Évaluation du niveau de pollution par les métaux lourds des lacs ...

African Journals Online (AJOL)

La présente étude a pour objectif principal d'évaluer le niveau de pollution métallique des lacs Bini et Dang (Ngaoundéré, Cameroun) à travers l'analyse des eaux et des sédiments de surface. La concentration des métaux lourds (Ni, Cr, Fe, Pb, Cd, Zn) a été mesurée par spectrophotométrie d'absorption atomique.

Rewriting Classical Myths: Women's Voices in “Los motivos de Circe” and “Penélope” by Lourdes Ortiz

Directory of Open Access Journals (Sweden)

Morgado, Nuria

2013-06-01

Full Text Available The purpose of this article is to explore the mythical representations in two of the six short stories that make up Lourdes Ortiz's Voces de mujer (2007, previously published under the title Los motivos de Circe. It is well known that most rewritings of the classical myths have been faithful to the “official truth” of the original versions. But recent works in search of other meanings, have explored dimensions often hidden or blurred by the “official” version. This is the case of the short stories in this collection whose protagonists are six archetypal or mythical women and their respectful references to the biblical, Homeric and pictorial world: Eve, Circe, Penelope, Betsabé, Salomé and Gioconda. The perspective offered by Lourdes Ortiz about the history of these myths allows us to read the story from the point of view of her female heroines. As such, then, in this article I will focus on two female characters from the Homeric epic: Circe and Penelope.El propósito de este artículo es explorar las representaciones míticas en dos de los seis cuentos que componen Voces de mujer (2007, de Lourdes Ortiz, publicado anteriormente bajo el título Los Motivos de Circe. Es bien sabido que la mayoría de las reescrituras de los mitos clásicos han sido fieles a la “verdad oficial” de las versiones originales. Sin embargo, trabajos recientes han explorado las dimensiones a menudo silenciadas por la versión “oficial”. Este es el caso de los cuentos de esta colección cuyas protagonistas son seis mujeres arquetípicas o míticas, y sus referencias con el mundo bíblico, homérico y pictórico: Eva, Circe, Penélope, Betsabé, Salomé y Gioconda. La perspectiva ofrecida por Lourdes Ortiz sobre estos mitos nos permite leer la historia desde el punto de vista de sus heroínas femeninas. Este artículo se centra en dos personajes femeninos de la épica de Homero: Circe y Penélope.

Influence de la nature des fuels lourds sur la qualité de leur combustion Influence of Heavy Fuel Oil Composition on Particulate Emissions

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Feugier A.

2006-11-01

Full Text Available A partir d'études de combustion de fuels lourds numéro 2 effectuées dans une chaudière de 1 MW et dans un foyer de 0,1 MW, on conclut que le résidu de Carbone Conradson (CCR des fuels est un bon indicateur de leur combustibilité, mais qu'il n'est pas suffisant dans tous les cas, c'est-à-dire que pour un même CCR, on peut mesurer des valeurs différentes en indice pondéral. Plusieurs interpréta. tions possibles ont été proposées et vérifiées : a Le résidu de Carbone Conradson, résultat d'une pyrolyse lente, est une procédure qui n'est pas suffisamment représentative des conditions réelles. Or, en soumettant un certain nombre de fuels à une pyrolyse flash (technique de la grille chauffée, on observe une bonne corrélation entre la quantité de résidu résultant et le CCR. Donc, ce dernier reste un bon indicateur de combustibilité. b Pour les fuels ex résidu atmosphérique, ex résidu sous-vide et ex désasphaltage, on détermine de satisfaisantes corrélations entre le CCR et certaines caractéristiques physico-chimiques de la fraction lourde des fuels (point de coupe choisi 450°C : polyaromaticité (mesurée par RMN du Carbone 13, C/H, masse moléculaire. Cependant, les fuels de visco-réduction satisfont à d'autres corrélations, de même que les résidus de vapocraquage. Donc, pour ces classes de fuels, on peut prévoir des anomalies entre indice pondéral et CCR, ce qui est observé dans certains équipements. c On observe que pour une même valeur de CCR, la proportion relative entre fractions légères et fractions lourdes des fuels peut parfois varier très sensiblement avec pour conséquence des modifications dans les cartes de richesse et de température des flammes résultantes, et donc des variations dans les émissions particulaires. L'importance de telles variations dépendra des types de brûleurs et de chambres de combustion dans lesquelles la flamme se développera. On the basis of combustion runs of

État des connaissances sur le traitement thermique des produits lourds State of the Art of the Thermal Treatment of Heavy Products

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Blouri B.

2006-11-01

Full Text Available Après rappel du traitement thermique des hydrocarbures comme un moyen de viscoréduction des charges lourdes, craquage en oléfines gazeuses, ou pyrolyse totale en gaz de synthèse, le mécanisme réactionnel de vapocraquage des produits lourds constitue la première partie de l'article. Le craquage des huiles lourdes s'effectue selon un mécanisme radicalaire, tandis que les dépôts de carbone sont formés par des réactions de cycloadditions et polycondensations à des températures moyennes et par l'intermédiaire des radicaux à haute température. L'étude expérimentale du craquage thermique du n-tétracosane, du méthyl-6 eicosane et du dodécylbenzène constitue la deuxième partie de l'article et elle met en évidence, grâce à un mécanisme réactionnel du type moléculaire, la possibilité de craquage contrôlé d'une isoparaffine ou d'un hydrocarbure aromatique lourd en hydrocarbure liquide plus léger. After reviewing the thermal treatment of hydrocarbons as a way of visbreaking heavy feedstock, cracking them into gaseous olefins, or totally pyrolyzing them into synthetic gas, the first part of this article describes the reac-tion mechanism of the steam cracking of heavy products. Heavy oils are cracked by a radical mechanism, while carbon deposits are formed by cycloaddition and polycondensation reactions at mean temperatures and by the intermediary of radicals at high temperature. An experimental investigation of the thermal cracking of n-tetracosane, 6-methyleicosane and dodecylbenzene makes up the second part of the article. A reaction mechanism of the molecular type is used to describe the possibility of the controlled cracking of an isoparaffin or of a heavy aromatic hydrocarbon into a lighter liquid hydrocarbon.

