapport a la theorie d'ensemble, la theorie spatiale donne des coefficients numeriques ou facteurs de forme, qui permettent d'obtenir un bon accord entre la theorie et l

  14. Natural radioactivity at CBPP waste pile

    International Nuclear Information System (INIS)

    Kovac, Jadranka; Marovic, Gordana

    2008-01-01

    Electrical power requirements will necessitate doubling the present generating capacity in Croatia in the future. As a result, environmental discharges associated with the coal power industry will considerably increase. Burning of coal is one source of enhanced radiation exposure to naturally occurring elements, particularly members of uranium and thorium decay chains. By coal burning (in CBPP at about 1700 C degrees) the activity originating from uranium and thorium is redistributed from underground (where the impact on humanity is nil) and liberated into the environment. Most of the radioactive substances are concentrated in the ash and slag, which are heavy and drop to the bottom of a furnace, lately transported to deposit pile, from where some activity may leach into aquifer, or be dispersed by wind. Lighter fly ash, however, is carried up the chimney and into the atmosphere and irradiates people and contaminates food crops. Also, 222 Rn escapes into the atmosphere during incineration, while the non-gaseous members of the uranium decay series remain in the ash and slag. Extensive investigations have been performed in the coal burning power plant (CBPP) Plomin in Croatia and at deposit pile. A network of radon escalation measurements, in-situ gamma-spectrometric measurements and monitoring of waste pile were organized. The results of the measurements confirm that the ash/slag deposite site are well monitored and involve all the necessary protective measures. All obtained data can be used as a valuable database for future estimations and modeling of the impact of radioactive pollution to the marine environment. (author)

  15. Occupational PAH Exposures during Prescribed Pile Burns

    Science.gov (United States)

    Robinson, M. S.; Anthony, T. R.; Littau, S. R.; Herckes, P.; Nelson, X.; Poplin, G. S.; Burgess, J. L.

    2008-01-01

    Wildland firefighters are exposed to particulate matter and gases containing polycyclic aromatic hydrocarbons (PAHs), many of which are known carcinogens. Our objective was to evaluate the extent of firefighter exposure to particulate and PAHs during prescribed pile burns of mainly ponderosa pine slash and determine whether these exposures were correlated with changes in urinary 1-hydroxypyrene (1-HP), a PAH metabolite. Personal and area sampling for particulate and PAH exposures were conducted on the White Mountain Apache Tribe reservation, working with 21 Bureau of Indian Affairs/Fort Apache Agency wildland firefighters during the fall of 2006. Urine samples were collected pre- and post-exposure and pulmonary function was measured. Personal PAH exposures were detectable for only 3 of 16 PAHs analyzed: naphthalene, phenanthrene, and fluorene, all of which were identified only in vapor-phase samples. Condensed-phase PAHs were detected in PM2.5 area samples (20 of 21 PAHs analyzed were detected, all but naphthalene) at concentrations below 1 μg m−3. The total PAH/PM2.5 mass fractions were roughly a factor of two higher during smoldering (1.06 ± 0.15) than ignition (0.55 ± 0.04 μg mg−1). There were no significant changes in urinary 1-HP or pulmonary function following exposure to pile burning. In summary, PAH exposures were low in pile burns, and urinary testing for a PAH metabolite failed to show a significant difference between baseline and post-exposure measurements. PMID:18515848

  16. Identification d’une nouvelle molécule d’intérêt chez le cheval atteint d’obstruction récurrente des voies respiratoires: La Pentraxine 3

    OpenAIRE

    Ramery, Eve

    2010-01-01

    L’ORVR ou obstruction récurrente des voies respiratoires (ORVR) est la cause la plus fréquente de maladie pulmonaire chronique chez le cheval adulte. La maladie se caractérise par une hyperréactivité bronchique, une production excessive de mucus et une inflammation neutrophilique pulmonaire qui ont pour effet de réduire la compliance dynamique du poumon et d’augmenter la résistance des voies respiratoires au débit aérien. Alors que la maladie est une entité documentée dans la littérature depu...

  17. Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles

    Directory of Open Access Journals (Sweden)

    Wang Duanduan

    2015-01-01

    Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.

  18. Prediction of pile set-up for Ohio soils : executive summary report.

    Science.gov (United States)

    2011-02-01

    ODOT typically uses small diameter driven pipe piles for bridge foundations. When a pile is driven into the subsurface, it disturbs and displaces the soil. As the soil surrounding the pile recovers from the installation disturbance, a time dependant ...

  19. INFLUENCE OF A ROUND CAP ON THE BEARING CAPACITY OF A LATERALLY LOADED PILE

    Directory of Open Access Journals (Sweden)

    Buslov Anatoliy Semenovich

    2012-07-01

    The data has proven that cap-covered piles are substantially more economical (over 40 % in terms of materials consumption rate if compared to constant cross-section piles (cap-free or broadening piles, all other factors being equal.

  20. Engineering approach to modeling of piled systems

    International Nuclear Information System (INIS)

    Coombs, R.F.; Silva, M.A.G. da

    1980-01-01

    Available methods of analysis of piled systems subjected to dynamic excitation invade areas of mathematics usually beyond the reach of a practising engineer. A simple technique that avoids that conflict is proposed, at least for preliminary studies, and its application, compared with other methods, is shown to be satisfactory. A corrective factor for parameters currently used to represent transmitting boundaries is derived for a finite strip that models an infinite layer. The influence of internal damping on the dynamic stiffness of the layer and on radiation damping is analysed. (Author) [pt

  1. Visual in-pile fuel disruption experiments

    International Nuclear Information System (INIS)

    Cano, G.L.; Ostensen, R.W.; Young, M.F.

    1978-01-01

    In a loss-of-flow (LOF) accident in an LMFBR, the mode of disruption of fuel may determine the probability of a subsequent energetic excursion. To investigate these phenomena, in-pile disruption of fission-heated irradiated fuel pellets was recorded by high speed cinematography. Instead of fuel frothing or dust-cloud breakup (as used in the SAS code) massive and very rapid fuel swelling, not predicted by analytical models, occurred. These tests support massive fuel swelling as the initial mode of fuel disruption in a LOF accident. (author)

  2. Installation effects of auger cast-in-place piles

    Directory of Open Access Journals (Sweden)

