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  1. Etudes sur le Portugal au Temps de l'Humanisme

    Directory of Open Access Journals (Sweden)

    J. Cruz Costa

    1953-06-01

    Full Text Available BATAILLON (Marcel. — Etudes sur le Portugal au Temps de l'Humanisme.  Acta Universitatis Conimbrigencis, 1952, 309 pp. (Primeiro Parágrafo do Artigo O Prof. Marcel Bataillon, erudito dos mais inteligentes da França atual, autor de uma obra que é hoje impr:scindível para quem pretenda estudar o humanismo renascentista na Espanha ou em Portugal, diríamos melhor, talvez: para quem pretenda estudar o Humanismo e a Renascença, — acaba de publicar, na coleção Acta Universitatis Conimbrigencis, êste volume no qual reune alguns trabalhos da mais alta importância para o conhecimento de muitos aspectos da vida espiritual portuguêsa do século XVI.

  2. Study relating to the physico-chemical behaviour of heavy water in nuclear reactors; Etudes relatives au comportement physico-chimique de l'eau lourde dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Chenouard, J; Dirian, G; Roth, E; Vignet, P; Platzer, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1959-07-01

    Chemical and isotope pollution, and radiolytic decomposition are the two most important ways in which heavy water becomes degraded in nuclear reactors. Chemical pollution has led to the creation of ion exchange purification loops specially designed for reactors: the report contains a description in detail of the application of this purification method in CEA research reactors, including the analysis required, results obtained, and their interpretation. The intelligence obtained on radiolytic decomposition with the same facilities is also discussed, as well as the recombination apparatus and control equipment utilized. Finally, investigation to date in the CEA on recombination circuits for power reactors is also discussed. (author) [French] Parmi les degradations subies par l'eau lourde dans les reacteurs nucleaires, les deux plus importantes sont la pollution chimique et isotopique et la decomposition radiolytique. La pollution chimique a conduit a mettre au point pour le cas particulier des reacteurs, des circuits d'epuration par echange d'ions. On decrit ici en detail la mise en oeuvre de cette methode dans les reacteurs de recherche du CEA; les controles qu'elle necessite, les resultats obtenus et leur interpretation. En ce qui concerne la dissociation radiolytique de l'eau, les renseignements obtenus sur ces memes reacteurs sont communiques, ainsi que les details des dispositifs de recombinaison et des moyens de controle. Enfin, on fait le point des etudes poursuivies au CEA sur ces memes problemes de recombinaison dans le cas des reacteurs de puissance. (auteur)

  3. Study relating to the physico-chemical behaviour of heavy water in nuclear reactors; Etudes relatives au comportement physico-chimique de l'eau lourde dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Chenouard, J.; Dirian, G.; Roth, E.; Vignet, P.; Platzer, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1959-07-01

    Chemical and isotope pollution, and radiolytic decomposition are the two most important ways in which heavy water becomes degraded in nuclear reactors. Chemical pollution has led to the creation of ion exchange purification loops specially designed for reactors: the report contains a description in detail of the application of this purification method in CEA research reactors, including the analysis required, results obtained, and their interpretation. The intelligence obtained on radiolytic decomposition with the same facilities is also discussed, as well as the recombination apparatus and control equipment utilized. Finally, investigation to date in the CEA on recombination circuits for power reactors is also discussed. (author) [French] Parmi les degradations subies par l'eau lourde dans les reacteurs nucleaires, les deux plus importantes sont la pollution chimique et isotopique et la decomposition radiolytique. La pollution chimique a conduit a mettre au point pour le cas particulier des reacteurs, des circuits d'epuration par echange d'ions. On decrit ici en detail la mise en oeuvre de cette methode dans les reacteurs de recherche du CEA; les controles qu'elle necessite, les resultats obtenus et leur interpretation. En ce qui concerne la dissociation radiolytique de l'eau, les renseignements obtenus sur ces memes reacteurs sont communiques, ainsi que les details des dispositifs de recombinaison et des moyens de controle. Enfin, on fait le point des etudes poursuivies au CEA sur ces memes problemes de recombinaison dans le cas des reacteurs de puissance. (auteur)

  4. Contribution to the study of several chemical hazards in the Centre d'Etudes Nucleaires of Fontenay-aux-Roses; Contribution a l'etude de quelques nuisances chimiques au centre d'etudes nucleaires de Fontenay-aux-Roses

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    Megemont, C; Grau, C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-10-01

    From the checking of 2750 index cards of hazards, the study relates the distribution of the chemical hazards in the Centre d'Etudes Nucleaires of Fontenay-aux-Roses. Those concerning the greatest number of agents in the Centre are classified according to the categories corresponding to the different conditions of working. Thus, the most important are put forward. Then, the authors rapidly make a review of hazards which may have some special interest because they appear more specific of the nuclear energy or because they are the most frequently noted on the index cards of hazards. The case of the tributylphosphate is studied more precisely. (authors) [French] A partir de l'examen de 2750 fiches de nuisances, l'etude porte sur la repartition des nuisances chimiques au Centre d'Etudes Nucleaires de Fontenay-aux-Roses. Celles qui concernent le plus grand nombre d'agents du Centre sont classees selon les categories correspondant aux differentes conditions de travail. Les plus importantes d'entre elles sont ainsi mises en evidence. | Les auteurs passent ensuite en revue, rapidement, les nuisances qui peuvent presenter un interet particulier soit parce qu'elles semblent plus specifiques de l'Energie Nucleaire, soit parce qu'on les rencontre le plus frequemment sur les fiches de nuisances. Le cas du tributylphosphate est envisage de facon plus detaillee. (auteurs)

  5. Pratique de la transfusion sanguine perioperatoire au Togo: etude ...

    African Journals Online (AJOL)

    But: relever les différents types, les indications, les modalités et les complications de la transfusion sanguine périopératoire. Patients et méthodes : étude prospective, descriptive multicentrique sur 6 mois (1er août 2013 au 31 janvier 2014) sur les transfusions sanguines faites durant la préparation pré opératoire, en per ...

  6. Development of mercury porosimeter. Application to nuclear graphite studies (1961); Mise au point d'un porosimetre a mercure. Application a l'etude des graphites nucleaires (1961)

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-07-01

    A mercury porosimeter, model IFP-CEA, has been developed for application to nuclear graphite studies. The apparatus is based on the capillary depression phenomenon. The relationship between the radius of a pore and the pressure at which mercury fills it is pr = -2 {sigma} cos {theta} ( {sigma} is the surface tension, {theta} the angle of contact of the mercury). After some theoretical consideration, the apparatus is described. The mercury pressure is increased step-wise from 0 to 1000 kg/cm{sup 2} thus yielding the complete distribution of pores from 92 {mu} to 75 A. Results are, then presented concerning nuclear graphites which show the evolution of the porous structure under the effect of bitumen impregnation. In general, the volume of the large pores decreases while that of the small pores increases. The structure of impregnated products appears to depend to a certain extent on that of the starting materials. It has also been possible to study other products with this porosimeter; the range of measurements possible is such that it may be used for the study of the majority of porous materials. (authors) [French] Un porosimetre a mercure modele IFP-CEA a ete mis au point en vue de son application a l'etude de graphites nucleaires. Le fonctionnement de l'appareil repose sur le phenomene de depression capillaire. On etablit la relation existant entre le rayon r d'un pore et la pression p pour laquelle le mercure peut y penetrer: pr = -2 {sigma} cos {theta} ( {sigma} tension superficielle, {theta} angle de contact du mercure). Apres quelques considerations theoriques, l'appareil utilise est decrit. Il permet de faire varier par palier la pression du mercure entre 0 et 1000 kg/cm{sup 2} et d'etablir ainsi la distribution complete des rayons de pores compris entre 92 {mu} et 75 A. Les resultats d'une etude faite sur des graphites nucleaires sont alors presentes faisant apparaitre l'evolution de la structure poreuse sous l'effet des impregnations au brai. D'une facon

  7. Study of Au+Au relativistic collisions with the Fopi-Phase I detector; Etude des collisions relativistes Au+Au avec le detecteur Fopi-Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Dupieux, P

    1995-01-01

    Au+Au relativistic collisions, in a 100-1000 MeV energy domain per nucleon, are described. Experiments have been carried out with the SIS accelerator at GSI/Darmstadt. Data are analysed with the FOPI-phase I detector. These data are compared with IQMD model (Isospin Quantum Molecular Dynamics) Predictions. (S.G). 80 refs., 77 figs., 5 tabs.

  8. Etude s?ro-?pid?miologique de la leishmaniose canine au centre du Maroc

    OpenAIRE

    Fellah, Hajiba; Doughmi, Oursula; Maniar, Sa?d; Lalami, Abdelhakim El Ouali

    2014-01-01

    Dans le monde, la leishmaniose visc?rale humaine est connue pour avoir comme principale source d'infection les Canid?s domestiques et sauvages. Au centre du Maroc, les donn?es ?pid?miologiques, cliniques et parasitologiques sur la leishmaniose canine, sont quasiment inexistantes. Ce travail traite une ?tude prospective au cours de laquelle 61 s?rums canins ont ?t? analys?s par un test rapide et par l'immunofluorescence indirecte. La sensibilit? du test rapide par rapport ? celle de l'immunofl...

  9. Exploitations agricoles climate-intelligentes? Etudes de cas au Burkina Faso et en Colombie

    NARCIS (Netherlands)

    Andrieu, N.; Pédelahore, P.; Howland, F.; Descheemaeker, K.K.E.

    2015-01-01

    Comment satisfaire la sécurité alimentaire tout en s'adaptant au changement climatique et en l'atténuant ? Quelles sont les principales menaces pesant sur les agricultures du Sud ? Comment les agriculteurs du Sud répondent-ils à ces menaces ? Quelles sont les propositions de la recherche agronomique

  10. Observation of allotropic transformations of plutonium with a hot stage microscope; Etude des transformations allotropiques du plutonium au microscopic a platine chauffante

    Energy Technology Data Exchange (ETDEWEB)

    Mars, J; Spftiet, B [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    A hot stage microscope designed for the examination of plutonium and its alloys is described. This apparatus was used to study the {alpha} {r_reversible} {beta} and {delta} {r_reversible} {epsilon} allotropic transformations of pure or {beta} and {delta} stabilised plutonium. The {alpha} {yields} {beta} transformation is typically a nucleation and growth process. Some particularities caused by the internal stresses due to the volume change during this transformation are examined. The kinetics has been studied as a function of these stresses and a temperature dependent activation energy for nucleation has been deduced. The {beta} {yields} {alpha} transformation presents a memory effect which implies an orientation relationship between the two phases. This fact is probably caused by the stresses created during the {beta} {yields} {alpha} transition. The {beta} {r_reversible} {gamma} and {delta} {r_reversible} {epsilon} transformations are also diffusion governed processes. (authors) [French] On decrit un microscope a platine chauffante permettant l'examen du plutonium et de ses alliages. Cet appareil a servi a l'etude des transformations {alpha} {r_reversible} {gamma} et {delta} {r_reversible} {epsilon} du plutonium pur ou stabilise en phase {beta} et {delta}. La transformation {alpha} {yields} {beta} est une transformation typique par germination et croissance; elle presente des caracteristiques bien particulieres qui sont dues aux contraintes internes qui prennent naissance au changement de volume a la transformation; la cinetique a ete etudiee en fonction de ces contraintes, et on en a deduit une energie d'activation pour la germination variable avec la temperature. La transformation {beta} {yields} {alpha} presente un effet de memoire qui suppose une relation d'orientation entre les deux phases; ce phenomene semble lie comme auparavant aux contraintes creees par le passage {beta} {yields} {alpha}. Les transformations {beta} {r_reversible} {gamma} et {delta} {r

  11. The formation of scientists and technicians at the 'Centre d'Etudes Nucleaires' at Saclay; Formation des scientifiques et des techniciens au Centre d'Etudes Nucleaires de Saclay

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

    1958-07-01

    The considerable needs in research workers and scientists which are asked by the nuclear energy obliged the Commissariat a l'Energie atomique to deal with a particular effort to increase the quantitative and qualitative formation of scientists. Most various ways have been used. 1- A National Institute of Nuclear Sciences and Nuclear Techniques was created, by a joint decree of the Prime Minister and the Minister for National Education (june 18, 1957). This Institute of Higher Teaching (250 students) indulges in the following matters: atomic engineering, quantum mechanics, theory and technic of particle accelerators, special metallurgy, radiobiology, thermic and mechanics of fluids. 2- An associated centre of the 'Conservatoire National des Arts et Metiers' waeated (200 students) for technical assistants, drawers, etc. 3- In contribution with both electronic industry and Ministry of Work, the Centre d'Etudes Nucleaires contributes to an accelerated formation of technical assistants into Professional Centres. Conclusion: Training of scientists and research workers is one of the most important activities of the Centre d'Etudes Nucleaires de Saclay. Without losing its technical efficiency, it has supplied and varied means adapted to the various purposes that we shall reach. (author)Fren. [French] Les besoins considerables actuels et previsibles en chercheurs et scientifiques necessites par l'avevement de l'energie nucleaire imposaient au Commissariat a I'Energie atomique un effort particulier pour augmenter la formation quantitative et qualitative des scientifiques. Les moyens les plus divers ont ete mis en oeuvre: 1- Creation de l'Institut National des Sciences et Techniques Nucleaires par decret de la Presidence du Conseil et de l'Education Nationale en date du 18.6.57. Cet Institut d'Enseignement Superieur (250 etudiants) donne des cours en: genie atomique, mecanique quantique, theorie et technique des Accelerateurs de particules, metallurgie speciale, radiobiologie

  12. Study of thick, nuclear-compensated silicon detectors; Etude des detecteurs epais au silicium compense nucleairement

    Energy Technology Data Exchange (ETDEWEB)

    Le Coroller, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-09-01

    A study is made here, from the point of view of the realization and the performance, of thick nuclear-compensated silicon detectors. After recalling the need for compensation and reviewing the existing methods, the author describes in detail the controlled realization of thick detectors by nuclear compensation from the theoretical and experimental points of view. The practical precautions which should be observed are given: control of the homogeneity of the starting material, control of the evolution of the compensation, elimination of parasitic processes. The performances of the detectors obtained are then studied: electrical characteristics (current, life-time) on the one hand, detection and spectrometry of penetrating radiations on the other hand. The results show, that the compensated diodes having an effective thickness of two millimeters operate satisfactorily as detectors for applied voltages of about 500 volts. The resolutions observed are then about 2 per cent for mono-energetic electrons and about 4 per cent for the gamma; they can be improved by the use of a pre-amplifier of very low background noise. (author) [French] Les detecteurs epais au silicium compense nucleairement sont etudies ici du double point de vue realisation et performances. Apres un rappel sur la necessite de la compensation et les procedes existants, la realisation controlee des detecteurs epais par compensation nucleaire est decrite en detail sous l'aspect theorique et l'aspect experimental. On met en evidence les precautions a prendre dans la pratique: controle de l'homogeneite du materiau de base, controle de l'evolution de la compensation, elimination des processus parasites. On etudie ensuite les performances de detecteurs obtenus : caracteristiques electriques (courant, duree de vie) d'une part, d'autre part detection et spectrometrie des rayonnements penetrants. Les resultats montrent que les diodes compensees ayant une epaisseur utile de deux

  13. Study of thick, nuclear-compensated silicon detectors; Etude des detecteurs epais au silicium compense nucleairement

    Energy Technology Data Exchange (ETDEWEB)

    Le Coroller, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-09-01

    A study is made here, from the point of view of the realization and the performance, of thick nuclear-compensated silicon detectors. After recalling the need for compensation and reviewing the existing methods, the author describes in detail the controlled realization of thick detectors by nuclear compensation from the theoretical and experimental points of view. The practical precautions which should be observed are given: control of the homogeneity of the starting material, control of the evolution of the compensation, elimination of parasitic processes. The performances of the detectors obtained are then studied: electrical characteristics (current, life-time) on the one hand, detection and spectrometry of penetrating radiations on the other hand. The results show, that the compensated diodes having an effective thickness of two millimeters operate satisfactorily as detectors for applied voltages of about 500 volts. The resolutions observed are then about 2 per cent for mono-energetic electrons and about 4 per cent for the gamma; they can be improved by the use of a pre-amplifier of very low background noise. (author) [French] Les detecteurs epais au silicium compense nucleairement sont etudies ici du double point de vue realisation et performances. Apres un rappel sur la necessite de la compensation et les procedes existants, la realisation controlee des detecteurs epais par compensation nucleaire est decrite en detail sous l'aspect theorique et l'aspect experimental. On met en evidence les precautions a prendre dans la pratique: controle de l'homogeneite du materiau de base, controle de l'evolution de la compensation, elimination des processus parasites. On etudie ensuite les performances de detecteurs obtenus : caracteristiques electriques (courant, duree de vie) d'une part, d'autre part detection et spectrometrie des rayonnements penetrants. Les resultats montrent que les diodes compensees ayant une epaisseur utile de deux millimetres fonctionnent

  14. Electron microscope study of irradiated beryllium oxide; Etude au microscope electronique de l'oxyde de beryllium irradie

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-06-01

    utilisant des echantillons frittes. Les fractures sont examinees sous differents aspects. Ce sont les frittes les plus denses a fractures intragranulaires qui sont les plus interessants pour l'etude microscopique. Le 'pore' resultant du frittage est differencie de la 'bulle' qui peut se former au cours de traitements thermiques ulterieurs par suite de reactions donnant naissance a des gaz. Apres irradiation, la fragilisation intergranulaire est importante. Par recuit, on suit l'evolution des gaz, produits par les reactions (n. 2n) et (n, {alpha}), qui s'accumulent aux joints de grains. L oxyde de beryllium irradie est ensuite etudie par transmission. Pour cela, une methode simple a ete mise au point; elle consiste a examiner les eclats de cristaux broyes. Les amas de defauts ponctuels, formes par les neutrons, sont ainsi mis en evidence dans les cristaux irradies aux trois doses suivantes: 6.10{sup 19}, 9.10{sup 19} et 2.10{sup 20} n{sub r}.cm{sup -2} a une temperature inferieure a 100 deg. C. Pour l'irradiation a 6.10{sup 19} n{sub r}.cm{sup -2} les defauts sont a peine visibles mais a 2.10{sup 20} n{sub r}.cm{sup -2} les cristaux sont cribles d'amas alors que les lignes de Kikuchi ont disparu des diagrammes de microdiffraction. L'evolution des amas de defauts en boucles de dislocation est etudiee par des recuits successifs. L'energie d'activation de 0.37 eV, calculee a partir des courbes de recuits, incite a penser que ce sont les defauts interstitiels qui se condensent en boucles de dislocation. Des echantillons irradies a haute temperature sont egalement etudies (650, 900 et 1100 deg. C). Dans ceux-ci les boucles de dislocation atteignent un etat d'equilibre different de celui des precedentes. Ces dernieres boucles de dislocation sont etudiees plus specialement et leur vecteur de Burgers est determine par microdiffraction. (auteur)

  15. Comparative study of the creep behaviour of single crystals and polycrystals of alpha uranium; Etude comparee du comportement au fluage de l'uranium alpha mono et polycristallin

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-03-01

    In the first chapter, one describes the creep machine developed to study the deformation of uranium at high temperature in vacuum with a continuous recording. The second chapter presents the results concerning the polycrystals of uranium. The application of the DORN method gives an activation energy for creep of 42 {+-} 2 Kc, above 550 Celsius degrees, equal to the activation energy for self-diffusion. The study of the variation of the creep rate with the applied stress and the metallographic observations of the deformation induced polygonization allow to conclude that the deformation is controlled by climb of dislocations. In the third chapter, the deformation above 550 Celsius degrees of single crystals of uranium (obtained by {beta} {yields} {alpha} change) is studied. The major deformation mode is slip. The preexisting polygonization of these single crystals is very stable and the disorientation between adjacent sub-grains increases with the deformation. The activation energy for creep is higher than that for polycrystals. These results show the influence of the polygonization due to the {beta} {yields} {alpha} change on the creep behaviour of {alpha} uranium. (authors) [French] Dans le premier chapitre, on decrit la machine de fluage sous vide a enregistrement continu, mise au point pour etudier le phenomene. Le deuxieme chapitre presente les resultats relatifs aux polycristaux. L'utilisation de la methode de DORN a permis de constater que, au-dessus de 550 degres Celsius, l'energie d'activation pour le fluage avait une valeur constante egale a 42 {+-} 2 Kc, voisine de la chaleur d'autodiffusion. L'etude de l'influence de la contrainte appliquee sur la vitesse de fluage et l'observation micrographique de la polygonisation developpee au cours de la deformation permettent de conclure que le phenomene est controle par la montee des dislocations. Dans le troisieme chapitre, on etudie le comportement au fluage au-dessus de 550 C des monocristaux obtenus par

  16. Criticality studies; Etudes de criticite

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D; Lecorche, P; Clouet d' Orval, Ch [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Criticality studies made at the Commissariat a l'Energie atomique deal on the one hand with experiments on plutonium and uranium solutions, on the other hand with theoretical work on the development and use of computation, methods for the resolution of problems concerning the nuclear safety of chemical and metallurgical plants. I - Since 1958 the experimental studies have dealt with homogeneous media constituted by a fissile salt dissolved in light water. Developed using the reactor Proserpine, the experiments have been carried on at Saclay on the Alecto assemblies where solutions of plutonium or of 90 p.100 - enriched uranium can be made critical. The results already obtained relate to critical masses of cylindrical tanks of diameters from 20 to 50 cm. reflected in several ways (water, concrete, etc. . ) at concentrations up to 100 g/liter. Physical measurements (spectra, reactor noises) and interaction measurements complete the results. Other experiments relating to plutonium solutions were begun in 1963, at the Valduc Center. They deal with the study of critical masses of annular vessels of external diameter 50 cm and internal diameter varying from 10 to 30 cm. These vessels can be water reflected internally, externally, or both. Two of these vessels have been studied in interaction for various geometries. Slabs of various thicknesses were also studied. II - The studies thus undertaken allowed the development of methods of computation which have been tested on several experiments. Particular use has been made of the possibilities of calculations based on transport theory and on Monte Carlo methods. All these theoretical studies are applied to the design and control of industrial plants from the point of view of safety. (authors) [French] Les etudes de criticite effectuees au CEA comportent d'une part des experiences sur des solutions de plutonium et d'uranium enrichi, d'autre part des travaux theoriques portant sur la mise au point et l'exploitation de methodes

  17. Study methods for the drillings around the underground nuclear explosions in the Sahara. Part 1. study of rock samples; Methodes d'etude des forages realises autour des explosions nucleaires souterraines au Sahara. Premiere partie: etude des echantillons de roche

    Energy Technology Data Exchange (ETDEWEB)

    Derlich, S [Commissariat a l' Energie Atomique, Bruyers-le-Chatel (France). Centre d' Etudes

    1969-07-01

    An examination of the mechanical effects produced on rocks by an underground nuclear explosion calls for the use of particular means of exploration which are described in this report, special attention being paid to the equipment used in connection with the French nuclear tests in the Sahara. The drilling methods used (rotary and turbo-drilling) are adapted to the particular conditions of the sampling programme, to the radioactivity and to the temperature in the region of the explosion. A study of the samples makes it possible to obtain the new characteristics of the rock and to assess the chemical and mechanical transformations which it has undergone. An examination of the core obtained from the drilling, together with a knowledge of the drilling parameters (depth of the probe, sample recovery, etc...), makes it possible to study the extent and the characteristics of the zones which have been damaged to different degrees according to their distance from the zero point: cavity, strongly powdered zone, fractured zone, chimney, zones containing high stresses leading to a particular type of fracture of the cores. The problems connected with the interpretation of the results are also presented. (author) [French] L'examen des effets mecaniques provoques par une explosion nucleaire souterraine sur la roche necessite la mise en oeuvre de moyens d'exploration particuliers dont l'expose fait l'objet de ce rapport, essentiellement pour les moyens utilises autour des essais nucleaires francais au Sahara. Les methodes de forage (rotary et turboforage) sont adaptees aux conditions particulieres dues au programme d'echantillonnage, a la radioactivite et a la temperature regnant a proximite du point de tir. L'etude des echantillons permet la determination des nouveaux caracteres de la roche et de ses transformations chimique et mecanique. L'examen des carottes et l'utilisation des parametres de forage (cotes sondeurs, recuperation des echantillons, etc...) permettent d'etudier l

  18. Etude de trois souches d'Arthrobotrys oligospora : Caractérisation biologique et effets sur Meloidogyne mayaguensis parasite de la tomate au Sénégal

    Directory of Open Access Journals (Sweden)

    Gueyei, M.

    1997-01-01

    Full Text Available Etude de trois souches d'Arthrobotrys oligospora : Caractérisation biologique et effets sur Meloidogyne mayaguensis parasite de la tomate au Sénégal. Three strains (ORS 18690 S2, ORS 18691 S6 and ORS 18693 S5 of the nematophagous fungus Arthrobotrys oligospora have been isolated in Senegal for the first time. In vitro, two strains (ORS 18690 S2 and ORS 18693 S5 of them trapped 100 % and the other (ORS 18691 S5 80 %> of 7-day-old juvenile Meloidogyne mayaguensis within 48h. Optimal growth occured at 25-30°C and at a pH 5.6, but salinity inhibited development. In order to test the ability of fungi to control M. mayaguensis in pots on tomato, the fungus was incorporated into compost blocks or in vermiculite before sowing or subsequent transplanting. In pot experiments both strains reduced nematode populations ans stimulated seedling growth. However, these effects were higher in compost blocks than in vermiculite.

  19. Etude comparative de la rentabilité de deux types d'apiculture au nord ouest du Cameroun

    NARCIS (Netherlands)

    Tsafack Matsop, A.S.; Muluh Achu, G.; Kamajou, F.; Ingram, V.; Vabi Boboh, M.

    2011-01-01

    La présente étude examine la rentabilité financière de l’apiculture au Cameroun. Son objectif global est de comparer la rentabilité des deux types d’apiculture pratiqués au Nord Ouest Cameroun. L’hypothèse globale est qu’il existerait une différence significative en rendement de miel et en bénéfice

  20. Contribution to the study of {beta} disintegration and of nuclear structure using experiments on certain {beta}-{gamma} cascades: 198{sub Au}, 86{sub Rb}, 170{sub Tm}; Contribution a l'etude de la desintegration beta et a l'etude de la structure nucleaire a l'aide d'experiences sur certaines cascades beta-gamma: 198{sub Au}, 86{sub Rb}, 170{sub Tm}

    Energy Technology Data Exchange (ETDEWEB)

    Lachkar, J. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes; Paris-11 Univ., fabulte des Sciences 91 - Orsay (France)

    1969-07-01

    {beta}{gamma} directional angular correlations and shapes of inner beta spectra leading to the first excited level of the final nucleus enable one to determine the nuclear matrix elements typical of the {beta} transition. In the three observed first forbidden cases: {sup 170}Tm, {sup 86}Rb, {sup 198}Au, these matrix elements do not confirm the independent shell model theory. Other hypotheses are then suggested and discussed. (author) [French] Les experiences de correlation angulaire {beta}{gamma} et l'etude du spectre {beta} conduisant au premier niveau excite du noyau final permettent de determiner les elements de matrices nucleaires caracteristiques de cette transition. Dans les trois cas etudies (transitions une fois interdites): {sup 170}Tm, {sup 86}Rb, {sup 198}Au, ces elements de matrices ne peuvent etre retrouves a l'aide du modele en couches et a particules independantes. D'autres hypotheses sont alors emises et discutees. (auteur)

  1. Contribution to the study of {beta} disintegration and of nuclear structure using experiments on certain {beta}-{gamma} cascades: 198{sub Au}, 86{sub Rb}, 170{sub Tm}; Contribution a l'etude de la desintegration beta et a l'etude de la structure nucleaire a l'aide d'experiences sur certaines cascades beta-gamma: 198{sub Au}, 86{sub Rb}, 170{sub Tm}

    Energy Technology Data Exchange (ETDEWEB)

    Lachkar, J [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes; Paris-11 Univ., fabulte des Sciences 91 - Orsay (France)

    1969-07-01

    {beta}{gamma} directional angular correlations and shapes of inner beta spectra leading to the first excited level of the final nucleus enable one to determine the nuclear matrix elements typical of the {beta} transition. In the three observed first forbidden cases: {sup 170}Tm, {sup 86}Rb, {sup 198}Au, these matrix elements do not confirm the independent shell model theory. Other hypotheses are then suggested and discussed. (author) [French] Les experiences de correlation angulaire {beta}{gamma} et l'etude du spectre {beta} conduisant au premier niveau excite du noyau final permettent de determiner les elements de matrices nucleaires caracteristiques de cette transition. Dans les trois cas etudies (transitions une fois interdites): {sup 170}Tm, {sup 86}Rb, {sup 198}Au, ces elements de matrices ne peuvent etre retrouves a l'aide du modele en couches et a particules independantes. D'autres hypotheses sont alors emises et discutees. (auteur)

  2. Contribution to the study of deformed heavy nuclei by means of nuclear reactions; Contribution a l'etude des noyaux lourds deformes au moyen de reactions nucleaires

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-06-01

    The experimental results obtained in the study of the (d,p) reactions, at E{sub d} = 12 MeV, on the three even-even deformed nuclei {sup 170}Yb, {sup 172}Yb and {sup 174}Yb have been analysed in terms of DWBA calculations. The spectroscopic information relative to the odd final nuclei have been compared with the predictions of the collective model and of the Nilsson's model. The effect of various parameters used in the DWBA analysis (form factors, optical wave functions) has been carefully studied. The observed differences between the three final nuclei are qualitatively reproduced in the experimental study of resonances, seen in excitation functions of elastically and inelastically scattered protons on the same target nuclei, and corresponding to analogue states in the three nuclei {sup 171}Lu, {sup 173}Lu and {sup 175}Lu. (author) [French] Les resultats experimentaux de l'etude des reactions (d.p) a E{sub d} = 12 MeV, sur les noyaux deformes pairs-pairs {sup 170}Yb, {sup 172}Yb et {sup 174}Yb ont ete interpretes dans le cadre de l'approximation de Born des ondes deformees. Les informations spectroscopiques relatives aux noyaux impairs finals ont ete comparees aux predictions du modele collectif et du modele de Nilsson, apres avoir examine avec soin l'influence des differents parametres (facteurs de forme, fonctions d'onde 'optiques') utilises lors de l'analyse. Les differences observees entre les trois noyaux finals sont qualitativement reproduites par les resultats experimentaux de l'etude de resonances dans les fonctions d'excitation de diffusion elastique et inelastique de protons sur les memes noyaux-cibles, lors de la recherche d'etats analogues dans les noyaux {sup 171}Lu, {sup 173}Lu et {sup 175}Lu. (auteur)

  3. Study of light fragment production in Au + Au collisions at 150 and 400 A.MeV; Etude de la production de fragments legers dans les collisions Au + Au a 150 et 400 A.Me V

    Energy Technology Data Exchange (ETDEWEB)

    Amouroux, V

    1996-12-17

    We study light fragment production in Au + Au collisions at energies between 150 and 400 A.MeV. Experimental data are extracted from Phase I experiments performed with the FOPI detector at GSI-Darmstadt. We first give centrality criteria and the method used in order to have an evaluation of the impact parameter; that permit comparison between experiment and IQMD or FREESCO models. A first study concerns charge distributions and the reduced variance {gamma}{sub 2}. We observe that the amplitude of the reduced variance decreases rapidly as the centrality of the collision increases; this last point shows that there is no liquid-gas phase transition in central collisions. Such a conclusion agrees with theoretical studies made by the Nantes group concerning fragment formation. A second part concerns a systematic study of differential cross sections of fragment production. We show that IQMD model gives a good qualitative agreement with experimental data; nevertheless, charge distributions are not correctly reproduced by theory. A study of the parameter which fix the width of the Gaussian associated with the nucleons of the interacting system can improve the shape of the charge distributions. Finally, we give at the end of the thesis a systematic presentation of experimental invariant cross sections of fragment production. (author) 80 refs.

  4. Mise au point du rheometre a cisaillement annulaire pour l'etude de rheologie d'un mastic bitumineux avec verre incorpore =

    Science.gov (United States)

    El Mansouri, Souleimane

    Dans le domaine viscoelastique lineaire (VEL, domaine des petites deformations), le comportement thermomecanique du bitume et du mastic bitumineux (melange uniforme de bitume et de fillers) a ete caracterise au Laboratoire des Chaussees et Materiaux Bitumineux (LCMB) de l'Ecole de technologie superieure (ETS) avec l'appui de nos partenaires externes : la Societe des Alcools du Quebec (SAQ) et Eco Entreprises Quebec (EEQ). Les proprietes rheologiques des bitumes et des mastics ont ete mesurees grâce a un nouvel outil d'investigation appele, Rheometre a Cisaillement Annulaire (RCA), sous differentes conditions de chargement. Cet appareil permet non seulement de solliciter des eprouvettes de tailles importantes par rapport a celles utilisees lors des essais classiques, mais aussi d'effectuer des essais en conditions quasi-homogenes, ce qui permet de donner acces a la loi de comportement des materiaux. Les essais sont realises sur une large gamme de temperatures et de frequences (de -15 °C a 45°C et de 0,03Hz a 10 Hz). Cette etude a ete menee principalement pour comparer le comportement d'un bitume avec celui d'un mastic bitumineux dans le domaine des petites deformations. neanmoins, dans une seconde perspective, on s'interesse a l'influence des fillers de verre de post-consommation sur le comportement d'un mastic a faibles niveaux de deformations en comparant l'evolution des modules complexes de cisaillements (G*) d'un mastic avec fillers de verre et un mastic avec fillers conventionnels (calcaire). Enfin, le modele analogique 2S2P1D est utilise pour simuler le comportement viscoelastique lineaire des bitumes et des mastics bitumineux testes lors de la campagne experimentale.

  5. Development of a method for studying non-linear phenomena in plasma; Mise au point d'une methode d'etude des phenomenes non lineaires dans un plasma

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-03-01

    The study of non-linear phenomena resulting from the interaction of powerful electro-magnetic waves with an electron gas is the basis of the p best methods for measuring the frequency of electronic collisions in the ionosphere. In laboratory plasma the appearance of these phenomena is connected with a powerful critical field. Although we have used a relatively low-power electromagnetic source, we have been able to develop a simple hyper-frequency method making it possible to study these phenomena to measure them and to put forward an elementary interpretation. An electromagnetic wave provided by a 1 watt klystron interacts with a HF discharge (25 MHz) in the volume of a TE{sub 111} cavity. The tube containing the discharge and the axis of the cylindrical cavity are co-linear with a magnetic field which can attain a value such that the wave frequency is equal to the gyromagnetic frequency of the electrons. The resonance curve for the cavity, which depends on the electronic density and the frequency of collisions, becomes increasingly dissymmetric as the absorbed power increases and as the gyromagnetic frequency of the electrons approaches that of the incident wave. By studying the resonance, it is possible to calculate the proportionality coefficients relating the density and collision frequency variations with the absorbed power. The experiments were carried out by causing the following to vary separately: the incident UHF power, the initial electronic density, the pressure of the neutral ambient gas, and the axial magnetic field. The variation in the electronic density as a function of the magnetic field for a high UHF power shows a resonance of dissymmetrical form, sometimes with a sharp peak in the neighbourhood of {omega}{sub H}. The possibility of applying these properties to the construction of practical devices, is under consideration. (author) [French] L'etude des phenomenes non lineaires dus a l'interaction d'ondes electro-magnetiques puissantes avec un

  6. les causes de l'abandon de l'etude du français en form deux au kenya

    African Journals Online (AJOL)

    Frederick Iraki

    réserver ou fixer un rendez vous qui n'est pas agréable et facile dans la culture kenyane. L'Ambassade de France au Kenya a aussi été mentionnée, pour souligner qu'elle a arrêté des bourses et des supports linguistiques surtout pour les professeurs de français et les étudiants de français à l'université. Ils pensent que ...

  7. Etude séro-épidémiologique de la leishmaniose canine au centre du Maroc

    Science.gov (United States)

    Fellah, Hajiba; Doughmi, Oursula; Maniar, Saâd; Lalami, Abdelhakim El Ouali

    2014-01-01

    Dans le monde, la leishmaniose viscérale humaine est connue pour avoir comme principale source d'infection les Canidés domestiques et sauvages. Au centre du Maroc, les données épidémiologiques, cliniques et parasitologiques sur la leishmaniose canine, sont quasiment inexistantes. Ce travail traite une étude prospective au cours de laquelle 61 sérums canins ont été analysés par un test rapide et par l'immunofluorescence indirecte. La sensibilité du test rapide par rapport à celle de l'immunofluorescence indirecte (IFI) est de 33,33%. La fréquence de la maladie chez les chiens s’élève à 9,83% (Test Rapide) et 24,59% (IFI). 73,33% des cas canins positifs à la sérologie sont asymptomatiques. Ce sont les jeunes chiens de moins de 5 ans qui sont les plus fréquemment atteints avec une sensibilité de la race Berger Allmand à l'infection. Cette étude a permis de mettre en évidence la présence de chiens leishmaniens (15 chiens séropositifs parmi 61) et de prouver l'existence du réservoir canin. Une stratégie de prévention active doit être mise en place. PMID:25852791

  8. Power Reactor Design at Zero Power; Etudes de Reacteurs de Puissance, au Moyen de Machines de Puissance Zero; Konstruktsiya ehnergeticheskogo reaktora nulevoj moshchnosti; Diseno de Reactores Generadores con Ayuda de Reactores de Potencia Nula

    Energy Technology Data Exchange (ETDEWEB)

    Redman, W. C.; Plumlee, K. E.; Baird, Q. L. [Argonne National Laboratory, Argonne, IL (United States)

    1964-02-15

    reliance placed in the past on exponential and critical systems for fulfilling Argonne's responsibilities in reactor development. An indication of their future role is provided by a brief summary of the current and planned programmes for the existing members of, and anticipated additions to, Argonne's family of operating zero-power reactors. (author) [French] Avec le reacteur de puissance zero du Laboratoire national d'Argonne, on a procede a des etudes de reacteurs tres divers; reacteurs de recherche, generatrices nucleaires, reacteurs pour la propulsion, pour la production de radioisotopes et reacteurs experimentaux; les ensembles associes - exponentiels et critiques non empoisonnes - ont fourni les donnees debase. Afin de rendre compte d'experiences recentes et de montrer quelle masse de renseignements sur la physique des reacteurs on peut obtenir avec des systemes a bas flux, les auteurs exposent les programmes experimentaux ci-apres: 1. Etude des proprietes des elements combustibles en oxydes d'uranium et de thorium, immerges dans l'eau lourde, en s'attachant particulierement aux donnees necessaires pour l'etude d'un deuxieme coeur pour le reacteur experimental a eau bouillante du Laboratoire d'Argonne; 2. Maquette d'un reacteur de recherche a haut flux, qui permettra de verifier les calculs faits au cours de l'etude, de determiner la geometrie optimale et d'estimer l'effet du taux de combustion; 3. Determination des repartitions energetiques et de l'effet de l'immersion des cartouches sur la reactivite pour un reacteur experimental a ebullition et a surchauffe combinees; 4. Etude d'un coeur de reacteur surgenerateur plutonigene a neutrons rapides, alimente en U{sup 235} et refroidi au sodium qui constituerait la charge initiale du Deuxieme reacteur surgenerateur experimental d'Argonne; 5. Etude des caracteristiques d'un reacteur a deux regions, l'une thermique et l'autre rapide, en interaction. Dans l'expose de ces programmes, les auteurs expliquent pourquoi on a

  9. Study of the mechanism of Pb + Au reaction at 29 A.MeV; Etude du mecanisme de la reaction Pb + Au a 29 A.MeV

    Energy Technology Data Exchange (ETDEWEB)

    Aboufirassi, M

    1994-07-01

    The aim of this thesis is to demonstrate the binary character of Pb + Au reaction at 29 A.MeV and to study the decay modes of very excited nuclei produced. The experiment set up was performed at the GANIL in the scattering chamber NAUTILUS. It was composed by multi detectors of fragments (Z {>=}8) and multi detectors of light charged particles. (Z<8). The analysis of events which lead to detection of more then 80 % of both total charge and total parallel momentum proved that two body final state is still present at this incident energy. This mechanism is similar to the mechanism of heavy ion reaction at low bombarding energy. We have shown that complete damping occurred leading to excitation energy as high as 6 Me V/u. The decay modes of deep inelastic products are evaporation residue or binary fission or multifragmentation. Analysing the fission products, we have estimated the aligned spin of deep inelastic products (45 h). Finally, the study of light charged particles detected with fission fragments has demonstrated that these particles are emitted essentially before fission. The temperature value of hot nuclei emitted at foreword angle is deduced of light particle spectra. (author). 59 refs.

  10. Contribution to the study of light nuclei with polarized deuterons; Contribution a l'etude des noyaux legers au moyen de deutons polarises

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-04-15

    We describe roughly the vector and tensor-polarized deuteron source associated with the Saclay fixed energy (22 MeV) cyclotron. This has been used to measure the deuteron asymmetry in d-{alpha} scattering (between 17.7 and 21.4 MeV) and in d-p scattering at 21.7 MeV. Then we develop the formalism of irreducible tensor operators used to describe the polarization of a particle of given spin and we study the helicity formalism used to describe the scattering amplitudes for scattering of deuterons by {alpha} (spin 0) and protons (spin 1/2). We apply the preceding results to the phase shift analysis of scattering cross-sections and: 1) deuteron polarization in d-{alpha} scattering from 10 to 27 MeV from which we obtain indications about the excited states of {sup 6}Li; 2) proton and deuteron polarizations in p-d (or d-p) scattering from 1.5 to 12 MeV so as to get the splitting (due to spin interactions) of P and D waves. (author) [French] On decrit sommairement la source de deutons polarises vectoriellement et tensoriellement associee au cyclotron a energie fixe de Saclay avec laquelle on a mesure l'asymetrie des deutons dans la diffusion d-{alpha} de 17,7 a 21,4 MeV et d-p a 21,7 MeV. Puis or developpe le formalisme des operateurs tensoriels irreductibles utilise pour decrire la polarisation d'une particule de spin quelconque. On etudie ensuite le formalisme de l'helicite dans lequel on etudie la diffusion elastique des deutons diffuses par des particules {alpha} (spin 0) et des protons (spin 1/2). On applique les resultats precedents a l'analyse en dephasages de la section efficace et des polarisations: 1 )des deutons dont la diffusion d-{alpha} de 10 a 27 MeV destinee a donner des indications sur les niveaux excites de {sup 6}Li; 2) des protons et des deutons dans la diffusion p-d de 1,5 a 12 MeV en vue de l'etude de la separation suivant les differentes valeurs du moment total J, des ondes P et D (separation due aux interactions de spin). (auteur)

  11. Investigation of the diffusion {proportional_to} brasses using methods depending on the evaporation or condensation of zinc; Etude de la diffusion dans les laitons {proportional_to} au moyen des methodes d'evaporation ou de condensation du zinc

    Energy Technology Data Exchange (ETDEWEB)

    Accary, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Centre d' Etudes de Chimie Metallurgique du CNRS (France)

    1959-07-01

    Diffusion in {alpha} brasses has been investigated using methods involving the evaporation and the condensation of zinc. Having shown that at sufficiently high temperatures intergranular diffusion has no effect, it was then proved that the rate of evaporation or of condensation can only be defined if the mechanical treatment of the test piece before diffusion, the direction of the diffusion and the nature of the impurities present are also defined. The coefficient of diffusion D is then given by the equation D ({pi}/4t){rho}{sup 2}{sub 0} where t is the duration of the diffusion; {rho}{sub 0} is the extrapolated value of {rho} = ({delta}m)/({delta}C) for a zero value of the variation of concentration ({delta}m in is the change in weight of the test piece per unit surface; {delta}C is the difference between the concentration at the surface and the initial concentration of the test piece). This method has been used to study the effect of the direction of the diffusion on the coefficient of diffusion. The coefficient for diffusion which decreases the concentration of zinc is 5 times greater than that for diffusion which increases the quantity of zinc in the metal; an interpretation of this phenomena based on the mechanism of diffusion vacancies in the structure has been proposed. By means of micrographic investigation and by weighing it has been shown that the presence of certain impurities, such as phosphorous, arsenic, antimony, silicon, and aluminium can result in a marked increase of the rate of diffusion: the effect of these impurities on the coefficient of diffusion has been related to their valency and atomic weight. (author) [French] La diffusion dans les laitons {alpha} a ete etudiee au moyen des methodes d'evaporation et de condensafion du zinc. Apres avoir montre qu'aux temperatures suffisamment elevees, la diffusion intergranulaire ne jouait aucun role, l'auteur a prouve que la vitesse d'evaporation ou de condensation n'est definie que dans la mesure ou

  12. Study of certain random variations in the measurement of low level radioactivities by means of electric circuits (1963); Etude, au moyen de circuits electroniques, de certaines fluctuations aleatoires dans les mesures de radioactivite a bas niveau (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-03-15

    The aim of this work is to find a control method which ensures that there is really a statistical distribution of pulses during the measurement of very low activities. The use of a method based on the distribution of time intervals is examined first, as well as the graphical representation to which it leads. The second method is a study of the distribution of the number of pulses in a given time interval. It makes it possible to use two tests for verifying Gauss's law: Henry's graphical test and the {chi}{sup 2} mathematical test. The electronic devices necessary for these tests have been built; they have made it possible to study the fluctuations in on installation for measuring the natural activity of carbon. (author) [French] Le but de ce travail est de rechercher des methodes de controle qui permettent de s'assurer qu'au cours de mesures de tres faibles activites, on a bien une distribution statistique des impulsions. L'utilisation d'une premiere methode basee sur la distribution des intervalles de temps est d'abord examinee, ainsi que la representation graphique a laquelle elle conduit. La deuxieme methode est une etude de la repartition du nombre d'impulsions pendant un temps determine. Elle permet l'utilisation de 2 tests de verification de la loi de Gauss: le test graphique de Henry et le test mathematique de {chi}{sup 2}. Les dispositifs electroniques necessaires pour l'utilisation de ces tests ont ete realises.; ils ont ensuite permis l'etude des fluctuations dans une installation de mesure d'activite naturelle du carbone. (auteur)

  13. Study of point defects in pure iron by means of electrical resistivity; Etude au moyen de la resistivite electrique des defauts ponctuels dans le fer pur

    Energy Technology Data Exchange (ETDEWEB)

    Minier-Cassayre, C [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-04-01

    In the first part of this work, after having reviewed the production, observation and the annealing of point defects In metals, we resume the present state of research. In the second part, we explain the techniques we have employed to produce point defects at low temperatures: irradiation, quenching and cold-work; and go on to the study of their migration and annealing. The experimental results obtained for pure iron and for iron containing certain impurities are presented in the third part. In the fourth part we suggest a model which explains the different stages of annealing observed, and their properties. We then compare the energies of interaction between point defects with the values deduced from the theory of elasticity. (author) [French] Dans la premiere partie de cette etude, apres avoir passe en revue la production, l'observation et les modes de guerison des defauts ponctuels dans les metaux, nous exposons l'etat actuel des recherches. La seconde partie est consacree aux techniques que nous avons employees pour produire des defauts ponctuels a basse temperature: irradiations, trempe et ecrouissage puis a l'etude de leur migration et de leur guerison. Les resultats experimentaux obtenus dans le fer pur et le fer contenant certaines impuretes sont presentes dans le troisieme chapitre. Nous proposons ensuite un modele qui explique les differents stades de guerison observes et leurs nombreuses proprietes: nous comparons les energies d'interaction entre defauts ponctuels aux valeurs que l'on pourrait deduire d'un modele elastique. (auteur)

  14. The study by means of a photomultiplier of the scintillations produced by {alpha} particles striking a zinc sulphide screen; Etude, au photomultiplicateur, des scintillations produites par les particules {alpha} dans un ecran de sulfure de zinc. Application a la numeration precise des particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-06-15

    The object of the study is the accurate counting of {alpha} particles by p-m. detection of their scintillations upon impact with a zinc sulphide screen. The main advantage of the method is the extreme simplicity of the electronics used: the possibility of obtaining a utilizable pulse from the p-m. (EMI5311) without any amplification, and in linear response, is demonstrated. The scintillation produced by an impact on Zn-S has also been studied experimentally. The decrease of light intensity in relation to time may be interpreted by the exponential relation: I = I{sub 0} exp (-t / {tau}) whereby {tau} = (39 {+-} 0,1) 10{sup -6} s. The relation between scintillation intensity and remaining trajectory after travel through a given air-space has also been determined. Possible suitable applications of this method of {alpha} counting are those where good stability and low background are necessary. Results stated bear on air contamination studies, isotopic composition variation measurement of uranium, bismuth content measurement in alloys by irradiation of specimens in a thermal neutron flux and {alpha} count on the Po formed. (author) [French] Ce travail est consacre a l'etude de la numeration precise des particules {alpha} par detection au photomultiplicateur des scintillations produites par ces particules dans un ecran de sulfure de zinc. Le principal avantage de cette methode reside dans l'extreme simplicite de l'appareillage electronique; il est en effet montre qu'il est possible, tout en convoyant une reponse lineaire, d'obtenir du photomultiplicateur (EMI5311) un signal electrique utilisable sans aucune amplification. La scintillation produite par l'impact des particules {alpha} sur un ecran de Zn-S est etudiee experimentalement. La decroissance de l'intensite lumineuse en fonction du temps est interpretable par la relation exponentielle I = I{sub 0} exp (-t / {tau}) avec {tau} = (39 {+-} 0,1) 10{sup -6} s. La relation entre l'intensite de la scintillation et le

  15. Study by {alpha}-particle scattering, of the collective states of closed shell nuclei with 28 neutrons, 28 and 50 protons; Etude des etats a caractere collectif des noyaux au voisinage des couches fermees par diffusion inelastique des particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-01-01

    This report gives the results from a systematic study by 44 MeV {alpha} particle scattering on the collective states of closed shell nuclei with 28 neutrons, 28 and 50 protons especially in the energy region corresponding to the two phonon vibrational triplet. The nuclei studied are: {sup 46}Ti, {sup 48}Ti, {sup 50}Ti, {sup 52}Cr, {sup 54}Fe, {sup 56}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 62}Ni, {sup 64}Ni, {sup 112}Sn, {sup 114}Sn, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, {sup 122}Sn and {sup 124}Sn. The theoretical analysis has been made with the Austern and Blair model using a phase shift analysis of the elastic scattering. Deformation lengths {delta}{sub I} = {beta}{sub I}R and transition probabilities obtained are compared with several experimental and theoretical data. (author) [French] Ce rapport donne les resultats d'une etude systematique par diffusion de particules {alpha} de 44 MeV des etats collectifs des noyaux au voisinage des couches fermees a 28 neutrons et 28 et 50 protons, specialement dans la region correspondant au triplet vibrationnel a deux phonons. Les noyaux etudies sont: {sup 46}Ti, {sup 48}Ti, {sup 50}Ti, {sup 52}Cr, {sup 54}Fe, {sup 56}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 62}Ni, {sup 64}Ni, {sup 112}Sn, {sup 114}Sn, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, {sup 122}Sn et {sup 124}Sn. L'analyse theorique a ete faite a l'aide du modele de Austern et Blair utilisant une analyse en dephasages de la diffusion elastique. Les longueurs de deformation {delta}I = {beta}{sub I}R obtenues pour chaque niveau sont comparees a plusieurs donnees experimentales et theoriques. (auteur)

  16. Feasibility study for the installation of a small hydro electric power plant; Etude de faisabilite. Petite centrale hydro-electrique au lieu dit 'Sous les Roches' a Sonceboz

    Energy Technology Data Exchange (ETDEWEB)

    Tissot, N. [MHyLab, Mini-Hydraulics Laboratory, Montcherand (Switzerland); Hausmann, H. [Hans Hausmann, Bevilard (Switzerland)

    2003-07-01

    This report for the Swiss Federal Office of Energy presents a technical, economical and ecological analysis of the feasibility of a small hydroelectric power plant at Sonceboz, in the Swiss Jura mountains. The power of the planed plant would typically be 500 kW for a water head of about 10 m. The study shows that, compared to one single turbine, a pair of Kaplan type turbines would be operational over a larger range of the river's water flow rate. This solution would be a little bit more costly but offer more flexibility for maintenance. Two maximum water flow rates are considered, 4.5 and 6 m{sup 3}/s respectively. According to the economical study, done with current electric kWh prices, both configurations are viable while the largest flow rate leads to a larger profit. The report is rounded up by a sensitivity analysis considering variations in annual power generation, electro-mechanical and construction cost as well as turbine efficiency. It indicates that this last factor could be crucial for the overall profitability. [French] Ce rapport est le resultat detaille de l'analyse technico-economique et ecologique de faisabilite de la realisation d'une petite centrale hydroelectrique basse chute qui pourrait exploiter une denivellation d'environ 10 m pour une puissance de l'ordre de 500 kW pres de Sonceboz dans le Jura suisse. L'etude montre que le couplage de deux turbines Kaplan offrirait une possibilite de fonctionnement sur une plus grande plage de flux ainsi qu'une plus grande flexibilite de maintenance, ceci pour un cout legerement superieur a l'option a une seule turbine. Les debits de 4.5 et 6 m{sup 3}/s sont consideres. L'etude economique montre que le debit de 6 m{sup 3}/s est plus rentable au prix de vente actuel du kWh. L'article se termine par une analyse de sensibilite sur les incertitudes concernant la production annuelle, les prix de l'electromecanique et du genie civil et le rendement des

  17. Treatment of Radioactive Effluents at the Saclay Nuclear Research Centre; Traitement des Effluents Radioactifs au Centre d'Etudes Nucleaires de Saclay; 041e 0414 ; Tratamiento de los Efluentes Radiactivos en el Centro de Energia Nuclear de Saclay

    Energy Technology Data Exchange (ETDEWEB)

    Wormser, G. [Service de Controle des Radiations et de Genie Radioactif, Commissariat a l' Energie Atomique, Saclay (France)

    1960-07-01

    The Report Gives The Account Of Four Years' Experience In Operating The Treatment Plant For Effluents From The Saclay Nuclear Research Centre. It Contains Data Relating To The Origin, Volume And Treatment Of Waste. (author) [French] Ce rapport presente un bilan d'exploitation de l'installation de traitement des effluents du Centre d'etudes nucleaires de Saclay depuis quatre ans. On donne des chiffres concernant l'origine des residus, leur volume, leur traitement. (author) [Spanish] El autor hace un balance de explotacion de la instalacion de tratamiento de efluentes del centro de Saclay desde hace cuatro anos, dando las cifras correspondientes al origen de los residuos, a su volumen y a su tratamiento. (author) [Russian] V jetom dokumente podvoditsja itog chetyrehletnej jekspluatacii ustanovki po obrabotke zhidkih othotov v Centre jadernyh issledovanij v Sakle. V doklade privodjatsja dannye o proishozhdenii othodov, jh ob'eme i obrabotke. (author)

  18. Ensembles de donnees nationales : sources d'information sur la garde des enfants au Canada

    OpenAIRE

    Forer, Barry; Hertzman, Clyde; Kohen, Dafna

    2006-01-01

    La presente etude fournit une description des differents ensembles de donnees canadiennes qui pourraient etre utilises pour examiner des questions relatives au recours aux services de garde. Les ensembles de donnees nationales qui traitent des tendances de l'emploi, de l'emploi du temps, des revenus familiaux, du soutien social ainsi que des mesures de la sante des enfants, des adolescents et des adultes ont ete inclus. On a conclu que de nombreuses questions demeurent sans reponse en ce qui ...

  19. Contribution to the study of low fragments correlations during Au + Au collisions at 150 and 400 A.MeV; Contribution a l`etude des correlations entre fragments legers dans les collisions Au+Au a 150 et 400 A.MeV

    Energy Technology Data Exchange (ETDEWEB)

    Montbel, I.

    1994-06-01

    The study of fragment-fragment correlations at small relative momenta can give informations on the space-time extend of the emitting source, and on the nuclear density, which is one of the variables used in the equation of state. This analysis shows the experimental results obtained with the FOPI detector at GSI-Darmstadt, for Au + Au central collisions at 150 and 400 A.MeV. These results are the first studies at such high energies and for heavy systems. Two fragments correlation functions are compared with theoretical calculations of D.H. Boal, including the size of the source as a parameter. We must take into account effects of experimental biases (namely the relative momentum resolution) on the theoretical correlation function, in order to make a comparison with experimental results. The extracted experimental radii correspond to the final phase of the expansion, and the obtained densities are smaller that normal density of nuclear matter. In the final state of the interaction, intermediate mass fragments and their excited states are observed. We note a shift of these excited states at 400 A.MeV, which can be explained by the detector effects. We observe a weak sensibility of the source size versus the centrality of the collision. That can be explained either by a mixing of sources, or by the observation of a source at the end of expansion whose the radius is quite independent of the initial centrality. Energetic particles correspond to smaller size of the source, which can be explained as a higher compression, or as a different stage of the collision. We give some prospectives for the future experiments at GSI-Darmstadt. (author). 117 refs.

  20. Contribution to the study of the biological properties of compounds labeled with radio-chromium {sup 51}Cr; Contribution a l'etude des proprietes biologiques des composes marques au radiochrome {sup 51}Cr

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-15

    Among the radioisotopes commonly used in biology and medicine which are controlled Individually in the Radioelement Departement of the Saclay Nuclear Research Centre before being sent to the users, the author has chosen chromium 51 incorporated in inorganic salts or in organic substrates for a study of the biological properties of the compounds. In the first part, he has compared the pathways followed by the radioactive sodium chromate and chromic chloride mixed with blood or given to the whole animal, the object being to determine whether a reduction of hexavalent chromium occurs, both in vitro and in vivo. In the second part, the author has tried to show the validity of using, various substrates labeled with chromium 51, red cells, haemoglobin, plasma proteins and cytochrome c. The results obtained have contributed to underline the interest of using such compounds for biological applications. (author) [French] Parmi les radioisotopes d'utilisation courants en biologie et en medecine qui sont l'objet d'un controle particulier dans le Departement des Radioelements du Centre d'Etudes Nucleaires de Saclay avant leur diffusion aux utilisateurs, l'auteur a choisi le chrome 51 incorpore a des sels mineraux ou a des substrats organiques, afin d'en etudier les proprietes biologiques. Dans la premiere partie, il a compare le sort du chromate de sodium et du chlorure chromique radioactifs melanges a du sang ou administres a l'animal entier en s'efforcant de mettre en evidence une reduction du chrome hexavalent aussi bien in vitro qu'in vivo. Dans la deuxieme partie, il a cherche a etablir la validite de l'emploi de differents substrats marques au chrome 51, l'hematie, l'hemoglobine, les proteines plasmatiques et le cytochrome c. Les resultats obtenus ont permis de souligner le reel interet des applications biologiques des composes marques par le radioisotope. (auteur)

  1. Contribution to the study of the biological properties of compounds labeled with radio-chromium {sup 51}Cr; Contribution a l'etude des proprietes biologiques des composes marques au radiochrome {sup 51}Cr

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-15

    Among the radioisotopes commonly used in biology and medicine which are controlled Individually in the Radioelement Departement of the Saclay Nuclear Research Centre before being sent to the users, the author has chosen chromium 51 incorporated in inorganic salts or in organic substrates for a study of the biological properties of the compounds. In the first part, he has compared the pathways followed by the radioactive sodium chromate and chromic chloride mixed with blood or given to the whole animal, the object being to determine whether a reduction of hexavalent chromium occurs, both in vitro and in vivo. In the second part, the author has tried to show the validity of using, various substrates labeled with chromium 51, red cells, haemoglobin, plasma proteins and cytochrome c. The results obtained have contributed to underline the interest of using such compounds for biological applications. (author) [French] Parmi les radioisotopes d'utilisation courants en biologie et en medecine qui sont l'objet d'un controle particulier dans le Departement des Radioelements du Centre d'Etudes Nucleaires de Saclay avant leur diffusion aux utilisateurs, l'auteur a choisi le chrome 51 incorpore a des sels mineraux ou a des substrats organiques, afin d'en etudier les proprietes biologiques. Dans la premiere partie, il a compare le sort du chromate de sodium et du chlorure chromique radioactifs melanges a du sang ou administres a l'animal entier en s'efforcant de mettre en evidence une reduction du chrome hexavalent aussi bien in vitro qu'in vivo. Dans la deuxieme partie, il a cherche a etablir la validite de l'emploi de differents substrats marques au chrome 51, l'hematie, l'hemoglobine, les proteines plasmatiques et le cytochrome c. Les resultats obtenus ont permis de souligner le reel interet des applications biologiques des composes marques par le radioisotope. (auteur)

  2. etude de la résistance au flétrissement bactérien de lignées inter

    African Journals Online (AJOL)

    Administrator

    4p. Mew, T. W., Vera Cruz, C. M. and Reyes, R. C.. 1992. Interaction of Xanthomonas campestris pv. oryzae and a resistance Rice Cultivar. Phytopathology 72: 786-789. Ouedraogo, S. L. Somda, I. Boro, F. et Seré, Y. 2004 Détection et caractérisation des bactéries phytopathogènes transmises par les semences du riz au ...

  3. Fundamental study of ionization and dissociation processes caused by electron impact in aromatic molecules; application of the quasi-equilibrium theory to phenanthrene and to methylphenanthrenes; Etudes fondamentales des processus d'ionisation et de dissociation des molecules aromatiques par impact electronique et application de la theorie du quasi-equilibre au phenanthrene et aux methyl-phenanthrenes

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    behaviour under ionizing radiations of the studied compounds. (author) [French] La theorie du quasi-equilibre n'a ete appliquee jusqu'a present qu'a la seule famille des hydrocarbures aliphatiques en chaine droite. Nous avons donc essaye de l'etendre au phenanthrene et au methyl-phenantrene, c'est-a-dire, d'une part a des molecules aromatiques et d'autre part a des molecules ayant un tres grand nombre de degres de liberte. Dans une premiere partie nous avons tente d'interpreter de facon methodique les processus d'ionisation et de dissociation des molecules phenanthreniques. Cette premiere etude experimentale du comportement des composes sous impact electronique, et son interpretation, nous ont fourni de precieux renseignements sur de profonds changements de structure des ions moleculaires et fragmentaires, voire d'excitation des molecules etudiees. L'etude approfondie des pics metastables a ensuite confirme les processus de dissociation precedents, tout en precisant certaines grandeurs thermodynamiques relatives aux reactions de decomposition. Etudes des processus d'ionisation, puis de dissociation, et enfin des pics metastables, constituent les trois temps d'une methode generale d'interpretation de la fragmentation en spectrometrie de masse. Pour donner a cette methode son assise theorique nous avons ete amenes a elaborer les diagrammes moleculaires de chacun des composes etudies, montrant ainsi l'aide efficace que peut presenter la Mecanique Quantique pour l'etude des etats excites et ionises. Dans une seconde partie, nous avons calcule les spectres de masse du phenanthrene et des methyl-phenanthrenes a partir des expressions des constantes de reaction donnees par ROSENSTOCK. Pour ce faire, nous avons propose de nouvelles methodes de calcul des facteurs de frequence, tant pour les molecules aliphatiques que les aromatiques. Si le bon accord generalement observe entre le calcul et l'experience ne peut etre attribue a coup sur a l'exactitude de la theorie, il n'en demontre

  4. 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)

  5. Exclusive study of Ni+Ni and Ni+Au central collisions: phase coexistence and spinodal decomposition; Etude exclusive des collisions centrales Ni+Ni et Ni+Au: coexistence de phase et decomposition spinodale

    Energy Technology Data Exchange (ETDEWEB)

    Guiot, B

    2002-12-01

    The INDRA multidetector allowed us to study the Ni+Ni collisions at 32A MeV and the Ni+Au collisions at 52,4 MeV. Central collisions leading to 'quasi-fused' systems were isolated using multidimensional analysis techniques: the Discriminant Analysis and the Principal Component Analysis. Comparison with a statistical model shows that the selected events are compatible with thermodynamical equilibrium. The average thermal excitation energy is 5A MeV for both systems. Calculations of heat capacities show that the deexcitation of the hot sources are akin to a liquid-gas phase transition of nuclear matter. Indeed heat capacities exhibit a negative branch as expected for a phase transition of a finite system. The dynamics of this phase transition has been investigated by applying the charge correlation method. An enhanced production of events with equal-sized fragments has been evidenced for Ni+Au at 52A MeV. No signal was found for Ni+Ni at 32A MeV. Finally this method was improved by taking into account the total charge conservation. The signal is seen more clearly for Ni+Au at 52A MeV, but is ambiguous for Ni+Ni at 32A MeV. The path followed in the state diagram, or the involved time scales, seem to be different for these systems. (authors)

  6. Etude de la cristallisation du bicarbonate de sodium raffiné:contribution au modèle des colonnes à bulles

    OpenAIRE

    Gutierrez, Vanessa

    2010-01-01

    La société Solvay est le plus grand producteur de bicarbonate de sodium raffiné au monde. Le NaHCO3 est un des produits parmi les plus connus et utilisés. Sa production a lieu dans des colonnes à bulles de volumes très importants. La production du bicarbonate de sodium raffiné dans ces réacteurs peut se résumer par la réaction entre une solution saturée de carbonate de sodium (Na2CO3) et le CO2(gaz) Cette production implique la connaissance et le contrôle des réacteurs de type triphasique. E...

  7. A study by internal friction of defects produced in iron and nickel irradiated at very low temperatures; Etude au moyen du frottement interne des defauts crees par irradiation a tres basse temperature dans le fer et le nickel

    Energy Technology Data Exchange (ETDEWEB)

    Keating-Hart, G de [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    This work represents a contribution to the study of point defects in metals. After a brief review of the theory of internal friction we will discuss some technical innovations aimed at increasing the flexibility of the apparatus at our disposal. These innovations have allowed us to extend our range of measurements down to 20 deg. K. We will then discuss our experimental results. Firstly, we describe preliminary experiments on electron irradiated iron and the evidence for a laminar structure. Secondly, we present and account of the first measurements on nickel after neutron irradiation at 27 deg. K. We will compare the results with those obtained by other methods in this laboratory. Essentially we have observed transitory peaks at low temperature due to close Frenkel pairs and we have noticed the absence of a peak which would correspond to the magnetic after effect band of stage I{sub E}. An attempt is made to explain the disappearance of the observed peaks upon the application of an internal saturating magnetic field. (author) [French] Ce memoire constitue une contribution a l'etude des defauts ponctuels dans les metaux. Apres un bref apercu theorique sur le frottement interne, nous presenterons quelques realisations techniques destinees a accroitre les possibilites des instruments qui nous ont ete confies. Ces dernieres nous ont permis d'etendre la gamme des mesures jusqu'a 20 deg. K. Nous parlerons ensuite de nos resultats experimentaux. En premier lieu, ceux obtenus au cours de premieres experiences, sur le fer irradie aux electrons mettent en evidence des structures de laminage. En second lieu, nous exposerons les premieres mesures realisees sur du nickel irradie aux neutrons; nous comparerons ces resultats avec ceux obtenus par d'autres moyens experimentaux dans le laboratoire. Nous avons observe essentiellement des pics fugitifs a basse temperature dus aux paires proches de Frenckel et nous avons constate l'absence d'un pic correspondant a la bande de tramage

  8. Silicon P.I.N. Junctions used for studies of radiation damage; Etude de l'irradiation aux neutrons rapides du silicium au moyen de jonctions P.I.N

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [French] L'irradiation de structures P.I.N. etait faite dans le but d'etudier principalement la mise au point d'un dosimetre a ''radiation damage'' et aussi pour etudier plus profondement le silicium lui-meme. On sait que le taux de recombinaison electrons-trous est une fonction lineaire du taux de defauts introduits par irradiation aux neutrons. Deux methodes ont ete utilisees pour atteindre ce taux de recombinaison: mesures de la caracteristique directe, mesures du temps de retournement. Pour expliquer de quelle facon ces parametres dependent du taux de recombinaison. Nous avons donne une theorie de la jonction P.I.N. Nous avons aussi donne l'allure des variations du temps de vie des porteurs en fonction de la temperature. Nous avons d'autre part effectue des recuits entre 70 et 700 K, domaine dans lequel nous avons trouve cinq etapes de ''guerison'' avec les energies d'activation correspondantes. En application de ces etudes nous avons mis ou point un dosimetre a ''radiation damage'' avec lequel nous avons effectue des

  9. Silicon P.I.N. Junctions used for studies of radiation damage; Etude de l'irradiation aux neutrons rapides du silicium au moyen de jonctions P.I.N

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [French] L'irradiation de structures P.I.N. etait faite dans le but d'etudier principalement la mise au point d'un dosimetre a ''radiation damage'' et aussi pour etudier plus profondement le silicium lui-meme. On sait que le taux de recombinaison electrons-trous est une fonction lineaire du taux de defauts introduits par irradiation aux neutrons. Deux methodes ont ete utilisees pour atteindre ce taux de recombinaison: mesures de la caracteristique directe, mesures du temps de retournement. Pour expliquer de quelle facon ces parametres dependent du taux de recombinaison. Nous avons donne une theorie de la jonction P.I.N. Nous avons aussi donne l'allure des variations du temps de vie des porteurs en fonction de la temperature. Nous avons d'autre part effectue des recuits entre 70 et 700 K, domaine dans lequel nous avons trouve cinq etapes de ''guerison'' avec les energies d'activation correspondantes. En application de ces etudes nous avons mis ou point un

  10. Contribution to the study of stimulated emission in neodymium-doped glass; Contribution a l'etude de l'emission stimulee dans le verre dope au neodyme

    Energy Technology Data Exchange (ETDEWEB)

    Jego, J M [Commissariat a l' Energie Atomique, Limeil-Brevannes (France). Centre d' Etudes; Faculte des Sciences de Rennes, 35 (France)

    1969-07-01

    In 1917, Einstein discovered the existence of the stimulated emission of electromagnetic waves by atoms. It is caused by the presence of radiating energy of suitable frequency in a material which is in a non equilibrium state. This discovery held the germ of the idea for the fabrication of generators and waves amplifiers for very short, almost monochromatic wavelengths. forty years elapsed however before these were produced for the first time. A maser operating in the field of micrometric waves appeared in 1954. In the optical field, the first 'Laser' was built by MAIMAN in 1960. The active atom was chromium situated in an alumina matrix (ruby). The fluorescent single crystal was placed between two reflectors which maintained in the medium a provoked inversion of the population until the emission conditions were attained. The laser effect has made it possible to produce several hundred line generators covering the optical range for both gaseous and liquid or solid media. Amongst the latter, neodymium has a transition between the 4 F{sub 3/2} and the 4 I{sub 11/2} levels which has made it possible to obtain very high power lasers. A study has been made during the present work of the conditions in which a pulse can be formed, and of its amplification in neodymium-doped glass. By making accurate measurements of the various yields involved in this process, it has been possible to obtain the value for the population inversion obtained in the medium, and to make a detailed study of stimulated emission in neodymium. (author) [French] En 1917, Einstein annonce l'existence de l'emission stimulee d'ondes electromagnetiques par les atomes. Elle est provoquee par la presence d'energie rayonnante de frequence convenable au sein d'un milieu materiel hors equilibre. Cette decouverte contenait en germe la possibilite de realiser des generateurs puis des amplificateurs d'ondes de tres courtes longueurs d'onde quasi-monochromatiques. Il faut attendre cependant quelques quarante

  11. Etude de l'anémie chez les enfants séropositifs au VIH naïfs au traitement antirétroviral à Lubumbashi, République Démocratique du Congo

    Science.gov (United States)

    Mwadianvita, Costa Kazadi; Ilunga, Eric Kasamba; Djouma, Jackson; Wembonyama, Cecile Watu; Mutomb, Florence Mujing A; Ekwalanga, Michel Balaka; Kabongo, Joe; Mundongo, Henri; Mupoya, Kalombo; Wembonyama, Stanis; Kalenga Mwenze, Prosper; Nkoy, Albert Mwembo-Tambwe A

    2014-01-01

    Introduction Beaucoup d'enfants infectés par le VIH arrivent à la consultation dans un état d'anémie. Notre objectif était d’évaluer la prévalence et le typage de l'anémie chez ces enfants. Méthodes C'est une étude transversale réalisée dans 3 centres de prise en charge des Personnes Vivant avec le VIH à Lubumbashi de Mai 2010 à Mai 2011. La population d’étude était de 152 enfants, âgés de 6 à 180 mois, naïfs au traitement antirétroviral. Les statistiques descriptives usuelles ont été utilisées. Résultats La prévalence globale de l'anémie (définie comme l'hémoglobine < 11g/dl) était de 69,1% (n=105) et 11,4% avaient une anémie sévère (Hg < 7,0 g/dl). Parmi eux, 16% ont été transfusés au moins 1 fois. L'anémie sévère était positivement associée au stade clinique de la maladie (p=0,02). L'anémie microcytaire était majoritaire dans les deux tranches d’âge. Elle était plus hypochrome chez les enfants en âge préscolaire soit 9,5% et plus normochrome en âge scolaire soit 15,2%. L'anémie normocytaire était plus normochrome dans les deux tranches d’âge soit 12,4% en âge préscolaire et 6,7% en âge scolaire. L'anémie macrocytaire était rare. Conclusion Environ sept enfants sur dix, âgés de moins de 15 ans infectés par le VIH naïfs au traitement antirétroviral dans notre milieu sont anémiques. L'anémie est corrélée à la sévérité de la maladie. Il est important d'associer une prise en charge nutritionnelle et corriger l'anémie avant une trithérapie antirétrovirale. PMID:25018796

  12. Study of the heavy ions (Au+Au at 150 AMeV) collisions with the FOPI detector. Comparison with the Landau-Vlasov model; Etude des collisions d`ions lourds AU+AU a 150 A.MeV avec le detecteur FOPI. Comparaison avec le modele de Landau-Vlasov

    Energy Technology Data Exchange (ETDEWEB)

    Boussange, S

    1995-09-15

    In this thesis, heavy ions (Au+Au) collisions experiments are made at 150 AMeV.In the first part, a general study of the nuclear matter equation is presented. Then the used Landau-Vlasov theoretical model is describe. The third part presents the FOPI experience and the details of how to obtain this theoretical predictions (filter, cuts, corrections, possible centrality selections).At the end, experimental results and comparisons with the Landau-Vlasov model are presented. (TEC). 105 refs., 96 figs., 14 tabs.