Mesure asymétrie avant-arriere des quarks lourds a LEP1 avec le détecteur OPAL

CERN Document Server

Lafoux, H

A partir de l'ensemble des données accumulées par OPAL au cours de la première phase de fonctionnement du LEP, nous avons mesuré l'asymétrie avant-arrière des quarks b et c au voisinage du pic du Zo. Utilisant une méthode traditionnelle, basée sur la détection des leptons produits dans les désintégrations semi-leptoniques des hadrons lourds, nous avons cherché à optimiser chaque étape de la mesure, en mettant en œuvre les algorithmes les plus appropriés. Le recours aux réseaux de neurones artificiels s'est en particulier avéré d'une grande utilité lorsque le problème à résoudre impliquait la prise en compte simultanée de multiples sources d'informations, d'origine et de nature très variées. Nos résultats sont en bon accord avec ceux des autres mesures effectuées à LEP et compatibles avec les prédictions du Modèle Standard pour un quark top de 174 ± 31 GeV/c2 et un boson de Higgs de masse comprise entre 60 et 1000 GeV/c2

The search for super-heavy ions; La quete des noyaux super-lourds

Energy Technology Data Exchange (ETDEWEB)

Grevy, St. [Grand Accelerateur National d' Ions Lourds (GANIL-LPC), IN2P3 - CNRS / Ensicaen et Universite, 14 - Caen (France); Stodel, Ch. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA-CNRS-IN2P3, 14 - Caen (France)

2003-07-01

The authors present the search for heavy nuclei, they briefly draw a historical review of the production of heavy isotopes and then describe the means and possibilities the French GANIL (national great accelerator of heavy ions) facility offers. The different steps of the experimental process are described: production, selection, detection and identification. The production cross-sections are so weak that every parameter involved in the production process has to be optimized. It appears that the limit of our technological knowledge has been reached and unless an important technical step forward it seems impossible to go down below the pico-barn (10{sup -12}*10{sup -24} cm{sup 2}) for production cross-sections. The 2 remaining ways to improve the situation are: 1) to increase the intensity of the incident particle beam (today we have < 10{sup 13} pps), this implies that an important development about accelerators and ion sources has to be achieved, 2) the other way is to use radioactive ion beams, the excess of neutrons of the incident ion gives a better production rate and will allow us to reach the neutron-rich part of the stability island. (A.C.)

Magnetic concentration of iron-titanium ore with vanadium concentrate from campo Alegre de Lourdes - Bahia, Brazil

International Nuclear Information System (INIS)

Delgado, O.; Silva, F.T. da; Ogasawara, T.; Soares, G.F.

1988-01-01

The feasibility studies of magnetic concentration of the Campo Alegre de Lourdes ore were carried out, trying to obtain a maximum recovery of vanadium. As a consequence of the complex nature of the ore, mainly due to the presence of ilmenite as a exolutions in the interior of hematite/martite particles, it was not possible to separate the hematite-ilmenite eficiently, wich would be necessary for obtaining a high grade vanadium concentrate with low titanium content. (author) [pt

Evaluation of exploitation alternatives of iron - titanium - vanadium ore from Campo Alegre de Lourdes (Bahia-Brazil)

International Nuclear Information System (INIS)

Cassa, J.C.S.; Ogasawara, T.; Silva, F.T. da; Cuellar, O.D.

1987-01-01

An evaluation of experiences carried out in order to develop an economic process for vanadium, is presented. The attempts which are being developed in the Metallurgical Engineering Program at COPPE/UFRJ, are described, and the other technical and economical possibilities of existing technologies, are analysed. The advantages and disadvantages of integrated steel making process to recover iron, titanium and vanadium contained in the ore from Campo Alegre de Lourdes deposit, in Bahia-Brazil are considered. (Author) [pt

Contribution de la pyrolyse des produits lourds à la valorisation des pétroles bruts Contribution of the Pyrolysis of Heavy Products to the Upgrading of Crude Oils

Directory of Open Access Journals (Sweden)

Charlot J. C.

2006-11-01

Full Text Available Le raffineur achète des pétroles bruts, de différentes qualités et d'origines variées, et il fabrique un certain nombre de produits répondant à des spécifications de qualité pour les vendre dans des proportions correspondant aux besoins du marché. Il est nécessaire pour cela d'assurer l'équilibre général entre l'approvisionnement en brut et la demande du marché en produits finis. Les facteurs traduisant l'évolution des pétroles bruts (souci de diversification géographique et politique, désir des producteurs de traiter les bruts faciles et d'exporter les lourds, compétitivité de plus en plus grande des bruts non-conventionnels, grande disponibilité d'huiles lourdes montrent l'alourdissement progressif des approvisionnements. L'enchérissement des produits pétroliers provoque de plus en plus un allègement des besoins du marché (légère augmentation des carburants, baisse des distillats moyens, chute importante des fuels lourds. Du fait de l'alourdissement des bruts conventionnels, de la grande disponibilité des huiles lourdes et de l'allègement considérable du marché des produits finis, il devient nécessaire d'utiliser des charges de plus en plus lourdes dans les procédés de conversion. La production d'oléfines peut s'effectuer à partir d'une gamme très large de coupes pétrolières, mais lorsqu'on cherche à alourdir la charge des unités de pyrolyse, il faut se poser les questions suivantes : - quelle est la souplesse des unités existantes et à venir par rapport à la charge ? - quelle est la limite industrielle et l'alourdissement de la charge ? - quel est le rôle des impuretés sur le fonctionnement des unités ? - quels sont les problèmes technologiques posés par le traitement de ces charges ? - qu'en est-il de l'amélioration des bilans énergétiques et économiques lorsque la charge s'alourdit ? A refiner buys crude oils of different qualities and varying origins and he manufactures a certain number

2. Familles et baisse de la fécondité en Afrique sub-saharienne : entre contraintes et innovations

OpenAIRE

Locoh, Thérèse

2016-01-01

L’Afrique défraie régulièrement l’actualité, mais c’est essentiellement pour les catastrophes qui s’abattent sur elle que l’opinion internationale en entend parler Le sida, au-delà des drames individuels, compromet les progrès effectués en matière de mortalité et fait régresser l’espérance de vie des pays les plus touchés. La croissance très rapide de la population (environ 3 % par an entre 1960 et 1980) a imposé de lourdes charges aux États (charges qui n’ont été que rarement assumées). Dans...

Norovirus disease associated with excess mortality and use of statins : A retrospective cohort study of an outbreak following a pilgrimage to Lourdes

NARCIS (Netherlands)

Rondy, M.; Koopmans, M.; Rotsaert, C.; van Loon, T.; Beljaars, B.; van Dijk, G.; Siebenga, J.; Svraka, S.; Rossen, J. W. A.; Teunis, P.; van Pelt, W.; Verhoef, L.

Although norovirus infection is generally known to be a mild disease, there is some evidence for severe outcome. An outbreak in a Dutch psychiatric institution, originating from pilgrims returning from Lourdes (France), provided an opportunity for performing a retrospective cohort study in order to

Présence de métaux lourds et de résidus médicamenteux dans les ...

African Journals Online (AJOL)

Les médicaments identifiés dans les effluents sont essentiellement des analgésiques et des psychotropes. La concentration en métaux lourds des effluents des trois hôpitaux est inférieure aux normes sénégalaises et de celles de L'OMS fixant les conditions de rejet de métaux dans les eaux usées. Cependant, bien que les ...

Contribution à l'évaluation de la pollution marine par le métaux lourds (Cd, Cu, Fe, Pb, Zn) chez la coralline (Corallina officinalis) de la baie de Ghazaouet (W. de Tlemcen)

OpenAIRE

DOUAHI, Somia

2015-01-01

Ce travail consiste à démontrer la présence des métaux lourds chez la coralline et cela dans le cadre d'une contribution a une étude de la bioaccumulation des éléments métallique dans le littoral de Ghazaouet. Cette étude quantitative permet d'une part de consolider les résultats des études antérieurs en démontrant la présence des métaux lourds dans le littoral, et d'autre part, de démontrer l'évolution quantitative de cinq polluants, notamment, le Cadmium, le cuivre, le fer...