    Fathi M. Abdrabbo

    2012-12-01

    Full Text Available Since their introduction in Europe and North America some 50 years ago, auger cast-in-place piles (ACIP have become increasingly popular all over the world. These piles offer considerable environmental advantages during construction including minimal vibration, and low noise beside their high productivity. The most severe limitation of the ACIP is its sensitivity to operator performance, which can lead to a pile of poor integrity or inconsistent quality. Thus the improper use of ACIP equipment can result in piles containing defects or can cause instability of nearby structures. Three case studies are presented and discussed in an effort to illustrate learned lessons. First case study highlights the misuse of ACIP equipment leading to unreliable defective pile foundations. Second and third case studies show the adverse effects of installing ACIP on the stability of nearby structures. The study revealed that it is essential to employ a clever pile crew during the installation of ACIP to observe, interpret, and take corrective actions for unusual situations. The authorities worldwide should oblige pile contractors to employ only experienced and qualified workers in charge of geotechnical engineering works. Tender documents should include precise clauses related to the technological factors affecting the quality of ACIP. Unfavorable side effects of installing ACIP in saturated loose and medium sand can cause tilt of adjacent existing structures; even they are on either shallow or deep foundations. A row of micro-piles and/or soil grouting adjacent to the existing buildings were successfully used to reduce the adverse effects of ACIP. Implementation of different codes on the results of pile loading tests produced different pile working loads. Therefore tender documents should specify the code upon which interpreting the pile test results. At the meantime the geotechnical engineer should implement his experience and judgment during application of the

  3. Application of solar chargers to prospection instruments; Application des chargeurs solaires aux appareils de prospection

    Energy Technology Data Exchange (ETDEWEB)

    Caille, G [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The use of conventional batteries has certain disadvantages, and for this reason high-voltage batteries have been gradually replaced in all prospection instruments by transistor supply systems, using less cumbersome sources of energy. All the same low voltages are still necessary, and in hot or damp countries the use of these batteries leads to consumptions out of all proportion to the services rendered. This is why the use of solar energy possesses real advantages. After a brief review of the basic ideas on semiconductors, this article describes a selenium solar battery which was developed by the Westinghouse brakes and signals society. (author) [French] L'utilisation de piles classiques presente certains inconvenients. C'est pourquoi, dans tous les appareils de prospection, les piles fournissant des tensions elevees ont ete remplacees au fur et a mesure par des alimentations a base de transistors, utilisant des sources d'energie moins encombrantes. Toutefois, il faut tout de meme avoir des tensions faibles et l'utilisation de ces piles entraine dans les pays chauds ou humides une consommation disproportionnee par rapport aux services rendus. C'est pourquoi l'emploi de l'energie solaire presente de reels avantages. Cet expose decrit, apres un rappel de notion de base sur les semi-conducteurs, une batterie solaire a base de selenium qui a ete realisee par la Societe des freins et signaux Westinghouse. (auteur)

  4. Heave induced reduction of friction capacity of pile embedded in clays

    OpenAIRE

    Setyo Budi Gogot; Wibowo Tantri Gondo

    2017-01-01

    Installation of new piles may cause heave which influence friction capacity of existing piles. The heave can be observed from the difference in the elevation of existing pile heads recorded before and after the installation of new piles or through load-settlement diagram from Static Load Test data. This paper presents the study of bearing capacity of hollow cylindrical concrete piles with diameter of 800 mm from two projects. The piles at Project I and Project II were hydraulically jacked int...

  5. Mécanismes d'écoulement des charges à la surface des polymères granulaires

    Directory of Open Access Journals (Sweden)

    M. Kachi

    2014-09-01

    Full Text Available Les forces électriques s’exerçant sur des polymères granulaires chargés sont mises à profit dans plusieurs processus électrostatiques. La dynamique de charges de surface de ces matériaux est très importante pour ce type de processus. Le but de ce papier est d’analyser l’écoulement des charges à la surface de couches compactes de polymères granulaires, en interprétant les mesures sans contact réalisées par trois sondes de potentiel, de champ et de charge, ayant chacune une taille différente. Des mesures du profile de potentiel à différents instants sont également réalisées afin d’expliquer les différences entre les vitesses de déclin de potentiel, de champ et de charge mesurées par les trois sondes. Les résultats mettent en évidence un écoulement transversal et longitudinal de la charge surfacique.

  6. La nouvelle donne de la santé globale : dynamiques et écueils

    Directory of Open Access Journals (Sweden)

    Marine Buissonnière

    2012-04-01

    Full Text Available Les quinze dernières années ont été marquées par l’avènement de nouveaux acteurs dans le champ de la santé globale et l’augmentation de l’aide au développement en faveur de la santé. Ces acteurs ont capté une partie importante des ressources privées et publiques supplémentaires disponibles et se sont imposés comme les pièces maîtresses de ce nouvel échiquier, aux dépens des institutions traditionnelles qui ont graduellement perdu leur prépondérance et ont vu leur leadership s’affaiblir. Les choix et politiques de santé ont peu à peu échappé à la seule autorité des institutions qui en avaient jusqu’alors le mandat et en assumaient la charge. Certains pans entiers de la santé sont désormais dominés par des financeurs privés, devenus de facto prescripteurs d’orientations de santé publique. Cette nouvelle donne pose des questions essentielles de gouvernance et de responsabilité. Qui décide des orientations ? Comment les décisions sont-elles prises ? Les pays destinataires de l’aide doivent encore trop souvent subir le manque de coordination des donateurs et l’absence d’alignement des agendas. Dans ce contexte, et en prenant acte de cette nouvelle réalité, quelques pistes mériteraient d’être explorées afin de garantir que les orientations en matière de santé globale reflètent au mieux la réalité des besoins et les aspirations des pays.

  7. Attenuation of pressure dips underneath piles of spherocylinders.

    Science.gov (United States)

    Zhao, Haiyang; An, Xizhong; Gou, Dazhao; Zhao, Bo; Yang, Runyu

    2018-05-30

    The discrete element method (DEM) was used to simulate the piling of rod-like (elongated sphero-cylindrical) particles, mainly focusing on the effect of particle shape on the structural and force properties of the piles. In this work, rod-like particles of different aspect ratios were discharged on a flat surface to form wedge-shaped piles. The surface properties of the piles were characterized in terms of angle of repose and stress at the bottom of the piles. The results showed that the rise of the angle of repose became slower with the increase of particle aspect ratio. The pressure dip underneath the piles reached the maximum when the particle aspect ratio was around 1.6, beyond which the pressure dip phenomenon became attenuated. Both the pressure dip and the shear stress dip were quantitatively examined. The structure and forces inside the piles were further analyzed to understand the change in pressure dip, indicating that "bridging" or "arching" structures within the piles were the cause of the pressure dip.

  8. Effect of piles on the seismic response of mosques minarets

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Abdel-Motaal

    2014-03-01

    Minaret (60.0-m height was studied to investigate the effects of soil stiffness, pile length, diameter, and arrangement, on the minaret and pile dynamic behavior. Comparison between study results and conventional analysis method is illustrated. Study results, discussion, and conclusion are given.

  9. The homogenisation of bulk material in blending piles.

    NARCIS (Netherlands)

    Gerstel, A.W.

    1979-01-01

    In this thesis the homogenisation of bulk material in three types of piles is dealt with. The homogenisation implies that the fluctuations of a material proprety in the input flow of the pile are transformed into output fluctuations, whereby the latter ones are evened out. Analyses are presented

  10. Estimating setup of driven piles into Louisiana clayey soils.

    Science.gov (United States)

    2010-11-15

    Two types of mathematical models for pile setup prediction, the Skov-Denver model and the newly developed rate-based model, have been established from all the dynamic and static testing data, including restrikes of the production piles, restrikes, st...