  13. Folds and Etudes

    Science.gov (United States)

    Bean, Robert

    2007-01-01

    In this article, the author talks about "Folds" and "Etudes" which are images derived from anonymous typing exercises that he found in a used copy of "Touch Typing Made Simple". "Etudes" refers to the musical tradition of studies for a solo instrument, which is a typewriter. Typing exercises are repetitive attempts to type words and phrases…

  14. The atomic energy course of the 'Institut National des Sciences et Techniques nucleaires' at the centre d'Etudes Nucleaires at Saclay; L'enseignement de genie atomique de l'Institut national des Sciences et Techniques nucleaires au Centre d'Etudes nucleaires de Saclay

    Energy Technology Data Exchange (ETDEWEB)

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

    1958-07-01

    foreign students. 8- Annexe: list of courses, practical work, pile projects drawn up by the 1957 students. (author)Fren. [French] 1- Les raisons de sa creation. L'electricite de France et l'industrie interessee par le developpement de l'Energie atomique ont demande au Commissariat a l'Energie atomique de former des ingenieurs capables d'etudier des projets de piles et de diriger leur construction. 2- Recrutement et Droits d'inscription. Les demandes d'inscription ont toujours depasse les possibilites. Cette annee, les cours sont suivis par 74 eleves permanents, dont 20 etrangers, et une centaine d'auditeurs libres. Tous les elevont deja ingenieurs ou nantis de grades universitaires eleves. Droit d'inscription: 250 000 F pour les eleves, 125 000 F pour les auditeurs. 3- Organisation de l'Enseignement. II comprend deux options: physique et chimie et dans chaque option: une centaine de conferences, une trentaine de travaux pratiques, des stages dans les services, l'etude d'un projet de reacteur par un groupe de 4 ou 5 eleves. L'ensemble occupe l'annee universitaire du 1 novembre au 14 juillet. 4- Sanction. Un examen final combinant les notes de deux epreuves theoriques, des travaux pratiques, du stage, et du projet conduit a un diplome d'ingenieur en genie atomique. Il n'est pas cree en realite de nouveaux ingenieurs; une mention nouvelle est seulement ajoutee a un diplome deja acquis. Les resultats ont toujours ete excellents. Le pourcentage des echecs est tres faible. 5- Placement des Diplomes. Ils reviennent tous dans leurs industries d'origine qui ont paye leurs salaires et les droits d'inscription en se privant de leurs services pendant les neuf mois de duree des cours. 6- Creations analogues. Un cours analogue a ete cree au Centre d'Etudes Nucleaires de Grenoble. Tandis que celui de SACLAY s'adresse plus specialement aux ingenieurs deja en fonctions, celui de Grenoble est, en principe, destine aux jeunes ingenieurs sortant des ecoles. 7- Conclusion. L

  15. 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

  16. Low-energy electron observation of graphite and molybdenite crystals. Application to the study of graphite oxidation; Observation au moyen d'electrons de faible energie de cristaux de graphite et de molybdenite. Application a l'etude de l'oxydation du graphite

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    The LEED study of cleaved (0001) faces of crystals having a layered structure allowed to investigate flakes free of steps on graphite and molybdenite, to show twinning on natural graphite. By intensity measurements and computation in the case of a kinematical approximation it has been possible to determine an inner potential of 19 eV for graphite and to identify the direction of the Mo-S bond of the surface layer of molybdenite. The oxidation of graphite has been studied by observing changes, in symmetry of the diffraction patterns and by mass spectrometry of the gases evolved during the oxidation. No surface compounds have been detected and the carbon layers appeared to be peeled off one after the other. The oxidation took place at temperatures higher than 520 C under an oxygen pressure of 10{sup -5} torr. (author) [French] L'etude par diffraction des electrons lents des faces (0001) de cristaux ayant une structure en feuillet a permis de mettre en evidence des plages sans gradins sur des clivages de graphite et de molybdenite caracterisees par la symetrie ternaire des diagrammes, de montrer l'existence de macles sur des cristaux de graphite naturel. Un calcul utilisant une approximation cinematique a ete applique aux intensites mesurees des taches de diffraction; il a ete ainsi possible de determiner un potentiel interne de 19 eV pour le graphite et de preciser la direction de la liaison Mo-S du feuillet superficiel de la molybdenite. L'oxydation du graphite a ete etudiee en mettant en relation des changements de symetrie des diagrammes de diffraction avec l'analyse des gaz provenant de la reaction carbone-oxygene. Il a ete montre qu'il n'y avait pas formation de composes de surface et que les couches de carbone etaient enlevees les unes apres les autres. L'oxydation a ete observee sous une pression d'oxygene de 10{sup -5} torr au-dessus de 520 C. (auteur)

  17. Etude comparative de l'irrigation au goutte-à-goutte et à la raie sur une culture de pomme de terre de saison

    Directory of Open Access Journals (Sweden)

    Boujelben, A.

    2001-01-01

    Full Text Available Comparative Study of the Drip and Furrow Irrigation on Seasonable Potato Crop. Under semi-arid climate conditions, use of furrow irrigation for potato is relatively low when compared to drip irrigation. An experimental trial was carried out at the Agricultural Research Station at Chott-Mariem located in the Center East of Tunisia. A drip irrigation system with three amounts (D, 0.75D and 0.5D was compared to blocked furrows (D on potato. The drip irrigation system (D = 210 mm produced best results for dry and fresh matter production in leaves and stems, and in tubers, percentage cover of soil and plant height. Lower amounts of water applied (0.75D and 0.5D with drip irrigation gives similar results to those obtained with furrow irrigation (D.

  18. Preparation and physico-chemical study of nitroxide radicals. Isotopic marking with carbon 13 and deuterium; Preparations et etudes physico-chimiques de radicaux nitroxydes. Marquage isotopique au carbone 13 et au deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Chapelet-Letourneux, G [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-07-01

    stables ou instables facilement observables par RPE. Enfin, dans le but d'obtenir des valeurs sures de couplages entre l'electron libre d'un nitroxyde et le carbone 13, de tels radicaux marques au {sup 13}C en {alpha} et en {beta} de la fonction nitroxyde, ont ete prepares. Le couplage avec un carbone 13 {alpha} est negatif et semble ne pas varier avec la densite de spin portee par l'azote. L'interaction avec des noyaux en {beta} de l'azote depend de la nature des substituants: les deux protons du benzyle ont un ecart hyperfin a{sub H} toujours inferieur a celui de l'ethyle. Par contre, le couplage du {sup 13}C est plus grand dans le premier cas. Les conformations couramment adoptees pour des composes carbonyles ne peuvent rendre compte de la valeur observee pour les couplages en {beta}. (auteur)

  19. Experimental study of Au+Au collisions at E/A=150 and 400 MeV: comparison with the GQMD-matrix model; Etude experimentale des collisions Au+Au a E/A=150 et 400 MeV: comparaison avec le modele matrice-GQMD

    Energy Technology Data Exchange (ETDEWEB)

    Ramillien, V

    1995-07-01

    We present new experimental data obtained with the FOPI detector at the SIS Heavy ions accelerator (Darmstadt, Germany), for the Au + Au heavy ion collisions at 150 and 400 A.MeV incident energy. The sideward flow, determined form the method of Danielewicz without reaction plane reconstruction, and the nuclear stopping are studied as a function of the centrality of the collisions and as a function of the fragment charge. In order to study the nuclear in-medium effects, which act on the N-N cross-sections and potential and hence on experimental observables like the nuclear matter flow and stopping, these results are compared with the predictions of two different QMD versions. The first one (GQMD) offers a fully microscopic calculation of the cross-sections and potential in the G-matrix formalism and naturally includes the in-medium effects. This version is for the first time confronted to experiment. The second one (IQMD) uses a standard Skyrme potential plus a momentum dependent term in order to mimic the in-medium effects. We find that the experimental stopping is overestimated for 30-40% in the models IQMD and GQMD. Concerning the flow, we find that the momentum dependence of the potential in GQMD is somewhat stronger as can be seen for the more peripheral events and fits better the data in this case. On the other hand, the model GQMD clearly lacks of density dependence to reproduce the more central events. (author). 52 refs., 57 figs., 11 tabs.

  20. Etude d’un phénomène de discrimination esthétique : la « naquez » au Mexique

    Directory of Open Access Journals (Sweden)

    Philippe Schaffhauser

    2008-06-01

    Full Text Available Considérant, comme le laisse entendre le second Wittgenstein des Investigations, que les mots sont doués d’effets tangibles, cet article a pour objectif de présenter et d’examiner de près la catégorie culturelle mexicaine de la naquez (ou naquisa : équivalent français du concept vernaculaire de plouc et de réfléchir aux conséquences sociologiques de ses usages. Cet effort interprétatif, qui conjugue sur le plan analytique plusieurs points de vue sociolinguistique, historique anthropologique et philosophique, a pour principal résultat de commencer à mettre en évidence une autre facette de la mexicanité inscrite dans les rapports de force et les rapports de sens, qui structurent une large partie de la société mexicaine d’aujourd’hui, et qui tient à ce que l’on pourrait identifier comme un phénomène de discrimination esthétique, véritable antichambre d’un racisme autant social que culturel. Finalement, si chaque Mexicain tient un peu du naco et s’il considère par ailleurs que son voisin de palier ou son Beau frère incarne davantage cette figure culturelle, il convient de reconnaître que cette affaire de goût est un donné universel.Drawing from the later Wittgenstein, author of the Philosophical Investigations, according to which words have palpable effects, the goal of this article is to present and interrogate the Mexican cultural category of the naco, with the related terms naquez and naquisa. The meaning of this cluster of terms is more or less equivalent to the French vernacular plouc. It is defined by a sort of “bad taste,” but also carries a racializing charge. The article also reflects on the sociological uses of these terms. The main result of this interpretive work, which gathers sociolinguistic, historic, anthropological, and philosophical concerns analytically, is to begin to throw into relief another facet of Mexican identity. The « naco » concept forms part of the relations of power and

  1. Contribution a l'etude et a la conception d'une machine synchrone a flux transverse destinee au degivrage d'aeronefs en cours de vol

    Science.gov (United States)

    Boussetoua, Mohammed

    During winter, the climate in the northern region is known for its icing and freezing conditions. However, emergency services often use helicopters to reach isolated locations. The difficult situations, generally experiences in the North particularly in Quebec, may prevent rescuers to intervene. The main reason preventing such operations is the lack of a de-icing system in the small helicopter blades. The overall objective of the project is research, development, design and manufacture of a system composed of an on-board rotating low speed generator and heating elements. It consumes a part of the power supplied by the turbine through the axis of the main rotor of the small aircraft and converts it to electrical power to be used by the heating elements. This innovation will allow to fly safely everywhere throughout the year protect the lives of the users even in the worst weather conditions. Firstly, the research focuses on the identification of problems related to the use of protection systems against the hoarfrost on main rotor blades of different aircrafts during flight. In this phase, we specifically focused on the difficulties encountered by the aircraft companies using the existing and operational systems for protection against hoarfrost. Main rotor blades are difficult to protect on helicopters. Several systems were considered by the helicopter manufacturers, such as electrothermal systems, pneumatic systems or using anti-icing fluids. In the current state of technological knowledge, all helicopters that have been certified to fly in icing conditions use electrothermal systems for protection against hoarfrost on their main rotor Small helicopters addressed by this work, are forbidden to fly in icing conditions due to lack of energy source to operate these systems. The electrothermal system has been considered for this thesis work to protect the main rotor blades of small aircraft in-flight. The second part of this thesis is based on the source of power

  2. 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)

  3. Impact de la dynamique cotonnière sur le développement rural. Etude de cas de la région de Korhogo, au Nord et au Centre de la Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Lebailly P.

    2006-01-01

    Full Text Available Impact of cotton dynamics on rural development: a case study of Korhogo area, in the northern and central IvoryCoast. Cotton cropping is the main cash crop in several African countries. This is the case of Mali where it provides 45 to65% of exportation incomes. Other countries can be added as Burkina Faso where cotton represents the fi rst export productgenerating 50 to 60% of foreign currency returns and Benin, in a lesser extent (only 30% of exports. Unlike these threecountries, Ivory Coast has a weaker cotton sector which counts only for less than 10% of the export incomes. Cotton is the thirdmost important industrial crop of the nation after cocoa and coffee. Nevertheless, cotton is the main cash crop and economicresource in the savannah area, although it has little relative importance at the national level. By 1995, fi bre production averages150 000 tons per annum, of which 90% are exported. The present study focuses on the particular case of the Ivorian cottonsector that benefi ted from agricultural research and extension training programs, and made it evolving within agriculturalproduction systems. As a matter of fact, cotton cropping changed from a mixed cropping with food crops into a monoculturesystem which plays as the economy driver of these regions. The fi rst part is dedicated to general comments. The second partreports on the technical impact of cotton cropping. The third part deals with the socio-economic impact, analysing the farmeragricultural incomes and their uses.

  4. Etude de pratiques d'enseignement relatives a la modelisation en sciences et technologies avec des enseignants du secondaire

    Science.gov (United States)

    Aurousseau, Emmanuelle

    Les modeles sont des outils amplement utilises en sciences et technologies (S&T) afin de representer et d’expliquer un phenomene difficilement accessible, voire abstrait. La demarche de modelisation est presentee de maniere explicite dans le programme de formation de l’ecole quebecoise (PFEQ), notamment au 2eme cycle du secondaire (Quebec. Ministere de l'Education du Loisir et du Sport, 2007a). Elle fait ainsi partie des sept demarches auxquelles eleves et enseignants sont censes recourir. Cependant, de nombreuses recherches mettent en avant la difficulte des enseignants a structurer leurs pratiques d’enseignement autour des modeles et de la demarche de modelisation qui sont pourtant reconnus comme indispensables. En effet, les modeles favorisent la conciliation des champs concrets et abstraits entre lesquels le scientifique, meme en herbe, effectue des allers-retours afin de concilier le champ experimental de reference qu’il manipule et observe au champ theorique relie qu’il construit. L’objectif de cette recherche est donc de comprendre comment les modeles et la demarche de modelisation contribuent a faciliter l’articulation du concret et de l’abstrait dans l’enseignement des sciences et des technologies (S&T) au 2eme cycle du secondaire. Pour repondre a cette question, nous avons travaille avec les enseignants dans une perspective collaborative lors de groupes focalises et d’observation en classe. Ces dispositifs ont permis d’examiner les pratiques d’enseignement que quatre enseignants mettent en oeuvre en utilisant des modeles et des demarches de modelisation. L’analyse des pratiques d’enseignement et des ajustements que les enseignants envisagent dans leur pratique nous permet de degager des connaissances a la fois pour la recherche et pour la pratique des enseignants, au regard de l’utilisation des modeles et de la demarche de modelisation en S&T au secondaire.

  5. Electronic Absorption and MCD Spectra for Pd(AuPPh(3))(8)(2+), Pt(AuPPh(3))(8)(2+), and Related Platinum-Centered Gold Cluster Complexes.

    Science.gov (United States)

    Adrowski, Michael J.; Mason, W. Roy

    1997-03-26

    Electronic absorption and 7.0 T magnetic circular dichroism (MCD) spectra in the UV-vis region, 1.6 to approximately 4.0 &mgr;m(-)(1) (1 &mgr;m(-)(1) = 10(4) cm(-)(1)) are reported for [Pd(AuPPh(3))(8)](NO(3))(2) and [Pt(AuPPh(3))(8)](NO(3))(2) in acetonitrile solutions at room temperature. The MCD spectra are better resolved than the absorption spectra and consist of both A and B terms. The spectra are interpreted in terms of D(4)(d)() skeletal geometry and MO's that are approximated by 5s and 6s orbitals for Pd and Pt/Au atoms, respectively. The lowest energy excited configurations and states are attributed to intraframework (IF) Au(8)(2+) transitions. Evidence is also presented for Pt 5d --> Au 6s transitions in the MCD spectra for Pt(AuPPh(3))(8)(2+). Acetonitrile solution absorption and MCD spectra for the related Pt-centered cluster complexes [Pt(CO)(AuPPh(3))(8)](NO(3))(2), [Pt(AuP(p-tolyl)(3))(8)](NO(3))(2), [Pt(CuCl)(AuPPh(3))(8)](NO(3))(2), [Pt(AgNO(3))(AuPPh(3))(8)](NO(3))(2), [Pt(Hg)(2)(AuPPh(3))(8)](NO(3))(2), [Pt(HgCl)(2)(AuPPh(3))(8)](BF(4))(2), and [Pt(HgNO(3))(2)(AuPPh(3))(8)](BF(4))(2) are also reported and interpreted within the context of the model developed for the M(AuPPh(3))(8)(2+) complexes.

  6. Age-hardening and related phase transformation in an experimental Ag-Cu-Pd-Au alloy

    International Nuclear Information System (INIS)

    Seol, Hyo-Joung; Lee, Doung-Hun; Lee, Hee-Kyung; Takada, Yukyo; Okuno, Osamu; Kwon, Yong Hoon; Kim, Hyung-Il

    2006-01-01

    The age-hardening behaviour, phase transformation and related microstructural changes of an experimental Ag-Cu-Pd-Au alloy were examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The specimen alloy showed apparent age-hardenability at the aging temperatures of 350 deg. C and 400 deg. C. By aging the solution-treated specimen at 400 deg. C, two phases of the Ag-rich α 1 phase and the Pd-containing Cu-rich α 2 phase were transformed into four phases of the Ag-rich α 1 ' phase, the Cu-rich α 2 ' phase, the CsCl-type CuPd phase and the AuCu(I) ordered phase. Microstructure of the solution-treated specimen consisted of the Ag-rich α 1 matrix, Cu-rich α 2 particle-like structures of various sizes and the lamellar structure of the α 1 and α 2 phases. When the peak hardness was obtained, the very fine lamellar structure consisting of the Ag-rich α 1 ' and Cu-rich α 2 ' phases was newly formed in the matrix. By further aging, the very fine lamellar structure grew and coarsened apparently, and the matrix was covered with the coarsened lamellar structure. The hardness increase was considered to be caused mainly by the diffusion and precipitation of Cu from the Ag-rich α 1 matrix, and the hardness decrease in the latter stage of age-hardening process was caused by the coarsening of the very fine lamellar structure. The CsCl-type CuPd phase and the AuCu(I) ordered phase did not contribute to the hardness increase

  7. Age-hardening and related phase transformation in an experimental Ag-Cu-Pd-Au alloy

    Energy Technology Data Exchange (ETDEWEB)

    Seol, Hyo-Joung [Department of Dental Materials, College of Dentistry, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Lee, Doung-Hun [Department of Dental Materials, College of Dentistry, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Lee, Hee-Kyung [Department of Dental Technology, Daegu Health College, San 7 Taejeon-dong, Buk-gu, Daegu 702-722 (Korea, Republic of); Takada, Yukyo [Division of Dental Biomaterials, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Okuno, Osamu [Division of Dental Biomaterials, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Kwon, Yong Hoon [Department of Dental Materials, College of Dentistry, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Kim, Hyung-Il [Department of Dental Materials, College of Dentistry, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of)]. E-mail: hilkim@pusan.ac.kr

    2006-01-05

    The age-hardening behaviour, phase transformation and related microstructural changes of an experimental Ag-Cu-Pd-Au alloy were examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The specimen alloy showed apparent age-hardenability at the aging temperatures of 350 deg. C and 400 deg. C. By aging the solution-treated specimen at 400 deg. C, two phases of the Ag-rich {alpha}{sub 1} phase and the Pd-containing Cu-rich {alpha}{sub 2} phase were transformed into four phases of the Ag-rich {alpha}{sub 1}{sup '} phase, the Cu-rich {alpha}{sub 2}{sup '} phase, the CsCl-type CuPd phase and the AuCu(I) ordered phase. Microstructure of the solution-treated specimen consisted of the Ag-rich {alpha}{sub 1} matrix, Cu-rich {alpha}{sub 2} particle-like structures of various sizes and the lamellar structure of the {alpha}{sub 1} and {alpha}{sub 2} phases. When the peak hardness was obtained, the very fine lamellar structure consisting of the Ag-rich {alpha}{sub 1}{sup '} and Cu-rich {alpha}{sub 2}{sup '} phases was newly formed in the matrix. By further aging, the very fine lamellar structure grew and coarsened apparently, and the matrix was covered with the coarsened lamellar structure. The hardness increase was considered to be caused mainly by the diffusion and precipitation of Cu from the Ag-rich {alpha}{sub 1} matrix, and the hardness decrease in the latter stage of age-hardening process was caused by the coarsening of the very fine lamellar structure. The CsCl-type CuPd phase and the AuCu(I) ordered phase did not contribute to the hardness increase.

  8. Contribution to the study and to the development of continuous infrared absorption analyzers; Contribution a l'etude et a la mise au point des analyseurs en continu par absorption infrarouge

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-12-01

    The continuous infra-red absorption determination of corrosive gases implies the construction of an original single-beam spectrometer. The use of a vibration-rotation line means that the apparatus function has to undergo an alternating displacement: for one position this function is centered on the line, for other position it is placed close by, but away from any absorption. A non-linear relationship is derived between the concentration of the impurity under consideration, the optical density measured at the centre of the line and the total pressure of the gas mixture. The problem is then solved using an associated specific analog computer. The system is applicable to the determination of low concentrations. The principle proposed in then adapted to an analysis using a non-resolved vibration-rotation band. (authors) [French] Le dosage en continu par absorption infrarouge des gaz corrosifs, implique la construction d'un spectrometre original en simple faisceau. L'utilisation d'une raie de vibration - rotation, conduit a effectuer un deplacement alternatif de la fonction d'appareil: pour une position, celle-ci est centree sur la raie, pour l'autre position elle est placee a proximite mais en dehors de toute absorption. On etablit une relation non lineaire entre la concentration de l'impurete consideree, la densite optique mesuree au centre de la raie et la pression totale du melange gazeux. Le probleme est alors resolu par un calculateur analogique specifique associe. Le systeme s'applique au dosage des faibles concentrations. Le principe propose est ensuite adapte a l'analyse a partir d'une bande de vibration - rotation non resolue. (auteurs)

  9. Simulation of phase I FOPI detector and the study of the double differential cross sections of the fragment production in Au + Au collisions at 600 and 800 A.MeV; Simulation du detecteur FOPI phase I et etude des sections efficaces doublement differentielles de production de fragments dans les collisions Au + Au A 600 et 800 A.MeV

    Energy Technology Data Exchange (ETDEWEB)

    Berger, L. [Ecole Doctorale des Sciences Fondamentales, Clermont-Ferrand-2 Univ., 63 - Aubiere (France). U.F.R. de Recherche Scientifique et Technique

    1995-10-13

    This thesis has two parts. The first one is devoted to the study of influence of multiple collisions on various variables by means of the interface GEANT-FOPI. The second part deals with the study of mass double differential cross sections relative to rapidity and transverse energy obtained by phase I FOPI detector. It was found that the estimate of the rate of double collisions is strongly dependent on the utilised model and that the influence of multiple collisions on the double differential cross sections was negligible for rapidities near that of mass center. The second part of this work is devoted to the study of double differential cross sections of fragment production. The fitting of experimental distributions with the Boltzmann law seems to be convenient for the Z=1 fragments emitted in central collisions. The hypothesis of a unique pure thermal source is to be excluded for the Z > 1 fragments. In the case of central collisions, the consideration of the collective effects occurring, in the case of a thermal source explosion followed by an isotropic radial collective expansion, has resulted in a unique temperature value for Z=1 and Z=2, as well as, in a value of collective radial speed, of the order of magnitude of 0.3 c, common for all the fragments. The experimental findings achieved with the phase I FOPI detector allowed to conclude firmly that this scenario, implying an isotropic radial expansion, is strongly made evident in case of central reactions. In addition, the comparison of experimental data with the results obtained with the Isospin Quantum Molecular Dynamics model has shown that, in spite of an overall overestimation of distributions, a good agreement between theoretical estimates and experimental data was obtained for the collective temperature and speed values 76 refs.

  10. Aerodynamic and thermal studies of cans of gas cooled fuel elements; Etudes aerodynamiques et thermiques de gaines d'elements combustibles refroidis par gaz

    Energy Technology Data Exchange (ETDEWEB)

    Gelin, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Milliat, J P [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    Research on clusters was undertaken at the CEA in 1959, while studies on herring-bone cans were developed at the EDF Laboratory at Chatou and the CEA laboratory at Saclay at the end of 1959. In 1962, a general study on corrugations was begun at the Saclay Laboratory with a view to improving the clusters, and continued later in both laboratories relative to the internal cooling of annular fuel elements. As these studies progressed, trial facilities were extended while experimental methods have improved constantly. At the present time, both laboratories, working in complete collaboration, have powerful means at their disposal. Work on the clusters has been concerned chiefly with pressure losses due to the assembly parts, and with the temperature variations around the elements of the cluster. In this way, we have been able to determine satisfactorily the hot points of the can, the deformations of the rods and the conditions of stability of these deformations. In the case of the herring-bone cans, studies have been directed to the evolution of performances as a function of the geometric parameters on the one hand, and to the special aerodynamic and thermal features caused by the fins and by interruptions of cartridge on the other hand. These studies have led to a very thorough knowledge of the cartridges chosen for the reactors EDF 2 and EDF 3, and now open up very hopeful prospects for future reactors, particularly those fitted with annular elements; among the alternatives suitable for the inner surface of the annular element can, corrugations and longitudinal fins have been fairly extensively tested over a wide range of Reynolds number. (authors) [French] Les etudes de grappes ont ete entreprises au C.E.A. en 1959, tandis que les etudes de gaines a chevrons se sont developpees au Laboratoire de Chatou de l'EDF et au Laboratoire de Saclay du C.E.A. a la fin de l'annee 1959. En 1962, une etude generale sur les corrugations a ete commencee au Laboratoire de Saclay pour

  11. Thermoelectric properties of currently available Au/Pt thermocouples related to the valid reference function

    Directory of Open Access Journals (Sweden)

    Edler F.

    2015-01-01

    Full Text Available Au/Pt thermocouples are considered to be an alternative to High Temperature Standard Platinum Resistance Thermometers (HTSPRTs for realizing temperatures according to the International Temperature Scale of 1990 (ITS-90 in the temperature range between aluminium (660.323 °C and silver (961.78 °C. The original aim of this work was to develop and to validate a new reference function for Au/Pt thermocouples which reflects the properties of presently commercially available Au and Pt wires. The thermoelectric properties of 16 Au/Pt thermocouples constructed at different National Metrological Institutes by using wires from different suppliers and 4 commercially available Au/Pt thermocouples were investigated. Most of them exhibit significant deviations from the current reference function of Au/Pt thermocouples caused by the poor performance of the Au-wires available. Thermoelectric homogeneity was investigated by measuring immersion profiles during freezes at the freezing point of silver and in liquid baths. The thermoelectric inhomogeneities were found to be one order of magnitude larger than those of Au/Pt thermocouples of the Standard Reference Material® (SRM® 1749. The improvement of the annealing procedure of the gold wires is a key process to achieve thermoelectric homogeneities in the order of only about (2–3 mK, sufficient to replace the impracticable HTSPRTs as interpolation instruments of the ITS-90. Comparison measurements of some of the Au/Pt thermocouples against a HTSPRT and an absolutely calibrated radiation thermometer were performed and exhibit agreements within the expanded measurement uncertainties. It has been found that the current reference function of Au/Pt thermocouples reflects adequately the thermoelectric properties of currently available Au/Pt thermocouples.

  12. Relative humidity sensor based on surface plasmon resonance of D-shaped fiber with polyvinyl alcohol embedding Au grating

    Science.gov (United States)

    Yan, Haitao; Han, Daofu; Li, Ming; Lin, Bo

    2017-01-01

    This paper presents the design, fabrication, and characterization of a D-shaped fiber coated with polyvinyl alcohol (PVA) embedding an Au grating-based relative humidity (RH) sensor. The Au grating is fabricated on a D-shaped fiber to match the wave-vector and excite the surface plasmon, and the PVA is embedded in the Au grating as a sensitive cladding film. The refractive index of PVA changes with the ambient humidity. Measurements in a controlled environment show that the RH sensor can achieve a sensitivity of 5.4 nm per relative humidity unit in the RH range from 0% to 70% RH. Moreover, the surface plasmon resonance can be realized and used for RH sensing at the C band of optical fiber communication instead of the visible light band due to the metallic grating microstructure on the D-shaped fiber.

  13. Alecto 2 - interaction studies; Alecto 2 - etudes d'interaction

    Energy Technology Data Exchange (ETDEWEB)

    Brunet, J P; Clouet d' Orval, Ch; Mougniot, J C; Penet, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Weak interactions were experimentally studies with the tank of the critical assembly Alecto II and one, two or three bottles containing solutions of various concentrations. In particular, was studied the validity of certain classical assumptions, shielding effects, screening and semi-reflexion effects, importance of thermal coupling. The method of the 'k{sub eff}, solid angle' is shown to apply to such a system. The determination by divergence and pulsed neutron technique of the reactivity related to a millimeter of solution level affords the obtention of critical heights in terms of reactivity. (authors) [French] Une etude experimentale d'interactions faibles a ete faite entre la cuve de l'experience critique ALECTO II et une, deux ou trois bouteilles contenant des concentrations variees. On etudie, en particulier, la validite de certaines hypotheses classiques, effets d'ombre, d'ecrans, de semi-reflexion, importance du couplage thermique. On montre d'autre part que la methode du 'K{sub eff}, angle solide' peut s'appliquer a un tel systeme. La determination par divergence et neutrons pulses de la reactivite liee au millimetre de solution permet de traduire les hauteurs critiques obtenues, en terme de reactivite. (auteurs)

  14. Nouvelles: KEK: B pour BELLE; NA48 mesure la violation directe de CP; LEL: le laser à électrons libres dépasse le kilowatt; Le LEP à 100 pour 100; Tour d'honneur au RHIC; Mesures de précision; Etude sur les modes de gestion du village planétaire; Conférence PANIC99 à Uppsala; Rencontre électron-noyau à HERA; LPP, Doubna célèbre une décennie; Les physiciens auscultent le photon; Aimants chauds venus du froid

    CERN Multimedia

    1999-01-01

    Nouvelles: KEK: B pour BELLE; NA48 mesure la violation directe de CP; LEL: le laser à électrons libres dépasse le kilowatt; Le LEP à 100 pour 100; Tour d'honneur au RHIC; Mesures de précision; Etude sur les modes de gestion du village planétaire; Conférence PANIC99 à Uppsala; Rencontre électron-noyau à HERA; LPP, Doubna célèbre une décennie; Les physiciens auscultent le photon; Aimants chauds venus du froid

  15. Contribution to the study of radio toxicity of aromatic and medicinal plants using solid state nuclear track detectors; Contribution a l etude de la radio toxicite des plantes aromatiques et medicinales au moyen des detecteurs solides de traces nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Mortassim, A; Misdaq, M A; Naaman, A

    2009-07-01

    The concentrations of uranium (238 U), thorium (232 Th), radon (222 Rn) and thoron (220 Rn) were measured in twenty aromatic and medicinal plants in {sup f}ind a new method based on using solid state nuclear track detectors type Cr-39 and Rs-115. He emerges from this study that the verbena and salvia have higher levels of uranium (radon) higher than that of other plants while the leaves of olive and saturja have concentrations of thorium (thoron) higher than other plants therefore radio toxicity of these plants is higher than that of others and may pose a radiological hazard if the masses are incorporated by consumers high. [French] Les concentrations en uranium (238U), thorium (232Th), radon (222Rn), et thoron (220Rn) ont ete mesurees dans vingt plantes aromatiques et medicinales en utilsant une nouvelle methode basee sur l utilisation des detecteurs solides de traces nucleaires de types CR-39 et LR-115. Il en sort de cette etude que la verveine et la salvia presentent des teneurs en uranium (radon) superieurs a celle des autres plantes alors que les feuilles d olivier et la saturja presentent des concentrations en thorium (thoron) plus elevee que celles des autres plantes par consequent la radio toxicite de ces plantes est superieure a celles des autres et peuvent presenter un risque radiologique si les masses incorporees par les consommateurs sont elevees.

  16. Treatment of effluent at the Saclay Centre d'Etudes Nucleaires (1960); Le traitement des effluents du Centre d'Etudes Nucleaires de Saclay (1960)

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    The Centre d'Etudes Nucleaires at Saclay possesses several installations from which liquid radioactive effluent is rejected, and it has thus been found necessary to construct a station for the purification of radioactive liquids and to settle various chemical, analytical and technological problems. This report describes, in the following order: - the disposal possibilities at the Centre d'Etudes Nucleaires, Saclay, - the effluents produced at the centre, - the set-up for collecting effluent, - treatment of the effluent, - results of these treatments. (author) [French] La presence, au Centre d'Etudes Nucleaires de Saclay, de plusieurs installations susceptibles de rejeter des effluents liquides radioactifs a necessite la construction d'une station d'epuration d'eaux radioactives et la mise au point de differents problemes chimiques, analytiques et technologiques. Dans ce rapport, nous exposerons successivement: - les possibilites de rejet du Centre d'Etudes Nucleaires de Saclay, - les effluents du centre, - le dispositif de collecte des effluents, - le traitement de ces effluents, - les resultats de ces traitements. (auteur)

  17. Observation of Au + AuAu + Au + ρ0 and Au + AuAu* + Au* + ρ0 with STAR

    International Nuclear Information System (INIS)

    Spencer, K.

    2002-01-01

    First observation of the reactions Au + AuAu + Au + ρ 0 and Au + AuAu* + Au* + ρ 0 with the STAR detector are reported. The ρ are produced at small perpendicular momentum, as expected if they couple coherently to both nuclei. Models of vector meson production and the correlation with nuclear breakup are discussed, as well as a fundamental test of quantum mechanics that is possible with the system. (author)

  18. Contribution to the study of the sintering of ex-carbonyl iron in the {alpha} and {gamma} phases using the micro-fractographic technique; Contribution a l'etude du frittage du fer ex-carbonyle en phases {alpha} et {gamma} par examen des surfaces de rupture au microscope electronique

    Energy Technology Data Exchange (ETDEWEB)

    Oxley Gaborit de Montjou, M.Th. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-07-01

    granules a l'interieur des grains {alpha} finaux dans le fer directement fritte dans le bas du domaine {gamma}, meme apres plusieurs heures de frittage; -) une compression intermediaire permet une reprise du frittage suffisante pour depasser le stade de la structure a granules; -) un net ralentissement du frittage si le point A{sub 3} est franchi une ou plusieurs fois au cours du frittage en {alpha}; -) une cinetique du frittage elevee si le traitement en {gamma} est effectue a 1300 C ou au-dessus de 1300 C. Les resultats de cette etude sont en accord avec les observations micrographiques ainsi qu'avec les mesures dilatometriques et les valeurs connues des coefficients d'autodiffusion.

  19. Contribution to the studies on the mineral content of plant material through radioactivation analysis; Contribution a l'etude de la composition minerale des matieres vegetales au moyen de l'analyse par radioactivation

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-03-15

    Radioactivation analysis is by its great sensibility or its rapidity quite helpful in plant biology and agronomy. Specific composition of plants and results to obtain in biological experimentation have needed a practical research on analytical methods for plant materials, using for radioactivation swimming-pool reactor neutrons and 14 MeV neutrons from a generator. Dosage process for 25 elements is exposed, taking account of the interest of the analysis for each element, the average amount occurring in plants and the result obtained. Many applications are developed, concerning nutrition physiology, genetics, parasitology, toxicology, control of manufactured agricultural and pharmaceutical products industrial and pesticides residues, ecology, radioecology and biochemistry. (author) [French] L'analyse par radioactivation, par sa grande sensibilite ou sa rapidite, est susceptible de rendre de nombreux services en biologie vegetale et en agronomie. La composition particuliere des plantes et les buts recherches dans l'experimentation ont exige une etude concrete des methodes d'analyse propres a la matiere vegetale en utilisant, pour la radioactivation, soit un reacteur de type piscine a eau legere, soit un accelerateur generateur de neutrons de 14 MeV. Le mode de dosage de 25 elements est expose en tenant compte de l'interet de l'analyse de chaque element, des teneurs moyennes rencontrees dans les plantes, et du resultat atteint. De nombreuses applications sont developpees qui touchent a la physiologie de la nutrition, la genetique, la parasitologie, la toxicologie, le controle des fabrications, les pollutions industrielles, l'ecologie, la radioecologie et la biochimie. (auteur)

  20. Contribution to the studies on the mineral content of plant material through radioactivation analysis; Contribution a l'etude de la composition minerale des matieres vegetales au moyen de l'analyse par radioactivation

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-03-15

    Radioactivation analysis is by its great sensibility or its rapidity quite helpful in plant biology and agronomy. Specific composition of plants and results to obtain in biological experimentation have needed a practical research on analytical methods for plant materials, using for radioactivation swimming-pool reactor neutrons and 14 MeV neutrons from a generator. Dosage process for 25 elements is exposed, taking account of the interest of the analysis for each element, the average amount occurring in plants and the result obtained. Many applications are developed, concerning nutrition physiology, genetics, parasitology, toxicology, control of manufactured agricultural and pharmaceutical products industrial and pesticides residues, ecology, radioecology and biochemistry. (author) [French] L'analyse par radioactivation, par sa grande sensibilite ou sa rapidite, est susceptible de rendre de nombreux services en biologie vegetale et en agronomie. La composition particuliere des plantes et les buts recherches dans l'experimentation ont exige une etude concrete des methodes d'analyse propres a la matiere vegetale en utilisant, pour la radioactivation, soit un reacteur de type piscine a eau legere, soit un accelerateur generateur de neutrons de 14 MeV. Le mode de dosage de 25 elements est expose en tenant compte de l'interet de l'analyse de chaque element, des teneurs moyennes rencontrees dans les plantes, et du resultat atteint. De nombreuses applications sont developpees qui touchent a la physiologie de la nutrition, la genetique, la parasitologie, la toxicologie, le controle des fabrications, les pollutions industrielles, l'ecologie, la radioecologie et la biochimie. (auteur)

  1. Etude des caractéristiques structurales et des propriétés de verres riches en terres rares destinés au confinement des produits de fission et éléments à vie longue

    OpenAIRE

    Bardez , Isabelle

    2004-01-01

    Une nouvelle matrice vitreuse riche en terres rares, capable d'incorporer les déchets issus du retraitement de combustibles nucléaires UOX à hauts taux de combustion (60 GWj/t, à comparer à 33 GWj/t pour le combustible de référence actuel) a été mise au point et étudiée au niveau structural. Sa composition molaire simplifiée est la suivante : 61 ,79 SiO2 - 8,94 B2O3 - 3,05 Al2O3 - 14,41 Na2O - 6,32 CaO - 1,89 ZrO2 - 3,60 TR2O3 (avec TR = La, Ce, Pr et Nd) En particulier, l'environnement local...

  2. Nuclear study of Melusine; Etude nucleaire de Melusine

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    In this report are reviewed - with respect to starting of experiments - the main nuclear characteristics of a 20 per cent enriched uranium lattice, with light water as moderator and reflector. The reactor is to operate at 1 MW. 1) Study of various critical masses. 2) Control. Effectiveness of cadmium. Control rods and of a stainless steel regulating rod. 3) Study of the effect on reactivity of disturbances in the core center. 4) Study of xenon and samarium poisoning. 5) Temperature factor. 6) Heat exchanges in a fuel element. (author) [French] On etudie, dans ce rapport, les principales proprietes nucleaires d'un reseau a uranium enrichi (20 pour cent), dont le moderateur et le reflecteur sont l'eau legere en vue des experiences de demarrage. Ce reacteur devra fonctionner a 1 MW. 1) Etude de diverses masses critiques. 2) Controle. Efficacite des barres de controle en cadmium et d'une barre de reglage en acier inoxydable. 3) Etude de l'effet sur la reactivite de perturbation au centre du coeur. 4) Etude de l'empoisonnement xenon et samarium. 5) Coefficient de temperature. 6) Echanges thermiques dans un element. (auteur)

  3. Etude de la production de photons isolés dans les états finals hadroniques des collisions e+e- au LEP dans l'expérience ALEPH

    CERN Document Server

    Si Mohand, D

    Les photons isolés, observés dans les désintégrations hadroniques du bozon Z0 créé dans les annihilations électron-positron au LEP, proviennent essentiellement du rayonnement électromagnétique des quarks. Ces photons, qui ne sont pas affectés par la fragmentation, sont particulièrement sensibles à l'émission de gluons; leur étude, à l'aide d'algorithmes de simulation tels que JETSET, ARIADNE et HERWIG, constitue un moyen simple et précis de tester les différentes approches de QCD, en particulier dans la description de la compétition photon-gluon. Notre analyse a révélé que JETSET prédit (20±6)% moins de photons directs que le nombre mesuré expérimentalement. ARIADNE, en revanche, semble surestimer légèrement le taux de production de photons directs de (6±4)% alors que HERWIG reproduit fidèlement l'ensemble de nos mesures. Après correction des pertes d'acceptance et des effets d'hadronisation, le rapport d'embranchement du Z0 en hadrons plus photon, normalisé au rapport d'embranc...

  4. L' approche des options stratégiques des acteurs dans i' etude des relations tu travail

    OpenAIRE

    López Pino, Carmen Marina

    2011-01-01

    Faire une analyse de la proposition analytique développée par le MIT (Masachussetts Institute of Tecnology) inspirée du concept des options stratégiques pour I' objet de cet article. En premier lieu, les sujets traités seront la problematique des relations du travail et les découvertes fondamentales des différentes recherches de I' equipe du MIT. Après, I' étude fait une courte présentatión sur I' approche des systémes de Dunlop dont I' èquipe cherche améliorer. Ensuite, sont présentés...

  5. Contribution to the study of hydrogenated and oxygenated impurities in liquid sodium; Contribution a l'etude des impuretees hydrogenees et oxygenees dans le sodium liquide

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-15

    This study is made up essentially of two parts. The first is devoted to the development of dosage methods for selectively determining the oxygenated and hydrogenated impurities present in sodium, that is the oxide, the hydride and the hydroxide. The second makes use of these methods for a study of the Na-H{sub 2}-O{sub 2} system, as well as of the related problem of the attack of pyrex glass by molten sodium. The conventional method for dosing oxygen by amalgamation was first adapted to the simultaneous measurement of the hydride. We then developed a method for dosing the total hydrogen by measuring successively the concentrations of gas present in the hydride and hydroxide form. This method is based on the thermal decomposition of the hydride and the reaction between sodium and the hydroxide. Our contribution to the study of the Na-H{sub 2}-O{sub 2} System consists first of all in the study of the reaction between hydrogen and sodium in the temperature range from 150 to 250 deg C and at a pressure of about 150 mm of mercury. The study of the thermal decomposition of the hydride in sodium was then studied. It was possible to make some qualitative observations concerning the reaction between sodium and sodium hydroxide. Finally some complementary tests made it possible to define the nature of the phenomena occurring during the attack of pyrex glass by sodium. (author) [French] Cette etude comporte essentiellement deux parties. La premiere est consacree a la mise au point de methodes de dosages permettant de determiner selectivement les impuretes oxygenees et hydrogenees presentes dans le sodium, a savoir l'oxyde, l'hydrure et l'hydroxyde. La seconde met a profit ces methodes en vue de l'etude du systeme Na-H{sub 2}-O{sub 2}. ainsi que du phenomene connexe d'attaque du verre pyrex par le sodium fondu. La methode classique de dosage de l'oxygene par amalgamation a d'abord ete adaptee au dosage simultane de l'hydrure. Nous avons ensuite mis au point le dosage de l

  6. Study of the thermal drop at the uranium-can interface for fuel elements in gas-graphite reactors; Etude de la chute thermique au contact uranium-gaine pour des elements combustibles de reacteur de la filiere graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Faussat, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Levenes, G; Michel, M [Societe Industrielle de Combustible Nucleaire (France)

    1964-07-01

    The report reviews the tests now under way at the CEA, for determining the thermal contact resistance at the uranium-can interface for fuel elements used in gas-graphite type reactors. These are laboratory tests carried out with equipment based on the principle of a heat flow across a stack of test pieces having planar contact surfaces. The following points emerge from this work: - for a metallic uranium element canned in magnesium, of the type G-2 or EDF-2, a value of 0.2 deg C/W/cm{sup 2} seems reasonable for can temperatures of 400 deg C and above. - this value is independent of the micro-geometric state of the uranium surface in a range of roughness which easily includes those observed on tubes and rods produced industrially. - for the internal cans of elements cooled internally and externally, the value of the contact resistance for temperatures of under 400 deg C as a function of the stresses in the can has not yet been measured exactly. (authors) [French] Le rapport fait le point des essais actuellement en cours au CEA pour determiner la resistance thermique de contact uranium-gaine pour des reacteurs de la filiere graphite-gaz. Ces essais sont effectues en laboratoire sur des appareils bases sur le principe d'une circulation de flux de chaleur a travers un empilement d'eprouvettes dont les faces en contact sont planes. De l'etude, il ressort essentiellement que: - pour un element a uranium metallique et gaine de magnesium type G-2 ou EdF-2, on peut admettre la valeur de 0,2 deg C/W/cm{sup 2} pour des temperatures de gaines de 400 deg C et plus. - cette valeur ne depend pas de l'etat de surface microgeometrique de l'uranium pour un domaine de rugosites couvrant largement celles que l'on observe sur des tubes et barreaux fabriques en serie. - pour les gaines internes d'elements a refroidissement interne et externe la valeur de la resistance de contact reste a preciser pour les temperatures inferieures a 400 deg C, en fonction des contraintes existant dans les

  7. Study of the consequences of the rupture of a pressure tube in the tank of a gas-cooled, heavy-water moderated reactor; Etude des consequences de la rupture d'un tube de force dans la cuve d'un reacteur modere a l'eau lourde et refroidi au gaz

    Energy Technology Data Exchange (ETDEWEB)

    Hareux, F; Roche, R; Vrillon, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Bursting of a pressure tube in the tank of a heavy water moderated-gas cooled reactor is an accident which has been studied experimentally about EL-4. A first test (scale 1) having shown that the burst of a tube does not cause the rupture of adjacent tubes, tests on the tank resistance have been undertaken with a very reduced scale model (1 to 10). It has been found that the tank can endure many bursts of tube without any important deformation. Transient pressure in the tank is an oscillatory weakened wave, the maximum of which (pressure peak) has been the object of a particular experimental study. It appears that the most important parameters which affect the pressure peak are; the pressure of the gas included in the bursting pressure tube, the volume of this gas, the mass of air included in the tank and the nature of the gas. A general method to calculate the pressure peak value in reactor tanks has been elaborated by direct application of experimental data. (authors) [French] L'eclatement d'un tube de force dans la cuve d'un reacteur de puissance modere a l'eau lourde et refroidi par un gaz sous pression est un accident qui a ete etudie experimentalement a propos d'EL-4. Un premier essai a l'echelle 1 ayant montre que l'eclatement d'un tube ne provoque pas celui des tubes voisins, des essais relatifs a la tenue de la cuve ont ete effectues sur maquettes a echelle tres reduite (l/lO). Il a ete trouve que la cuve peut supporter plusieurs eclatements de tubes sans deformations notables. La pression transitoire dans la cuve a une allure oscillatoire amortie dont le maximum (pression de pic) a fait l'objet d'une etude experimentale detaillee. Il apparait que les parametres essentiels influant sur cette pression sont: la pression du gaz contenu dans le tube de force, le volume du gaz qui participe a l'eclatement, la flexibilite de la cuve, la masse d'air empoisonnee dans la cuve, la nature du gaz explosant. Une methode generale d'estimation des pics de pression dans

  8. Neutron Investigation of Magnon Spectrum in Haematite; Etude du Spectre de Magnons dans l'Hematite, au Moyen des Neutrons; Nejtronnoe issledovanie spektra magnona v gematite; Estudio, por Metodos Neutronicos, del Espectro de Magnones en la Hematita

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrijevic, Z.; Rzany, H.; Todorovic, J.; Wanic, A. [Institute for Nuclear Physics Cracow (Poland)

    1965-04-15

    faites a Vinea, dans le reacteur RA, au moyen d'un spectrometre a cristal. Des neutrons monochromatiques ({lambda} = 1.314A) ont ete diffuses par un grand monocristal d'hematite ({alpha}-Fe{sub 2}O{sub 3}). Les auteurs ont etudie la distribution angulaire des neutrons diffuses inelastiquement. Pour plusieurs angles de decalage {Delta}{theta} du cristal, ils ont mesure la largeur {Gamma} du faisceau de neutrons diffuses (appele cone de diffusion). Ils ont attribue ce cone a la surface de diffusion des magnons qui entoure le point du reseau reciproque (1,1,1). Pour plusieurs vitesses de magnons, ils ont mesure {Gamma}, en fonction de l'angle de decalage, et l*ont comparee aux points experimentaux. Ils ont constate que dans la direction [111], la vitesse avait une valeur egale a 25,5{+-}1,0 km/s. Ils ont decouvert une anisotropie structurelle de la relation de dispersion des magnons. Ils ont note que la vitesse etait plus elevee pour les directions de propagation paralleles a l'axe [111], ce qui concorde qualitativement avec les mesures anterieures (faites par Riste et d'autres) qui ont donne v = 38 km/s. Il n'a pas ete possible de mettre en evidence l'existence d'une discontinuite Eg dans la bande acoustique de l'energie des magnons. Selon les evaluations, Eg doit avoir une valeur inferieure a 1 meV. En utilisant le formalisme de Wallace, les auteurs ont calcule les relations de dispersion des magnons dans l'hematite. A cet effet, ils ont admis l'existence de deux integrales d'echange J{sub 1} et J{sub 2} qui ne disparaissent pas. J{sub 1} et J{sub 2} expriment le couplage a superechange d'energie entre les spins d'ions Fe voisins lies par l'intermediaire d'un ion oxygene. Les angles Fe-O-Fe des liaisons considerees sont respectivement de 132 et 126 Degree-Sign . Les resultats theoriques et les donnees experimentales actuelles concordent de facon satisfaisante lorsque SJ{sub 1} = SJ{sub 2} = 5,1 meV. Outre la branche acoustique des magnons, les calculs ont revele l

  9. A treatment station for solid radio-active waste at the Saclay nuclear research centre (1962); Station de traitement des dechets radioactifs solides au centre d'etudes nucleaires de Saclay (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Cerre, P; Mestre, E; Lebrun, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    The waste from an atomic centre is very varied in nature, in form, and in activity, going from weakly contaminated laboratory waste to objects actuated in a pile and strongly radioactive. After one year's working of a pilot plant, a factory has been built, in which solide waste is treated and then conditioned in concrete blocks. The present communication describes the treatment and conditioning techniques in this factory which uses to a maximum remotely controlled operation. (authors) [French] Les dechets d'un Centre Atomique sont de natures, de forme et d'activites extremement variees, allant des dechets de laboratoires faiblement contamines, aux dispositifs actives en pile et fortement radioactifs. Apres l'exploitation pendant un an d'une unite pilote, une usine a ete construite dans laquelle les dechets solides sont traites, puis conditionnes en bloc de beton. La presente communication a pour objet la description des techniques de traitement et de conditionnement dans cette usine ou les operations sont au maximum commandees automatiquement et a distance. (auteurs)

  10. Preparation and study of the properties of lead telluride and cadmium telluride diodes for use in nuclear spectrometry; Preparation et etude des proprietes de diodes au tellurure de plomb et au tellurure de cadmium en vue d'une utilisation en spectrometrie nucleaire

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    This work studies the possibility of using high atomic number compound semiconductors, like lead telluride and cadmium telluride as to realize nuclear radiation detectors, specially in gamma ray spectrometry because of their high absorption coefficient. The problems related to the preparation of binary compounds are exposed. Experiments on PbTe show the influence of the conditions of preparation on the electrical properties of the semiconductor which are greatly dependent on the stoichiometry of the compound. PbTe surface-barrier diodes were realized and have been used to study the surface properties of this semiconductor. These diodes cannot detect nuclear radiations because of the too weak resistivity of our material. Different types of devices made of Cd Te have been studied. One of these diodes has been used as an alpha particle detector. We explain the relative poor performances of that detector by the presence of lattice defects in Cd Te where charge carriers may recombine themselves. By analysing the properties of gold diffused Cd Te diodes we identified this defect, the cadmium vacancy, the presence of which is due to the deviation from stoichiometry during the preparation of the material. (author) [French] Ce travail etudie la possibilite d'utiliser des semiconducteurs composes d'elements a numero atomique eleve, tels que le tellurure de plomb et le tellurure de cadmium pour la realisation de detecteurs de rayonnements nucleaires, grace notamment a la section efficace de capture elevee qu'ils presentent vis-a-vis des rayons gamma. On souligne les problemes relatifs a la preparation des composes binaires. Les experiences realisees sur PbTe mettent en evidence l'influence des conditions de preparation sur les proprietes electriques du semiconducteur qui dependent fortement de la stoechiometrie du compose. Nous avons realise des diodes au PbTe a barriere de surface qui ont permis de preciser les proprietes de surface de ce semiconducteur. La trop faible

  11. Semiconducting La2AuP3, the metallic conductor Ce2AuP3, and other rare-earth gold phosphides Ln2AuP3 with two closely related crystal structures

    International Nuclear Information System (INIS)

    Eschen, M.; Kotzyba, G.; Kuennen, B.; Jeitschko, W.

    2001-01-01

    The compounds Ln 2 AuP 3 were synthesized by reaction of the elemental components in evacuated silica tubes. Their crystal structures were determined from single-crystal diffractometer data. The compounds with Ln = La, Ce, and Pr crystallize with an orthorhombic U 2 NiC 3 type structure (Pnma, Z = 4). The structure refinement for Ce 2 AuP 3 resulted in a = 774.14(6) pm, b = 421.11(4) pm, c = 1612.3(1) pm, R = 0.019 for 1410 structure factors and 38 variable parameters. For Pr 2 AuP 3 a residual of R = 0.024 was obtained. Nd 2 AuP 3 crystallizes with a monoclinic distortion of this structure: P2 1 /c, Z = 4, a = 416.14(4) pm, b = 768.87(6) pm, c = 1647.1(2) pm, β = 104.06(1) , R = 0.022 for 1361 F values and 56 variables. The near-neighbor coordinations of the two structures are nearly the same. In both structures the gold and phosphorus atoms form two-dimensionally infinite nets, where the gold atoms are tetrahedrally coordinated by phosphorus atoms with Au-P distances varying between 245.8 and 284.2 pm. Two thirds of the phosphorus atoms form pairs with single-bond distances varying between 217.7 and 218.9 pm. Thus, using oxidation numbers the structures can be rationalized with the formulas (Ln +3 ) 2 [AuP 3 ] -6 and (Ln +3 ) 2 Au +1 (P 2 ) -4 P -3 . Accordingly, La 2 AuP 3 is a diamagnetic semiconductor. Pr 2 AuP 3 is semi-conducting with an antiferromagnetic ground state, showing metamagnetism with a critical field of B c = 0.5(±0.1) T. In contrast, the cerium compound is a metallic conductor, even though its cell volume indicates that the cerium atoms are essentially trivalent, as is also suggested by the ferro- or ferrimagnetic behavior of the compound. (orig.)

  12. Central Au on Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    Alard, J.P.; Amouroux, V. [Labo de Phys. Corp., IN2P3-CRNS, Univ. Blaise Pascal, Clermont-Fd. (France); Basrak, Z. [Rudjer Boskovic Institute, Zagreb (Croatia)] [and others; FOPI-Collaboration

    1995-02-06

    In nucleus-nucleus collisions the initial relative kinetic energy of target and projectile is available for internal excitation of the interacting system; it is however still not well established to what extent local equilibrium and thermalisation occur. Local equilibrium is of interest to derive, within the formalism of transport equations and of the equation of state, (EOS), general properties of compressed and excited nuclear matter. Such approach describes in relatively simple terms the complex many body interactions occuring within extended baryonic and hadronic (or quark) matter. For a basic microscopic understanding it is highly desirable to investigate the elementary in-medium interactions in relation to the free elementary processes. Excitation function measurements of central collisions between the heaviest available nuclei (like Au on Au), supply the best ground for such studies: the highest degree of thermalisation and compression is expected for such reactions. The consideration presented here of energy thermalisation and of an expanding system clusterizing at freeze-out in a situation close to the liquid gas phase transition can be of interest to astrophysics as well as to the quark gluon plasma deconfinement studied in nucleus-nucleus collisions at the higher energy regime of CERN and Brookhaven. (orig.).

  13. Some equipment for graphite research in swimming pool reactors; Quelques dispositifs d'etude du graphite dans les piles piscines

    Energy Technology Data Exchange (ETDEWEB)

    Seguin, M; Arragon, Ph; Dupont, G; Gentil, J; Tanis, G [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-07-01

    The irradiation devices described are used for research concerning reactors of the natural uranium type, moderated by graphite and cooled by carbon dioxide. The devices are generally designed for use in swimming pool reactors. The following points have been particularly studied: - maximum use of the irradiation volume, - use of the simplest technological solutions, - standardization of certain constituent parts. This standardization calls for precision machining and careful assembling; these requirements are also true when a relatively low irradiation temperature is required and the nuclear heating is pronounced. Finally, the design of these devices is suitable for the irradiation of other fissile or non-fissile materials. (authors) [French] Les dispositifs d'irradiation decrits servent aux etudes relatives a la filiere des reacteurs a uranium naturel, moderes au graphite et refroidis par le gaz carbonique. Ils sont generalement concus pour etre utilises dans des piles piscines. L'accent a ete mis sur: - l'utilisation au maximum du volume d'irradiation, - le recours aux solutions technologiques les plus simples, - la standardisation de certaines parties constitutives. Cette standardisation impose un usinage precis et un montage soigne, lesquels sont egalement necessaires lorsqu'on doit obtenir une temperature d'irradiation relativement basse alors que l'echauffement nucleaire est important. Enfin, la conception de ces dispositifs est valable pour irradier d'autres materiaux non fissiles ou fissiles. (auteurs)

  14. Study of the diffusion of iron, of silver and of carbon in beryllium using radioactive tracers; Etude de la diffusion du fer, de l'argent et du carbone dans le beryllium au moyen des traceurs radioactifs

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-06-01

    .98 exp - [45700 / RT]. L'anisotropie diminue lorsque la temperature croit. L'argent diffuse plus vite suivant l'axe C que dans le plan de base. Ce resultat ne peut etre explique par le modele propose pour la diffusion d'atomes etrangers en solution dans le zinc. Un plus grand nombre d'experiences est necessaire pour tenter de construire un modele. On a egalement tente de determiner les coefficients de diffusion du carbone dans le beryllium par traitement dans une atmosphere d'acetylene marque au carbone 14. Des coefficients de diffusion ent ete obtenus mais ceux-ci ne semblent pas devoir etre pris en consideration car une reaction chimique se produit a la surface des echantillons. (auteur)

  15. Baby fission chambers; Etude de chambres a fission miniatures

    Energy Technology Data Exchange (ETDEWEB)

    Guery, U; Tachon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    The present report is intended, on the one band, as a study of the main types of fission chambers produced to date, and on the other, to deal more generally with this type of detector. Originally, it was with a view to the charting of neutron scatter in 'Proserpine' that the authors undertook the study of these chambers. During the course of the task, it was considered worth tbe trouble of developing its scope to include a more general application: neutron scatter measurement of various energy neutrons within a reduced volume with slight local disturbance. (author) [French] Le present rapport se propose, d'une part, d'exposer les principales realisations de chambres a fission, d'autre part de faire une mise au point a caractere plus general sur ces detecteurs. Au depart, c'est surtout en vue des mesures de densite neutronique dans 'Proserpine' que les auteurs ont etudie ces chambres; au cours de la mise au point, il a paru interessant de developper leur etude pour des applications plus generales: mesures de densites de neutrons de differentes energies dans un element de volume tres reduit et avec faible perturbation locale. (auteur)

  16. Baby fission chambers; Etude de chambres a fission miniatures

    Energy Technology Data Exchange (ETDEWEB)

    Guery, U.; Tachon, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    The present report is intended, on the one band, as a study of the main types of fission chambers produced to date, and on the other, to deal more generally with this type of detector. Originally, it was with a view to the charting of neutron scatter in 'Proserpine' that the authors undertook the study of these chambers. During the course of the task, it was considered worth tbe trouble of developing its scope to include a more general application: neutron scatter measurement of various energy neutrons within a reduced volume with slight local disturbance. (author) [French] Le present rapport se propose, d'une part, d'exposer les principales realisations de chambres a fission, d'autre part de faire une mise au point a caractere plus general sur ces detecteurs. Au depart, c'est surtout en vue des mesures de densite neutronique dans 'Proserpine' que les auteurs ont etudie ces chambres; au cours de la mise au point, il a paru interessant de developper leur etude pour des applications plus generales: mesures de densites de neutrons de differentes energies dans un element de volume tres reduit et avec faible perturbation locale. (auteur)

  17. Study by neutron diffusion of magnetic fluctuations in iron in the curie temperature region; Etude des fluctuations d'aimantation dans le fer au voisinage de la temperature de curie par diffusion des neutrons

    Energy Technology Data Exchange (ETDEWEB)

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

    1958-12-15

    Heinsenberg model and a simple band model; our values in good agreement with those calculated in the Heisenberg model and exclude the band model used. Finally, in chapter IV we recall the chief results obtained. (author) [French] La diffusion critique des neutrons dans le fer est due aux fluctuations d'aimantation qui existent dans les substances ferromagnetiques au voisinage de la temperature de Curie. Les fluctuations peuvent se decrire en termes de correlations; on definit une fonction de correlation: {gamma}{sub R{sub vector}} (t), {gamma}{sub R{sub vector}} (t) , valeur moyenne du produit scalaire d'un spin de reference et d'un spin situe a la distance (R) du premier et considere a l'instant t. Dans le chapitre I nous rappelons les generalites sur les sections efficaces de diffusion des neutrons; nous donnons un bref resume de la theorie de VAN HOVE qui a montre que la section efficace de diffusion magnetique des neutrons est la transformee de FOURIER de la fonction de correlation. Dans le chapitre II nous etudions la dependance spatiale de la fonction de correlation, supposee independante du temps. On peut alors la caracteriser par deux parametres K{sub 1} et r{sub 1} qui permettent de calculer respectivement la portee et l'intensite des correlations. Apres avoir expose le principe de la mesure de ces parametres, nous decrirons l'appareillage experimental. Les valeurs experimentales obtenues sont en bon accord avec celles calculees, l'accord est meilleur si on suppose que ce sont les deuxiemes et non les premiers voisins d'un atome de fer qui sont magnetiquement actifs, ainsi que l'a propose NEEL. Dans le chapitre III nous etudions l'evolution dans le temps de la fonction de correlation; cette evolution est caracterisee par un parametre {lambda} dependant de la temperature, qui intervient dans l'equation de diffusion, a laquelle obeissent les fluctuations d'aimantation {delta}M{sub vector}/{delta}t = {lambda} {nabla

  18. Application de la télédétection et des systèmes d'informations géographiques à l'etude des mouvements de terrain au Liban

    OpenAIRE

    Abdallah , Chadi

    2007-01-01

    Among the various natural hazards, mass movements (MM) are probably the most damaging to the natural and human environment in the Mediterranean countries, including Lebanon which represents a good case study of mountainous landscape. Although affecting vast areas in the country, the phenomenon was not studied at regional scale, and related maps are still lacking. Therefore, this research deals with the use of remote sensing and geographic information system (GIS) techniques in studying MM in ...

  19. The study of quasi-projectiles produced in Ni+Ni and Ni+Au collisions: excitation energy and spin; Etude des quasi-projectiles produits dans les collisions Ni+Ni et Ni+Au: energie d'excitation et spin

    Energy Technology Data Exchange (ETDEWEB)

    Buta, A

    2003-02-01

    During the collision between the projectile and the target nuclei in the intermediate energy regime (E < 100 MeV/nucleon) two excited nuclei are mainly observed in the exit channel, the quasi projectile (QP) and the quasi target. They disintegrate by particle emission. However, this binary picture is perturbed by the emission of particles and light fragments with velocities intermediate between the projectile velocity and the target one, all along the interaction (midrapidity component). This work aim to determine the excitation energy and the intrinsic angular momentum (or spin) of quasi-projectiles produced in the Ni+Ni and Ni+Au collisions at 52 and 90 MeV/nucleon. The excitation energy is deduced from the kinematical characteristics of particles emitted by the quasi-projectile. They have to be separated from midrapidity particles. Three different scenarios have been used for this purpose. The spin of the quasi-projectile has been extracted from the experimental data by mean of proton and alpha particles multiplicities emitted by the QP in the Ni+Au at 52 MeV/nucleon reaction. The results have been compared to the predictions of a theoretical model based on nucleon transfers. Their evolution is qualitatively reproduced as a function of the violence of the collision. (author)

  20. Strontium and caesium transport in unsaturated soil from Chernobyl Pilot Site under steady flow conditions; Transfert de radioelements en zone non saturee. Etude experimentale et modelisation appliquees au Site Pilote de Tchernobyl

    Energy Technology Data Exchange (ETDEWEB)

    Szenknect, St

    2003-10-15

    This work is devoted to the quantification and the identification of the predominant processes involved in strontium and caesium transport in unsaturated soil from Chernobyl Pilot Site under steady flow conditions. The transport and fate of radionuclides in the subsurface is affected by various physical and chemical processes including advective and diffusive transport as well as chemical and biological transformations. Laboratory experiments and the use of a multiple tracer approach allow to isolate the contributions of each elementary process and to control the physico-chemical conditions in the system. To be more representative of the field conditions, we decided to perform column miscible displacement experiments. We perform batch and flow-through reactor experiments to characterize the radionuclides sorption mechanisms. Miscible displacement experiments within homogeneous columns and modeling allow to characterize the hydrodynamic properties of the soil and to describe the radionuclides behaviour under dynamic conditions at different water contents. We show that the water content of porous media affect the transport behaviour of inert and strongly sorbing radionuclides. Our results demonstrate that a parametrized transport model that was calibrated under completely saturated conditions was not able to describe the advective-dispersive transport of reactive solutes under unsaturated steady state conditions. Under our experimental conditions, there is no effect of a decrease of the mean water content on the sorption model parameters, but the transport parameters are modified. We established for the studied soil the relation between hydrodynamic dispersion and water content and the relation between pore water velocity and water content. (author)

  1. Contribution to the study of the {sup 31}P, {sup 1}H spin spin coupling constant N. M. R. in three co-ordinated phosphorus compounds. Influence of the bond orientation and of the nature of the substituent around the phosphorus atom; Contribution a l'etude des constantes de couplage {sup 31}P, {sup 1}H en R.M.N. dans les composes organo-phosphores tricoordines. Influence des facteurs geometriques et de la nature des substituants au niveau du phosphore

    Energy Technology Data Exchange (ETDEWEB)

    Robert, J B [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    In order to investigate the influence of the configuration at the phosphorus atom and the influence of the substituents attached to the phosphorus atom on the J{sub PH} spin spin coupling constant, we have performed the NMR spectrum analysis of some three coordinated organo-phosphorus compounds. The studied coupling constants are {sup 3}J{sub PH} through P-O-C-H and P-C-C-H fragments and {sup 2}J{sub PH} through P-C-H fragment. The results clearly show that on the NMR time scale, in all the studied compounds (1,3,2-dioxaphospholanes, 1,3,2-dioxaphosphorinanes, 3-phospha-cyclopentene and 4-phosphorinanone) there is no inversion of the bonds around phosphorous. This conclusion held also for secondary phosphines. For a given geometry of the bonds joining the P and H atoms, and a given disposition of the bonds around the phosphorus atom, there is only a little influence of the nature of the substituents on the J{sub PH} spin coupling constants. The geometrical dependence of the {sup 3}J{sub PH} cannot be explained by a 'Karplus law'. There is an influence of the bond disposition around phosphorus. In the case of the {sup 2}J{sub P-C-H}, one can plot a curve {sup 2}J{sub P-C-H} = f({alpha}) (0{<=} {alpha} {<=} 180), {alpha} denote the dihedral angle of the two plane defined the first one by the P, C and H atoms, and the second one by the P-C bond together with the three-fold axis of the bond around phosphorus assuming a regular pyramidal arrangement. The function {sup 2}J{sub P-C-H} = f({alpha}) has two maxima, one for {alpha} = 0 degrees and the other for {alpha} = 180 degrees, and also a minimum for {alpha} = 110 degrees. (author) [French] Ce travail consiste en l'analyse par resonance magnetique nucleaire des constantes de couplage phosphore-proton dans des derives organo-phosphores tricoordines dans un double but: examen de la stabilite des liaisons au niveau du phosphore et etude de l'influence de la disposition des liaisons et de la nature de substituants au

  2. Au pair trajectories

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2015-01-01

    pair-sending families in the Philippines, this dissertation examines the long-term trajectories of these young Filipinas. It shows how the au pairs’ local and transnational family relations develop over time and greatly influence their life trajectories. A focal point of the study is how au pairs...... that Filipina au pairs see their stay abroad as an avenue of personal development and social recognition, I examine how the au pairs re-position themselves within their families at home through migration, and how they navigate between the often conflicting expectations of participation in the sociality......Since 2000, thousands of young Filipino migrants have come to Denmark as au pairs. Officially, they are there to “broaden their cultural horizons” by living temporarily with a Danish host family, but they also conduct domestic labor in exchange for food and money, which allows them to send...

  3. Experimental study of mechanical behaviour of a clay-stone: application to nuclear waste disposals; Etude experimentale du comportement mecanique d'argiles raides: application au stockage de dechets radio-actifs

    Energy Technology Data Exchange (ETDEWEB)

    Chiarelli, A.S. [Laboratoire de Materiaux et Sciences des Constructions, UPRES JE 2200, IUP Genie Civil et Infrastructures, 95 - Cergy Pontoise (France); Shao, J.F. [Laboratoire de Mecanique de Lille, URA CNRS 1441, EUDIL, 59 - Villeneuve d' Ascq (France); Ledesert, B. [Laboratoire de Sedimentologie et Geodynamique, FRE 2255, 59 - Villeneuve d' Ascq (France); Hoteit, N. [Agence Nationale pour la Gestion des Dechets Nucleaires (ANDRA), 92 - Chatenay Malabry (France)

    2001-02-01

    A study of mechanical behaviour of deep argillaceous rocks from East of France, the 'argilites de l'Est' as a potential host rock for radioactive waste disposal studied by ANDRA, (french national radioactive waste management agency) is presented. Some uniaxial and triaxial compression tests with unloading-reloading cycles were realised on samples from three different depths. Important plastic strains associated to directional degradation of elastic properties show that the two principles strain mechanisms are plasticity and induced anisotropic damage. At microscopic scale, it is related to sliding of clay sheets and oriented microcracks. The influence of mineralogy is that brittle behaviour is more important with calcite while it decreases with clay. (authors)

  4. Etude de la fragmentation des partons par la mesure de corrélations photon-hadron auprès de l'expérience ALICE au LHC

    CERN Document Server

    ARBOR, Nicolas

    The strong interaction theory, Quantum Chromodynamic (QCD), predicts a new phase of nuclear matter at very high temperature and/or very high density. This state, which should have been the state of the Univers some microseconds after the Big Bang, is composed of deconfined quarks and gluons known as the quark-gluon plasma (QGP). The measurement of its composition and properties is a challenge for the nuclear physics of the 21st century and should lead to a better understanding of the fundamental symetries and mechanisms related to the quarks confinement inside hadrons and the strong interaction generally. The Large Hadron Collider (LHC) accelerator at CERN (European Organization for Nuclear Research) allows to reach the thermodynamic conditions required to create the quark-gluon plasma using ultra-relativistic heavy ion collisions (Pb). The ALICE experiment (A Large Ion Collider Experiment) allows to access several probes to characterize the QGP through particles reconstruction and. Among these probes, hi...

  5. Etude comparative de la charge parasitaire des petits ruminants et du guib harnaché dans quatre campements riverains à la forêt classée de Wari-Maro au Nord-Est du Bénin

    Directory of Open Access Journals (Sweden)

    Faihun, AML.

    2017-01-01

    Full Text Available Comparative Study of the Parasitic Load of Small Ruminants and Bushbuck in Four Camps Bordering the Wari-Maro Reserve in the North East of Benin. A comparative survey of the gastro-intestinal parasitical burden of small ruminants (sheep, goat and one species of wild ruminants (bushbuck has been conducted in four camps around the classified forest of Wari-Maro located in the North-East of Benin. The flotation and sedimentation methods, and a semi-quantitative method associated to the flotation method were used to analyze the different samples. Feces samples were collected during the dry and rainy seasons with 100 samples for sheep, 75 for goat and 25 for bushbuck. The small domestic ruminants presented six types of parasites (strongyles, Strongyloides, coccidia, tapeworm, Capillaria, trematodes. The bushbuck presented strongyles and Strongyloides only during the rainy season. The burden of different types of parasites was low in the majority of cases. The wild or domestic nature of the animal influenced its parasitical state (p<0.05. For this study it appeared that no relation exists between the infestation intensity of small ruminants and bushbuck.

  6. Contribution to the study of the readout of the electromagnetic calorimeter crystals in the CMS experiment at LHC; Contribution a l`etude de la lecture des cristaux du calorimetre electromagnetique de l`experience CMS au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Franck [Universite Claude Bernard Lyon-1, 69 - Lyon (France)

    1998-07-03

    The search for neutral Higgs boson through its decay into two photons provides a very promising signal for a mass between 90 and 150 GeV. It requires an electromagnetic calorimeter of very high resolution. The CMS (Compact Muon Solenoid) electromagnetic calorimeter must be made up of more than 80,000 lead tungstate crystals. In the central part (the barrel), the scintillation light readout is performed by means of avalanche photodiodes, a silicon photo-sensor with internal gain which is a relative novelty in high energy physics. Concerning the readout electronics, the energy available in the centre-of-mass (14 TeV) as well as the collision frequency (40 MHz) of LHC impose constraints with respect to the signal treatment up to the acquisition. The retained solution consists in pairing two avalanche photodiodes, the parameters of which (gain, temperature dependence, dark current, etc) must be controlled, and coupling them to a low noise preamplifier of high dynamical range (5 MeV - 2 TeV) followed by a four-slopes linear compressor and a analog-digital sampling converter of 12 bits, 40 MHz. The thesis presents the prototypes of different electromagnetic calorimeters tested in the high energy beam. An energy resolution of 0.6% at 100 GeV was obtained with a conventional readout circuitry, while the integrated associated circuits were radiation resistant 73 refs., 100 figs., 19 tabs.