Heavy water reactors physics; Physique des reacteurs a eau lourde

Energy Technology Data Exchange (ETDEWEB)

Girard, Y; Lourme, P; Naudet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

An important research programme on heavy water reactor physics has been carried out in France for quite a few years. The decision to build the EL 4 prototype and so to choose the heavy water gas cooled type has renewed the interest in this programme and at the same time given to it a more specific orientation A summary of the results gained in this field is presented in this paper. In the first part are described the experimental investigations, most of them were carried out in the criticality facility AQUILON II. The experiments are grouped in four parts - Systematic studies of lattices Buckling measurements. - Specific studies of gas-cooled lattices. - Fine structure, spectral indices measurements etc... - Measurements on lattices or samples containing Uranium of various enrichment or Plutonium. The second part is devoted to a summary of the theoretical studies. The whole results have allowed an improvement of the calculation methods, have led to a better understanding of the neutron balance in lattices, and have permitted the establishment of a set of formula to predict not only the clean fuel conditions but also the evolution of the nuclear properties with irradiation. Some specific studies on power reactor are quoted. (authors) [French] Un important programme d'etudes sur la physique des reacteurs a eau lourde est mene en France depuis assez longtemps. La decision de construire le prototype EL 4 et de s'engager ainsi dans la filiere des reacteurs a eau lourde refroidis par gaz a redonne un nouvel interet a ce programme et l'a en meme temps oriente dans une direction plus particuliere. La presente communication, rassemble les resultats des etudes faites dans ce domaine depuis la derniere conference de Geneve. Dans la premiere partie on decrit les etudes experimentales dont la plupart ont ete effectuees dans la pile d'experiences critiques Aquilon II. Les experiences sont groupees en quatre ensembles: etude systematique de reseaux (mesures de laplaciens) etudes

Relation between the swelling and the disordering in ionic crystals irradiated by fast heavy ions; Relation entre le gonflement et la creation de defauts dans les cristaux ioniques irradies par des ions lourds rapides

Energy Technology Data Exchange (ETDEWEB)

Boccanfuso, M

2001-12-01

When fast heavy ions penetrate in matter, they slow down essentially by depositing their energy on the electrons. This can lead to strong electronic excitation densities in the solid and then to structural modifications. In this work, calcium fluoride (CaF{sub 2}) was used to look further into the damage induced by irradiation with fast heavy ions in ionic crystals. Four techniques were mainly employed to characterise this damage. These techniques of analysis are wide angle X-ray diffraction, surface profilometry, Rutherford backscattering spectrometry and UV-visible optical absorption spectroscopy. The results of this work show that CaF{sub 2} answers in a multiple way to the electronic excitations. For stopping powers higher than approximately 5 keV/nm, a polygonization seems to occur. This causes a structural disorder, a swelling of 0.27 % and the formation of fractures in the material. A second damage mechanism is caused above approximately 13 keV/nm and results in a loss of the initial crystalline structure. However, optical centres appear whatever the ion stopping power, which indicates that these defects cannot be the cause of the two above mentioned damage mechanisms. According to a thermal spike model, the two thresholds can be linked to melting and sublimation energy of the material, respectively. (author)

A new temperature effect in ionized media in the presence of heavy negative electrical charges; Sur un nouvel effet de temperature dans des milieux ionises en presence de charges electriques negatives lourdes

Energy Technology Data Exchange (ETDEWEB)

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

1967-12-01

A relatively large electromotive force appears between two electrodes having different temperatures in an atmosphere of ionized vapours. The theoretical interpretation of this phenomenon is based essentially on the one hand on the massive formation of heavy negative electrical charges near the 'cold' electrode and on the other hand, in the case of flames, on the existence of an electronic temperature much higher than that predicted by conventional theory. This temperature effect makes it possible to convert the ionizing energy directly into electricity. (author) [French] Une force electro-motrice relativement importante apparait dans des vapeurs ionisees entre deux electrodes maintenues a des temperatures differentes. L'interpretation theorique, de ce phenomene est essentiellement basee, d'une part sur la formation massive de charges electriques negatives lourdes pres de l'electrode ''froide'' et, d'autre part, dans le cas des flammes sur l'existence d'une temperature electronique beaucoup plus elevee que celle prevue par la theorie classique. Cet effet de temperature permet de convertir directement l'energie ionisante en electricite. (auteur)

Natural uranium lattice in heavy water; Reseaux uranium naturel-eau lourde

Energy Technology Data Exchange (ETDEWEB)

Girard, Y; Koechlin, J C; Moreau, J; Naudet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-07-01

all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [French] Un ensemble de mesures de Laplaciens a ete realise en regime critique dans une pile a eau lourde construite specialement a cette fin, soit sur reseaux complets, soit sur echantillons de reseaux par une methode a deux zones. L'appareillage experimental est brievement decrit: il a ete etudie pour permettre des modifications rapides du chargement. On decrit egalement sommairement les methodes de mesure: on opere soit par cartes de flux, sur des reseaux qui servent ensuite de reference soit par remplacement progressif des barres par couronnes concentriques et mesures de reactivite. Dans ce cas, on cherche a atteindre l'ecart entre le laplacien-matiere du reseau central inconnu et celui du reseau de reference. La methode a fait l'objet d'une mise au point destinee a la rendre precice. On donne les resultats des mesures de laplaciens pour tous ces types de reseaux, ce qui permet de construire un ensemble de courbes en fonction du pas. Divers effets ont ete egalement mesure: equivalent en reactivite du millimetre d'eau - anisotropie - effet de temperature, etc. On a cependant prefere, dans cette premiere campagne de mesures tout au moins, obtenir une grande variete de laplaciens plutot que des mesures fines dans des cas particuliers. C'est dans cet esprit qu'a ete conduite l'interpretation des resultats. Nombre de phenomenes tres complexes echappant encore a nos possibilites de calcul, on estime qu'un certain nombre d

Natural uranium lattice in heavy water; Reseaux uranium naturel-eau lourde

Energy Technology Data Exchange (ETDEWEB)

Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-07-01

all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [French] Un ensemble de mesures de Laplaciens a ete realise en regime critique dans une pile a eau lourde construite specialement a cette fin, soit sur reseaux complets, soit sur echantillons de reseaux par une methode a deux zones. L'appareillage experimental est brievement decrit: il a ete etudie pour permettre des modifications rapides du chargement. On decrit egalement sommairement les methodes de mesure: on opere soit par cartes de flux, sur des reseaux qui servent ensuite de reference soit par remplacement progressif des barres par couronnes concentriques et mesures de reactivite. Dans ce cas, on cherche a atteindre l'ecart entre le laplacien-matiere du reseau central inconnu et celui du reseau de reference. La methode a fait l'objet d'une mise au point destinee a la rendre precice. On donne les resultats des mesures de laplaciens pour tous ces types de reseaux, ce qui permet de construire un ensemble de courbes en fonction du pas. Divers effets ont ete egalement mesure: equivalent en reactivite du millimetre d'eau - anisotropie - effet de temperature, etc. On a cependant prefere, dans cette premiere campagne de mesures tout au moins, obtenir une grande variete de laplaciens plutot que des mesures fines dans des cas particuliers. C'est dans cet esprit qu'a ete conduite l'interpretation des resultats. Nombre de phenomenes tres complexes echappant encore a nos possibilites de