  11. Lateral resistance of piles near vertical MSE abutment walls.

    Science.gov (United States)

    2013-03-01

    Full scale lateral load tests were performed on eight piles located at various distances behind MSE walls. The objective of the testing was to determine the effect of spacing from the wall on the lateral resistance of the piles and on the force induc...

  12. Bulk density and porosity distributions in a compost pile

    NARCIS (Netherlands)

    Ginkel, van J.T.; Raats, P.A.C.; Haneghem, van I.A.

    1999-01-01

    This paper mainly deals with the description of the initial distribution of bulk density and porosity at the moment a compost pile is built or rebuilt. A relationship between bulk density and vertical position in a pile is deduced from theoretical and empirical considerations. Formulae to calculate

  13. Piling up technology of goods irradiated by single plate source

    International Nuclear Information System (INIS)

    Xia Hezhou; Chen Yuxia; Cao Hongyun; Lin Yong; Zhou guoquan

    1999-01-01

    In the irradiation process of piling up goods in static state, four irradiation working sites and single plate source was adopted. The results showed that piling up in this way remarkably raised the irradiation quality of goods. The utilization rate of radioactive ray reached 22.27%

  14. The reactor Melusine - radiation measurements carried out at the start of operation and during the first ascents to power; Pile Melusine - mesures de rayonnement effectuees au demarrage et pendant les premieres montees en puissance

    Energy Technology Data Exchange (ETDEWEB)

    Coutrot, V; Delpuech, J; Fitoussi, L [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This report gives the results of radiation measurements carried out on the first C.E.A. swimming-pool pile, Melusine. The purpose of these measurements, which were carried out during the starting-up period and the first ascents to 1 MW power, is to check the radiation intensity levels near the pile and from this to verify the safety calculation methods used. In addition certain special measurements, such as those performed in and above the water of the swimming-pool, in the channels and outside them etc..., should make it possible eventually to define the conditions under which the pile may be used for special jobs with less protection. In the first part of the report are given the results of radiation measurements carried out during runs at low power plateaux not exceeding 500 W: in particular measurements at variable water levels in the water of the swimming-pool and on the axis of the open channels. The results given in the second part deal with radiation measurements performed in various parts of the premises, studies on the activation of the plugs in the experimental channels and of the materials in the forward compartment, and also of the radioactivity of the swimming-pool water and the air used to cool the channels. (author) [French] Le present rapport a pour but de donner les resultats des mesures de rayonnement effectuees aupres de la premiere pile piscine du C.E.A.: la pile Melusine. Le but de ces mesures, effectuees pendant la periode de demarrage et les premieres montees a la puissance de 1 MW, est de controler les niveaux d'intensite de rayonnement aupres de la pile et par la de juger des methodes de calculs de protection utilisees. D'autre part, certaines mesures plus particulieres, telles que celles effectuees dans l'eau et au-dessus de l'eau de la piscine, dans les canaux et a l'exterieur de ceux-ci, etc..., doivent permettre de definir ulterieurement les conditions d'utilisation de la pile pour des fonctionnements particuliers avec des protections

  15. The Analysis of Soil Resistance During Screw Displacement Pile Installation

    Science.gov (United States)

    Krasinski, Adam

    2015-02-01

    The application of screw displacement piles (SDP) is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT is proposed.

  16. Modeling temperature noise in a fast-reactor pile

    International Nuclear Information System (INIS)

    Kebadze, B.V.; Pykhtina, T.V.; Tarasko, M.Z.

    1987-01-01

    To observe partial overlapping of the heat carrier cross section in piles, leading to local temperature rise or boiling of the sodium, provision is made for individual monitoring of the fuel assemblies with respect to the output temperature. Since the deviation of the mean flow rate through the pile and the output temperature is slight with this anomaly, the temperature fluctuations may provide a more informative index. The change in noise characteristics with partial overlapping of the cross sections occurs because of strong distortion of the temperature profile in the overlap region. The turbulent flow in the upper part of the pile transforms this nonuniformity into temperature pulsations which may be recorded by a sensor at the pile output. In this paper the characteristics of temperature noise are studied for various pile conditions and sensor locations by statistical modeling

  17. Static Tension Tests on Axially Loaded Pile Segments in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    This paper provides laboratory test results of static axially loaded piles in sand. With a newly developed test setup, the pile-soil interface friction was investigated by using an open-ended steel pile segment with a diameter of 0.5 m. Use of a pile length of 1 m enabled the pile-soil interface...... friction to be analyzed at a given soil horizon while increasing the vertical effective stress in the sand. Test results obtained by this approach can be analyzed as single t-z curves and compared to predictions of unit shaft friction from current design methods for offshore foundations. The test results...... showed best agreement with the traditional design method given in the American Petroleum Institute (API) design code. When t-z curves obtained from the test results were compared to t-z curve formulations found in the literature, the Zhang formulation gave good predictions of the initial and post...

  18. SHAKING TABLE TESTS ON SEISMIC DEFORMATION OF PILE SUPPORTED PIER

    Science.gov (United States)

    Fujita, Daiki; Kohama, Eiji; Takenobu, Masahiro; Yoshida, Makoto; Kiku, Hiroyoshi

    The seismic deformation characeteristics of a pile supported pier was examined with the shake table test, especially focusing on the pier after its deformation during earthquakes. The model based on the similitude of the fully-plastic moment in piles was prepared to confirm the deformation and stress characteristic after reaching the fully-plastic moment. Moreover, assuming transportation of emergency supplies and occurrence of after shock in the post-disaster period, the pile supported pier was loaded with weight after reaching fully-plastic moment and excited with the shaking table. As the result, it is identified that the displacement of the pile supported pier is comparatively small if bending strength of piles does not decrease after reaching fully-plastic moment due to nonoccourrence of local backling or strain hardening.

  19. Theoretical study of short pile effect in tunnel excavation

    Science.gov (United States)

    Tian, Xiao-yan; Liu, Jing; Gao, Xiao-mei; Li, Yuan

    2017-09-01

    The Misaki Sato Go ideal elastoplastic model is adopted and the two stage analysis theory is used to study the effect of tunnel excavation on short pile effect in this paper. In the first stage, the free field vertical displacement of the soil at the corresponding pile location is obtained by using empirical formula. In the second stage, the displacement is applied to the corresponding pile location. The equilibrium condition of micro physical differential equation settlement of piles. Then through logical deduction and the boundary condition expressions of the settlement calculation, obtain the pile side friction resistance and axial force of the week. Finally, an engineering example is used to analyze the influence of the change of main parameters on their effects.