  7. La confrontation des genres au tribunal au Moyen Âge (XIVe-XVIe siècles. Une relecture des relations de couples en conflit

    Directory of Open Access Journals (Sweden)

    Martine Charageat

    2009-12-01

    Full Text Available La conflictualité conjugale analysée avec le concept de genre, et pas seulement en vue de vérifier l’application ou non du droit matrimonial par les juges d’église, rejoint le courant davantage socio-anthropologique que juridique de l’histoire du couple en Occident au Moyen Âge. Un souffle d’optimisme historiographique provient de travaux récents, dans un champ d’étude où l’on tardait encore à apprécier la capacité des femmes à ne pas subir de tristes situations conjugales, faites de violence, de misère sentimentale et sexuelle. Il n’empêche que le conflit, au moment de sa création, son récit devant le juge, les attentes des litigants quant à sa résolution obéissent à un rapport de force entre genres clairement distingués entre eux jusque dans le choix des normes, des arguments invoqués, de la rhétorique judiciaire déployée dans les procès. Même lorsque le couple agit par collusion, le dialogue avec le juge obéit aussi à des différences de genre.The analysis of matrimonial conflicts using the concept of gender, which goes beyond the verification of whether judges applied or not canonical law, draws more on socio-anthropological trends in the history of the married couple in the middle ages than on legal trends. The new historiographical optimism present in recent works testifies to how women were able to refuse some matrimonial situations despite the existence of domestic violence, forced sexual abstinence (impotence and limited sentimental exchanges with their husbands. Nonetheless, this article highlights how gender determined the nature of every matrimonial conflict and its description before the judge. Gender underwrote as well the expectations litigants had in using lawsuits, given the power relationship between the sexes, even when wives and husbands sought  a judicial separation by mutual agreement.

  8. Relativity-Induced Bonding Pattern Change in Coinage Metal Dimers M2 (M = Cu, Ag, Au, Rg).

    Science.gov (United States)

    Li, Wan-Lu; Lu, Jun-Bo; Wang, Zhen-Ling; Hu, Han-Shi; Li, Jun

    2018-05-07

    The periodic table provides a fundamental protocol for qualitatively classifying and predicting chemical properties based on periodicity. While the periodic law of chemical elements had already been rationalized within the framework of the nonrelativistic description of chemistry with quantum mechanics, this law was later known to be affected significantly by relativity. We here report a systematic theoretical study on the chemical bonding pattern change in the coinage metal dimers (Cu 2 , Ag 2 , Au 2 , Rg 2 ) due to the relativistic effect on the superheavy elements. Unlike the lighter congeners basically demonstrating ns- ns bonding character and a 0 g + ground state, Rg 2 shows unique 6d-6d bonding induced by strong relativity. Because of relativistic spin-orbit (SO) coupling effect in Rg 2 , two nearly degenerate SO states, 0 g + and 2 u , exist as candidate of the ground state. This relativity-induced change of bonding mechanism gives rise to various unique alteration of chemical properties compared with the lighter dimers, including higher intrinsic bond energy, force constant, and nuclear shielding. Our work thus provides a rather simple but clear-cut example, where the chemical bonding picture is significantly changed by relativistic effect, demonstrating the modified periodic law in heavy-element chemistry.

  9. Etude des possibilites de contamination des aliments de rues au ...

    African Journals Online (AJOL)

    Foods poisoning due to microbial toxins are widespread throughout the world. These foods poisoning are prevalent in African countries were street alimentation enable 80% of urban populations to feed themselves easily and at lower price. The street foods constitute a major public health problem because of the multiplicity ...

  10. Etude retrospective des pathologies mentales infantiles au centre ...

    African Journals Online (AJOL)

    Motive for visit were behavioral disorders (31%) and learning difficulties (23%) among children, behavioral disorders (40%), somatic disorders (22.2%) and sleep disorders (17.7%) among adolescents. Diagnosis were psychological development disorders (30%), emotional and behavioral disorders (25%) among children, ...

  11. 40Ar-39Ar dating of Archean iron oxide Cu-Au and Paleoproterozoic granite-related Cu-Au deposits in the Carajás Mineral Province, Brazil: implications for genetic models

    Science.gov (United States)

    Pollard, Peter J.; Taylor, Roger G.; Peters, Lisa; Matos, Fernando; Freitas, Cantidiano; Saboia, Lineu; Huhn, Sergio

    2018-05-01

    40Ar-39Ar dating of biotite from IOCG and granite-related Cu-Au deposits in the Carajás Mineral Province provides evidence for the timing of mineralization and constraints on genetic models of ore formation. Ages of biotite from greisen and quartz-rich vein and breccia deposits, Alvo 118—1885 ± 4 Ma, Breves—1886 ± 5 Ma, Estrela—1896 ± 7 Ma, and Gameleira—1908 ± 7 Ma, demonstrate the close temporal relationship between Cu-Au mineralization and subjacent A-type granites. Mineralization is hosted within granite cupolas (Breves) or in vein/breccia systems emanating from the cupolas (Estrela and Gameleira), consistent with a genetic relationship of mineralization to the B-Li-F-rich granites. Plateau and minimum ages of biotite from IOCG deposits, including Igarapé Bahia, Cristalino, Corta Goela, and GT34, range from 2537 ± 6 Ma to 2193 ± 4 Ma. The 40Ar-39Ar age of biotite from Igarapé Bahia (2537 ± 6 Ma) is similar to a previous SHRIMP 207Pb-206Pb age for monazite of 2575 ± 12 Ma when the uncertainties in the respective analyses and standards are taken into account. The age spectrum for biotite from Cristalino shows increasing ages for successive steps, consistent with post-crystallization Ar loss, and the age of 2388 ± 5 Ma for the last three steps is considered a minimum age for Cu-Au mineralization. The age of biotite from the GT34 prospect (2512 ± 7 Ma) coincides with a previously identified period of basement reactivation and may indicate the formation of Cu-Au mineralization at this time or resetting of biotite from an older mineralization event at this time. At Corta Goela, within the Canaã Shear Zone, the biotite age of 2193 ± 4 Ma lies between the ages of IOCG (2.57-2.76 Ga) and granite-related Cu-Au ( 1.88 Ga) deposits elsewhere in the Carajás district but is similar to previously reported 40Ar-39Ar ages for amphibole from Sossego, possibly indicating that mineralization at both Sossego and Corta Goela was affected by a thermal event at

  12. Etude aerodynamique d'un jet turbulent impactant une paroi concave

    Science.gov (United States)

    LeBlanc, Benoit

    Etant donne la demande croissante de temperatures elevees dans des chambres de combustion de systemes de propulsions en aerospatiale (turbomoteurs, moteur a reaction, etc.), l'interet dans le refroidissement par jets impactant s'est vu croitre. Le refroidissement des aubes de turbine permet une augmentation de temperature de combustion, ce qui se traduit en une augmentation de l'efficacite de combustion et donc une meilleure economie de carburant. Le transfert de chaleur dans les au bages est influence par les aspects aerodynamiques du refroidissement a jet, particulierement dans le cas d'ecoulements turbulents. Un manque de comprehension de l'aerodynamique a l'interieur de ces espaces confinees peut mener a des changements de transfert thermique qui sont inattendus, ce qui augmente le risque de fluage. Il est donc d'interet pour l'industrie aerospatiale et l'academie de poursuivre la recherche dans l'aerodynamique des jets turbulents impactant les parois courbes. Les jets impactant les surfaces courbes ont deja fait l'objet de nombreuses etudes. Par contre des conditions oscillatoires observees en laboratoire se sont averees difficiles a reproduire en numerique, puisque les structures d'ecoulements impactants des parois concaves sont fortement dependantes de la turbulence et des effets instationnaires. Une etude experimentale fut realisee a l'institut PPRIME a l'Universite de Poitiers afin d'observer le phenomene d'oscillation dans le jet. Une serie d'essais ont verifie les conditions d'ecoulement laminaires et turbulentes, toutefois le cout des essais experimentaux a seulement permis d'avoir un apercu du phenomene global. Une deuxieme serie d'essais fut realisee numeriquement a l'Universite de Moncton avec l'outil OpenFOAM pour des conditions d'ecoulement laminaire et bidimensionnel. Cette etude a donc comme but de poursuivre l'enquete de l'aerodynamique oscillatoire des jets impactant des parois courbes, mais pour un regime d'ecoulement transitoire, turbulent

  13. Study of the production of J/{psi} in Au-Au collisions at 200 GeV per nucleon pair in the PHENIX experiment; Etude de la production du J/{psi} dans les collisions or-or a 200 GeV par paire de nucleons dans l'experience PHENIX

    Energy Technology Data Exchange (ETDEWEB)

    Tram, V.N

    2006-01-15

    One of the most promising signature of Quark Gluon Plasma formation is the heavy quarkonium suppression due to color screening effect. First experiments at the SPS (CERN) have measured an 'anomalous suppression' of the J/{psi} yields (cc-bar state) in central Pb+Pb collisions. However, measurements at different collision energies and with different ions are mandatory to conclude about the discovery of a new state of nuclear matter. This thesis describes the J/{psi} production measured in the dimuon decay channel by the PHENIX experiment (RHIC) studying Au+Au collisions at 200 GeV in the center of mass. The J/{psi} yield measured in the most central collisions is suppressed by a factor of 3 as compared to the yield expected assuming binary scaling. Within the error bars, the suppression does not affect the J/{psi}'s rapidity distribution. However, a broadening of the transverse momentum distribution is observed as compared to the distribution measured in p+p collisions. In order to understand this suppression, 'cold nuclear effects', namely nuclear absorption and shadowing, are to be taken into account. These effects can describe neither the suppression amplitude nor the suppression pattern, suggesting that other mechanisms are involved. Predictions from different models which reproduce the suppression observed by NA50, can hardly describe the PHENIX measurements and over-estimate the suppression at RHIC. Comparisons with predictions from models including recombination of charm quarks give a reasonable description of the suppression amplitude as a function of centrality. However, these predictions are not in good agreement with the observed rapidity and transverse momentum distributions. Finally, one possible scenario is that the temperature at RHIC is not high enough to reach direct J/{psi} melting and that the measured suppression is due to the sequential disappearance from higher mass resonances ({chi}{sub c} and {psi}'). In this

  14. TU-F-CAMPUS-T-02: Monte Carlo Evaluation of Kilovoltage Radiosurgery with AuNPs for Age Related Macular Degeneration (AMD)

    International Nuclear Information System (INIS)

    Brivio, D; Zygmanski, P; Sajo, E; Makrigiorgos, G; Ngwa, W

    2015-01-01

    Purpose: To evaluate the benefit of gold nanoparticles (AuNP) in radiosurgery of Age related Macular Degeneration (AMD) using Monte Carlo (MC) simulation. AMD disease causes vision loss due to a leaky vasculature of the endothelial cells. Radiosurgical therapy aims to destroy this vasculature while minimizing the delivered dose to healthy tissues of the eye. AuNP known to enhance local dose have been targeted to the macular choroidal endothelial cells to increase the therapeutic efficacy. Methods: Dose enhancement ratio (DER) in macula endothelial cells due to a thin layer of AuNP has been calculated by a MC radiation transport simulation. AuNP layer (10–100nm) has been placed on the bottom of the macula at 2.4cm depth in a water parallelepiped 3×3×6cm3. This layer has been modeled considering various concentrations of AuNP ranging from 5.5–200mg per gram of endothelial cell (volume 10×10×2um3). The x-ray source is 100kVp 4mm diameter beam tilted 0°-30° with respect to the lens. Results: DER in endothelial cell for AuNP concentration of 31mg/g (shown experimentally feasible) and 10–100nm sizes is about 1.8. Tilting 4mm-beam does not reduce the enhancement but allows to avoid the surrounding tissues. Dose distribution in the AuNP vicinity has a significant increase within 30um, peaked at AuNP interface. DER inside and outside of the irradiation 4mm-field are the same while the actual delivered dose is more than one order of magnitude lower outside the field. Compared to 100kVp, usage of filtered spectra with enhanced flux in the region 20keV-40keV shows further increase of DER by about 20%. Dose to the neighboring organs such as retina/optic nerve are reduced accordingly. Conclusion: The results of this MC simulation provide further confirmation of the potential to enhance DER with AuNP from previous analytical calculations. This study provides impetus to improve treatment effectiveness of AMD disease with radiotherapy

  15. TU-F-CAMPUS-T-02: Monte Carlo Evaluation of Kilovoltage Radiosurgery with AuNPs for Age Related Macular Degeneration (AMD)

    Energy Technology Data Exchange (ETDEWEB)

    Brivio, D; Zygmanski, P [Brigham & Women’s Hospital, Boston, MA (United States); Sajo, E [Univ Massachusetts Lowell, Lowell, MA (United States); Makrigiorgos, G [Dana Farber Cancer Institute, Boston, MA (United States); Ngwa, W [Harvard Medical School, Boston, MA (United States)

    2015-06-15

    Purpose: To evaluate the benefit of gold nanoparticles (AuNP) in radiosurgery of Age related Macular Degeneration (AMD) using Monte Carlo (MC) simulation. AMD disease causes vision loss due to a leaky vasculature of the endothelial cells. Radiosurgical therapy aims to destroy this vasculature while minimizing the delivered dose to healthy tissues of the eye. AuNP known to enhance local dose have been targeted to the macular choroidal endothelial cells to increase the therapeutic efficacy. Methods: Dose enhancement ratio (DER) in macula endothelial cells due to a thin layer of AuNP has been calculated by a MC radiation transport simulation. AuNP layer (10–100nm) has been placed on the bottom of the macula at 2.4cm depth in a water parallelepiped 3×3×6cm3. This layer has been modeled considering various concentrations of AuNP ranging from 5.5–200mg per gram of endothelial cell (volume 10×10×2um3). The x-ray source is 100kVp 4mm diameter beam tilted 0°-30° with respect to the lens. Results: DER in endothelial cell for AuNP concentration of 31mg/g (shown experimentally feasible) and 10–100nm sizes is about 1.8. Tilting 4mm-beam does not reduce the enhancement but allows to avoid the surrounding tissues. Dose distribution in the AuNP vicinity has a significant increase within 30um, peaked at AuNP interface. DER inside and outside of the irradiation 4mm-field are the same while the actual delivered dose is more than one order of magnitude lower outside the field. Compared to 100kVp, usage of filtered spectra with enhanced flux in the region 20keV-40keV shows further increase of DER by about 20%. Dose to the neighboring organs such as retina/optic nerve are reduced accordingly. Conclusion: The results of this MC simulation provide further confirmation of the potential to enhance DER with AuNP from previous analytical calculations. This study provides impetus to improve treatment effectiveness of AMD disease with radiotherapy.

  16. Comparison of Knolls Atomic Power Laboratory Clean Critical and Subcritical Experiments with Calculations; Etude Comparative des Calculs et des Experiences Critiques Non Empoisonnees et Souscritiques, Faits au Knolls Atomic Power Laboratory; Sravnenie chistykh kriticheskikh i podkriticheskikh opytov v nolle s raschetnymi dannymi; Comparacion de los Resultados Experimentales del Knolls Atomic Power Lamra Tory con los Valores Calculados Teoricamente en Conjuntos Criticos Limpios y Subcriticos

    Energy Technology Data Exchange (ETDEWEB)

    Bach, D. R.; Bistline, J. A.; Bunch, S. I.; Cerbone, R. J.; Feiner, F.; Skolnik, W.; Slovacek, R. E.; Weinstein, S. [Knolls Atomic Tower Laboratory, Schenectady, NY (United States)

    1964-02-15

    At the Knolls Atomic Power Laboratory an intensive programme of experimentation and related calculations has been underway to assess the adequacy of computational methods and nuclear data for hydrogenous systems. The programme has three general aspects: (1) Clean critical experiments with solid homogeneous fuel having a high metal-to-hydrogen volume ratio; (2) clean, plate-fuel critical experiments covering a large range of core dimension, metal-to-water ratio, fuel density and temperature; (3) prompt-neutron decay constant and steady-state spectrum measurements on subcritical systems in the same range of composition. The fuel elements for the solid homogeneous experiments are pressed compacts of ZrO{sub 2}, and highly enriched UO{sub 2}, powders uniformly mixed with paraffin. Reflector blocks With the same ZrO{sub 2}-to-paraffin ratio as the fuel blocks allow reflected cores to be constructed having uniform slowing down characteristics. The mechanics of the critical assembly are such that critical configurations are simple rectangular parallelepipeds with no channels for safety or control rods. Critical size studies of fast-leakage dominated systems (bare and reflected) have been performed and comparisons made with standard two-and three-dimensional, few-group computer programmes. In general the calculated criticality constants using the most recent nuclear data are about 3% high. The plate experiments described covered the range from room temperature to 560 Degree-Sign F and 1200 psi. To eliminate the complication of control-rod effects a determination of the temperature at which the core was critical was made with the control rods almost completely withdrawn. With the currently available crosssection information the calculated criticality is consistently high by about 2% over the whole range of experiments. Calculations of the decay constants made by the 1/v poison removal technique using standard few-group diffusion codes employing group-dependent boundary

  17. Contribution to the study of french pitchblendes; Contribution a l'etude des pechblendes francaises

    Energy Technology Data Exchange (ETDEWEB)

    Geffroy, J [Commissariat a l' Energie Atomique, Lab. de Mineralogie, Centre de Chatillon (France). Centre d' Etudes Nucleaires; Sarcia, J A [Commissariat a l' Energie Atomique, Div. de la Crouzille, Haute Vienne (France). Centre d' Etudes Nucleaires

    1955-07-01

    The authors first review the characteristics of uraninite-pitchblende, as deduced of present literature. They set apart from typical pitchblende a black oxide aspect, which probably corresponds to neo-formations, and a 'para-pitchblende' aspect, which they relate to deep sur-oxidation of normal pitchblende. They insist on the easy replacement of pitchblende by silica. and give indications as to changes in vein stones (fluorite, quartz, etc...). A detailed study of paragenesis and successions in french uranium districts follows (including discussion of uranium of uranium-bearing coals). The authors attempt to classify french pitchblende veins. They are chiefly epithermal and poor in satellite ores. Three types of deposits are identified: massive - pitchblende type, silica type, fluorite type. These deposits, as those of Portugal, are included in granite, Central-European peri-batholitic types where uranium associates which Ni, Co, Bi and Ag, are in France both rare and poor. Finally, the authors attempt to bring out in the european Hercynian area a particular distribution of paragenetic types. (authors) [French] Les auteurs recapitulent d'abord les caracteres et les occurences de l'uraninite - pechblende, tels qu'ils peuvent etre degages de l'actuelle bibliographie. Ils exposent ensuite les faits qui du point de vue mineralogique seulement ressortent de l'etude mineralogique et chalcographique des pechblendes francaises et de leurs satellites. Ils distinguent de la pechblende-type un facies oxyde noir; correspondant probablement a une neoformation, et un facies parapechblende, qui est rapporte a une sur oxydation hypogene de la pechblende proprement dite. Ils insistent sur le facile remaniement de la pechblende par la slice; et donnent quelques precisions sur les modifications des gangues (fluorine, quartz, etc...). Suit l'etude detaillee des parageneses et des successions dans les districts uraniferes francais: Divisions du Limousin, de Grury, de Lachaux et de

  18. Fragmentation of massive dense cores down to ≲ 1000 AU: Relation between fragmentation and density structure

    International Nuclear Information System (INIS)

    Palau, Aina; Girart, Josep M.; Estalella, Robert; Fuente, Asunción; Fontani, Francesco; Sánchez-Monge, Álvaro; Commerçon, Benoit; Hennebelle, Patrick; Busquet, Gemma; Bontemps, Sylvain; Zapata, Luis A.; Zhang, Qizhou; Di Francesco, James

    2014-01-01

    In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.

  19. Fragmentation of massive dense cores down to ≲ 1000 AU: Relation between fragmentation and density structure

    Energy Technology Data Exchange (ETDEWEB)

    Palau, Aina; Girart, Josep M. [Institut de Ciències de l' Espai (CSIC-IEEC), Campus UAB-Facultat de Ciències, Torre C5-parell 2, E-08193 Bellaterra, Catalunya (Spain); Estalella, Robert [Departament d' Astronomia i Meteorologia (IEEC-UB), Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès, 1, E-08028 Barcelona (Spain); Fuente, Asunción [Observatorio Astronómico Nacional, P.O. Box 112, E-28803 Alcalá de Henares, Madrid (Spain); Fontani, Francesco; Sánchez-Monge, Álvaro [Osservatorio Astrofisico di Arcetri, INAF, Lago E. Fermi 5, I-50125 Firenze (Italy); Commerçon, Benoit; Hennebelle, Patrick [Laboratoire de Radioastronomie, UMR CNRS 8112, École Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Busquet, Gemma [INAF-Istituto di Astrofisica e Planetologia Spaziali, Area di Recerca di Tor Vergata, Via Fosso Cavaliere 100, I-00133 Roma (Italy); Bontemps, Sylvain [Université de Bordeaux, LAB, UMR 5804, F-33270 Floirac (France); Zapata, Luis A. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, P.O. Box 3-72, 58090 Morelia, Michoacán (Mexico); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Di Francesco, James, E-mail: palau@ieec.uab.es [Department of Physics and Astronomy, University of Victoria, P.O. Box 355, STN CSC, Victoria, BC, V8W 3P6 (Canada)

    2014-04-10

    In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.

  20. Spécialiste en relations de travail et en santé et sécurité au travail (h ...

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

    Résumé des fonctions. Le spécialiste en relations de travail et en santé et sécurité au travail fournit des conseils et des services d'expert en ce qui concerne les relations de travail qui visent à établir, à mettre en oeuvre et à entretenir une relation de travail productive avec les employés et leurs représentants syndicaux.

  1. Nuclear fragmentation for Xe+Au and Xe+Ag systems at an energy of 44 A.MeV, formation and decay of hot nuclei; Etude de la fragmentation nucleaire pour les systemes XE+AU et XE+AG a 44 A.MeV, production et decroissance de noyaux chauds

    Energy Technology Data Exchange (ETDEWEB)

    Meslin, C.

    1995-01-01

    A study of the formation and the decay of hot nuclear fragments produced in the reactions Xe+Au and Xe+Ag at an energy of 44 A.MeV is presented in this thesis. The 4{pi} experimental setup consisted of four multidetectors -two for the detection of the fragments (Z>7; DELF and XYZT) and two for the detection of the charged particles (Z<6; MUR and TONNEAU) and allowed an analysis using ``complete events`` (80 % of the total charge and the total parallel linear momentum of the entrance channel) to be carried out. The reaction mechanism is binary with as observed at low energy an almost complete relaxation of the incident energy. The collision results in two hot fragments at the beginning of the exit channel which decay by evaporation and/or fragmentation. In addition of these two body events, we have identified a new dynamic mechanism where we detect a small fragment, called the neck, coming form the overlap of the nuclei during the interaction, in coincidence with a projectile-like fragment and a target-like fragment. For the most dissipative collisions, the deep inelastic collision have allowed an estimation of the lifetime of the hot nuclear fragments to be made. This is possible using proximity effects and fragment-fragment space-time correlations of the decay of one or two primary partners from the deep inelastic collisions. This method is seen to reach its limits in the case of the reactions studied here. (authors). 61 refs.

  2. Study of the reactions resulting in heavy fragment formation in the collisions {sup 40}Ar + Cu, Ag and Au at 8 to 115 MeV/u; Etude des reactions avec formation d`un fragment lourd dans les collisions {sup 40}Ar + Cu, Ag et Au de 8 a 115 MeV/u

    Energy Technology Data Exchange (ETDEWEB)

    Colin, Eric Yves [Universite Claude Bernard Lyon-1, 69 - Lyon (France)

    1998-11-06

    This work concerns the study of nuclear collisions showing a heavy fragment in {sup 40}Ar + Cu, Ag and Au from 8 A MeV to 115 A MeV. The reactions are classified by centrality or collision violence via the multiplicity of charged particles detected in a 4{pi} array. For the most peripheral reactions (low multiplicities) we always find a projectile-like fragment with velocity near to that of the beam and a heavy target-like fragment with very small velocity. For the more central collisions we find the well-known incomplete fusion reactions at 17 and 27 A MeV. Above 27 A MeV two groups of very dissipative reactions are observed, both with high charged particle multiplicities. The first reaction group forms several fragments with Z {<=} 10 and average longitudinal velocity near to that of c.m. These are very rare, and are found only for the highest 1% of multiplicities. They produce a heavy fragment and a forward spray ({theta}{<=}60 angle) of particles with charge going from 1 to {approx_equal}13. The momentum carried out by the spray is randomly spread over all the particles. In spite of the increase of momentum carried by this spray with increasing beam energy, a heavy emission source is formed with 1 - 2 GeV of excitation energy. After a phase of expansion, especially signaled by Z = 1 particles, this source then evaporates many particles. Finally we observed the remaining heavy residual nucleus. (author) 117 refs., 85 figs., 12 tabs.

  3. Technical Developments in the USAEC Process Radiation Development Program; Etudes technologiques dans le cadre du programme de mise au point d'applications industrielles des rayonnements de la CEA-EU; Issledovaniya v oblasti promyshlennogo primeneniya izluchenij, vkhodyashchie v programmu komissii po atomnoj ehnergii USAEC; Progresos tecnicos en el programa de la USAEC para el fomento de la irradiacion industrial

    Energy Technology Data Exchange (ETDEWEB)

    Machurek, J. E.; Stein, M. H. [Division of Isotopes Development, USAEC, Washington, DC (United States)

    1963-11-15

    des rayonnements ionisants. Les auteurs donnent les resultats de quatorze de ces travaux; certains sont decrits succinctement dans le memoire et d'autres sont exposes en detail dans les comptes rendus. Les sujets traites sont les suivants: 1. Preparation de produits bois-matiere plastique en utilisant des rayons gamma pour induire la polymerisation. 2. Emploi du rayonnement beta des produits de fission pour l'hydrogenation de la houille et de ses derives pour produire des hydrocarbures liquides. 3. Production de semi-conducteurs dans lesquels on repartit les impuretes selon un schema spatial fixe a l'avance, a l'aide de transmutations neutroniques. 4. Polymerisation radioinduite de l'ethylene et de ses copolymeres. 5. Etude fondamentale du mecanisme et de la cinetique des reactions radioinduites. 6. La. radiochimie dans la fluoration de divers composes aromatiques. 7. Emploi de monomeres polyfonctionnels pour augmenter la radioreticulation du polyethylene, du polypropylene, du polyisobutylene et de l'acetate de cellulose. 8. Effets du gonflement, des contraintes et d e la temperature sur les proprietes physiques et chimiques des polymeres produits au moyen des rayonnements. 9. Influence des facteurs structurels sur les modifications radioinduites dans les polymeres conduisant a la copolymerisation par greffage. 10. Utilisation des rayonnements pour modifier les proprietes de matieres textiles. 11. Reactions radioinduites utilisant le krypton-85. 12. Preparation d'un ''Manuel des rayonnements''. 13. Utilisation de la liaison organometallique en dosimetrie des rayons gamma intenses. 14. Mise au point d'un dosimetre a cellule solaire. (author) [Spanish] Dentro del marco de su programa de fomento de la irradiacion industrial, la Comision de Energia Atomica de los Estados Unidos ha emprendido una amplia serie de investigaciones cuyo objetivo principal es estimular un progreso tecnologico que facilite el empleo de las radiaciones ionizantes en la produccion industrial. Los

  4. 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)

  5. The gold-rich indide Eu{sub 5}Au{sub 17.7}In{sub 4.3} and its relation with the structures of SrAu{sub 4.76}In{sub 1.24} and BaLi{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Muts, Ihor [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Ivan Franko National Univ. of Lviv (Ukraine). Inorganic Chemistry Dept.; Rodewald, Ute C.; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Zaremba, Vasyl' I.; Pavlosyuk, Orest [Ivan Franko National Univ. of Lviv (Ukraine). Inorganic Chemistry Dept.

    2012-02-15

    The gold-rich indide Eu{sub 5}Au{sub 17.7}In{sub 4.3} was synthesized from the elements in a sealed tantalum ampoule that was heated in a high-frequency furnace. Eu{sub 5}Au{sub 17.7}In{sub 4.3} crystallizes with a new monoclinic structure type: C2/m, a = 902.7(2), b = 722.8(3), c = 1734.1(4) pm, {beta} = 94.31(3) , wR2 = 0.0907, 2640 F{sup 2} values and 74 variables. Eu{sub 5}Au{sub 17.7}In{sub 4.3} has a pronounced gold substructure with Au.Au distances ranging from 278 to 300 pm. The striking structural motifs in the gold substructure are networks of Au6 hexagons and discrete units of corner- and edge-sharing Au{sub 4} tetrahedra. Eu{sub 5}Au{sub 17.70}In{sub 4.30} exhibits a small homogeneity range with In/Au mixing on two Wyckoff sites. Geometrically, the Eu{sub 5}Au{sub 17.7}In{sub 4.3} structure can be explained as an intergrowth variant of slightly distorted SrAu{sub 4.76}In{sub 1.24}- and BaLi{sub 4}-related slabs. The europium coordination in the BaLi{sub 4} slabs is similar to binary EuAu{sub 2}. (orig.)

  6. A Survey of the Fuel Cycles Operated in the United Kingdom; Etude d'ensemble sur les cycles de combustible au Royaume-Uni; Obzor toplivnykh tsiklov, ispol'zuemykh v soedinennom korolevstve; Estudio de los ciclos de combustible utilizados en el Reino Unido

    Energy Technology Data Exchange (ETDEWEB)

    Allday, C. [United Kingdom Atomic Energy Authority, Risley, Warrington, Lancs (United Kingdom)

    1963-10-15

    son programme d'energie d'origine nucleaire sur la filie re des reacteurs a l'uranium naturel et au graphite, refroidis par un gaz. Les reacteurs de Calder Hall et de Chapelcross fonctionnent depuis sept ans; ceux de Berkeley et de Bradwell, qui dependent du Central Electricity Generating Board (CEGB), sont maintenant en service et sept autres reacteurs sont en construction ou en projet. Le combustible destine a ces reacteurs est etudie et fabrique dans l'usine de l'Atomic Energy Authority (AEA) a Springfields, puis transporte jusqu'au reacteur. Apres irradiation et dechargement, le combustible est transporte a l'usine de l'AEA, situee a Windscale, ou l'uranium et le plutonium sont separes des produits de fission. L'auteur decrit l'experience britannique en matiere d'etude et de fabrication du combustible, d'exploitation du reacteur, de transport et de traitement chimique du combustible irradie. Il examine brievement le comportement du combustible dans le reacteur et les differents programmes possibles de chargement et de dechargement, ce sujet etant developpe dans un autre memoire. b) Reacteurs utilisant les combustibles enrichis. Le Royaume-Uni met au point un reacteur perfectionne refroidi par un gaz (Advanced Gas Cooled Reactor = AGR), dont le prototype a ete mis en service en 1963. Le combustible est fabrique a partir d'oxyde d'uranium enrichi gaine d' acier inoxydable; apres irradiation, il sera traite dans une novelle installation qui sera ajoutee a l'usine de separation de Windscale ou est actu ellement traite le combustible gaine de magnox. L'uranium enrichi destine a AGR est produit par l'usine de diffusion situee a Capenhurst. L'oxyde d'uranium naturel enrichi au plutonium peut remplacer, comme combustible, l'oxyde d'uranium enrichi. L'auteur decrit l'experience acquise dans la transformation de l'oxyde destine a AGR et dans le fonctionnement du reacteur et indique comment on envisage de traiter le combustible irradie. Il examine le cas de l'utilisation d

  7. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    Science.gov (United States)

    Bendaoud, Adlane Larbi

    . Dans la partie theorique, un modele traitant les aspects thermique, hydrodynamique et massique a ete elabore. Sur la base de ce modele a ete ecrit un programme informatique en langage FORTRAN 6.6. Il est base sur la discretisation du serpentin en volumes de controle, est entierement automatise et peut traiter des echangeurs de chaleur avec des circuits de refrigerant complexes pouvant avoir des entrees et sorties multiples ainsi que des bifurcations. La presence simultanee des trois phases thermodynamiques du refrigerant (liquide sous refroidi, fluide sature, vapeur surchauffee) dans le serpentin est aussi prise en charge. Le modele a ete valide pour un fonctionnement avec et sans formation de givre en utilisant des donnees experimentales disponibles dans la litterature et celles obtenues sur le banc d'essai de CanmetENERGIE. Celui-ci a ete mis a jour pour les besoins de la presente recherche et pour cela, un systeme de surchauffe et d'injection de la vapeur d'eau dans une enceinte a tres basse temperature a ete dimensionne, fabrique et installe. Un dispositif de visualisation de la formation de givre, ainsi qu'un equipement de mesure de la temperature, de la pression et de l'humidite relative de l'air ont aussi ete ajoutes. Une fois le modele valide, des simulations numeriques sur le serpentin avec et sans formation de givre ont ete effectuees. Un premier cas de base a servi comme reference pour d'autres cas pour lesquels une etude parametrique sur la geometrie et le fonctionnement a ete menee. Il a ete montre par rapport au cas de base que : 1. la diminution de la densite des ailettes sur des rangees specifiques du serpentin donne une surface minimale (Amin) plus grande, retardant ainsi l'obstruction totale du serpentin par le givre et permet donc un temps de fonctionnement plus grand et une frequence de degivrage plus faible. 2. une bonne configuration de circuit de refrigerant augmente le temps de fonctionnement du serpentin de 200 % et delivre une puissance

  8. Road traffic,NO{sub 2} exposure and respiratory system of the child in the VESTA study; Trafic automobile, exposition au NO{sub 2} et fonction respiratoire de l'enfant au sein de l'etude VESTA

    Energy Technology Data Exchange (ETDEWEB)

    Gauvin, St.; Amro, S.; Zmirou, D. [Faculte de Medecine, Lab. de Sante Publique, 38 - La Tronche (France); Le Moullec, Y. [Lab. d' Hygiene de la Ville de Paris, 75 (France); Sahraoui, F. [Hopital Trousseau, 75 - Paris (France); Pin, I. [Centre Hospitalier Universitaire 1-Michallon, 38 - Grenoble (France); Neukirch, F. [INSERM U 408, Faculte de Medecine Xavier Bichat, 75 - Paris (France); Momas, I. [Faculte de Pharmacie, Lab. d' Hygiene et Sante Publique, 75 - Paris (France); Lauvergne, N. [Centre Hospitalier Universitaire de l' Archet, 06 - Nice (France); Poilve, M.P. [Centre Hospitalier Universitaire Purpan, 31 - Toulouse (France); Chiron, M. [Institut National de Recherche sur les Transports et leur Securite (INRETS), 69 - Bron (France)

    2000-07-01

    The purpose of VESTA study is to assess the role of air pollution associated with automobile exhaust on the occurrence of childhood asthma. A case-control study is underway in 4 French cities (Paris, Grenoble, Toulouse and Nice). Cases are 'incident' asthmatics (less than 2 years since first diagnostic); controls are non asthmatic children chosen at random among a pool of relatives of the cases, after provision for overmatching on home location. The children, 4 to 14 years of age at inclusion, must fill in questionnaires that describe their past and present life environment. They also must carry during 48 hours passive monitors for NO and NO{sub 2}. This paper deals with the association between the respiratory function, measured at the enrollment of children, and personal NO{sub 2} exposure or proximity of their home and school to traffic. This work also allows assessment of the relative contribution of different emissions sources on personal NO{sub 2} exposure. The respiratory function (FEVI and PEFR) was measured with a One-Flow tester, a portable electronic device. NO{sub 2} personal exposure was measured by passive Ogawa samplers continuously worn during 48 hours. Exposure to traffic exhausts was assessed through an index based on a time-weighted average of the traffic density to road distance ratio (I/D), where I and D were calculated for the home and school addresses. Time spent daily at home and at school, as documented by the time activity diary, was used for weighing the school and home I/D ratios. The most influential variables that predicted NO{sub 2} personal exposures were the traffic index, the use of a gas cooker at home and the background pollution (partial R2 ranks from 0.33 to 067). No association was found between the respiratory function and the levels of NO{sub 2} personal exposure. Nevertheless, the FEVI or PEFR values were associated to traffic index, in 2 out of 4 cities. These results suggest that exposure to traffic exhausts may

  9. Study and construction of a {beta}-spectrometer of uniform axial magnetic field fitted with a {beta}-{gamma} coincidence selector. Study of the {beta} spectra of {sup 32}P, {sup 203}Hg, {sup 198}Au. Measurement of the conversion coefficients of {sup 203}Ti and of {sup 198}Hg; Etude et realisation d'un spectrometre-{beta} a champ magnetique axial uniforme, muni d'un selecteur de coincidence {beta}-{gamma}. Etude des spectres {beta} du {sup 32}p, {sup 203}Hg, {sup 198}Au. Mesure des coefficients de conversion du {sup 203}Ti et du {sup 198}Hg

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-06-01

    various elements of the matrix. (author) [French] Dans une premiere partie est rappele le principe du spectrometre beta a champ axial uniforme en employant systematiquement la notion de caustique. L'appareil est decrit et ses proprietes comparees a celles deduites du calcul des trajectoires. Les detecteurs des rayons beta et des rayons gamma et le dispositif de selection des co cidences avec une resolution 2 {tau} de 5 nanosecondes sont egalement presentes. Dans une seconde partie, le spectrometre est employe a l'etude de corps de reference et on confirme les resultats obtenus avec la meilleure precision. Le spectre beta du {sup 60}Co a la forme statistique avec une precision de 1 pour cent, l'energie maximale E{sub 0} est de 316,5 {+-} 1,5 keV. Celui de la transition 7/2 + {yields} 11/2 du {sup 137}Cs possede la forme unique, une fois interdite. E{sub 0} = 522 {+-} 3 keV. Coefficients de conversion {alpha}{sub k} = 96 {+-} 1 X 10{sup -3} {alpha}L + M + N 20,9 {+-} 0,5 X 10{sup -3}. Les deux spectres beta du {sup 59}Fe, separes par coincidence avec le gamma ont la forme statistique E{sub 0} = 462 {+-} 2 keV (55,1 + 0,3 pour cent) et E{sub 1} = 275 {+-} 4 keV (44,9 {+-} 0,3 pour cent). On se propose ensuite d'examiner si la regle de selection l se manifeste dans la forme du spectre beta du phosphore 32. On constate, en effet, qu'elle s'ecarte de la forme statistique et on determine son coefficient de forme. L'interpretation theorique exige l'emploi de meilleures approximations que celles habituellement employees et elle n'est pas unique. Cette etude permet egalement de mettre en evidence la legere proportion de {sup 33}P que contient la source. L'etude du spectre beta de {sup 203}Hg suivi du gamma de 279 keV a pour but de determiner les coefficients de conversion. Le spectre interieur de l'or 198 n'a pas non plus la forme statistique. Le coefficient de forme est determine ainsi que les coefficients de conversion qui presentent un leger desaccord avec ceux calcules par Rose

  10. Study and construction of a {beta}-spectrometer of uniform axial magnetic field fitted with a {beta}-{gamma} coincidence selector. Study of the {beta} spectra of {sup 32}P, {sup 203}Hg, {sup 198}Au. Measurement of the conversion coefficients of {sup 203}Ti and of {sup 198}Hg; Etude et realisation d'un spectrometre-{beta} a champ magnetique axial uniforme, muni d'un selecteur de coincidence {beta}-{gamma}. Etude des spectres {beta} du {sup 32}p, {sup 203}Hg, {sup 198}Au. Mesure des coefficients de conversion du {sup 203}Ti et du {sup 198}Hg

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-06-01

    various elements of the matrix. (author) [French] Dans une premiere partie est rappele le principe du spectrometre beta a champ axial uniforme en employant systematiquement la notion de caustique. L'appareil est decrit et ses proprietes comparees a celles deduites du calcul des trajectoires. Les detecteurs des rayons beta et des rayons gamma et le dispositif de selection des co cidences avec une resolution 2 {tau} de 5 nanosecondes sont egalement presentes. Dans une seconde partie, le spectrometre est employe a l'etude de corps de reference et on confirme les resultats obtenus avec la meilleure precision. Le spectre beta du {sup 60}Co a la forme statistique avec une precision de 1 pour cent, l'energie maximale E{sub 0} est de 316,5 {+-} 1,5 keV. Celui de la transition 7/2 + {yields} 11/2 du {sup 137}Cs possede la forme unique, une fois interdite. E{sub 0} = 522 {+-} 3 keV. Coefficients de conversion {alpha}{sub k} = 96 {+-} 1 X 10{sup -3} {alpha}L + M + N 20,9 {+-} 0,5 X 10{sup -3}. Les deux spectres beta du {sup 59}Fe, separes par coincidence avec le gamma ont la forme statistique E{sub 0} = 462 {+-} 2 keV (55,1 + 0,3 pour cent) et E{sub 1} = 275 {+-} 4 keV (44,9 {+-} 0,3 pour cent). On se propose ensuite d'examiner si la regle de selection l se manifeste dans la forme du spectre beta du phosphore 32. On constate, en effet, qu'elle s'ecarte de la forme statistique et on determine son coefficient de forme. L'interpretation theorique exige l'emploi de meilleures approximations que celles habituellement employees et elle n'est pas unique. Cette etude permet egalement de mettre en evidence la legere proportion de {sup 33}P que contient la source. L'etude du spectre beta de {sup 203}Hg suivi du gamma de 279 keV a pour but de determiner les coefficients de conversion. Le spectre interieur de l'or 198 n'a pas non plus la forme statistique. Le coefficient de forme est determine ainsi que les coefficients de conversion

  11. An approach to automated chromosome analysis; Etudes pour une methode d'automatisation des analyses chromosomiques

    Energy Technology Data Exchange (ETDEWEB)

    Le Go, Roland

    1972-05-03

    d'une automatisation des differentes etapes de l'analyse chromosomique. Il est divise en trois tomes dont la matiere est decrite ci-apres. Dans le tome 1 est decrite l'etude d'un selecteur automatique de metaphases. Cet appareil doit realiser au cours du scanning d'une preparation, un processus de decision aboutissant a rejeter toutes images ininteressantes et a conserver les images pertinentes (bonnes metaphases). Ce probleme a ete aborde au moyen d'une etude sur ordinateur par un programme de simulation. La realisation de ce programme a permis d'etablir des algorithmes de selection dont la replique pourra etre realisee dans des circuits logiques electroniques. Dans le tome 2 est traite le probleme de l'automatisation de l'etude morphologique des chromosomes presents dans une metaphase. Cette automatisation necessite le traitement des photographies de metaphases par un appareil convertisseur optique-numerique qui extrait l'information-image et la transcrit sous la forme d'un fichier numerique. Ce fichier comporte pour une image de metaphase, environ 200 000 valeurs de gris, codees selon une echelle a 16, 32 ou 64 ni veaux. Ce fichier numerique est traite par un programme de reconnaissance de forme, qui isole les chromosomes et en recherche les traits caracteristiques: sommets de bras et region centromerique, dans le but d'obtenir des mensurations equivalentes aux longueurs des quatre bras. Le tome 3 etudie un programme d'etablissement automatique du caryotype humain, par appariement optimise des chromosomes. Les donnees proviennent de la numerisation directe des longueurs de bras, effectuee au moyen d'un lecteur digital BENSON. Le programme etablit une liste des appariements, un document graphique imprime representant les paires constituees, dans l'espace: longueur - index centromerique; enfin un document graphique obtenu sur traceur BENSON dans lequel l'auteur donne une representation personnelle des chromosomes, sous forme de croix a bras orthogonaux, dont chaque

  12. Des atomes d'antihydrogene produits en quantites substantielles au CERN

    CERN Multimedia

    Sevestre, G

    2002-01-01

    "Des quantites relativement substantielles d'atomes d'antihydrogene a basse temperature ont ete produites cet ete au Laboratoire europeen de physique des particules, le CERN a Geneve, ouvrant la voie a une etude approfondie de cette antimatiere qui pourrait remettre en cause les theories actuelles, a annonce mercredi sur le site Internet de la revue Nature une equipe internationale de chercheurs" (1 page).

  13. Etude de la relation entre le scolyte des rameaux du cafeier, Xyleborus compactus Eichh. (X. morstatti Hag.), et sa plante-hote

    NARCIS (Netherlands)

    Brader, L.

    1964-01-01

    The mutual relation between the coffee-twig beetle, an ambrosia beetle, and the coffee plant was analysed as an example of the relation between insect and host plant. By boring passages in the twigs of the coffee plant, the beetle killed the twigs. Control was hindered by the feeding of the beetle

  14. Use of Radioactive Tracers in the Study of Insect-Plant Relationships; Emploi des radioindicateurs dans l'etude des relations insecte-plante; Ispol'zovanie radioaktivnykh indikatorov dlya izucheniya vzaimnoj svyazi mezhdu nasekomymi ch rasteniyami; Empleo de marcadores radiactivos para estudiar las relaciones insecto-planta

    Energy Technology Data Exchange (ETDEWEB)

    Crossley, Jr., D. A. [Radiation Ecology Section, Health Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1963-09-15

    by an entire insect community. Similarly, the utilization of insects as food by predaceous arthropods was estimated from steady-state concentrations of radiocaesium in predators and prey, biomasses, and an average elimination rate. (author) [French] Dans les premiers travaux ecologiques sur les insectes nuisibles effectues a l'aide de radioindicateurs, les chercheurs ont etudie les phenomenes de dispersion et de migration en utilisant les radioisotopes pour le marquage d'individus. Plus recemment, ils s'en sont servis pour etudier les relations insecte-plante et predateur-proie, en procedant a des evaluations de l'utilisation des aliments. L'elimination biologique des radioisotopes, qui constitue un inconvenient dans les etudes sur la dispersion, est utilisee dans ce cas comme mesure des taux d'alimentation. Dans les experiences en plein champ ou en laboratoire, on attend que la concentration des radioisotopes ingeres par les insectes parvienne a l'equilibre. Le taux d'absorption des radiosotopes est alors egal a leur taux d'elimination: (taux d'ingestion) = (quantite a l'equilibre) x (taux de pertes fractionnaire). Les mesures des taux d'elimination (periode biologique) permettent de traduire les concentrations a l'equilibre en fonctions exprimant les taux d'ingestion. Les auteurs ont procede a des etudes sur la consommation d'aliments dans des populations composees d'une seule espece d'insectes et dans des populations composees de plusieurs especes. Dans une etude en plein champ sur une seule espece, ils ont procede au marquage par le radiocesium afin d'evaluer la consommation de feuilles de saule par des populations de chrysomeles (Chrysomela knabi). Les mesures directes de la consommation d'aliments faites en laboratoire ont bien concorde avec les evaluations des taux d'alimentation faites en plein champ au moyen des methodes radioisotopiques. Les periodes biologiques ont ete differentes pour les stades larvaires, qu'il a fallu etudier separement. Les

  15. Studies of iron carbon alloys; Contribution a l'etude des alliages dilues de carbone dans le fer {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Anagnostopoulos, T [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1971-07-01

    Precipitation of carbon in {alpha} iron during a thermal treatment was followed using the magnetic after effect. A study was made of the influence of different parameters such as quenching speed, annealing rate, carbon concentration with or without impurity, irradiation effects. A transient sur-saturation occurs during dissolution of carbon in iron at 500 C. (author) [French] La precipitation du carbone dans le fer au cours d'un traitement thermique a ete suivie au moyen du trainage magnetique. L'etude de differents parametres tels que: vitesse de trempe, mode de recuit, concentration en carbone, presence d'impuretes, effet d'une irradiation, ont ete menes a bien. Un phenomene de sursaturation transitoire au cours de la remise en solution a 500 C a ete mis en evidence. (auteur)

  16. Etude empirique de la relation entre le système monétaire et financier et la croissance économique

    OpenAIRE

    Ouni, Moez; Nejadan-Zarin, Milad

    2011-01-01

    La problématique de la relation entre le système financier, et de ses effets, et la croissance économique reste une question controversée. Elle est sujet d’un débat animé entre les différentes tendances économiques. L’objectif de la présente thèse est d’apporter des éclairages sur la nature de ladite relation. Pour atteindre cet objectif, Nous avons considéré le système financier composé du système bancaire, y compris la banque centrale, et de la bourse de valeurs, et la croissance économique...

  17. ETUDE - European Trade Union Distance Education.

    Science.gov (United States)

    Creanor, Linda; Walker, Steve

    2000-01-01

    Describes transnational distance learning activities among European trade union educators carried out as part of the European Trade Union Distance Education (ETUDE) project, supported by the European Commission. Highlights include the context of international trade union distance education; tutor training course; tutors' experiences; and…

  18. Development of a semiconductor counter telescope with low background for the investigations of charged particles produced in reactions induced by neutrons; Realisation et mise au point d'un telescope a semi-conducteurs et a faible bruit-de-fond pour l'etude des reactions neutronsparticules chargees

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-08-15

    A AE-E counter telescope for charged particles (p, d, t) produced in reactions with neutrons has been constructed. The semiconductor counter telescope method allows the investigations of two and three-body reactions {sup 6}Li(n,p), D(n,np)n induced by 14 MeV neutrons. By using a coincidence of associated alpha particle pulses with those ({delta}E,E) in the telescope, the background is considerably reduced for all angles outside the coincidence cone, i.e. larger than 15 deg. (L). For forward angles, the same telescope ({delta}E{sub 2}/E) plus a thin semiconductor ({delta}E{sub 1}) allows keeping a low background. The multiparameter analysing method ({delta}E{sub 1}, {delta}E{sub 2}, E) from the experimental range-energy data gives a linearity, an efficiency and an identifying power which are satisfactory. The identification is performed by differed time on a IBM 7044 computer. (author) [French] On a realise un spectrometre de particules chargees (p, d, t) avec identification des particules, pour l'etude des reactions neutrons-particules chargees. La methode du telescope a semi-conducteurs permet d'effectuer l'etude de reactions a deux corps [{sup 6}Li(n,p)] et de reactions a trois corps [D(n,pn)n] a 14 MeV. L'utilisation de la particule alpha associee en coincidence avec les impulsions ({delta}E,E) du telescope permet d'obtenir un bruit-de-fond tres faible pour tous les angles situes en dehors du cone de coincidence, c'est-a-dire superieurs a {approx_equal} 15 deg. (L). Pour les angles avant, le meme telescope ({delta}E{sub 2}/E) plus un semi-conducteur mince ({delta}E{sub 1}) permet de conserver un faible bruit-de-fond. La methode d'analyse multiparametrique ({delta}E{sub 1}, {delta}E{sub 2}, E) a partir des donnees experimentales parcours-energie, donne une linearite, une efficacite et un pouvoir d'identification satisfaisants. L'identification est effectuee en temps differe sur un calculateur numerique IBM 7044. (auteur)

  19. Contribution to the study of the {sup 31}P, {sup 1}H spin spin coupling constant N. M. R. in three co-ordinated phosphorus compounds. Influence of the bond orientation and of the nature of the substituent around the phosphorus atom; Contribution a l'etude des constantes de couplage {sup 31}P, {sup 1}H en R.M.N. dans les composes organo-phosphores tricoordines. Influence des facteurs geometriques et de la nature des substituants au niveau du phosphore

    Energy Technology Data Exchange (ETDEWEB)

    Robert, J.B. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    In order to investigate the influence of the configuration at the phosphorus atom and the influence of the substituents attached to the phosphorus atom on the J{sub PH} spin spin coupling constant, we have performed the NMR spectrum analysis of some three coordinated organo-phosphorus compounds. The studied coupling constants are {sup 3}J{sub PH} through P-O-C-H and P-C-C-H fragments and {sup 2}J{sub PH} through P-C-H fragment. The results clearly show that on the NMR time scale, in all the studied compounds (1,3,2-dioxaphospholanes, 1,3,2-dioxaphosphorinanes, 3-phospha-cyclopentene and 4-phosphorinanone) there is no inversion of the bonds around phosphorous. This conclusion held also for secondary phosphines. For a given geometry of the bonds joining the P and H atoms, and a given disposition of the bonds around the phosphorus atom, there is only a little influence of the nature of the substituents on the J{sub PH} spin coupling constants. The geometrical dependence of the {sup 3}J{sub PH} cannot be explained by a 'Karplus law'. There is an influence of the bond disposition around phosphorus. In the case of the {sup 2}J{sub P-C-H}, one can plot a curve {sup 2}J{sub P-C-H} = f({alpha}) (0{<=} {alpha} {<=} 180), {alpha} denote the dihedral angle of the two plane defined the first one by the P, C and H atoms, and the second one by the P-C bond together with the three-fold axis of the bond around phosphorus assuming a regular pyramidal arrangement. The function {sup 2}J{sub P-C-H} = f({alpha}) has two maxima, one for {alpha} = 0 degrees and the other for {alpha} = 180 degrees, and also a minimum for {alpha} = 110 degrees. (author) [French] Ce travail consiste en l'analyse par resonance magnetique nucleaire des constantes de couplage phosphore-proton dans des derives organo-phosphores tricoordines dans un double but: examen de la stabilite des liaisons au niveau du phosphore et etude de l'influence de la disposition des liaisons et de la nature de

  20. Contribution to the study of the textures of uranium rods prepared by sintering-extrusion, and their consequences on the thermal cycling behaviour; Contribution a l'etude des textures de barreaux d'uranium mis en forme par frittage-extrusion et leurs consequences sur le comportement au cyclage thermique

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-11-01

    {alpha} ou {beta} (a divers taux d'extrusion), a partir de poudre legerement oxydee, ont ete soumis a l'epreuve du cyclage thermique. Parallelement, les techniques de dilatometrie et de rayons X ont permis de determiner les textures engendrees dans ces materiaux lors de leur elaboration. Une relation est alors proposee entre texture et allongement par cyclage thermique. 1. Deux types de barreaux ont ete etudies: Frittes-extrudes en phase {beta}: faible densite (88 pour cent densite theorique), gros grains et absence de texture preferentielle; Frittes-extrudes en phase {alpha}: forte densite (96 pour cent densite theorique), grains fins et texture preferentielle prononcee. 2. Apres 1000 cycles thermiques entre 20 C et 550 C les allongements sont les suivants: 2 pour cent pour un uranium fritte-extrude en phase {beta} (avec fissuration de surface); entre 14 et 56 pour cent suivant le taux d'extrusion, pour un uranium fritte-extrude en phase {alpha} (sans alteration de surface). 3. Dans le cas des barreaux frittes-extrudes en phase {alpha} la determination des figures de poles, par la methode de Schulz en reflexion a fait apparaitre deux orientations preferentielles, paralleles a la direction de filage: l'une proche de [100], l'autre proche de [110]. La dilatometrie a ensuite permis de preciser quantitativement la proportion de chaque composante dans la texture d'ensemble, et de mettre en evidence l'augmentation du pourcentage de [100] lorsque le degre d'ecrouissage augmente. 4. Enfin le rapprochement de 2 et 3 montre que les allongements dus au cyclage thermique sont lies au pourcentage des composantes de texture. Il apparait que plus le pourcentage [100] augmente, plus l'allongement diminue. Par contre le comportement de materiaux a fort pourcentage de [110] reste imprecis. (auteur)

  1. Contribution to the study of french pitchblendes; Contribution a l'etude des pechblendes francaises

    Energy Technology Data Exchange (ETDEWEB)

    Geffroy, J. [Commissariat a l' Energie Atomique, Lab. de Mineralogie, Centre de Chatillon (France). Centre d' Etudes Nucleaires; Sarcia, J.A. [Commissariat a l' Energie Atomique, Div. de la Crouzille, Haute Vienne (France). Centre d' Etudes Nucleaires

    1955-07-01

    The authors first review the characteristics of uraninite-pitchblende, as deduced of present literature. They set apart from typical pitchblende a black oxide aspect, which probably corresponds to neo-formations, and a 'para-pitchblende' aspect, which they relate to deep sur-oxidation of normal pitchblende. They insist on the easy replacement of pitchblende by silica. and give indications as to changes in vein stones (fluorite, quartz, etc...). A detailed study of paragenesis and successions in french uranium districts follows (including discussion of uranium of uranium-bearing coals). The authors attempt to classify french pitchblende veins. They are chiefly epithermal and poor in satellite ores. Three types of deposits are identified: massive - pitchblende type, silica type, fluorite type. These deposits, as those of Portugal, are included in granite, Central-European peri-batholitic types where uranium associates which Ni, Co, Bi and Ag, are in France both rare and poor. Finally, the authors attempt to bring out in the european Hercynian area a particular distribution of paragenetic types. (authors) [French] Les auteurs recapitulent d'abord les caracteres et les occurences de l'uraninite - pechblende, tels qu'ils peuvent etre degages de l'actuelle bibliographie. Ils exposent ensuite les faits qui du point de vue mineralogique seulement ressortent de l'etude mineralogique et chalcographique des pechblendes francaises et de leurs satellites. Ils distinguent de la pechblende-type un facies oxyde noir; correspondant probablement a une neoformation, et un facies parapechblende, qui est rapporte a une sur oxydation hypogene de la pechblende proprement dite. Ils insistent sur le facile remaniement de la pechblende par la slice; et donnent quelques precisions sur les modifications des gangues (fluorine, quartz, etc...). Suit l'etude detaillee des parageneses et des successions dans les districts uraniferes francais: Divisions du

  2. Experimental studies of some of the physical features of beryllium-moderated intermediate reactors; Etude experimentale de quelques particularites physiques des reacteurs a neutrons intermediaires, ralentis au beryllium; Ehksperimental'ny e issledovaniya nekotorykh fizicheskikh osobennostej promezhutochnykh reaktorov s berillievym zamedlitelem; Estudios experimentales de algunas caracteristicas fisicas de los reactores intermedios moderados con berilio

    Energy Technology Data Exchange (ETDEWEB)

    Lejpunskij, A I; Kuznetsov, V A; Artyukhov, G Ya; Mogil' ner, A I; Prokhorov, Yu A; Steklovski, V M; Chernov, L A [Akademiya Nauk, Moskva, Union of Soviet Socialist Republics (Russian Federation)

    1962-03-15

    of neutrons absorbed by the uranium. The paper provides data, derived from the same assembly, on the efficiency of rods made of various absorbing materials. It gives the experimentally measured distribution of neutron density for neutrons of various energies in the neighbourhood of a boron-carbide rod, and the density of neutron captures by a 1/v detector within the rod. The paper also discusses methods used and the results obtained from experiments designed to assess the efficiency of recompensation, cylinders placed on the boundary between core and reflector. (author) [French] Le memoire analyse les resultats de plusieurs experiences effectuees sur l'ensemble critique PF-4, qui est destine a l'etude detaillee des particularites physiques des reacteurs a neutrons intermediaires. Les coeurs et les reflecteurs des differents esembles critiques etaient constitues par un assemblage compact de tubes en acier ou en aluminium dans lesquels etaient inseres des diques de diverses matieres. En combinant selon differentes proportions les disques d'uranium enrichi a 90% et les matieres de ralentissement et en introduisant dans le reflecteur des couches de ralentisseur de diverses epaisseurs, on a pu obtenir de grandes modifications du spectre des neutrons provoquant la fission. Le memoire decrit l'ensemble critique PF-4 et les differents assemblages qui le composent. Les auteurs analysent l'efficacite relative du ralentissement interieur et exterieur pour des reacteurs dans lesquels le rapport noyaux du ralentisseur noyaux d'uranium dans le coeur est tres peu eleve. Il ressort des experiences que, meme lorsqu'on emploie des reflecteurs tres epais, la faible dilution de l'uranium par le ralentisseur (le rap- port entre les noyaux du beryllium et de l'uranium-235 etant: {partial_derivative}Be/{partial_derivative}{sup 235}U{approx_equal}1) entraine un accroissement de la masse critique. Une partie importante du memoire est consacree a une analyse des effets hetero- genes produits

  3. Study of the {sup 14}C benzimidazole distribution in mice after inter-peritoneal injection; Etude de la repartition du benzimidazole {sup 14}C chez la souris apres injection intraperitoneale

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-07-01

    In order to provide further information on the mechanism of benzimidazole radioprotective activity, this work studies the tissual repartition in mice of this compound labelled with carbon 14. Experiments have showed that benzimidazole distribution is fast and homogeneous in all the tissues, but however affinity appears at the level of stomach and gastric content. Elimination is made through the urinary system and is very fast. (author) [French] Dans le cadre de l'etude du mecanisme de l'action radioprotectrice du benzimidazole, ce travail a pour objet l'etude de la repartition tissulaire chez la souris de ce compose marque au carbone 14. L'experimentation a montre que le benzimidazole se repartit tres rapidement et de facon pratiquement homogene dans tous les tissus, avec toutefois une affinite paraissant se manifester au niveau de l'estomac et du contenu gastrique. L'elimination, qui se fait par voie urinaire, est tres rapide. (auteur)

  4. Study of fission product {gamma} spectra in the band 2-500 keV; Etude du spectre {gamma} des produits de fission dans la bande 0-500 keV

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    In the study of the {gamma} spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [French] Dans l'etude du spectre {gamma} des produits de fission de l'uranium, on s'est plus particulierement interesse dans la presente note a determiner la partie du spectre qui s'etend entre 0 et 500 keV, au bout d'un fonctionnement donne de pile, et a suivre l'evolution de ce spectre dans le temps apres un arret de pile. L'etude peut porter sur les produits de fission apparus dans toute la pile ou sur ceux apparus dans un echantillon d'uranium suppose place en pile. C'est ce dernier cas que nous avons envisage. La determination du spectre s'appuie sur une partie theorique et sur une partie experimentale. Les fonctionnements de pile choisis sont differents dans les deux cas, ce qui permet d'etendre la gamme de validite des spectres traces ici. (auteur)

  5. Study of fission product {gamma} spectra in the band 2-500 keV; Etude du spectre {gamma} des produits de fission dans la bande 0-500 keV

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    In the study of the {gamma} spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [French] Dans l'etude du spectre {gamma} des produits de fission de l'uranium, on s'est plus particulierement interesse dans la presente note a determiner la partie du spectre qui s'etend entre 0 et 500 keV, au bout d'un fonctionnement donne de pile, et a suivre l'evolution de ce spectre dans le temps apres un arret de pile. L'etude peut porter sur les produits de fission apparus dans toute la pile ou sur ceux apparus dans un echantillon d'uranium suppose place en pile. C'est ce dernier cas que nous avons envisage. La determination du spectre s'appuie sur une partie theorique et sur une partie experimentale. Les fonctionnements de pile choisis sont differents dans les deux cas, ce qui permet d'etendre la gamme de validite des spectres traces ici. (auteur)

  6. Cécile ESTIVAL, Corps, imagerie médicale et relation soignant-soigné. Étude anthropologique au centre de cancérologie

    OpenAIRE

    Werner, Jean-François

    2011-01-01

    Cet ouvrage est directement issu d’une recherche doctorale, menée sous la direction de Sylvie Fainzang qui en a rédigé la préface. Comme l’indique le titre, il aborde l’imagerie médicale de manière oblique, en tant que médiation dans le rapport au corps (du patient à son propre corps, des soignants avec le corps du patient) et dans la relation soignant-soigné, soit deux champs de recherche amplement labourés par les anthropologues de la santé. Ce qui n’est pas le cas de l’imagerie médicale qu...

  7. L’équité au cœur des politiques climatiques : l’exemple des négociations relatives au climat et de la recherche de solutions à la crise énergétique

    Directory of Open Access Journals (Sweden)

    Loïc Aubrée

    2011-02-01

    Full Text Available L’article débat de la question de l’équité dans la lutte contre les changements climatiques. Il établit un parallèle entre le développement pris au niveau international de la négociation entre Etats d’une part, et la pauvreté au niveau d’une collectivité d’autre part. Dans les deux cas, il s’agit à la fois d’un principe moral essentiel, mais aussi d’une condition centrale des consensus et donc de la réussite des politiques face au défi climatique. La question de l’équité renvoie aussi très vite au changement nécessaire des modes de vie vers plus de sobriété.The article debates Equity Issues in the Climate Change debate is debated. A parallel is set between the development issues at the international level of negotiations between States, and poverty alleviation at the local community level. In both cases, the discussions stem from an essential moral principle, but also as a requisite for consensus and thus a condition of success of climate change policies to combat Climate Change. The issue of equity brings also forward the necessary modification of consumption patterns, into more frugal modes.

  8. Studies on solid-state physics carried out with the Saclay reactor (1962); Etudes de physique du solide realisees a la pile de Saclay (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-07-01

    This paper deals only with solid-state physics experiments carried out on outgoing beams: rather than giving a general review of the work performed, if refers to only a few of the most important studies or those nearest completion. These are being made with the experimental beams of the two Saclay reactors EL-2, with a central flux of 10{sup 13} n/cm{sup 2}, and - since 1958 - EL-3, whose central flux is equal ta 10{sup 14} n/cm{sup 2}. The experiments are being carried out by two separate groups of physicists, employing different techniques, namely neutron diffraction using a crystal spectrometer, and inelastic scattering using a time-of-flight spectrometer. (author) [French] Cet expose ne relate que des experiences de physique du solide faites sur des faisceaux sortis; plutot que de donner une revue de l'ensemble des travaux effectues, on ne cite que quelques etudes que l'on peut considerer comme plus essentielles ou mieux achevees. On utilise les faisceaux experimentaux des deux piles de Saclay, EL-2 dont le flux au centre est de 10{sup 13}n/cm{sup 2} et, depuis 1958, EL-3 pour laquelle il est egal a 10{sup 14} n/cm{sup 2}. Les experiences sont realisees par deux groupes de physiciens distincts, employant des techniques differentes, la diffraction des neutrons qui utilise un spectrometre a cristal, et la diffusion inelastique avec un spectrometre a temps de vol. (auteur)

  9. Etude théorique et expérimentale de l’effet d’inhibition de la corrosion d’un acier au carbone par les dérivées de base de Schiff en milieu acide chlorhydrique

    OpenAIRE

    Khenadeki, Amine

    2014-01-01

    Dans cette étude,l'effet de l'addition de certais composés organique de dérivées de basses de schiff sur la corrosion d'un acier au carbone en milieu acide chlorhydrique a été étudié à l'aide des méthodes électrochimiques(courbes de polarisation et spectroscopie d'impédance électrochimique) et gravimétriques.........

  10. Pierre Swiggers, Les Conceptions linguistiques des Encyclopédistes, Etude sur Ia constitution d'une théorie de Ia grammaire au siècle des Lumières, Sammlung Groos 21, Julius Groos Verlag-Heidelberg- Leuven University Press, Heidelberg 1984, 165 pp.

    Directory of Open Access Journals (Sweden)

    Pavao Tekavčić

    1986-12-01

    Full Text Available Le petit livre dont nous présentons ici lecompte rendu est I'oeuvre du jeune savant Pierre Swiggers, chercheur qualifié au Fonds national beige de la recherche scientifique, linguiste et philologue qui nous a donné dejà une serie d'études, sur le siècle des Lumières (L'Encyclopédie et la linguistique au XVI/le siècle, «Linguisti­ cae Investigationes» 311979; La grammaire dans /'Encyclopédie: Etat actuel des étu­ des, «Beiträge zur romanischen Philologie» 20/1981; La théorie syntaxique dans  /'Encyclopédie, «Lingua e stile» 18/1983 etc., sur l'historiographie linguistique (tout récemment: L'article en français: l'histoire d'un problème grammatical, «Re­ vue de Linguistique Romane» 49/1985, sur la linguistique du XVIIe et du XVIIIe siècle en général, etc. L'Auteur est done bien un spécialiste qualifié pour offrir au public linguistique une synthèse de ses recherches sur les théories grammaticales dans l'Encyclopédie.

  11. A study of the conformation and stability of nitroxide free radicals; Etude de la conformation et de la stabilite de radicaux libres nitroxydes

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-03-01

    les constantes de couplage des protons situes en {gamma} de l'azote ont une dependance spatiale tres marquee au meme titre que les protons situes en {beta}, ce que les etudes anterieures n'avaient pu preciser. Une analyse conformationnelle est effectuee par RMN a 310 MHz, en temperature variable. La synthese du di-t-butyl nitroxyde marque au carbone 13 en position {alpha} du groupement nitroxyde a permis de determiner avec certitude la constante d'interaction hyperfine electron carbone 13 quaternaire, grandeur qui n'avait pas ete mesuree jusqu'alors. Les constantes de couplage mesurees dans les radicaux piperidiniques tetramethyles en 2,2,6,6 ont pu etre ensuite attribuees a des carbones 13 situes en {beta} de l'azote, et leur variation a pu etre reliee a la conformation des cycles. C'est l'objet de la seconde partie. Dans un dernier chapitre, l'etude cinetique d'un radical nitroxyde instable, ayant un hydrogene en {beta}, met en evidence une decomposition bimoleculaire qui met en jeu la rupture de la liaison C-H; ceci est demontre par effet isotopique primaire. On peut conclure de cette etude qu'un nitroxyde est stable lorsque les differents groupes attaches a l'atome d'azote ne peuvent provoquer une decomposition du radical, soit intramoleculairement, si la geometrie de la molecule le permet, soit intermoleculairement par dimerisation sur un autre centre d'une molecule voisine, conduisant ainsi a une fragmentation ou a une disproportionation. (auteur)

  12. An economic study of the site of Marcoule; Etude economique du site de Marcoule

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    The study of this site of the Marcoule Center shows that its regional economical influence is limited to the buying power distributed among its personnel. This entails distortions between first this supplementary buying power and the overall markets within the possible Marcoule influence zone, and secondly the concentration on Bagnols-sur-Ceze and this town's normal extension possibilities. (author) [French] L'etude du site de Marcoule demontre que son influence economique se limite, pour la region, au pouvoir d'achat distribue a son personnel. Ceci entraine une disproportion d'une part entre ce pouvoir d'achat supplementaire et l'ensemble des marches contenus dans l'aire d'influence possible de Marcoule, d'autre part entre la concentration realisee a Bagnole-sur-Ceze et la capacite d'extension normale de cette agglomeration. (auteur)

  13. Production of heavy water in France; Etude sur la production d'eau lourde en France

    Energy Technology Data Exchange (ETDEWEB)

    Lerat, J M; Roth, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Lefrancois, B [Houllere du Bassin du Nord et du Pas de Calais (France)

    1964-07-01

    Since 1958, studies relating to heavy water production have covered several processes. Each one has been examined to a greater or lesser degree and attention has finally been concentrated on the isotopic exchanges between hydrogen sulphide and water and between ammonia and synthesis gas, the pilot experiment having shown that hydrogen distillation, although technologically satisfactory, was not competitive. NH{sub 3} synthesis gas exchange process; 1) Research was continued and led to the decision to build a production unit, devoted also to the synthesis of ammonia. The process essentially depends on the source of the synthesis gas; the use of a H{sub 2}O/H{sub 2} exchange, which could make it independent, has in fact been rejected for economic reasons. Amongst the various possible designs for the process, the one temperature system was chosen, in spite of certain technological problems, because of it provides: a high enrichment with a reduced number of contact devices. These have now been perfected after large-scale pilot tests. The original industrial experiment to be set in operation will supply useful information for second generation plants, whether they use the one temperature lay out again or whether they adopt the two temperature system. H{sub 2}S-H{sub 2}O exchange process. The pilot plant, described in 1958, has been used for a systematic study of corrosion. It was possible to proceed to preliminary specifications of plants, with 2 or 3 H{sub 2}S - H{sub 2}O stages exchange for primary enrichment. They final stage beyond a 10 to 20 p.100 D{sub 2}O concentration being carried out by the distillation of water. Various heat exchange systems have been studied in detail and it was concluded that choices, as for instance the one of optimum division of the cascade, were eventually to be made according to the particular economic conditions of creation at the chosen location of the plant. (author) [French] Depuis 1958 les etudes concernant la production d

  14. Singing as a Therapeutic Agent, inThe Etude, 1891-1949.

    Science.gov (United States)

    Hunter

    1999-01-01

    The Etude music magazine, founded by Theodore Presser, was one of a number of popular music magazines published in the years prior to the establishment of the music therapy profession in 1950. During its publication run from 1883 to 1957, over 100 music therapy related articles appeared, including 13 on the health benefits of singing published between 1891 and 1949. Written by authors with diverse backgrounds, such as the famous Battle Creek, Michigan physician John Harvey Kellogg and Boston music critic Louis C. Elson, the articles contained consistent and adamant support regarding the health benefits of singing. The advantages described were both physical and psychological, and were recommended prophylactically for well persons and therapeutically for ill persons. Although the articles varied in perspective, from philosophical to theoretical to pedagogical, there is a consistent holistic medicine theme that appeared almost ahead of its time and no doubt linked to the push for vocal music education in that era. The importance of The Etude in promulgating ideas that helped shape the early practice of music therapy should not be underestimated. For much of its publication run The Etude was the largest music periodical in print, reaching its peak circulation of 250,000 copies per month in 1924.

  15. Realisation and subsequent improvements of a progressive wave laser. Application to the study of HFA fluorescence; Realisation et mise au point d'un laser UV a onde progressive. Application a l'etude de la fluorescence de l'hexafluoroacetone

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Alain

    1976-05-26

    different pressures and several observation wavelengths. This work confirms Ware's results: the lifetime is independent, within the experimental errors, of the HFA pressure over the range from 20 to 400 torr and has a mean value of 87 ± 2 ns (compared to Ware's value of 84 ± 2 ns). The measurements have been completed at different observation wavelengths (band pass: Δλ 6 nm). We also have checked that the lifetime is the same over the entire emission band in this pressure range. At low pressures (≤ 10 torr), however, with a new experimental arrangement, it has been seen that the apparent fluorescence lifetime begins to decrease with pressure at certain observation wavelengths, ranging from 80 ns at 70 torr to 56 ns at 0,5 torr. Our results are in good agreement with the photochemical mechanism proposed by Ware. (author) [French] Waynant, Shipman, Hogdson et Schafer ont recemment montre qu'il etait possible, en excitant un gaz avec une decharge electrique transversale et progressive, d'obtenir des emissions laser dans l'UV et l'UV lointain de courte duree. Ce dispositif experimental est connu sous le nom de laser a onde progressive. Jusqu'a present avec ce type de laser, des emissions stimulees ont pu etre observees dans les gaz suivants: N{sub 2} (C{sup 3}πu → B{sup 3}πg), CO(A{sup 1}π → X{sup 1}Σ), H{sub 2}[B{sup 1}Σ → X{sup 1}Σ) et H{sub 2}(C{sup 1}π → X{sup 1}Σ) situees respectivement a 337, 193, 160 et 120 nm. La brievete des impulsions obtenues et les longueurs d'onde emises par ce type de laser nous ont incites a construire un tel laser et a etudier ses caracteristiques. Notre laser se compose principalement d'un canal de 24 cm, limite en largeur par deux electrodes en acier en forme de T entre lesquelles s'effectue la decharge. L'etude des caracteristiques de ce laser a azote donne les resultats suivants: une mesure a basse resolution de l'emission laser, due a la bande 0-0 du systeme 2{sup e} positif de l'azote situee a 337.1 nm, montre que l

  16. Etude relative à la lutte contre les atteintes au droit d’auteur sur internet: rapport pour le SPF économie, P.M.E., classes moyennes et énergie : rapport final

    OpenAIRE

    Dusollier, Séverine; Hallemans, Sandrine; Colin, Caroline

    2012-01-01

    Les atteintes aux droits d’auteur sur Internet peuvent prendre différentes formes, qu’il s’agisse des échanges illégaux d’oeuvres sur les réseaux peer-to-peer, du streaming illégal, de la diffusion d’oeuvres sur les réseaux sociaux ou tout autre site ou blog sans l’autorisation de leur auteur… Toutes ces pratiques sont très difficiles à enrayer et jusqu’alors, malgré les multiples pistes de réponse explorées par les titulaires de droits (poursuites des utilisateurs individuels à des fins diss...