Fast neutron flux in heavy water reactors; Flux de neutrons rapides dans les piles a eau lourde

Energy Technology Data Exchange (ETDEWEB)

Brisbois, J; Katz, S [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France)

1966-07-01

The possibility of calculating the fast neutron flux in a natural uranium-heavy water lattice by superposition of the individual contributions of the different fuel elements was verified using a one-dimension Monte-Carlo code. The results obtained are in good agreement with experimental measurements done in the core and reflector of the reactor AQUILON. (author) [French] La possibilite de calculer le flux de neutrons rapides dans un reseau d'uranium naturel a eau lourde par superposition des apports des divers barreaux, a ete verifiee en utilisant un code Monte-Carlo monodimensionel. Les resultats obtenus concordent avec des mesures experimentales effectuees dans le coeur et reacteur de la pile Aquilon. (auteurs)

Radioactive ion beam production by the ISOL method for SPIRAL

International Nuclear Information System (INIS)

Landre-Pellemoine, Frederique

2001-01-01

This work is directly related to the SPIRAL project (Systeme de Production d'Ions Radioactifs Acceleres en Lignes) of which the start up will begin in September 2001 at GANIL (Grand Accelerateur National d'Ions Lourds) in Caen. This thesis primarily concerns the development of radioactive ion production systems (target/ion source) by the thorough study of each production stage of the ISOL (Isotopic Separation On Line) method: target and/or projectile fragmentation production, diffusion out of target material, effusion into the ion source and finally the ionization of the radioactive atoms. A bibliographical research and thermal simulations allowed us to optimize materials and the shape of the production and diffusion targets. A first target was optimized and made reliable for the radioactive noble gases production (argon, neon...). A second target dedicated to the radioactive helium production was entirely designed and realised (from the specifications to the 'off line' and 'on line' tests). Finally, a third target source system was defined for singly-charged radioactive alkaline production. The intensities of secondary beams planned for SPIRAL are presented here. A detailed study of the diffusion effusion efficiency for these various targets showed that the use of a fine microstructure carbon (grain size of 1 μm) improved the diffusion and showed the importance of thickness of the lamella for the short lived isotope effusion. (author) [fr

Problems raised by radioactive ion acceleration in the SPIRAL project. Accelerator tuning and stabilisation; Problemes poses par l`acceleration d`ions radioactifs dans le project SPIRAL. Reglage et stabilisation de l`accelerateur

Energy Technology Data Exchange (ETDEWEB)

Boy, L. [Paris-6 Univ., 75 (France)

1997-12-31

This study is related to the SPIRAL project. This facility uses a cyclotron to accelerate radioactive ion beams produced in a thick target by the Grant Accelerateur National d`Ions Lourds primary beam. The low intensity of radioactive beams and the mixing of several species imply special tuning methods and associated diagnostics. Also, a cyclotron and the beam line will be used to switch from this tuning beam to the radioactive one. We present a theoretical study and a numerical simulation of the tuning of five radioactive beams using three different methods. the beam dynamic is performed through the injection beam line and the cyclotron up to the electrostatic deflector. Within the frame of these methods we have described all the SPIRAL beam diagnostics. Construction and test of a new low intensity diagnosis based on a plastic scintillator for phase measurement inside the cyclotron is described in details. (author). 63 refs.

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)

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)

Développements récents dans le domaine de l'hydrotraitement des fractions lourdes Advances in the Hydrotreatment of Heavy Petroleum Feedstocks

Directory of Open Access Journals (Sweden)

Jacquin Y.

2006-11-01

Full Text Available L'évolution du raffinage vers une utilisation des produits pétroliers pour les usages des transports et comme base pour la pétrochimie renforce l'intérêt pour les procédés de transformation des fractions lourdes du pétrole en fractions légères correspondant au marché actuel. Les problèmes posés par le raffinage des résidus de distillation sont semblables à ceux rencontrés pour le traitement des bruts lourds non conventionnels. Les méthodes qui sont actuellement envisagées peuvent être classées en 2 catégories : les méthodes de raffinage avec rejet de carbone comme la cokéfaction et le désasphaltage et les méthodes sans rejet de carbone comme la viscoréduction, l'hydroviscoréduction et l'hydrotraitement catalytique. Chacune de ces techniques est examinée en précisant les rendements en produits liquides qu'elle permet d'atteindre et les hydrotraitements complémentaires nécessaires pour obtenir des produits répondant aux spécifications du marché des produits pétroliers. Les progrès réalisés dans la conception des catalyseurs utilisés pour le traitement des produits lourds permet aujourd'hui d'envisager l'hydrotraitement direct des résidus sous vide de la majorité des bruts raffinés. The increasing use of refined petroleum products for transportation purposes and as petrochemical bases reinforces interest in processes for converting heavy fractions into light fractions suitable for today's market. The refining of distillation residues involves difficulties similar to unconventional heavy-crude processing. As of now methods may be classified in two categories: (i refining methods with carbon rejection such as coking and deasphalting processes, and (ii methods without carbon rejection such as visbreaking, hydrovisbreaking and catalytic hydrotreating. Each of these techniques is examined, taking into account the liquid-product yields it may reach, and the additional hydrotreatments necessary to meet market

Measurement of the purity of graphite and heavy water; Controle de purete du graphite et de l'eau lourde

Energy Technology Data Exchange (ETDEWEB)

Hering, H

1959-02-01

The analytical methods used by the C.E.A. are described, I -- Graphite. The determination of the change in the neutron capture cross section from sample to sample is determined by, an oscillation method in the Zoe reactor, or by measuring the attenuation of a neutron flux in the subcritical system Mireille. Methods of analysing total ash, B, H, Cl, Na, Ca. Fe, Mo, Ti, V, Sm, Eu, Dy, S, Co and Cd are described and mean results are given. The methods for sampling are indicated. II -- Heavy crater. The isotopic analysis of heavy water is carried out by infra-red absorption measurements. Chemical purity is evaluated by electrical conductivity measurements, B, Na, Mg, K, Cr, Mn, Ni, Cu, Cd, are determined by spectrographic methods, and Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup --}, NH{sub 4}{sup +} by chemical methods; finally, sensitive pH measurements are described. [French] On decrit les methodes d'examen en usage au Commissariat a l'Energie Atomique. I -- Graphite. L'evaluation de la capture neutronique se fait par oscillation dans la pile Zoe, ou par mesure de l'attenuation d'un flux neutronique dans l'empilement sous critique Mireille. On indique les methodes de dosages et des resultats de: cendres, B, H, Cl, Na, Ca, Fe, Mo, Ti, V, Sm, Eu, Dy, et de S, Co, Cd, ainsi que les modalites d'echantillonnage. II.- Eau lourde. Le dosage isotopique dans les eaux lourdes se fait par absorptiometrie infrarouge. Leur purete chimique est evaluee par mesure de leur conductibilite electrique; les dosages d'impuretes se font par spectrographie d'emission (B, Na, Mg, K, Mn, Ni, Cu, Cd) et par des methodes chimiques (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup --}, NH{sub 4}{sup +}). On decrit la delicate mesure de pH. (auteur)

Inelastic collisions of heavy ions and their reaction mechanisms; Collisions inelastiques d'ions lourds et mecanismes de reaction