  20. Physical Modelling of Cyclic Laterally Loaded Pile in Cohesionless Soil

    DEFF Research Database (Denmark)

    Hansen, Mette; Wolf, Torben K.; Rasmussen, Kristian L.

    Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical in the service......Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical...... in the serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...

  1. Laboratory Testing of Cyclic Laterally Loaded Pile in Cohesionless Soil

    DEFF Research Database (Denmark)

    Roesen, Hanne Ravn; Ibsen, Lars Bo; Hansen, Mette

    2013-01-01

    Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical in the service......Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical...... in the serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...

  2. The Analysis of Soil Resistance During Screw Displacement Pile Installation

    Directory of Open Access Journals (Sweden)

    Krasinski Adam

    2015-02-01

    Full Text Available The application of screw displacement piles (SDP is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque during screw auger penetration in non-cohesive subsoil based on CPT is proposed.

  3. Optimal Design of Sheet Pile Wall Embedded in Clay

    Science.gov (United States)

    Das, Manas Ranjan; Das, Sarat Kumar

    2015-09-01

    Sheet pile wall is a type of flexible earth retaining structure used in waterfront offshore structures, river protection work and temporary supports in foundations and excavations. Economy is an essential part of a good engineering design and needs to be considered explicitly in obtaining an optimum section. By considering appropriate embedment depth and sheet pile section it may be possible to achieve better economy. This paper describes optimum design of both cantilever and anchored sheet pile wall penetrating clay using a simple optimization tool Microsoft Excel ® Solver. The detail methodology and its application with examples are presented for cantilever and anchored sheet piles. The effects of soil properties, depth of penetration and variation of ground water table on the optimum design are also discussed. Such a study will help professional while designing the sheet pile wall penetrating clay.

  4. Ultimate capacity of piles penetrating in weak soil layers

    Directory of Open Access Journals (Sweden)

    Al-Obaidi Ahmed

    2018-01-01

    Full Text Available A pile foundation is one of the most popular forms of deep foundations. They are routinely employed to transfer axial structure loads through the soft soil to stronger bearing strata. Piles generally used to increase the load carrying capacity of the foundation and reduce the settlement of the foundation. On the other hand, many cases in practice where piles pass through different layers of soil that contain weak layers located at different depths and extension, also some time cavities with a different shape, size, and depth are found. In this study, a total of 96 cases is considered and simulated in PLAXIS 2D program aiming to understand the influence of weak soil on the ultimate pile capacity. The piles embedded in the dense sand with a layer of weak soil at different extension and location. The cross section of the geometry used in this study was designed as an axisymmetric model with the 15-node element; the boundary condition recommended at least 5D in the horizontal direction, and (L+5D in the vertical direction where D and L are the diameter and length of pile, respectively. The soil is modeled as Mohr-Coulomb, with five input parameters and the behavior of pile material represented by the linear elastic model. The results of the above cases are compared with the results found in a pile embedded in dense soil without weak layers or cavities. The results indicated that the existence of weak soil layer within the surrounding soil around the pile decreases the ultimate capacity. Furthermore, it has been found that increase in the weak soil width (extension leads to reduction in the ultimate capacity of the pile. This phenomenon is applicable to all depth of weak soil. The influence of weak layer extension on the ultimate capacity is less when it is presentin the upper soil layers.

  5. Analytical representation of time correlation functions and application to relaxation problems; Representation analytique des fonctions de correlation temporelle et application a des problemes de relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Dupuis, M [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires, departement de physico-chimie, services des isotopes stables

    1971-07-01

    Two analytical representations of the Laplace transform of the time autocorrelation of a dynamical variable, namely the moment expansion and Mori's continued fraction expansion, are investigated from the point of view of structure and convergence properties, and the relation between them is established. The general theory is applied first to a dynamical model exactly solvable, the isotopic impurity in a linear chain of coupled harmonic oscillators, and then to two stochastic models recently introduced by Gordon for the rotational diffusion of molecules. In the latter case, the continued fraction expansion yields simple analytical expressions for the infrared absorption band shapes, showing that these models contain all the features of observed shapes in compressed gases, liquids and solutions. (author) [French] Deux representations analytiques de la transformee de Laplace de la fonction d'autocorrelation temporelle d'une variable dynamique, le developpement en moments et le developpement en fraction continue recemment introduit par Mori, sont etudiees du point de vue de leurs proprietes de structure et de convergence, en meme temps que la relation qui existe entre elles est etablie. La theorie generale est appliquee, d'une part, a un modele dynamique exactement soluble, celui d'une particule isotopique dans une chaine lineaire d'oscillateurs harmoniques couples, et, d'autre part, a deux modeles stochastiques recemment proposes par Gordon pour la diffusion rotationnelle des molecules. Dans ce dernier cas, la voie de la fraction continue fournit des expressions analytiques simples pour les formes de bande d'absorption infrarouge, montrant que ces modeles possedent les caracteristiques des formes observees dans les gaz comprimes, les liquides ou les solutions. (auteur)

  6. Des alliances d’action pour faire des enjeux sociétaux une source d’innovation, de création et de transformation

    Directory of Open Access Journals (Sweden)

    Philippe Lemoine

    2012-01-01

    Full Text Available Les rapports entre l’économie et les autres sphères de la société sont en train de se transformer, et avec eux, les expressions de la solidarité et les modèles d’engagement. Parmi eux, les alliances entre acteurs hétérogènes (entreprises, ONG et « social business », pouvoirs publics, acteurs de l’Internet, etc. permettent de s’attaquer aux grands enjeux de ce monde avec davantage de justesse et d’efficacité. En agrégeant des acteurs aux logiques différentes dans une dynamique de co-création, les alliances ouvrent de nouveaux horizons de développement. Avec la Clinton Global Initiative, Bill Clinton s’est donné comme objectif d’encourager les alliances sur des actions généreuses qui soient efficaces et mesurables. Si la dynamique fonctionne dans le monde anglo-saxon, elle peine à s’installer en Europe. Pourtant les acteurs européens disposent de nombreux atouts pour s’engager dans de nouvelles alliances transformatrices de notre monde et auraient tout intérêt, pour ce faire, à se fédérer. Plusieurs membres européens de la Clinton Global Initiative ont ainsi lancé le réseau « The European Network » pour amorcer un mouvement en Europe et donner une ambition européenne à l’engagement sociétal. Cet article décrit les singularités des alliances avant de présenter la structuration de l’action européenne en relation avec la Clinton Global Initiative.

  7. Digitalisation in atomic pile control (1962)

    International Nuclear Information System (INIS)

    Furet, J.