  17. A comparative study of the {sup 90}Sr/Ca ratio in human diet and bone tissue; Etude comparee chez l'homme du rapport {sup 90}Sr/Ca dans l'alimentation et le tissu osseux

    Energy Technology Data Exchange (ETDEWEB)

    Coulon, R; Madelmont, C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    A comparative study of both the evolution of strontium-90 content in the bones of individuals of different ages for the period 1962-1967 as related to calcium, and the corresponding diets allowed to establish the relationship between food contribution and the resulting bone burden. The study is mainly devoted to the group of adults for which a mathematical expression is proposed which allows for the exchangeable form of a skeletal calcium fraction turned over in less than a year from the dietary calcium, and the stabilized form constituting the larger part of bone tissue characterized by a slow turnover. Both the amount of the exchangeable fraction and the turnover rate of the stabilized fraction are determined for vertebrae and ribs. At birth, bone levels indicate that the calcium used for skeleton modelling during foetal life originates from both maternal diet and bone tissue and a value is given, to their relative significance. There appears a good relationship between bone levels in infants from 6 months to 1 year of age and their diets. The physiological parameters particular to this age are quantified. (authors. [French] L'etude comparee de l'evolution de la teneur en strontium 90 rapportee au calcium, mesuree dans les os d'individus a differents ages durant la periode 1962-1967 et celle du regime alimentaire correspondant, a permis d'etablir la relation qui existe entre l'apport du a l'alimentation et la charge osseuse qui en resulte. L'essentiel de l'etude est consacre au cas des adultes. Pour ce groupe la formulation mathematique proposee tient compte de la presence de la forme echangeable d'une fraction du calcium osseux, renouvelee en moins d'un an a partir du calcium alimentaire, et de la forme stabilisee, constituant la majeure partie du tissu osseux, caracterisee par un renouvellement lent. L'importance de la fraction echangeable, ainsi que le taux de renouvellement de la fraction stabilisee sont etablis pour les vertebres et les cotes. La

  18. Contribution to the study of the uranium-hydrogen system; Contribution a l'etude du systeme uranium-hydrogene

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-01-01

    Previous work on uranium-hydrogen system is reviewed. The U-H{sub 2}-UH{sub n} equilibrium is then investigated at pressures below one atmosphere, i.e. at temperatures lower than 430 deg. C. The hydride obtained at equilibrium is deficient in hydrogen (UH{sub n<3}), the hydrogen deficit increasing as the temperature rises. Thermodynamic functions for the formation of non-stoichiometric hydride and of one hydrogen vacancy are derived from pressure composition isotherms, in U-H phase diagram is proposed. The hydrogenation of U-UC alloys is also examined at pressures below one atmosphere with regard to the equilibrium: (free U + UC) - H{sub 2}-UH{sub n}. The equilibrium conditions are found different from that observed for pure uranium. (author) [French] Une etude bibliographique du systeme uranium-hydrogene est exposee. L'equilibre U-H{sub 2}-UH{sub n} est ensuite etudie sous des pressions inferieures a une atmosphere, soit aux temperatures inferieures a environ 430 degs. C. L'hydrure obtenu a l'equilibre est deficitaire en hydrogene - UH{sub n<3} - et d'autant plus que la temperature s'eleve. Les grandeurs thermodynamiques relatives a la formation et a la saturation de l'hydrure, ainsi qu'a la formation d'une lacune d'hydrogene sont deduites des pressions d'equilibre. Un modele de diagramme de phases U-H est propose. L'hyduration des alliages U-UC est etudiee egalement sous des pressions inferieures a l'atmosphere, au point de vue de l'equilibre (U libre + UC) - H{sub 2}-UH{sub n}. Les conditions d'equilibre sont trouvees differentes de celles observees sur l'uranium pur. (auteur)

  19. Contribution to the study of can deformations in the fuel elements of gas-graphite reactors during thermal cycling; Contribution a l'etude des deformations des gaines des elements combustibles de reacteur graphite-gaz au cours du cyclage thermique

    Energy Technology Data Exchange (ETDEWEB)

    Gauthron, M; Boudouresques, B; Delpeyroux, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The cans of fuel cartridges used in reactors of the gas-graphite type have either longitudinal fins of variable thickness, short herring-bone fins, or else a mixture of the two. An important test of the strength of these cartridges is their behaviour during thermal cycling carried out in cells reproducing in-pile conditions. It has been observed during with rapid cooling that there occurs a shortening at the base of the fins which can be accompanied in particular by a compression effect at the fin type, which has a tendency to curl, and by a tractive force acting on the body of the can at the ends of the longitudinal fins; this last phenomenon can result in a fracturing of the welds at the extremities or of the ends of the cartridge. This report presents first of all the way in which the stress diagram can be drawn for a can touching the fuel, and then the effect of the ratchet along a fin fixed to a bar with or without grooves. Finally the importance is shown of the test cycling variables (temperature, heating and cooling rates). (authors) [French] Les gaines des cartouches combustibles des reacteurs de la filiere graphite-gaz comportent soit des ailettes longitudinales plus ou moins epaisses, soit de courtes ailettes a chevrons, soit un ensemble des deux. Un test important de la tenue des cartouches, est la tenue au cyclage thermique en cellule pour reproduire le comportement en pile. On a observe au cours des cyclages a refroidissement rapide, un raccourcissement a la base des ailettes qui peut s'accompagner notamment d'une mise en compression du sommet de l'ailette qui a tendance a friser, et d'une traction exercee sur le corps des gaines au bout des ailettes longitudinales; ce dernier phenomene peut se traduire par des ruptures de soudures d'extremites ou des parties terminales de la cartouche. Ce rapport presente d'abord la maniere dont peut etre trace le diagramme des contraintes dans une gaine liee au combustible, puis l'effet du rochet le long d

  20. Etude des mécanismes d'interaction, au cours du procédé d'emboutissage à chaud, entre les surces atmosphériques d'hydrogène et les aciers à haute résistance revêtus d'Al-Si

    OpenAIRE

    Mandy, Mélodie; Jacques, Pascal; Georges, Cédric; Journée Jeunes Chercheurs 2015 - Commission "Corrosion sous contrainte / Fatigue-Corrosion"

    2015-01-01

    Dans l’industrie automobile, le défi permanent d’allègement en vue de diminuer la consommation de carburant est profitable tant au niveau économique qu’écologique. Pour permettre cette diminution de masse sans compromettre pour autant la sécurité des passagers, il est donc essentiel de développer des nuances d’aciers toujours plus résistantes. Néanmoins, ces aciers doivent également garder une certaine ductilité nécessaire à leur mise en forme, mais aussi fondamentale pour la sécurité des pas...

  1. Some magnetic resonance properties of solutions of sodium in liquid ammonia; Contribution a l'etude des solutions de sodium dans l'ammoniac liquide par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-02-01

    Dilute solutions of sodium in liquid ammonia are studied by the mean of dynamic polarization techniques, and with the aid of Becker Lindquist and Alder model. Paramagnetic shifts are computed as a function of the 'average spin density', for each of the nuclear spin system. The nuclear contributions to the Overhauser shift are computed in the same way. A theoretical study of the main relaxation processes is carried out for each of the nuclear spin system and for the electronic spin system. The dynamic polarization experiments consist in classical measurement of the Overhauser enhancement for nitrogen, and in direct measurements of nitrogen Knight shift and nuclear contributions to the Overhauser shift by the mean of double irradiation techniques. The results show that, in dilute solutions, the relaxation of nitrogen arises from quadrupole interaction and from hyperfine interaction with unpaired electrons. Both interactions are of the same order of magnitude. Overhauser shift measurements show that the spin density is negative at the proton site, in agreement with Hughes results. (author) [French] Les solutions diluees de sodium dans l'ammoniac sont etudiees au moyen des techniques de la polarisation dynamique, sur la base du modele de Becker Lindquist et Aider. Les deplacements paramagnetiques des raies de resonance nucleaire des differents noyaux sont analyses en faisant appel a la notion de ''densite moyenne de spin'' introduite par l'auteur; et les differentes contributions nucleaires au deplacement d'Overhauser sont calculees en fonction de cette meme grandeur. Une etude theorique de la relaxation de chaque systeme de spin permet d'evaluer l'importance relative des differents mecanismes mis en jeu. Les experiences de polarisation dynamique effectuees au cours de ce travail consistent en mesures classiques de l'effet Overhauser sur l'azote, d'une part, et en la mise en oeuvre de techniques originales pour mesurer le deplacement de Knight de l'azote et les

  2. Theoretical study of properties due to the curvature in the toroid shape in magnetohydrodynamics; Etude theorique des proprietes dues a la courbure dans les configurations toriques en magnetohydrodynamique

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-03-01

    - We are considering a toroidal plasma centred around a closed {gamma}. When the rotational transform L/2{pi} approach an integer k if some specific relations are not satisfied curvature effects can become very important. When the rotational transform is created by current flowing in the plasma this happen if the coefficient a{sub k} of the Fourier expansion of curvature 1/R(s) of is non equal zero. One find then that the influence of a{sub k} is preponderant and that is possible to neglect all the other members of the series to study the neighbourhood of the corresponding equilibrium singularity. By developing an adapted coordinate system it is thus possible to take into account curvature effects at the lowest order. Equilibrium study bring us to introduce an equilibrium parameter {nu} {<=} 1 characterizing curvature effects. It is shown that the more {nu} is near of 1 the more shear and V{sup {phi}} quantities occurring in the stability criterion are important. Finally stability investigation show that the larger is the integer k the smaller is the domain of stability when L/2{pi} is near of k. (author) [French] Nous considerons un plasma toroidal centre autour d'une courbe fermee {gamma}. Lorsque la transformation rotationnelle L/2{pi} est voisine d'un nombre entier k, si certaines relations ne sont pas satisfaites, les effets de courbure peuvent devenir tres importants. Quand la transformation rotationnelle est cree par les courants circulant dans le plasma ceci se produit si le coefficient a{sub k} du developpement en serie de Fourier de la courbure 1/R(s) de {gamma} est non nul. On trouve alors que l'influence du k-ieme coefficient devient preponderante et il possible de negliger les autres termes pour etudier le voisinage de la singularite d'equilibre correspondante. En developpant un systeme de coordonnees adapte il est alors possible de tenir compte des le premier ordre des effets de courbure. L' etude de l'equilibre conduit a introduire un parametre d

  3. Strange particle correlations measured by the Star experiment in ultra-relativistic heavy ion collisions a RHIC; Etude des correlations de particules etranges mesurees par l'experience STAR dans les collisions d'ions lourds ultra-relativistes au RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Renault, G

    2004-09-01

    Non-identical correlation functions allow to study the space-time evolution of the source of particles formed in ultra-relativistic heavy ion collisions. The STAR experiment is dedicated to probe the formation of a new state of nuclear matter called Quark Gluon Plasma. The proton - lambda correlation function is supposed to be more sensitive to bigger source sizes than the proton - proton because of the absence of the final state Coulomb interaction. In this thesis, proton - lambda, anti-proton - anti-lambda, anti-proton - lambda and proton - anti-lambda correlation functions are studied in Au+Au collisions at {radical}S{sub NN} = 200 GeV using an analytical model. The proton - lambda and anti-proton - anti-lambda correlation functions exhibit the same behavior as in previous measurements. The anti-proton - lambda and proton - anti-lambda correlation functions, measured for the first time, show a very strong signal corresponding to the baryon - anti-baryon annihilation channel. Parameterizing the correlation functions has allowed to characterize final state interactions. (author)

  4. Apparatus for studying the diffusion of rare gases in stainless steel; Appareil pour etude de la diffusion des gaz rares dans l'acier inoxydable

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    This apparatus enables measurements to be carried out on the diffusion of gaseous fission products and of gases in general across thin metallic walls at high temperatures. This work was initially intended to solve the problems involved in systems for detecting the rupture of a fuel element can (D.R.G.) by the diffusion of fission products through the cans at high temperatures. The extension of the work to other fields is envisaged. (author) [French] Cet appareil permet d'effectuer des mesures sur la diffusion des produits de fission gazeux, et des gaz en general, au travers de parois metalliques minces a haute temperature. Au depart, ce procede devait contribuer a resoudre les problemes poses aux systemes detecteurs de rupture de gaine (D.R.G.), par la diffusion des produits de fission au travers des gaines de cartouches a haute temperature. Son extension a d'autres etudes est envisagee. (auteur)

  5. The synthesis and spectroscopic study of stable free radicals related to piperidine-n-oxyl, including a stable bi-radical; Syntheses et etudes spectroscopiques de radicaux libres piperidiniques et d'un biradical stable, du type nitroxyde

    Energy Technology Data Exchange (ETDEWEB)

    Briere, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires, Laboratoire de chimie organique physique

    1967-06-01

    A new synthesis of di-tert-butyl nitroxide using the reaction between tert-butyl magnesium chloride and nitro-tert-butane is presented in the first section. Synthesis and investigation of stable free piperidine-N-oxyl radicals are described in the second section. All these nitroxides have been characterised by their I. R., U. V. and E. P. R. absorption spectra. The final section contains a description of the synthesis of a stable bi-radical of the nitroxide type by condensation of 2,2, 6, 6-tetramethyl-piperid-4-one-l-oxyl with hydrazine. (author) [French] La premiere partie expose une nouvelle methode de synthase du di-t-butyl nitroxyde, par action d'halogenures de t-butyl magnesium sur le nitro-t-butane (Rdt maximum 45 pour cert, purete 86 pour cent). Une etude de radicaux. libres stables pipericliniques est faite dans une seconde partie. Ces composes sont obtenus par oxydation de derives de la triacetonamine. Les caracteristiques spectroscopiques ultra-violette, infra-rouge, et paramagnetique electronique de ces radicaux sont donnees. La grande inertie chimique du groupement nitroxyde a permis la syn-these d'un biradical stable par formation d'azine d'une cetone radicalaire, ce qui fait 1'objet de la troisieme partie. (auteur)

  6. PRATIQUES DE CONTROLE TOUT AU LONG DE LA RELATION DE FRANCHISE : UNE DOUBLE ENQUETE FRANCHISEUR-FRANCHISE

    OpenAIRE

    Goullet , Catherine

    2012-01-01

    International audience; This communication proposes a study of the control in the service franchising networks throughout the franchisors-franchisees relationship. From an interview-based exploratory research previously realized, a franchising network control model was proposed. An empirical research from the dyad franchisors - franchisees presents a descriptive analysis of the control system and tests on the evolution of these practices all to the life cycle of the relation. The results show...

  7. Preliminary Studies on Irradiation of Some Common Stored-Grain Insects in Pakistan; Etudes preliminaires sur l'irradiation de certaines especes communes d'insectes nuisibles aux cereales engrangees au Pakistan; Predvaritel'noe izuchenie rezul'tatov oblucheniya nekotorykh obychnykh ambarnykh nasekomykh v Pakistane; Estudios preliminares sobre los efectos de la irradiacion en algunas de las plagas insectiles de los silos mas comunes en el Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Heshamul [Department of Plant Protection, Ministry of Food and Agriculture, Karachi (Pakistan)

    1963-09-15

    The response of some major insect pests of stored grains to various radiation dosages from a Co{sup 60} source made available through the courtesy of the Pakistan Atomic Energy Commission has been studied. A dosage of 20 000 r produced 100% mortality of the adults of Rhizopertha dominica and Tribolium castaneum within a period of 11 d. A lower dose (10 000 r) was, however, effective in 23 d. The adults of Sitophilus granarius evinced comparatively high susceptibility and when they were exposed to 10 000 r, total mortality was attained in 7d. The larvae of Trogoderma granarium, however, proved to be the most resistant; they were not responsive to the lower dosages, and 100% control was attained only with 25 000 r in 26 d. The maximum dosage of 250 000 r gave an instant kill in all these cases, but apart from being too high it also adversely affected the viability of the grains. Since, however, their nutritive value remained unaffected, this treatment might be of use where immediate disinfestation of non-seeding edible grains was desired. Eggs of Bruchus quadmmaculatus failed to hatch when exposed to 2500 r. Studies on other stages and dosages are in progress. (author) [French] On a etudie la reponse a differentes doses de rayonnements de quelques especes d'insectes particulierement nuisibles aux cereales engrangees; on a utilise a cet effet une source au {sup 60}Co fournie par la Commission pakistanaise de l'energie atomique. Une dose de 20 000 r a provoque en l'espace de 11 j une mortalite de 100% chez les adultes de la Rhizopertha dominica et du Tribolium castaneum. Une dose de 10 000 r a donne le meme resultat en 23 j. Les adultes du Sitophilus granarius ont montre une sensibilite beaucoup plus elevee: une dose de 10 000 r a entraine une mortalite de 100% en 7 j. Ce sont les larves de la Trogoderma granarium qui se sont revelees les plus resistantes; elles ont ete insensibles aux doses de faible intensite et la mortalite de 100% n'a ete obtenue qu'avec 25 000 r

  8. Preparation of C{sup 14}-labelled tetrazolium salts and tracer study of the tetrazene-formazan rearrangement; Preparation de sels de tetrazolium marques au carbone-14 et etude de la transposition tetrazene-formazan, au moyen d'indicateurs radioactifs; Izgotovlenie mechennykh C{sup 14} solej tetrazosoedinenij i issledovanie pri pomoshchi indikatorov peregruppirovok tetrazona-formazana; Preparacion de sales de tetrazolio marcadas con {sup 14}C y estudio de la transposicion tetraceno-formazan con ayuda de trazadores

    Energy Technology Data Exchange (ETDEWEB)

    Marton, Joseph; Meisel, Julia [Central Research Institute for Chemistry of the Hungarian Academy of Sciences, Budapest (Hungary); Gosztonyi, Thomas [Institute of Organic Chemical Technology, Technical University, Budapest (Hungary)

    1962-03-15

    The preparation of [5-C{sup 14}]-TTC, [5, 5'-di-C{sup 14}]NT (neotetrazolium) and [5, 5'-di-C{sup 14}]-BT (tetrazolium blue) starting from benzaldehyde- [1-C{sup 14}] has been accomplished. The yields for both mono- and ditetrazolium salts are high, and the products can be obtained with high sp. activity. The purity of the samples was investigated by paper chromatography. In the case of ditetrazolium salts some impurities could be detected and conclusions drawn as to their structure and quantity. A method has been developed to prepare C{sup 14}- labelled ditetrazolium salts of high purity. The formation of the formazan, the precursor of the tetrazolium salt, goes through an unstable intermediate of tetrazene-type structure which rearranges rapidly in basic medium, to yield the formazan. The tetrazene intermediate can be isolated under suitable conditions. By using C{sup 14}-labelled benzaldehyde phenylhydrazone this rearrangement was investigated and a verification of its intramolecular character given. (author) [French] On a procede a la preparation de [5-C{sup 14}]-TTC, de [5,5'-di-C{sup 14}] NT (neotetrazolium) et de [5,5'-di-C{sup 14}]-VT (bleu de tetrazolium), en partant du benzaldehyde-[1-C{sup 14}]. On a pu obtenir un grand rendement, tant pour les sels de monotetrazolium que pour les sels de ditetrazolium, et des produits d'une activite specifique elevee. La purete des echantillons a ete examinee par chromatographie sur papier. Dans le cas des sels de ditetrazolium, on a pu deceler quelques impuretes et tirer des conclusions quant a leur structure et quantite. On a mis au point une methode permettant de preparer des sels de ditetrazolium marques au carbone-14 et presentant une grande purete. Dans la synthese du formazan, precurseur du sel de tetrazolium, on obtient un produit intermediaire instable d'une structure analogue a celle du tetrazene; ce produit se transforme rapidement en milieu alcalin pour donner du formazan. Le tetrazene intermediaire peut

  9. Instrumental performance of an etude after three methods of practice.

    Science.gov (United States)

    Vanden Ark, S

    1997-12-01

    For 80 fifth-grade students three practice conditions (mental, mental with physical simulation, and physical with singing) produced significant mean differences in instrumental performance of an etude. No significant differences were found for traditional, physical practice.

  10. Use of a Monte-Carlo method for studying the statistical distribution of electric fields around an ion in a one-component plasma; Etude, par une methode de Monte-Carlo de la repartition statistique des champs electriques au niveau d'un ion, dans un plasma a une composante

    Energy Technology Data Exchange (ETDEWEB)

    Rossignol-Guzzi, D [Commissariat a l' Energie Atomique, 94 - Limeil-Brevannes (France). Centre d' Etudes Nucleaires

    1968-11-01

    A Monte-Carlo simulation has been made of the equilibrium configurations taken by a plasma of equally charged punctual ions, immersed in a uniform neutralizing background of electrons. The statistical repartition of the electric field acting on one ion, needed to obtain Stark effect, was specially obtained. Comparison for dense plasmas, was made with the former works of Holtzmark, Mayer, Broyles. (author) [French] On simule sur ordinateur, suivant une methode de Monte-Carlo, les configurations prises a l'equilibre thermodynamique par un plasma d'ions ponctuels et de meme charge, places dans un milieu d'electrons uniformement distribues. On etudie, en particulier, la repartition statistique des champs electriques au niveau d'un ion, utilisee dans les calculs d'effets Stark. On compare, dans le cadre des plasmas denses, les resultats obtenus aux travaux precedents de Holtzmark, Mayer, Broyles. (auteur)

  11. Generalized study of the return to equilibrium of a particle in a plasma (Fokker-Planck formalism) (1961); Etude generale du retour a l'equilibre d'une particule au sein d'un plasma (formalisme de Fokker-Planck) (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Faculte des Sciences de Caen, 14 (France)

    1961-07-01

    The author examines the problem of the return to equilibrium of a particle in a plasma and completely explains Fokker-Planck equation. After that, he studies the possibility of interpreting the return of the test particle to Maxwellian distribution, using the development - which is obtained. He discusses the validity limits of the Rosenbluth, MacDonald and Judd approximation. (author) [French] Examinant le probleme du retour a l'equilibre d'une particule test au sein d'un plasma en equilibre, l'auteur cherche a expliciter completement l'expression de l'operateur de Fokker-Planck. Il etudie ensuite les conditions de coherence, c'est-a-dire la possibilite pour le developpement obtenu de traduire le retour de la particule test a l'etat maxwellien et discute des limites de validite de la formule de 'Rosenbluth, Mac Donald et Judd'. (auteur)

  12. Study of the diffusion in the {alpha} brasses, using the evaporation or condensation of zinc - influence of the diffusion sense and of impurities (first and second thesis); Etude de la diffusion dans les laitons {alpha} au moyen des methodes d'evaporation ou de condensation du zinc influence du sens de diffusion et de la presence d'impurete (premiere et deuxieme these)

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-12-15

    The author develops a zero concentration extrapolation method for the exact determination of the diffusion coefficient. He applies it to the comparison of the inward and outward diffusion coefficient in {alpha} brasses. In a second part he shows the large influence of traces of some elements such as P, As, Sb, on the diffusion velocity in {alpha} brasses. (author) [French] L'auteur montre comment, au moyen d'une extrapolation a variation de concentration nulle, ces methodes permettent d'atteindre rigoureusement la valeur du coefficient de diffusion. Il les utilise pour comparer la valeur du coefficient de diffusion avec enrichissement en zinc a la valeur du coefficient de diffusion avec appauvrissement en zinc. Dans une seconde partie, il met en evidence la grande influence de traces d'elements tels que le phosphore, l'arsenic, l'antimoine sur la vitesse de diffusion dans les laitons {alpha}. (auteur)

  13. Study of the properties of an electron linac beam by means of the electromagnetic fields associated with the beam; Etude des proprietes du faisceau d'electrons d'un accelerateur lineaire au moyen des champs electromagnetiques associes a ce faisceau

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-07-01

    For measuring the diverse characteristic parameters of a Linac electron beam, the one method causing the least perturbation to the electron beam itself, consists in the detection of signals induced in certain types of detectors by the electromagnets fields associated with the beam. Some particular detectors are then described, for measuring the following characteristic parameters of a Linac electron beam; a) electron beam peak current, a) longitudinal dimension and density of an elementary electron bunch, c) phase position of the electrons on the travelling sine wave of the accelerating field, d) transverse position of the beam. These particular electrodes are then used to provide experimental data In order to check the theoretical computations giving the longitudinal and transversal motions Of the electrons during their acceleration. (author) [French] Parmi les methodes de mesure des diverses caracteristiques du faisceau d'electrons d'un accelerateur lineaire, celles qui perturbent le moins le faisceau sont les methodes dans lesquelles l'energie du signal de mesure provient de la perturbation par l'electrode de mesure des champs electromagnetiques associes au faisceau. On decrit les electrodes de ce type qui ont ete mises au point pour mesurer les caracteristiques suivantes du faisceau d'electrons: a) courant crete, b) extension en phase d'un paquet elementaire d'electrons, c) phase d'accrochage des electrons, d) position transversale moyenne des electrons. On decrit ensuite comment les signaux provenant de ces diverses electrodes peuvent etre utilises pour verifier experimentalement les previsions theoriques des mouvements longitudinaux et transversaux des electrons en cours d'acceleration. (auteur)

  14. Study of the properties of an electron linac beam by means of the electromagnetic fields associated with the beam; Etude des proprietes du faisceau d'electrons d'un accelerateur lineaire au moyen des champs electromagnetiques associes a ce faisceau

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-07-01

    For measuring the diverse characteristic parameters of a Linac electron beam, the one method causing the least perturbation to the electron beam itself, consists in the detection of signals induced in certain types of detectors by the electromagnets fields associated with the beam. Some particular detectors are then described, for measuring the following characteristic parameters of a Linac electron beam; a) electron beam peak current, a) longitudinal dimension and density of an elementary electron bunch, c) phase position of the electrons on the travelling sine wave of the accelerating field, d) transverse position of the beam. These particular electrodes are then used to provide experimental data In order to check the theoretical computations giving the longitudinal and transversal motions Of the electrons during their acceleration. (author) [French] Parmi les methodes de mesure des diverses caracteristiques du faisceau d'electrons d'un accelerateur lineaire, celles qui perturbent le moins le faisceau sont les methodes dans lesquelles l'energie du signal de mesure provient de la perturbation par l'electrode de mesure des champs electromagnetiques associes au faisceau. On decrit les electrodes de ce type qui ont ete mises au point pour mesurer les caracteristiques suivantes du faisceau d'electrons: a) courant crete, b) extension en phase d'un paquet elementaire d'electrons, c) phase d'accrochage des electrons, d) position transversale moyenne des electrons. On decrit ensuite comment les signaux provenant de ces diverses electrodes peuvent etre utilises pour verifier experimentalement les previsions theoriques des mouvements longitudinaux et transversaux des electrons en cours d'acceleration. (auteur)

  15. A Relativity Enhanced, Medium-Strong Au(I)···H-N Hydrogen Bond in a Protonated Phenylpyridine-Gold(I) Thiolate.

    Science.gov (United States)

    Berger, Raphael J F; Schoiber, Jürgen; Monkowius, Uwe

    2017-01-17

    Gold is an electron-rich metal with a high electronegativity comparable to that of sulfur. Hence, hydrogen bonds of the Au(I)···H-E (E = electronegative element) type should be possible, but their existence is still under debate. Experimental results are scarce and often contradictory. As guidance for possible preparative work, we have theoretically investigated (ppyH)Au(SPh) (ppy = 2-phenylpyridine) bearing two monoanionic ligands which are not strongly electronegative at the same time to further increase the charge density on the gold(I) atom. The protonated pyridine nitrogen atom in ppy is geometrically ideally suited to place a proton in close proximity to the gold atom in a favorable geometry for a classical hydrogen bond arrangement. Indeed, the results of the calculations indicate that the hydrogen bonded conformation of (ppyH)Au(SPh) represents a minimum geometry with bond metrics in the expected range for medium-strong hydrogen bonds [r(N-H) = 1.043 Å, r(H···Au) = 2.060 Å, a(N-H···Au) = 141.4°]. The energy difference between the conformer containing the H···Au bond and another conformer without a hydrogen bond amounts to 7.8 kcal mol -1 , which might serve as an estimate of the hydrogen bond strength. Spectroscopic properties were calculated, yielding further characteristics of such hydrogen bonded gold species.

  16. Physics related to control and safety of hybrid systems; Physique associee au controle et a la surete des systemes hybrides

    Energy Technology Data Exchange (ETDEWEB)

    Gueton, O

    2001-12-01

    Regarding nuclear waste management, ADS can be considered as large minor actinides burners. In a first part, a critical analysis of different reactor types shows that fast spectrum, helium coolant and nitride fuel, containing 100% minor actinides, agree perfectly with the high transmutation requirements of ADS. The control and safety demonstration of this system represents the main purpose of this study. Understanding spatial and dynamic behaviour of ADS flux is absolutely necessary. For this purpose, we have defined an indicator to quantify spatial decoupling. It shows, on the one hand, point kinetic deficiency to study local transients, and on the other hand, perturbations propagation differences between ADS and critical cores. Then, in a more concrete approach, accidental sequences (source transient, beam de-focalization, reactivity insertions, loss of flow, depressurization) are evaluated for this core, strongly loaded with minor actinides. It is shown that the automatic beam shutdown leads to preserve large safety margins for all studied transients. The accelerator emergency stop is induced by an unexpected evolution of the core control parameters. These parameters, except reactivity, can be directly measured in subcritical systems like in critical ones. Concerning reactivity, we suggest a new method for its absolute determination in ADS: at the time of reactor start-up, the reactivity must be calibrated by coupling two methods of relative reactivity measurements (pulsed source and Approached Source Multiplication) for successive subcritical levels. After that, the on-line follow-up of reactivity is obtained from this calibration like in a critical core. (authors)

  17. Relative approach to nano-film topography and magnetic characteristics: a study of their interdependence in a Ni/Au system

    International Nuclear Information System (INIS)

    Ebothé, Jean

    2014-01-01

    The present study investigates the influence of surface features on the magnetic properties of thin films by taking into account the role of the surface roughness (σ) /film thickness (d) ratio. Examination of the ratio from microscopic down to mesoscopic d values is then undertaken in connection with the evolution of the films' magnetic properties (p). The double dependence of p on d and σ expected from a real nano-film, emerged into a new relative approach to film characteristics, associated with the described (σ/d) ratio. A direct and consistent link between surface roughness and magnetic properties is established with no film surface treatment. This results in a revisited analytical treatment adapted for the study of nano-structured and mesoscopic-scale films. Application to the topography and magnetic properties of nano-crystallized Ni electrodeposits 60 < d < 1200 nm thick and grown on Au substrate, led to the identification of their Bloch-type acting magnetic structures. (papers)

  18. A study of the aptitude of soils under natural conditions to retain radiostrontium; Etude de la vocation des sols en place a la retention du radiostrontium

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    Independently of the theoretical study of the propagation of radioactivity in the soil as a result of submersions or of radioactive rain, the authors have studied directly and practically how this radioactivity can vary in the actual soil. To this end a simple, rapid method has been perfected; it makes it possible to maintain for each soil sample the natural parameters (structure, humidity, etc.) without introducing boundary effects. In the laboratory, after charging the soil samples, part of the study of the propagation of radioactivity is done by autoradiography; finally, as a practical application, the study of an atomic site illustrates the methods described. (author) [French] Independamment de l'etude theorique de la propagation de la radioactivite dans le sol a la suite de submersions ou de pluies radioactives, les auteurs ont etudie directement et pratiquement comment pourrait evoluer cette radioactivite dans les sols en place. Pour cela, une methode simple et rapide a ete mise au point; elle permet de conserver pour chaque echantillon de sol, les parametres naturels (structure, humidite, etc...), sans introduire d'effets de paroi. En laboratoire, apres mise en charge des massifs preleves, une partie de l'etude de la propagation des radioelements est realisee par autoradiographie; enfin, une application pratique, l'etude d'un site atomique, illustre l'expose. (auteur)

  19. A study of the aptitude of soils under natural conditions to retain radiostrontium; Etude de la vocation des sols en place a la retention du radiostrontium

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    Independently of the theoretical study of the propagation of radioactivity in the soil as a result of submersions or of radioactive rain, the authors have studied directly and practically how this radioactivity can vary in the actual soil. To this end a simple, rapid method has been perfected; it makes it possible to maintain for each soil sample the natural parameters (structure, humidity, etc.) without introducing boundary effects. In the laboratory, after charging the soil samples, part of the study of the propagation of radioactivity is done by autoradiography; finally, as a practical application, the study of an atomic site illustrates the methods described. (author) [French] Independamment de l'etude theorique de la propagation de la radioactivite dans le sol a la suite de submersions ou de pluies radioactives, les auteurs ont etudie directement et pratiquement comment pourrait evoluer cette radioactivite dans les sols en place. Pour cela, une methode simple et rapide a ete mise au point; elle permet de conserver pour chaque echantillon de sol, les parametres naturels (structure, humidite, etc...), sans introduire d'effets de paroi. En laboratoire, apres mise en charge des massifs preleves, une partie de l'etude de la propagation des radioelements est realisee par autoradiographie; enfin, une application pratique, l'etude d'un site atomique, illustre l'expose. (auteur)

  20. Studies of magnetism with inelastic scattering of cold neutrons; Etudes de magnetisme realisees a l'aide de la diffusion inelastique de neutrons froids

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    Inelastic scattering of cold neutrons can be used to study some aspects of magnetism: spins waves, exchange integrals, vicinity of Curie point. After description of the experimental set-up, several experiments, in the fields mentioned above, are analysed. (author) [French] La technique de diffusion inelastique des neutrons froids est utilisee pour etudier certains aspects du magnetisme: ondes de spins, integrales d'echange, etude au voisinage du point de Curie, etc. Apres une description de l'appareillage, on analyse diverses experiences effectuees dans les domaines enumeres plus haut. (auteur)

  1. Semiconducting La{sub 2}AuP{sub 3}, the metallic conductor Ce{sub 2}AuP{sub 3}, and other rare-earth gold phosphides Ln{sub 2}AuP{sub 3} with two closely related crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Eschen, M.; Kotzyba, G.; Kuennen, B.; Jeitschko, W. [Anorganisch-Chemisches Inst. der Westfaelischen Wilhelms-Univ., Muenster (Germany)

    2001-07-01

    The compounds Ln{sub 2}AuP{sub 3} were synthesized by reaction of the elemental components in evacuated silica tubes. Their crystal structures were determined from single-crystal diffractometer data. The compounds with Ln = La, Ce, and Pr crystallize with an orthorhombic U{sub 2}NiC{sub 3} type structure (Pnma, Z = 4). The structure refinement for Ce{sub 2}AuP{sub 3} resulted in a = 774.14(6) pm, b = 421.11(4) pm, c = 1612.3(1) pm, R = 0.019 for 1410 structure factors and 38 variable parameters. For Pr{sub 2}AuP{sub 3} a residual of R = 0.024 was obtained. Nd{sub 2}AuP{sub 3} crystallizes with a monoclinic distortion of this structure: P2{sub 1}/c, Z = 4, a = 416.14(4) pm, b = 768.87(6) pm, c = 1647.1(2) pm, {beta} = 104.06(1) , R = 0.022 for 1361 F values and 56 variables. The near-neighbor coordinations of the two structures are nearly the same. In both structures the gold and phosphorus atoms form two-dimensionally infinite nets, where the gold atoms are tetrahedrally coordinated by phosphorus atoms with Au-P distances varying between 245.8 and 284.2 pm. Two thirds of the phosphorus atoms form pairs with single-bond distances varying between 217.7 and 218.9 pm. Thus, using oxidation numbers the structures can be rationalized with the formulas (Ln{sup +3}){sub 2}[AuP{sub 3}]{sup -6} and (Ln{sup +3}){sub 2}Au{sup +1}(P{sub 2}){sup -4}P{sup -3}. Accordingly, La{sub 2}AuP{sub 3} is a diamagnetic semiconductor. Pr{sub 2}AuP{sub 3} is semi-conducting with an antiferromagnetic ground state, showing metamagnetism with a critical field of B{sub c} = 0.5({+-}0.1) T. In contrast, the cerium compound is a metallic conductor, even though its cell volume indicates that the cerium atoms are essentially trivalent, as is also suggested by the ferro- or ferrimagnetic behavior of the compound. (orig.)

  2. M. G.-F. Leclerc, Préfet de la Haute-Savoie lors de sa visite dans le tunnel du LHC au Point 2 avec D. Delikaris, Département Technologie; dans la caverne de l'expérience ALICE avec B. Erazmus, Collaboration ALICE et lors de la signature du livre d'or avec F. Bordry, Chef du Département Technologie. P. Fassnacht, Conseiller au Bureau des Relations internationales présent.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    M. G.-F. Leclerc, Préfet de la Haute-Savoie lors de sa visite dans le tunnel du LHC au Point 2 avec D. Delikaris, Département Technologie; dans la caverne de l'expérience ALICE avec B. Erazmus, Collaboration ALICE et lors de la signature du livre d'or avec F. Bordry, Chef du Département Technologie. P. Fassnacht, Conseiller au Bureau des Relations internationales présent.

  3. Studies on the Relationship of Organ Size and Scanning Picture; Etudes sur la Relation entre les Dimensions de l'Organe et le Scintigramme; Izuchenie sootvetstviya razmera organa i izobrazheniya ego na skennogramme; Estudios sobre la Relacion entre las Dimensiones de un Organo y el Centelleograma

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, R.; Fischer, J. [Institute for Clinical Radiology and I. Medical Clinic and Policlinic, University of Mainz, Federal Republic of Germany (Germany)

    1964-10-15

    maximal pulse rate as far as possible when comparing sizes. By retaining the same fixed relationships between channel width of the spectrometer, cut-off, pulse rate and scanning speed, a faithful depiction is obtained for large organs such as the spleen. (author) [French] On n'a etudie jusqu'a present la relation quantitative entre la surface du scintigramme et la coupe de l'organe examine qu'a l'occasion de determinations du volume de la thyroiede. Dans des mesures de ce genre, la precision de la description depend a de nombreux egards du materiel utilise: collimateur, ecran contre le bruit de fond, vitesse d'exploration, etc. Pour determiner les dimensions du foie, Yagan et d'autres ont introduit une methode utilisant un ecran variable. Pour des organes tels que la thyroiede et les reins, il y a interet a etablir une correlation nette entre l'image formee par les rayons X ou les donnees de la palpation et le tissu qui fixe ou ne fixe pas le radioisotope. Il importe de connaitre de facon precise les rapports de dimensions, par exemple, dans la scintigraphie des reservoirs de sang cardio-vasculaire. Dans le cas d'un organe comme la rate, dont les dimensions peuvent changer rapidement dans diverses maladies, l'exactitude du scintigramme a une importance decisive. Pour cette raison, on a procede a une serie d'etudes sur des fantomes pour determiner l'exactitude du scintigramme dans diverses conditions. Les fantomes utilises etaient en matiere plastique et pouvaient contenir des solutions radioactives. Les experiences ont ete faites dans l'air et dans l'eau; on a etudie les effets des variations de la concentration des radioisotopes, ainsi que les effets de divers parametres: distance du collimateur au sujet, ecran, renforcement du contraste, vitesse d'exploration, largeur du canal du spectrometre et epaisseur de la masse d'eau absorbante au-dessus de l'organe. On a utilise un 'Magnascanner' de la societe Picker, avec deux collimateurs differents: un collimateur alveolaire a

  4. Contribution to the study of diffusion in poly-phase system; Contribution a l'etude de la diffusion en systeme polyphase

    Energy Technology Data Exchange (ETDEWEB)

    Adda, Y; Philibert, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)

    1959-07-01

    this latter result and of the anomalies in the coefficient of diffusion should probably take into account the accumulation of reticular defects which would appear after displacement of the phase boundaries. (author) [French] Apres diffusion chimique entre deux metaux, a des temperatures auxquelles le diagramme d'equilibre indique l'existence de plusieurs phases, on observe, sur une section perpendiculaire au front de diffusion, des bandes paralleles correspondant a ces diverses phases. On sait que, dans ce cas, la courbe concentration-penetration presente alors une discontinuite a chaque interface. Les concentrations a l'aplomb de ces discontinuites donnent les limites de solubilites respectives des phases en presence. Au cours de nos essais relatifs au couple uranium-zirconium, nous avons verifie que ces concentrations ne varient pas avec la duree de diffusion et que, donc, les conditions de l'equilibre thermodynamique sont bien remplies. On dispose alors d'une methode interessante pour etablir le diagramme d'equilibre a l'etat solide, methode que nous avons appliquee au systeme U-Zr. Les etudes cinetiques de la diffusion polyphasee sont encore assez rares, par suite des difficultes experimentales. Aussi diverses methodes sont-elles proposees pour evaluer le coefficient de diffusion a partir d'etudes purement micrographiques (mesure des epaisseurs des phases intermediaires). Nos resultats experimentaux montrent que les hypotheses sur lesquelles sont basees ces methodes sont tres rarement valables. En effet, nous avons etabli les courbes concentration-penetration dans les systemes U-Zr (entre 590 deg. C et 950 deg. C), et U-MO (entre 800 deg. C et 1050 deg. C). Celles-ci montrent souvent des courbures tres accentuees, qui traduisent des variations du coefficient de diffusion qui ne peuvent pas s'exprimer suivant des relations simples. Enfin, nous avons observe certaines anomalies au voisinage des interfaces entre phases adjacentes. En outre, nous avons etudie l

  5. Contribution to the study of diffusion in poly-phase system; Contribution a l'etude de la diffusion en systeme polyphase

    Energy Technology Data Exchange (ETDEWEB)

    Adda, Y.; Philibert, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)

    1959-07-01

    this latter result and of the anomalies in the coefficient of diffusion should probably take into account the accumulation of reticular defects which would appear after displacement of the phase boundaries. (author) [French] Apres diffusion chimique entre deux metaux, a des temperatures auxquelles le diagramme d'equilibre indique l'existence de plusieurs phases, on observe, sur une section perpendiculaire au front de diffusion, des bandes paralleles correspondant a ces diverses phases. On sait que, dans ce cas, la courbe concentration-penetration presente alors une discontinuite a chaque interface. Les concentrations a l'aplomb de ces discontinuites donnent les limites de solubilites respectives des phases en presence. Au cours de nos essais relatifs au couple uranium-zirconium, nous avons verifie que ces concentrations ne varient pas avec la duree de diffusion et que, donc, les conditions de l'equilibre thermodynamique sont bien remplies. On dispose alors d'une methode interessante pour etablir le diagramme d'equilibre a l'etat solide, methode que nous avons appliquee au systeme U-Zr. Les etudes cinetiques de la diffusion polyphasee sont encore assez rares, par suite des difficultes experimentales. Aussi diverses methodes sont-elles proposees pour evaluer le coefficient de diffusion a partir d'etudes purement micrographiques (mesure des epaisseurs des phases intermediaires). Nos resultats experimentaux montrent que les hypotheses sur lesquelles sont basees ces methodes sont tres rarement valables. En effet, nous avons etabli les courbes concentration-penetration dans les systemes U-Zr (entre 590 deg. C et 950 deg. C), et U-MO (entre 800 deg. C et 1050 deg. C). Celles-ci montrent souvent des courbures tres accentuees, qui traduisent des variations du coefficient de diffusion qui ne peuvent pas s'exprimer suivant des relations simples. Enfin, nous avons observe certaines anomalies au voisinage des interfaces entre phases

  6. Use of 14 MeV neutrons in activation analysis. Experiments carried out at the Grenoble nuclear research Centre (1963); Utilisation de neutrons de 14 MeV en analyse par activation. Experience realisee au Centre d'etudes nucleaires de Grenoble (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Auboin, G; Guazzoni, P; Laverlochere, J [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1963-07-01

    The use of 14 MeV neutron irradiation makes it possible to extend the field of application of activation analysis to elements which cannot be activated in nuclear reactors (oxygen, boron, for example) or else to consider the possibility of 'portable' measurement units for routine analyses. With this aim, tests have been carried out for studying the sensitivity and interferences in the case of the dosing of oxygen in eleven different matrices using 150 and 300 kV SAMES accelerators producing 14 MeV neutrons by the reaction {sup 3}H (d, n) {sup 4}He. The sensitivity of the dosage methods for six writer elements has also been studied. The results obtained show that, for a neutron flux of 10{sup 10} n/4{pi}, the sensitivities vary from 100 {mu}g and 1 mg for oxygen in nine matrices (Be, Ta, Nb, Ti, Zr, Fe, Al, Sb, Si) and that it is possible to dose the six elements F, B, Y, Si, N, Al with sensitivities of between 1 an 1000 micrograms. (authors) [French] L'irradiation au moyen de neutrons de 14 MeV permet d'etendre le domaine d'application de l'analyse par activation a des elements non activables en reacteur nucleaire (oxygene, bore, par exemple) ou encore d'envisager des unites de dosage ''portables'' pour des analyses de routine. Dans ce but, des essais ont ete effectues pour etudier les sensibilites et les interferences dans le cas du dosage de l'oxygene dans onze matrices differentes, au moyen d'accelerateurs SAMES 150 et 300 kV. produisant les neutrons de 14 MeV par la reaction {sup 3}H (d, n) {sup 4}He. Des sensibilites de dosage ont egalement ete etudiees pour six autres elements. Les resultats obtenus montrent que, pour un flux de neutrons de 10{sup 10} n /4{pi}, les sensibilites varient entre 100 {mu}g et 1 mg, pour l'oxygene dans neuf matrices (Be, Ta, Nb, Ti, Zr, Fe, Al, Sb, Si) et qu'il est possible de doser les six elements F, B, Y, Si, N, Al avec des sensibilites se situant entre 1 et 1000 microgrammes. (auteurs)

  7. Study of reactions of metals with sulphur and phosphorus compounds by pulsed temperatures; Etude des reactions entre metaux et composes du soufre et du phosphore au moyen de brusques hausses de temperature; Issledovanie reaktsii metallov s soedineniyami sery i fosfora pri regulyarnykh izmeneniyakh temperatury; Estudio de reacciones entre metales y compuestos de azufre y de fosforo empleando impulsos de temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, R B; Grunberg, L [National Engineering Laboratory, East Kilbride, Glasgow (United Kingdom)

    1962-01-15

    The anti-wear action of sulphur and phosphorus compounds which are usually added to gear-oils depends on chemical reactions with the metallic surfaces of the gears. These reactions occur both at the bulk oil temperature (approx. 100 Degree-Sign C) and during high temperatures (approx. 600 Degree-Sign C) of short duration when the gearteeth come into contact under lead. The temperature flashes were simulated in an apparatus in which short pulses of electric current were used to heat metal wires immersed in mineral oil containing S{sup 35} and P{sup 32} labelled compounds in solution. The radioactivity acquired by the wires was measured. The extent of the reactions was determined as a function of temperature and time and the results were interpreted in terms of conventional kinetic laws. The modification of the reaction rates by the presence of other compounds in the solution was studied. The effect of pre-formed surface films containing sulphur phosphorus, chlorine and/or oxygen was also determined. In explaining the results, the structure of the materials used and the diffusion processes whereby the reactions occur beyond the initial stages were considered. (author) [French] Les composes du soufre et du phosphore que l'on ajoute souvent aux huiles de graissage offrent une protection contre l'usure, mais cette protection depend des reactions chimiques avec les surfaces metalliques des engrenages. Ces reactions ont lieu aussi bien a la temperature de la masse de l'huile (environ 100 Degree-Sign C) qu'au moment des brusques hausses de temperature (environ 600 Degree-Sign C) qui se produisent lorsque les dents d'engrenage viennent en contact avec pression. Les chocs thermiques ont ete simules dans un appareil a l'interieur duquel on a produit de breves impulsions de courant electrique pour chauffer des fils metalliques immerges dans une huile minerale contenant des composes marques au soufre-35 et au phosphore-32 en solution. Les auteurs ont mesure la radioactivite

  8. Au-delà de la relation « bourreau-victime » dans l’analyse d’une situation de harcèlement psychologique au travail

    Directory of Open Access Journals (Sweden)

    Michel Vézina

    2005-11-01

    Full Text Available Des dispositions législatives ont été adoptées dans plusieurs pays, afin de contrer le harcèlement psychologique au travail. Même s’il est souvent nécessaire, d’un point de vue juridique, que les mesures portent sur la protection individuelle des victimes, on ne peut penser endiguer ce fléau en ne s’appuyant que sur une approche centrée sur l’individu. Aussi, au-delà d’une approche « bourreau-victime » à courte vue, la prévention véritable du harcèlement psychologique au travail passe-t-elle par l’analyse et l’élimination des facteurs organisationnels et des éléments culturels qui constituent un terreau fertile ou propice à l’émergence de comportements violents entre membres d’une même organisation de travail. Ces facteurs sont notamment l’intensification du travail, la faiblesse de l’autorité hiérarchique et la précarisation du lien d’emploi, de même que la banalisation ou la négation du phénomène, la tolérance aux incivilités et l’iniquité ou l’injustice en milieu de travail. À l’instar de la technique de l’arbre des causes utilisée dans l’investigation d’un accident de travail, les intervenants confrontés à une situation de harcèlement psychologique au travail sont invités à adopter une approche qui va au-delà des évidences premières, pour s’attaquer aux causes plus indirectes du phénomène, soit les lacunes dans le système de gestion.Legislation has been adopted in several countries to counter psychological harassment in the workplace. Even if it is often necessary, from a legal standpoint, that the means involve the personal protection of victims, more than a person-centred approach must be considered for stopping this wrong. Also, beyond a « bully-victim » approach, in the short view, real prevention of workplace psychological harassment is achieved by analyzing and eliminating organizational factors and cultural aspects that constitute a fertile

  9. Study of the influence of the fast neutron spectrum on the production of defects in solids and liquids; Etude de l'influence du spectre des neutrons rapides sur la creation de defauts dans les solides et les liquides

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    In the first part of this work a calculation has been made of the number of defects formed in graphite by a given neutron flux having various spectral distributions. The defect formation function is that of KINCHIN and PEASE; its formulation is briefly given. An efficiency function is then defined for a fast neutron spectrum. This defects produced in a light water reactor and those produced in a graphite reactor. Finally an application of this method is given for comparing the defect forming tendency in graphite in the case of the reactor Melusine and of the reactor G-2 and G-3. In the second part are calculated the integrals for the energy release brought about by fast neutrons in carbon oxygen and hydrogen. In a region of 25 cm around the core of a swimming-pool type reactor these energy release integrals are approximately proportional to the neutron flux above 1 MeV. The determination of the energy released as a result of the passage of neutrons in organic liquids can therefore be reduced to the measurement of the flux above 1 MeV for the real spectral distribution. A calorimetric verification has been carried out in the case of water. (authors) [French] Dans la premiere partie de cette etude, on a calcule le nombre de defauts crees dans le graphite par un flux de neutrons donne, pris sous differents spectres. On a ainsi fait les calculs pour 4 spectres de pile. piscine et 2 spectres de pile au graphite. La fonction creation de defauts est celle de KINCHIN et PEASE. On rappelle brievement sa formulation. Puis on definit une fonction efficacite d'un spectre de neutrons rapides. Cette fonction permet alors d'etablir la relation entre defauts crees dans une pile a eau legere et defauts crees dans une pile au graphite. Enfin, une application de cette methode est donnee pour comparer l'aptitude a creer les defauts dans le graphite par la pile MELUSINE et les piles G-2 ou G-3. Dans la deuxieme partie, on a calcule les integrales de degagement d'energie provoque par

  10. Underground nuclear explosions. Geological survey of the cavities; Explosions nucleaires souterraines etude geologique des cavites

    Energy Technology Data Exchange (ETDEWEB)

    Faure, J [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    A geological survey of underground nuclear explosions makes it possible to determine the main characteristics of the cavity formed. The lower portion is spherical; the same was very likely true of the roof, which collapses in the majority of media with the exception of rock-salt. Its radius, for a given bomb size, can vary by a factor of two according to the type of rock. The lay-out of its contents depends on the characteristics of the solid and liquid products at the moment of the roof collapse; according to the medium involved, mixing of the rubble and the mud-flow occurs (granite) or does not occur (tuff and alluvia). In all media, the average physical properties can be evaluated. (author) [French] L'etude geologique d'explosions nucleaires souterraines permet de determiner les principaux caracteres de la cavite creee. Sa partie inferieure est spherique; il en etait vraisemblablement de meme de sa voute, effondree dans la plupart des milieux a l'exception du sel gemme. Son rayon, a energie d'engin egale, varie selon les roches du simple au double. La disposition de son contenu depend des caracteristiques des produits solides et liquides au moment de la chute du toit; selon le cas, il n'y a pas (tuf et alluvions) ou il y a (granite) melange des eboulis et des laves. Dans tous les milieux, les proprietes physiques moyennes peuvent etre evaluees. (auteur)

  11. Ultra-relativistic Au+Au and d+Au collisions:

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    In this talk I will review PHOBOS data on charged particle multiplicities, obtained in Au+Au and d+Au collisions at RHIC. The general features of the Au+Au pseudorapidity distributions results will be discussed and compared to those of /line{p}p collisions. The total charged particle multiplicity, scaled by the number of participant pairs, is observed to be about 40% higher in Au+Au collisions than in /line{p}p and d+Au systems, but, surprisingly at the same level of e+e- collisions. Limiting fragmentation scaling is seen to be obeyed in Au+Au collisions.

  12. Absolute measurement of {beta} emitters with a 4 {pi} counter; Mesure absolue des emetteurs {beta} au compteur 4 {pi}

    Energy Technology Data Exchange (ETDEWEB)

    Le Gallic, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-06-15

    The object of this work is to investigate the conditions under which the activity of {beta}-emitting radionuclides may be measured with a maximum of precision, and as a result to study the relevant corrections. The various problems relating to activity measurements with a 4 {pi} counter have been examined successively: - comparison of 4 {pi}, GM and proportional counters; - study of the preparation of sources; - corrections on the counting of sources; - self-absorption; - correction for absorption. The precision obtained on these measurements varies from 1.2 to 3 per cent, with the result that the 4 {pi} counter can be considered a very satisfactory calibration instrument. (author) [French] Le but de ce travail est de rechercher les conditions permettant d'obtenir avec le maximum de precision, la mesure de l'activite des radionuclides se desintegrant par emission et par consequent d'etudier les corrections qui s'y rapportent. Nous avons examine successivement les differents problemes se rapportant aux mesures d'activite au compteur 4 {pi}: - Comparaison des compteurs 4 {pi}, GM et proportionnel; - etude de la preparation des sources; - corrections sur la numeration des sources; - auto-absorption; - correction d'absorption. La precision obtenue dans ces mesures, variant de 1,2 a 3 pour cent, on peut donc considerer le compteur 4 {pi} comme un instrument d'etalonnage tres satisfaisant. (auteur)

  13. Absolute measurement of {beta} emitters with a 4 {pi} counter; Mesure absolue des emetteurs {beta} au compteur 4 {pi}

    Energy Technology Data Exchange (ETDEWEB)

    Le Gallic, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-06-15

    The object of this work is to investigate the conditions under which the activity of {beta}-emitting radionuclides may be measured with a maximum of precision, and as a result to study the relevant corrections. The various problems relating to activity measurements with a 4 {pi} counter have been examined successively: - comparison of 4 {pi}, GM and proportional counters; - study of the preparation of sources; - corrections on the counting of sources; - self-absorption; - correction for absorption. The precision obtained on these measurements varies from 1.2 to 3 per cent, with the result that the 4 {pi} counter can be considered a very satisfactory calibration instrument. (author) [French] Le but de ce travail est de rechercher les conditions permettant d'obtenir avec le maximum de precision, la mesure de l'activite des radionuclides se desintegrant par emission et par consequent d'etudier les corrections qui s'y rapportent. Nous avons examine successivement les differents problemes se rapportant aux mesures d'activite au compteur 4 {pi}: - Comparaison des compteurs 4 {pi}, GM et proportionnel; - etude de la preparation des sources; - corrections sur la numeration des sources; - auto-absorption; - correction d'absorption. La precision obtenue dans ces mesures, variant de 1,2 a 3 pour cent, on peut donc considerer le compteur 4 {pi} comme un instrument d'etalonnage tres satisfaisant. (auteur)

  14. Etude des facteurs liés à l'observance au traitement antirétroviral chez les patients suivis à l'Unité de Prise En Charge du VIH/SIDA de l'Hôpital de District de Dschang, Cameroun

    Science.gov (United States)

    Mbopi-Kéou, François-Xavier; Dempouo Djomassi, Lucienne; Monebenimp, Francisca

    2012-01-01

    Introduction Etudier les facteurs liés à l'observance au traitement antirétroviral chez les patients adultes suivis à l'Unité de Prise en Charge du VIH/SIDA (UPEC) de l'hôpital de District de Dschang. Méthodes Dans une étude descriptive transversale conduite à l'hôpital de District de Dschang, l'observance a été évaluée sur la base des déclarations des patients et sur la régularité du renouvellement de leurs ordonnances (observance calculée). Résultats Parmi les 389 patients répondant à nos critères d'inclusion, 356 ont été interrogés. La durée moyenne du suivi était de 27 mois. La moyenne d’âge était égale à 41 ans et le sexe ratio 2,46 en faveur du sexe féminin. Le statut sérologique était découvert pour 60,56% des patients à l'occasion d'un épisode maladif. Le niveau d'observance déclarée était significativement plus élevé que le niveau global de l'observance calculée (80,2% vs 51,5%, p<10−5). Les deux principales barrières à l'observance étaient l'oubli et le travail. Les patients référés dans cette UPEC étaient moins bien observants (p<10−4). L'observance au traitement antirétroviral était d'autant meilleure quand le taux de CD4 en début de traitement était élevé (p= 0,01) et que la durée du traitement était prolongée (p=0,00). Conclusion La discordance observée entre les résultats des deux méthodes utilisées pour estimer l'observance, tout en soulévant les contraintes liées à l’évaluation de l'observance thérapeutique, souligne l'importance des méthodes biologiques. Les facteurs individuels se sont avérés être les principales raisons de non-observance. Enfin, un accent devrait être mis sur les consultations d’éducation thérapeutique et le suivi psycho-social des patients sous traitement antirétroviral dans cette UPEC. PMID:22937195

  15. Study of water radiolysis in relation with the primary cooling circuit of pressurized water reactors; Etude sur la radiolyse de l`eau en relation avec le circuit primaire de refroidissement des reacteurs nucleaires a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Pastina, B

    1997-07-01

    This memorandum shows a fundamental study on the water radiolysis in relation with the cooling primary circuit of PWR type reactors. The water of the primary circuit contains boric acid a soluble neutronic poison and also hydrogen that has for role to inhibit the water decomposition under radiation effect. In the aim to better understand the mechanism of dissolved hydrogen action and to evaluate the impact of several parameters on this mechanism, aqueous solutions with boric acid and hydrogen have been irradiated in a experimental nuclear reactor, at 30, 100 and 200 Celsius degrees. It has been found that, with hydrogen, the water decomposition under irradiation is a threshold phenomenon in function of the ratio between the radiation flux `1` B(n, )`7 Li and the gamma flux. When this ratio become too high, the number of radicals is not sufficient to participate at the chain reaction, and then water is decomposed in O{sub 2} and H{sub 2}O{sub 2} in a irreversible way. The temperature has a beneficial part on this mechanism. The iron ion and the copper ion favour the water decomposition. (N.C.). 83 refs.

  16. Methods for studying the radioactive contamination of plants (1963); Methodes d'etude de la contamination radioactive des vegetaux (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Coulon, R; Jeanmaire, L; Michon, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1963-07-01

    The authors first define the doctrine which led to the devising of a method for studying the radioactive pollution of plants, based on the use of simple techniques, having the possibility of being adapted for routine work, and so devised that each stage is proceeded with only if the preceding one justifies it. For each stage a study is effected comparing the results obtained by the use of more exact techniques. The second part describes in detail the techniques used. (authors) [French] Dans une premiere partie lea auteurs definissent la doctrine qui leur a permis d'elaborer une methode d'etude de la pollution radioactive des vegetaux, basee sur l'utilisation de techniques simples, se pretant au travail de serie et concues de telle maniere que chaque etape n'est abordee que si la precedente le justifie. Chaque etape fait l'objet d'une etude qui compare les resultats a ceux obtenue par des techniques plus precises. La deuxieme partie decrit dans le detail les techniques utilisees. (auteurs)

  17. Study of a method of detection for natural carbon-14 using a liquid scintillator, recent variations in the natural radio-activity due to artificial carbon-14 (1963); Etude d'une methode de detection du carrons 14 naturel, utilisant un scintillateur liquide - variations recentes de l'activite naturelle dues au carbone 14 artificiel (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-06-15

    Among the various natural isotopes of carbon, a radioactive isotope, carbon-14, is formed by the action of secondary neutrons from cosmic rays on nitrogen in the air. Until 1950, the concentration of this isotope in ordinary carbon underwent weak fluctuations of about 2-3 per cent. The exact measurement of this concentration 6 X 10{sup 12} Ci/gm of carbon, and of its fluctuations, are difficult and in the first part of this report a highly sensitive method is given using a liquid scintillator. Since 1950 this natural activity has shown large fluctuations because of the carbon-14 formed during nuclear explosions, and in the second part, the evolution in France of this specific activity of carbon in the atmosphere and biosphere is examined. In the last part is studied the local increase in carbon activity in the atmosphere around the Saclay site, an increase caused by the carbon-14 given off as C{sup 14}O{sub 2}, by the reactors cooled partially with exterior air. (author) [French] Parmi les differents isotopes naturels du carbone, un isotope radioactif, le carbone 14, est forme par l'action de neutrons secondaires due aux rayons cosmiques sir l'azote de l'air. Jusqu'en 1950, la concentration de cet isotope dans le carbone ordinaire est soumise a des fluctuations de faible amplitude, de l'ordre de 2 a 3 pour cent. Les mesures precises de cette concentration, 6. 10{sup -12} Ci/g de carbone, et de ses fluctuations sont delicates, et dans la premiere partie de ce rapport, on decrit une methode de detection a grande sensibilite utilisant un scintillateur liquide. Depuis 1950, cette activite naturelle subit des fluctuations importantes dues au carbone 14 forme lors des explosions nucleaires, et dans la seconde partie, on examine l'evolution en France de l'activite specifique du carbone de l'atmosphere et ce la biosphere. Dans la derniere partie, on etudie l'accroissement local de l'activite du carbone de l'air aux environs du site de Saclay, accroissement provoque par le

  18. Study of a method of detection for natural carbon-14 using a liquid scintillator, recent variations in the natural radio-activity due to artificial carbon-14 (1963); Etude d'une methode de detection du carrons 14 naturel, utilisant un scintillateur liquide - variations recentes de l'activite naturelle dues au carbone 14 artificiel (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-06-15

    Among the various natural isotopes of carbon, a radioactive isotope, carbon-14, is formed by the action of secondary neutrons from cosmic rays on nitrogen in the air. Until 1950, the concentration of this isotope in ordinary carbon underwent weak fluctuations of about 2-3 per cent. The exact measurement of this concentration 6 X 10{sup 12} Ci/gm of carbon, and of its fluctuations, are difficult and in the first part of this report a highly sensitive method is given using a liquid scintillator. Since 1950 this natural activity has shown large fluctuations because of the carbon-14 formed during nuclear explosions, and in the second part, the evolution in France of this specific activity of carbon in the atmosphere and biosphere is examined. In the last part is studied the local increase in carbon activity in the atmosphere around the Saclay site, an increase caused by the carbon-14 given off as C{sup 14}O{sub 2}, by the reactors cooled partially with exterior air. (author) [French] Parmi les differents isotopes naturels du carbone, un isotope radioactif, le carbone 14, est forme par l'action de neutrons secondaires due aux rayons cosmiques sir l'azote de l'air. Jusqu'en 1950, la concentration de cet isotope dans le carbone ordinaire est soumise a des fluctuations de faible amplitude, de l'ordre de 2 a 3 pour cent. Les mesures precises de cette concentration, 6. 10{sup -12} Ci/g de carbone, et de ses fluctuations sont delicates, et dans la premiere partie de ce rapport, on decrit une methode de detection a grande sensibilite utilisant un scintillateur liquide. Depuis 1950, cette activite naturelle subit des fluctuations importantes dues au carbone 14 forme lors des explosions nucleaires, et dans la seconde partie, on examine l'evolution en France de l'activite specifique du carbone de l'atmosphere et ce la biosphere. Dans la derniere partie, on etudie l'accroissement local de l'activite du carbone de l'air aux

  19. Theoretical and experimental study of heat transfers and pressure drops along surfaces fitted with herring-bone fins: correlation between geometric and aero thermal parameters; Etudes theorique et experimentale du transfert de chaleur et des pertes de charge de surfaces munies d'ailettes disposees en chevron - correlation entre parametres geometriques et aerothermiques

    Energy Technology Data Exchange (ETDEWEB)

    Pelce, J; Malherbe, J; Pierre, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Principal results are given of experimental research which has been carried out on the flow of a fluid along a surface fitted with herringbone fins. Aero-thermal tests have been effected on a large number of these surfaces whose geometrical parameters have been made to vary systematically. In particular, work on a large scale model has made it possible to analyse the mechanisms of heat transfer and of pressure drops. On this basis a theoretical study has led to the establishment of a correlation between the geometric configuration and the aero-thermal performances of these surfaces. Experimental results are in good agreement with the theoretical relationships. An expression has thus been derived applicable to this type of herring-boned surface in a wide zone. (authors) [French] L'ecoulement d'un fluide au voisinage d'une surface munie d'ailettes disposees en chevron a fait l'objet de recherches experimentales dont on a rappele les principaux resultats. Des essais aerothermiques ont ete effectues sur un grand nombre de ces surfaces dont a fait varier les parametres geometriques de facon systematique. En particulier, des etudes sur une maquette a grande echelle ont permis d'analyser les mecanismes de transfert de chaleur et de perte de charge. Sur ces bases, une etude theorique a conduit a des correlations entre la geometrie et les performances aerothermiques de ces surfaces. Les resultats experimentaux sont en bon accord avec les relations theoriques. On possede ainsi une formulation pour ce type de surface ailettee valable dans un domaine etendu. (auteurs)

  20. A study of the fluorescence of the rare gases excited by nuclear particles. Use of the principle for the detection of nuclear radiation by scintillation; Etude de la fluorescence des gaz rares excites par des particules nucleaires. Utilisation pour la detection des rayonnements nucleaires par scintillation

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-12-15

    In the first part is studied the properties of atoms excited by the passage of {alpha} particles through the various rare gases at atmospheric pressure. A spectral analysis of the emitted light showed that certain impurities play an important part in producing the fluorescence, and it has led to the conclusion that the light emission contains at least two components - one very short - lived due to the direct deexcitation of the rare gas, the other relatively slower due to the energy transfers to the impurity. The measurement of the life-time of the excited states has confirmed this foregoing hypothesis, the rapid part of the impulse is extremely short: less than 2,25.10{sup -9} s in the case of xenon; the slower part has a life-time depending directly on the nitrogen concentration, nitrogen being the impurity giving the largest effect in all cases. The study of rare gases under the influence of an electric field has made it possible to show that the amount of light produced by an {alpha} particle can be multiplied (by 60, for example, in a field of 600 V:cm) so that the luminescent efficiency is greater than in the case of INaTI. In the second part the characteristics of the rare gases acting as scintillators is examined, the most important property being the absence of fluorescence saturation when the intensity of the excitation incident on the gas is very large. This, together with the very short time of scintillation has made it possible to study a certain number of nuclear physical applications (heavy particle energy-measurements, kinetic studies on nuclear reactors, neutron spectroscopy). (author) [French] On etudie dans la premiere partie les proprietes des atomes excites par le passage de particules {alpha} dans les differents gaz rares a la pression atmospherique. L'etude spectrale de la lumiere emise a montre que certaines impuretes jouent un role considerable dans la fluorescence et on a ete amene a penser que l'emission de lumiere comporte au moins deux

  1. Contribution to the study of turbulent flow in cylindrical tubing with porous walls; Contribution a l'etude de l'ecoulement turbulent dans une conduite cylindrique a paroi poreuse

    Energy Technology Data Exchange (ETDEWEB)

    Burnage, H

    1962-07-01

    A theoretical study has been made of a fully developed turbulent flow in cylindrical tubing of circular cross-section subjected to a uniform suction through the walls. This study has made it possible to find a relationship giving the friction coefficient at the wall in terms of the amount of local suction and of the longitudinal static pressure gradient. A method for calculating the Reynolds tensions from the pressure measurements has been devised. An experimental system has been developed. Pressure measurements have been made. By using experimental results it has been possible to obtain a semi empirical expression for the friction coefficient at the wall, in terms of the amount of suction of the inlet Reynolds number, and of the abscissa. (author) [French] Une etude theorique de refoulement turbulent pleinement developpe dans une conduite cylindrique de section circulaire soumise a une aspiration parietale uniforme a ete entreprise. Elle a permis de trouver une relation donnant le coefficient de frottement a la paroi en fonction du taux d'aspiration local et du gradient de pression statique longitudinal. Une methode de calcul des tensions de Reynolds a partir des mesures de pression a ete etablie. Un dispositif experimental a ete realise et mis au point. Des mesures de pression ont ete effectuees. L'utilisation des resultats experimentaux a permis d'obtenir une expression semi-empirique du coefficient de frottement a la paroi en fonction du taux d'aspiration, du nombre de Reynolds d'entree et de l'abscisse. (auteur)

  2. Study of the low temperature oxidation of uranium powders and its application to the sintering of uranium oxide powders; Etude de l'oxydation des poudres dtranium a basse temperature et son application au frittage de poudres d'uranium oxyde

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-06-01

    techniques utilisees sont la micrographie, la thermogravimetrie, le frittage sous charge, la radiocristallographie. A 170 deg. C, sous air ou dans des melanges argon + oxygene, l'oxyde d'uranium forme est toujours UO{sub 2} et il est uniformement reparti autour des billes d'uranium de depart. Ces poudres mixtes se frittent facilement sous charge en phase {gamma}. On obtient des echantillons dont la densite est de 85 a 90 pour cent de la densite theorique. L'influence de l'UO{sub 2} sur les proprietes de l'uranium a ete mise en evidence par dilatometrie et cyclage thermique en phase {alpha}. Les temperatures des changements de phase {alpha} {r_reversible} {beta}, {beta} {r_reversible} {gamma} sont abaissees, l'allongement remanent est diminue. Les echantillons de bonne densite ont une bonne tenue au cyclage thermique; les defauts caracteristiques de l'uranium: grande distorsion, peau d'orange, n'existent presque plus. Des traitements thermiques sous vide secondaire a 1050 deg. C provoquent la cristallisation de l'UO{sub 2} sous forme geometrique et l'apparition d'une phase, de systeme cristallin C.F.C., de formule U{sub W}C{sub X}O{sub Y}N{sub Z}. Cette phase provoque un nouvel abaissement des temperatures de transformation {alpha} {r_reversible} {beta}, {beta} {r_reversible} {gamma} de l'uranium. Apres dix cycles dilatometriques, l'allongement remanent de l'echantillon est de l'ordre de 0,5 pour cent. La tenue au cyclage thermique d'un echantillon de faible densite ayant ete traite thermiquement est comparable a celle d'un echantillon de bonne densite n'ayant pas subi de traitement thermique. (auteur)

  3. 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

  4. 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

  5. Study of new structures adapted to gas-graphite and gas-heavy water reactors; Etude de structures nouvelles adaptees aux reacteurs graphite-gaz et eau lourde-gaz

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    'EDF d'une part, les conclusions des etudes et essais effectues hors pile d'autre part, conduisent a un changement considerable de la physionomie des reacteurs de la filiere Graphite-Gaz, Les principales modifications envisagees sont analysees dans la communication. L'adoption d'un element combustible annulaire et d'un soufflage descendant permettront d'accroitre considerablement la puissance specifique et la puissance developpee par canal; il en resultera une reduction sensible du nombre des canaux et un accroissement correlatif de la maille du reseau - L'empilement de graphite devra etre adapte a ces nouvelles conditions - Des raisons de securite conduisent a generaliser l'emploi du beton precontraint pour la construction du caisson; elles pourront amener a integrer a l'interieur de celui-ci les echangeurs et l'appareil de manutention du combustible (dispositif dit: 'en grenier'). Une maquette en vraie grandeur de ce grenier a ete construite a Saclay avec la participation d'EURATOM; les resultats d'exploitation en sont presentes, ainsi que des idees de barres de controle de conception nouvelle. En ce qui concerne la filiere Eau-Lourde-Gaz, les etudes sont poursuivies dans deux voies principales; la premiere, qui conserverait l'usage de tubes de force horizontaux, tient compte de l'experience acquise au cours de la construction du reacteur EL4 dont elle constituerait une extrapolation; la seconde, inspiree des etudes poursuivies au titre de la filiere Graphite-Gaz, ferait appel a un caisson en beton precontraint pour tenir la pression, le moderateur etant sensiblement a la pression du fluide refrigerant et le combustible etant dispose dans des canaux verticaux. Les merites respectifs de ces deux variantes sont analyses dans la communication. (auteurs)

  6. φ meson production in Au + Au and p + p collisions at √sNN=200 GeV

    International Nuclear Information System (INIS)

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G.S.; Badyal, S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj, S.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Carroll, J.; Castillo, J.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Ganti, M.S.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grebenyuk, O.; Gronstal, S.; Grosnick, D.; Guedon, M.; Guertin, S.M.; Gupta, A.; Gutierrez, T.D.; Hallman, T.J.; Hamed, A.; Hardtke, D.; Harris, J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang, S.L.; Hughes, E.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaplan, M.; Keane, D.; Khodyrev; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Kopytine, S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Kravstov, V.I.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.Kh.

    2004-01-01

    We report the STAR measurement of ψ meson production in Au + Au and p + p collisions at √s NN = 200 GeV. Using the event mixing technique, the ψ spectra and yields are obtained at midrapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the ψ transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that ψ production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions ( bin >). The systematics of T > versus centrality and the constant ψ/K - ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for ψ production

  7. Mise au point

    African Journals Online (AJOL)

    31 mai 2013 ... traités au service de chirurgie maxillo-faciale et chirurgie plastique de l'hôpital ... qui est la fracture simple isolée du corps, on a inclut ce type de fracture ... sion latérale au niveau de la queue du sourcil. La voie vestibulaire ...