Energy Technology Data Exchange (ETDEWEB)

Scarpaci, J.A

2004-06-01

This work is dedicated to the study of inelastic collisions of heavy ions. Most experiments took place in Ganil facility. The 2 first chapters introduce the notion of inelastic scattering of heavy ions. The third chapter deals with target excitation, giant monopolar or dipolar or quadrupolar resonances ant the multi-phonon concept and presents relevant experimental results from the Ca{sup 40} + Ca{sup 40} nuclear reaction at 50 MeV/A. The fourth chapter is dedicated to nuclear processes involved in inelastic collisions: pick-up break-up mechanisms, the angular distribution of emitted protons and the towing mode. These notions are applied to the reaction Zr{sup 90}(Ar{sup 40}, Ar{sup 40}'). The fifth chapter presents the solving of the time dependent Schroedinger equation (TDSE) applied to the wave function of a particle plunged in a variable potential. TDSE solving is applied to the break-up of Be{sup 11}. These calculations have been validated by comparing them with experimental results from the nuclear reaction Ti{sup 48}(Be{sup 11}, Be{sup 10} + n + {gamma}) that is described in the chapter 6. The last chapter presents the advantages of inelastic scattering considered as a tool to study exotic nuclei.

Extraction of vanadium from campo Alegre de Lourdes (BA, Brazil) Fe-Ti-V ore by partial reduction/magnetic concentration/salt roasting/hot water leaching

International Nuclear Information System (INIS)

Alcantara, E.M.; Ogasawara, T.; Silva, F.T. da; Fontes, E.F.

1988-01-01

A process under development at COPPE/UFRJ to rocover vanadium from a titaniferous magnetite type ore from Campo Alegre de Lourdes (Bahia, Brazil), throxgh magnetizing roasting/magnetic concentration/ salt roasting/hot water leaching, is described. The results of the experimental work carried cut up to present are in qualitative agrement with those of othar studies on salt roasting/water leaching of titaniferous magnetites. Is is discussed the existing relationship between the maximum percentags of vanadium extraction in the leaching and the salt roasting conditions. (author) [pt

“Present Your Bodies”: Film Style and Unknowability in Jessica Hausner’s Lourdes and Dietrich Brüggemann’s Stations of the Cross

Directory of Open Access Journals (Sweden)

Catherine Wheatley

2016-05-01

Full Text Available Since 2005, a number of European films have emerged examining the legacy of Christianity in Western Europe, and the ways in which men, women and children struggle to negotiate questions of religion and secularity, the personal and the institutional, faith and doubt. This article looks at two of these films—Jessica Hausner’s Lourdes (2009 and Dietrich Brüggemann’s Stations of the Cross (2014—in relation to questions of religious experience, the female body and film style. In both films the battle between these opposing categories is played out on the bodies of women—a paraplegic MS sufferer in Lourdes, an anorexic teen in Stations of the Cross—and both the films end ambiguously with what may, or may not, be a miracle of sorts: a confirmation of faith or a rebuttal. I wish to connect this ambiguity to the use of a very distinctive mise-en-scene in both films, which relies on a heavily restricted colour palate; highly formalised, painterly-compositions; and crucially what David Bordwell has termed “planimetric photography”: a shooting style that eschews depth or diagonals, refusing the spectator entrance into the image and holding her instead at a deliberate distance. My argument, in short, is that these stylistic choices—while gesturing towards a tradition of Christian art—also refuse the spectator either visual or haptic knowledge of the events that the characters undergo. Rather, they are suggestive of the fundamental unknowability that characterises religious experience, leaving us alone, outside of the action, forced to negotiate ourselves between belief and doubt.

Etude des propriétés rhéologiques des coupes lourdes à haute température et pression Study of the Rheological Properties of Heavy Cuts At High Temperature and Pressure

Directory of Open Access Journals (Sweden)

Cohen A.

2006-11-01

Full Text Available Les procédés rencontrés dans la valorisation des résidus et des huiles lourdes font appel à des équipements dont le dimensionnement optimal exige la connaissance précise des propriétés rhéologiques de la phase hydrocarbonée impliquée et ce, dans un large domaine de température et de pression. En conséquence, le Laboratoire de Thermodynamique du Centre Réacteurs et Processus de l'École Nationale Supérieure des Mines (ENSM de Paris s'est attaché au développement d'un viscosimètre approprié à ces mesures. Il est basé sur la détermination du couple résistant provoqué par le fluide à étudier, cisaillé entre deux cylindres coaxiaux en rotation relative. Le domaine de viscosité balayé s'étend de 10 à 40 000 cP, les température et pression maximales d'utilisation étant respectivement de 500°C et 30 MPa. La qualité des résultats fournis par cet appareillage a été testée, à des températures et dilution variables, sur quelques coupes lourdes issues des bruts Safaniya et Boscan après désasphaltage ou hydroviscoréduction. On obtient ainsi des valeurs fiables, reproductibles et précises de la viscosité des coupes lourdes hydrocarbonées sur un large domaine de température. Au-delà de 430-440°C toutefois, la pression opératoire de la cellule, fixée par la quantité du gaz admis, augmente brusquement, révélant un craquage thermique important des échantillons et offrant ainsi un moyen d'étude et de simulation des procédés industriels de viscoréduction. Processes used for the upgrading of residues and heavy oils makes use of equipment for which the optimal sizing requires the exact understanding of the rheological properties of the hydrocarbon phase involved over a wide temperature and pressure range. Therefore, the thermodynamics laboratory of the ENSM Center for Reactors and Processes has carried out the development of a viscosimeter suited for such measurements. It is based on determining the

Current signal of silicon detectors facing charged particles and heavy ions; Reponse en courant des detecteurs silicium aux particules chargees et aux ions lourds

Energy Technology Data Exchange (ETDEWEB)

Hamrita, H

2005-07-01

This work consisted in collecting and studying for the first time the shapes of current signals obtained from charged particles or heavy ions produced by silicon detectors. The document is divided into two main parts. The first consisted in reducing the experimental data obtained with charged particles as well as with heavy ions. These experiments were performed at the Orsay Tandem and at GANIL using LISE. These two experiments enabled us to create a data base formed of current signals with various shapes and various times of collection. The second part consisted in carrying out a simulation of the current signals obtained from the various ions. To obtain this simulation we propose a new model describing the formation of the signal. We used the data base of the signals obtained in experiments in order to constrain the three parameters of our model. In this model, the charge carriers created are regarded as dipoles and their density is related to the dielectric polarization in the silicon detector. This phenomenon induces an increase in permittivity throughout the range of the incident ion and consequently the electric field between the electrodes of the detector is decreased inside the trace. We coupled with this phenomenon a dissociation and extraction mode of the charge carriers so that they can be moved in the electric field. (author)

Heavy water moderated gas-cooled reactors; Filiere eau lourde - gaz

Energy Technology Data Exchange (ETDEWEB)