    1962-01-01

    A brief survey is first given of the general theorems of Boodle's algebra and of sequence systems using D.A. Huffmans theory. Some indications are then given concerning the setting-up and the operation of digital computers and also of the principal codes used in digital techniques. It is then shown how digitalisation in atomic pile control makes it possible to use new techniques having the following advantages in particular: greater working safety, a higher degree of centralisation, and suppression of the linear elements. A few examples are given of the application of these techniques to control, particularly with respect to the measurement of the neutronic power and of the period and also of course, to the treatment of the data and the sequence automatisms. The advantage of using digital techniques in the shutdown channels is also examined. Finally a review is given of the technology and the viability of the control devices used. (author) [fr

  8. Diversité des itinéraires migratoires des colons d’un front pionnier amazonien

    Directory of Open Access Journals (Sweden)

    Pascal Sebille

    2008-06-01

    Full Text Available Durante muito tempo, o debate sobre as causas das migrações foi pensado a partir de uma oposição entre migração causada por um evento exterior (guerra, pobreza, etc. e migração decidida por estratégias internas ao quadro familiar. Há mais de dez anos, vem-se tentando construir relações entre esses pontos de vista. A abordagem pelas histórias de vida se encaixa nessas tentativas: uma forma quantitativa de realizar essas pontes se desenvolveu em demografia pela análise dos itinerários biográficos. Mas muitas vezes, busca-se uma razão única ou uma combinação de razões para explicar os comportamentos de todos os membros da população estudada. O nosso objetivo neste artigo é aplicar uma metodologia baseada na realização de tipologias de itinerários biográficos para descrever os diferentes perfis migratórios dos assim chamados assentados da reforma agrária do sudeste do Pará. Baseada em uma amostra de 350 assentados, nossa análise mostra e qualifica a heterogeneidade dos itinerários biográficos, tentando também propor pistas para explicá-la.Alors que depuis longtemps la grande majorité des travaux sur les dynamiques migratoires s’est organisée autour de débats sur les facteurs externes des migrations et sur les stratégies familiales migratoires, la présente recherche s’intéresse aux liens entre ces deux dynamiques en associant l’analyse spatiale de la mobilité et l’étude des trajectoires de vie des individus. L’approche biographique d’analyse des histoires de vie développée en démographie, au cœur de cette étude, permet d’apporter de nouveaux éléments explicatifs à l’interaction entre les facteurs de mobilité et les dynamiques familiales. Grâce à la construction de typologies de parcours migratoires, ce travail permet de rendre compte de la diversité des dynamiques de mobilité et de l’hétérogénéité des profils de migrants. Le front pionnier Amazonien représente un lieu d

  9. Etude de la dynamique de la macrofaune du sol en culture d'ognon

    African Journals Online (AJOL)

    Département Gestion des Ressources Naturelles/Système de Production,. 01 BP 470 ... Agricultural Research and Training of the Institute of the Environment and Agricultural Research (INERA). The objective was to ...... Ecotoxicology and.

  10. Analysis of Wave Fields induced by Offshore Pile Driving

    Science.gov (United States)

    Ruhnau, M.; Heitmann, K.; Lippert, T.; Lippert, S.; von Estorff, O.

    2015-12-01

    Impact pile driving is the common technique to install foundations for offshore wind turbines. With each hammer strike the steel pile - often exceeding 6 m in diameter and 80 m in length - radiates energy into the surrounding water and soil, until reaching its targeted penetration depth. Several European authorities introduced limitations regarding hydroacoustic emissions during the construction process to protect marine wildlife. Satisfying these regulations made the development and application of sound mitigation systems (e.g. bubble curtains or insulation screens) inevitable, which are commonly installed within the water column surrounding the pile or even the complete construction site. Last years' advances have led to a point, where the seismic energy tunneling the sound mitigation systems through the soil and radiating back towards the water column gains importance, as it confines the maximum achievable sound mitigation. From an engineering point of view, the challenge of deciding on an effective noise mitigation layout arises, which especially requires a good understanding of the soil-dependent wave field. From a geophysical point of view, the pile acts like a very unique line source, generating a characteristic wave field dominated by inclined wave fronts, diving as well as head waves. Monitoring the seismic arrivals while the pile penetration steadily increases enables to perform quasi-vertical seismic profiling. This work is based on datasets that have been collected within the frame of three comprehensive offshore measurement campaigns during pile driving and demonstrates the potential of seismic arrivals induced by pile driving for further soil characterization.

  11. Les dynamiques transfrontalières en Afrique de l'Ouest : Analyse ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    31 mai 2007 ... L'intégration économique, politique et sociale de l'Afrique de l'Ouest est reconnue comme un enjeu majeur de développement. Elle se trouve désormais au coeur des agendas politiques de la sous-région. Si des avancées majeures ont pu être enregistrées au niveau institutionnel, celles-ci peinent à se ...

  12. Les Dynamiques Transfrontalières En Afrique De L'ouest

    International Development Research Centre (IDRC) Digital Library (Canada)

    Si l'approche « classique » de l'intégration régionale, qui a jusqu'à ... mettre en exergue une réalité territoriale matérialisée par l'existence d'une frontière ...... La demande alimentaire des métropoles côtières stimule ainsi la production des ...

  13. Système de prévention du risque de renversement latéral pour des véhicules évoluant en milieu naturel

    OpenAIRE

    Richier , M.; Lenain , R.; Thuilot , Benoît; Debain , C.

    2012-01-01

    International audience; Un algorithme dédié aux Véhicules Légers Tout-Terrain (VLTT) permettant l'estimation et l'anticipation du renversement est présenté dans ce papier. Il repose sur une estimation temps réel du Transfert de Charge Latéral (TCL), représentatif des instabilités dynamiques latérales. Le TCL est calculé grâce à un modèle dynamique divisé en deux projections 2D. A partir de ce modèle et d'un système de perception bas prix, un observateur est proposé. Il permet d'estimer en tem...

  14. Etude dynamique de l’environnement des villages romano-byzantins de Syrie du Nord ; localisation des structures parcellaires et cadastrales qui leurs sont liées

    Directory of Open Access Journals (Sweden)

    Georges Tate

    2000-05-01

    Full Text Available L’étude porte sur une région de 30.000 km2, allant de la frontière turque à Homs, et communément appelé "le Plateau Calcaire". Sept cents villages, d’époque romaine et byzantine y ont été recensés. Les objectifs Ils sont de deux types : comprendre l’histoire du peuplement, en particulier l’abondon progressif de très nombreux villages entre le 8éme et le 10ème siècle. A cette fin sont notamment indispensables les connaissances relatives, aux terroirs et aux terres arables effectivement disponi...

  15. Dynamiques des réseaux relationnels et trajectoires sociales d'usage des TIC au moment du passage à la vie adulte

    OpenAIRE

    Fribourg , Bertrand

    2007-01-01

    The socialization process can be understood as movements of proximal interpersonal relationships. Using structural and qualitative information from our longitudinal study, this thesis analyses the development of sixty young people's personal networks over a period of nine years: the process of entering adulthood. This issue is tackled through observation of the domestication of ICT's during this period. The uses of ICT are studied through the complex relation between social networks and indiv...