  8. Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras

    Energy Technology Data Exchange (ETDEWEB)

    DeHaan, A. Jr.; Leventhal, L.; Benson, P. [Tracerlab, Richmond, CA (United States)

    1965-10-15

    analysis. Statistical estimates for the errors in the resulting concentration of the radionuclides are provided for each analytical method when they are applied to multicomponent radionuclide mixtures. (author) [French] La resolution du rayonnement de melanges oomplexes d'emetteurs gamma a ete facilitee par l'emploi de spectrometres gamma tres perfectionnes et de calculatrices numeriques. Ces appareils sont maintenant a la disposition de presque tousles laboratoires techniques. Les auteurs etudient les techniques utilisees dans leur laboratoire pour mesurer les concentrations individuelles de differents radionucleides emetteurs gamma dans des echantillons provenant de retombees radioactives et comparent les resultats obtenus par les differentes methodes mathematiques avec des echantillons de composition complexe. Les donnees fournies par l'ordinateur sont comparees avec les resultats obtenus par analyse radiochimique de l'echantillon. Apres avoir analyse des composes binaires au moyen des methodes decrites ci-apres, les auteurs ont etendu l'analyse aux emetteurs composes de nombreux elements. Ils ont mis au point une methode avec ordinateur qui normalise les spectres gamma de maniere a reduire au minimum le glissement a long terme du spectrometre et qui convertit le spectre en une configuration dont l'energie est l'une des coordonnees. Ils etudient par les diverses methodes ci-apres les effets d'un 'pic photoelectrique imprevu ', d'un element d'intensitezero et de la superposition de pics, en particulier dans le cas d'echantillons de faible activite. Les auteurs ont analyse les methodes mathematiques les plus courantes pour la resolution des diverses composantes d'un spectre gamma complexe. La plupart de ces methodes aboutissent a une evaluation des concentrations de differents emetteurs gamma par l'un des procedes suivants: 1. Elimination successive des radionucleides a pic photoelectrique de forte energie, le spectre pur etant extrait du spectre compose jusqu

  9. Applicability of ICRP principles for safety analysis of radioactive waste geological storage; Etude de l'applicabilite des principes de la CIPR a l'analyse de surete du stockage geologique des dechets radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Lombard, J; Hubert, P; Pages, P

    1987-07-01

    modalites de stockage) doit etre determine par un processus comparatif visant a selectionner le niveau conduisant au meilleur compromis entre es depenses de protection et les risques residuels. Ces recommandations, particulierement Ia seconde, s'ecartent des principes des analyses de surete suivis jusqu'a present en France et a l'etranger; cette etude envisage les avantages et inconvenients potentiels lies a l'introduction de ce second principe. Dans ce but on se base sur differentes analyses realisees au niveau international integrant partiellement au moms ces principes. II ressort de cet examen que ces principes sont applicables mais que leur mise en oeuvre necessite une reorientation de modeles d'evaluation en particulier pour s'affranchir d'hypotheses trop conservatrices. Cette mise en oeuvre necessite par ailleurs davantage d'informations que dans le cas d'une approche deterministe de Ia surete puisqu'il faut estimer les consequences et les probabilites de I'ensemble des evenements possibles et ce pour es diverses modalites de stockage que l'on se propose de comparer. L'integration d'evaluation de ce type est cependant plus riche d'enseignements et constitue de ce fait une aide a Ia decision qui peut etre feconde. On peut enfin souligner que cette approche permet un meilleur dialogue entre les differentes instances decisionnelles et plus generalement entre les acteurs du debat, dans Ia mesure ou elle apporte un langage de discussion commun. On notera d'ailleurs que ce souci de clarification s'exprime quelle que soit I'optique de surete adopte (deterministe ou probabiliste), comme en temoignent les interrogations sur le sens du 'scenario central' de I'etude KBS. Par ailleurs, ii semble que ces principes seront vraisemblablement suivis au plan international afin d'uniformiser en outre les modes de gestion de Ia radioprotection dans ses diff?rentes composantes. (author)

  10. Some techniques for studying actomyosin by electron microscopy; Quelques techniques d'etude de l'actomyosine par microscopie electronique

    Energy Technology Data Exchange (ETDEWEB)

    Herzberg, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Departement de Biologie

    1967-07-01

    A method has been developed for shadowing using a platinum-carbon alloy; it has been applied to the study of the interaction of actomyosin with its substrate ATP. The results obtained seem to favour the hypothesis of a dissociation of the actomyosin into its two components: actin and myosin. Pictures have been obtained showing particles resembling non-polymerized myosin but no rigorous proof of this exists. (author) [French] Une methode d'ombrage par un alliage de platine et carbone a ete mise au point et appliquee a l'etude de l'interaction de l'actomyosine et de son substrat l'ATP. Les resultats obtenus semblent pencher en faveur de la these d'une dissociation de l'actomyosine en ses deux constituants: l'actine et la myosine. Des images ont ete obtenues montrant des particules dont l'identite avec la myosine non polymerisee reste a demontrer plus rigoureusement. (auteur)

  11. Contribution to the study of the diffusion of fission products in uranium; Contribution a l'etude de la diffusion des produits de fission dans l'uranium

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-10-15

    In this work we have developed a simple method for determining the diffusion constants and the solid-state solubilities of a metal which is volatile and only slightly soluble in second metal. This method has been applied to the behaviour of certain fission products in {gamma} uranium: strontium, barium, lanthanum, samarium and cerium. This work has made it possible to show the effect of the atomic radius of the solute on the diffusion constants. (author) [French] Dans ce travail nous avons mis au point une methode simple permettant de determiner les constantes de diffusion ainsi que les solubilites a l'etat solide d'un metal volatil et peu soluble dans un autre. Cette methode a ete appliquee au comportement de certains produits de fission dans l'uranium {gamma}: strontium, baryum, lanthane, samarium et cerium. Cette etude a permis de mettre en evidence le role du rayon atomique du solute sur les constantes de diffusion. (auteur)

  12. Solidification of residual fission-product solutions; laboratory studies; Solidification de solutions residuaires concentrees de produits de fission: etudes de laboratoire

    Energy Technology Data Exchange (ETDEWEB)

    Boniaud, R; Cohen, P; Sombret, C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    This paper describes the results obtained, at laboratory scale, during the study of the incorporation of fission products into glasses and synthetic micas. The rate of leaching of fission products from the glass and their volatility during firing were measured. A hot cell was built to complete these results. (author) [French] Ce rapport resume le resultat des etudes faites en laboratoire (activite de l'ordre du millicurie) sur l'incorporation des produits de fission dans des verres et micas synthetiques. On a mesure le taux de lixiviation des produits de fission et leur volatilisation au cours de la cuisson. Une cellule chaude a ete installee pour completer ces resultats au moyen d'essais realises avec une activite superieure. (auteur)

  13. E. P. R. spectroscopic study of nitroxide mono- and bi-radicals; Etude par spectroscopie de resonance paramagnetique electronique de monoradicaux et de biradicaux nitroxydes

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, H [Commissariat a l' Energie Atomique, Grenoble, 38 (France). Centre d' Etudes Nucleaires

    1967-07-01

    A nitroxide is a molecule containing the group N-O where the oxygen atom made only one bond instead of the usual two. The main advantage of these radicals is their exceptional stability; this allows the study of well defined chemical structures while varying at will the experimental conditions. Studies by electron paramagnetic resonance of nitroxide mono-radicals have given the principal directions and the principal values of the electron-nitrogen nucleus hyperfine tensor and of the anisotropic g-factor tensor. The results were then related to the electronic structure of radicals. An understanding was obtained of the influence of the solvent on the principal values of the tensors, and the marked differences observed in the broadening of hyperfine lines when the medium become viscous. In the nitroxide biradicals, the hyperfine spectra depends not only on the magnetic interactions relative to each monomer, but also on the magnitude of the exchange interaction between the singlet and the triplet states of the dimer; the biradicals studied here are the first organic compounds which show clearly the influence of this exchange on the hyperfine structure. The two unpaired electrons also interact by a magnetic dipolar interaction: in the intermediate case, this can be used to derive the sign of the exchange interaction if the bi-radical is studied in a liquid crystal. Just as for mono-radicals, the hyperfine spectra of bi-radicals show selective broadening in viscous media, which is caused by an overall motional modulation of the anisotropic tensors. This gives another way to determine the sign of the exchange interaction. (author) [French] On appelle nitroxyde une molecule contenant le groupement N-O ou l'atome d'oxygene n'a satisfait qu'une seule liaison de valence sur les deux qui lui sont habituelles. L'interet majeur de ces radicaux reside dans leur exceptionnelle stabilite, permettant ainsi de faire varier a loisir les conditions experimentales d'etude de produits

  14. Spectroscopic study of near closed-shell nuclei Z = 50, by means of the ({sup 3}He,d) and (d, {sup 3}He) reactions on all even tin isotopes, and the ({sup 3}He, d) reaction on the A = 113 and A = 115 indium isotopes; Etude spectroscopique des noyaux au voisinage de la couche fermee Z = 50, au moyen des reactions ({sup 3}He, d) et (d, {sup 3}He) sur tous les isotopes pairs de l'etain, et de la reaction ({sup 3}He, d) sur les isotopes 113, 115 de l'indium

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-06-01

    A systematic study of ({sup 3}He, d) reactions at 18 MeV incident energy and (d, {sup 3}He) reactions at 22 MeV incident energy on {sup 112,114,116,118,120,122,124}Sn is presented. The distorted wave Born approximation (DWBA) is used to extract informations on (a) the transferred angular momentum l{sub p}, (b) the change of parity and (c) the spectroscopic factor. We have investigated the influence of the proton-neutron residual interaction on the spread of the pure proton configuration (particle or hole), and on the observed level sequence. Experimental results and predictions of the Kisslinger and Sorensen model are in reasonable agreement. A study of {sup 113,115}In ({sup 3}He, d) {sup 114,116}Sn reactions shows strong experimental evidence that the proton particle hole components are weak in the first excited states of tin nuclei. Furthermore, highly excited states ({approx} 4 to 6 MeV) having a simple structure with one predominant particle-hole configuration have been located. (authors) [French] Nous presentons une etude systematique des reactions ({sup 3}He, d) a 18 MeV et (d, {sup 3}He) a 22 MeV sur {sup 112,114,116,118,120,122,124}Sn. L'approximation des ondes deformees (DWBA) est utilisee pour obtenir des informations sur le moment angulaire transfere l{sub p}, sur le changement de parite et le facteur spectroscopique. Nous avons etudie l'influence de l'interaction residuelle proton-neutron sur la repartition de l'intensite a une seule particule ou trou de proton, et sur les sequences des niveaux observes. Les resultats experimentaux et les previsions theoriques du modele de Kisslinger et Sorensen sont en assez bon accord. L'etude des reactions {sup 113,115}In ({sup 3}He, d) {sup 114,116}Sn apporte la preuve experimentale que les composantes particule - trou de protons des premiers etats excites des noyaux residuels sont faibles. Elle permet aussi de localiser des niveaux a une energie d'excitation elevee ({approx} 4 a 6 Me

  15. Spectroscopic study of near closed-shell nuclei Z = 50, by means of the ({sup 3}He,d) and (d, {sup 3}He) reactions on all even tin isotopes, and the ({sup 3}He, d) reaction on the A = 113 and A = 115 indium isotopes; Etude spectroscopique des noyaux au voisinage de la couche fermee Z = 50, au moyen des reactions ({sup 3}He, d) et (d, {sup 3}He) sur tous les isotopes pairs de l'etain, et de la reaction ({sup 3}He, d) sur les isotopes 113, 115 de l'indium

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-06-01

    A systematic study of ({sup 3}He, d) reactions at 18 MeV incident energy and (d, {sup 3}He) reactions at 22 MeV incident energy on {sup 112,114,116,118,120,122,124}Sn is presented. The distorted wave Born approximation (DWBA) is used to extract informations on (a) the transferred angular momentum l{sub p}, (b) the change of parity and (c) the spectroscopic factor. We have investigated the influence of the proton-neutron residual interaction on the spread of the pure proton configuration (particle or hole), and on the observed level sequence. Experimental results and predictions of the Kisslinger and Sorensen model are in reasonable agreement. A study of {sup 113,115}In ({sup 3}He, d) {sup 114,116}Sn reactions shows strong experimental evidence that the proton particle hole components are weak in the first excited states of tin nuclei. Furthermore, highly excited states ({approx} 4 to 6 MeV) having a simple structure with one predominant particle-hole configuration have been located. (authors) [French] Nous presentons une etude systematique des reactions ({sup 3}He, d) a 18 MeV et (d, {sup 3}He) a 22 MeV sur {sup 112,114,116,118,120,122,124}Sn. L'approximation des ondes deformees (DWBA) est utilisee pour obtenir des informations sur le moment angulaire transfere l{sub p}, sur le changement de parite et le facteur spectroscopique. Nous avons etudie l'influence de l'interaction residuelle proton-neutron sur la repartition de l'intensite a une seule particule ou trou de proton, et sur les sequences des niveaux observes. Les resultats experimentaux et les previsions theoriques du modele de Kisslinger et Sorensen sont en assez bon accord. L'etude des reactions {sup 113,115}In ({sup 3}He, d) {sup 114,116}Sn apporte la preuve experimentale que les composantes particule - trou de protons des premiers etats excites des noyaux residuels sont faibles. Elle permet aussi de localiser des niveaux a une energie d'excitation elevee ({approx} 4 a 6 MeV), ayant une structure simple a

  16. AU-EU “Strategic Partnership”

    DEFF Research Database (Denmark)

    Rodt, Annemarie Peen; Okeke, Jide

    2013-01-01

    This article appraises strategic partnership between the African Union (AU) and European Union (EU). It examines the context and nature of AU and EU security relations and explores the conditions under which partnership has a positive impact in this regard. This includes an evaluation...... of convergence between the two organizations and its effect or lack thereof on African security. The article concludes that events leading up to and initiatives following the 2007 Joint Africa–European Union Strategy have produced a degree of AU and EU convergence, which has had limited impact on the efficacy...... of the African security regime, the level of which remains mediocre at best....

  17. Information derived from French studies and achievements in the field of uranium isotope separation; Enseignements tires des etudes et realisations francaises relatives a la separation des isotopes de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    The work carried out in the field of uranium isotope separation, by gaseous diffusion and by ultracentrifugation, is reviewed. An economic estimate of the various parameters involved in the cost is given, and it is shown that only very large gaseous diffusion plants, corresponding to a programme of enriched uranium reactors of at least 4000 MWe to be installed yearly, can give an economically acceptable enriched uranium production. (authors) [French] La communication passe en revue les realisations effectuees dans le domaine de la separation des isotopes de l'uranium, par diffusion gazeuse et par ultracentrifugation. Elle donne une estimation economique des differents parametres intervenant dans les couts et met en evidence que seules les tres grandes usines de diffusion gazeuse, correspondant a un programme d'installation de reacteurs a uranium enrichi d'au moins 4000 MWe nouveaux par an, peuvent conduire a des productions d'uranium enrichi economiquement acceptables. (auteurs)

  18. Study of some properties of zirconium phosphate; Etude de quelques proprietes du phosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-05-01

    Zirconium phosphate has been studied with a view to using it as an ion exchanger: the first objective was to develop a method of preparation easy to apply and also reproducible. To this end, several tests were carried out varying the molar ratios of phosphorus and of zirconium. Some physical properties such as the diffraction of X-rays were examined. The work then involved certain chemical properties, particularly the percentages of free water and structural water given by the loss on calcination, the Karl-Fisher method and the weight losses by thermogravimetry. Finally an attempts was made to apply the exchanger to the separation of alkaline ions. The static tests showed that the order of fixation of these ions was Cs{sup +} > Rb{sup +} >> K{sup +} > Na{sup +}. Tests with columns showed that Na{sup +} and K{sup +} were easily separable, as was the Rb{sup +}-Cs{sup +} mixture, this last pair being fairly difficult to dissociate. (author) [French] Le phosphate de zirconium a ete etudie en vue de son utilisation comme echangeur d'ions: le premier but a atteindre a ete de mettre au point une preparation pouvant se reveler facilement utilisable ainsi qu'aisement reproductible. A cet effet, plusieurs essais ont ete effectues en faisant varier les rapports molaires du phosphore et du zirconium. Quelques proprietes physiques, telle la diffraction des rayons X, ont ete abordees. Ensuite, l'etude a porte sur certaines proprietes chimiques, particulierement les pourcentages d'eau libre et d'eau de structure par des pertes au feu, utilisation de la methode de Karl-Fisher, ainsi que des pertes de poids a la thenmobalance. Enfin, on a tente d'utiliser l'echangeur a la separation des ions alcalins. Les etudes statiques ont permis de constater que l'ordre de fixation de ces ions etait Cs{sup +} > Rb{sup +} >> K{sup +} > Na{sup +}. Les essais effectues en colonne ont montre que Na{sup +} et K{sup +} etaient aisement separables entre eux, ainsi que du couple Rb{sup +}-Cs{sup +}, ce

  19. The study of neutron transport by oscillation method; Etude du transport des neutrons par la methode de modulation

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V

    1959-07-01

    The oscillation method is of very general use for studying the behavior of thermal neutrons in media. The main experiments are described and a general theory of them is given. This theory, which is presented in the first part, is established using the two-group approximation which has proved its efficiency in the case of thermal neutron piles. The validity of the two-group approximation is recalled. This allows definition of the meaning of the parameters used in the theory and which are measured in these experiments. The experiments carried out by this method are described, especially those performed at the Centre d'Etudes Nucleaires de Saclay where the method has been extensively used. These experiments are interpreted by means of the general theory given previously. In this way, the identity of parameters measured by this method and those given by the theory is proved. This is particularly conclusive is the case of the mean life of neutrons in a pile. (author) [French] La methode de modulation est un procede tres general d'etude des proprietes neutroniques des milieux contenant des neutrons thermiques. Le present rapport a pour but de decrire les principales de ces experiences et d'en donner une theorie generale. Cette theorie, exposee dans la premiere partie, est etablie dons le cadre de l'approximation a deux groupes de vitesse qui a prouve son efficacite dons le cas des piles a neutrons thermiques. Le domaine de validite de l'approximation a deux groupes est rappele au debut, ce qui permet de definir avec precision la signification des parametres qui entrent dons la theorie et qui font l'objet de ces mesures. La deuxieme partie decrit les experiences realisees, en particulier celles effectuees au Centre d'Etudes Nucleaires de Saclay ou la methode a ete considerablement developpee. Ces experiences sont interpretees dans le cadre de la theorie generale exposee precedemment. On prouve ainsi l'identite des parametres mesures par cette methode et de ceux figurant

  20. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    C'est donc dans le cadre de la modélisation du climat régional que ... Les cartes ont été réalisées grâce au logiciel de cartographie Ferret version 6.0 élaboré par le ... reanalyse météorologique utilisées comme conditions initiales au modèle.

  1. Study of uranium-titanium diffusion; Etude de la diffusion uranium-titane

    Energy Technology Data Exchange (ETDEWEB)

    Adda, Y; Philibert, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)

    1959-07-01

    . (author) [French] Dans le cadre de recherches sur la diffusion chimique de l'uranium et des metaux de transition, nous avons etudie le systeme uranium-titane. Les couples de diffusion sont prepares, suivant une technique que avons deja decrite, par soudage sous pression de plaquettes d'uranium et de titane. Apres traitement de diffusion sous vide, les echantillons sont etudies micrographiquement suivant une section polie. Cet examen nous a permis de mettre en evidence une diffusion intergranulaire au-dessous de 650 deg. C; aux temperatures superieures, la diffusion a lieu uniquement en volume, et la zone de diffusion apparait alors comme une succession de bandes qui se distinguent par leur aspect micrographique. L'etude de la cinetique de croissance de ces bandes nous a permis de mesurer les 'coefficients de penetration' correspondants. En outre, nous avons observe, dans la zone de diffusion, des variations importantes de microdurete, que nous avons cherche a relier a la variation de concentration. Celle-ci est mesuree par analyse ponctuelle au moyen de la microsonde de Castaing. Nous avons ainsi etabli avec precision les courbes concentration-penetration pour des temperatures comprises entre 950 et 1075 deg. C. A partir de ces courbes nous avons calcule le coefficient de diffusion D en fonction de la concentration c par la methode de Matano. La coube D(c) presente a toutes les temperatures une forme en U, deja observee pour le systeme U-Zr. L'energie d'activation passe par un maximum de 42 kcal/g pour une concentration atomique 0,5. Bien que nous n'ayons observe que rarement la presence de pores dans la zone de diffusion, nous avons neanmoins observe un effet Kirkendall important en etudiant les deplacements x{sub i} d'un interface repere au moyen de fils de tungstene. Ces deplacements peuvent s'exprimer en fonction du temps t et de la temperature T par la relation x{sub i} = 0,9 t {sup 1/2} exp ( - 14600/(RT)). Enfin, au moyen des equations de Darken nous avons calcule

  2. Wear studies in the shearing process by means of irradiated tools; Etudes d'usure dans les operations de cisaillement, au moyen d'outils irradies; Issledovaniya problemy iznosa v protsesse skalyvaniya posredstvom obluchennykh instrumentov; Estudios de desgaste en las operaciones de cizallamiento, realizados con ayuda de herramientas irradiadas

    Energy Technology Data Exchange (ETDEWEB)

    Sata, Toshio; Abe, Kunio; Nakajima, Kiyoshi [Institute of Physical and Chemical Research, Komagome, Bunkyo-Ku, Tokyo (Japan)

    1962-01-15

    pastilles, tandis que la radioactivite des trous variait a peine. Cela montre que l'usure de la matrice peut etre mesuree d'apres la radioactivite des pastilles, et celle du poincon d'apres la radioactivite des trous. On a eu recours a cette methode pour suivre le processus d'usure du poincon et de la matrice en employant differents lubrifiants et differentes toles, ce qui a permis de faire les constatations suivantes: 1. Au debut du poinconnage, le taux d'usure du poincon et celui de la matrice sont tres eleves mais diminuent rapidement, pour devenir finalement stationnaires apres decoupage d'environ 4 a 500 pieces. 2. L'usure du poincon est d'environ 20 % plus forte que celle de la matrice. 3. Les lubrifiants contenant des additifs qui resistent aux pressions extremes, tels que le chlore, le phosphore ou le soufre, reduisent l'usure des outils, tandis que les huiles minerales raffinees n'apportent guere d'amelioration. 4. La plus forte usure des outils se produit lors du poinconnage des toles les plus dures. Cette usure est environ trois fois plus forte pour l'acier inoxydable et environ six fois plus forte pour l'acier riche en silicium que pour l'acier pauvre en carbone. (author) [Spanish] Se ha estudiado el desgaste de las herramientas utilizadas en el corte de laminas metalicas con punzones y matrices de acero rapido irradiados en un reactor. Se recortaron a punzon discos de 10 mm de diametro en laminas de acero pobre en carbono, acero inoxidable y acero al silicio de 0,5 mm de espesor en estado seco y lubricado. Despues del punzonamiento, se midio la radiactividad de los discos y de los orificios. Al reemplazar la matriz radiactiva por otra no irradiada, se detecto escasa actividad en los discos, mientras que la radiactividad de los orificios apenas sufrio variacion. Ello demuestra que el desgaste de la matriz y del punzon pueden medirse en funcion de la radiactividad de los discos y de los orificios, respectivamente. Con ayuda de este metodo, se estudio el desgaste

  3. Securite fonciere et gestion de la fertilite des sols: etudes de cas au Ghana et au Benin.

    NARCIS (Netherlands)

    Saidou, A.; Adjei-Nsiah, S.; Kossou, D.; Sakyi-Dawson, O.; Kuyper, T.W.

    2007-01-01

    Dans le cadre d¿un programme interuniversitaire de recherche, Convergence des Sciences (CoS), une étude a été conduite sur les stratégies de gestion de la fertilité du sol dans les régions centrales du Ghana (Wenchi) et du Bénin (Savè) où des pratiques variables de gestion de la fertilité du sol

  4. Analyse de régression quantile de la relation entre la langue et l’intervalle entre les grossesses au Québec (Canada

    Directory of Open Access Journals (Sweden)

    Nathalie Auger

    2018-01-01

    Full Text Available Introduction. On sait que les intervalles courts comme les intervalles longs entre les grossesses sont associés à des issues périnatales défavorables, comme des fausses couches et des accouchements prématurés, mais les différences culturelles à ce sujet sont mal connues. Repérer les inégalités culturelles dans les intervalles entre les grossesses est nécessaire afin d'améliorer les résultats relatifs à la santé de la mère et de l’enfant. Nous avons ainsi évalué les intervalles entre les grossesses chez les anglophones et les francophones du Québec. Méthodologie. Nous avons obtenu les dossiers de naissance de tous les enfants nés au Québec entre 1989 et 2011. Nous avons recensé 571 461 femmes ayant eu au moins deux naissances et déterminé l’intervalle entre leurs grossesses. Les intervalles courts entre les grossesses (moins de 18 mois ont été définis comme étant le 20e percentile de la distribution, et les intervalles longs (60 mois ou plus, comme le 80e percentile. À l’aide de régressions quantiles, nous avons évalué l’association entre la langue et les intervalles courts et longs, ajustés en fonction des caractéristiques de la mère. Nous avons évalué les différences au fil du temps et selon l’âge de la mère pour les groupes défavorisés, qui ont été définis par l’absence de diplôme d’études secondaires, la résidence en milieu rural et le fait de vivre dans un quartier défavorisé matériellement. Résultats. Dans les modèles de régression ajustés, les anglophones sans diplôme d’études secondaires avaient des intervalles plus courts de 1,0 mois (intervalle de confiance [IC] à 95 % : −1,5 à −0,4 par rapport à leurs homologues francophones au 20e percentile de la distribution et plus longs de 1,9 mois (−0,5 à 4,3 au 80e percentile. Les résultats étaient similaires pour les anglophones des régions rurales et des quartiers matériellement défavorisés. Les

  5. Risk analysis related to dangerous materials transport and storage in urban areas; L'integration du risque lie au transport et au stockage des produits chimiques dans la planification urbaine: l'apport des outils d'analyse decisionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Lombard, J; Hubert, P; Pages, P

    1989-12-01

    determiner sur des bases objectives quel moyen retenir. Cette etape n'est pas pour autant suffisante, car l'integration des resultats dans les processus decisionnels reste a organiser. L'objet de ce rapport est de presenter differentes methodes d'aide a la decision utilisables a ce jour, en soulignant les criteres sur lesquels elles fondent leur comparaison et leurs limitations dans le contexte envisage ici. Quoique ce point necessite une analyse plus approfondie, quelques rappels generaux des principales particularites de la gestion des risques en milieu urbain (implication possible de multiples acteurs dans la prise de decision et/ou de differents criteres de choix; difficulte d'evaluation des impacts) sont effectues. Les principales methodes d'aide a la decision sont ensuite presentees. Ces methodes se fondent sur un critere unique (respect d'une contrainte reglementaire), sur quelques criteres monetarisables (cout-benefice) ou sur de multiples criteres de choix (fonctions d'utilite). Ces methodes assez generales doivent faire l'objet d'adaptations speifiques pour pouvoir etre appliquees au mieux a un domaine particulier. Pour ce qui concerne la gestion des risques accidentels, les adaptations suivantes sont presentees de maniere critique : - Notion de limite de risque maximal individuel (generalisation d'une contrainte reglementaire). - Adoption de differentes valeurs de la vie humaine en fonction de la nature des consequences de l'accident (generalisation de la methode cout-benefice). - Utilisation de facteurs d'aversion pour le risque (application de la theorie de l'utilite pour prendre en compte le poids important accorde aux evenements catastrophiques). Ces differents developpements visent a proposer des versions des outils d'analyse decisionnelle qui s'appliquent efficacement a la gestion du risque en milieu urbain. (author)

  6. PENULISAN ETUDE-ETUDE MUSIK TALEMPONG UNGGAN (Sebuah Usaha Pembelajaran Musik Tradisi Berbasis Literatur

    Directory of Open Access Journals (Sweden)

    Asri MK

    2014-12-01

    Full Text Available “Talempong unggan”, a traditional music from Minangkabau community particularly in Unggan, Sumpur Kudus, Sijunjung Regency, West Sumatera Indonesia is classified into genre of “talempong duduak” (rea. Due to its special musical concept and the playing technics, this traditional music is selected as a practising course in the Karawitan Department of Indonesian Institute of Art (ISI Padang Panjang since 1993 till now. In a system of class learning with many students, Talempong Unggan definitely needs supporting methods and learning technics suitable for the course where the students can reach their maximum skills. All the melody of “talempong unggan” that has been made as a material of practice is transcribed to the system of numeric notation and rhythm motive of “gendang” and “aguang” which is written into signs and special notation. All of qualitative data is formulated into finding methods, technics and etude of learning ensamble of Talempong Unggan the traditional music that learned in Karawitan Department of ISI Padang Panjang. Key words: Talempong Unggan, Methods, Technics, Etude

  7. Reconstruction de la surface de Fermi dans l'etat normal d'un supraconducteur a haute Tc: Une etude du transport electrique en champ magnetique intense

    Science.gov (United States)

    Le Boeuf, David

    Des mesures de resistance longitudinale et de resistance de Hall en champ magnetique intense transverse (perpendiculaire aux plans CuO2) ont ete effectuees au sein de monocristaux de YBa2Cu3Oy (YBCO) demacles, ordonnes et de grande purete, afin d'etudier l'etat fondamental des supraconducteurs a haute Tc dans le regime sous-dope. Cette etude a ete realisee en fonction du dopage et de l'orientation du courant d'excitation J par rapport a l'axe orthorhombique b de la structure cristalline. Les mesures en champ magnetique intense revelent par suppression de la supraconductivite des oscillations magnetiques des resistances longitudinale et de Hall dans YBa2Cu 3O6.51 et YBa2Cu4O8. La conformite du comportement de ces oscillations quantiques au formalisme de Lifshitz-Kosevich, apporte la preuve de l'existence d'une surface de Fermi fermee a caractere quasi-2D, abritant des quasiparticules coherentes respectant la statistique de Fermi-Dirac, dans la phase pseudogap d'YBCO. La faible frequence des oscillations quantiques, combinee avec l'etude de la partie monotone de la resistance de Hall en fonction de la temperature indique que la surface de Fermi d'YBCO sous-dope comprend une petite poche de Fermi occupee par des porteurs de charge negative. Cette particularite de la surface de Fermi dans le regime sous-dope incompatible avec les calculs de structure de bande est en fort contraste avec la structure electronique presente dans le regime surdope. Cette observation implique ainsi l'existence d'un point critique quantique dans le diagramme de phase d'YBCO, au voisinage duquel la surface de Fermi doit subir une reconstruction induite par l'etablissement d'une brisure de la symetrie de translation du reseau cristallin sous-jacent. Enfin, l'etude en fonction du dopage de la resistance de Hall et de la resistance longitudinale en champ magnetique intense suggere qu'un ordre du type onde de densite (DW) est responsable de la reconstruction de la surface de Fermi. L'analogie de

  8. Study of the low energy gamma transitions of molybdenum 99; Etude des transitions gamma de basse energie du molybdene 99

    Energy Technology Data Exchange (ETDEWEB)

    Ravier, J.

    1959-07-01

    The study of the decay scheme of Mo{sup 99} has been performed on the magnetic iron-less and double focalization spectrograph of the Institute of Nuclear Physics of Lyon. Methods of internal and external conversion have been used. The intensities of the Mo{sup 99} sources used were not strong enough to determine the characteristics of the internal conversion accurately but were sufficient to precise the decay scheme at low energy. We have determined the internal conversion ratio for the transition of 180 KeV, we have got: 0.13 ± 0.03 which is not in agreement with the value given by a previous experiment based on γ-γ coincidence. Our method seems to be more reliable. We confirm the E2 feature of this transition and its 5/2+ spin. We have determined another important parameter for the 180 KeV de-excitation: the percentage of transitions that do not pass by the isomeric level but by the 140 KeV level is (6 ± 2)%, the isomeric level being at 142 KeV. The gamma spectra at low energy has been studied through the photoelectric effect in a lead converter [French] L'etude du schema de desintegration du Mo{sup 99} deja faite par differents auteurs a ete reprise par des methodes de conversion interne et externe, an moyen du spectrographe magnetique sans fer et a double focalisation de l'Institut de Physique Nucleaire de Lyon. Apres avoir cherche les possibilites d'obtention de sources de haute activite specifique par separation isotopique Szilard-Chalmers sur des molybdates alcalins, le spectre de conversion interne a basse energie a ete mesure. Ainsi se trouverent etre determines les coefficients partiaux de conversion interne. Le spectre γ a basse energie a ete etudier au moyen de l'effet photoelectrique sur un convertisseur de plomb. Les coefficients de conversion interne et les intensites relatives des differentes transitions ont ete calcules moyennant certaines hypotheses. La comparaison entre les valeurs donnees par la theorie et l'experience des differentes

  9. Development of a slow mono-kinetic electron source; Etude et realisation d'une source d'electrons lents monocinetiques

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-06-01

    A comparative study of already existing slow mono-kinetic electron guns shows that those using a 127 degrees electrostatic selector can be improved still further to arrive at the performances obtained with spherical 180 degrees selectors for example. For this reason we have examined the 127 degrees selector theoretically in more detail; it appears that it should be possible to obtain a resolving power better than 30 mV for a current of about 10{sup -10} A, on condition that certain improvements be made to the instrument as normally designed, in particular concerning the entrance and exit slides. As a result, the usual suppressors for the scattered electrons are no longer necessary. The development of this apparatus has been carried out with particular care: the dimensional characteristics are fixed to an accuracy of a few microns, although the instrument can be baked out at 300 C. The experimental results are in excellent agreement with the theoretical predictions: for a current of 10{sup -10} A, the measured resolving power is 24 {+-} 4 mV. The easy detection of the He{sup -} resonance line at 19.3 eV has confirmed the advantages of this apparatus for the study of atomic collisions. (author) [French] L'etude comparative des canons a electrons lents monocinetiques realises jusqu'a present montre que ceux qui utilisent un selecteur electrostatique a 127 degres peuvent etre encore perfectionnes en vue de parvenir aux performances obtenues avec les selecteurs spheriques a 180 degres par exemple. D'ou notre etude theorique approfondie du selecteur a 127 degres qui nous a conduit a esperer une resolution meilleure que 30 mV pour un courant de l'ordre de 10{sup -10} A a condition d'apporter certaines ameliorations a la conception usuelle de cet instrument notamment au niveau des fentes d'entree et de sortie. Par voie de consequence les suppresseurs habituels d'electrons parasites deviennent inutiles. L'etude et la mise au point de l'appareil ont fait l'objet de soins

  10. Comparison Of The Worth Of Critical And Exponential Measurements For Heavy-Water-Moderated Reactors; Valeur Relative des Mesures Critiques et Exponentielles pour l'Etude des Reacteurs Ralentis a l'Eau Lourde; Sravnenie tsennosti kriticheskikh i ehksponentsial'nykh izmerenij dlya reaktorov s tyazhelovodnym zamedlitelem; Valor Relativo de las Mediciones Criticas y Exponenciales para los Reactores Moderados por Agua Pesada

    Energy Technology Data Exchange (ETDEWEB)

    Graves, W. E.; Hennelly, E. J. [Savannah River Laboratory, E.I. Du Pont De Nemours and Co., Aiken, SC (United States)

    1964-02-15

    experiences a l'aide d'ensembles critiques et les comparaisons faites entre experiences exponentielles et experiences critiques font l'objet d'un apercu dans le present memoire et d'un expose detaille dans un autre memoire. 3. Evaluation des barres de controle Une analyse appropriee des experiences exponentielles semble donner de bons resultats lorsqu'il s'agit de mesures de l'antireactivite totale. Cependant, si l'on veut etudier convenablement certaines caracteristiques du flux, il faut un ensemble critique de dimensions normales tel que le PDP. 4. Coefficients de temperature Les experiences exponentielles offrent une methode excellente si l'on veut determiner le coefficient thermique du laplacien pour un chauffage de reseau uniforme. Une installation speciale (PSE) du SRL permet de proceder a ces mesures a des temperatures allant jusqu'a 215 Degree-Sign C. Pour un chauffage non uniforme, on prefere generalement utiliser des ensembles critiques. 5. Reseaux mixtes Dans les reacteurs, on utilise rarement les reseaux uniformes simples auxquels les experiences exponentielles s'appliquent essentiellement. Au SRL, on fait des experiences critiques a chargements mixtes tant pour mesurer les effets directs dans des maquettes de reacteurs que pour verifier les calculs de diffusion heterogenes et a deux dimensions. 6. Etudes,au point de vue de l'etat critique, du comportement dans l'eau ordinaire d'un combustible destine a un reseau a eau lourde Les ensembles exponentiels du SRL se sont reveles particulierement utiles pour les etudes visant a determiner comment manipuler le combustible enrichi dans l'eau ordinaire. Ces travaux ne necessitent pas une tres grande exactitude; les experiences exponentielles d'un caractere, plus general sont nettement preferables aux experiences critiques d'un caractere plus particulier. (author) [Spanish] Con los conjuntos criticos y los exponenciales se obtienen generalmente informaciones en parte repetidas sobre los reticulados de reactor. En los

  11. La circulation des déchets au sein de l’Union européenne. Etude des rapports entre le régime mis en place par le Titre II du Règlement n°1013/2006 et la circulation des marchandises.

    OpenAIRE

    Krack, Noémie

    2017-01-01

    La gestion des déchets n’a pas toujours été une priorité pour nos sociétés, et ce même si les Romains et les Grecs faisaient figure de précurseurs. Les découvertes scientifiques relatives aux épidémies de grandes ampleurs, telle la peste noire, démontrèrent l’importance d’un traitement correct des déchets. En effet, leur abandon et leur accumulation sont responsables de la prolifération de germes et microbes pathogènes. Or il faut savoir qu’à l’époque les cités occidentales étaient malsaines ...

  12. Photoswitchable Faraday effect in EuS-Au nanosystems

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Akira; Nakanishi, Takayuki; Kitagawa, Yuichi; Fushimi, Koji; Hasegawa, Yasuchika [Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, North-13 West-8, Kita-ku, 060-8628, Sapporo (Japan)

    2016-01-15

    Effective photoswitchable europium sulfide nanocrystals with gold nanoparticles using dithiol (DDT: 1,10-decanedithiol) joint molecules, EuS-Au nanosystems, are demonstrated. The TEM image indicates the formation of EuS-Au nanosystems composed of cube-shaped EuS nanocrystals and spherical Au nanoparticles. Under visible-light irradiation, a drastic change of absorption band of EuS-Au nanosystems at around 600 nm was observed. The Faraday effects of EuS-Au nanosystems were estimated using magnetic circular dichroism (MCD) measurements. The effective change of the MCD spectra of EuS-Au nanosystems under visible-light irradiation was successfully observed at around 670 nm for the first time. The effective reversible changes in MCD spectra with the alternative irradiation cycles of visible light (>440 nm) and dark are also presented. The decrease rate of rotation angle at 670 nm of EuS-Au nanosystems is larger than that of absorbance. These results indicate that the effective change of MCD spectra of EuS-Au nanosystems would be dominated not only by a drastic change of absorption band related to enhanced LSPR of Au nanoparticles but also by specific interaction between EuS and Au in nanosystem under irradiation. Illustration of photoswitch and TEM image of EuS-Au nanosystems. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Main results obtained in France in the development of the gaseous diffusion process for uranium isotope separation; Principaux resultats obtenus en France dans les etudes sur la separation des isotopes de l'uranium par diffusion gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Frejacques, C; Bilous, O; Dixmier, J; Massignon, D; Plurien, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The main problems which occur in the study of uranium isotope separation by the gaseous diffusion process, concern the development of the porous barrier, the corrosive nature of uranium hexafluoride and also the chemical engineering problems related to process design and the choice of best plant and stage characteristics. Porous barriers may be obtained by chemical attack of non porous media or by agglomeration of very fine powders. Examples of these two types of barriers are given. A whole set of measurement techniques were developed for barrier structure studies, to provide control and guidance of barrier production methods. Uranium hexafluoride reactivity and corrosive properties are the source of many difficult technological problems. A high degree of plant leak tightness must be achieved. This necessity creates a special problem in compressor bearing design. Barrier lifetime is affected by the corrosive properties of the gas, which may lead to a change of barrier structure with time. Barrier hexafluoride permeability measurements have helped to make a systematic study of this point. Finally an example of a plant flowsheet, showing stage types and arrangements and based on a minimisation of enriched product costs is also given as an illustration of some of the chemical engineering problems present. (author) [French] Les principaux problemes qui se sont poses dans l'etude de la separation des isotopes de l'uranium par diffusion gazeuse, sont ceux relatifs a l'obtention de barrieres poreuses, ceux lies a l'utilisation de l'hexafluorure d'uranium, enfin les problemes de genie chimique relatifs au procede et a l'agencement optimum des etages et des cascades entre elles. On peut obtenir des barrieres poreuses soit par attaque de membranes pleines, soit par agglomeration de poudres de petites dimensions. Des exemples de ces deux types de barrieres seront donnes. L'etude des proprietes de texture des barrieres obtenues, necessaire pour orienter les recherches de

  14. Study and analysis of failure modes of the electrolytic capacitors and thyristors, applied to the protection system of the LHC (Large Hadron Collider); Etude et analyse des modes de defaillances des condensateurs electrolytiques a l'aluminium et des thyristors: appliquees au systeme de protection du LHC (Large Hadron Collider)

    Energy Technology Data Exchange (ETDEWEB)

    Perisse, F

    2003-07-15

    The study presented in this thesis is a contribution about the analysis of failures modes of electrolytic capacitors and thyristors. The studied components are main elements of the protection system of the superconductive magnets of the LHC. The study of the ageing of the electrolytic capacitors has shown that their reliability is strongly related to their technological characteristic. Evolution of their principal indicator of ageing (ESR) can be modeled according to different laws chosen according to their running mode. It appears that the prediction of failure of these components other than that due to wear can be only statistical taking into account the many causes of failure involving various modes of failure. In order to be able to evaluate influence of the ageing of the electrolytic capacitors on a system, simple models taking into account this parameters as well as the effective temperature of the component are proposed. An acceptable precision taking into account the simplicity of the models is obtained. The study of the thyristors has shown that these components have little drift of parameters in static ageing, on the other hand of many failures by short-circuit were observed. These failures always have a local origin, and are due to defects of the components. The breakdown voltage strongly depends on the quality of the thyristor as well as the technology employed. (author)

  15. Study of ultrasonic non destructive testing methods adapted to the sizing and the characterization of defects located in low thickness materials: analysis of the corner effect; Etude de methodes ultrasonores adaptees au dimensionnement et a la caracterisation des defauts dans des structures de faibles epaisseurs: analyse de l`effet de coin

    Energy Technology Data Exchange (ETDEWEB)

    Roy, O.

    1994-12-14

    This work is devoted to the enhancement of non destructive testing using ultrasound. It concerns especially the inspection of steam generator tubes located in water pressure reactors. The study motivation is the sizing of defects such as surface breaking cracks. Because of the low thickness of tubes, at least two corner echoes result from an inspection: one comes from the reflection of the ultrasonic beam on the defect and on the inner surface, the other comes from the reflection on the defect and on the outer surface. In order to size the defect, we consider the corner echo related to the surface opposite to the defect. We present experimental results showing that this corner echo depends on the position and the size of the defect. Then we carry out a theoretical model in order to predict the corner effect echographic response. A simplified version of that model only considers the amplitude distribution in the ultrasonic beam. It allows to calculate the amplitude recorded by the transducer during its displacement, for different sizes of defect. The echo-dynamic curves we obtain are quite representative of the experimental curves. We explain how to size the ligament by minimizing the difference between experiment and simulation. A second version of the model is based on the impulse response formalism. It allows to understand and to predict changes on waveforms resulting from corner effect for different positions of the transducer. (Author). 41 refs., 76 figs., 8 tabs.

  16. Study of the hydrogen behavior in amorphous hydrogenated materials of type a - C:H and a - SiC:H facing fusion reactor plasma; Etude du comportament de l`hydrogene dans des materiaux amorphes hydrogenes de type a - C:H et a - SiC:H devant faire face au plasma des reacteurs a fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barbier, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire

    1997-04-10

    Plasma facing components of controlled fusion test devices (tokamaks) are submitted to several constraints (irradiation, high temperatures). The erosion (physical sputtering and chemical erosion) and the hydrogen recycling (retention and desorption) of these materials influence many plasma parameters and thus affect drastically the tokamak running. First, we will describe the different plasma-material interactions. It will be pointed out, how erosion and hydrogen recycling are strongly related to both chemical and physical properties of the material. In order to reduce these interactions, we have selected two amorphous hydrogenated materials (a-C:H and a-SiC:H), which are known for their good thermal and chemical qualities. Some samples have been then implanted with lithium ions at different fluences. Our materials have been then irradiated with deuterium ions at low energy. From our results, it is shown that both the lithium implantation and the use of an a - SiC:H substrate can be beneficial in enhancing the hydrogen retention. These results were completed with thermal desorption studies of these materials. It was evidenced that the hydrogen fixation was more efficient in a-SiC:H than in a-C:H substrate. Results in good agreement with those described above have been obtained by exposing a - C:H and a - SiC:H samples to the scrape off layer of the tokamak of Varennes (TdeV, Canada). A modelling of hydrogen diffusion under irradiation has been also proposed. (author) 176 refs.

  17. Etude de la densité de particules chargées et des mésons vecteurs de basses masses en collisions Pb-Pb à sqrt(s)NN = 2.76 TeV dans ALICE au LHC

    CERN Document Server

    Guilbaud, M.

    The matter is composed of hadrons of which quarks and gluons are the elementary components. These do not exist in a free state in ordinary matter and are therefore permanently confined in hadrons. However, according to theoretical predictions, a few microseconds after the Big Bang, the temperature was high enough to create a deconfined state of quarks and hadrons : the Quark and Gluon Plasma (QGP). The Large Hadron Collider (LHC) at CERN (Geneva) is a particle accelerator which accelerates, among others, ions and produces collisions with energies per nucleons in the center of mass up to several TeraelectronVolts. It is thus possible to achieve temperatures to recreate the QGP phase to study its properties. The experiment ALICE (A Large Ion Collider Experiment) is dedicated to the study of such ultra-relativistic heavy-ion collisions. The lifetime of the QGP being too low, it is not possible to study it directly. It is then necessary to use indirect observables. This PhD work is directly related to the study o...

  18. Study and analysis of failure modes of the electrolytic capacitors and thyristors, applied to the protection system of the LHC (Large Hadron Collider); Etude et analyse des modes de defaillances des condensateurs electrolytiques a l'aluminium et des thyristors: appliquees au systeme de protection du LHC (Large Hadron Collider)

    Energy Technology Data Exchange (ETDEWEB)

    Perisse, F

    2003-07-15

    The study presented in this thesis is a contribution about the analysis of failures modes of electrolytic capacitors and thyristors. The studied components are main elements of the protection system of the superconductive magnets of the LHC. The study of the ageing of the electrolytic capacitors has shown that their reliability is strongly related to their technological characteristic. Evolution of their principal indicator of ageing (ESR) can be modeled according to different laws chosen according to their running mode. It appears that the prediction of failure of these components other than that due to wear can be only statistical taking into account the many causes of failure involving various modes of failure. In order to be able to evaluate influence of the ageing of the electrolytic capacitors on a system, simple models taking into account this parameters as well as the effective temperature of the component are proposed. An acceptable precision taking into account the simplicity of the models is obtained. The study of the thyristors has shown that these components have little drift of parameters in static ageing, on the other hand of many failures by short-circuit were observed. These failures always have a local origin, and are due to defects of the components. The breakdown voltage strongly depends on the quality of the thyristor as well as the technology employed. (author)

  19. Theoretical and experimental study of high strain, high strain rate materials viscoplastic behaviour. Application to Mars 190 steel and tantalum; Etude theorique et experimentale du comportement viscoplastique des materiaux aux grandes deformations et grandes vitesses de deformations. Application a l'acier mars 190 et au tantale

    Energy Technology Data Exchange (ETDEWEB)

    Juanicotena, A

    1998-07-01

    This work enters in the general framework of the study and modelling of metallic materials viscoplastic behaviour in the area of high strain and high strain rate, from 10{sup 4} to 10{sup 5} s{sup -1}. We define a methodology allowing to describe the behaviour of armor steel Mars 190 and tantalum in the initial area. In a first time, the study of visco-plasticity physical mechanisms shows the necessity to take into account some fundamental processes of the plastic deformation. Then, the examination of various constitutive relations allows to select the Preston-Tonks-Wallace model, that notably reproduce the physical phenomenon of the flow stress saturation. In a second part, a mechanical characterization integrating loading direction, strain rate and temperature effects is conducted on the two materials. Moreover, these experimental results allow to calculate associated constants to Preston-Tonks-Wallace, Zerilli-Armstrong and Johnson-Cook models for each material. In a third time, in order to evaluate and to validate these constitutive laws, we conceive and develop an experimental device open to reach the area of study: the expanding spherical shell test. It concerns to impose a free radial expanding to a thin spherical shell by means a shock wave generated by an explosive. By the radial expanding velocity measure, we can determine stress, strain rate and strain applied on the spherical shell at each time. In a four and last part, we evaluate constitutive models out of their optimization area's. This validation is undertaken by comparisons 'experimental results/calculations' with the help of global experiences like expanding spherical shell test and Taylor test. (author)

  20. Study of the production of {phi}, {rho}, {omega} mesons in the ultra-relativistic heavy ion collisions at the SPS of CERN; Etude de la production des mesons {phi}, {rho} et {omega} dans les collisions d'ions lourds ultra-relativistes au SPS du CERN (dans l'experience NA50)

    Energy Technology Data Exchange (ETDEWEB)

    Villatte, L

    2001-03-28

    The NA50 experiment is one of the experiment using the SPS (Super Proton Synchrotron) beam at CERN (european laboratory for particle physics). One of the common aim of the SPS experiment is to look for the existence of a new state of the nuclear matter: the quark-gluon plasma. Among the proposed signatures of the quark-gluon plasma is the enhanced production of particles containing strange quarks. In the current work, the NA50/NA38 experiment data are analysed and the relative production of the {phi} and {rho} + {omega} mesons are obtained from Pb-Pb collisions at 158 and S-U at 200 GeV per nucleon. The measured ({phi}/({rho} +{omega})){mu}{mu} ratio as a function of the transverse mass does not present any unexpected behavior, however, central collisions as compared to peripheral collisions show an increase by a factor 1.7. The {phi} and {rho}+{omega} multiplicities are extracted for the Pb-Pb collisions and show that the enhancement of the ({phi}/({rho}+{omega})){mu}{mu} ratio is due to the {phi} meson production increase. The evolution of the {phi} meson multiplicity, versus the number of participant nucleus (N{sub part}), is different from that of the multi-strange baryons. The effective temperatures are deduced from the study of the {phi} and {rho} + {omega} production cross sections with respect to the transverse mass and compared to those obtained by other experiments and other particles. An additional study is done to extract the K/{pi} ratio versus N{sub part}. (authors)

  1. Optimisation of the muon spectrometer from the detector ALICE used for the study of the quark and gluon plasma at LHC; Optimisation du spectrometre a muons du detecteur ALICE pour l'etude du plasma de quarks et de gluons au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Guernane, R

    2001-01-01

    The ALICE experiment performed at the LHC will establish and study the phase transition from hadronic matter to a matter to a state of deconfined partons called Quark Gluon Plasma (QGP). The suppression of heavy flavour resonances (J{phi},{gamma}) is the most promising probe for diagnosing the formation and early stages of the QGP in ultrarelativistic heavy ion collisions. The complete spectrum of heavy quarkonia resonances, i.e. J/{phi}, {phi}', {gamma}, {gamma}' and {phi}' will be measured via their muonic decay in a forward spectrometer with a mass resolution sufficient to separate all states. It is composed of five tracking stations, each consisting of two Cathode Pad Chambers (CPC). In this work, we developed a prototype of CPC having the original feature of parallel charge read out from one segmented cathode. The geometry and operating parameters have been optimized for station 3. The expected multi-hit rate and multi-hit deconvolution have been evaluated with a complete detailed simulation and an efficient method to disentangle close hits has been proposed. The magnetic field effect on the intrinsic spatial resolution of the chambers has also been estimated. The simulated performance of the CPC's is confirmed by beam-test results obtained at CERN with prototypes. The measurement of dimuons is expected to be contaminated by beam-related background. The rate of beam-gas interactions is several orders of magnitude larger than the signal rate for p-p collisions which is the reference for further studies of p-A and A-A collisions. The ALICE Collaboration decided to equip the muon spectrometer with a level 0 trigger counter (V0) in order to validate the dimuon trigger signal in p-p mode. The various steps involved in designing the V0 scintillator hodoscope are presented in this thesis. (author)

  2. Contribution to the Chemical and Technological Study of Ammonium Diuranate Precipitation; Contribution a l'etude chimique et technologique de la precipitation de diuranate d'ammonium

    Energy Technology Data Exchange (ETDEWEB)

    Vuillemey, R [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-07-01

    The present work is designed to study the relationship between the conditions for precipitation by ammonia and the properties of ammonium diuranate obtained either from uranyl nitrate solution or from gaseous uranium hexafluoride. In each case the optimum processes are defined leading on the one hand to uranate which can afterwards be treated in a reduction- fluorination oven to give uranium tetrafluoride, and on the other hand to a uranate suitable for the production of a sinterable uranium oxide. In particular it is shown that the treatment of uranyl nitrate solutions by stoichiometric quantities of ammonia leads to the complete precipitation of the uranium leaving less than 1 mg/litre of uranium in the solution, whereas the treatment of uranium hexafluoride necessitates the use of at least 8 times the stoichiometric quantity. (author) [French] Le present travail a pour objet l'etude des relations entre les conditions de precipitation par l'ammoniaque et les proprietes du diuranate d'ammonium, obtenue soit a partir de nitrate d'uranyle en solution, soit d'hexafluorure d'uranium gazeux. Dans chacun des cas, il est defini les procedes optima conduisant d'une part a un uranate susceptible d'etre traite ulterieurement en four de reduction-fluoruration pour l'obtention de tetrafluorure d'uranium et a un uranate pouvant convenir a la fabrication d'un oxyde d'uranium frittable d'autre part. En particulier, il est mis en evidence que le traitement des solutions de nitrate d'uranyle par des quantites stochiometriques d'ammoniaque entraine une precipitation totale de l'uranium avec moins de 1 mg/litre/U dans les eaux-meres, alors que celui de l'hexafluorure d'uranium necessite au moins huit fois la quantite stochiometrique. La mise au point d'un procede de precipitation en deux temps a l'avantage dans les deux cas de permettre avec le meme appareillage la fabrication de produits differents en faisant varier notamment le rapport des reactifs dans le premier temps. (auteur)

  3. Possibility of gas flow measurements using ionization produced by radioactive sources. Performance obtained using continuous and pulsed ionization; Etude des possibilites de mesure des debits gazeux par l'ionisation creee au moyen de sources radioactives performances obtenues par ionisation continue et par ionisation pulsee

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    Two methods for measuring gas flow have been studied, based on the ionization of the fluid by a radioactive source. In the first one, called the continuous method, use is made of the relationship between the flow and the ionic density at a point situated down-stream from the ionizing source. In the second method, called 'pulsed', the time for a burst of ions to pass between two points in the circuit is measured. An attempt has been made to predict and to justify theoretically the experimental results, and to determine to what extent these methods can provide absolute measurements or measurements requiring a calibration using known gas flows. These methods are characterized by the absence of moving parts or of parts under reduced pressure and can yield results with an accuracy of between a few per cent to a few tenths of a per cent. The information, provided in either analog or digital form, can be adapted for use in servo-mechanisms or automatic systems. Two applications of an industrial type are described; they concern gas-flow measurements in a railway braking circuit, and in tubes of 20 and 30 cm diameter. (author) [French] Deux methodes de mesure de debit gazeux ont ete etudiees, basees sur l'ionisation du fluide par une source radioactive. Dans la premiere, dite continue, on exploite la relation existant entre le debit et la densite ionique en un point situe a l'aval de la source ionisante. Dans la seconde, dite pulsee, on mesure le temps de transit de bouffees d'ions entre deux points de la conduite. On s'est efforce de prevoir et de justifier par la theorie les resultats experimentaux, et de preciser dans quelle mesure ces methodes peuvent fournir des mesures absolues ou necessitent un etalonnage a partir de debits connus. Caracterisees par l'absence d'organe mobile ou deprimogene, ces methodes sont susceptibles d'une precision de quelques pour-cent a quelques pour-mille. L'information, fournie sous forme

  4. Possibility of gas flow measurements using ionization produced by radioactive sources. Performance obtained using continuous and pulsed ionization; Etude des possibilites de mesure des debits gazeux par l'ionisation creee au moyen de sources radioactives performances obtenues par ionisation continue et par ionisation pulsee

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    Two methods for measuring gas flow have been studied, based on the ionization of the fluid by a radioactive source. In the first one, called the continuous method, use is made of the relationship between the flow and the ionic density at a point situated down-stream from the ionizing source. In the second method, called 'pulsed', the time for a burst of ions to pass between two points in the circuit is measured. An attempt has been made to predict and to justify theoretically the experimental results, and to determine to what extent these methods can provide absolute measurements or measurements requiring a calibration using known gas flows. These methods are characterized by the absence of moving parts or of parts under reduced pressure and can yield results with an accuracy of between a few per cent to a few tenths of a per cent. The information, provided in either analog or digital form, can be adapted for use in servo-mechanisms or automatic systems. Two applications of an industrial type are described; they concern gas-flow measurements in a railway braking circuit, and in tubes of 20 and 30 cm diameter. (author) [French] Deux methodes de mesure de debit gazeux ont ete etudiees, basees sur l'ionisation du fluide par une source radioactive. Dans la premiere, dite continue, on exploite la relation existant entre le debit et la densite ionique en un point situe a l'aval de la source ionisante. Dans la seconde, dite pulsee, on mesure le temps de transit de bouffees d'ions entre deux points de la conduite. On s'est efforce de prevoir et de justifier par la theorie les resultats experimentaux, et de preciser dans quelle mesure ces methodes peuvent fournir des mesures absolues ou necessitent un etalonnage a partir de debits connus. Caracterisees par l'absence d'organe mobile ou deprimogene, ces methodes sont susceptibles d'une precision de quelques pour-cent a quelques pour-mille. L'information, fournie sous forme analogique ou numerique, se prete a la realisation de

  5. Measurement of the relative yields of ψ (2 S ) to ψ (1 S ) mesons produced at forward and backward rapidity in p +p , p +Al , p +Au , and 3He+Au collisions at √{sNN}=200 GeV

    Science.gov (United States)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Alfred, M.; Andrieux, V.; Aoki, K.; Apadula, N.; Asano, H.; Ayuso, C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Blau, D. S.; Boer, M.; Bok, J. S.; Bownes, E. K.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Bumazhnov, V.; Butler, C.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Chujo, T.; Citron, Z.; Connors, M.; Cronin, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dion, A.; Diss, P. B.; Dixit, D.; Do, J. H.; Drees, A.; Drees, K. A.; Dumancic, M.; Durham, J. M.; Durum, A.; Dusing, J. P.; Elder, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukuda, Y.; Gal, C.; Gallus, P.; Garg, P.; Ge, H.; Giordano, F.; Glenn, A.; Goto, Y.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; He, X.; Hemmick, T. K.; Hill, J. C.; Hill, K.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Imai, K.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ito, Y.; Ivanishchev, D.; Jacak, B. V.; Jezghani, M.; Ji, Z.; Jia, J.; Jiang, X.; Johnson, B. M.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kanda, S.; Kang, J. H.; Kapukchyan, D.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khanzadeev, A.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, M.; Kimball, M. L.; Kimelman, B.; Kincses, D.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Komkov, B.; Kotler, J. R.; Kotov, D.; Kudo, S.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lajoie, J. G.; Lallow, E. O.; Lebedev, A.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leung, Y. H.; Lewis, N. A.; Li, X.; Li, X.; Lim, S. H.; Liu, L. D.; Liu, M. X.; Loggins, V.-R.; Loggins, V.-R.; Lovasz, K.; Lynch, D.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Malaev, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendez, A. R.; Mendoza, M.; Mignerey, A. C.; Mihalik, D. E.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I. M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagai, K.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Novotny, R.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, J. S.; Park, S.; Pate, S. F.; Patel, M.; Peng, J.-C.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Press, C. J.; Pun, A.; Purschke, M. L.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richford, D.; Rinn, T.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Runchey, J.; Safonov, A. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shukla, P.; Sickles, A.; Silva, C. L.; Silva, J. A.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Smith, K. L.; Snowball, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stepanov, M.; Stien, H.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Syed, S.; Sziklai, J.; Takeda, A.; Taketani, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarnai, G.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vazquez-Carson, S.; Velkovska, J.; Virius, M.; Vrba, V.; Vukman, N.; Wang, X. R.; Wang, Z.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; White, A. S.; Wong, C. P.; Woody, C. L.; Wysocki, M.; Xia, B.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yoo, J. H.; Yoon, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zhou, S.; Zou, L.; Phenix Collaboration

    2017-03-01

    The PHENIX Collaboration has measured the ratio of the yields of ψ (2 S ) to ψ (1 S ) mesons produced in p +p , p +Al , p +Au , and 3He+Au collisions at √{s NN}=200 GeV over the forward and backward rapidity intervals 1.2 <|y |<2.2 . We find that the ratio in p +p collisions is consistent with measurements at other collision energies. In collisions with nuclei, we find that in the forward (p -going or 3He-going) direction, the relative yield of ψ (2 S ) mesons to ψ (1 S ) mesons is consistent with the value measured in p +p collisions. However, in the backward (nucleus-going) direction, the ψ (2 S ) meson is preferentially suppressed by a factor of ˜2 . This suppression is attributed in some models to the breakup of the weakly bound ψ (2 S ) meson through final-state interactions with comoving particles, which have a higher density in the nucleus-going direction. These breakup effects may compete with color screening in a deconfined quark-gluon plasma to produce sequential suppression of excited quarkonia states.

  6. Fluid migration through geo-membrane seams and through the interface between geo-membrane and geo-synthetic clay liner; Contribution a l'etude des transferts de masse au niveau des joints de geomembrane et a l'interface entre geomembrane et geosynthetique bentonitique

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, M

    2005-03-15

    Composite liners are used to limit the contamination migration from landfills. Their successful performance is closely related with the geo-membrane as it provides the primary barrier to diffusive and advective transport of contaminants. Critical issues on the performance of the geo-membranes are the seams between geo-membrane panels and the inevitable defects resulting, for instance, from inadequate installation activities. In landfills, where high density polyethylene geo-membranes are usually used, seams are typically made by the thermal-hot dual wedge method. A literature review on quality control of the seams showed that, in situ, fluid-tightness of seams is evaluated in qualitative terms (pass/failure criteria), despite their importance to ensure appropriate performance of the geo-membranes as barriers. In addition, a synthesis of studies on geo-membrane defects indicated that defects varying in density from 0.7 to 15.3 per hectare can be found in landfills. Defects represent preferential flow paths for leachate. Various authors have developed analytical solutions and empirical equations for predicting the flow rate through composite liners due to defects in the geo-membrane. The validity of these methods for composite liners comprising a geo-membrane over a geo-synthetic clay liner (GCL) over a compacted clay liner (CCL) has never been studied from an experimental point of view. To address the problem of fluid migration through the geo-membrane seams, an attempt is made to provide a test method, herein termed as 'gas permeation pouch test', for assessing the quality of the thermal-hot dual wedge seams. This test consists of pressurizing the air channel formed by the double seam with a gas to a specific pressure and, then, measuring the decrease in pressure over time. From the pressure decrease, both the gas permeation coefficients, in steady state conditions, and the time constant, in unsteady state conditions, can be estimated. Experiments were

  7. Technological study of organic fluids; Etudes technologiques des fluides caloporteurs organique

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    Under contract to EURATOM (MM. VAN der VENNE and HANNAERT), the C.E.A. and the Progil Society have collaborated on a technological study of the terphenyls. The results obtained from the radiolysis and pyrolysis of the product OM2 (70 p. 100 m-terphenyl, 25 p. 100 o-terphenyl, 5 p. 100 p-terphenyl) are reported. Using two pile loops at temperatures up to 450 deg. C, a phenomena of accelerated pyrolysis on the radiolized material has been demonstrated. Some by-products of the petroleum industry have also been studied, with a view to finding substitutes for terphenyl. (author) [French] Le C.E.A. et la Societe PROGIL ont entrepris en commun sous contrat EURATOM (MM. VAN der VENNE et HANNAERT) une etude technologique des terphenyles. Les resultats de radiolyse et de pyrolyse obtenus sur le produit OM2 (70 p. 100 m-terphenyle, 25 p. 100 o-terphenyle. 5 p. 100 de p-terphenyle) sont exposes. L'exploitation de deux boucles en pile jusqu'a des temperatures de 450 deg. C a mis en evidence un phenomene de pyrolyse acceleree sur le produit radiolyse. On a etudie egalement quelques sous-produits de l'industrie petroliere dans le but de trouver des substituts au terphenyle. (auteur)

  8. Experiments on neutron-attenuation by ordinary concrete; Etude experimentale de l'attenuation des neutrons dans le beton ordinaire

    Energy Technology Data Exchange (ETDEWEB)

    Beauge, R; Millot, J P; Rastoin, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The penetration of fission-neutrons in water and glass mixtures has been investigated in the NAIADE facility. The slopes of the thermal and fast fluxes (the latter measured with a dosimeter) remain similar when the volume proportion of water is greater than 15 per cent. For smaller water-contents the measurements show the evidence of streaming, presumably due to slowing-down neutrons of energy smaller than 300 keV. Since a volume proportion of about 15 per cent of water in glass corresponds to the composition of ordinary concrete, the present work enables to predict the effects of a desiccation of concrete. Moreover, it is seen that there is no interest in increasing the proportion of water in ordinary concrete beyond the usual values (15-20 per cent). (author) [French] La propagation des neutrons de fission a ete etudiee dans les melanges verre-eau au moyen du dispositif NAIADE. La pente du flux thermique et la pente du flux rapide (obtenue au moyen d'un dosimetre) restent voisines lorsque la proportion d'eau dans le melange depasse 15 pour cent en volume. Pour des proportions d'eau inferieures les mesures mettent en evidence un 'streaming' de neutrons en ralentissement d'energie probablement inferieure a 300 keV. La composition des melanges verre-eau aux environs de 15 pour cent d'eau en volume correspondant au beton ordinaire, la presente etude permet de prevoir les effets d'une dessication du beton, et montre, en outre, qu'il n'y a pas interet a essayer d'augmenter la proportion d'eau dans le beton ordinaire au dela des valeurs usuelles (15 a 20 pour cent). (auteur)

  9. Etude des marges dans les circuits de commercialisation du porc au Cameroun

    Directory of Open Access Journals (Sweden)

    Tchoumboué, J.

    2004-01-01

    Full Text Available Study of Marketing Margins in Pig Marketing Channels in Cameroon. In order to provide a better knowledge of the influence of middlemen on livestock and meat prices in Cameroon, pig marketing margins were valued and compared in Yaounde, Douala and Dschang markets between September 1999 and August 2000. The main results showed that the marketing margins generated by the sale of fresh (31.97% and roasted (31.67% meats were significantly higher (p< 0.05, compared to pig (27.09%. The mean values of marketing margins in the different markets were higher at Yaounde (53.31%, followed by Douala (46.92% and lastly by Dschang (33.76%. Transaction costs analysis revealed significant variations (p< 0.05 between Yaounde (115.07 ± 49.74 and the other 2 markets, Douala (51.94 ± 19.48 and Dschang (39.10 ± 18.76, while the mean values of that parameter were 119.01 ± 78.40; 53.16 ± 14.95 and 61.51 ± 21.01 respectively for fresh and roasted meats and pig. However, in linking marketing margins to transaction costs, the study revealed that, while the sale of fresh and roasted meats allows a higher (p< 0.05 trader's profit in Douala and Dschang markets, compared to pig, the profitability for the three products seems to be the same (p> 0.05 in Yaounde market.

  10. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    KOUAME1*, Guy Fernand YAO2, .... activités de prospection et d'exploitation minière. On note toutefois la présence de forêt galerie, ..... fonction de la variation de pente sur les versants, comporte une différence significative au seuil de signification α ...

  11. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    été mené dans une serre en verre au département de Biologie (Université de ... taux de Na+ et K+, et fait l'analyse des paramètres physique et chimique du sol .... comportement de cette espèce : Atriplex. halimus vis-à-vis de cinq doses de ...

  12. Investigation of the glide modes of single crystals of beryllium; Etude des modes de glissement de monocristaux de beryllium

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-05-01

    glissement et des configurations de dislocations. L'etude du glissement prismatique a ete developpee beaucoup plus largement: l'influence de la temperature de la vitesse de deformation, de l'orientation initiale du plan de base et des plans prismatiques ont ete releves sur des echantillons d'orientation soignee, deformes en tension. On a egalement effectue quelques essais de microdeformation et observe de facon detaillee les lignes de glissement et les configurations de dislocations. Le comportement tres particulier observe n'est pas du aux impuretes, mais au glissement devie. On propose un mecanisme de blocage des dislocations permettant de l'expliquer. Comme ce mecanisme suppose que les dislocations a-bar peuvent aussi se dissocier sur les plans prismatiques [101-bar0] on examine cette possibilite et l'on propose plusieurs dissociations eventuelles dont la plus probable correspond a la transformation de phase hexagonale compacte {yields} cubique centree. En generalisant cette hypothese, on montre alors comment on peut rendre compte de la facilite relative des divers modes de glissement dans tous les metaux hexagonaux. (auteur)

  13. Distributions of charged hadrons associated with high transverse momentum particles in pp and Au+Au collisions at sqrt[sNN]=200 GeV.

    Science.gov (United States)

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Ganti, M S; Gaudichet, L; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grebenyuk, O; Gronstal, S; Grosnick, D; Guertin, S M; Gupta, A; Gutierrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Hughes, E; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Levine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mischke, A; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, D A; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; Vandermolen, A M; Varma, R; Vasilevski, I; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Vznuzdaev, M; Waggoner, W; Wang, F; Wang, G; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Yuting, B; Zanevski, Y V; Zhang, H; Zhang, W M; Zhang, Z P; Zhaomin, Z P; Zizong, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2005-10-07

    Charged hadrons in [EQUATION: SEE TEXT] associated with particles of [EQUATION: SEE TEXT] are reconstructed in pp and Au+Au collisions at sqrt[sNN]=200 GeV. The associated multiplicity and p magnitude sum are found to increase from pp to central Au+Au collisions. The associated p distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed.

  14. Recherche d'informations sur Internet au collège et au lycée : méthode, commentaires et exemples

    OpenAIRE

    Beaufils, Alain

    2004-01-01

    Etude menée par l'INRP-Tecné (recherche 40123).; Dans deux établissements scolaires de la banlieue parisienne (collège et lycée), nous avons mené une observation sur quelques élèves volontaires de quatrième et de seconde. Leur tâche consistait à répondre à une question portant sur un thème assez large en utilisant des informations trouvées sur Internet et en limitant leur recherche aux documents rédigés en langue française. L'activité a eu lieu au CDI et comportait une séance d'entraînement s...

  15. Implementing Formative Assessment in Engineering Education: The Use of the Online Assessment System Etude

    Science.gov (United States)

    Dopper, Sofia M.; Sjoer, Ellen

    2004-01-01

    This article describes the possibilities offered by the online assessment system Etude to achieve the benefits of formative assessment. In order to find out the way this works in practice, we carried out an experiment with the use of Etude for formative assessment in the course on collaborative report writing. Results show that online formative…

  16. INDRA at GSI; INDRA au GSI

    Energy Technology Data Exchange (ETDEWEB)

    Bougault, R.; Bocage, F.; Durand, D.; Lopez, O.; Steckmeyer, J.C.; Tamain, B.; Vient, E. [Lab. de Physique Corpusculaire, Caen Univ., 14 (France); Collaboration INDRA: IPN-Orsay, DAPNIA-Saclay, SUBATECH-Nantes, IPN- Lyon, GANIL-Caen

    1997-12-31

    In connection to the decision of installing the INDRA detector by the SIS synchrocyclotron at GSI (Darmstadt, Germany) the report presents the tasks taken into account by the LPC-Caen. These refer to the detector displacement and (mechanical) installation at GSI, the tests before beam (i.e. electronics acquisition software, detectors, etc.) as well as the data acquisition and processing. The physical pro-arguments mention the possibility of disposing of heavy ion beams in a range from 50 MeV to several GeV/nucleon so extending the study of multifragmentation done at GANIL between 30 and 90 MeV/nucleon. More specific, the scientific program of INDRA at GSI inserts studies between those done at around Fermi energy, were the reaction mechanisms are of type of deep inelastic scattering/incomplete fusion, and the studies in the relativistic energy domain where the individual properties of nucleons and transparency of nuclear matter implies mechanisms of the participant-spectator type (fire-ball creation). Also mentioned as fields of extensive studies are: the multifragmentation and its fundamental relation with the nuclear matter equation of state, the role of reaction dynamics in the appearance of collective effects of the radial flow type and its relations with the nuclear compressibility and phase transitions and the thermodynamics of nuclear matter. It appeared that the heavy systems Xe + Sn and Au + Au are the best compromise for the different topics to be approached. The bombarding energies extend from 50 to 150 MeV/nucleon. The report ends with the table giving for six heavy systems (Xe + Sn, Au + Au, C + Au, Ar + Au and P + Au) the required bombarding energies 15 refs.