Bailly du Bois, B; Bernard, J L; Naudet, R; Roche, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

long terme de reacteurs rapides, s'est engagee egalement dans le developpement des reacteurs a eau lourde refroidis par gaz, qui semblent presenter les meilleures perspectives pour le moyen terme. L'economie de ces reacteurs, comme dans le cas du graphite, repose sur l'utilisation d'uranium naturel ou extremement peu enrichi. L'eau lourde permet d'en tirer le maximum d'avantages, tout en donnant lieu grace a ses performances plus poussees a des perspectives de developpement tres interessantes. Une centrale prototype EL 4 (70 MWe) est actuellement en construction: elle est decrite en detail dans un autre memoire. La presente communication fait le point du programme consacre en France au developpement de cette filiere. On indique d'abord quelles sont les raisons qui ont conduit a choisir ce type de reacteur: on montre l'Interet de la filiere, en soulignant ses atouts et ses difficultes. Passant en revue les principaux problemes technologiques et les travaux de developpement qui leur sont consacres, on analyse ensuite les resultats deja acquis et les points restant a confirmer. EL 4 est la premiere grande realisation: sa construction constitue une etape importante, aussi bien du point de vue demonstration de performances que possibilites d'experimentation et d'epreuve. Mais deja se pose le probleme de la conception d'une centrale de grande puissance unitaire. On a etudie a la fois l'adaptation ou l'amelioration des solutions mecaniques mises en oeuvre dans EL 4 et des variantes dont quelques-unes reposent sur des conceptions assez differentes. On indique ensuite quelles sont les caracteristiques envisagees pour une grande centrale dans l'etat actuel de la technique, compte tenu des etudes d'optimisation en cours. Des possibilites d'amelioration techniques existent d'ailleurs notamment en ce qui concerne les materiaux, ce qui pourrait conduire a des performances encore plus interessantes. Quelques perspectives a plus long terme sont evoquees. Finalement on aborde les

Swift heavy ion irradiation effects in {alpha} poly(vinylidene fluoride); Etude des effets induits par les ions lourds energetiques dans le poly(fluorure de vinylidene)

Energy Technology Data Exchange (ETDEWEB)

Le Bouedec, A

1999-11-29

The goal of this study is to characteristic and to localised defects created in {alpha} Poly (vinylidene fluoride) after swift heavy ion irradiations. PVDF films are irradiated with several Swift Heavy Ions (SHI), in the electronic stopping power (dE/dx){sub e}, in order to study the influence of irradiation parameters (absorbed dose, ion). These irradiated films are studied by different analysis techniques such as FTIR, ESR (X and Q band) spectroscopies and DSC. The crystalline level of PVDF is about 50% and we follow it destruction and amorphization as the absorbed dose increase by DSC and FTIR studies. The variation of the various FTIR bands allow us to observe the unsaturations induced by SHI radiations. Two sets of defects are observed: those which yield is sensitive to an increase of (dE/dx){sub e} and those that are not. A spatial distribution of the various defects within the talent track is provided and defects that are difficult to create are the closest of the ion path. The different kind of radicals created after irradiations are studied by ESR spectroscopy. Alkyl, peroxy and polyenyl radicals are detected after SHI radiations like after electron or {gamma} irradiations. Their yield of creation is independent of (dE/dx){sub e} and their localised in the crystalline zone or/and at the interfacial zone between crystalline and amorphous one. An other kind of radicals is created only after SHI radiations that are specific of the SHI-polymer interaction. We observe that these radicals are localised on a carbon cluster, in the core of the latent track for low doses and highly sensitive at the (dE/dx){sub e} of the ion. (author)

Overview and Computational Approach for Studying the Physicochemical Characterization of High-Boiling-Point Petroleum Fractions (350°C+ Approche informatique pour l’étude des propriétés physico-chimiques de fraction pétrolière lourde (350°C+

Directory of Open Access Journals (Sweden)

Plazas Tovar L.

2012-06-01

différents éléments. Ce travail présente une approche informatique qui peut être utilisée pour l’évaluation et l’estimation des propriétés des fractions pétrolières lourdes. La fraction pétrolière est divisée en un nombre arbitraire de pseudo-composants. Des cas d’étude ont été illustrés pour trois résidus lourds, issus d’un nombre égal de pétroles bruts “X, Y et Z”. La procédure nécessite en entrée le point d’ébullition, la courbe de distillation et la densité volumique de l’ensemble de la fraction lourde. Les méthodes existantes, issues des corrélations disponibles dans la littérature et des standards industriels, ont été principalement employées pour estimer les propriétés basiques (le point d’ébullition normal, la densité et facteur de caractérisation de Watson, les propriétés thermodynamiques (masse molaire et propriétés critiques et les propriétés thermophysiques (viscosité cinématique, conductivité thermique, capacité calorifique et pression de vapeur saturante. La méthode développée s’est montrée être un outil efficace pour calculer les propriétés des fractions pétrolières avec précision, quand les informations de départ sont disponibles. La prédiction des propriétés montre de bonnes correspondances avec les résultats obtenus auparavant dans les laboratoires de recherche LDPS/LOPCA de l’UNICAMP, avec un écart global absolu inférieur à 10 %.

Problems related with the power regulation of reactors by physico-chemical methods, and the behaviour of water and heavy water in nuclear reactors; Comportement de l'eau et de l'eau lourde dans les reacteurs nucleaires et problemes de la regulation de puissance par voie physico-chimique

Energy Technology Data Exchange (ETDEWEB)

Dolle, L; Conan, D; Dirian, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

Experience of the CEA heavy water reactors and a systematic study of the radiolytic decomposition of water in the core of swimming-pool reactors are described. Setting up of reactivity control by physico-chemical methods. Reactivity control by homogeneous poisoning of the reactor A comparison of the evolution of xenon poisoning with the residual anti reactivity of the poison in solution during its nuclear consumption establishes the programme which must govern the variation in its concentration if the exact compensation is to be produced The behaviour of the poison towards the reactor materials under the particular operational conditions must be taken into account. Radiolytic decomposition of water in the reactors in the presence of soluble poisons: A study of the effect of certain chemically inert salts, present in small concentrations in the water, on its radiolytic decomposition rate, has led to some new results which are discussed. The choice of a soluble poison is justified on the basis of the above results. Reactivity control by the use of a gaseous absorbent The use of a gas control rod circuit for compensation purposes, in place of solid control rods is described. The use of soluble poisons in the moderator to compensate the xenon effect, and of a gaseous absorbent in a circuit known as a gas control rod form original aspects of the reactivity control in the reactor EL 4. (authors) [French] L'observation du comportement de l'eau et de l'eau lourde dans les reacteurs en exploitation, contribue au fonctionnement sur de ceux-ci et oriente certaines etudes relatives aux techniques de controle de la reactivite par mise en oeuvre de poisons solubles. L'utilisation de poisons nucleaires dissous dans l'eau du reacteur entraine une pollution chimique de celle-ci. Les conditions d'emploi permettant d'eviter les effets indesirables de cette pollution sont etudiees. Les problemes analytiques - bien qu'importants - ne sont pas abordes dans le cadre de la communication

On the structure of heavy metals; Sur la structure des metaux lourds

Energy Technology Data Exchange (ETDEWEB)

Friedel, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Faculte des Sciences de l' Universite de Paris, 75 (France)