  16. Modeling of the dynamical combustion of explosives: influence of mechanical properties; Modelisation de la combustion dynamique des explodifs: influence des proprietes mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Picart, D.; Pertuis, C. [CEA Le Ripault, 37 - Tours (France)

    1996-12-31

    Experimental observations performed during the combustion of solid explosives under pressure have shown an unexpected desensitization of the samples when damaged. A simplified method of combustion simulation inside a pressure cell is proposed in this study. The model used is based on the description of the mechanical behaviour of the solid phase. It allows to retrieve the overall experimental results, and in particular the occurrence of anomalous combustion modes. (J.S.) 8 refs.

  17. Analysis of static and dynamic pile-soil-jacket behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Azadi, Mohammad Reza Emami

    1998-12-31

    In the offshore industry, recent extreme storms, severe earthquakes and subsidence of the foundation of jacket platforms have shown that new models and methods must take into account the jacket- pile-soil foundation interaction as well as the non-linear dynamic performance/loading effects. This thesis begins with a review of the state of art pile-soil interaction model, recognizing that most existing pile-soil models have been established based on large diameter pile tests on specific sites. The need for site independent and mechanistic pile-soil interaction models led to the development of new (t-z) and (p-y) disk models. These are validated using the available database from recent large diameter pile tests in the North Sea and Gulf of Mexico. The established static disk models are applied for non-linear static analysis of the jacket-pile-soil system under extreme wave loading. Dynamic pile-soil interaction is studied and a new disk-cone model is developed for the non-linear and non-homogeneous soils. This model is applied to both surface and embedded disks in a soil layer with non-linear properties. Simplified non-linear as well as more complex analysis methods are used to study the dynamic response of the jacket platform under extreme sea and seismic loading. Ductility spectra analysis is introduced and used to study the dynamic performance of the jacket systems near collapse. Case studies are used to illustrate the effects of structural, foundation failure characteristics as well as dynamic loading effects on the overall performance of the jacket-pile-soil systems near ultimate collapse. 175 refs., 429 figs., 70 tabs.

  18. Field Test of Driven Pile Group under Lateral Loading

    Science.gov (United States)

    Gorska, Karolina; Rybak, Jaroslaw; Wyjadlowski, Marek

    2017-12-01

    All the geotechnical works need to be tested because the diversity of soil parameters is much higher than in other fields of construction. Horizontal load tests are necessary to determine the lateral capacity of driven piles subject to lateral load. Various load tests were carried out altogether on the test field in Kutno (Poland). While selecting the piles for load tests, different load combinations were taken into account. The piles with diverse length were chosen, on the basis of the previous tests of their length and integrity. The subsoil around the piles consisted of mineral soils: clays and medium compacted sands with the density index ID>0.50. The pile heads were free. The points of support of the “base” to which the dial gauges (displacement sensors) were fastened were located at the distance of 0.7 m from the side surface of the pile loaded laterally. In order to assure the independence of measurement, additional control (verifying) geodetic survey of the displacement of the piles subject to the load tests was carried out (by means of the alignment method). The trial load was imposed in stages by means of a hydraulic jack. The oil pressure in the actuator was corrected by means of a manual pump in order to ensure the constant value of the load in the on-going process of the displacement of the pile under test. On the basis of the obtained results it is possible to verify the numerical simulations of the behaviour of piles loaded by a lateral force.

  19. ANALYSE DES PERCEPTIONS LOCALES ET DES FACTEURS ...

    African Journals Online (AJOL)

    AISA

    1Faculté des Sciences Agronomiques (FSA), Université d'Abomey-Calavi (UAC), 01 BP 526 Cotonou Bénin. Email : cgbemavo@yahoo.fr. 2Institut National des Recherches Agricoles du Bénin, Centre de Recherches Agricoles d'Agonkanmey (CRA-A),. Laboratoire des Sciences du Sol, Eau et Environnement (LSSEE).

  20. Experimental study of the pile EL3; Etude experimentale de la pile EL3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1958-07-01

    The results of two months' experiments, carried out at low power following the first divergence (4. July 1957) are presented. These experiments dealt with the following points: comparison of experimental and calculated values of the critical size; effects due to the introduction of absorbing materials into the principal experimental facilities, flux distribution measurements especially in these facilities, calibration of safety, control and compensating rods, determination of the average life of the neutrons. (author) [French] On expose les resultats relatifs a deux mois d'experiences effectuees a basse puissance a la suite de la premiere divergence (4 juillet 1957). Ces experiences ont porte sur les points suivants: comparaison des tailles critiques experimentales et calculees, effets dus a l'introduction de corps absorbants dans les principaux dispositifs experimentaux, mesures des distributions de flux particulierement dans ces dispositifs, etalonnage des barres de securite, de reglage et de compensation, determination de la vie moyenne des neutrons. (auteur)

  1. Impact des matériaux biosourcés sur le climat intérieur : Un outil de calcul flexible à l'échelle de la pièce

    OpenAIRE

    Dubois, Samuel; Lebeau, Frédéric

    2014-01-01

    L'impact de l'utilisation de matériaux d'origine végétale sur le climat intérieur, et donc sur le confort des occupants ainsi que la performance énergétique du bâtiment, n'est établi que partiellement. Ces produits présentent des propriétés hygroscopiques et capillaires causant des phénomènes spécifiques liés aux changements de phase dynamiques au sein de la matrice poreuse. Les modèles mathématiques utilisés pour étudier leur comportement hygrothermique de manière détaillée sont souvent des ...

  2. Géomorphologie et sédimentologie d'une plate-forme carbonatée isolée: l'Archipel des Glorieuses, SO Océan Indien

    OpenAIRE

    Prat, Sophie; Jorry, Stephan; Jouet, Gwenael; Le Roy, Pascal; Camoin, Gilbert; Vella, Claude; Caline, Bruno

    2013-01-01

    Améliorer nos connaissances sur la distribution des sédiments carbonatés dans les systèmes récifaux actuels sert à définir des analogues afin de mieux comprendre les réservoirs à hydrocarbures exploités dans les formations récifales fossiles. Bien que le rôle des changements du niveau marin, de la tectonique et de la sédimentation sur la dynamique et l'évolution des plates-formes carbonatés tropicales ait été largement étudié, la variabilité sédimentaire et les facteurs qui contrôlent cette h...

  3. Aspects structurels et fonctionnels de la biodiversité des peuplements de poissons

    Directory of Open Access Journals (Sweden)

    WINEMILLER K. O.