  17. Study of thermocouples for control of high temperatures; Etude de thermocouples pour le reperage des hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Villamayor, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Faculte des Sciences de l' Universite de Lyon - 69 (France)

    1967-07-01

    Previous works have shown that the tungsten-rhenium alloys thermocouples were a good instrument for control of high temperatures. From its, the author has studied the W/W 26 per cent and W 5 per cent Re/W 26 per cent Re french manufactured thermocouples and intended for control of temperatures in nuclear reactors until 2300 deg. C. In 'out-pile' study he determines the general characteristics of these thermocouples: average calibration curves, thermal shocks influence, response times, and alloys allowing the cold source compensation. The evolution of these thermocouples under thermal neutron flux has been determined by 'in-pile' study. The observations have led the author to propose a new type of thermocouples settled of molybdenum-columbium alloys. (author) [French] Des travaux anterieurs ont montre que les thermocouples des alliages tungstene-rhenium etaient susceptibles de reperer avec precision des hautes temperatures. A partir de la, l'auteur a etudie las thermocouples W/W 26 pour cent Re et W 5 pour cent Re/W 26 pour cent Re de fabrication francaise et destines au controle des temperatures dans les reacteurs nucleaires, jusqu'a 2300 deg. C Dans l'etude 'hors-pile' il a determine les caracteristiques generales de ces thermocouples: courbes d'etalonnage moyen, influence des chocs thermiques, temps de reponse, et alliages assurant la compensation de soudure froide. L'etude 'en-pile' a permis de rendre compte de l'evolution de ces thermocouples sous flux neutroniques. Les phenomenes observes ont conduit l'auteur a proposer un nouveau type de thermocouples constitues d'alliages molybdene-niobium. (auteur)

  18. Study of radio-active ions in the atmosphere; Etude des ions radioactifs de l'atmosphere

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-01-01

    A comparative study is made of active, deposits of radon and thoron in suspension in the atmosphere by means of {alpha} radiation counting, using ZELENY tubes, scattering equipment, filter papers or membranes. It has been possible to show the existence of small and large ions which are negative and positive, as well as of neutral radio-active nuclei; their properties are studied. A theoretical interpretation of the results is presented. The average content of radon (using the Ra A concentration) and of Th B in the air has been determined. The radioactive equilibrium between radon and its daughter products in atmospheric air are examined. The techniques developed for active radon and thoron deposits are applied to the study of artificial radio-activity, the analyses being carried out by means of {gamma} spectrometry. (author) [French] On effectue une etude comparative entre les depots actifs du radon et du thoron en suspension dont l'atmosphere a l'aide de comptages de rayonnement {alpha}, en utilisant des tubes de ZELENY, une batterie de diffusion, des papiers filtres ou des membranes. On met ainsi en evidence la presence de petits et gros ions negatifs et positifs, ainsi que celle de noyaux neutres radioactifs, et on etudie leurs proprietes. Une Interpretation theorique des resultats obtenus est developpee. On determine la teneur moyenne de l'air en radon (a partir de la concentration en Ra A) et en Th B. L'equilibre radioactif entre le radon et ses descendants, dans l'air atmospherique, est examine. Les Techniques mises au point pour les depots actifs du radon et du thoron sont appliquees a l'etude de la radioactivite artificielle, les depouillements s'effectuant par spectrometrie {gamma}. (auteur)

  19. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  20. Structure of eutectic alloys of Au with Si and Ge

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, S. [Faculty of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan)], E-mail: takeda@rc.kyushu-u.ac.jp; Fujii, H. [Graduate School of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Kawakita, Y. [Faculty of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Tahara, S.; Nakashima, S. [Graduate School of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Kohara, S.; Itou, M. [Japan Synchrotron Radiation Research Institute, 1-1-1 Koto Sayo-cho, Sayo Hyogo 679-5198 (Japan)

    2008-03-06

    Au-Si and Au-Ge alloy systems have a deep eutectic point in the Au-rich concentration region where the melting point falls down to 633 K. In order to investigate the liquid structure in relation to the glass-forming tendency of these alloys, high-energy X-ray diffraction measurements have been carried out at the eutectic composition and at compositions with excess amounts of Au or IVb element. The nearest neighbor correlations in the eutectic liquids are intense and sharp in the pair distribution function and exhibit a rather small temperature dependence in comparison with those alloys of other than the eutectic composition. Structural models for these liquid alloys are proposed with the aid of reverse Monte Carlo simulation. The reproduced atomic arrangements around the eutectic region exhibit a substitutional-type structure where the dense random packing of Au atoms is preserved and Si or Ge atoms occupy the Au-sites at random.

  1. Castor and Pollux - shielded cells for studying fuel treatment processes; Castor et Pollux chaines blindees d'etudes de procedes de traitement de combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Faudot, G; Bathellier, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    CASTOR and POLLUX, two alpha, beta, gamma cells are described in the present paper. They are located in the CEN at Fontenay-aux-Roses (France). They are designed for improvement studies of the various aqueous separation processes used in irradiated fuels reprocessing plants. Located in the same air-tight steel encasement, they arc inter-connected by a pneumatic transfer. These two cells have a similar in-line conception and they include: a gamma shielding in lead of 10 cm of thickness; an inner air-tight box, made with stainless steel and plexiglas, is maintained in lowering in comparison to room pressure. Eleven Hobson model seven master-slave manipulators allow inner manipulations. Then the inner equipment is described briefly. (author) [French] Le present document decrit les cellules alpha, beta, gamma CASTOR et POLLUX edifiees au Centre d'Etudes Nucleaires de Fontenay-aux-Roses. Elles sont destinees aux etudes visant a l'amelioration des procedes de separation par voie aqueuse utilises dans les usines de retraitement des combustibles irradies. Ces deux chaines, implantees dans le meme caisson et reliees par convoyeur pneumatique, sont de conception identique et comprennent: une protection biologique constituee par 10 cm d'epaisseur de plomb; une enceinte interieure etanche alpha, en acier inoxidable et plexiglas, maintenue en depression. Des telemanipulateurs Hobson, modele 7, permettent les manipulations interieures. On decrit ensuite brievement les installations annexes. (auteur)

  2. The ultrasonic copper and brass decontamination study; Etude de la decontamination du cuivre et des laitons en presence d'ultra-sons

    Energy Technology Data Exchange (ETDEWEB)

    Courtault, J; Kerdelleau, J de; Mestre, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The use of ultra-sounds as a decontamination technic does not bring an absolute solution. As a function of the materials it seemed necessary to find what was the optimum conditions for using the ultra-sounds and to define not only the ultra-sonic factors but also the chemical solutions which bring some appreciable decontamination factors without bringing any too important corrosion processus. This report gives the results of this study applied to copper and brass. This study allowed to select some effective treatment baths on the two types of contamination: plutonium and fission products. (authors) [French] L'emploi des ultra-sons comme technique de decontamination n'amene pas une solution absolue. Il est apparu necessaire de rechercher en fonction de la nature du materiau a decontaminer quelles etaient les conditions optimales d'utilisation des ultra-sons et de definir alors non seulement les facteurs ultrasoniques mais encore les solutions chimiques qui apportent des facteurs de decontamination appreciables sans amener des phenomenes de corrosion trop importants. Ce rapport donne les resultats de cette etude appliquee au cuivre et aux laitons. Cette etude a permis de selectionner des bains de traitement efficaces dans les deux cas de contamination: plutonium et produits de fission. (auteurs)

  3. A study of internal contamination levels resulting from {sup 90}Sr and {sup 137}Cs environmental pollution. The influence of different factors; Etude des niveaux de contamination interne resultant d'une pollution de l'environnement par le {sup 90}Sr et le {sup 137}Cs influence des differents parametres

    Energy Technology Data Exchange (ETDEWEB)

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

    1970-07-01

    This study includes two parts. The purpose of the former one is to try and evaluate the amounts of {sup 90}Sr and {sup 137}Cs dietary intakes as a function of age with a view to assessing internal exposure doses and estimating the critical age, and to study the relative significance of the several factors it depends on. The data used are both the results of dietary surveys made in 11 districts of the European community from which the evolution of the consumed amounts of 13 groups of foodstuffs, as a function of age was derived, and the mean factors of contamination pathways. The variability of some factors is very large and an attempt is made to assess their significance on the whole contamination; also, the influence of the various diets has been emphasized. The purpose of the second part is to assess, doses as a function of age in the case of protracted exposure on the basis of the aforesaid results and radiobiological factors derived from bibliographic states of the arts. An assessment is made of body burdens and mean doses (either to the skeleton or the whole body according to the radionuclides) originating either from a direct unitary exposure or from situations implying both modes of exposure. As assumed only the diets vary with the districts, thus the results reflect their significance which should be corrected, for a more accurate assessment of the dose variability, by the significance of human and transfer factors. (author) [French] Cette etude comprend deux parties. L'objet de la premiere partie est a la fois un essai d'evaluation en fonction de l'age des quantites de strontium 90 et de cesium 137 ingerees avec les aliments dans la perspective d'une application a l'estimation des doses d'irradiation interne et a la recherche de l'age critique, et une etude de l'influence relative des divers parametres dont elle depend. Les donnees utilisees sont, d'une part, les resultats des enquetes alimentaires faites en onze regions de la Communaute Europeenne dont on

  4. A study of internal contamination levels resulting from {sup 90}Sr and {sup 137}Cs environmental pollution. The influence of different factors; Etude des niveaux de contamination interne resultant d'une pollution de l'environnement par le {sup 90}Sr et le {sup 137}Cs influence des differents parametres

    Energy Technology Data Exchange (ETDEWEB)

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

    1970-07-01

    This study includes two parts. The purpose of the former one is to try and evaluate the amounts of {sup 90}Sr and {sup 137}Cs dietary intakes as a function of age with a view to assessing internal exposure doses and estimating the critical age, and to study the relative significance of the several factors it depends on. The data used are both the results of dietary surveys made in 11 districts of the European community from which the evolution of the consumed amounts of 13 groups of foodstuffs, as a function of age was derived, and the mean factors of contamination pathways. The variability of some factors is very large and an attempt is made to assess their significance on the whole contamination; also, the influence of the various diets has been emphasized. The purpose of the second part is to assess, doses as a function of age in the case of protracted exposure on the basis of the aforesaid results and radiobiological factors derived from bibliographic states of the arts. An assessment is made of body burdens and mean doses (either to the skeleton or the whole body according to the radionuclides) originating either from a direct unitary exposure or from situations implying both modes of exposure. As assumed only the diets vary with the districts, thus the results reflect their significance which should be corrected, for a more accurate assessment of the dose variability, by the significance of human and transfer factors. (author) [French] Cette etude comprend deux parties. L'objet de la premiere partie est a la fois un essai d'evaluation en fonction de l'age des quantites de strontium 90 et de cesium 137 ingerees avec les aliments dans la perspective d'une application a l'estimation des doses d'irradiation interne et a la recherche de l'age critique, et une etude de l'influence relative des divers parametres dont elle depend. Les donnees utilisees sont, d'une part, les resultats des enquetes alimentaires faites en

  5. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, S.; Shimakura, H. [Niigata University of Pharmacy and Applied Life Sciences, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Tahara, S. [Faculty of Science, University of the Ryukyus, Nishihara-cho, Okinawa 903-0213 (Japan); Okada, T. [Niigata College of Technology, Kamishin’eicho, Nishi-ku, Niigata 950-2076 (Japan)

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  6. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    J. Aouam sous le nom de schistes Mokattam et schistes cloisonnés. c- Le dévonien : Les dépôts du Dévonien inférieur sont constitués d'argilites indiquant une sédimentation calme de plate forme externe, qui va s'enrichir en nodules et calcaire. Cette sédimentation carbonatée va subir une perturbation, puisqu'au Dévonien ...

  7. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    Sa valorisation passe par l'étude de sa biologie en milieu naturel, puis en conditions contrôlées. Les variations saisonnières de la croissance et de la capacité reproductive de l'algue rouge Hypnea musciformis ont été suivies durant deux années dans deux localités différentes au niveau de la côte atlantique marocaine.

  8. Study and installation of concrete shielding in the civil engineering of nuclear construction (1960); Etude et mise en place des betons de protection dans le genie civil des ouvrages nucleaires (1960)

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    The object of this report is to give technical information about high density concretes which have become very important for radiation biological shielding. The most generally used heavy aggregates (barytes, ilmenite, ferrophosphorus, limonite, magnetite and iron punching) to make these concretes are investigated from the point of view prospecting and physical and chemical characteristics. At first, a general survey of shielding concretes is made involving the study of components, mixing and placing methods, then, a detailed investigation of some high density concretes: barytes concrete, with incorporation of iron punching or iron shot, ferrophosphorus concrete, ilmenite concrete and magnetite concrete, more particularly with regard to grading and mix proportions and testing process. To put this survey in concrete form, two practical designs are described such as they have been carried out at the Saclay Nuclear Station. Specifications are given for diverse concretes and for making the proton-synchrotron 'Saturne' shielding blocks. (author) [French] Ce rapport a pour objet de donner des precisions techniques au sujet des betons a haute densite qui ont pris une grande importance pour la protection biologique contre les rayonnements. Les agregats lourds les plus couramment utilises (barytine, ilmenite, ferrophosphore, limonite, magnetite et riblons) pour la fabrication de ces betons, sont examines du point de vue prospection et caracteristiques physiques et chimiques. On procede d'abord a une etude generale des betons de protection comprenant l'etude des constituants, de la confection et de la mise en place, ensuite, a un examen detaille de quelques betons a haute densite: betons a base de barytine, avec incorporation de riblons ou de grenaille de fonte, betons au ferrophosphore, a base d'ilmenite ou de magnetite, notamment en ce qui concerne la granulometrie, la composition, le dosage et les processus d'essais. Pour concretiser ces etudes, deux applications pratiques

  9. Study and installation of concrete shielding in the civil engineering of nuclear construction (1960); Etude et mise en place des betons de protection dans le genie civil des ouvrages nucleaires (1960)

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    The object of this report is to give technical information about high density concretes which have become very important for radiation biological shielding. The most generally used heavy aggregates (barytes, ilmenite, ferrophosphorus, limonite, magnetite and iron punching) to make these concretes are investigated from the point of view prospecting and physical and chemical characteristics. At first, a general survey of shielding concretes is made involving the study of components, mixing and placing methods, then, a detailed investigation of some high density concretes: barytes concrete, with incorporation of iron punching or iron shot, ferrophosphorus concrete, ilmenite concrete and magnetite concrete, more particularly with regard to grading and mix proportions and testing process. To put this survey in concrete form, two practical designs are described such as they have been carried out at the Saclay Nuclear Station. Specifications are given for diverse concretes and for making the proton-synchrotron 'Saturne' shielding blocks. (author) [French] Ce rapport a pour objet de donner des precisions techniques au sujet des betons a haute densite qui ont pris une grande importance pour la protection biologique contre les rayonnements. Les agregats lourds les plus couramment utilises (barytine, ilmenite, ferrophosphore, limonite, magnetite et riblons) pour la fabrication de ces betons, sont examines du point de vue prospection et caracteristiques physiques et chimiques. On procede d'abord a une etude generale des betons de protection comprenant l'etude des constituants, de la confection et de la mise en place, ensuite, a un examen detaille de quelques betons a haute densite: betons a base de barytine, avec incorporation de riblons ou de grenaille de fonte, betons au ferrophosphore, a base d'ilmenite ou de magnetite, notamment en ce qui concerne la granulometrie, la composition, le dosage et les processus d'essais. Pour concretiser ces

  10. 98 Etude Comparative du Systeme Phonematique et Tonal des ...

    African Journals Online (AJOL)

    98. Etude Comparative du Systeme Phonematique et Tonal des. Deux Parlers: Le Yoruba du Nigeria et L'itsa Parle en. Republique du Benin. Ajani Akinwumi Lateef et Ayuba G. Ajibabi http://dx.doi./org/10.4314/ujah.v18i3.5. Résume. En ce début de l'époque ou la mondialisation et la coexistence des peuples dans le ...

  11. Microstructural evolution of Au/TiO{sub 2} nanocomposite films: The influence of Au concentration and thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Borges, J., E-mail: joelborges@fisica.uminho.pt [Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Centro/Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Kubart, T.; Kumar, S.; Leifer, K. [Solid-State Electronics, Department of Engineering Sciences, Uppsala University, P.O. Box 534, Uppsala SE-751 21 (Sweden); Rodrigues, M.S. [Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Centro/Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Duarte, N.; Martins, B.; Dias, J.P. [Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Cavaleiro, A. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Vaz, F. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Centro/Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-04-01

    Nanocomposite thin films consisting of a dielectric matrix, such as titanium oxide (TiO{sub 2}), with embedded gold (Au) nanoparticles were prepared and will be analysed and discussed in detail in the present work. The evolution of morphological and structural features was studied for a wide range of Au concentrations and for annealing treatments in air, for temperatures ranging from 200 to 800 °C. Major findings revealed that for low Au atomic concentrations (at.%), there are only traces of clustering, and just for relatively high annealing temperatures, T ≥ 500 °C. Furthermore, the number of Au nanoparticles is extremely low, even for the highest annealing temperature, T = 800 °C. It is noteworthy that the TiO{sub 2} matrix also crystallizes in the anatase phase for annealing temperatures above 300 °C. For intermediate Au contents (5 at.% ≤ C{sub Au} ≤ 15 at.%), the formation of gold nanoclusters was much more evident, beginning at lower annealing temperatures (T ≥ 200 °C) with sizes ranging from 2 to 25 nm as the temperature increased. A change in the matrix crystallization from anatase to rutile was also observed in this intermediate range of compositions. For the highest Au concentrations (> 20 at.%), the films tended to form relatively larger clusters, with sizes above 20 nm (for T ≥ 400 °C). It is demonstrated that the structural and morphological characteristics of the films are strongly affected by the annealing temperature, as well as by the particular amounts, size and distribution of the Au nanoparticles dispersed in the TiO{sub 2} matrix. - Highlights: • Au:TiO{sub 2} films were produced by magnetron sputtering and post-deposition annealing. • The Au concentration in the films increases with the Au pellet area. • Annealing induced microstructural changes in the films. • The nanoparticle size evolution with temperature depends on the Au concentration.

  12. Mineralogical, stable isotope, and fluid inclusion studies of spatially related porphyry Cu and epithermal Au-Te mineralization, Fakos Peninsula, Limnos Island, Greece

    Science.gov (United States)

    Fornadel, Andrew P.; Voudouris, Panagiotis Ch.; Spry, Paul G.; Melfos, Vasilios

    2012-05-01

    The Fakos porphyry Cu and epithermal Au-Te deposit, Limnos Island, Greece, is hosted in a ~20 Ma quartz monzonite and shoshonitic subvolcanic rocks that intruded middle Eocene to lower Miocene sedimentary basement rocks. Metallic mineralization formed in three stages in quartz and quartz-calcite veins. Early porphyry-style (Stage 1) metallic minerals consist of pyrite, chalcopyrite, galena, bornite, sphalerite, molybdenite, and iron oxides, which are surrounded by halos of potassic and propylitic alteration. Stage 2 mineralization is composed mostly of quartz-tourmaline veins associated with sericitic alteration and disseminated pyrite and molybdenite, whereas Stage 3, epithermal-style mineralization is characterized by polymetallic veins containing pyrite, chalcopyrite, sphalerite, galena, enargite, bournonite, tetrahedrite-tennantite, hessite, petzite, altaite, an unknown cervelleite-like Ag-telluride, native Au, and Au-Ag alloy. Stage 3 veins are spatially associated with sericitic and argillic alteration. Fluid inclusions in quartz from Stage 1 (porphyry-style) mineralization contain five types of inclusions. Type I, liquid-vapor inclusions, which homogenize at temperatures ranging from 189.5°C to 403.3°C have salinities of 14.8 to 19.9 wt. % NaCl equiv. Type II, liquid-vapor-NaCl, Type III liquid-vapor-NaCl-XCl2 (where XCl is an unknown chloride phase, likely CaCl2), and Type IV, liquid-vapor-hematite ± NaCl homogenize to the liquid phase by liquid-vapor homogenization or by daughter crystal dissolution at temperatures of 209.3 to 740.5 °C, 267.6 to 780.8 °C, and 357.9 to 684.2 °C, respectively, and, Type V, vapor-rich inclusions. Stage 2 veins are devoid of interpretable fluid inclusions. Quartz from Stage 3 (epithermal-style) veins contains two types of fluid inclusions, Type I, liquid-vapor inclusions that homogenize to the liquid phase (191.6 to 310.0 °C) with salinities of 1.40 to 9.73 wt. % NaCl equiv., and Type II, vapor-rich inclusions. Mixing

  13. Theoretical study for a digital transfer function analyser; Etude theorique pour un transferometre digital

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    This study deals with the harmonic analysis of the instantaneous counting rate of a pulse train. This arises from using a fission chamber for reactivity to power transfer function measurements by oscillation methods in reactors. The systematical errors due to the sampling process are computed. The integration carried out when sampling the signal modifies the formulae of the Nyquist theorem on spectrum folding. The statistical errors due to the noise are analysed: it is shown that the bandwidth of the spectral window applied to the noise frequency spectrum is equal to the inverse of the time duration of the experiment. A dead time of 25 per cent of the sampling time does not increase appreciably the bandwidth. A new method is proposed afterwards yielding very approximate results of the Fourier analysis during the experiment. The systematical errors arising from the measuring process are determined, and it is shown that the bandwidth of the corresponding spectral window is still given by the inverse of the time duration of the experiment. (author) [French] Cette etude se rapporte a l'analyse harmonique de la valeur instantanee du taux de comptage d'une suite d'impulsions. On rencontre ce probleme dans l'utilisation de chambres a fission pour les mesures de fonction de transfert reactivite-puissance par la methode d'oscillation dans les piles. On calcule l'erreur systematique due au processus d'echantillonnage ou l'integration operee modifie les formules classiques de recouvrement du spectre. On analyse ensuite les erreurs statistiques dues au bruit de fond. On montre que la largeur de bande de la fenetre spectrale appliquee au spectre de puissance du bruit est donnee par l'inverse du temps de mesure. Un temps mort de 25 pour cent du temps de prelevement n'accroit pas sensiblement cette largeur de bande. On propose ensuite un procede simple qui permet d'obtenir, en cours d'experience, des resultats tres approches de l'analyse de Fourier. On determine les erreurs

  14. A contribution to the structural and kinetic study of the slow transformation of an iron or uranium alpha crystal; Contribution a l'etude structurale et cinetique de la transformation lente d'un cristal de fer alpha ou d'uranium alpha

    Energy Technology Data Exchange (ETDEWEB)

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

    1958-12-15

    transformation {alpha} {yields} {gamma} {yields} {alpha} du fer ou de la double transformation {alpha} {yields} {beta} {yields} {alpha} de l'uranium. Nous avons montre que ce phenomene ne se produit pas dans le cas des metaux tres purs mais seulement lorsque le metal renferme des traces d'impuretes notamment du carbone. Le cristal unique n'est regenere que si l'on a soin de ne pas depasser de plus de quelques degres la temperature de fin de transformation. On retrouve ce phenomene dans les agregats polycristallins: les orientations des cristaux constitutifs ce l'agregat sont conservees bien que les joints de grains subissent des deplacements considerables. 2- L'etude cinetique de la transformation au refroidissement d'une part, l'analyse de la texture de la phase {gamma} dans le cas du fer, de l'autre, demontrent que la regeneration resulte de la conservation de germes de la phase {alpha} dans la phase de haute temperature. Ces germes paraissent relativement stables car au bout de 24 h de sejour a la temperature d'experience ils conservent leurs proprietes. 3- L'etude des macles de fer {gamma} engendrees par la transformation {alpha} {yields} {gamma} nous a permis de demontrer qu'il n'existe pas de relation d'orientation dans la transformation {alpha} {yields} {gamma} du fer pur. 4- Grace a l'elaboration d'une pellicule d'oxyde epitaxique sur la surface du fer {gamma}, nous avons mis en evidence un nouveau type de macles de transformation du fer {alpha} qui croissent dans une direction [110] et dont le plan de contact est (110). Formees de lamelles tres fines, ces macles par contact sont instables et se transforment en macles par penetration dont chaque element, beaucoup plus gros, provient du grossissement d'un certain nombre de lamelles. (auteur)

  15. Le CRDI au Ghana

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

    pour prévenir le paludisme, des études ayant démontré que leur utilisation pouvait réduire considérablement la mortalité infantile. Les chercheurs ont également suggéré aux gouvernements différents moyens pour inciter les gens à acheter les moustiquaires et à les utiliser correctement. Les TI au service de la démocratie.

  16. Mise au point

    African Journals Online (AJOL)

    et traité à temps, le risque de complications et de morbidité peut être écarté. Les auteurs rapportent 2 cas de kystes de la vallécule. La tomodensitométrie a confirmé la présence d'une formation kystique prenant origine au niveau de la val- lécule. Une laryngoscopie directe a été faite pour les 2 patients sous anesthésie ...

  17. Contribution to the study of the vertical molten zone process (1963); Contribution a l'etude du procede de la zone fondue verticale (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

    Construction and use of several molten zone apparatuses operating either vertically or horizontally. Efficient purification of uranyl nitrate hexahydrate but less successful in the case of other hydrated double salts and of zirconyl chloride in the hydrochloric gel form. Demonstration and study of the dissymmetry in the direction of the transport of the impurity during, the purification by a vertical molten zone process. (author) [French] Construction et utilisation de plusieurs appareils de zone fondue travaillant soit en vertical, soit en horizontal. Purification efficace du nitrate d'uranyle hexahydrate mais peu significative dans le cas des autres couples de sels hydrates et du chlorure de zirconyle a l'etat de gel chlorhydrique. Mise en evidence et etude de la dissymetrie sur le sens de transport de l'impurete au cours de la purification par zone fondue verticale. (auteur)

  18. Contribution to the study of samarium-151 excited levels; Contribution a l'etude des niveaux excites du samarium-151

    Energy Technology Data Exchange (ETDEWEB)

    Locard, P [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, 38 (France)

    1967-07-01

    The nucleus of {sup 151}Sm, which has 89 neutrons, happens to be on the lower edge of the deformed nuclei of region II. Therefore, the study of its levels is very interesting for the verification of the goodness of the collective models for deformed nuclei when the deformation is small (we introduce these models in the first chapter). {sup 151}Sm has often been studied, but the direct gamma spectrum measured with a lithium drift-germanium detector (chapter 3) shows many high energy transitions which did not appear in the previous level schemes. In order to settle these transitions, we have undertaken gamma-gamma coincidence spectra (as well as sum-coincidence spectra) experiments with a scintillation spectrometer designed in our laboratory (chapter 2). The investigation of the intensities of these coincidences leads us to modify the last proposed level schemes: we suppress the levels at 405,5 and 650 keV, we add levels at 245,6 - 306,6 - 522 - 952 and 962 keV. We have also verified the multipolarities of the main transitions and measured the half-lives of a few levels (chapter 3) (we find a half-life of 1.1 {+-} 0.5 nanosecond for the level at 167,7 keV). In chapter 4, we compare our results to the predictions of the models described in chapter 1. (author) [French] Le noyau de {sup 151}Sm, qui possede 89 neutrons, se trouve a la limite inferieure des noyaux deformes de la region II. L'etude de ses niveaux excites est donc d'un interet tout particulier pour la verification de la validite des differents modeles collectifs pour les noyaux deformes, lorsque la deformation est petite (nous introduisons ces modeles dans un premier chapitre). Le {sup 151}Sm a deja fait l'objet de nombreuses etudes, mais le spectre gamma direct fait avec une jonction de germanium compense au lithium (chapitre 3), nous a montre l'existence d'un grand nombre de transitions de hautes energies qui ne sont pas placees dans les schemas proposes jusqu'a ce jour. Pour preciser la place de ces

  19. Structural and optical studies of Au doped titanium oxide films

    International Nuclear Information System (INIS)

    Alves, E.; Franco, N.; Barradas, N.P.; Nunes, B.; Lopes, J.; Cavaleiro, A.; Torrell, M.; Cunha, L.; Vaz, F.

    2012-01-01

    Thin films of TiO 2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 °C. The undoped films were implanted with Au fluences in the range of 5 × 10 15 Au/cm 2 –1 × 10 17 Au/cm 2 with a energy of 150 keV. At a fluence of 5 × 10 16 Au/cm 2 the formation of Au nanoclusters in the films is observed during the implantation at room temperature. The clustering process starts to occur during the implantation where XRD estimates the presence of 3–5 nm precipitates. After annealing in a reducing atmosphere, the small precipitates coalesce into larger ones following an Ostwald ripening mechanism. In situ XRD studies reveal that Au atoms start to coalesce at 350 °C, reaching the precipitates dimensions larger than 40 nm at 600 °C. Annealing above 700 °C promotes drastic changes in the Au profile of in situ doped films with the formation of two Au rich regions at the interface and surface respectively. The optical properties reveal the presence of a broad band centered at 550 nm related to the plasmon resonance of gold particles visible in AFM maps.

  20. Structural and optical studies of Au doped titanium oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Alves, E., E-mail: ealves@itn.pt [Instituto Tecnologico e Nuclear (ITN), 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Gama Pinto, 21649-003 Lisboa (Portugal); Franco, N.; Barradas, N.P. [Instituto Tecnologico e Nuclear (ITN), 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Gama Pinto, 21649-003 Lisboa (Portugal); Nunes, B. [Instituto Tecnologico e Nuclear (ITN), 2686-953 Sacavem (Portugal); Lopes, J. [Instituto Superior de Engenharia de Lisboa (Portugal); Cavaleiro, A. [SEC-CEMUC - Universidade de Coimbra, Dept. Eng. Mecanica, Polo II, 3030-788 Coimbra (Portugal); Torrell, M.; Cunha, L.; Vaz, F. [Centro de Fisica, Universidade do Minho, 4800-058 Guimaraes (Portugal)

    2012-02-01

    Thin films of TiO{sub 2} were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 Degree-Sign C. The undoped films were implanted with Au fluences in the range of 5 Multiplication-Sign 10{sup 15} Au/cm{sup 2}-1 Multiplication-Sign 10{sup 17} Au/cm{sup 2} with a energy of 150 keV. At a fluence of 5 Multiplication-Sign 10{sup 16} Au/cm{sup 2} the formation of Au nanoclusters in the films is observed during the implantation at room temperature. The clustering process starts to occur during the implantation where XRD estimates the presence of 3-5 nm precipitates. After annealing in a reducing atmosphere, the small precipitates coalesce into larger ones following an Ostwald ripening mechanism. In situ XRD studies reveal that Au atoms start to coalesce at 350 Degree-Sign C, reaching the precipitates dimensions larger than 40 nm at 600 Degree-Sign C. Annealing above 700 Degree-Sign C promotes drastic changes in the Au profile of in situ doped films with the formation of two Au rich regions at the interface and surface respectively. The optical properties reveal the presence of a broad band centered at 550 nm related to the plasmon resonance of gold particles visible in AFM maps.

  1. Genetic cytological and biochemical study of a tomato chlorophyll mutant of the xanthic type, obtained by irradiation of the seeds; Etude genetique, cytologique et biochimique d'un mutant chlorophyllien de tomate du type xantha, obtenu par irradiation de graines

    Energy Technology Data Exchange (ETDEWEB)

    Lefort, M; Duranton, J; Galmiche, J M; Roux, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Irradiation of Lycopersicum aesculantum seeds with increasing doses of X-rays and thermal neutrons leads to the appearance of chlorophyll mutations in the descendants of the irradiated seeds. A genetic study of one of these mutants of the xanthic type showed that it was a recessive mutant with typical mono-genetic separation, while the cytological study demonstrated that the differentiation of the plast stopped at the stage of elementary lamella. Finally it is shown that in the light, the mutation brings about a very large deviation of the carbon metabolism towards the synthesis of amino acids and proteins, at the expense of that of glucosides. (author) [French] L'irradiation de graines de Lycopersicum Aesculantum avec des doses croissantes de rayons X et de neutrons thermiques entraine l'apparition de mutations chlorophylliennes dans la descendance des graines irradiees. L'etude genetique d'un de ces mutants du type xantha a montre qu'il s'agissait d'un mutant recessif a disjonction monogenique typique, tandis que l'etude cytologique a revele que la differentiation du plaste s'arretait au stade de lamelles elementaires. Il est apparu enfin qu'a la lumiere la mutation entrainait une deviation tres importante du metabolisme du carbone vers la synthese des acides amines et des proteines, au detriment de celle des glucides. (auteur)

  2. Radio-vulcanization of natural rubber in the latex phase. Study of an experimental 1 tonne per hour production; Radio-vulcanisation du caoutchouc naturel en phase latex. Etude d'une production experimentale de 1 tonne par heure

    Energy Technology Data Exchange (ETDEWEB)

    Leveque, P; Puig, J R; Roudeix, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    After briefly reviewing the main research carried out on the radio-vulcanization of latex and elastomers, a description is given of 4 types of cell which have been used successively with a view to industrial irradiation. They have made it possible to acquire the information necessary for resolving the main problem arising during irradiation - the formation of coagulum. The first two cell are designed for irradiation by a horizontal beam ('Dynamitron'), the two others use a vertical beam ('Circe'). The study of the properties of the rubber obtained shows it to compare favorably with 'Revultex'. In the appendix are given some characteristics of natural latex and information about its processing. (authors) [French] Apres un rappel des principales etudes sur la radio-vulcanisation du latex et des elastomeres, on decrit les quatre types de cellules successivement essayes en vue de l'irradiation industrielle. Ils ont permis d'acquerir les informations necessaires a la resolution du probleme principal pose par l'irradiation, la formation de coagulum au cours de celle,-ci. Les deux premiers sont concus pour l'irradiation par un faisceau horizontal ('Dynamitron'), les derniers par un faisceau vertical ('Circe'). L'etude des proprietes du caoutchouc obtenu montre qu'il se compare favorablement au 'Revultex'. Un apercu est donne en annexe des caracteristiques du latex naturel et de sa mise en oeuvre. (auteurs)

  3. The development of a very high stability electrostatic generator (1962); Etude et realisation d'un generateur electrostatique a tres haute stabilite (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-07-01

    This thesis deals with the study of an electrostatic high voltage generator having a voltage stability of the order of 10{sup -6} per minute. This equipment should be very useful in electron microscopy. The electrostatic generator is studied as a control system element: transfer function, parasitic signals and noise are determined and a mathematical model is proposed. A theoretical study of the open loop transfer function, stability, transient response, voltage stabilization of five different control systems shows which one should be able to fulfill the requirements There follows a detailed study of drift, a description of the actual system and performance data. (author) [French] Cette etude concerne un generateur electrostatique capable de fournir une tres haute tension continue dont la stabilite relative est de l'ordre de 10{sup -6} pendant une minute. Une telle performance rend cet appareillage tres utile en microscopie electronique. La generatrice electrostatique est etudiee en tant qu'element d'un systeme asservi: on determine successivement la fonction de transfert, les perturbations, le bruit de fond et le modele mathematique. L'etude de cinq differents circuits de regulation en ce qui concerne leur fonction de transfert, stabilite, reponse en regime transitoire, attenuation des perturbations, permettra de choisir le systeme qui semble le mieux repondre aux exigences. Viennent ensuite une etude detaillee de la derive, la description de la realisation pratique et les resultats de mesure. (auteur)

  4. The development of a very high stability electrostatic generator (1962); Etude et realisation d'un generateur electrostatique a tres haute stabilite (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-07-01

    This thesis deals with the study of an electrostatic high voltage generator having a voltage stability of the order of 10{sup -6} per minute. This equipment should be very useful in electron microscopy. The electrostatic generator is studied as a control system element: transfer function, parasitic signals and noise are determined and a mathematical model is proposed. A theoretical study of the open loop transfer function, stability, transient response, voltage stabilization of five different control systems shows which one should be able to fulfill the requirements There follows a detailed study of drift, a description of the actual system and performance data. (author) [French] Cette etude concerne un generateur electrostatique capable de fournir une tres haute tension continue dont la stabilite relative est de l'ordre de 10{sup -6} pendant une minute. Une telle performance rend cet appareillage tres utile en microscopie electronique. La generatrice electrostatique est etudiee en tant qu'element d'un systeme asservi: on determine successivement la fonction de transfert, les perturbations, le bruit de fond et le modele mathematique. L'etude de cinq differents circuits de regulation en ce qui concerne leur fonction de transfert, stabilite, reponse en regime transitoire, attenuation des perturbations, permettra de choisir le systeme qui semble le mieux repondre aux exigences. Viennent ensuite une etude detaillee de la derive, la description de la realisation pratique et les resultats de mesure. (auteur)

  5. Development and testing of the EDF-2 reactor fuel element; Essais et mise au point de l'element combustible pour le reacteur EDF-2

    Energy Technology Data Exchange (ETDEWEB)

    Delpeyroux, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Furhmann, R [Societe Industrielle de Combustible Nucleaire (France)

    1964-07-01

    rassemble les etudes qui ont ete necessaires pour mener a bien la definition de l'element combustible EdF 2. Apres un bref rappel des caracteristiques du reacteur EdF 2 et des options preliminaires ayant permis de fixer un avant-projet d'element combustible, on aborde les etudes proprement dites: - Etudes uranium: essais de passage d'une couronne interne du tube en phase {beta}, flechage du tube sous l'action d'une force concentree, soudage des pastilles d'extremites et verification de leur etancheite. La tenue du tube a l'ecrasement et la resistance des pastilles a l'enfoncement sous l'action de la pression externe sont etudiees en detail dans un autre rapport CEA - Etudes gaine: rappel des conditions de fabrication et verification de l'etancheite de la gaine, tenue des ailettes au fluage sous l'action du courant gazeux - Etudes d'extremites: fluage en compression et soudage des bouchons a la gaine. - Etudes cartouche: determination des caracteristiques des gorges d'ancrage gaine-combustible et des conditions de gainage, verification de la tenue au cyclage thermique de l'element combustible, determination de la chute de temperature au contact gaine-combustible traitee en detail dans un autre rapport CEA, - Etudes de l'ensemble: les etudes se rapportant a la chemise de graphite, au support et aux vibrations de la cartouche ont ete traitees par le service des Etudes Mecaniques et Thermiques (Section de Mecanique), Dans ce domaine, la Section d'Etude d'Elements Combustibles a etudie la tenue des centreurs sous l'action du courant gazeux. L'aboutissement des etudes est constitue par le dessin de l'element combustible, le schema de fabrication et les normes de fabrication. La validite de l'ensemble de ces essais hors pile sera confirmee par des assais en pile qui sont en cours et par l'irradiation des elements dans le reacteur EdF 2 lui-meme. En conclusion, on donne l'orientation des etudes pour l'amelioration de l'element combustible et la definition d'un element combustible

  6. The use radioactive tracers in the study of solid transport in water streams; Emploi de traceurs radioactifs pour l'etude du transport solide dans les cours d'eau

    Energy Technology Data Exchange (ETDEWEB)

    Courtois, G [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Jaffry, P; Heuzel, M [Laboratoire National d' Hydraulique de Chatou, 78 (France)

    1960-07-01

    The Laboratoire National d'Hydraulique which has been studying, during the last few years in conjunction with the Centre d'Etudes Nucleaires at Saclay, the development of apparatus and of methods of investigation of sediment transport by radioactive tracer techniques, is at the moment trying to perfect a genuinely quantitative method of investigation. Two experiments have recently been carried out in rivers, the first designed to investigate the transport of pebbles in the river Rhone, the other to investigate the movement of sands in the Niger. This second experiment has been supported by parallel experiments carried out on a reduced scale model of the Niger built at the laboratories of Chatou: in this experiment are used the radiation from {sup 56}Mn and {sup 24}Na obtained by direct activation of the crushed apricot store which represents, in the scale model, the natural sediment on the bed of the Niger. The combined efforts of the laboratories of Chatou and of the Centre d'Etudes Nucleaires at Saclay are at the moment directed to the application of radioactive tracers to studies on the scale models with the double aim: a) of having a single investigational method for the actual experiment and for the model making it possible to control the accuracy of the model in the preliminary stage of calibrating this model; b) of making the most of the possibilities of observation and of direct measurement offered by the scale models for studying the possibility of improving the tracer method, in particular with respect to the collecting of quantitative data. (author) [French] La Laboratoire National d'Hydraulique qui, depuis quelques annees a developpe, en collaboration avec le Centre d'Etudes Nucleaires de Saclay, les appareillages et les techniques d'etudes des mouvements de sediments par la methode des traceurs radioactifs, s'efforce actuellement de mettre au point un moyen d'investigation veritablement quantitatif. Deux experiences ont ete effectuees recemment en

  7. Physical study of the 'snow flake' version of the reactor EL-3 (1963); Etude physique de la version ''cristal de neige'' de la pile EL-3 (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

    A systematic study has been made of the different thermodynamic and neutronic aspects of various versions of the 'snow flake' likely to fulfil the aims which were set out (improvement of the reactivity, of the experimental volume, improvement in the working conditions of EL-3). After this systematic study, a choice was made in principle of one version amongst the several available (solutions using 8 or 10 pencils-various methods of heat transfer: corrugation, cartridges which may or may not be filled with helium... etc., variable enrichments... ). The choice is that of a version which can already at the present be considered as feasible, which represents already a notable improvement of the pile and which does not imply the existence of a major problem as far as the possible change-over later to an improved version is concerned. This choice defines a fuel element and a configuration for the core. A detailed recapitulation has been made of all the research being carried out for the possible solutions in this particular case. (authors) [French] On a etudie systematiquement les differents aspects thermodynamiques et neutroniques de diverses versions 'cristal de neige' susceptibles de remplir les buts fixes (amelioration en reactivite, en volume experimental, amelioration des problemes d'exploitation de EL-3). Apres cette etude systematique, on a procede au choix de principe d'une version parmi les differentes solutions possibles (solutions a 8 ou 10 crayons - possibilite de transfert de chaleur divers: corrugations, cartouches remplies He ou non.... etc., enrichissements variables... ). Ce choix est celui d'une version qu'on peut juger viable des aujourd'hui, qui represente deja une amelioration importante de la pile et qui n'implique pas de probleme majeur quant au passage ulterieur et eventuel a une version plus amelioree. Ce choix definit un element combustible, et une configuration de coeur. On a recapitule et detaille sur ce cas particulier de pile les etudes

  8. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    nombre de ramification à 1 cm de l'apex) montre, une hétérogénéité de la population, ce qui confirmerait la forte ... Salinas [8] a mis au point une méthode de réensemencement basée sur l'initiation, en conditions ... sesquipedale, l'étude de son cycle de reproduction et la compréhension de la biologie de l'espèce dans son ...

  9. ETUDE DE LA DISTRIBUTION DES CATIONS ECHANGEABLES

    African Journals Online (AJOL)

    SEI Joseph

    structures à base de matériaux cimentaires lorsqu'elles sont soumises au séchage ainsi que leur influence sur les propriétés ... Mots-clés : matériaux cimentaires, béton, mortier, séchage, hétérogénéités, propriétés mécaniques. Abstract .... d'isolation thermique comparés aux moules en acier ou en bois. Dans ce cas, les ...

  10. Strata-bound Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho Cobalt Belt: Multistage hydrothermal mineralization in a magmatic-related iron oxide copper-gold system

    Science.gov (United States)

    Slack, John F.

    2012-01-01

    , consistent with the general lack of abundant chalcopyrite in cobaltite-rich samples.Paragenetic relations determined by scanning electron microscopy indicate that the earliest Y-REE-Be mineralization preceded deposition of Co, Cu, Au, and Bi. Allanite, xenotime, and gadolinite-(Y) commonly occur as intergrowths with and inclusions in cobaltite; the opposite texture is rare. Monazite, in contrast, forms a poikiloblastic matrix to cobaltite and thin rims on allanite and xenotime, reflecting a later metamorphic paragenesis. Allanite and xenotime also show evidence of late dissolution and reprecipitation, forming discordant rims on older anhedral allanite and xenotime and separate euhedral crystals of each mineral. Textural data suggest extensive deformation of the deposits by folding and shearing, and by pervasive recrystallization, all during Cretaceous metamorphism. Sensitive high resolution ion microprobe U-Pb geochronology by Aleinikoff et al. (2012) supports these paragenetic interpretations, documenting contemporaneous Mesoproterozoic growth of early xenotime and crystallization of megacrystic A-type granite on the northern border of the district. These ages are used together with mineralogical and geochemical data from the present study to support an epigenetic, IOCG model for Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho cobalt belt. A sulfide facies variant of IOCG deposits is proposed for the Blackbird district, in which reducing hydrothermal conditions favored deposition of sulfide minerals over iron oxides. This new model includes Mesoproterozoic vein mineralization and related Fe-Cl metasomatism that formed the biotite-rich lenses, a predominantly felsic magmatic source for metals in the deposits, given their local abundance of Y, REEs, and Be, and a major sedimentary component in the hydrothermal fluids based on independent sulfur isotope and boron isotope data for sulfides and ore-related tourmaline, respectively.

  11. N.3201 National Assembly law project relative to the energy sector; N.3201 Assemblee Nationale projet de loi relatif au secteur de l'energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This law text, elaborated in the framework of the energy market deregulation, presents the market deregulation and the free choice for the consumers, the dispositions relative to the gas and electric power distribution, the dispositions relative to the Gaz de France capital and the State control and dispositions relatives to contracts of natural ags and electric power supply. (A.L.B.)

  12. Radioautography in the Study of Radioisotopically-Tagged Substances in Insect Control; L'autoradiographie dans l'etude de substances marquees au moy en de radioisotopes utilisees dans la lutte contre les insectes; Primenenie radioavtografii pri izuchenii substantsij, mechennykh radioizotopami, v bor'be s nasekomymi; La autorradiografia en el estudio de las sustancias marcadas con radioisotopos utilizadas en la lucha contra los insectos

    Energy Technology Data Exchange (ETDEWEB)

    Joftes, D. L. [New England Deaconess Hospital, Boston, MA (United States)

    1963-09-15

    In return for a relatively small expenditure of effort, the newer, simplified techniques of radioautography offer great sensitivity and precision at the microscopic level in many phases of the investigations of singly or doubly radioisotopically-tagged insecticides: e.g., uptake, translocation, metabolism and determination of residues in insects, plants and animals. The physiology and biochemistry of irradiated Insects are other phases which can be studied by radioautography. Radiation effects on the generative organs, especially, are being studied with tritiated thymidine. Whereas counting techniques yield gross information on the presence and quantity of radioisotopes, radioautography can provide information on actual sites of deposition in tissues or even parts of cells. This resolution is available on ordinary permanent histological preparations, in contrast to counting techniques in which accuracy of counting demands the destruction of the sample. Standard radioautography is especially useful for conveniently following fractional microcurie amounts of very weak emitters such as radiocarbon (C{sup 14)} and tritium (H{sup 3}), as opposed to the very expensive, highly sophisticated apparatus which is required for counting techniques when very weak emitters are employed. The technique places no restriction on the isotope used for labelling, since even the radiation from tritium and C{sup 14} will register on the nuclear emulsion. In fact, tritium and C{sup 14} (which are desirable since nearly every insecticide will contain carbon and hydrogen) have the advantage of yielding high-resolution radioautograms and have long half-lives, so that if very long exposure times are necessary, there would be no difficulty. Long exposure times may be required since only tiny amounts of radioactivity, even of high-specific-activity insecticides, can be expected to be taken up. It is necessary to be certain that the insecticides are tagged at such a point in the molecule that the

  13. Study of the diffusion in the {alpha} brasses, using the evaporation or condensation of zinc - influence of the diffusion sense and of impurities (first and second thesis); Etude de la diffusion dans les laitons {alpha} au moyen des methodes d'evaporation ou de condensation du zinc influence du sens de diffusion et de la presence d'impurete (premiere et deuxieme these)

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-12-15

    The author develops a zero concentration extrapolation method for the exact determination of the diffusion coefficient. He applies it to the comparison of the inward and outward diffusion coefficient in {alpha} brasses. In a second part he shows the large influence of traces of some elements such as P, As, Sb, on the diffusion velocity in {alpha} brasses. (author) [French] L'auteur montre comment, au moyen d'une extrapolation a variation de concentration nulle, ces methodes permettent d'atteindre rigoureusement la valeur du coefficient de diffusion. Il les utilise pour comparer la valeur du coefficient de diffusion avec enrichissement en zinc a la valeur du coefficient de diffusion avec appauvrissement en zinc. Dans une seconde partie, il met en evidence la grande influence de traces d'elements tels que le phosphore, l'arsenic, l'antimoine sur la vitesse de diffusion dans les laitons {alpha}. (auteur)

  14. Electrochemical study in the molten sodium acid sulphate - potassium acid sulphate eutectic; Etude electrochimique dans l'eutectique fondu sulfate acide de sodium - sulfate acide de potassium

    Energy Technology Data Exchange (ETDEWEB)

    Le Ber, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    protons de HSO{sup -}{sub 4}. Nous avons compare les domaines d'electroactivite obtenus a differentes electrodes (Ag-Au-Graphite-Hg). Nous avons envisage la dissolution de quelques oxydes et halogenures metalliques. Cette etude montre le role des ions HSO{sup -}{sub 4} en tant qu'accepteurs d'ions O{sup 2-}. Nous avons entrepris l'etude electrochimique de quelques systemes oxydo-reducteurs: H{sup +} / H{sub 2}, Ag{down_arrow} / Ag (I), les systemes du vanadium et de l'uranium, du mercure Hg{down_arrow} / Hg{sup 2-}{sub 2} et de l'or Au/Au{sup 3+}; puis l'attaque par le solvant de quelques metaux usuels comme l'aluminium, le fer, le cuivre et le nickel. L'etude des systemes de l'argent nous a permis d'atteindre les produits de solubilite de AgCl et AgBr et d'envisager le titrage coulometrique des ions Cl{sup -} par des ions Ag{sup +}. Nous avons mis en evidence differentes especes chimiques du vanadium pouvant exister dans l'eutectique fondu. (auteur)

  15. No. 614 law project relative to the energy sector; No. 614 projet de Loi relatif au secteur de l'energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-11-15

    This law project concerns the market opening and the free choice of the consumers, the dispositions relative to the electricity and gas distribution and the dispositions relative to the Gaz De France capital and the government control. (A.L.B.)

  16. Mise au point

    African Journals Online (AJOL)

    tomie est replacé et fixé par des fils d'acier, krönlein lais- sait ce fragment pédiculé au fascia temporalis afin d'évi- ter la dépression de la fosse temporale due à la désinser- tion du muscle temporal [20] ; dans notre série, après reconstitution du cadre, le muscle temporal est suturé à son point d'insertion. pour les tumeurs ...

  17. Antibacterial Au nanostructured surfaces

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all

  18. Au pairs on Facebook

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2016-01-01

    Ethnographers are increasingly making use of Facebook to acquire access and general acquaintance with their field of study. However, little has been written on how Facebook is used methodologically in research that does not have social media sites as the main focus of interest. This article argues...... the au pairs resist and embrace such dominant representations, and on how such representations are ascribed different meanings in the transnational social fields of which the migrant are a part. The article is based on ethnographic fieldwork conducted between 2010 and 2014 in Denmark, the Philippines...

  19. 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)

  20. Study of the point defects formed in cobalt by electron bombardment; Etude des defauts ponctuels crees par bombardement electronique dans le cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Sulpice, G [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1968-12-01

    A study of the point defects formed in cobalt by electron bombardment is presented. The results are compared with those previously obtained for two other ferromagnetic metals of different structure, iron and nickel. In the first part we give a review of the literature concerning the creation of point defects, their contribution to resistivity and their annihilation mode in the three structure types. We then describe the experimental techniques adapted, in particular the study of the resistivity increase during a linear temperature rise. Our investigations concern the following, essential points : the observation of the successive annihilation stages of the point defects formed in pure cobalt, a study of the variations with respect to the doses and energy of the incident particles, and the determination of the annealing kinetics and the corresponding activation energies. The results are finally compared with the various models of point defect annihilation proposed for other metals: none of these interpretations is in perfect agreement with our results. In the case of cobalt we are thus led to modify the model proposed by our laboratory for iron an nickel. The difference between these three metals is explained by the anisotropic character of the cobalt matrix. (author) [French] Nous presentons une etude des defauts ponctuels crees par bombardement electronique dans le cobalt et comparons nos resultats a ceux obtenus precedemment dans deux autres metaux ferromagnetiques de structure differente, le fer et le nickel. Dans une premiere partie nous faisons une mise au point bibliographique comparee sur la creation des defauts, leur contribution a la resistivite et leur mode d'annihilation dans les trois types de structure. Nous decrivons ensuite les techniques experimentales mises au point, en particulier l'etude du revenu de la resistivite au cours d'une montee lineaire de temperature. Au cours de ce travail, nous avons mis en evidence les stades successifs d

  1. Antibacterial Au nanostructured surfaces.

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-02-07

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.

  2. On the interactions between carbon monoxide and transition metals; Contribution a l'etude des interractions de l'oxyde de carbone et des metaux de transition

    Energy Technology Data Exchange (ETDEWEB)

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

    1966-12-01

    The sticking of carbon monoxide on surface atoms of transition metals is a collective phenomenon: according to the adsorption process period which is considered, this phenomenon may be formally described either by the Elovich equation or essentially from a steric point of view. The process rate depends upon the nature of the metal, the carbon monoxide pressure the temperature and the population densities of the induced and fundamental energy levels of the gas-solid bond. At least one of these induced levels tends to disappear with increasing time. For a localised adsorption and taking into account the surface Rayleigh waves, the analysis of the surface entropy yields the so-called iso-kinetic temperature for thermal desorption. This temperature is correlated with the cohesive energy of the metal surface atoms. Finally, it is shown that the interactions of a low energy electron bean with adsorbed molecules - reflection and energy exchange, desorption, ionization or dissociative ionization are strongly dependent on the energy levels of the gas-solid bond and the relative populations of these levels. (author) [French] La capture des molecules d'oxyde de carbone par les atomes de surface des metaux de transition est un phenomene collectif: il peut etre decrit formellernent soit par l'equation d'Elovich, soit a partir de considerations purement steriques suivant la periode envisagee dans l'evolution du processus d'adsorption. Cette evolution est determinee par la nature du metal, la pression d'oxyde de carbone, la temperature et la densite des populations des niveaux fondamental et induits de la liaison. L'un au moins de ceux-ci tend a disparaitre avec le temps. L' etude de l'entropie du complexe de surface a partir des ondes de Rayleigh en adsorption localisee permet de retrouver theoriquernent la temperature dite isocinetique dans la dissociation thermique de ce complexe. Cette temperature depend de la cohesion des atomes rnetalliques de surface. Enfin l'interaction d

  3. Processing radioactive effluents with ion-exchanging resins: study of result extrapolation; Traitement des effluents radioactifs par resines echangeuses d'ions: etude de l'extrapolation des resultats

    Energy Technology Data Exchange (ETDEWEB)

    Wormser, G.

    1960-05-03

    As a previous study showed the ion-exchanging resins could be used in Saclay for the treatment of radioactive effluents, the author reports a study which aimed at investigating to which extent thus obtained results could be extrapolated to the case of higher industrial columns. The author reports experiments which aimed at determining extrapolation modes which could be used for columns of organic resin used for radioactive effluent decontamination. He notably studied whether the Hiester and Vermeulen extrapolation law could be applied. Experiments are performed at constant percolation flow rate, at varying flow rate, and at constant flow rate [French] Plusieurs etudes ont ete faites dans le but d'examiner les possibilites d'emploi des resines echangeuses d'ions pour le traitement des effluents radioactifs. Dans un rapport preliminaire, nous avons montre dans quelles limites un tel procede pouvait etre utilise au Centre d'Etudes Nucleaires de Saclay. Les essais ont ete effectues sur des petites colonnes de resine au laboratoire; il est apparu ensuite necessaire de prevoir dans quelle mesure les resultats ainsi obtenus peuvent etre extrapoles a des colonnes industrielles, de plus grande hauteur. Les experiences dont les resultats sont exposes dans ce rapport, ont pour but de determiner les modes d'extrapolation qui pourraient etre employes pour des colonnes de resine organique utilisees pour la decontamination d'effluents radioactifs. Nous avons en particulier recherche si la loi d'extrapolation de Hiester et Vermeulen qui donne de bons resultats dans le cas de fixation d'ions radioactifs en presence d'un ion macrocomposant sur des terres, pouvait etre appliquee. Les experiences, en nombre limite, ont montre que la loi d'extrapolation de Hiester et Vermeulen pouvait s'appliquer dans le cas de l'effluent considere quand les debits de percolation sont tres faibles; quand ils sont plus forts, les volumes de liquide percoles, a fixation egale, sont proportionnels aux

  4. Cluster-to-cluster transformation among Au6, Au8 and Au11 nanoclusters.

    Science.gov (United States)

    Ren, Xiuqing; Fu, Junhong; Lin, Xinzhang; Fu, Xuemei; Yan, Jinghui; Wu, Ren'an; Liu, Chao; Huang, Jiahui

    2018-05-22

    We present the cluster-to-cluster transformations among three gold nanoclusters, [Au6(dppp)4]2+ (Au6), [Au8(dppp)4Cl2]2+ (Au8) and [Au11(dppp)5]3+ (Au11). The conversion process follows a rule that states that the transformation of a small cluster to a large cluster is achieved through an oxidation process with an oxidizing agent (H2O2) or with heating, while the conversion of a large cluster to a small one occurs through a reduction process with a reducing agent (NaBH4). All the reactions were monitored using UV-Vis spectroscopy and ESI-MS. This work may provide an alternative approach to the synthesis of novel gold nanoclusters and a further understanding of the structural transformation relationship of gold nanoclusters.

  5. Charged particle density distributions in Au + Au collisions at ...

    Indian Academy of Sciences (India)

    Charged particle pseudorapidity distributions have been measured in Au + Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of the collision centrality and the center of mass energy. They are compared to the predictions of different parton scattering models and the important role of ...

  6. Pleural mesothelioma: dose-response relation at low levels of asbestos exposure in a french population-based case-control study; Mesotheliome pleural: relation dose-reponse a faibles niveaux d'exposition a l'amiante dans une etude cas-temoins au sein d'une polulation francaise

    Energy Technology Data Exchange (ETDEWEB)

    Iwatsubo, Y.; Pairo, J.C.; Boutin, C.; Menard, O.; Massin, N.; Caillaud, D.; Orlowski, E.; Galateau-Salle, F.; Bignon, J.; Brochard, P.

    1998-03-01

    The objectives of this study were to study the dose-response relationship between professional exposure to asbestos and the supervening of the pleural mesothelioma in general population. This work notes an excess of death by pulmonary cancer among the asbestos-cement workers but one can regret the weakness of the exposure estimation (only one source of exposure is considered) and that some others risk factors have not been taken into account (tobacco, for example). (N.C.)

  7. TiAu based shape memory alloys for high temperature applications

    International Nuclear Information System (INIS)

    Wadood, Abdul; Yamabe-Mitarai, Yoko; Hosoda, Hideki

    2014-01-01

    TiAu (equiatomic) exhibits phase transformaion from B2 (ordered bcc) to thermo-elastic orthorhombic B19 martensite at about 875K and thus TiAu is categorized as high temperature shape memory alloy. In this study, recent research and developments related to TiAu based high temperature shape memory alloys will be discussed in the Introduction part. Then some results of our research group related to strengthening of TiAu based high temperature shape memory alloys will be presented. Potential of TiAu based shape memory alloys for high temperature shape memory materials applications will also be discussed

  8. La mise en œuvre des règles internationales relatives à la protection des personnes vulnérables au Cameroun

    NARCIS (Netherlands)

    Koukolo Koukolo, Germain

    2016-01-01

    The topic of this research is: The Implementation of International Rules related to the Protection of Vulnerable Persons in Cameroon. Implementation is one most topical issues with respect to Human Rights in developing countries. States have adopted international rules concerning vulnerable persons,

  9. An SFG and DFG investigation of polycrystalline Au, Au-Cu and Au-Ag-Cu electrodes in contact with aqueous solutions containing KCN

    International Nuclear Information System (INIS)

    Bozzini, Benedetto; Busson, Bertrand; De Gaudenzi, Gian Pietro; Mele, Claudio; Tadjeddine, Abderrahmane

    2007-01-01

    In this paper, the behaviour of polycrystalline Au, Au-Cu (Cu 25%) and Au-Ag-Cu (Ag 10%, Cu 15%) electrodes in contact with neutral aqueous solutions of KCN has been studied as a function of potential by means of in situ sum frequency generation (SFG) and difference frequency generation (DFG) spectroscopies. The potential-dependent spectra have been analysed quantitatively with a model for the second-order non-linear susceptibility accounting for vibrational and electronic effects. The potential-dependence of the CN - stretching band position and of the free-electron contribution to the real part of the non-resonant component of the second-order susceptibility have been accounted for. Spectroelectrochemical results were complemented by cyclic voltammetric measurements. The chief stress in this work has been placed on systematising and quantifying the interaction between the vibrational and electronic structures of the electrodic interfaces studied. The effects of adsorbates on the electronic structure of the adsorbing electrode, as a function of electrode alloy composition and applied potential are particularly critical for the understanding of Au-alloy electrochemistry in the presence of cyanide and cyanocomplexes. The systematic comparison of SFG and DFG spectra measured under the same electrochemical conditions for Au, Au-Cu and Au-Ag-Cu electrodes discloses a rich phenomenology related to the electronic structure of the interface

  10. An SFG and DFG investigation of polycrystalline Au, Au-Cu and Au-Ag-Cu electrodes in contact with aqueous solutions containing KCN

    Energy Technology Data Exchange (ETDEWEB)

    Bozzini, Benedetto [Dipartimento di Ingegneria dell' Innovazione, Universita di Lecce, v. Monteroni, I-73100 Lecce (Italy)]. E-mail: benedetto.bozzini@unile.it; Busson, Bertrand [CLIO-LCP, Universite Paris-Sud, 91405 Orsay Cedex (France); De Gaudenzi, Gian Pietro [Dipartimento di Ingegneria dell' Innovazione, Universita di Lecce, v. Monteroni, I-73100 Lecce (Italy); Mele, Claudio [Dipartimento di Ingegneria dell' Innovazione, Universita di Lecce, v. Monteroni, I-73100 Lecce (Italy); Tadjeddine, Abderrahmane [UDIL-CNRS, Bat. 201, Centre Universitaire Paris-Sud, BP 34, 91898 Orsay Cedex (France)

    2007-01-16

    In this paper, the behaviour of polycrystalline Au, Au-Cu (Cu 25%) and Au-Ag-Cu (Ag 10%, Cu 15%) electrodes in contact with neutral aqueous solutions of KCN has been studied as a function of potential by means of in situ sum frequency generation (SFG) and difference frequency generation (DFG) spectroscopies. The potential-dependent spectra have been analysed quantitatively with a model for the second-order non-linear susceptibility accounting for vibrational and electronic effects. The potential-dependence of the CN{sup -} stretching band position and of the free-electron contribution to the real part of the non-resonant component of the second-order susceptibility have been accounted for. Spectroelectrochemical results were complemented by cyclic voltammetric measurements. The chief stress in this work has been placed on systematising and quantifying the interaction between the vibrational and electronic structures of the electrodic interfaces studied. The effects of adsorbates on the electronic structure of the adsorbing electrode, as a function of electrode alloy composition and applied potential are particularly critical for the understanding of Au-alloy electrochemistry in the presence of cyanide and cyanocomplexes. The systematic comparison of SFG and DFG spectra measured under the same electrochemical conditions for Au, Au-Cu and Au-Ag-Cu electrodes discloses a rich phenomenology related to the electronic structure of the interface.

  11. {phi} meson production in Au + Au and p + p collisions at {radical}s{sub NN}=200 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G.S.; Badyal, S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj, S.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Carroll, J.; Castillo, J.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Ganti, M.S.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grebenyuk, O.; Gronstal, S.; Grosnick, D.; Guedon, M.; Guertin, S.M.; Gupta, A.; Gutierrez, T.D.; Hallman, T.J.; Hamed, A.; Hardtke, D.; Harris, J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang, S.L.; Hughes, E.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaplan, M.; Keane, D.; Khodyrev; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Kopytine, S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Kravstov, V.I.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.Kh.; et al.

    2004-06-01

    We report the STAR measurement of {psi} meson production in Au + Au and p + p collisions at {radical}s{sub NN} = 200 GeV. Using the event mixing technique, the {psi} spectra and yields are obtained at midrapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the {psi} transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that {psi} production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions (). The systematics of versus centrality and the constant {psi}/K{sup -} ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for {psi} production.

  12. Lombalgies chroniques : évaluation des facteurs mécaniques des membres inférieurs au moyen des relations moment-vitesse

    OpenAIRE

    Lemaire , Alexandra

    2014-01-01

    Low back pain is a public health problem inducing economical and social consequences. Chronicity involves less than 10% of low back pain, but represents 85% of the total costs related to this pathology. In this context, it seems essential to optimize chronic low back pain rehabilitation programs to make them more effective and relevant. The purpose of this phD was then to evaluate lower limbs mechanical factors using torque- and power-velocity relationships. In a first study, knee extensors m...

  13. La structure sociale de l’industrie des Biotechnologies en France: une étude des relations inter-organisationnelles au niveau inter-individuel.

    Directory of Open Access Journals (Sweden)

    Piña-Stranger, Alvaro

    2010-06-01

    Full Text Available Various authors have shown the importance of collaborative relationships for inter-organizational performance, the mode of governance or the trajectory of biotechnology companies. Most of these works analyze the exclusive contractual agreements between companies and their main relationships among individuals. We show that this purely economic approach presents a major limitation: the nature of contractual relationships does not explore in detail how players cooperate. We propose to extend the study of these inter-organizational social relations, seen through the resource exchange in inter-individual. An empirical study on the leaders of the biotechnology industry in the area of human health in France has allowed us to map their relationships and resources they exchange them. Our results confirm the existence of a system of exchange dense and multiple. It presents a hierarchical distribution of various types of resources, where the centre is different from the periphery relations denser, more numerous and more reciprocal. However, comparative analysis of different networks reveals that the relationships of the board are highly centralized, while those of friendship following a more even distribution. We suggest that this phenomenon is part of a compensation mechanism to less central actors to maintain inter-organizational relationships. Finally, two standards of the cooperation process, revealed by the relational behaviour of actors, have been discovered. We suggest that they reflect in part the difficult process of adjustment that must cross a science project out of the realm of academic research and develop in a private structure: the biotech company.

  14. Safety guidebook relative to the disposal of radioactive wastes in deep geologic formation; Guide de surete relatif au stockage definitif des dechets radioactifs en formation geologique profonde

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    The French nuclear safety authority (ASN) initiated in 2003 a revision process of the objectives to be considered during the research and work steps of the implementation of a radioactive waste storage facility in deep geologic formations. The purpose of this document is to define the safety objectives that have to be retained at each step of this implementation, from the site characterization to the closure of the facility. This update takes into account the works carried out by the ANDRA (French national agency of radioactive wastes) in the framework of the law from December 30, 1991, and the advices of the permanent experts group about these works. It takes also into consideration the international research works in this domain and the choices defined in the program law no 2006-739 from June 28, 2006 relative to the sustainable management of radioactive materials and wastes. The main modifications concern: the notion of reversibility, the definition of the safety functions of disposal components, the safety goals and the design principles assigned to waste packages, the control of nuclear materials and the monitoring objectives of the facility. The documents treats of the following points: 1 - the objectives of public health and environment protection; 2 - the safety principles and the safety-related design bases of the facility; and 3 - the method used for demonstrating the disposal safety. (J.S.)

  15. Elliptic Flow in Au+Au Collisions at √sNN = 130 GeV

    Science.gov (United States)

    Ackermann, K. H.; Adams, N.; Adler, C.; Ahammed, Z.; Ahmad, S.; Allgower, C.; Amsbaugh, J.; Anderson, M.; Anderssen, E.; Arnesen, H.; Arnold, L.; Averichev, G. S.; Baldwin, A.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Beddo, M.; Bekele, S.; Belaga, V. V.; Bellwied, R.; Bennett, S.; Bercovitz, J.; Berger, J.; Betts, W.; Bichsel, H.; Bieser, F.; Bland, L. C.; Bloomer, M.; Blyth, C. O.; Boehm, J.; Bonner, B. E.; Bonnet, D.; Bossingham, R.; Botlo, M.; Boucham, A.; Bouillo, N.; Bouvier, S.; Bradley, K.; Brady, F. P.; Braithwaite, E. S.; Braithwaite, W.; Brandin, A.; Brown, R. L.; Brugalette, G.; Byrd, C.; Caines, H.; Calderón de La Barca Sánchez, M.; Cardenas, A.; Carr, L.; Carroll, J.; Castillo, J.; Caylor, B.; Cebra, D.; Chatopadhyay, S.; Chen, M. L.; Chen, W.; Chen, Y.; Chernenko, S. P.; Cherney, M.; Chikanian, A.; Choi, B.; Chrin, J.; Christie, W.; Coffin, J. P.; Conin, L.; Consiglio, C.; Cormier, T. M.; Cramer, J. G.; Crawford, H. J.; Danilov, V. I.; Dayton, D.; Demello, M.; Deng, W. S.; Derevschikov, A. A.; Dialinas, M.; Diaz, H.; Deyoung, P. A.; Didenko, L.; Dimassimo, D.; Dioguardi, J.; Dominik, W.; Drancourt, C.; Draper, J. E.; Dunin, V. B.; Dunlop, J. C.; Eckardt, V.; Edwards, W. R.; Efimov, L. G.; Eggert, T.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Etkin, A.; Fachini, P.; Feliciano, C.; Ferenc, D.; Ferguson, M. I.; Fessler, H.; Finch, E.; Fine, V.; Fisyak, Y.; Flierl, D.; Flores, I.; Foley, K. J.; Fritz, D.; Gagunashvili, N.; Gans, J.; Gazdzicki, M.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Gojak, C.; Grabski, J.; Grachov, O.; Grau, M.; Greiner, D.; Greiner, L.; Grigoriev, V.; Grosnick, D.; Gross, J.; Guilloux, G.; Gushin, E.; Hall, J.; Hallman, T. J.; Hardtke, D.; Harper, G.; Harris, J. W.; He, P.; Heffner, M.; Heppelmann, S.; Herston, T.; Hill, D.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G. W.; Horsley, M.; Howe, M.; Huang, H. Z.; Humanic, T. J.; Hümmler, H.; Hunt, W.; Hunter, J.; Igo, G. J.; Ishihara, A.; Ivanshin, Yu. I.; Jacobs, P.; Jacobs, W. W.; Jacobson, S.; Jared, R.; Jensen, P.; Johnson, I.; Jones, P. G.; Judd, E.; Kaneta, M.; Kaplan, M.; Keane, D.; Kenney, V. P.; Khodinov, A.; Klay, J.; Klein, S. R.; Klyachko, A.; Koehler, G.; Konstantinov, A. S.; Kormilitsyne, V.; Kotchenda, L.; Kotov, I.; Kovalenko, A. D.; Kramer, M.; Kravtsov, P.; Krueger, K.; Krupien, T.; Kuczewski, P.; Kuhn, C.; Kunde, G. J.; Kunz, C. L.; Kutuev, R. Kh.; Kuznetsov, A. A.; Lakehal-Ayat, L.; Lamas-Valverde, J.; Lamont, M. A.; Landgraf, J. M.; Lange, S.; Lansdell, C. P.; Lasiuk, B.; Laue, F.; Lebedev, A.; Lecompte, T.; Leonhardt, W. J.; Leontiev, V. M.; Leszczynski, P.; Levine, M. J.; Li, Q.; Li, Q.; Li, Z.; Liaw, C.-J.; Lin, J.; Lindenbaum, S. J.; Lindenstruth, V.; Lindstrom, P. J.; Lisa, M. A.; Liu, H.; Ljubicic, T.; Llope, W. J.; Locurto, G.; Long, H.; Longacre, R. S.; Lopez-Noriega, M.; Lopiano, D.; Love, W. A.; Lutz, J. R.; Lynn, D.; Madansky, L.; Maier, R.; Majka, R.; Maliszewski, A.; Margetis, S.; Marks, K.; Marstaller, R.; Martin, L.; Marx, J.; Matis, H. S.; Matulenko, Yu. A.; Matyushevski, E. A.; McParland, C.; McShane, T. S.; Meier, J.; Melnick, Yu.; Meschanin, A.; Middlekamp, P.; Mikhalin, N.; Miller, B.; Milosevich, Z.; Minaev, N. G.; Minor, B.; Mitchell, J.; Mogavero, E.; Moiseenko, V. A.; Moltz, D.; Moore, C. F.; Morozov, V.; Morse, R.; de Moura, M. M.; Munhoz, M. G.; Mutchler, G. S.; Nelson, J. M.; Nevski, P.; Ngo, T.; Nguyen, M.; Nguyen, T.; Nikitin, V. A.; Nogach, L. V.; Noggle, T.; Norman, B.; Nurushev, S. B.; Nussbaum, T.; Nystrand, J.; Odyniec, G.; Ogawa, A.; Ogilvie, C. A.; Olchanski, K.; Oldenburg, M.; Olson, D.; Ososkov, G. A.; Ott, G.; Padrazo, D.; Paic, G.; Pandey, S. U.; Panebratsev, Y.; Panitkin, S. Y.; Pavlinov, A. I.; Pawlak, T.; Pentia, M.; Perevotchikov, V.; Peryt, W.; Petrov, V. A.; Pinganaud, W.; Pirogov, S.; Platner, E.; Pluta, J.; Polk, I.; Porile, N.; Porter, J.; Poskanzer, A. M.; Potrebenikova, E.; Prindle, D.; Pruneau, C.; Puskar-Pasewicz, J.; Rai, G.; Rasson, J.; Ravel, O.; Ray, R. L.; Razin, S. V.; Reichhold, D.; Reid, J.; Renfordt, R. E.; Retiere, F.; Ridiger, A.; Riso, J.; Ritter, H. G.; Roberts, J. B.; Roehrich, D.; Rogachevski, O. V.; Romero, J. L.; Roy, C.; Russ, D.; Rykov, V.; Sakrejda, I.; Sanchez, R.; Sandler, Z.; Sandweiss, J.; Sappenfield, P.; Saulys, A. C.; Savin, I.; Schambach, J.; Scharenberg, R. P.; Scheblien, J.; Scheetz, R.; Schlueter, R.; Schmitz, N.; Schroeder, L. S.; Schulz, M.; Schüttauf, A.; Sedlmeir, J.; Seger, J.; Seliverstov, D.; Seyboth, J.; Seyboth, P.; Seymour, R.; Shakaliev, E. I.; Shestermanov, K. E.; Shi, Y.; Shimanskii, S. S.; Shuman, D.; Shvetcov, V. S.; Skoro, G.; Smirnov, N.; Smykov, L. P.; Snellings, R.; Solberg, K.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stephenson, E. J.; Stock, R.; Stolpovsky, A.; Stone, N.; Stone, R.; Strikhanov, M.; Stringfellow, B.; Stroebele, H.; Struck, C.; Suaide, A. A.; Sugarbaker, E.; Suire, C.; Symons, T. J.; Takahashi, J.; Tang, A. H.; Tarchini, A.; Tarzian, J.; Thomas, J. H.; Tikhomirov, V.; Szanto de Toledo, A.; Tonse, S.; Trainor, T.; Trentalange, S.; Tokarev, M.; Tonjes, M. B.; Trofimov, V.; Tsai, O.; Turner, K.; Ullrich, T.; Underwood, D. G.; Vakula, I.; van Buren, G.; Vandermolen, A. M.; Vanyashin, A.; Vasilevski, I. M.; Vasiliev, A. N.; Vigdor, S. E.; Visser, G.; Voloshin, S. A.; Vu, C.; Wang, F.; Ward, H.; Weerasundara, D.; Weidenbach, R.; Wells, R.; Wells, R.; Wenaus, T.; Westfall, G. D.; Whitfield, J. P.; Whitten, C.; Wieman, H.; Willson, R.; Wilson, K.; Wirth, J.; Wisdom, J.; Wissink, S. W.; Witt, R.; Wolf, J.; Wood, L.; Xu, N.; Xu, Z.; Yakutin, A. E.; Yamamoto, E.; Yang, J.; Yepes, P.; Yokosawa, A.; Yurevich, V. I.; Zanevski, Y. V.; Zhang, J.; Zhang, W. M.; Zhu, J.; Zimmerman, D.; Zoulkarneev, R.; Zubarev, A. N.