1958-07-01

The properties of the last series of Mendeleef's table are compared with those of the elements of the preceding series. This comparison suggests an electronic structure of the 'transition metal' type, with narrow bands, at the beginning of this series (up to certain phases at least of plutonium); then of the rare earth metal type, with independent non-saturated internal layers, further on in the series. The 5 f orbits seem to play an important part in these two types of structure, from uranium on. A more detailed study of the very heavy elements (americium and beyond) and alloys would allow these conclusions to be confirmed. Certain general points, concerning the nature of homopolar connections and paramagnetism in the transition metals, are developed in an additional section. (author) [French] Les proprietes des elements de la derniere serie du tableau de Mendeleef sont comparees a celles des elements des series precedentes. Cette comparaison suggere une structure electronique du type 'metal de transition', a bandes etroites, au debut de cette serie (jusqu'a certaines phases au moins du plutonium); puis du type d'un metal des terres rares, a couches internes non saturees independantes, au-dela dans la serie. Les orbitales 5 f semblent jouer un r e important, dans ces deux types de structures, a partir de l'uranium. Une etude plus poussee des elements tres lourds (americium et au-dela) et des alliages permettrait de confirmer ces conclusions. Certains points generaux, concernant la nature des liaisons homopolaires et le paramagnetisme dans les metaux de transition, sont developpes en annexe. (auteur)

L'hydrodésazotation des distillats issus de la conversion des hydrocarbures lourds Hydrodenitrogenation of Distillates Issuing from the Conversion of Heavy Hydrocarbons

Directory of Open Access Journals (Sweden)

Toulhoat H.

2006-11-01

Full Text Available L'hydrodésazotation catalytique (HDN est un des points clés de la valorisation des hydrocarbures lourds par leur conversion en carburants. Les coupes lourdes sont riches en azote, et leur conversion produit des distillats eux-mêmes très riches en azote, qui ne pourront être absorbés par une raffinerie classique sans un sévère prétraitement désazotant. Ce problème se pose quel que soit le procédé de conversion mis en oeuvre. On propose donc une analyse de l'HDN comprenant la description des structures azotées rencontrées dans les coupes à traiter, la mise en évidence des réactions à promouvoir, et les règles de choix de catalyseurs et de conditions opératoires en découlant compte tenu des principales déterminantes thermodynamiques et cinétiques. Cette analyse s'appuie sur des résultats de recherche très récents. Elle conduit à la mise en évidence de solutions actuelles au problème posé, et ouvre des perspectives pour des améliorations futures. Catalytic hydrodenitrogenation (HDN is one of the key steps in the upgrading of heavy hydrocarbons by converting them into fuels. Heavy cuts are rich in nitrogen, and their conversion produces distillates that are also very rich in nitrogen, making them unable to be absorbed by a conventional refinery without a severe denitrogenation pretreatment. This problem occurs no matter what conversion process is implemented. Therefore, an analysis of HDN is proposed, including the description of the nitrogen structures encountered in the cuts to be treated, the description of the reactions to be promoted, and the resulting rules for choosing catalysts and operating conditions, in the light of the principal thermodynamic and kinetic constraints. This analysis is based on very recent research results. It leads to the recommending of solutions to the problem at hand and opens up prospects for future improvements.

Calculation of the anti-trap factor in heavy water lattices; Calcul du facteur antitrappe dans les reseaux a eau lourde

Energy Technology Data Exchange (ETDEWEB)

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

1965-07-01

The calculation of the anti-trap factor of a lattice is complex when a large fraction of captures occurs in a range of energies where the spectrum in the fuel is considerably different from the simple dE/E law. This is particularly true for heavy water lattices in which the distances. between the bars are generally fairly large with respect to the slowing-down length. In order to take into account this effect it is necessary both to know the constitution of the effective resonance integral as a function of the energy, and to be able to calculate the distribution in the fuel. This report is devoted to these two problems. An improved method of treating the statistical domain makes it possible to plot the curves of the cross-sections per unit lethargy for various shapes of the fuel. Furthermore, the slowing-down of the neutrons is studied using a Monte-Carlo method which makes it possible in particular to take into account the perturbations caused by the non-moderating rods. A study is also made of the problem of shielding effects due to the captures themselves. (authors) [French] Le calcul du facteur antitrappe dans un reseau est complique lorsqu'une fraction importante des captures a lieu dans un domaine d'energie ou le spectre dans le combustible s'ecarte sensiblement de la loi simple en dE/E. Ceci est particulierement vrai pour les reseaux a eau lourde dans lesquels les distances entre barres sont en general assez grandes vis-a-vis de la longueur de ralentissement. Pour tenir compte de cet effet il faut connaitre d'une part la decomposition de l'integrale de resonance effective en fonction de l'energie, d'autre part savoir calculer le spectre dans le combustible. Le rapport est consacre a ces deux problemes. Un traitement ameliore du domaine statistique permet de tracer des courbes de sections de capture par unite de lethargie pour differentes geometries de barreaux. D'autre part le ralentissement des neutrons est etudie par une methode de Monte Carlo, qui permet

1167-IJBCS-Article-Mohammed El Kory

African Journals Online (AJOL)

DR GATSING

bicarbonates, les nitrites, les nitrates, l'ammonium, les sulfates, le fluorure et les métaux lourds (fer, zinc, chrome, cadmium, plomb et le cuivre). Les résultats des analyses physico-chimiques montrent que le pH est proche de la neutralité, il varie entre 7,1 et 7,6 ; la conductivité est élevée au niveau du forage d'El Arghoub.

Relation between hard photon production and impact parameter in heavy ion collisions at intermediate energies; Dependance de la production de photons durs avec le parametre d`impact dans les collisions entre ions lourds aux energies intermediaires

Energy Technology Data Exchange (ETDEWEB)

Martinez Garcia, G.

1994-06-01

Hard photons produced in heavy-ions collisions at intermediate energies have been used in order to study hot and compresses nuclear matter created in these collisions (at Ganil). It was found that Bremsstrahlung radiation emitted in np collisions is the main mechanism of hard-photon production for the whole range of impact parameter. Moreover, it was observed a substantial decrease of the hardness of hard-photon spectrum. The BUU model reproduces very well the experimental results, showing that the hardness of the spectrum reflects, mainly, nuclear-matter compression in the first stage of the collision. A new method was developed to measure the density of the nuclear matter created at the beginning of the collision. BUU results and some experimental evidences point out that a significant contribution of hard photons are produced in the last stage of the collision: thermal hard photons. These photons are sensitive to the density oscillation of nuclear matter. Its production cross-section will constitute a measurement of the compressibility of nuclear matter and its spectrum a measure of the temperature. (from author) 64 figs., 60 refs.

Petrochemical characteristics of Serra do Meio alkaline granite (Campo Alegre de Lourdes - Bahia State)

International Nuclear Information System (INIS)

Matos Maia Leite, C. de; Froes, R.J.B.