    1995-04-01

    Full Text Available Cet article passe brièvement en revue les relations existant entre la biodiversité des peuplements de poissons et leur fonctionnement écologique. La biodiversité et la structure des peuplements peuvent être décrites, à l'échelle locale, en termes (1 de diversité phylogénétique, (2 de structure des populations, (3 de stratégies démographiques, (4 de diversité morphologique, (5 et de diversité trophique. Un défi majeur est de déterminer les relations qui existent entre la structure des populations et des peuplements et le fonctionnement des peuplements et des écosystèmes. La structure phylogénétique d'un peuplement résulte de l'interaction entre colonisation, extinction et évolution. En dépit du fait que ces facteurs opèrent sur une vaste gamme d'échelles spatiales et temporelles, de grands progrès ont été réalisés dans la modélisation des processus qui sont à la base de la structure génétique et phylogénétique des populations et des peuplements. Les modes de reproduction des poissons sont très variés, et la définition de guildes de reproduction et de stratégies démographiques permet de poser le cadre dans lequel les aspects structurels et fonctionnels peuvent être étudiés. Des études théoriques et empiriques mettent en évidence de fortes relations entre les stratégies démographiques, les variations environnementales et la dynamique des populations. Les poissons présentent une grande diversité morphologique qui, à l'échelle du peuplement, tend à augmenter avec la richesse spécifique. Des relations reliant la morphologie et l'écologie, en termes de fonction et de performance dans l'utilisation du milieu, ont été établies, mais dans certains cas, les tendances prédites sont masquées par des biais d'échantillonnage et la flexibilité du comportement en réponse à la variabilité environnementale. Le spectre des stratégies trophiques manifesté par les poissons est large, au niveau inter

  4. Elementary calculation of the shutdown delay of a pile

    International Nuclear Information System (INIS)

    Yvon, J.

    1949-04-01

    This study analyzes theoretically the progress of the shutdown of a nuclear pile (reactor) when a cadmium rod is introduced instantaneously. For simplification reasons, the environment of the pile is considered as homogenous and only thermal neutrons are considered (delayed neutrons are neglected). Calculation is made first for a plane configuration (plane vessel, plane multiplier without reflector, and plane multiplier with reflector), and then for a cylindrical configuration (multiplier without reflector, multiplier with infinitely thick reflector, finite cylindrical piles without reflector and with reflector). The self-sustain conditions are calculated for each case and the multiplication length and the shutdown delay are deduced. (J.S.)

  5. Gas reactor in-pile safety test project (GRIST-2)

    International Nuclear Information System (INIS)

    Kelley, A.P. Jr.; Arbtin, E.; St Pierre, R.

    1979-01-01

    Although out-of-pile tests may be expected to confirm individual phenomena models in core disruptive accident analysis codes, only in-pile tests are capable of verifying the extremely complex integrated model effects within the appropriate time phase for these accidents. For this reason, the GRIST-2 project, the purpose of which is to design and construct an in-pile helium loop capable of transient safety testing in the TREAT facility in Idaho, forms a cornerstone of the US GCFR safety program. The project organization, experiment program, facility, helium system design, and schedule which have been selected to meet the objectives are described

  6. Batteries observatory: 2001 situation; Observatoire des piles et accumulateurs: la situation en 2001. Rapport sur la mise en oeuvre des dispositions reglementaires relatives aux piles et accumulateurs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-12-01

    This report presents the 2001 situation in France of the commercialization, collection and processing of batteries (non-chargeable and chargeable). The data presented mainly come from the CERFA notifications 11801*01, 11802*01 and 11803*01, and thus present important limitations due to the declaration system and the format of consignment note used. Therefore, two years after the creation of the batteries observatory, the coverage of the battery market remains incomplete. Moreover, some choices were made during the preparation of this report in order to make it more readable. Also, the unit/weight conversions made can lead to a 15% uncertainty and the distinction between portable and non-portable batteries was made on the basis of a weight criterion (lower or greater than 1 kg). Finally, the collection indicators have to be considered with caution because their definition varies from one country to another. (J.S.)

  7. Monitoring moisture content, temperature, and humidity in whole-tree pine chip piles

    Science.gov (United States)

    John Klepac; Dana Mitchell; Jason Thompson

    2015-01-01

    Two whole-tree chip piles were monitored for moisture content, temperature, and relative humidity from October 8th, 2010 to March 16th, 2011 at a location in south Alabama. Initial moisture content samples were collected immediately after chips were delivered to the study location on October 8th for Pile 1 and October 22nd for Pile 2. During pile construction, Lascar...

  8. 40 CFR 761.347 - First level sampling-waste from existing piles.

    Science.gov (United States)

    2010-07-01

    ... existing piles. 761.347 Section 761.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... from existing piles. (a) General. Sample piles that are either specifically configured for sampling... alternate sampling plan in accordance with § 761.62(c). (b) Specifically configured piles. A specifically...

  9. Pile mixing increases greenhouse gas emissions during composting of dairy manure

    Science.gov (United States)

    The effect of pile mixing on greenhouse gas (GHG) emissions from stored dairy manure was determined using large flux chambers designed to completely cover pilot-scale manure piles. GHG emissions from piles that were mixed four times during the 80 day trial were about 20% higher than unmixed piles. ...

  10. Estimating volume, biomass, and potential emissions of hand-piled fuels

    Science.gov (United States)

    Clinton S. Wright; Cameron S. Balog; Jeffrey W. Kelly

    2009-01-01

    Dimensions, volume, and biomass were measured for 121 hand-constructed piles composed primarily of coniferous (n = 63) and shrub/hardwood (n = 58) material at sites in Washington and California. Equations using pile dimensions, shape, and type allow users to accurately estimate the biomass of hand piles. Equations for estimating true pile volume from simple geometric...

  11. The effect of loading rate on pile bearing capacity of saturated sand

    NARCIS (Netherlands)

    Archeewa, E.

    2005-01-01

    Pile load tests are commonly used by engineers to determine its bearing capacity. At present, there are three methods of pile load tests: the static, the dynamic and the quasi-static test. The static pile load test is done by applying an axial load on the pile with a long duration. The dynamic and

  12. Comparison of Three Different Methods for Pile Integrity Testing on a Cylindrical Homogeneous Polyamide Specimen

    Science.gov (United States)

    Lugovtsova, Y. D.; Soldatov, A. I.

    2016-01-01

    Three different methods for pile integrity testing are proposed to compare on a cylindrical homogeneous polyamide specimen. The methods are low strain pile integrity testing, multichannel pile integrity testing and testing with a shaker system. Since the low strain pile integrity testing is well-established and standardized method, the results from it are used as a reference for other two methods.