    2001-01-01

    Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sNN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

  16. Light Fragment Production and Power Law Behavior in Au + Au Collisions

    International Nuclear Information System (INIS)

    Wang, S.; Albergo, S.; Bieser, F.; Brady, F.P.; Caccia, Z.; Cebra, D.A.; Chacon, A.D.; Chance, J.L.; Choi, Y.; Costa, S.; Elliott, J.B.; Gilkes, M.L.; Hauger, J.A.; Hirsch, A.S.; Hjort, E.L.; Insolia, A.; Justice, M.; Keane, D.; Kintner, J.; Lisa, M.A.; Matis, H.S.; McMahan, M.; McParland, C.; Olson, D.L.; Partlan, M.D.; Porile, N.T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H.G.; Romanski, J.; Romero, J.L.; Russo, G.V.; Scharenberg, R.P.; Scott, A.; Shao, Y.; Srivastava, B.K.; Symons, T.J.M.; Tincknell, M.L.; Tuve, C.; Warren, P.G.; Weerasundara, D.; Wieman, H.H.; Wolf, K.L.

    1995-01-01

    Using charged-particle-exclusive measurements of Au+Au collisions in the LBL Bevalac's EOS time projection chamber, we investigate momentum-space densities of fragments up to 4 He as a function of fragment transverse momentum, azimuth relative to the reaction plane, rapidity, multiplicity, and beam energy. Most features of these densities above a transverse momentum threshold are consistent with momentum-space coalescence, and, in particular, the increase in sideward flow with fragment mass is generally well described by a momentum-space power law

  17. La relation entre les sources externes de connaissances, l’innovation organisationnelle et la performance organisationnelle : application au contexte tunisien

    Directory of Open Access Journals (Sweden)

    Rim Maâlej Ben Zaied

    2016-03-01

    Full Text Available Les entreprises d’aujourd’hui sont devenues plus intéressées à stimuler la connaissance, qui est considérée comme le principal atout. En conséquence, le concept de knowledge management attire une attention particulière et considérable. Cette recherche examine l’importance des sources externes de connaissances et sa relation avec l’innovation organisationnelle et la performance organisationnelle. Nous avons fait cette recherche sur un échantillon de 200 entreprises tunisiennes opérant dans différents secteurs. Notre étude a été construite principalement sur la base d’une méthode quantitative. La méthode de collecte de données est le questionnaire dans le cadre d’une approche hypothétique-déductive et le mode d’administration est l’enquête auto-administrée et l’e-mail. La vérification empirique des hypothèses de cette recherche nous a conduits à confirmer la relation entre, d’une part, les sources externes de connaissances et, d’autre part, la performance et l’innovation organisationnelles, et de confirmer aussi la relation entre l’innovation et la performance organisationnelle. Notre recherche de travail suggère un certain nombre de limitations : le fait que cette recherche repose en grande partie sur la perception des différents gestionnaires visés avec un voile, qui empêche plus de subjectivité, et la généralisation des résultats. Cela pourrait poser un certain biais puisque la plupart des données nécessaires pour mesurer les variables sont intangibles par nature, et il serait difficile, voire impossible, de les récupérer d’une manière objective.

  18. Preliminary Studies of the Field Movement of the Olive Fruit Fly (Dacus Oleae Gmel,) by Labelling a Natural Population with Radioactive Phosphorus (P{sup 32}); Etudes preijminaires sur les deplacements de la mouche de l'olive (Dacus Oleae Gmel. ) par marquage d'une population naturelle au radiophosphore ({sup 32}P); Predvaritel'noe issledovanie polevogo peremeshcheniya olivkovoj fruktovoj mukhi (Dacus Oleae Gmel.) posredstvom mecheniya estestvennoj populyatsii radioaktivnym fosforom (P{sup 32}).; Estudio preliminar de la dispersion de moscas del ouvo (Dacus Oleae Gmel. ) mediante la marcacion de poblaciones naturales con {sup 32}p.

    Energy Technology Data Exchange (ETDEWEB)

    Pelekassis, Constantine E.D.; Mourikos, P. A.; Bantzios, D. N. [Economic Entomology Laboratory, Benaki Phytopathological Institute, Athens (Greece)

    1963-09-15

    ) [French] Les auteurs ont procede a des experiences preliminaires pour recueillir des donnees de base sur les deplacements de la mouche de l'olive (Dacus oleae Gmel.). Ces etudes ont ete menees dans les oliveraies de Rovies, Evvia, en Grece, a l'automne 1961, a l'epoque ou les mouches adultes sont particulierement actives. Les auteurs ont prepare un melange de H{sub 3}-{sup 32}P-O{sub 4} dans HCl et d'hydrolysat de proteine, Staley no 7, pour marquer une population naturelle de mouches adultes. Une nourriture allechante a base de la solution marquee a ete appliquee le 14 octobre 1961 sur les branches de 30 oliviers choisis dans une oliveraie semimontagneuse, a Rovies. Les mouches ont ete capturees a l'aide de 500 pieges McPhail, contenant 3% de phosphate diammonique qui servait d'appat. Les pieges avaient ete repartis dans les oliveraies de Rovies ainsi que dans les zones adjacentes (forets ou oliveraies) dans un rayon de 10 km autour des arbres traites. Au total, 350 mouches marquees des deux sexes ont ete recueillies dans 48 pieges au cours de 15 releves effectues entre le 15 octobre et le 18 novembre. Les mouches marquees, qui ont ete capturees' de 1 a 35 jours apres le traitement, representaient 2,8% du nombre total des mouches recueillies dans les 48 pieges ou 0,15{sup %} du nombre total des mouches capturees dans 298 pieges dans toute la zone de Rovies; 73% des mouches marquees ont ete capturees dans les 10 premiers jours apres le traitement. On a trouve des mouches marquees jusqu'a 4300 m des arbres portant la solution marquee (maximum de dispersion). La radioactivite des mouches marquees etait comprise entre 258 et 9549 cpm par mouche (rayonnement ambiant, 8 a 21 cpm). Ces experiences preliminaires ont confirme l'existence d'un deplacement local plus ou moins continu (dispersion) des mouches entre l'oliveraie semi-montagneuse et les plaines adjacentes ou les oliveraies cotieres de Rovies, suivant une direction nord-sud. On n'a pas observe de deplacement a grande

  19. Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC.

    Science.gov (United States)

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2003-08-15

    We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.

  20. Contribution to the study of internal friction in graphites; Contribution a l'etude du frottement interieur des graphites

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-03-01

    A study has been made of the internal friction in different graphites between -180 C and +500 C using a torsion pendulum; the graphites had been previously treated thermo-mechanically, by neutron irradiation and subjected to partial annealings. It has been shown that there occurs: a hysteretic type dissipation of energy, connected with interactions between dislocations and other defects in the matrix; a dissipation having a partially hysteretic character which can be interpreted by a Granato-Luke type formalism and which is connected with the presence of an 'ultra-micro porosity'; a dissipation by a relaxation mechanism after a small dose of irradiation; this is attributed to the reorientation of bi-interstitials; a dissipation having the characteristics of a solid state transformation, this during an annealing after irradiation. It is attributed to the reorganization of interstitial defects. Some information has thus been obtained concerning graphites, in particular: their behaviour at low mechanical stresses, the nature of irradiation defects and their behaviour during annealing, the structural changes occurring during graphitization, the relationship between internal friction and macroscopic mechanical properties. (author) [French] L'etude du coefficient de frottement interieur au moyen d'un pendule de torsion entre -180 C et +500 C a ete realisee pour differents graphites apres des traitements thermo-mecaniques, des irradiations neutroniques et des guerisons partielles. Il a ete mis en evidence: une dissipation d'energie a caractere hysteretique, reliee aux interactions des dislocations avec les autres defauts de la matrice; une dissipation a caractere partiellement hysteretique, interpretable par un formalisme type Granato-Lucke et reliee a la presence d'une ''ultra-microporosite''; une dissipation par un mecanisme de relaxation, apres irradiation a faible dose, attribuee a la reorientation de di-interstitiels; une dissipation presentant les caracteristiques d

  1. Recommandations essentielles de sécurité relatives au travail du personnel des laboratoires géologiques de chantier Essential Safety Recommendations Concerning Work by Personnel in Well Site Mud Logging Units

    Directory of Open Access Journals (Sweden)

    Chambre Syndicale du Pétrole

    2006-11-01

    Full Text Available Le personnel travaillant dans les cabines géologiques sur chantiers de forage doit respecter des règles de sécurité pour la prévention des accidents et doit connaître nécessairement les consignes à suivre en cas de danger. Ces recommandations sont relatives à l'installation des cabines géologiques et aux problèmes créés par leur équipement très diversifié, comprenant notamment de nombreux capteurs dispersés sur le chantier et leur réseau de câbles de liaison. Huit annexes rappellent les risques inhérents à la présence d'hydrogène sulfuré et les conditions d'utilisation des appareils de protection, les problèmes liés aux fours à micro-ondes éventuellement installés, ceux liés à la présence de sources radioactives. Une large part de ces recommandations est consacrée au stockage, à la manipulation et à l'élimination des produits chimiques couramment présents dans les cabines. Dix-neuf fiches de prévention simplifiées rappellent les risques que ces produits chimiques font courir au personnel et précisent les premiers soins à appliquer. Les deux dernières annexes traitent de la définition des zones classées pour les forages à terre et les forages en mer. The personnel working in mud logging units at well sites must respect safety rules for the prevention of accidents and must know the instructions to be followed in case of danger. These recommendations concern the installation of logging units and the problems created by the highly diversified equipment in such units, including in particular numerous sensors scattered around the site and the network of cables linking the sensors to the unit. Eight appendixes review the risks inherent in the presence of hydrogen sulfide and the conditions for using protective equipment, the problems linked to any microwave ovens that may be installed, and the problems linked to the presence of radioactive sources. A large portion of these recommen-dations is devoted to

  2. Clinical and symptomatological study of pigs subjected to a lethal dose of integral gamma irradiation; Etude clinique et symptomatologique chez le porc soumis a une irradiation gamma totale a dose letale

    Energy Technology Data Exchange (ETDEWEB)

    Vaiman, M; Guenet, J -L; Maas, J; Nizza, P

    1966-05-01

    Results are reported from a clinical and haematological study on a Corsican species of pigs wholly exposed to an approximately lethal dose of {gamma} radiation. The aim of this work was to examine the changes in the irradiation syndrome of irradiation for pigs to make it thus possible to devise further experiments, in particular in the therapeutic field. The dose received was 285 rads (measured as the absorption in the vertical antero-posterior medial plane). Data are presented on cyto-haematological changes in the blood circulating immediately after irradiation, and followed up to death, and changes in the medullary cytology after irradiation. The clinical picture of lethal radiation injury in swine is described. (authors) [French] Les auteurs rapportent les resultats d'une etude clinique et hematologique chez des porcs de race corse irradies in toto a dose sensiblement letale. Le but de cette etude etait de connaitre l'evolution du syndrome aigu d'irradiation chez le porc et de permettre ainsi le developpement d'experimentations ulterieures, en particulier dans le domaine therapeutique. La dose delivree etait de 285 rad (en dose absorbee au niveau du plan median vertical anteroposterieur. L'etude a porte essentiellement: 1. Sur les modifications cyclo-hematologiques du sang circulant immediatement apres l'irradiation, pour les differentes lignees cellulaires; l'evolution de ces modifications a ete notee jusqu'a la mort; 2. Sur les modifications de la cytologie medullaire apres irradiation (evolution du myelogramme et essai d'evaluation de la cellularite de la moelle osseuse);: 3. Sur les signes cliniques, d'ailleurs tres discrets, observes chez les porcs apres irradiation. (auteurs)

  3. Contribution to the development of a gamma radiation camera for use in scintigraphy; Contribution a l'etude et a la realisation d'une camera a rayonnement gamma en vue d'une application a la scintigraphie

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-10-01

    This report constitutes an attempt to study systematically the properties of the detection head of a multichannel collimating grid camera. The object has been to show the disadvantages of present equipment, and to propose possible solutions for overcoming them: firstly by improving the methods used for collecting data, and the performances of the equipment doing the collecting; secondly by devising methods for processing the data so as to reduce image distortion and, first of all, the astigmatism due to the collimator. The first part deals with the study of the formation of the image by means of the collimating grid, the second with the examination of many systems which could be used for acquiring data. The last part summarizes the experiments carried out and proposes an experimental programme for the development of a prototype. (author) [French] Ce rapport constitue une tentative d'etude systematique des proprietes de la tete de detection d'une camera a grille collimatrice multicanal. Le but de cette etude est de souligner les inconvenients des dispositifs actuels et d'esquisser des solutions propres a y remedier: premierement, par l'amelioration du mode d'acquisition des donnees et des performances du sous-ensemble charge de cette acquisition; deuxiemement, par la recherche de methodes de traitement des donnees propres a reduire les distorsions de l'image et en premier lieu l'astigmatisme du au collimateur. La premiere partie en est devolue a l'etude de la formation de l'image par l'intermediaire de la grille collimatrice, la seconde a l'examen de nombreux systemes utilisables pour l'acquisition des donnees. La derniere partie resume les experiences effectuees et propose un programme de manipulations utiles a l'elaboration d'un prototype d'appareil. (auteur)

  4. Clinical and symptomatological study of pigs subjected to a lethal dose of integral gamma irradiation; Etude clinique et symptomatologique chez le porc soumis a une irradiation gamma totale a dose letale

    Energy Technology Data Exchange (ETDEWEB)

    Vaiman, M.; Guenet, J.-L.; Maas, J.; Nizza, P

    1966-05-01

    Results are reported from a clinical and haematological study on a Corsican species of pigs wholly exposed to an approximately lethal dose of {gamma} radiation. The aim of this work was to examine the changes in the irradiation syndrome of irradiation for pigs to make it thus possible to devise further experiments, in particular in the therapeutic field. The dose received was 285 rads (measured as the absorption in the vertical antero-posterior medial plane). Data are presented on cyto-haematological changes in the blood circulating immediately after irradiation, and followed up to death, and changes in the medullary cytology after irradiation. The clinical picture of lethal radiation injury in swine is described. (authors) [French] Les auteurs rapportent les resultats d'une etude clinique et hematologique chez des porcs de race corse irradies in toto a dose sensiblement letale. Le but de cette etude etait de connaitre l'evolution du syndrome aigu d'irradiation chez le porc et de permettre ainsi le developpement d'experimentations ulterieures, en particulier dans le domaine therapeutique. La dose delivree etait de 285 rad (en dose absorbee au niveau du plan median vertical anteroposterieur. L'etude a porte essentiellement: 1. Sur les modifications cyclo-hematologiques du sang circulant immediatement apres l'irradiation, pour les differentes lignees cellulaires; l'evolution de ces modifications a ete notee jusqu'a la mort; 2. Sur les modifications de la cytologie medullaire apres irradiation (evolution du myelogramme et essai d'evaluation de la cellularite de la moelle osseuse);: 3. Sur les signes cliniques, d'ailleurs tres discrets, observes chez les porcs apres irradiation. (auteurs)

  5. Contribution to the theoretical and experimental study of the electron-volt effect in N-P junctions; Contribution a l'etude theorique et experimentale de l'effet electronvoltaique dans les jonctions N-P

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Van, Dong [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-15

    -voltaique. On a montre ici que l'etude de la degradation du courant de court-circuit de la jonction peut permettre de determiner le niveau de recombinaison et les probabilites de capture des electrons et des trous, au meme titre que l'etude du declin de la duree de vie des porteurs minoritaires dans un cristal de type connu. Des experiences de bombardement des jonctions de Ge par des electrons de 2 MeV ont ete realisees avec un Van de Graaf. Des anomalies tres nettes de l'effet electron-voltaique a 100 deg. K ont ete constatees. On a essaye d'interpreter ces anomalies de la jonction en tenant compte d'autres phenomenes intervenant a basse temperature. Dans la quatrieme partie, on decrit les resultats de guerison des defauts et les moyens de protection contre les rayons {beta} trop energiques. On a observe une difference de guerison entre la duree de vie et la conductivite. Enfin, des experiences utilisant une couche de sulfure de cadmium pour transformer les particules {beta} du {sup 90}Sr-{sup 90}Y en photons ont donne des resultats interessants. (auteur)

  6. Contribution to the theoretical and experimental study of the electron-volt effect in N-P junctions; Contribution a l'etude theorique et experimentale de l'effet electronvoltaique dans les jonctions N-P

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Van, Dong [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-15

    semi-conducteur par les rayons {beta} de grande energie, selon la methode de l'effet electron-voltaique. On a montre ici que l'etude de la degradation du courant de court-circuit de la jonction peut permettre de determiner le niveau de recombinaison et les probabilites de capture des electrons et des trous, au meme titre que l'etude du declin de la duree de vie des porteurs minoritaires dans un cristal de type connu. Des experiences de bombardement des jonctions de Ge par des electrons de 2 MeV ont ete realisees avec un Van de Graaf. Des anomalies tres nettes de l'effet electron-voltaique a 100 deg. K ont ete constatees. On a essaye d'interpreter ces anomalies de la jonction en tenant compte d'autres phenomenes intervenant a basse temperature. Dans la quatrieme partie, on decrit les resultats de guerison des defauts et les moyens de protection contre les rayons {beta} trop energiques. On a observe une difference de guerison entre la duree de vie et la conductivite. Enfin, des experiences utilisant une couche de sulfure de cadmium pour transformer les particules {beta} du {sup 90}Sr-{sup 90}Y en photons ont donne des resultats interessants. (auteur)

  7. Site-specific growth of Au-Pd alloy horns on Au nanorods: A platform for highly sensitive monitoring of catalytic reactions by surface enhancement raman spectroscopy

    KAUST Repository

    Huang, Jianfeng

    2013-06-12

    Surface-enhanced Raman scattering (SERS) is a highly sensitive probe for molecular detection. The aim of this study was to develop an efficient platform for investigating the kinetics of catalytic reactions with SERS. To achieve this, we synthesized a novel Au-Pd bimetallic nanostructure (HIF-AuNR@AuPd) through site-specific epitaxial growth of Au-Pd alloy horns as catalytic sites at the ends of Au nanorods. Using high-resolution electron microscopy and tomography, we successfully reconstructed the complex three-dimensional morphology of HIF-AuNR@AuPd and identified that the horns are bound with high-index {11l} (0.25 < l < 0.43) facets. With an electron beam probe, we visualized the distribution of surface plasmon over the HIF-AuNR@AuPd nanorods, finding that strong longitudinal surface plasmon resonance concentrated at the rod ends. This unique crystal morphology led to the coupling of high catalytic activity with a strong SERS effect at the rod ends, making HIF-AuNR@AuPd an excellent bifunctional platform for in situ monitoring of surface catalytic reactions. Using the hydrogenation of 4-nitrothiophenol as a model reaction, we demonstrated that its first-order reaction kinetics could be accurately determined from this platform. Moreover, we clearly identified the superior catalytic activity of the rod ends relative to that of the rod bodies, owing to the different SERS activities at the two positions. In comparison with other reported Au-Pd bimetallic nanostructures, HIF-AuNR@AuPd offered both higher catalytic activity and greater detection sensitivity. © 2013 American Chemical Society.

  8. Multifragmentation in Au + Au collisions studied with AMD-V

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Akira [Tohoku Univ., Sendai (Japan). Faculty of Science

    1998-07-01

    AMD-V is an optimum model for calculation of multifragmentation in Au + Au collisions. AMD-V consider anti-symmetry of incident nucleus, target nucleus and fragments, furthermore, it treat the quantum effect to exist many channels in the intermediate and final state. 150 and 250 MeV/nucleon incident energy were used in the experiments. The data of multifragment atom in {sup 197}Au + {sup 197}Au collisions was reproduced by AMD-V calculation using Gognny force, corresponding to the imcompressibility of nuclear substance K = 228 MeV and its mean field depend on momentum. When other interaction (SKG 2 force, corresponding to K = 373 KeV) was used an mean field does not depend on momentum, the calculation results could not reproduce the experimental values, because nucleus and deuteron were estimated too large and {alpha}-particle and intermediate fragments estimated too small. (S.Y.)

  9. Le changement comme tradition dans la recherche et la formation a la recherche en biotechnologie et en peripherie Etude de cas en sciences de la sante, sciences naturelles et genie

    Science.gov (United States)

    Bourque, Claude Julie

    Le champ de la recherche scientifique et de la formation a la recherche est traverse depuis quelques dizaines d'annees par plusieurs courants et discours associes au changement, mais peu de travaux empiriques permettent de comprendre ce qui change concretement. C'est la contribution originale de cette these au champ de l'education, plus specifiquement a l'etude sociologique de l'enseignement superieur ou sont concentrees les activites liees a la triade thematique du programme doctoral dans lequel elle a ete produite : recherche, formation et pratique. L'enquete-terrain a ete realisee en 2009 et 2010 aupres de 808 repondants affilies a 60 etablissements au Quebec et a produit un vaste materiau de nature mixte (donnees quantitatives et qualitatives). Un portrait de la nebuleuse biotechnologique qui touche les secteurs des sciences de la sante, des sciences naturelles et du genie a ete realise. Ce domaine concerne des dizaines de disciplines et se revele de nature transdisciplinaire, mais les pratiques n'y sont pas davantage marquees par le changement que celles d'autres domaines connexes. Les dynamiques sociales ont fait l'objet d'analyses comparatives dans quatre contextes: le choix des programmes, des objets et des methodes, le financement, la diffusion et la planification de la carriere. Les resultats indiquent que les echanges entre les agents traditionnellement situes au coeur des activites de recherche dominent ces dynamiques dans tous les contextes etudies. L'etude des representations au fondement des pratiques a revele l'existence de trois ecoles de pensee qui coexistent dans le champ scientifique: academique, pragmatique et economiste. Ces ecoles permettent de categoriser les agents en fonction des zones de fractures qui marquent leurs oppositions tout en identifiant ce qu'ils ont en commun. Les representations et les pratiques liees a la formation temoignent d'un habitus plutot homogene, alors que les contradictions semblent plus souvent ancrees dans des

  10. Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting.

    Science.gov (United States)

    Benkouider, A; Ronda, A; David, T; Favre, L; Abbarchi, M; Naffouti, M; Osmond, J; Delobbe, A; Sudraud, P; Berbezier, I

    2015-12-18

    Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires. In this study, Au0.8Si0.2 nanocatalysts are synthesized via dewetting of Au layers on Si(111) during thermal annealing in an ultra-high vacuum. In the first part of the paper, the mechanism of homogeneous dewetting is analyzed as a function of the Au-deposited thickness (h Au). We distinguish three different dewetting regimes: (I) for a low thickness ([Formula: see text]), a submonolyer coverage of Au is stabilized and there is no dewetting. (II) For an intermediate thickness ([Formula: see text]), there is both dewetting and Au0.8Si0.2 phase formation. The size and density of the Au0.8Si0.2 clusters are directly related to h Au. When cooling down to room temperature, the clusters decompose and reject the Si at the Au/Si substrate interface. (III) For a large thickness ([Formula: see text]), only dewetting takes place, without forming AuSi clusters. In this regime, the dewetting is kinetically controlled by the self-diffusion of Au (activation energy ∼0.43 eV) without evidence of an Si-alloying effect. As a practical consequence, when relying solely on the homogeneous dewetting of Au/Si(111) to form the Au0.8Si0.2 catalysts (without a supply of Si atoms from vapor), regime II should be used to obtain good size and density control. In the second part of the paper, a process for ordering the catalysts using focused ion beam-(FIB) assisted dewetting (heterogeneous dewetting) is developed. We show that no matter what the FIB milling conditions and the Au nominal thickness are, dewetting is promoted by ion beam irradiation and is accompanied by the formation of Au0.8Si0.2 droplets. The droplets preferentially form on the patterned areas, while in similar annealing conditions, they do not form on the unpatterned areas. This behavior is attributed to the larger Au

  11. Transverse expansion in 197 Au + 197 Au collisions at RHIC

    International Nuclear Information System (INIS)

    Cheng, Y.; Liu, F.; Liu, K.; Schweda, K.; Xu, N.

    2003-01-01

    Using the RQMD model, transverse momentum distributions and particle ratios are studied for 197 Au + 197 Au collisions at √s NN = 200 GeV. In particular, they present results on the mean transverse momentum of charged pions, charged kaons, protons and anti-protons and compare with experimental measurements. They discuss an approach to study early partonic collectivity in high energy nuclear collisions

  12. Etude hyperfrequence et ultrasonore des supraconducteurs organiques kappa-(ET)(2)X (X = copper(thiocyanogen), copper[N(CN)(2)]bromine)

    Science.gov (United States)

    Frikach, Kamal

    2001-09-01

    Dans ce travail je presente une etude de l'impedance de surface, ainsi que de l'attenuation et la variation de la vitesse ultrasonores dans les etats normal et supraconducteur sur les composes organiques k-(ET)2X (X = Cu(SCN) 2, Cu[N(CN)2]Br). A partir des mesures d'impedance de surface, les deux composantes sigma 1 et sigma2 de la conductivite complexe sont extraites en utilisant le modele de Drude. Ces mesures montrent que la symetrie du parametre d'ordre dans ces composes est differente de celle du cas BCS. Afin de comprendre le profil de sigma1 (T) nous avons etudie les fluctuations supraconductrices a partir de la paraconductivite sigma'( T). Cette etude est rendue possible grace a la structure quasi-2D des composes k-(ET)2X dans lesquelles les fluctuations supraconductrices sont fortes. Ces dernieres sont observees sur deux decades de temperatures dans le Cu(SCN)2. L'application du modele de Aslamazov-Larkin 2D et 3D montre la possibilite du passage du regime 2D a haute temperature au regime 3D au voisinage de Tc. En se basant sur ce resultat, nous avons calcule la paraconductivite en utilisant une approche a l'ordre d'une boucle a partir du modele de Lawrence-Doniach. En tenant compte de la correction par la self energie dans la limite dynamique (17 GHz), l'ajustement de la paraconductivite calculee est en bon accord avec les donnees experimentales. Le couplage interplan obtenu est compatible avec le caractere quasi-2D des composes organiques. Le temps de relaxation des quasi-particules dans l'etat supraconducteur est ensuite extrait pour la premiere fois dans ces composes dont le comportement en fonction de la temperature est compatible avec la presence des noeuds dans le gap. Dans l'etat normal, la variation de la vitesse ultrasonore presente un comportement anormal caracterise par un fort ramollissement a T = 38 K et 50 K dans k-(ET) 2Cu(SCN)2 et k-(ET)2Cu[N(CN) 2]Br respectivement dont l'amplitude est independante du champ magnetique jusqu'a H = Hc 2

  13. Contribution to the micrographic study of uranium and its alloys; Contribution a l'etude micrographique de l'uranium et de ses alliages

    Energy Technology Data Exchange (ETDEWEB)

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

    1956-06-15

    The present report is the result of research carried out by the radio metallurgy section, to perfect micrographic techniques applicable to the study of samples of irradiated uranium. In the first part of this work, two polishing baths are developed, having the qualities with a minimum of disadvantages inherent in their respective compositions: they are, on the one hand perchloric acid-ethanol mixtures, and on the other hand a phospho-chromic-ethanol bath. In the chapter following, the micrographic attack of uranium is studied. The only satisfactory process is oxidation by cathode bombardment forming epitaxic layers. In the third chapter, an attempt is made to characterise the different surface states of the uranium by dissolution potential measurements and electronic diffraction. In the fourth chapter are given some examples of the application of these techniques to the micrographic study of various uranium alloys. In an appendix, it is shown how the chemical oxidation after phospho-chromic-alcohol polishing allows the different inclusions present in the molten uranium to be distinguished. By X-ray diffraction, uranium monocarbide and mononitride inclusions in particular are characterised. (author) [French] Le present rapport est le resultat de recherches effectuees au service de radiometallurgie pour la mise au point de techniques micrographiques applicables a l'etude d'echantillons d'uranium irradie. Dans la premiere partie de ce travail, nous mettons au point deux bains de polissage qui presentent les qualites inherentes a leur composition respective, avec le minimum d'inconvenients: ce sont d'une part des melanges acide perchlorique-ethanol, et d'autre part un bain phospho-chromique-ethanol. Dans le chapitre suivant, nous etudions l'attaque micrographique de l'uranium. Seul le procede d'oxydation par bombardement cathodique formant des couches epitaxiques, est satisfaisant. Dans le troisieme chapitre, nous essayons de caracteriser les differents etats de

  14. Some ways for the investigation of the solar modulation of cosmic electrons; Moyens d'etude de la modulation solaire des electrons cosmiques

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    In this report, we are investigating the solar modulation of cosmic electrons, in different ways. By comparing the calculated intensity with the measured intensity of positrons, we can evaluate the solar modulation of positrons, hence the modulation of negatons, since the modulation of negatons is probably the same that for positrons. By comparing the electron spectrum in interstellar space needed to explain the galactic background radio emission with that observed near the earth, we can deduce information about the modulation of electrons. We can investigate the modulation through the observation of its variations during the solar cycle. This different ways lead us to compatible results. In spite of the fact that the precision of the experimental data is poor, the modulation can be represented by: a constant or a form in exp(- K/Ro{beta}) under the rigidity Ro {approx_equal} 0,5 BV; a form in exp(- K/R) or exp(- K/R{beta}) above this rigidity. In addition, the investigation of both electrons and protons displays that the diffusion-convection theory is inadequate to explain all the features of the solar modulation. (author) [French] Dans le present rapport, nous etudions la modulation solaire des electrons cosmiques a l'aide de plusieurs methodes. Par comparaison entre l'intensite calculee et l'intensite mesuree des positons, on peut evaluer la modulation solaire des positons, et aussi des negatons, puisque la modulation des negatons est probablement la meme que celle des positons. Par le calcul, a partir du bruit de fond radio, du flux des electrons a l'exterieur du systeme solaire et sa confrontation avec le flux observe a l'orbite de la Terre permet l'etude de la modulation solaire des electrons. On peut aussi analyser ce phenomene de modulation pour l'etude de ses variations au cours du cycle solaire. Ces diverses methodes donnent des resultats compatibles. En depit de la precision mediocre des donnees experimentales, on peut caracteriser la modulation par: une

  15. Contribution to the micrographic study of uranium and its alloys; Contribution a l'etude micrographique de l'uranium et de ses alliages

    Energy Technology Data Exchange (ETDEWEB)

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

    1956-06-15

    The present report is the result of research carried out by the radio metallurgy section, to perfect micrographic techniques applicable to the study of samples of irradiated uranium. In the first part of this work, two polishing baths are developed, having the qualities with a minimum of disadvantages inherent in their respective compositions: they are, on the one hand perchloric acid-ethanol mixtures, and on the other hand a phospho-chromic-ethanol bath. In the chapter following, the micrographic attack of uranium is studied. The only satisfactory process is oxidation by cathode bombardment forming epitaxic layers. In the third chapter, an attempt is made to characterise the different surface states of the uranium by dissolution potential measurements and electronic diffraction. In the fourth chapter are given some examples of the application of these techniques to the micrographic study of various uranium alloys. In an appendix, it is shown how the chemical oxidation after phospho-chromic-alcohol polishing allows the different inclusions present in the molten uranium to be distinguished. By X-ray diffraction, uranium monocarbide and mononitride inclusions in particular are characterised. (author) [French] Le present rapport est le resultat de recherches effectuees au service de radiometallurgie pour la mise au point de techniques micrographiques applicables a l'etude d'echantillons d'uranium irradie. Dans la premiere partie de ce travail, nous mettons au point deux bains de polissage qui presentent les qualites inherentes a leur composition respective, avec le minimum d'inconvenients: ce sont d'une part des melanges acide perchlorique-ethanol, et d'autre part un bain phospho-chromique-ethanol. Dans le chapitre suivant, nous etudions l'attaque micrographique de l'uranium. Seul le procede d'oxydation par bombardement cathodique formant des couches epitaxiques, est satisfaisant. Dans le troisieme chapitre, nous essayons

  16. 29 August 2013 - J.-F. Jauslin, Directeur de l’Office fédéral de la culture (OFC) Ambassadeur suisse auprès de l’UNESCO et de l’OIF au 1er septembre 2013 Confédération suisse visite le centre visiteurs de l’expérience ATLAS ainsi que la caverne expérimentale d'ATLAS avec P. Jenny, ancien Porte-parole d'ATLAS. M. Bona, Conseiller du Directeur général pour les relations avec les Organisations internationales présent tout au long.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    29 August 2013 - J.-F. Jauslin, Directeur de l’Office fédéral de la culture (OFC) Ambassadeur suisse auprès de l’UNESCO et de l’OIF au 1er septembre 2013 Confédération suisse visite le centre visiteurs de l’expérience ATLAS ainsi que la caverne expérimentale d'ATLAS avec P. Jenny, ancien Porte-parole d'ATLAS. M. Bona, Conseiller du Directeur général pour les relations avec les Organisations internationales présent tout au long.

  17. The study of some thiazinic and indaminic dye syntheses induced by ionising radiation; Etude de quelques syntheses de colorants thianziniques et indaminiques amorcees par les rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-03-15

    With a view to finding some radiochemical reactions applicable on an industrial scale for evaluating the radioactive waste from nuclear reactors, a systematic study was made of the radiochemical synthesis of thiazinic dyes such as methylene blue and Lauths' violet, on which the first tests were carried out in 1954. The first part of the study concerned the identification and the dosage, during radiolysis, of dyes by means of their absorption spectra after separation from the reaction medium by adsorption chromatography or ion-exchange; other radiolysis products such as ammonium chloride and hydrogen peroxide were also identified. During a later stage by systematically varying the physico-chemical parameters it was possible to determine the most favourable conditions for radio-synthesis; the maximum radiochemical yields obtained had the following values: G (Lauths' violet) 1,65; G (Methylene blue) = 1,75. Furthermore, the study of the influence of variously substituted aminated products on the radiochemical yield showed the possibility of synthesising Bindsehedlers green and Wursters blue by radiochemical methods. Finally the discovery of a fundamental intermediate product, Wursters red, together with the kinetic study of the chemical synthesis of methylene blue made it possible to determine the main stages of the reaction mechanism and to decide which of these stages could be attributed to ionising radiations in the case of the radiochemical synthesis. (author) [French] Dans le but de trouver des reactions radiochimiques susceptibles d'une application industrielle pour valoriser les dechets radioactifs provenant des reacteurs nucleaires, il a ete entrepris une etude systematique de la synthese radiochimique des colorants thiazimiques tels que le Bleu de Methylene et le Violet de Lauth dont les premiers essais ont ete effectues par Loiseleur en 1954. La premiere partie de l'etude a porte sur l'identification et le dosage des colorants formes au cours de la radiolyse

  18. Applications of prospecting geochemical techniques to the search for and to the study of uranium deposits in metropolitan France; Applications des techniques geochimiques de prospection a la recherche et a l'etude des gites uraniferes en France metropolitaine

    Energy Technology Data Exchange (ETDEWEB)

    Grimbert, Arnold

    1957-07-01

    After having recalled facts which leaded the CEA to use new geochemical techniques for the prospecting of uranium deposits through sampling and analysis of soils and waters, the author describes the organisation and methods implemented for this prospecting activity: team composition for sampling and analysis, role of each engineer and technician in the prospecting stages (preliminary study, routine prospecting, result interpretation), sampling and analysis processes. He also reports campaigns of geochemical prospecting: study of the La Chapelle Largeau deposit (objectives, geological context, preliminary study, routine prospecting, study of geochemical anomalies), tactical research on Verneix indices (study of radioactivity anomaly discovered by radio-prospecting), strategical searches in a non prospected area in the South of Avallon. The author discusses the issues of efficiency and cost price of this geochemical prospecting technique in soils and in waters. Appendices present the equipment and operation modality for soil sampling, and for soil sample preparation, and principles, equipment and products for soil analysis and for water analysis [French] A la suite des resultats satisfaisants obtenus dans la recherche de methodes de dosage adaptees au cas de l'uranium, la Direction des Recherches Minieres du Commissariat a l'Energie atomique a decide, en decembre 1954, d'utiliser, conjointement avec les methodes classiques de prospection, les techniques geochimiques pour la recherche et l'etude des gites uraniferes. Ces applications pratiques ont ete confiees a une Section de Geochimie dont l'organisation, les moyens en personnel et en materiel, ainsi que les methodes de travail, font l'objet d'un expose detaille. Quelques exemples de prospection, en France metropolitaine, montrent la nature des problemes poses (etude d'un gisement connu, recherche tactique sur des indices, recherche strategique dans une region non prospectee), les methodes utilisees pour les

  19. Face au risque

    CERN Document Server

    Grosse, Christian; November, Valérie

    2007-01-01

    Ce volume collectif sur le risque inaugure la collection L'ÉQUINOXE. Ancré dans l'histoire pour mesurer les continuités et les ruptures, il illustre la manière dont les sciences humaines évaluent et mesurent les enjeux collectifs du risque sur les plans politiques, scientifiques, énergétiques, juridiques et éthiques. Puisse-t-il nourrir la réflexion sur la culture et la prévention du risque. Ses formes épidémiques, écologiques, sociales, terroristes et militaires nourrissent les peurs actuelles, structurent les projets sécuritaires et constituent - sans doute - les défis majeurs à notre modernité. Dans la foulée de la richesse scientifique d'Equinoxe, L'ÉQUINOXE hérite de son esprit en prenant à son tour le pari de contribuer - non sans risque - à enrichir en Suisse romande et ailleurs le champ éditorial des sciences humaines dont notre société a besoin pour forger ses repères. Après Face au risque suivra cet automne Du sens des Lumières. (MICHEL PORRET Professeur Ordinaire à la F...

  20. Diastereoselective Au-Catalyzed Allene Cycloisomerizations to Highly Substituted Cyclopentenes.

    Science.gov (United States)

    Reeves, Ryan D; Phelps, Alicia M; Raimbach, William A T; Schomaker, Jennifer M

    2017-07-07

    Site- and regiocontrolled Au-catalyzed allene carbocyclizations furnish highly substituted cyclopentenes in >1:1 dr. Significant substitution on the substrate is tolerated, with potential to install five contiguous stereocenters after alkene functionalization. Major challenges include identifying a Au/Cu catalyst that controls both the relative rates of allene epimerization/cyclization and the facial selectivity in addition of a metal enolate to the allene. Experiments to achieve stereodivergent cyclizations and transform key cyclopentenes into useful synthetic building blocks are described.

  1. Plasmon enhanced water splitting mediated by hybrid bimetallic Au-Ag core-shell nanostructures.

    Science.gov (United States)

    Erwin, William R; Coppola, Andrew; Zarick, Holly F; Arora, Poorva; Miller, Kevin J; Bardhan, Rizia

    2014-11-07

    In this work, we employed wet chemically synthesized bimetallic Au-Ag core-shell nanostructures (Au-AgNSs) to enhance the photocurrent density of mesoporous TiO2 for water splitting and we compared the results with monometallic Au nanoparticles (AuNPs). While Au-AgNSs incorporated photoanodes give rise to 14× enhancement in incident photon to charge carrier efficiency, AuNPs embedded photoanodes result in 6× enhancement. By varying nanoparticle concentration in the photoanodes, we observed ∼245× less Au-AgNSs are required relative to AuNPs to generate similar photocurrent enhancement for solar fuel conversion. Power-dependent measurements of Au-AgNSs and AuNPs showed a first order dependence to incident light intensity, relative to half-order dependence for TiO2 only photoanodes. This indicated that plasmonic nanostructures enhance charge carriers formed on the surface of the TiO2 which effectively participate in photochemical reactions. Our experiments and simulations suggest the enhanced near-field, far-field, and multipolar resonances of Au-AgNSs facilitating broadband absorption of solar radiation collectively gives rise to their superior performance in water splitting.

  2. 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.

    recension des ecrits sur le changement de comportement en environnement. Nous explorons egalement la famille comme systeme fonctionnel de sorte a mieux comprendre ce contexte d'action environnementale qui est, a notre connaissance, peu etudie. Dans le deuxieme article, nous presentons nos resultats de recherche concernant les facteurs d'influence observes ainsi que les competences manifestees au cours du processus d'adoption de nouveaux comportements environnementaux dans trois familles. Enfin, le troisieme article presente les resultats du cas d'une quatrieme famille ou les membres vivent depuis longtemps des modes de vie ecologique. Dans le cadre d'une demarche d'analyse par theorisation ancree, l'etude de ce cas modele nous a permis d'approfondir les categories conceptuelles identifiees dans le deuxieme article de sorte a produire une modelisation de l'integration de comportements environnementaux dans le contexte de la famille. Les conclusions degagees grace a la recension des ecrits nous ont permis d'identifier les elements qui pourraient influencer l'adoption de comportements environnementaux dans des familles. La recension a aussi permis une meilleure comprehension des divers facteurs qui peuvent affecter l'adoption de comportements environnementaux et, enfin, elle a permis de mieux cerner le phenomene de changement de comportement dans le contexte de la famille consideree comme un systeme. En appliquant un processus d'analyse inductif, a partir de nos donnees qualitatives, les resultats de notre etude multi-cas nous ont indique que deux construits conceptuels semblent influencer l'adoption de comportements environnementaux en famille : 1) les valeurs biospheriques communes au sein de la famille et 2) les competences collectivement mises a profit collectivement durant l'essai de nouveaux comportements environnementaux. Notre modelisation du processus de changement dans des familles indique aussi qu'une dynamique familiale collaborative et la presence d'un groupe de

  3. Study of beam-plasma interactions in the presence of a magnetic field; Etude d'interactions faisceau-plasma en la presence d'un champ magnetique

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-12-15

    The instabilities developing in a 'beam-plasma' system and in a 'double-beam' system in the presence of a magnetic field are discussed theoretically starting from the conductivity tensor expression for a multi-beam system. Oblique propagation is taken into account and this leads to the introduction of certain instability mechanisms which would not appear in the case of a propagation which is purely parallel or perpendicular to the magnetic field. Two experiments are described: a) Study of the collision of two counterstreaming electron beams: An instability has been observed experimentally which leads to the generation of a stationary cyclotron wave having a frequency of {omega}{sub ce}/2. A description is given of the measurement of the interaction frequency, of the wavelength and of the build-up time of the wave. b) Study of a 'beam-plasma' system: A description is given of the measurement of the spectra of excited waves and of the perturbation of the beam velocity distribution at the plasma-exit. This perturbation is very pronounced when 'plasma-plasma' interaction appears in the system. A study into cyclotron oscillations produced in the plasma by excitation due to the passage of the beam is also described in this report. (author) [French] Les instabilites se developpant dans un systeme 'faisceau-plasma' et dans un systeme 'faisceau-faisceau' en la presence d'un champ magnetique sont discutees theoriquement a partir de l'expression du tenseur de conductivite d'un systeme multi-faisceaux. La propagation oblique est prise en consideration, ce qui introduit certains mecanismes d'instabilite qui n'apparaitraient pas pour une propagation purement parallele ou perpendiculaire au champ magnetique. Deux experiences sont decrites: a) Etude de la collision de deux faisceaux d'electrons: Une instabilite conduisant a la generation d'une onde cyclotronique stationnaire a la frequence {omega}{sub ce}/2 a ete observee experimentalement. Les mesures de la frequence d

  4. Prediction du profil de durete de l'acier AISI 4340 traite thermiquement au laser

    Science.gov (United States)

    Maamri, Ilyes

    Les traitements thermiques de surfaces sont des procedes qui visent a conferer au coeur et a la surface des pieces mecaniques des proprietes differentes. Ils permettent d'ameliorer la resistance a l'usure et a la fatigue en durcissant les zones critiques superficielles par des apports thermiques courts et localises. Parmi les procedes qui se distinguent par leur capacite en terme de puissance surfacique, le traitement thermique de surface au laser offre des cycles thermiques rapides, localises et precis tout en limitant les risques de deformations indesirables. Les proprietes mecaniques de la zone durcie obtenue par ce procede dependent des proprietes physicochimiques du materiau a traiter et de plusieurs parametres du procede. Pour etre en mesure d'exploiter adequatement les ressources qu'offre ce procede, il est necessaire de developper des strategies permettant de controler et regler les parametres de maniere a produire avec precision les caracteristiques desirees pour la surface durcie sans recourir au classique long et couteux processus essai-erreur. L'objectif du projet consiste donc a developper des modeles pour predire le profil de durete dans le cas de traitement thermique de pieces en acier AISI 4340. Pour comprendre le comportement du procede et evaluer les effets des differents parametres sur la qualite du traitement, une etude de sensibilite a ete menee en se basant sur une planification experimentale structuree combinee a des techniques d'analyse statistiques eprouvees. Les resultats de cette etude ont permis l'identification des variables les plus pertinentes a exploiter pour la modelisation. Suite a cette analyse et dans le but d'elaborer un premier modele, deux techniques de modelisation ont ete considerees, soient la regression multiple et les reseaux de neurones. Les deux techniques ont conduit a des modeles de qualite acceptable avec une precision d'environ 90%. Pour ameliorer les performances des modeles a base de reseaux de neurones, deux

  5. Theoretical study and construction of a multichannel {beta} spectrometer with uniform magnetic field; Etude et realisation d'un spectrometre {beta} multivoies a champ magnetique uniforme

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-09-01

    After a brief survey of the interest of a multichannel beta spectrometer for studying decay schemes of short lived nuclides (30 seconds minimum, the theoretically well known characteristics of uniform magnetic field analyser (image of a large source, transmission and resolution) are briefly remembered. In the second part, the apparatus built as a result of these calculations is described. This apparatus allows the determination of beta spectra by simultaneous determination of the beta spectra in coincidence with four gamma rays predetermined in the gamma spectrum of the studied nuclide. Finally, in the last part, the experimental characteristics of the spectrometer (calibration in energy and transmission) and the first measurement of beta spectra ({sup 155}Sm) and of coincidences ({sup 24}Na), are given. (author) [French] Apres avoir brievement souligne l'interet pratique que presente un spectrometre multivoies pour l'etude des schemas de desintegration des corps radioactifs de courtes periodes (30 secondes au maximum), l'auteur effectue un rappel des caracteristiques theoriques bien connues d'un analyseur magnetique a champ uniforme (image d'une source etendue) calcul de la transmission et du pouvoir de resolution. Une deuxieme partie est consacree a la description de l'appareil realise d'apres ces calculs. Cet appareil permet le releve des spectres beta par detection, simultanee de dix groupes d'electrons d'energies differentes; il permet egalement le releve simultane des spectres beta en coincidence avec quatre rayonnements gammas preselectionnes a l'avance dans le spectre gamma du corps etudie. Dans une derniere partie enfin, sont donnees les caracteristiques experimentales du spectrometre (etalonnage en energie et en transmission) ainsi que les premiers resultats des etudes de spectre beta ({sup 155}Sm) et de coincidence ({sup 24}Na). (auteur)

  6. Contribution to the study of recoil species produced by potassium ferrocyanide neutron irradiation; Contribution a l'etude de la reactivite des especes de recul dans le ferrocyanure de potassium irradie aux neutrons thermiques

    Energy Technology Data Exchange (ETDEWEB)

    Meriadec Vernier de Byans, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-04-01

    The chemical species produced by potassium ferrocyanide neutron irradiation were separated and identified. The study of their behaviour upon thermal annealing has allowed to establish a scheme of reaction as well as a kinetic treatment of the data. Activation energies are determined in different conditions and the effects of radiation dose, oxygen and water of crystallisation upon the activation energies were studied. Preliminary E.S.R. data and its relevance to the decomposition process is also discussed. (authors) [French] On a separe et identifie les differentes especes chimiques produites par irradiation neutronique de ferrocyanure de potassium. L'etude de leur comportement au cours du recuit thermique a permis l'application de differentes cinetiques et l'etablissement d'un schema de reaction. On a deterrmine la valeur des energies d'activation dans differentes conditions de recuit ainsi que l'influence de la dose de radiations, de l'oxygene et de l'eau de cristallisation sur ces energies. Une serie de mesures de resonance paramagnetique electronique a complete cette etude. (auteurs)

  7. A simple approach for facile synthesis of Ag, anisotropic Au and bimetallic (Ag/Au) nanoparticles using cruciferous vegetable extracts

    International Nuclear Information System (INIS)

    Jacob, Jasmine; Mukherjee, Tulsi; Kapoor, Sudhir

    2012-01-01

    We present a simple and straightforward approach for the synthesis and stabilization of relatively monodisperse Ag, Au and bimetallic (Ag/Au) nanoparticles by using cruciferous vegetable (green/red) extracts by simply adjusting the pH environment in the aqueous medium. The vegetable extracts act both as reducing and capping agents. The monometallic and bimetallic nanoparticles of Ag and Au so obtained were characterized by UV–visible spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). It is shown that red cabbage extract can be used for the preparation of anisotropic Au nanoparticles. The formation of Au anisotropic nanoparticles was found to depend on a number of environmental factors, such as the pH of the reaction medium, reaction time, and initial reactant concentrations. Additionally, it is shown that these extract-stabilized Au and Ag nanoparticles can be used as a seed for preparation of bimetallic Au/Ag nanoparticles. For bimetallic alloy nanoparticles the absorption peak was observed between the two maxima of the corresponding metallic particles. The surface plasmon absorption maxima for bimetallic nanoparticles changed linearly with increasing Au mole ratio content in various alloy compositions. It has been shown that the formation of hollow Au spheres depends on the experimental conditions. - Graphical abstract: TEM image of gold nanoparticles at pH 3.27 formed by red cabbage extract. Highlights: ► First report on the reactivity of the extracts toward metal ions using a spectrophotometric technique. ► Red cabbage extract has better reducing properties than green cabbage extract. ► Red cabbage extract can reduce metal ions at any pH. ► Reduction of metal ions can have important consequences in the study of soil chemistry.

  8. A simple approach for facile synthesis of Ag, anisotropic Au and bimetallic (Ag/Au) nanoparticles using cruciferous vegetable extracts

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Jasmine; Mukherjee, Tulsi; Kapoor, Sudhir, E-mail: sudhirk@barc.gov.in

    2012-10-01

    We present a simple and straightforward approach for the synthesis and stabilization of relatively monodisperse Ag, Au and bimetallic (Ag/Au) nanoparticles by using cruciferous vegetable (green/red) extracts by simply adjusting the pH environment in the aqueous medium. The vegetable extracts act both as reducing and capping agents. The monometallic and bimetallic nanoparticles of Ag and Au so obtained were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). It is shown that red cabbage extract can be used for the preparation of anisotropic Au nanoparticles. The formation of Au anisotropic nanoparticles was found to depend on a number of environmental factors, such as the pH of the reaction medium, reaction time, and initial reactant concentrations. Additionally, it is shown that these extract-stabilized Au and Ag nanoparticles can be used as a seed for preparation of bimetallic Au/Ag nanoparticles. For bimetallic alloy nanoparticles the absorption peak was observed between the two maxima of the corresponding metallic particles. The surface plasmon absorption maxima for bimetallic nanoparticles changed linearly with increasing Au mole ratio content in various alloy compositions. It has been shown that the formation of hollow Au spheres depends on the experimental conditions. - Graphical abstract: TEM image of gold nanoparticles at pH 3.27 formed by red cabbage extract. Highlights: Black-Right-Pointing-Pointer First report on the reactivity of the extracts toward metal ions using a spectrophotometric technique. Black-Right-Pointing-Pointer Red cabbage extract has better reducing properties than green cabbage extract. Black-Right-Pointing-Pointer Red cabbage extract can reduce metal ions at any pH. Black-Right-Pointing-Pointer Reduction of metal ions can have important consequences in the study of soil chemistry.

  9. Proceedings of the European Symposium on Pressure Equipment - ESOPE 2007; Actes des Journees d'Etudes Europeennes Equipements sous Pression - ESOPE 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Every three years, and since thirty years, the AFIAP organizes a symposium where the experts and actors working in the field of pressure equipments, whether fixed or transportable, can meet and exchange on all developments related to their activity. What was at first called the 'National Congress on the technology of pressure components', and later the 'Study Days on pressure components', became since 2001 the 'European Symposium on Pressure Equipment' (ESOPE), so marking an opening to the European and International fields in a context marked by the application of the European Directives applicable to these equipments. The 2001 symposium was more particularly dedicated to the application of the directives harmonizing the construction of equipments, and the 2004 symposium was more particularly centred on the management of equipments in operation. For the ESOPE 2007 Symposium, the organizing committee wished to resume these two subjects under the aspects of the safety, the competitiveness, as well as the innovation. The plenary session of the last day will be completely dedicated to these subjects and will include a Panel discussion, where National and European authorities, representatives of manufacturers and users, as well as experts engaged in developments and new projects will express their views. These exchanges will also permit to answer the questions expressed by the participants. Every symposium has thus a main orientation, but shall also be the place of exchanges on the different subjects wished by the profession. The traditional technical sessions are consequently maintained: - Sessions on Design and Materials, - Sessions on Fabrication, - Sessions on Fitness for Service, and a special session dedicated to the National, European and International Codes is added, the afternoon of the first day. The plenary Opening session is also devoted to this last subject with lectures on the evolutions of European regulations, the

  10. Law n. 2006-1537 of the 7 December 2006 relative to the energy sector; Loi n. 2006-1537 du 7 decembre 2006 relative au secteur de l'energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-12-15

    This law concerns the market opening and the free choice of the consumers, the dispositions relative to the electricity and gas distribution and the dispositions relative to the Gaz De France capital and the government control. (A.L.B.)

  11. Cell for studying electron-adsorbed gas interactions; Cellule d'etudes des interactions electron-gaz adsorbe

    Energy Technology Data Exchange (ETDEWEB)

    Golowacz, H; Degras, D A [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires, Deptartement de Physique des Plasmas et de la Fusion Controlee, Service de Physique Appliquee, Service de Physique des Interractions Electroniques, Section d' Etude des Interactions Gaz-Solides

    1967-07-01

    The geometry and the technology of a cell used for investigations on electron-adsorbed gas interactions are described. The resonance frequencies of the surface ions which are created by the electron impact on the adsorbed gas are predicted by simplified calculations. The experimental data relative to carbon monoxide and neon are in good agreement with these predictions. (authors) [French] Les caracteristiques geometriques et technologiques generales d'une cellule d'etude des interactions entre un faisceau d'electrons et un gaz adsorbe sont donnees. Un calcul simplifie permet de prevoir les frequences de resonance des ions de surface crees par l'impact des electrons sur le gaz adsorbe. Les donnees experimentales sur l'oxyde de carbone et le neon confirment les previsions du calcul. (auteurs)

  12. Tuning SPT-3G Transition-Edge-Sensor Electrical Properties with a Four-Layer Ti-Au-Ti-Au Thin-Film Stack

    Science.gov (United States)

    Carter, F. W.; Ade, P. A. R.; Ahmed, Z.; Anderson, A. J.; Austermann, J. E.; Avva, J. S.; Thakur, R. Basu; Bender, A. N.; Benson, B. A.; Carlstrom, J. E.; Cecil, T.; Chang, C. L.; Cliche, J. F.; Cukierman, A.; Denison, E. V.; de Haan, T.; Ding, J.; Divan, R.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Foster, A.; Gannon, R. N.; Gilbert, A.; Groh, J. C.; Halverson, N. W.; Harke-Hosemann, A. H.; Harrington, N. L.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Huang, N.; Irwin, K. D.; Jeong, O. B.; Jonas, M.; Khaire, T.; Kofman, A. M.; Korman, M.; Kubik, D.; Kuhlmann, S.; Kuo, C. L.; Kutepova, V.; Lee, A. T.; Lowitz, A. E.; Meyer, S. S.; Michalik, D.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Noble, G. I.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Ruhl, J. E.; Saunders, L. J.; Sayre, J. T.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J. A.; Stan, L.; Stark, A. A.; Story, K. T.; Suzuki, A.; Tang, Q. Y.; Thompson, K. L.; Tucker, C.; Vale, L. R.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Yoon, K. W.; Young, M. R.

    2018-04-01

    We have developed superconducting Ti transition-edge sensors with Au protection layers on the top and bottom for the South Pole Telescope's third-generation receiver (a cosmic microwave background polarimeter, due to be upgraded this austral summer of 2017/2018). The base Au layer (deposited on a thin Ti glue layer) isolates the Ti from any substrate effects; the top Au layer protects the Ti from oxidation during processing and subsequent use of the sensors. We control the transition temperature and normal resistance of the sensors by varying the sensor width and the relative thicknesses of the Ti and Au layers. The transition temperature is roughly six times more sensitive to the thickness of the base Au layer than to that of the top Au layer. The normal resistance is inversely proportional to sensor width for any given film configuration. For widths greater than five micrometers, the critical temperature is independent of width.

  13. Study of the artificial radioactivity of the marine medium using gamma spectrometry (1962-1966); Etude de la radioactivite artificielle du milieu marin par spectrometrie gamma (1962-1966)

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    The results described in this study are relative to the artificial radioactivity of such elements as zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 and praseodymium-144 which were present in the atmospheric fallout between 1962 and 1964, and their incidence in superficial marine waters. Various physical, chemical or biological processes are studied by a high sensitivity gamma ray spectrometry technic, using those radioelements as 'tracers'. The change of state in sea water of an important fraction (about 50 per cent) of the radioactive particles going into the soluble phase - this phenomenon was not expected for those radioelements - controls the processes of accumulation in the planktonic biomass and the diffusion towards deeper waters. On the other hand, an 'in situ' spectrometry method is described. It enables the direct measurement in the sea of very low concentrations of some gamma ray emitters. The application of this method has made possible to carry out numerous observations in the surface waters of the Western Mediterranean sea and in the Bay of Biscay. It is shown that the mixing depth is closely connected to the depth of the thermocline. An accumulation process at this level is observed. The diffusion coefficients are similar to the thermal turbulent coefficient. The existence during several months of 'compartments' is established for the surface waters of the Bay of Biscay. From the establishment of the budget of fall-out, a comparative study shows that the rate of radioactive fallout on the maritime zone considered is always two to three times higher than on the neighbouring continental regions. Several explanations of this phenomenon are discussed. (author) [French] Les resultats decrits dans cette etude concernent la radioactivite artificielle sous forme de zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 et praseodyme-144 apportee par la retombee atmospherique entre 1962 et 1964 et les

  14. Study of the artificial radioactivity of the marine medium using gamma spectrometry (1962-1966); Etude de la radioactivite artificielle du milieu marin par spectrometrie gamma (1962-1966)

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    The results described in this study are relative to the artificial radioactivity of such elements as zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 and praseodymium-144 which were present in the atmospheric fallout between 1962 and 1964, and their incidence in superficial marine waters. Various physical, chemical or biological processes are studied by a high sensitivity gamma ray spectrometry technic, using those radioelements as 'tracers'. The change of state in sea water of an important fraction (about 50 per cent) of the radioactive particles going into the soluble phase - this phenomenon was not expected for those radioelements - controls the processes of accumulation in the planktonic biomass and the diffusion towards deeper waters. On the other hand, an 'in situ' spectrometry method is described. It enables the direct measurement in the sea of very low concentrations of some gamma ray emitters. The application of this method has made possible to carry out numerous observations in the surface waters of the Western Mediterranean sea and in the Bay of Biscay. It is shown that the mixing depth is closely connected to the depth of the thermocline. An accumulation process at this level is observed. The diffusion coefficients are similar to the thermal turbulent coefficient. The existence during several months of 'compartments' is established for the surface waters of the Bay of Biscay. From the establishment of the budget of fall-out, a comparative study shows that the rate of radioactive fallout on the maritime zone considered is always two to three times higher than on the neighbouring continental regions. Several explanations of this phenomenon are discussed. (author) [French] Les resultats decrits dans cette etude concernent la radioactivite artificielle sous forme de zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 et praseodyme-144 apportee par la retombee

  15. 197Au Moessbauer study of nano-sized gold catalysts supported on Mg(OH)2 and TiO2

    International Nuclear Information System (INIS)

    Kobayashi, Y.; Nasu, S.; Tsubota, S.; Haruta, M.

    2000-01-01

    We have studied nano-sized Au catalysts supported on Mg(OH) 2 and TiO 2 using 197 Au Moessbauer spectroscopy. 197 Au Moessbauer spectra observed for Au/Mg(OH) 2 catalysts can be decomposed into one singlet with zero isomer shift and several doublets. One of the doublets shows an isomer shift that is typical for Au I , and other doublets are due to Au III . The relative area of the Au I component shows the maximum value for a specimen calcined at 523 K, which also shows the highest catalytic activity

  16. High p$\\perp$ inclusive charged hadron distributions in Au+Au collisions at √sNN = 130 GeV at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Bum Jin [Univ. of Texas, Austin, TX (United States)

    2003-08-01

    This thesis reports the measurement of the inclusive charged particle (h+ + h-) p$\\perp$ spectra for 1.7 < p$\\perp$ < 6 GeV/c at midrapidity (|η| < 0.5) as a function of various centrality classes in Au+Au collisions at √sNN = 130 GeV. Hadron suppression is observed relative to both scaled NN and peripheral Au+Au reference data, possibly indicating non-Abelian radiative energy loss in a hot, dense medium.

  17. Magnetic holes in the solar wind between 0.3 AU and 17 AU

    Directory of Open Access Journals (Sweden)

    K. Sperveslage

    2000-01-01

    Full Text Available Magnetic holes (MHs are depressions of the magnetic field magnitude. Turner et al. (1977 identified the first MHs in the solar wind and determined an occurrence rate of 1.5 MHs/d. Winterhalter et al. (1994 developed an automatic identification criterion to search for MHs in Ulysses data in the solar wind between 1 AU and 5.4 AU. We adopt their criterion to expand the search to the heliocentric distances down to 0.3 AU using data from Helios 1 and 2 and up to 17 AU using data from Voyager 2. We relate our observations to two theoretical approaches which describe the so-called linear MHs in which the magnetic vector varies in magnitude rather than direction. Therefore we focus on such linear MHs with a directional change less than 10º. With our observations of about 850 MHs we present the following results: Approximately 30% of all the identified MHs are linear. The maximum angle between the initial magnetic field vector and any vector inside the MH is 20º in average and shows a weak relation to the depth of the MHs. The angle between the initial magnetic field and the minimum variance direction of those structures is large and very probably close to 90º. The MHs are placed in a high β environment even though the average solar wind shows a smaller β. The widths decrease from about 50 proton inertial length in a region between 0.3 AU and 0.4 AU heliocentric distance to about 15 proton inertial length at distances larger than 10 AU. This quantity is correlated with the β of the MH environments with respect to the heliocentric distance. There is a clear preference for the occurrence of depressions instead of compressions. We discuss these results with regard to the main theories of MHs, the mirror instability and the alternative soliton approach. Although our observational results are more consistent with the soliton theory we favour a combination of both. MHs might be the remnants of initial mirror mode structures which can be described as

  18. L'État de l'environnement au Canada

    National Research Council Canada - National Science Library

    1991-01-01

    ...) exploitant ces composantes ou influant sur elles. La troisieme partie presente six etudes de cas regionaux qui, collectivement, refletent jusqu'a un certain point la gamme des problemes environnementaux du pays...

  19. Cobalt-60 and Caesium-137 Gamma Sources; Sources de rayonnement gamma au cobalt-60 et au cesium-137; Gamma-istochniki iz kobal'ta-605 i tseziya-137; Fuentes gamma de cobalto-60 y de cesio-137

    Energy Technology Data Exchange (ETDEWEB)

    Kulish, E E; Fradkin, G M [Academy of Sciences of the USSR, Moscow, Union of Soviet Socialits Republics (Russian Federation)

    1960-07-15

    The paper gives the main technical characteristics of gamma sources produced in the USSR using cobalt-60 and caesium-137 and discusses some of the problems of their production technology. The paper contains information on the radiation spectra of Co{sup 60} and Cs{sup 137} and of the source material from which they are prepared. Data are given on the dependence of the activity of cobalt sources upon the intensity of the neutron beam and the geometrical size of the sample. The yield of caesium by uranium fission is also analyzed. The problem of hermetic sealing of the sources is discussed and a complete nomenclature of all the sources manufactured in the USSR are listed, their size and activity also being indicated. In conclusion a comparison of Co{sup 60} and Cs{sup 137} sources is made. (author) [French] Cette communication expose les caracteristiques techniques fondamentales des sources de rayonnement gamma a base de cobalt-60 et de cesium-137 pro- duites en URSS; on y examine egalement certaines questions relatives a la technologie de leur production. La communication contient des donnees sur la nature du rayonnement des isotopes {sup 60}Co et {sup 137}Cs, ainsi que sur celle des matieres brutes utilisees pour leur preparation. On donne les resultats obtenus lors de l'etude de la variation de l'activite des sources au cobalt en fonction de la valeur du flux de neutrons et des dimensions geometriques de l'echantillon, ainsi que les resultats relatifs a la valeur du rendement en isotopes de cesium lors de la fission des noyaux d'uranium. On etudie ensuite les procedes pour assurer l'hermeticite de ces sources. Suit une nomenclature complete des sources produites en URSS, comportant des indications sur leurs dimensions geometriques et sur les valeurs de leur activite. Enfin, il est procede a une comparaison des sources au {sup 60}Co et au {sup 137}Cs. (author) [Spanish] En este informe se describen las principales caracteristicas tecnicas de las fuentes gamma de

  20. The oscillatory behavior of heated channels: an analysis of the density effect. Part I. The mechanism (non linear analysis). Part II. The oscillations thresholds (linearized analysis); Sur le comportement oscillatoire de canaux chauffes. - Etude theorique de l'effet de densite. 1ere partie: le mecanisme (analyse non lineaire), 2eme partie: seuils d'oscillation (analyse lineaire)

    Energy Technology Data Exchange (ETDEWEB)

    Boure, J [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, 38 (France)

    1967-07-01

    The problem of the oscillatory behavior of heated channels is presented in terms of delay-times and a density effect model is proposed to explain the behavior. The density effect is the consequence of the physical relationship between enthalpy and density of the fluid. In the first part non-linear equations are derived from the model in a dimensionless form. A description of the mechanism of oscillations is given, based on the analysis of the equations. An inventory of the governing parameters is established. At this point of the study, some facts in agreement with the experiments can be pointed out. In the second part the start of the oscillatory behavior of heated channels is studied in terms of the density effect. The threshold equations are derived, after linearization of the equations obtained in Part I. They can be solved rigorously by numerical methods to yield: -1) a relation between the describing parameters at the onset of oscillations, and -2) the frequency of the oscillations. By comparing the results predicted by the model to the experimental behavior of actual systems, the density effect is very often shown to be the actual cause of oscillatory behaviors. (author) [French] Premiere partie: mecanisme (equations non linearisees). On expose le probleme du comportement oscillatoire des canaux chauffes en mettant l'accent sur la presence de retards dans le systeme et on propose un modele a 'effet de densite' pour expliquer ce comportement. L'effet de densite est la consequence de la relation physique entre l'enthalpie et la masse volumique du fluide. Les equations non lineaires du schema mathematique correspondant sont etablies et mises sous forme adimensionnelle. L'analyse de ces equations conduit a une description du mecanisme des oscillations. On donne la liste des parametres dont depend le comportement du modele. A ce stade de l'etude, on peut deja relever dans ce comportement plusieurs faits conformes a l'experience. Deuxieme partie: seuils d

  1. L’apprentissage au cern

    CERN Multimedia

    2007-01-01

    pour les professions d’électronicien(ne) et de laborantin(e) en physique L’apprentissage au CERN est régi par les lois, règlements et contrats en vigueur dans le canton de Genève. En cas de réussite à l’examen de fin d’apprentissage, les apprentis obtiennent le Certificat fédéral de capacité suisse (CFC). 6 places au total sont ouvertes au recrutement pour les deux professions. L’apprentissage dure 4 ans. Minima requis pour faire acte de candidature : avoir au moins 15 ans et moins de 21 ans à la date de début de l’apprentissage ; avoir terminé la scolarité obligatoire, au minimum 9e du Cycle d’orientation genevois (3e en France) ; être ressortissant d’un pays membre du CERN (Allemagne, Autriche, Belgique, Bulgarie, Danemark, Espagne, Finlande, France, Grèce, Hongrie, Italie, Norvège, Pays-Bas, Pologne, Portugal, Royaume-Uni, République tchèque, République slovaque , Suède, Suisse) ; pour les résidents en Suisse : être ressortissant su...

  2. Ultrasonic friction power during thermosonic Au and Cu ball bonding

    International Nuclear Information System (INIS)

    Shah, A; Mayer, M; Zhou, Y; Qin, I; Huynh, C; Meyer, M

    2010-01-01

    The ultrasonic friction power during thermosonic ball bonding with Au and Cu wires, both 25 μm in diameter, is derived with an improved method from experimental measurements during the bonding process. Experimental data include the current delivered to the ultrasonic transducer and the tangential force measured using piezoresistive microsensors integrated close to the Al bonding pad. The improvement results from a new, more accurate method to derive the mechanical compliance of the ultrasonic system. The method employs a bond process modification in which the ultrasonic current is ramped up sequentially in three steps. In the first two steps, the ultrasonic current is set to levels that are too low to cause sliding. The bonding takes place during the third step, when the current is ramped up to the optimum value required for making good quality bonds. The ultrasonic compliance values are derived from the first two steps and are 8.2 ± 0.5 μm N -1 and 7.7 ± 0.5 μm N -1 for the Au and Cu processes, respectively. These values are determined within an average error estimate of ±6%, substantially lower than the ±10% estimated with a previously reported method. The ultrasonic compliance in the case of Au is 6% higher due to the lower elastic modulus of Au compared with that of Cu. Typical maximum values of relative sliding amplitude of ultrasonic friction at the interface are 655 nm and 766 nm for the Au and Cu processes. These values are 81% of the free-air vibration amplitude of the bonding capillary tip for the respective ultrasonic current settings. Due to bond growth, which damps relative motion between the ball and the pad, the final relative amplitude at the bond interface is reduced to 4% of the equivalent free-air amplitude. Even though the maximum value of relative amplitude is 17% higher in the Cu process compared with the Au process, the average total interfacial sliding is 519 μm in the Cu process, which is 31% lower than that in the Au process (759

  3. Transverse velocity scaling in 197Au+197Au fragmentation

    International Nuclear Information System (INIS)

    Lukasik, J.; Hudan, S.; Lavaud, F.

    2002-07-01

    Invariant transverse-velocity spectra of intermediate-mass fragments were measured with the 4π multi-detector system INDRA for collisions of 197 Au on 197 Au at incident energies between 40 and 150 MeV per nucleon. Their scaling properties as a function of incident energy and atomic number Z are used to distinguish and characterize the emissions in (i) peripheral collisions at the projectile and target rapidities, and in (ii) central and (iii) peripheral collisions near mid-rapidity. The importance of dynamical effects is evident in all three cases and their origin is discussed. (orig.)

  4. Flow in Au+Au collisions at RHIC

    Science.gov (United States)

    Belt Tonjes, Marguerite; the PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2004-08-01

    The study of flow can provide information on the initial state dynamics and the degree of equilibration attained in heavy-ion collisions. This contribution presents results for both elliptic and directed flow as determined from data recorded by the PHOBOS experiment in Au+Au runs at RHIC at \\sqrt{sNN} = 19.6, 130 and 200 GeV. The PHOBOS detector provides a unique coverage in pseudorapidity for measuring flow at RHIC. The systematic dependence of flow on pseudorapidity, transverse momentum, centrality and energy is discussed.

  5. On the preferential crystallographic orientation of Au nanoparticles: Effect of electrodeposition time

    International Nuclear Information System (INIS)

    El-Deab, Mohamed S.

    2009-01-01

    The crystallographic orientation of Au nanoparticles electrodeposited at glassy carbon (nano-Au/GC) electrodes (prepared by potential step electrolysis) is markedly influenced by the width of the potential step. The oxygen reduction reaction (ORR) and the reductive desorption of cysteine have been studied on nano-Au/GC electrodes. Furthermore, electron backscatter diffraction (EBSD) technique has been used to probe the crystallographic orientation of the electrodeposited Au nanoparticles. That is, Au nanoparticles prepared in short time (5-60 s) have been found rich in the Au(1 1 1) facet orientation and are characterized by a relatively small particle size (ca. 10-50 nm) as well as high particle density (number of particles per unit area) as revealed by SEM images. Whereas Au nanoparticles prepared by longer electrolysis time (>60 s) are found to be much enriched in the Au(1 0 0) and Au(1 1 0) facets and are characterized by a relatively large particle size (>100 nm). EBSD patterns provided definitive information about the crystal orientations mapping of Au nanoparticles prepared at various deposition times.

  6. Preparation and study of dialkyl nitroxide radicals; Preparation et etude de radicaux nitroxydes diacyles

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [French] Ces radicaux sont obtenus par oxydation d'imides N-hydroxyles par le tetracetate de plomb ou l'acide p-nitroperbenzoique; ces imides sont prepares par chauffage d'anhydrides de diacides en presence de benzyloxyamine suivie d'une hydrogenation catalytique des N-benzyloxyimides ainsi obtenus. Deux series de radicaux ont principalement ete etudies: la premiere relative a des imides cycliques a cinq chainons, la seconde a des imides cycliques a six chainons, ces molecules ayant des substituants methyles ou non sur la chaine carbonee. Les derives O-benzyles de quelques-uns de ces imides ont ete analyses en R. M. N. Ces differents resultats ont permis une etude de la conformation et de la stereochimie de ces imides. (auteur)

  7. Preparation and study of dialkyl nitroxide radicals; Preparation et etude de radicaux nitroxydes diacyles

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [French] Ces radicaux sont obtenus par oxydation d'imides N-hydroxyles par le tetracetate de plomb ou l'acide p-nitroperbenzoique; ces imides sont prepares par chauffage d'anhydrides de diacides en presence de benzyloxyamine suivie d'une hydrogenation catalytique des N-benzyloxyimides ainsi obtenus. Deux series de radicaux ont principalement ete etudies: la premiere relative a des imides cycliques a cinq chainons, la seconde a des imides cycliques a six chainons, ces molecules ayant des substituants methyles ou non sur la chaine carbonee. Les derives O-benzyles de quelques-uns de ces imides ont ete analyses en R. M. N. Ces differents resultats ont permis une etude de la conformation et de la stereochimie de ces imides. (auteur)

  8. Event-plane-dependent dihadron correlations with harmonic vn subtraction in Au + Au collisions at s NN =200 GeV

    NARCIS (Netherlands)

    Agakishiev, H.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anderson, B. D.; Anson, C. D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Beavis, D. R.; Behera, N. K.; Bellwied, R.; Betancourt, M. J.; Betts, R. R.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Borowski, W.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bridgeman, A.; Brovko, S. G.; Bruna, E.; Bueltmann, S.; Bunzarov, I.; Burton, T. P.; Cai, X. Z.; Caines, H.; De La Barca Sánchez, M. Calderón; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, P.; Codrington, M. J M; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Dash, S.; Leyva, A. Davila; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Derevschikov, A. A.; De Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Efimov, L. G.; Elnimr, M.; Engelage, J.; Eppley, G.; Estienne, M.; Eun, L.; Evdokimov, O.; Fatemi, R.; Fedorisin, J.; Feng, A.; Fersch, R. G.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gangadharan, D. R.; Geromitsos, A.; Geurts, F.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Guertin, S. M.; Gupta, A.; Guryn, W.; Haag, B.; Hajkova, O.; Hamed, A.; Han, L. X.; Harris, J. W.; Hays-Wehle, J. P.; Heinz, M.; Heppelmann, S.; Hirsch, A.; Hjort, E.; Hoffmann, G. W.; Hofman, D. J.; Huang, B.; Huang, H. Z.; Humanic, T. J.; Huo, L.; Igo, G.; Jacobs, P.; Jacobs, W. W.; Jena, C.; Jin, F.; Joseph, J.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kauder, K.; Ke, H.; Keane, D.; Kechechyan, A.; Kettler, D.; Kikola, D. P.; Kiryluk, J.; Kisiel, A.; Kizka, V.; Knospe, A. G.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Krueger, K.; Krus, M.; Kumar, L.; Kurnadi, P.; Lamont, M. A C; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Leight, W.; Levine, M. J.; Li, C.; Li, L.; Li, N.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Lukashov, E. V.; Luo, X.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; Matulenko, Yu A.; McDonald, D.; McShane, T. S.; Meschanin, A.; Milner, R.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitrovski, M. K.; Mohanty, B.; Mondal, M. M.; Morozov, B.; Morozov, D. A.; Munhoz, M. G.; Naglis, M.; Nandi, B. K.; Nayak, T. K.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pei, H.; Peitzmann, T.; Perkins, C.; Peryt, W.; Phatak, S. C.; Pile, P.; Planinic, M.; Ploskon, M. A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V K S; Powell, C. B.; Prindle, D.; Pruthi, N. K.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Raniwala, R.; Raniwala, S.; Redwine, R.; Reed, R.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Ruan, L.; Rusnak, J.; Sahoo, N. R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmitz, N.; Schuster, T. R.; Seele, J.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D S; Staszak, D.; Steadman, S. G.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A P; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J M; De Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarini, L. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Tram, V. N.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; Van Nieuwenhuizen, G.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M S; Vasiliev, A. N.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Q.; Wang, X. L.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Whitten, C.; Wieman, H.; Wissink, S. W.; Witt, R.; Witzke, W.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xu, H.; Xu, N.; Xu, Q. H.; Xu, W.; Xu, Y.; Xu, Z.; Xue, L.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, I. K.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, J. B.; Zhang, S.; Zhang, W. M.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, J.; Zhong, C.; Zhou, W.; Zhu, X.; Zhu, Y. H.; Zoulkarneev, R.; Zoulkarneeva, Y.