  13. Experiments prior to construction of the Rapsodie reactor (1962); Experiences preliminaires a la construction de la pile rapsodie (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Vautrey, L; Zaleski, C P [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1962-07-01

    ', maintes etudes experimentales, d'ordre hydraulique, thermique et mecanique ont ete faites ou sont envisagees pour verifier la validite des principes adoptes dans l'avant rojet. Ce memoire traite des plus importants: 1. Etudes d'elements de circuits de refroidissement: pompes a sodium (mecaniques ou electromagnetiques), eohangeurs Na-Nak et Nak-air, appareils de mesures (debits, temperatures), circuits de purification du sodium, etc. 2. Etudes de refroidissement des assemblages combustibles et fertiles; a) etude du refroidissement par le sodium, menee a l'aide de maquettes hydrauliques (echelle 1 ou superieure a 1), reproduisant l'ecoulement du fluide de refroidissement dans les tuyauteries, a l'amont des elements combustibles et fertiles et a l'interieur de ceux i; b) etude du refroidissement par gaz et par immersion dans le plomb, utilise pendant les operations de la manutention et de stockage. 3. Etudes de dispositifs speciaux du reacteur: joint tournant liquefiable, parties de mecanismes des barres de controle. 4. Etude du bloc pile et des circuits de refroidissement dans leur ensemble. Cette etude doit commencer a la fin de cette annee. Les installations, en cours d'achevement, reproduisent, a l'echelle 1, celles prevues dans le projet et comportent: le bloc pile auquel est associe un circuit de sodium a grand debit permettant les essais de duree et la realisation de chocs thermiques et, en annexe, un circuit d'essai de barres de controle; l'installation complete des circuits de refroidissement de 1 MW et de 10 MW dont les performances, dans les differents cas de fonctionnement, pourront etre verifiees. 5. Etude de securite effectuee sur une maquette a 1 echelle 3/10 de l'ensemble du bloc pile et de ses protections, dont l'objet est la limitation des consequences d'une hypothetique liberation d'energie accidentelle, d'allure explosive. (auteurs)

  14. Un probleme d’identification. Correction du modeles analytique en utilisat des données expérimentales

    Directory of Open Access Journals (Sweden)

    Gabriela Covatariu

    2009-01-01

    Full Text Available La procédure de correction d’un modele analytique adopté pour une structure de construction est précédée d’une comparaison entre le set des données expérimentales et celui des données analytiques, pour une vérification préliminaire concernant la correspondance raisonnable entre ces données. Pour l’identification dynamique des parametres ont été élaborées diverses méthodes de correction des matrices de rigidité et de l’amortissement qui ont a leur base la méthode des moindres carrés dans le domaine des fréquences. L’algorithme proposé a comme résultat la correction de la matrice de rigidité d’un modele de calcul en utilisant comme données d’entrée seulement celles enregistrées pendant les essais expérimentaux.

  15. Pile foundation response in liquefiable soil deposit during strong earthquakes. ; Centrifugal test for pile foundation model and correlation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Y.; Miura, K. (Kajima Corp., Tokyo (Japan)); Scott, R.; Hushmand, B. (California Inst. of Technology, California, CA (United States))

    1992-09-30

    For the purpose of studying the pile foundation response in liquefiable soil deposit during earthquakes, a centrifugal loading system is employed which can reproduce the stress conditions of the soil in the actual ground, and earthquake wave vibration tests are performed in dry and saturated sand layers using a pile foundation model equipped with 4 piles. In addition, the result of the tests is analyzed by simulation using an analytic method for which effective stress is taken into consideration to investigate the effectiveness of this analytical model. It is clarified from the result of the experiments that the bending moment of the pile and the response characteristics of the foundation in the pile foundation response in saturated sand are greatly affected by the longer period of acceleration wave form of the ground and the increase in the ground displacement due to excess pore water pressure buildup. It is shown that the analytical model of the pile foundation/ground system is appropriate, and that this analytical method is effective in evaluating the seismic response of the pile foundation in nonlinear liquefiable soil. 23 refs., 21 figs., 3 tabs.

  16. Numerical Simulation for the Soil-Pile-Structure Interaction under Seismic Loading

    Directory of Open Access Journals (Sweden)

    Lifeng Luan

    2015-01-01

    Full Text Available Piles are widely used as reinforcement structures in geotechnical engineering designs. If the settlement of the soil is greater than the pile, the pile is pulled down by the soil, and negative friction force is produced. Previous studies have mainly focused on the interaction of pile-soil under static condition. However, many pile projects are located in earthquake-prone areas, which indicate the importance of determining the response of the pile-soil structure under seismic load. In this paper, the nonlinear, explicit, and finite difference program FLAC3D, which considers the mechanical behavior of soil-pile interaction, is used to establish an underconsolidated soil-pile mode. The response processes of the pile side friction force, the pile axial force, and the soil response under seismic load are also analyzed.

  17. Experimental Comparison of Statically and Cyclically Loaded Non-Slender Piles in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    rigid form of motion. The Winkler model approach, employing p-y curves to describe the soil-pile interaction, is often employed as the design method for laterally loaded piles. The p-y curve formulation, currently recommended by the American Petroleum Institute and Det Norske Veritas, is based on tests...... on slender piles with length to diameter ratios larger than ten and outer pile diameters less than two meters. Hence, the pile tests that form the basis of the currently recommended p-y curve formulation are conducted with use of piles that exhibits a flexible behaviour, which is in contrast to the piles...... used as foundation for modern offshore wind energy converters. The aim of the present work is to investigate the pile behaviour for non-slender piles by means of small-scale testing. The pile behaviour is investigated and compared for both static and cyclic loading. When conducting small-scale tests...

  18. The Use of Tactile Sensors and PIV Analysis for Understanding the Bearing Mechanism of Pile Groups.

    Science.gov (United States)

    You, Zhijia; Chen, Yulong

    2018-02-06

    Model tests were carried out in dry silica sand under pile loading and visualizing observation to investigate the behavior of a pile group. The pile group consisted of nine cylindrical model piles of 40 mm in diameter in most tests or three rectangular parallelepiped model piles in the visualizing observation. Pile spacings of 200 mm and 100 mm between pile centers were used in the models. Tactile sensors were installed to measure the pressure distribution in the ground and colored sand layer with particle image velocimetry (PIV) analysis to reveal the ground deformation in addition to strain gauges inside the model piles to investigate the interaction among group piles. The tests results showed that a narrower spacing between piles resulted in a wider affected area of the ground and the interaction was more significant below the tips.

  19. A Systematic Approach for Determining Vertical Pile Depth of Embedment in Cohensionless Soils to Withstand Lateral Barge Train Impact Loads

    Science.gov (United States)

    2017-01-30

    at the top of the piles, vertical pile groups must be designed to exhibit long-pile behavior (e.g., nominal change of deflection at the pile cap...smeared crack” pile properties (and thus, the advisability of using COM624G for analysis) for the incremental pushover design method, as compared...to show nominal change as the pile-tip depth is increased. This same behavior should exist for piles in any homogeneous, cohesionless soil. From

  20. An Estimating Formula of Lateral Load Acting on Stabilizing Piles for Landslide

    OpenAIRE

    尾崎, 叡司; 石田, 陽博

    1984-01-01

    An estimating method of lateral load acting on stabilizing piles in a raw due to the plastic deformation of soil for landslide was discussed in this paper. Special emphasis was put on the problems of the space between stabilizing piles and of lateral load induced in piles through the surrounding soils due to plastic deformation in the vicinity of piles. In order to obtain an analytical result of the lateral load acting on stabilizing piles, the authors tried to solve the equilibrium equation ...