    2014-01-01

    STAR measurements of dihadron azimuthal correlations (Δφ) are reported in midcentral (20-60%) Au+Au collisions at sNN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane, φs=|φt-ψEP|. The elliptic (v2), triangular (v3), and quadratic (v4) flow harmonic

  9. Study of the inclusive production of {phi}{sup 0} mesons and measurement of the branching ratio of the Z{sup 0} bosons into strange quarks pairs with the DELPHI detector at LEP; Etude de la production inclusive de mesons {phi}{sup 0} et mesure du rapport d`embranchement du boson Z{sup 0} en paires de quarks etranges aupres de l`experience DELPHI au LEP

    Energy Technology Data Exchange (ETDEWEB)

    Pages, P

    1996-05-07

    The thesis work is relative to an analysis of data collected by the DELPHI detector at LET in 1992 and 1993, in order to study the inclusive production production of {phi}{sup 0} mesons, reconstructed according to the decay mode {phi}{sup 0} {yields} K{sup +}K{sup -}. The kaon identification, indispensable to do this reconstruction, was made by the Barrel RICH detector of DELPHI. This study was first done to test the {phi}{sup 0} production in the Lund string model, which is one of the models used to describe the production of hadrons in the e{sup +}e{sup -}processes. The experimental distribution of the differential cross section of the inclusive {phi}{sup 0} production was compared to the one predicted by the model and indicates that the model well reproduces the experimental data. The mean number of produced {phi}{sup 0} per hadronic event was found to be: 0.091 {+-} 0.013, in good agreement with the expected value: 0.091. Next, high momentum {phi}{sup 0} mesons were used for a measurement of the branching ratio of the Z{sup 0} bosons into strange quark pairs: {Gamma}{sub ss}-bar/{Gamma}{sub had}. Three {phi}{sup 0} mesons samples were selected, for which the purity in Z{sup 0}{yields} ss-bar events was greater than 60, 70 and 80 %. For each of these 3 samples, the obtained experimental values are respectively: 0.16 {+-} 0.04, 0.13{+-}0.04 et 0.12{+-}0.05. These values show relatively large uncertainties and indicate an agreement of at the most 2.6 standard deviations to the expected value: 0.22. (author). 63 refs.

  10. Chiral magnetic effect search in p+Au, d+Au and Au+Au collisions at RHIC

    Science.gov (United States)

    Zhao, Jie

    2018-01-01

    Metastable domains of fluctuating topological charges can change the chirality of quarks and induce local parity violation in quantum chromodynamics. This can lead to observable charge separation along the direction of the strong magnetic field produced by spectator protons in relativistic heavy-ion collisions, a phenomenon called the chiral magnetic effect (CME). A major background source for CME measurements using the charge-dependent azimuthal correlator (Δϒ) is the intrinsic particle correlations (such as resonance decays) coupled with the azimuthal elliptical anisotropy (v2). In heavy-ion collisions, the magnetic field direction and event plane angle are correlated, thus the CME and the v2-induced background are entangled. In this report, we present two studies from STAR to shed further lights on the background issue. (1) The Δϒ should be all background in small system p+Au and d+Au collisions, because the event plane angles are dominated by geometry fluctuations uncorrelated to the magnetic field direction. However, significant Δϒ is observed, comparable to the peripheral Au+Au data, suggesting a background dominance in the latter, and likely also in the mid-central Au+Au collisions where the multiplicity and v2 scaled correlator is similar. (2) A new approach is devised to study Δϒ as a function of the particle pair invariant mass (minv) to identify the resonance backgrounds and hence to extract the possible CME signal. Signal is consistent with zero within uncertainties at high minv. Signal at low minv, extracted from a two-component model assuming smooth mass dependence, is consistent with zero within uncertainties.

  11. Filipino au pairs on the move

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2016-01-01

    Most Filipina au pairs in Denmark send remittances back home, and for many, au pairing forms part of longer-term migration trajectories. This article explores how Filipina au pairs try to carve out a future for themselves abroad. It shows that they navigate within tight webs of financial interdep......Most Filipina au pairs in Denmark send remittances back home, and for many, au pairing forms part of longer-term migration trajectories. This article explores how Filipina au pairs try to carve out a future for themselves abroad. It shows that they navigate within tight webs of financial...

  12. Level lifetimes of Au52+ in Au plasma

    International Nuclear Information System (INIS)

    Liu Bo; Zhu Zhiyan; Jiang Gang; Zhu Zhenghe

    2003-01-01

    Based on the extended relativistic multiconfiguration Dirac-Fock theory, the level lifetimes, level widths and wavelengths of Au 52+ have been calculated using the General-purpose Relativistic Atomic Structure Program. The wavelengths obtained are in good agreement with the experimental data available. The relationship between the level lifetimes and the level widths satisfies the Heisenberg uncertainty principle

  13. Hydrothermal oxidation of an epoxy resin through the study of two model molecules: N-methyl-acetamide and N,N-di[1(phenoxy)2-hydroxy propyl-3] propyl-amine; Oxydation hydrothermale d'une resine epoxyde au travers de l'etude de deux molecules modeles: le N-methylacetamide et la N,N-di[1-(phenoxy) 2-hydroxy propyl-3] propylamine

    Energy Technology Data Exchange (ETDEWEB)

    Moutonnet-Fromonteil, C. [CEA/Cadarache, Dept. d' Etudes des Combustibles (DEC), 13 - Saint-Paul-lez-Durance (France)]|[Bordeaux-1 Univ., 33 (France)

    2000-07-01

    The study consists in choosing and developing a technology to realize damage experiments of an epoxy resin which is used as coating of embedded nuclear samples. Hydrothermal oxidation is the chosen method. We first identified the chemical composition of the epoxy resin. Then we studied hydrolysis and oxidation of a molecule which contains a function of the epoxy network: N-methyl-acetamide. The comparison between our results and those already existing allowed to validate this degradation method. In a second part, we studied a model molecule of the polymer network: N, N-di[1(phenoxy)2-hydroxy propyl-3] propyl-amine. The hydrolysis temperatures are relatively high: the compound is totally destroyed at 300 deg C. Its oxidation leads to the formation of acetic acid from 220 deg C. In the third study, we determined the best experimental conditions to destroy the epoxy resin. Experiments were performed at different temperatures between 200 deg C and 410 deg C. The degradation rates are classically defined by amounts of constituents in liquid and gaseous phases. (author)

  14. Blowing loop in the EL-4 reactor: CO{sub 2} flow control analogue study; Boucle de soufflage de la centrale EL-4 - regulation du debit CO{sub 2} - etude analogique

    Energy Technology Data Exchange (ETDEWEB)

    Chazal, G; Merle, J P; Guillemard, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Leroy, C; Robin, L; Jacquin, J C; Cornudet, A [Societe INDATOM, France (France)

    1966-07-01

    naturel du systeme en l'absence de regulation. determination theorique des elements de regulation; mise au point de la regulation sur calculateur analogique et deuxieme campagne d'essais pour enregistrer les performances de la boucle de soufflage. La 4. partie du rapport traite de l'etude analogique: equations analogiques - mise au point. (auteurs)

  15. Spectra of identified particles, geometry categorization and bias and global observables in d+Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Sarah

    2014-11-15

    Geometry selection in d+Au/p+Pb collisions is crucial for understanding the physics underlying modified nuclear parton distribution functions, gluon saturation or shadowing, initial state energy loss, and possible hydrodynamic flow in these small systems. The PHENIX Collaboration tests for auto-correlation biases in the geometry determination in small collision systems. These biases are well understood and an order of magnitude smaller at RHIC as compared to the LHC. As a result, auto-correlation biases are unable to describe the suppression of high transverse momentum (p{sub T}) π{sup 0}'s seen in the ratio of central-to-peripheral d+Au collisions. The centrality dependent d+Au pion, kaon and proton yields relative to binary collision-scaled p+p yields are also reported, including the high p{sub T}π{sup 0} and K{sub S}{sup 0}. At intermediate p{sub T}, between 2and5GeV/c, baryons are enhanced in central d+Au collisions. The baryon enhancement is present in d+Au and Au+Au collisions and increases with centrality. We compare identified particle yields in peripheral Au+Au collisions to central d+Au collisions that have a comparable number of participants and binary collisions. The p{sub T} dependence of this ratio is strikingly similar for mesons and baryons.

  16. Morphological Characteristics of Au Films Deposited on Ti: A Combined SEM-AFM Study

    Directory of Open Access Journals (Sweden)

    Francesco Ruffino

    2018-03-01

    Full Text Available Deposited Au films and coatings are, nowadays, routinely used as active or passive elements in several innovative electronic, optoelectronic, sensing, and energy devices. In these devices, the physical properties of the Au films are strongly determined by the films nanoscale structure. In addition, in these devices, often, a layer of Ti is employed to promote adhesion and, so, influencing the nanoscale structure of the deposited Au film. In this work, we present experimental analysis on the nanoscale cross-section and surface morphology of Au films deposited on Ti. In particular, we sputter-deposited thick (>100 nm thickness Au films on Ti foils and we used Scanning Electron Microscopy to analyze the films cross-sectional and surface morphology as a function of the Au film thickness and deposition angle. In addition, we analyzed the Au films surface morphology by Atomic Force Microscopy which allowed quantifying the films surface roughness versus the film thickness and deposition angle. The results establish a relation between the Au films cross-sectional and surface morphologies and surface roughness to the film thickness and deposition angle. These results allow setting a general working framework to obtain Au films on Ti with specific morphological and topographic properties for desired applications in which the Ti adhesion layer is needed for Au.

  17. Etude de l'analyse de la distribution de crédits aux entreprises Etude de cas : La B.E.A.

    OpenAIRE

    Berrahi, kheir-eddine

    2014-01-01

    le premier chapitre présente l'orgainsme d'acceuil la banque exterieure d'Algérie et les typologies des crédits existants au sein de la banque.Le deuxiéme chapitre sera consacré au marketing bancaire et le rôle qui tient à l'économie Algérienne.le troisiéme chapitre sera consacré à la relation avec la clientéle et à la distribution bancaire.le dernier chapitre portera respectivement sur le diagnostic externe et interne de l'environnement de la banque, puis analysera les différents produits ...

  18. Le recours aux modeles dans l'enseignement de la biologie au secondaire : Conceptions d'enseignantes et d'enseignants et modes d'utilisation

    Science.gov (United States)

    Varlet, Madeleine

    Le recours aux modeles et a la modelisation est mentionne dans la documentation scientifique comme un moyen de favoriser la mise en oeuvre de pratiques d'enseignement-apprentissage constructivistes pour pallier les difficultes d'apprentissage en sciences. L'etude prealable du rapport des enseignantes et des enseignants aux modeles et a la modelisation est alors pertinente pour comprendre leurs pratiques d'enseignement et identifier des elements dont la prise en compte dans les formations initiale et disciplinaire peut contribuer au developpement d'un enseignement constructiviste des sciences. Plusieurs recherches ont porte sur ces conceptions sans faire de distinction selon les matieres enseignees, telles la physique, la chimie ou la biologie, alors que les modeles ne sont pas forcement utilises ou compris de la meme maniere dans ces differentes disciplines. Notre recherche s'est interessee aux conceptions d'enseignantes et d'enseignants de biologie au secondaire au sujet des modeles scientifiques, de quelques formes de representations de ces modeles ainsi que de leurs modes d'utilisation en classe. Les resultats, que nous avons obtenus au moyen d'une serie d'entrevues semi-dirigees, indiquent que globalement leurs conceptions au sujet des modeles sont compatibles avec celle scientifiquement admise, mais varient quant aux formes de representations des modeles. L'examen de ces conceptions temoigne d'une connaissance limitee des modeles et variable selon la matiere enseignee. Le niveau d'etudes, la formation prealable, l'experience en enseignement et un possible cloisonnement des matieres pourraient expliquer les differentes conceptions identifiees. En outre, des difficultes temporelles, conceptuelles et techniques peuvent freiner leurs tentatives de modelisation avec les eleves. Toutefois, nos resultats accreditent l'hypothese que les conceptions des enseignantes et des enseignants eux-memes au sujet des modeles, de leurs formes de representation et de leur approche

  19. Plasmonic enhancement of visible-light water splitting with Au-TiO2 composite aerogels

    Science.gov (United States)

    Desario, Paul A.; Pietron, Jeremy J.; Devantier, Devyn E.; Brintlinger, Todd H.; Stroud, Rhonda M.; Rolison, Debra R.

    2013-08-01

    We demonstrate plasmonic enhancement of visible-light-driven splitting of water at three-dimensionally (3D) networked gold-titania (Au-TiO2) aerogels. The sol-gel-derived ultraporous composite nanoarchitecture, which contains 1 to 8.5 wt% Au nanoparticles and titania in the anatase form, retains the high surface area and mesoporosity of unmodified TiO2 aerogels and maintains stable dispersion of the ~5 nm Au guests. A broad surface plasmon resonance (SPR) feature centered at ~550 nm is present for the Au-TiO2 aerogels, but not Au-free TiO2 aerogels, and spans a wide range of the visible spectrum. Gold-derived SPR in Au-TiO2 aerogels cast as films on transparent electrodes drives photoelectrochemical oxidation of aqueous hydroxide and extends the photocatalytic activity of TiO2 from the ultraviolet region to visible wavelengths exceeding 700 nm. Films of Au-TiO2 aerogels in which Au nanoparticles are deposited on pre-formed TiO2 aerogels by a deposition-precipitation method (DP Au/TiO2) also photoelectrochemically oxidize aqueous hydroxide, but less efficiently than 3D Au-TiO2, despite having an essentially identical Au nanoparticle weight fraction and size distribution. For example, 3D Au-TiO2 containing 1 wt% Au is as active as DP Au/TiO2 with 4 wt% Au. The higher photocatalytic activity of 3D Au-TiO2 derives only in part from its ability to retain the surface area and porosity of unmodified TiO2 aerogel. The magnitude of improvement indicates that in the 3D arrangement either a more accessible photoelectrochemical reaction interphase (three-phase boundary) exists or more efficient conversion of excited surface plasmons into charge carriers occurs, thereby amplifying reactivity over DP Au/TiO2. The difference in photocatalytic efficiency between the two forms of Au-TiO2 demonstrates the importance of defining the structure of Au||TiO2 interfaces within catalytic Au-TiO2 nanoarchitectures.We demonstrate plasmonic enhancement of visible-light-driven splitting of

  20. La course au logement social

    OpenAIRE

    Bourgeois, Marine

    2013-01-01

    Ce billet a été publié dans le cadre de l'opération Têtes Chercheuses, qui permet à des étudiants ou chercheurs de grandes écoles, d'universités ou de centres de recherche partenaires de promouvoir des projets innovants en les rendant accessibles, et ainsi participer au débat public.

  1. The use of tracers in the study of the ionic permeability of the nerve; Utilisation des indicateurs nucleaires dans l'etude de la permeabilite ionique du nerf

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-07-01

    The use of the radioactive tracers {sup 24}Na and {sup 42}K, and the electrophysiological fine study carried out on the plant Cephalopods nervous cells have made it possible, during ten years, to study the relationships between the electrical phenomena observed during the propagation of the nervous impulse and the ionic movements which occur at the cell membrane between the intra- and extra-cellular media. In the state of rest, the nerve fibres present a certain permeability towards sodium and potassium, a permeability which allows the renewal, from the extra-cellular medium, of the cations contained in the cytoplasm. At the moment of the passage of the nervous impulse, it is possible to demonstrate a temporary increase in the permeability towards the sodium which causes the entry of Na{sup +} ions into the nerve fibre, whilst, a few milliseconds later, the increase in the potassium permeability causes the departure of an equivalent quantity of K{sup +} ions. A recovery phase follows the passage of the nervous impulse, during which the original ionic conditions are re-established. If the potassium movements can be considered as passive, the expulsion of Na{sup +} requires, on the part of the cell, the use of a part of the metabolic energy. (author) [French] L'utilisation des indicateurs radioactifs {sup 24}Na et {sup 42}K, et l'etude electrophysiologique fine realisee sur des cellules nerveuses geantes de Cephalopodes a permis, depuis une dizaine d'annees, d'etudier les rapports entre les phenomenes electriques observes lors de la propagation de l'influx nerveux et les mouvements ioniques qui s'effectuent au niveau de la membrane cellulaire entre milieux intracellulaire et extracellulaire. A l'etat de repos, les fibres nerveuses possedent pour le sodium et le potassium, une permeabilite qui permet le renouvellement, a partir du milieu extracellulaire des cations contenus dans le cytoplasme. Au moment du passage de l'influx nerveux, on peut mettre en evidence une

  2. Composes inter-halogenes sous pression: etude des transformations structurales dans le monobromure d'iode sous forme dense

    Science.gov (United States)

    Bouchard, Alexandre

    La famille des composes halogenes et inter-halogenes representent des solides moleculaires adoptant des phases denses communes avec des solides moleculaires diatomiques comme l'azote et l'hydrogene. Parmi les transformations structurales et electroniques induites sous haute pression et observees dans ces solides, on note, entre autres, la dissociation moleculaire et la metallisation. De plus, l'etude des phases denses de l'iode a permis recemment l'observation d'une structure cristalline possedant une modulation dite incommensurable, c'est-a-dire une modulation possedant une periodicite differente de celle de la structure cristalline, jetant ainsi une lumiere nouvelle sur le processus de dissociation moleculaire dans les solides halogenes. Dans ce memoire, on propose d'etudier les changements structuraux dans monobromure d'iode (IBr), un compose inter-halogene possedant des proprietes structurales semblables a celles de deux composes halogenes, soit l'iode (I 2) et le brome (Br2) sous leur forme solide. Des experiences de diffraction des rayons X de poudres en utilisant un rayonnement synchrotron ont ete realisees a temperature ambiante sur l'IBr en variant la pression jusqu'aux environs de 60 GPa. La nature chimique particuliere du compose IBr a necessite la mise au point de techniques de chargement d'echantillon destinees a preserver l'integrite chimique de la substance utilisee. On rapporte egalement l'observation d'une phase de l'IBr presentant une modulation incommensurable. Les phases observees dans l'IBr permettent d'etablir des paralleles avec les phases denses rapportees dans I2 et Br2 par le biais d'un modele phenomenologique decrivant la sequence structurale des solides halogenes sous forme condensee.

  3. Study of superconducting Nb{sub 3}Sn coils; Etude de bobinages supraconducteurs en Nb{sub 3}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Vivet, B

    1963-07-01

    Composite superconducting Nb{sub 3}Sn wires with a diameter of 0.5 mm and a length of about 100 m were made, and Hc-Ic diagrams were plotted up to fields of 80 kgauss for short lengths. Two solenoids producing fields of about 20 kgauss were studied. Nb{sub 3}Sn solenoids, as opposed to those of Nb-Zr or Nb-Ti, appear to have a predictable behavior. Solenoids with less insulation produced stronger fields than heavily insulated solenoids. (author) [French] Une etude des fils composites supraconducteurs de Nb{sub 3}Sn a ete entreprise au C.E.N. Saclay, en collaboration avec la Societe S.O.D.E.R.X. Des fils de 0,5 mm de diametre et d'une centaine de metres de longueur ont ete produits de facon experimentale. Des diagrammes Hc-Ic ont pu etre traces, jusqu'en des champs de 80 kG, sur des echantillons de petite longueur. Deux solenoides ont ete etudies produisant les champs de l'ordre de 20 kg. Il semble que, contrairement aux alliages Nb-Zr ou Nb-Ti, les solenoides en Nb{sub 3}Sn aient un comportement previsible d'apres les tests sur des echantillons courts. On montrera d'autre part qu'un bobinage a faible isolement peut produire un champ notablement plus eleve qu'un bobinage isole. Une production plus extensive permettra, dans les semaines a venir, la fabrication de solenoides de plus grosse dimension et produisant des champs plus eleves. (auteur)

  4. Recent research on the pharmaceutical checking of radioelements (1961); Etudes recentes sur le controle pharmaceutique des radioelements (1961)

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    Checking on radioactive preparations for medical use is complicated by difficulties due to the radioactivity, the instability and the methods of using these solutions. In effect it is necessary, in order to draw up a practicable set of rules governing such checks, to know both the method of preparation and the properties of the radioelement, as well as special and often contradictory features of its use. These tests fall into three categories: physical, chemical and biological. Preparations of chromium 51, iron 59 and arsenic 76 have been dealt with in recent studies. In each case special tests were necessary, and these will be described in this paper. The practice of these tests is of twofold interest: firstly they provide a maximum guarantee to the user, and secondly they guide the chemist in his manipulations, immediately and thoroughly. (author) [French] Le controle des preparations radioactives a usage medical est complexe par suite des difficultees dues a la radioactivite, a l'instabilite et aux modalites d'utilisation de ces solutions. En effet, l'etablissement justifie d'un protocole de controle necessite la connaissance aussi bien du mode de preparation, que des proprietes du radioelement et des particularites parfois contradictoires de son emploi. Ces controles sont de trois ordres physiques, chimiques, biologiques. Des etudes recentes ont porte sur des preparations de chrome 51, de fer 59, d'arsenic 76. Dans chaque cas, il est apparu necessaire de pratiquer des controles particuliers qui seront exposes dans la communication. La pratique de ces derniers presente un double interet; d'une part, ils assurent a l'utilisateur un maximum de garantie, d'autre part, ils orientent le chimiste dans ses mises au point, immediatement et de facon approfondie. (auteur)

  5. Pegase: safety studies - experimental study of burn-out risks in transient operation; Pegase: etude de surete - etude experimentale des risques de burn out en regime transitoire

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-07-01

    canal chaud se met en etat de calefaction au bout de 0.1 s et que sa temperature atteint 500 C en 0.8 s. Les regimes hydrodynamiques rencontres dans les canaux apres l'accident sont des regimes d'expulsion periodiques de periodes courtes 0.2 a 0.5 s, caracteristiques de l'ebullition a basse pression. L'etude en regime permanent de la redistribution de debit dans un by-pass a donne des flux PHI{sub R} de redistribution de 190 W/cm{sup 2} pour une vitesse de 4.5 m/s a 50 C et de 175 W/cm{sup 2} a 60 C. Ces valeurs sont a majorer de 25 pour cent pour une vitesse de 6 m/s. On a montre la distinction a faire entre flux critique PHI{sub C} en regime periodique d'expulsion et flux de redistribution PHI{sub R} en regime permanent. (auteur)

  6. Atomistic Simulations of Functional Au-144(SR)(60) Gold Nanoparticles in Aqueous Environment

    DEFF Research Database (Denmark)

    Heikkila, E.; Gurtovenko, A. A.; Martinez-Seara, H.

    2012-01-01

    and Cl-/Na+ counterions, respectively. The radial distribution functions show that the side chains and terminal groups show significant flexibility. The orientation of water is distinct in the first solvation shell, and AuNPs cause a long-range effect in the solvent structure. The radial electrostatic...... of the nanoparticle together with surrounding ions and water. We focus on Au-144 nanoparticles that comprise a nearly spherical Au core (diameter similar to 2 nm), a passivating Au-S interface, and functionalized alkanethiol chains. Cationic and anionic AuNPs have been modeled with amine and carboxyl terminal groups...... in aqueous solutions. They suggest that electrostatics is one of the central factors in complexation of AuNPs with other nanomaterials and biological systems, and that effects of electrostatics as water-mediated interactions are relatively long-ranged, which likely plays a role in, e.g., the interplay...

  7. Centrality determination in Au-Au collisions at 1.23 AGeV with HADES

    Energy Technology Data Exchange (ETDEWEB)

    Zuschke, Maximilian [Institut fuer Kernphysik, Goethe-Universitaet Frankfurt (Germany); Collaboration: HADES-Collaboration

    2016-07-01

    An important characterization of events in heavy-ion physics is the centrality. It classifies events by considering the collision's cross section relative to the total cross section of the system. This characteristics is needed for many analyses, as it provides indirect information about the initial geometrical reaction properties. As the production rate of particles is a function of the deposited energy, which itself depends on the centrality, quantities based on measured multiplicities allow to draw conclusions about the centrality of a collision. Estimators used to determine the centrality for Au-Au collisions at 1.23 AGeV recorded with HADES include the charged particle multiplicity and hit multiplicities measured with various detectors, such as the TOF/RPC or forward wall. Calibration methods accounting for variations in the acceptance of the detectors are introduced and verified by comparison with the theoretical expectations, as obtained by calculations with the Glauber-Model.

  8. On Productions of Net-Baryons in Central Au-Au Collisions at RHIC Energies

    Directory of Open Access Journals (Sweden)

    Ya-Hui Chen

    2015-01-01

    Full Text Available The transverse momentum and rapidity distributions of net-baryons (baryons minus antibaryons produced in central gold-gold (Au-Au collisions at 62.4 and 200 GeV are analyzed in the framework of a multisource thermal model. Each source in the model is described by the Tsallis statistics to extract the effective temperature and entropy index from the transverse momentum distribution. The two parameters are used as input to describe the rapidity distribution and to extract the rapidity shift and contribution ratio. Then, the four types of parameters are used to structure some scatter plots of the considered particles in some three-dimensional (3D spaces at the stage of kinetic freeze-out, which are expected to show different characteristics for different particles and processes. The related methodology can be used in the analyses of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

  9. Evaluation of three algorithms to calculate the relative renal function with {sup 99}Tc-DTPA; Evaluation de trois algorithmes pour calculer la fonction renale relative au {sup 99}Tc-DTPA

    Energy Technology Data Exchange (ETDEWEB)

    Charfeddine, S.; Maaloul, M.; Kallel, F.; Chtourou, K.; Guermazi, F. [EPS Habib Bourguiba, Service de Medecine Nucleaire, Sfax (Tunisia)

    2006-06-15

    The aim of our study is to estimate the reproducibility and the exactitude of three algorithms to determine with {sup 99m}Tc-DTPA the relative function of each kidney. Methods: a prospective study was carried out in voluntary patients. Reproducibility was studied in 11 patients who underwent had two examinations with {sup 99m}Tc-DTPA. Exactitude was evaluated in 35 patients who had an additional scintigraphy with {sup 99m}Tc-DMSA taken as a reference. To determine the relative renal function with {sup 99m}Tc-DTPA, three algorithms using various background subtraction methods and time intervals were applied. Results and conclusion: the method of the integral was the most reproducible and exact. It was little influenced by the choice of the interval of time. The reproducibility and the exactitude of the Patlak method were worse, especially in case of renal insufficiency or hydronephrosis. A high background and poor counting statistics explain why Patlak was less powerful with {sup 99m}Tc-DTPA than with {sup 99m}Tc-MAG3. The method of the slopes should not be recommended any more. (author)

  10. Bringing migrant domestic work literature into family studies: the intricate dynamics of au pair families

    OpenAIRE

    Pelechova, Lenka

    2014-01-01

    This thesis explores families with live in au pairs. In particular, it investigates the changes that families go through as a result of the addition of an au pair, as well as the means by which the host parents and au pairs negotiate their new circumstances of living and working together. \\ud From a theoretical perspective, the thesis is positioned between two bodies of literature, namely, those of migrant domestic work and family studies. Up until now, research conducted in relation to au pa...

  11. Contribution towards the study of {beta}{yields}{alpha} transformation in uranium and its alloys (1962); Contribution a l'etude de la transformation {beta}{yields}{alpha} dans l'uranium et ses alliages (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-05-15

    The kinetics of the transformation of uranium alloys containing 0.5 - 0.75 - 1.0 - 1.5 and 3 atoms per cent have been studied. The influence of heat treatment before decomposition has been discussed. The study of the transformation characteristics such as kinetics, residual phases, phenomena connected with the coherence between phases, reversibility below the equilibrium temperature, shows the following mechanisms exhibited during the decomposition of the {beta} phase on lowering the temperature: 1 ) eutectoid, 2) bainitic, 3) martensitic. The study of the TTT diagrams of alloys containing decreasing percentages of chromium indicates that the unalloyed uranium transforms without maintaining the coherence above 600 deg. C, where as at lower temperatures the transformation is mainly martensitic. The various alloying elements can be characterised by their influence on the three TTT curves corresponding to the three possible transformation mechanisms. The ability of the uranium alloys to alpha grain refining during isothermal decomposition or ambient temperature quenching is directly connected with the characteristics of the TTT diagrams and especially to the mode of bainitic transformation. (author) [French] II a ete etudie la cinetique de transformation des alliages uranium-chrome de teneur 0,5 - 0,75 - 1 - 1,5 - et 3 atomes pour cent. L'influence des traitements thermiques precedant la decomposition a ete discutee. L'etude des caracteristiques de la transformation: cinetique, phases residuelles, phenomenes lies a la coherence entre phases, reversibilite au-dessous de la temperature d'equilibre, permet de conclure que la decomposition met en jeu successivement les trois mecanismes eutectoide, bainitique et martensitique quand la temperature baisse. L'etude de l'evolution des diagrammes TTT quand la teneur en Cr decroit indique que dans l'uranium non allie la transformation se fait sans maintien de la coherence au-dessus de 600 deg. C; a

  12. Contribution towards the study of {beta}{yields}{alpha} transformation in uranium and its alloys (1962); Contribution a l'etude de la transformation {beta}{yields}{alpha} dans l'uranium et ses alliages (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-05-15

    The kinetics of the transformation of uranium alloys containing 0.5 - 0.75 - 1.0 - 1.5 and 3 atoms per cent have been studied. The influence of heat treatment before decomposition has been discussed. The study of the transformation characteristics such as kinetics, residual phases, phenomena connected with the coherence between phases, reversibility below the equilibrium temperature, shows the following mechanisms exhibited during the decomposition of the {beta} phase on lowering the temperature: 1 ) eutectoid, 2) bainitic, 3) martensitic. The study of the TTT diagrams of alloys containing decreasing percentages of chromium indicates that the unalloyed uranium transforms without maintaining the coherence above 600 deg. C, where as at lower temperatures the transformation is mainly martensitic. The various alloying elements can be characterised by their influence on the three TTT curves corresponding to the three possible transformation mechanisms. The ability of the uranium alloys to alpha grain refining during isothermal decomposition or ambient temperature quenching is directly connected with the characteristics of the TTT diagrams and especially to the mode of bainitic transformation. (author) [French] II a ete etudie la cinetique de transformation des alliages uranium-chrome de teneur 0,5 - 0,75 - 1 - 1,5 - et 3 atomes pour cent. L'influence des traitements thermiques precedant la decomposition a ete discutee. L'etude des caracteristiques de la transformation: cinetique, phases residuelles, phenomenes lies a la coherence entre phases, reversibilite au-dessous de la temperature d'equilibre, permet de conclure que la decomposition met en jeu successivement les trois mecanismes eutectoide, bainitique et martensitique quand la temperature baisse. L'etude de l'evolution des diagrammes TTT quand la teneur en Cr decroit indique que dans l'uranium non allie la transformation se fait sans maintien de la coherence au-dessus de 600 deg. C; a plus basse temperature la

  13. Study of the age of uranium-containing mineral deposits in the Limouzat, the bois-noir mountains (12963); Etude des ages des mineralisations uraniferes du gisement du Limouzat, Massif des bois-noirs (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

    The present work is concerned with 7 different samples taken at various levels in the Limouzat mine in the Bois-Noirs mountains. It has been possible to show that the uranium dates from 265 M.Y. and that a rearrangement occurred 65 M.Y. ago. A {gamma}-spectrometer study which was originally intended to show the existence of the lack of balance in the radon circulation, has made it possible to show that the {gamma} spectra recorded on various samples could be erroneous. We observed in effect that the presence of lead, iron, etc., had a strong influence on the {gamma} spectrum of the radium family, whereas all research workers have considered that concentrations in the uranium ore were negligible and had no significant effect on the study of the {gamma} spectra of the samples. It is obvious that an interesting study has to be undertaken on the screen effects of the different cations existing in the ores. We believe that it is possible to show the presence of certain elements directly by {gamma}-spectrometry. The ages measured with the mass spectrometer present two types of disagreement but these have been explained by considering that there occurred a first arrival of lead followed by a rearrangement and, at certain points, a second arrival at this date. Finally, the deposit studied undergoes a circulation of uranium and of radon. (author) [French] La presente etude a porte sur 7 prelevements differents effectues a divers niveaux de la mine du Limouzat, massif des Bois-Noirs. Elle a permis de mettre en evidence une premiere venue d'uranium il y a 265 M.A., suivie d'un remaniements il y a 65 M.A. Une etude au spectrometre {gamma} destinee, a l'origine, a prouver les desequilibres dus aux circulations de radon a permis de montrer que les spectres {gamma} enregistres sur divers echantillons pouvaient etre entaches d'erreurs. Nous nous sommes apercus en effet que la presence de plomb, de fer..., avait une forte influence sur le spectre {gamma} de la famille du radium

  14. Etude comparative de la rentabilité de deux types d'apiculture au Nord Ouest Cameroun

    Directory of Open Access Journals (Sweden)

    Tsafack Matsop, AS.

    2011-01-01

    Full Text Available Comparative Study of the Profitability of Two Types of Bee Farming in the North West Cameroon. The present study examines the financial profitability of beekeeping in Cameroon. The global objective is to compare the profitability of two types of bee farms in the North West Region. The main hypothesis, however, is the following: there is a significant difference in output and in net benefit between traditional and semimodern bee farms. As regards the methodology used, a two stage stratified random sampling technique was used to select 100 bee farmers. Primary data was collected on elements of costs and revenue. The technique of cost benefit analysis was used to analyze the data. Findings showed that traditional beekeeping and semi-modern beekeeping (using Kenyan hives "KTBH" farms have an average production of 77.46 and 112.68 liters of honey per year respectively, for the respective average total revenue of 86 832.39 FCFA and 143 791 FCFA. The average annual value of their ratio Net Benefit/Total Cost is 1.168 and 1.193 respectively. The semi-modern bee hives perform better than the traditional one. Even with some difficulties faced by some farmers, bee farming in the North West Cameroon remains profitable. Despite the static character of this study, we suggest that beekeepers should adopt the semi-modern (Kenyan hives.

  15. Study of dimuons in Nomad experience at the CERN; Etude des dimuons dans l`experience Nomad au CERN

    Energy Technology Data Exchange (ETDEWEB)

    Vo, M K

    1996-06-04

    This thesis concerns the study of the production of the first dimuons events in the NOMAD experience (Neutrino Oscillation MAgnetic Detector). This study is necessary to improve our knowledge about the charmed quark and allows to secure ourselves about the well functioning of our detector and about the reliability of our analysis tools. The two first chapters concern the understanding of physical phenomenons. The physic of neutrinos is described, known and unknown, with a lot of open questions. The second chapter, more specially, gives a theoretical and experimental look concerning the production of dimuons by the neutrinos; the chapter three is devoted to the presentation of the NOMAD detector and its characteristics. The chapter number four concerns the method used by the NOMAD collaboration (drift chambers and their functioning); the chapter five is devoted to the muons identification; the data selection is described at the chapter six; a first preliminary oscillation analysis is studied in the chapter seven; the conclusion ends on questions to deepen the entered upon studies in this thesis. (N.C.). 78 refs., 77 figs., 24 tabs.

  16. Etude exploratoire de la commercialisation des nanotechnologies au Canada: L'utilisation de la fouille de donnees de contenu Web

    Science.gov (United States)

    Rietsch, Constant

    Companies rely more every day on the Internet, sharing a lot of information to their customers but also their investors and their associates. Most companies share information such as products, services, partnerships, and research and development activities on their website. All this information is much analytical opportunities provided that we can retrieve and interpret. In this context, is the content of a website can be enough to conduct a study on innovation and commercialization? Websites are sources of information available and accessible to everyone. The majority of companies with a website, the coverage of an Internet-based study is an advantage. For our research on the commercialization of nanotechnology in Canada, we recover as many data on websites of Canadian companies listed by various sources as having activities in nanotechnology. From these data we cluster companies according to their nanotechnology field using a list of keywords from scientific papers to estimate the level of advancement of Canadian companies in nanotechnology research. Finally thanks to several indicators of innovation and marketing we describe the current state of nanotechnology in the Canadian industry.

  17. Etude bactériologique et biochimique du miel vendu au marché central de Bukavu (Congo

    Directory of Open Access Journals (Sweden)

    Kitambala, K.

    1999-01-01

    Full Text Available Bacteriological and Biochemical Study of Honey Sold at Bukavu (Congo Central Market. The honey sold in the central market of Bukavu (Congo is produced by traditional bee keepers. This article deals with a bacteriological and biochemical study of this product in order to determine its contamination and pollution levels. Results indicated a contamination of faecal origin (presence of enterobacteria such as Escherichia coli. The bacteriological tests showed the presence of bacteria fermenting glucose, thus altering the quality of the honey. The latter is therefore inappropriate for consumption and constitutes a danger for the health of humans.

  18. Etude de l'effet de la date de semis et de l'Age des plantules au

    African Journals Online (AJOL)

    Les périmètres irrigués villageois (PIV) sont utilisés pour atténuer les effets néfastes des changements climatiques. Les variétés cultivées dans les PIV sont d'origine asiatique et souffrent des conditions agro climatiques des régions nord du Mali. Les expérimentations ont été conduites en milieu paysan dans les. PIV de ...

  19. Thermal, intermediate and fast neutron flux measurements using activation detectors; Mesure des flux de neutrons thermiques, intermediaires et rapides au moyen de detecteurs par activation

    Energy Technology Data Exchange (ETDEWEB)

    Brisbois, J; Lott, M; Manent, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The problem of neutron flux measurements using activation detectors is studied in the particular case of protection research. It is shown how it possible, it is possible, using a known thermal flux, to organise a coherent calibration system for all the detectors. The rapid neutron detectors are calibrated with respect to a reference detector (phosphorus) in a natural uranium converter; the intermediate neutron detectors with respect to gold in the axial channel of ZOE. This method makes it possible to minimise the errors due to the activation cross-sections. A brief description is given of the counting room of the Pile Safety Study Service, as well of the practical utilisation characteristics of the counters employed. (authors) [French] Le probleme de la mesure des flux de neutrons au moyen de detecteurs par activation est etudie dans le cas particulier des etudes de protections. On montre comment, a partir d'un flux thermique connu, on peut organiser un systeme coherent d'etalonnage de tous les detecteurs. Les detecteurs de neutrons rapides sont etalonnes par rapport a un detecteur de reference (phosphore) dans un convertisseur en uranium naturel; les detecteurs de neutrons intermediaires, par rapport a l'or dans le canal axial de ZOE, Cette methode permet de minimiser les erreurs dues aux sections efficaces d'activation. On decrit sommairement la salle de comptage du Service d'Etudes de Protections de Piles et on indique les caracteristiques d'emploi pratique des detecteurs utilises. (auteurs)

  20. Some recent results in Au+Au collisions at AGS

    International Nuclear Information System (INIS)

    Chen, Z.

    1996-01-01

    Many interesting results have been obtained for Au + Au reactions at AGS. The basic information about the reaction dynamics comes from the hadronic distribution. and this article reviews the recent progress of these distributions in details. The proton rapidity distribution shows significantly increased stopping compared to lighter systems, implying the formation of a state of high baryon density. Unlike reactions at this energy induced by lighter heavy ions, at low m t - m 0 the proton invariant spectra deviate from a single exponential shape and become fear,. while pion spectra are found to rise in this region, with the π - spectra rising faster than the π + spectra. The inverse slope parameter increases faster for particles of larger mass as the number of participants in the reaction increases, an indication of increased effect of radial expansion in central collision. Anti-proton Needs have been measured recently, and unfortunately a comparison among current results from different experiments indicates discrepancy

  1. Novel condensation of Au-centered trigonal prisms in rare-earth-metal-rich tellurides: Er7Au2Te2 and Lu7Au2Te2.

    Science.gov (United States)

    Gupta, Shalabh; Corbett, John D

    2010-07-14

    A new monoclinic structure occurs for Er(7)Au(2)Te(2) according to X-ray diffraction analysis of single crystals grown at 1200 degrees C: C2/m, Z = 4, a = 17.8310(9) A, b = 3.9819(5) A, c = 16.9089(9) A, beta = 104.361(4) degrees. The isostructural Lu(7)Au(2)Te(2) also exists according to X-ray powder pattern means, a = 17.536(4) A, b = 3.9719(4) A, c = 16.695(2) A, beta = 104.33(1) degrees. The structure contains zigzag chains of condensed, Au-centered tricapped trigonal prisms (TCTP) of Er along c that also share basal faces along b to generate puckered sheets. Further bi-face-capping Er atoms between these generate the three dimensional network along a, with tellurium in cavities outlined by augmented trigonal prismatic Er polyhedra. Bonding analysis via LMTO-DFT methods reveal very significant Er-Au bonding interactions, as quantified by their energy-weighted Hamilton overlap populations (-ICOHP), approximately 49% of the total for all interactions. These and similar Er-Te contributions sharply contrast with the small Er-Er population, only approximately 14% of the total in spite of the high proportion of Er-Er contacts. The strong polar bonding of Er to the electronegative Au and Te leaves Er relatively oxidized, with many of its 5d states falling above the Fermi level and empty. The contradiction with customary representations of structures that highlight rare-earth metal clusters is manifest. The large Er-Au Hamilton overlap population is in accord with the strong bonding between early and late transition metals first noted by Brewer in 1973. The relationship of this structure to the more distorted orthorhombic (Imm2) structure type of neighboring Dy(7)Ir(2)Te(2) is considered.

  2. Nuclear spin of 185Au and hyperfine structure of 188Au

    International Nuclear Information System (INIS)

    Ekstroem, C.; Ingelman, S.; Wannberg, G.

    1977-03-01

    The nuclear spin of 185 Au, I = 5/2, and the hyperfine separation of 188 Au, Δγ = +- 2992(30) MHz, have been measured with the atomic-beam magnetic resonance method. The spin of 185 Au indicates a deformed nuclear shape in the ground state. The small magnetic moment of 188 Au is close in value to those of the heavier I = 1 gold isotopes 190 192 194 Au, being located in a typical transition region. (Auth.)

  3. Etude de la qualité physico-chimique et biologique des eaux du ...

    African Journals Online (AJOL)

    Etude de la qualité physico-chimique et biologique des eaux du fleuve Niger à Niamey. ... le récepteur principal des rejets d'eaux usées de la ville de Niamey, capital du ... La description de ces taxons montre une variation de la structure des ...

  4. English Department Reforms at the Hautes Etudes Commerciales: Entering the Nineties.

    Science.gov (United States)

    Shanahan, Daniel

    1993-01-01

    Discusses the reforms made in the fall of 1990 in the English department at the Ecole Hautes Etudes Commerciales (Paris, France), which were based on the basis of a combination of literature-culture and second- and foreign-language acquisition pedagogical biases. (four references) (VWL)

  5. Contribution a l'etude des plantes alimentaires mineures dans la ...

    African Journals Online (AJOL)

    Contribution a l'etude des plantes alimentaires mineures dans la prefecture de Dankpen (Togo). AB Kebenzikato, S Akpavi, K Batawila, K Wala, M Dourma, K Kossi-Titrikou, KS Amouzou, I Butare, H Dantsey-Barry, K Akpagana ...

  6. 152 Etude de cas sur l'impact des amendements organiques vis-à ...

    African Journals Online (AJOL)

    john mukalay

    Etude de cas sur l'impact des amendements organiques vis-à-vis de la salinité en culture de bananier. Michel Mazinga KWEY1, Séverin Kalala BANZE2 et John Banza MUKALAY2*. 1Laboratoire des cultures in vitro, Département de phytotechnie, Faculté des sciences agronomiques,. Université de Lubumbashi, BP 1825, ...

  7. 186 Etude théorique du transport électronique par la simulation ...

    African Journals Online (AJOL)

    youness

    Choukria SAYAH et al. 186. Etude théorique du ... For that we carried out the microscopic simulations, based on the Monte. Carlo method. ... intervalles, piezoelectric as well as the interactions of alloy and on ionized impurities. ..... SAYA et al. 198. [5] - R. W. Hockney, J. W. Eastwood, "Computer simulation using particles",.

  8. Etude comparative de la flore aux abords des cours d'eau dans les ...

    African Journals Online (AJOL)

    Etude comparative de la flore aux abords des cours d'eau dans les zones hypo et hyper endémiques d'ulcère de Buruli en Côte d'Ivoire. C. Cisse Boni, E. Ehouman, D. Soro, M.W. Kone, A. Bakayoko, F. Dembele, K. Bauthire, M Dosso ...

  9. Experimental results concerning the metabolism of ingested iodine-131 in adult sheep under lactation; Resultats experimentaux relatifs au metabolisme de l'iode 131 ingere chez la brebis adulte en lactation

    Energy Technology Data Exchange (ETDEWEB)

    Daburon, F.; Capelle, A.; Tricaud, Y.; Nizza, P. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Departement de la Protection Sanitaire, Laboratoire-etable de Radiobiologie Appliquee

    1967-07-01

    The authors give the results of a series of experiments on metabolism of ingested iodine-131 in adult sheep under lactation; the measurement were carried out over a number of years from 1961 to 1966. The work was concerned initially with the fixation of iodine 131 in the thyroid gland, with the calculation of radiation doses absorbed and with ways of showing up any possible radiation damage in the gland. The modes of absorption of iodine 131 and its elimination through milk, urine and the faeces were then considered. Finally, a last chapter is devoted to changes in the radioactivity of the blood and of the milk, to variations of the PBI level of the blood serum as to different methods for measuring this level. (authors) [French] Les auteurs rapportent les resultats d'une serie d'experimentations relatives au metabolisme de l'iode 131 ingere chez la brebis adulte en lactation, et qui se sont etalees sur plusieurs annees, de 1961 a 1966. Les etudes ont porte d'abord sur les aspects de la fixation de l'iode 131 dans la thyroide, avec le calcul des doses de rayonnements absorbees et les moyens de mettre en evidence les radiolesions eventuelles de la glande. Ensuite ont ete traitees les modalites de l'absorption de l'iode 131 et de son elimination par le lait, les urines et les feces. Enfin un dernier chapitre a ete consacre a l'evolution de la radioactivite du sang et du lait, aux variations ainsi qu'aux divers moyens d'evaluation du taux de PBI du serum sanguin. (auteurs)

  10. Experimental results concerning the metabolism of ingested iodine-131 in adult sheep under lactation; Resultats experimentaux relatifs au metabolisme de l'iode 131 ingere chez la brebis adulte en lactation

    Energy Technology Data Exchange (ETDEWEB)

    Daburon, F; Capelle, A; Tricaud, Y; Nizza, P [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Departement de la Protection Sanitaire, Laboratoire-etable de Radiobiologie Appliquee

    1967-07-01

    The authors give the results of a series of experiments on metabolism of ingested iodine-131 in adult sheep under lactation; the measurement were carried out over a number of years from 1961 to 1966. The work was concerned initially with the fixation of iodine 131 in the thyroid gland, with the calculation of radiation doses absorbed and with ways of showing up any possible radiation damage in the gland. The modes of absorption of iodine 131 and its elimination through milk, urine and the faeces were then considered. Finally, a last chapter is devoted to changes in the radioactivity of the blood and of the milk, to variations of the PBI level of the blood serum as to different methods for measuring this level. (authors) [French] Les auteurs rapportent les resultats d'une serie d'experimentations relatives au metabolisme de l'iode 131 ingere chez la brebis adulte en lactation, et qui se sont etalees sur plusieurs annees, de 1961 a 1966. Les etudes ont porte d'abord sur les aspects de la fixation de l'iode 131 dans la thyroide, avec le calcul des doses de rayonnements absorbees et les moyens de mettre en evidence les radiolesions eventuelles de la glande. Ensuite ont ete traitees les modalites de l'absorption de l'iode 131 et de son elimination par le lait, les urines et les feces. Enfin un dernier chapitre a ete consacre a l'evolution de la radioactivite du sang et du lait, aux variations ainsi qu'aux divers moyens d'evaluation du taux de PBI du serum sanguin. (auteurs)

  11. Study and achievement of a digital-analog-divider; Etude et realisation d'un diviseur-analogique-numerique

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-04-01

    This apparatus is designed to give directly, in digital form, the value of the ratio Vt1/V2 two analog voltages. It consists essentially of an analog-digital coder operating by successive weighing; the comparison voltage is made proportional to the divider V2 in the coder. The input dynamics are such that the voltages Vi and V2 are all in the range -50 mV to -5 V. Each of the circuits has an input impedance of about 10 K{omega}. As for the quotient, it is a binary number given in series and parallel form; it is made up of 8 bits, this giving a change of 1/16 to 16 per jump of 1/16 in the zone where the accuracy is highest (V2 {>=} 800 mV). The time required for a division is, at best, 15 {mu}sec. During the time of calculation, the voltages V{sub 1} and V{sub 2} should not vary by more than 1 per cent and 0.5 per cent respectively. The theory of the system and the investigation of a synoptic diagram, the study of the circuits and the actual construction are presented. (author) [French] Cet appareil est destine a fournir directement sous forme numerique la valeur du rapport V1/V2 de deux tensions analogiques. Il est constitue essentiellement d'un codeur analogique-numerique fonctionnant par pesees successives dans lequel la tension de reference est rendue proportionnelle au diviseur V2. La dynamique d'entree est telle que les tensions V1 et V2 peuvent etre comprises dans l'intervalle -50 mV a -5 V. Chacune des voies presente une impedance d'entree d'environ 10 K{omega}. En ce qui concerne le quotient, c'est un nombre binaire delivre sous les formes serie et parallele ; il est compose de 8 bits, ce qui donne une variation de 1/16 a 16 par bond de 1/16 dans la zone de meilleure precision (V2 {>=} 800 mV). Le temps necessaire pour effectuer la division est au mieux de 15 {mu}s. Durant le temps de calcul les tensions V{sub 1} et V{sub 2} ne doivent pas varier respectivement de plus de 1 pour cent et 0.5 pour cent. Apres avoir etabli la theorie du systeme, les

  12. Experimental study of superconductivity induced by proximity effects; Etude experimentale de la supraconductivite induite par effets de proximite

    Energy Technology Data Exchange (ETDEWEB)

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

    1966-11-15

    We present a study of the proximity effects between a superconductor (InBi or PbBi alloys) and a 'normal' metal (Zn or Sn respectively, above their critical temperature) using essentially the tunneling techniques. On the N side, some specific properties of such an induced superconductivity are described: linear variation of the pair potential near the critical temperature of the binary layer, T{sub CNS}; reduced energy scale at T{sub CNS}; evidence of a thermodynamic critical field (called breakdown field) presented by N above its critical temperature. On the S side, we study crossing from a gapless to a quasi gapless regime. This gives a proof of a finite coherence length at T{sub CNS}. Experimental details (in particular about the preparation and measurement of tunneling junctions) are given in annexe. Possible applications are suggested. (author) [French] Nous presentons une etude experimentale des effets de proximite entre un supraconducteur (alliages d'InBi ou de PbBi) et un metal 'normal' (Zn ou Sn respectivement, pris au-dessus de leur temperature critique), en utilisant principalement des mesures d'effet tunnel. Du cote N, on met en evidence des proprietes specifiques de cette supraconductivite induite: comportement lineaire du potentiel de paires pres de la temperature critique du bilame, T{sub CNS}; echelle d'energie reduite a T{sub CNS}; apparition d'un champ critique thermodynamique (appele champ de basculement) dans N au-dessus de sa temperature critique. Du cote S, nous etudions le passage continu d'une situation 'sans bande interdite' a basse temperature et en champ fort, a une situation 'pratiquement sans bande interdite' pres de T{sub CNS} en champ nul. Ceci fournit une preuve de la non divergence de la longueur de coherence a T{sub CNS}. Les techniques experimentales (et en particulier la preparation et la mesure de jonctions tunnel) sont decrites en detail dans une annexe. On envisage des applications pratiques possibles. (auteur)

  13. Study of the aqueous chemical treatment of uranium zirconium fuels; Etude du traitement chimique des combustibles uraniumzirconium par voie seche

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, M; Nollet, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    A dry process has been studied for separating the uranium from the zirconium-either for recovering the enriched uranium from fuel element production waste, or with a view to treating this waste after irradiation. In this process the alloy is treated with hydrochloric acid at 400 deg. C in a fluidized corundum bed which causes the zirconium to volatilize as tetrachloride and the uranium to form the trichloride. This latter is then converted to the hexafluoride by attack with fluorure. After the laboratory tests, a first pilot plant with a capacity of 1 kg of alloy was tried out at the Fontenay-aux-Roses Nuclear Research Centre; this made it possible to fix the operational conditions for the process. An industrial scale plant was then built with the collaboration of the from Kuhlmann, and operated until a satisfactory process had been developed for treating the waste. This installation treats 3 kg/h of alloy with a yield for the hydrochloric acid of about 50 per cent and with a uranium loss in the zirconium tetrachloride of about 0.1 per cent. An active pilot plant capable of treating of treating a few kilos of irradiated alloy is now being studied. (authors) [French] On a etudie un procede de voie seche pour effectuer la separation de l'uranium et du zirconium - soit en vue de la recuperation de l'uranium enrichi contenu dans les dechets de fabrication des elements combustibles - soit en vue du traitement de ceux-ci apres irradiation. Ce procede consiste a attaquer l'alliage par l'acide chlorhydrique a 400 deg. C dans un lit fluidise de corindon, ce qui a pour effet de volatiliser le zirconium sous forme de tetrachlorure et de transformer l'uranium en trichlorure. Ce dernier est ensuite converti en hexafluorure par action du fluor. Apres des essais de laboratoire, un premier pilote a l'echelle de 1 kg d'alliage a ete experimente au Centre d'Etudes Nucleaires de Fontenay-aux-Roses et a permis de determiner les conditions operatoires du procede. En collaboration avec

  14. Study and achievement of a digital-analog-divider; Etude et realisation d'un diviseur-analogique-numerique

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-04-01

    This apparatus is designed to give directly, in digital form, the value of the ratio Vt1/V2 two analog voltages. It consists essentially of an analog-digital coder operating by successive weighing; the comparison voltage is made proportional to the divider V2 in the coder. The input dynamics are such that the voltages Vi and V2 are all in the range -50 mV to -5 V. Each of the circuits has an input impedance of about 10 K{omega}. As for the quotient, it is a binary number given in series and parallel form; it is made up of 8 bits, this giving a change of 1/16 to 16 per jump of 1/16 in the zone where the accuracy is highest (V2 {>=} 800 mV). The time required for a division is, at best, 15 {mu}sec. During the time of calculation, the voltages V{sub 1} and V{sub 2} should not vary by more than 1 per cent and 0.5 per cent respectively. The theory of the system and the investigation of a synoptic diagram, the study of the circuits and the actual construction are presented. (author) [French] Cet appareil est destine a fournir directement sous forme numerique la valeur du rapport V1/V2 de deux tensions analogiques. Il est constitue essentiellement d'un codeur analogique-numerique fonctionnant par pesees successives dans lequel la tension de reference est rendue proportionnelle au diviseur V2. La dynamique d'entree est telle que les tensions V1 et V2 peuvent etre comprises dans l'intervalle -50 mV a -5 V. Chacune des voies presente une impedance d'entree d'environ 10 K{omega}. En ce qui concerne le quotient, c'est un nombre binaire delivre sous les formes serie et parallele ; il est compose de 8 bits, ce qui donne une variation de 1/16 a 16 par bond de 1/16 dans la zone de meilleure precision (V2 {>=} 800 mV). Le temps necessaire pour effectuer la division est au mieux de 15 {mu}s. Durant le temps de calcul les tensions V{sub 1} et V{sub 2} ne doivent pas varier respectivement de plus de 1 pour cent et 0.5 pour cent. Apres avoir etabli la

  15. Cross section of the 197Au(n,2n196Au reaction

    Directory of Open Access Journals (Sweden)

    Kalamara A.

    2017-01-01

    Full Text Available The 197Au(n,2n196Au reaction cross section has been measured at two energies, namely at 17.1 MeV and 20.9 MeV, by means of the activation technique, relative to the 27Al(n,α24Na reference reaction cross section. Quasi-monoenergetic neutron beams were produced at the 5.5 MV Tandem T11/25 accelerator laboratory of NCSR “Demokritos”, by means of the 3H(d,n4He reaction, implementing a new Ti-tritiated target of ∼ 400 GBq activity. The induced γ-ray activity at the targets and reference foils has been measured with HPGe detectors. The cross section for the population of the second isomeric (12− state m2 of 196Au was independently determined. Auxiliary Monte Carlo simulations were performed using the MCNP code. The present results are in agreement with previous experimental data and with theoretical calculations of the measured reaction cross sections, which were carried out with the use of the EMPIRE code.

  16. Transformation of Au144(SCH2CH2Ph)60 to Au133(SPh-tBu)52 Nanomolecules: Theoretical and Experimental Study.

    Science.gov (United States)

    Nimmala, Praneeth Reddy; Theivendran, Shevanuja; Barcaro, Giovanni; Sementa, Luca; Kumara, Chanaka; Jupally, Vijay Reddy; Apra, Edoardo; Stener, Mauro; Fortunelli, Alessandro; Dass, Amala

    2015-06-04

    Ultrastable gold nanomolecule Au144(SCH2CH2Ph)60 upon etching with excess tert-butylbenzenethiol undergoes a core-size conversion and compositional change to form an entirely new core of Au133(SPh-tBu)52. This conversion was studied using high-resolution electrospray mass spectrometry which shows that the core size conversion is initiated after 22 ligand exchanges, suggesting a relatively high stability of the Au144(SCH2CH2Ph)38(SPh-tBu)22 intermediate. The Au144 → Au133 core size conversion is surprisingly different from the Au144 → Au99 core conversion reported in the case of thiophenol, -SPh. Theoretical analysis and ab initio molecular dynamics simulations show that rigid p-tBu groups play a crucial role by reducing the cluster structural freedom, and protecting the cluster from adsorption of exogenous and reactive species, thus rationalizing the kinetic factors that stabilize the Au133 core size. This 144-atom to 133-atom nanomolecule's compositional change is reflected in optical spectroscopy and electrochemistry.

  17. A Theoretical and Experimental Study of the Subtraction of Two Scintigraphic Images - As Applied to Visualization of the Pancreas; Etude Theorique et Experimentale de la Soustraction de Deux Images Scintigraphiques

    Energy Technology Data Exchange (ETDEWEB)

    Desgrez, A.; Razafindramamba, V.; Saint-Laurent, J. de; Kellershohn, C. [CEA, Service Hospitalier Frederic Joliot, Orsay (France)

    1969-05-15

    fraction of the quantity to be subtracted can be varied. The value of this latter possibility is brought out by the use of examples. (author) [French] Certaines etudes scintigraphiques sont limitees par le manque de selectivite du tissu que l'on cherche a representer vis-a-vis du produit radioactif dont on dispose. Les scintigraphies mercuriell es des tumeur s bucco-pharyngees sont ainsi genees par la radioactivite du sang circulant. Les scintigraphies pancreatiques sont de mem e genees paila fixation hepatique de la selenomethionine. De meme egalement certaines fixations hepatiques nuisent a la mise en evidence d'un rein droit en etat d'insuffisance. Une solution a ce probleme consiste a effectuer, au moyen de deux produits marques differents, deux images dont la soustraction permet d'isoler le tissu que l'on cherche a mettre en evidence. Le memoire a pour objet l' etude des differents problemes intervenant dans une telle soustraction: La coiencidence spatiale stricte des informations a soustraire n'est garantie que par l'enregistrement simultane des deux images; un enregistrement consecutif meme rapide peut etre nuisible. L'operation a effectuer est en fait souvent double: supprimer par soustraction le tissu genant, amplifier le contraste entre le tissu auquel on s'interesse et un bruit de fond persistant. Ces deux operations, soustraction et amplification, portent sur des grandeurs aleatoires; la resolution de l'image finale est en consequence sous la dependance de parametres statistiques qui sont discutes. Dans les etudes pancreatiques, les avantages respectifs ainsi que les conditions de separation spectrometrique des differents produits utilisables pour la soustraction sont envisages; l'interet du rose bengale marque, qui permet de soustraire egalement certaines anses intestinales, est souligne. Deux types d'appareillage differents permettant d'effectuer une telle soustraction sont presentes. L'un, plus economique, utilise un stockage des informations sur ruban

  18. Au nanoinjectors for electrotriggered gene delivery into the cell nucleus.

    Science.gov (United States)

    Kang, Mijeong; Kim, Bongsoo

    2015-01-01

    Intracellular delivery of exogenous materials is an essential technique required for many fundamental biological researches and medical treatments. As our understanding of cell structure and function has been improved and diverse therapeutic agents with a subcellular site of action have been continuously developed, there is a demand to enhance the performance of delivering devices. Ideal intracellular delivery devices should convey various kinds of exogenous materials without deteriorating cell viability regardless of cell type and, furthermore, precisely control the location and the timing of delivery as well as the amount of delivered materials for advanced researches.In this chapter the development of a new intracellular delivery device, a nanoinjector made of a Au (gold) nanowire (a Au nanoinjector) is described in which delivery is triggered by external application of an electric pulse. As a model study, a gene was delivered directly into the nucleus of a neuroblastoma cell, and successful delivery without cell damage was confirmed by the expression of the delivered gene. The insertion of a Au nanoinjector directly into a cell can be generally applied to any kind of cell, and a high degree of surface modification of Au allows attachment of diverse materials such as proteins, small molecules, or nanoparticles as well as genes on Au nanoinjectors. This expands their applicability, and it is expected that they will provide important information on the effects of delivered exogenous materials and consequently contribute to the development of related therapeutic or clinical technologies.

  19. The Texts of the Agency's Headquarters Agreement with Austria and Related Agreements; Textes de l'Accord Relatif au Siege Conclu Entre l'Agence et l'Autriche et d'Accords Connexes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-12-16

    The texts of the Agreement between the International Atomic Energy Agency and the Republic of Austria that were in force on 30 September 1975 are reproduced in this document for the information of all Members of the Agency [French] Les textes de l'Accord relatif au siege conclu entre l'Agence et la Republique d'Autriche et de divers accords connexes, qui etaient en vigueur le 30 septembre 1975, sont reproduits dans le present document pour l'information de tous les Membres de l'Agence.

  20. SEPA (Service d'etudes, de Procedes et Analyses)

    International Nuclear Information System (INIS)

    2017-01-01

    The SEPA (Service d'etudes, de Procedes et Analyses), is an engineering department specializing in the analysis and processing of uranium ore. It comes from a long tradition of mining in France that began sixty-five years ago with the French Atomic Energy Commission (CEA) and that has been carried on by COGEMA and then Areva. SEPA brings a combination of experience and excellence to its activities thanks to its multidisciplinary staff (mineralogists, chemists, mechanical engineers, instrumentation specialists...), who come from diverse cultural backgrounds. Today, the SEPA draws on its wealth of know-how and expertise to devise and develop new methods for processing and valorizing ores everywhere in the world. Its mission is to: - Develop and conduct laboratory tests on methods for processing uranium and other valuable elements such as molybdenum, vanadium, rare earths, niobium, tantalum and thorium; - Analyze ores obtained during prospecting at locations all over the world; -Serve as an advisor in the commissioning of Areva industrial units and ore processing plants; -Perform environmental analyses during the full period of mining operations; -Conduct audits and provide advice on processes and analysis methods; -Carry out research and development in all aspects of minerals treatment (including the filing of patents). The SEPA combines experience, skills and a global approach to technologies used in ore processing. Its role is to continually improve the processes for extracting, processing and valorizing ores while protecting the environment

  1. Evolution of Self-Assembled Au NPs by Controlling Annealing Temperature and Dwelling Time on Sapphire (0001).

    Science.gov (United States)

    Lee, Jihoon; Pandey, Puran; Sui, Mao; Li, Ming-Yu; Zhang, Quanzhen; Kunwar, Sundar

    2015-12-01

    Au nanoparticles (NPs) have been utilized in a wide range of device applications as well as catalysts for the fabrication of nanopores and nanowires, in which the performance of the associated devices and morphology of nanopores and nanowires are strongly dependent on the size, density, and configuration of the Au NPs. In this paper, the evolution of the self-assembled Au nanostructures and NPs on sapphire (0001) is systematically investigated with the variation of annealing temperature (AT) and dwelling time (DT). At the low-temperature range between 300 and 600 °C, three distinct regimes of the Au nanostructure configuration are observed, i.e., the vermiform-like Au piles, irregular Au nano-mounds, and Au islands. Subsequently, being provided with relatively high thermal energy between 700 and 900 °C, the round dome-shaped Au NPs are fabricated based on the Volmer-Weber growth model. With the increased AT, the size of the Au NPs is gradually increased due to a more favorable surface diffusion while the density is gradually decreased as a compensation. On the other hand, with the increased DT, the size and density of Au NPs decrease due to the evaporation of Au at relatively high annealing temperature at 950 °C.

  2. Italy au CERN

    CERN Multimedia

    FI Department

    2008-01-01

    4 – 6 March 2008 Main Building Bldg 60 - ground and 1st floor 09.00 hrs - 17.30 hrs Nineteen companies will present their latest technology at the "Italy at CERN" exhibition. Italian industry will exhibit products and technologies related to the field of particle physics. The main subjects are civil engineering and buildings, data processing, electrical engineering, electronics, industrial support, mechanical engineering, particle detectors and vacuum and low-temperature technology. The exhibition is being organised by the INFN of Padova. The exhibitors are listed below. More details on the firms can be found at the following link: http://fi-dep.web.cern.ch/fi-dep/structure/memberstates/exhibitions_visits.htm LIST OF EXHIBITORS Boffetti Impianti S.r.l. Bozzi & Figli S.r.l. C.A.E.N. S.p.A. Cavicel S.p.A. Comecer S.p.A. E.E.I. Elettronica Conduttori S.r.l. Euromec S.r.l. Eurotech S.p.A. IRST Fondazione Bruno Kessler IVG Colbacchini S.p.A. Krohne Italia S.r.l. Luvata For...

  3. The Au/Si eutectic bonding compatibility with KOH etching for 3D devices fabrication

    Science.gov (United States)

    Liang, Hengmao; Liu, Mifeng; Liu, Song; Xu, Dehui; Xiong, Bin

    2018-01-01

    KOH etching and Au/Si eutectic bonding are cost-efficient technologies for 3D device fabrication. Aimed at investigating the process compatibility of KOH etching and Au/Si bonding, KOH etching tests have been carried out for Au/bulk Si and Au/amorphous Si (a-Si) bonding wafers in this paper. For the Au/bulk Si bonding wafer, a serious underetch phenomenon occurring on the damage layer in KOH etching definitely results in packaging failure. In the microstructure analysis, it is found that the formation of the damage layer between the bonded layer and bulk Si is attributed to the destruction of crystal Si lattices in Au/bulk Si eutectic reaction. Considering the occurrence of underetch for Au/Si bonding must meet two requirements: the superfluous Si and the defective layer near the bonded layer, the Au/a-Si bonding by regulating the a-Si/Au thickness ratio is presented in this study. Only when the a-Si/Au thickness ratio is relatively low are there not underetch phenomena, of which the reason is the full reaction of the a-Si layer avoiding the formation of the damage layer for easy underetch. Obviously, the Au/a-Si bonding via choosing a moderate a-Si/Au thickness ratio (⩽1.5:1 is suggested) could be reliably compatible with KOH etching, which provides an available and low-cost approach for 3D device fabrication. More importantly, the theory of the damage layer proposed in this study can be naturally applied to relevant analyses on the eutectic reaction of other metals and single crystal materials.

  4. La migration féminine au Mali

    OpenAIRE

    KEITA, Modibo

    2011-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) Les données et les recherches au sujet de la migration féminine au Mali sont rares. Cet article, qui privilégie une approche qualitative, suggère d’approfondir la question de la relation entre migration féminine et promotion de la femme, autrement dit la connaissance des conséquences de la migration féminine aux plans individuel, social, économique et culturel. Cette question renvoie, plus largement, à la...

  5. L’apprentissage au CERN

    CERN Multimedia

    Staff Association

    2016-01-01

    En 1961, sur la base du constat que l’évolution du marché du travail nécessitait un besoin croissant de personnel qualifié, le 1er accord entre la République et canton de Genève et le CERN fut signé. Cet accord avait notamment pour objet la formation professionnelle de jeunes électroniciens et techniciens de laboratoires en physique. Le CERN, acteur local économique d’importance, soulignait par cet accord sa volonté de participer au développement économique et social local. Le 1er apprenti arriva au CERN en 1965. En 1971, le centre d’apprentissage fut créé ; il accueille aujourd’hui plus d’une vingtaine d’apprentis au total, à raison d’environ six nouveaux apprentis chaque année. Cet apprentissage est dédié aux jeunes âgés e...

  6. Formation of Ag2, Au2 and AgAu particles on MgO(1 0 0): DFT study on the role of support-induced charge transfer in metal-metal interactions

    International Nuclear Information System (INIS)

    Fuente, Silvia A.; Belelli, Patricia G.; Branda, Maria M.; Ferullo, Ricardo M.; Castellani, Norberto J.

    2009-01-01

    The formation of Ag 2 , Au 2 and AgAu particles oriented perpendicularly to the MgO(1 0 0) surface was studied using the density functional theory. While the support induces a slight enhancement of the Ag-Ag bond (by 0.3-0.4 eV), the Au-Au bond is strongly enhanced (by 0.8-1.1 eV). Concerning the bimetallic particle, the Ag-Au bond stabilization depends on the relative position of each atom. Thus, in general terms, the strength of the metal-metal bond is determined by the nature of the terminal atom; the bond is stronger in Au-terminal particles. The partial electronic charge transfer to the terminal Au atom and its ability to polarize this charge are responsible for this energetic stabilization.

  7. How Does Amino Acid Ligand Modulate Au Core Structure and Characteristics in Peptide Coated Au Nanocluster?

    Science.gov (United States)

    Li, Nan; Li, Xu; Zhao, Hongkang; Zhao, Lina

    2018-03-01

    The atomic structures and the corresponding physicochemical properties of peptide coated Au nanoclusters determine their distinctive biological targeting applications. To learn the modulation of amino acid ligand on the atomic structure and electronic characteristics of coated Au core is the fundamental knowledge for peptide coated Au nanocluster design and construction. Based on our recent coated Au nanocluster configuration study (Nanoscale, 2016, 8, 11454), we built the typically simplified Au13(Cys-Au-Cys) system to more clearly learn the basic modulation information of amino acid ligand on Au core by the density functional theory (DFT) calculations. There are two isomers as ligand adjacent bonding (Iso1) and diagonal bonding (Iso2) to Au13 cores. The geometry optimizations indicate the adjacent bonding Iso1 is more stable than Iso2. More important, the Au13 core of Iso1 distorts much more significantly than that of Iso2 by Cys-Au-Cys bonding through the root-mean-square deviation (RMSD) analysis, which modulate their electronic characteristics in different ways. In addition, the frontier molecular orbital results of Au13(Cys-Au-Cys) isomers confirm that the Au cores mainly determine the blue shifts of Au13(Cys-Au-Cys) systems versus the original Au13 core in their UV-visible absorption spectrum studies. The configuration of Au13 core performs deformation under Cys-Au-Cys ligand modulation to reach new stability with distinct atomic structure and electronic properties, which could be the theory basis for peptide coated AuNCs design and construction.

  8. Contribution to the study of neutron propagation in cavities; Contribution a l'etude de la propagation des neutrons dans les cavites

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-07-01

    In large size cavities where the dimensions of the holes are greater than the mean free path of the radiations, the neutron propagation calculations are carried out by taking into account the effect of the medium surrounding the hole using a reflection coefficient or albedo. In this work the fast neutron albedos are obtained for various materials and these results are applied for a Monte-Carlo propagation calculation. A comparison of this calculation with experimental results shows the validity of the method. (author) [French] Dans les cavites de grandes dimensions, ou les dimensions des vides sont superieures au libre parcours moyen des rayonnements, le calcul de la propagation des neutrons se fait en essayant de rendre compte de l'effet du milieu entourant le vide, par un coefficient de reflexion ou albedo. Dans cette etude, sont d'une part obtenus des albedo en neutrons rapides sur divers materiaux, d'autre part ces resultats sont appliques pour un calcul de MONTE-CARLO de propagation. La comparaison entre le calcul et l'experience montre la validite de la methode. (auteur)

  9. Contribution to the study of neutron propagation in cavities; Contribution a l'etude de la propagation des neutrons dans les cavites

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-07-01

    In large size cavities where the dimensions of the holes are greater than the mean free path of the radiations, the neutron propagation calculations are carried out by taking into account the effect of the medium su