1989-01-01

The Serra do Meio granite outcrops near the town of Campo Alegre de Lourdes, north-northeast of Bahia State. The granite is intrusive into micachists, which are correlatives of the Salgueiro-Cachoeirinha Group (Early Proterozoic), during early to the syn-tectonic shear phase. The geological setting also comprises a phosphatic rock-bearing carbonatitic complex and gabbroid complexes with one of the main world resources of Fe-Ti-V. The granite mineralogical composition grades from Aegerine-augite alkali-feldspar granite/syenites to Leuco alcali-feldspar granite. The geochemical analysis shows SiO 2 -enrichment (67 to 76%), in alkalis (Na 2 +K 2 O, 7,5 to 12,5%), Nb (up to 680ppm), Zr (up to 2,390ppm), Y (up to 250ppm) e REE (up to 796ppm). The geochemical behaviour is peculiar to alkaline series, denoting a silica-oversaturated, potassium-rich, magma. The chondrite-normalized REE patterns display a first group with smooth slopes from the La to Lu, and a second one with negative slopes. Negative Eu anomalies are displayed in all the patterns. The first group is HREE-enriched, with low fractionation ratios. Samples with milonytic fabrics and higher fractionation ratios are related to the second group, suggesting the interaction of metassomatic fluids and the alkaline magma. Discriminant diagrams for Nb, Y and Rb, coupled with geophysical data, point to an intrusive granite in an extensional within a plate tectonic setting of attenuated continental crust. (author) [pt

L’excellence : impossible sans un personnel stable et expérimenté

CERN Multimedia

Association du personnel

2013-01-01

Le monde entier avait les yeux fixés sur le CERN ce 4 juillet 2012, quand ATLAS et CMS ont annoncé leur découverte d’une particule « compatible avec le Higgs ». Début 2013 il n’a fallu que quelques jours pour régler le LHC et faire tourner des protons et des ions lourds. Toutes ces découvertes et prouesses techniques n’ont été possibles que grâce à l’expérience et la poursuite de l’excellence d’équipes soudées de techniciens et ingénieurs qui ont conçu, construit, mis en marche, et finalement font fonctionner ce complexe d’accélérateurs unique au monde. Un service d’excellence avec un encadrement adéquat Entre 2002 et 2012 (voir Fig. 1), le nombre d’utilisateurs est passé de 5912 à...

Radiolysis of astrophysical ice analogs by energetic ions: the effect of projectile mass and ice temperature.

Science.gov (United States)

Pilling, Sergio; Duarte, Eduardo Seperuelo; Domaracka, Alicja; Rothard, Hermann; Boduch, Philippe; da Silveira, Enio F

2011-09-21

An experimental study of the interaction of highly charged, energetic ions (52 MeV (58)Ni(13+) and 15.7 MeV (16)O(5+)) with mixed H(2)O : C(18)O(2) astrophysical ice analogs at two different temperatures is presented. This analysis aims to simulate the chemical and the physicochemical interactions induced by cosmic rays inside dense, cold astrophysical environments, such as molecular clouds or protostellar clouds as well at the surface of outer solar system bodies. The measurements were performed at the heavy ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France. The gas samples were deposited onto a CsI substrate at 13 K and 80 K. In situ analysis was performed by a Fourier transform infrared (FTIR) spectrometer at different fluences. Radiolysis yields of the produced species were quantified. The dissociation cross section at 13 K of both H(2)O and CO(2) is about 3-4 times smaller when O ions are employed. The ice temperature seems to affect differently each species when the same projectile was employed. The formation cross section at 13 K of molecules such as C(18)O, CO (with oxygen from water), and H(2)O(2) increases when Ni ions are employed. The formation of organic compounds seems to be enhanced by the oxygen projectiles and at lower temperatures. In addition, because the organic production at 13 K is at least 4 times higher than the value at 80 K, we also expect that interstellar ices are more organic-rich than the surfaces of outer solar system bodies.

Atomic mixing of metallic bilayers Ni/Ti irradiated with high energy heavy ions; Etude du melange ionique de bicouches metalliques Ni/Ti irradiees avec des ions lourds de haute energie

Energy Technology Data Exchange (ETDEWEB)

Leguay, R

1994-09-26

We have studied the ionic mixing of Nl(105 angstrom) bilayers irradiated, at 80 and 300 K. with GeV heavy ions. In this energy range, the energy transfer from the incident ions to the target occurs mainly through electronic excitations. We have shown that this energy transfer induces a strong ionic mixing at the Nl/Ti interface. The thickness of the mixed interlayer increases with the fluence. At low fluences (10{sup 12} ions/cm{sup 2}), the Nl/Ti interface is rough ; at higher fluences (10{sup 13} ions/cm{sup 2}) a homogeneous mixed interlayer appears ; and at even higher fluences (some 10{sup 13} ions/cm{sup 2}) a preferential diffusion of Ni into Ti is clearly seen. The characterization techniques used are: (1) electrical resistivity measurements which allow to follow in situ the damage kinetic. (II) neutron and X-ray reflectometry. (III) elaboration of transverse cuts on which was performed energy loss spectroscopy. (II) and (III) allow the determination of the concentration profiles of the different species present in the sample. (IV) transmission electron microscopy on the transverse cuts which gives a direct image of the different layers. (author). 11 refs., 103 figs., 23 tabs., 2 appends.

Carbon ion irradiation of the human prostate cancer cell line PC3: A whole genome microarray study

Science.gov (United States)

SUETENS, ANNELIES; MOREELS, MARJAN; QUINTENS, ROEL; CHIRIOTTI, SABINA; TABURY, KEVIN; MICHAUX, ARLETTE; GRÉGOIRE, VINCENT; BAATOUT, SARAH

2014-01-01

Hadrontherapy is a form of external radiation therapy, which uses beams of charged particles such as carbon ions. Compared to conventional radiotherapy with photons, the main advantage of carbon ion therapy is the precise dose localization along with an increased biological effectiveness. The first results obtained from prostate cancer patients treated with carbon ion therapy showed good local tumor control and survival rates. In view of this advanced treatment modality we investigated the effects of irradiation with different beam qualities on gene expression changes in the PC3 prostate adenocarcinoma cell line. For this purpose, PC3 cells were irradiated with various doses (0.0, 0.5 and 2.0 Gy) of carbon ions (LET=33.7 keV/μm) at the beam of the Grand Accélérateur National d’Ions Lourds (Caen, France). Comparative experiments with X-rays were performed at the Belgian Nuclear Research Centre. Genome-wide gene expression was analyzed using microarrays. Our results show a downregulation in many genes involved in cell cycle and cell organization processes after 2.0 Gy irradiation. This effect was more pronounced after carbon ion irradiation compared with X-rays. Furthermore, we found a significant downregulation of many genes related to cell motility. Several of these changes were confirmed using qPCR. In addition, recurrence-free survival analysis of prostate cancer patients based on one of these motility genes (FN1) revealed that patients with low expression levels had a prolonged recurrence-free survival time, indicating that this gene may be a potential prognostic biomarker for prostate cancer. Understanding how different radiation qualities affect the cellular behavior of prostate cancer cells is important to improve the clinical outcome of cancer radiation therapy. PMID:24504141

The spectrographic analysis of inorganic impurities in heavy water; Analyse spectrographique des impuretes minerales dans l'eau lourde

Energy Technology Data Exchange (ETDEWEB)

Artaud, J; Normand, J [Commissariat a l' Energie Atomique, Service d' Analyses et de Recherches Chimiques Appliquees, Saclay (France). Centre d' Etudes Nucleaires; Vie, R [Commissariat a l' Energie Atomique, Service d' Etude de Traitement des Combustibles Irradies, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

Inorganic impurities in heavy water are determined by two spectrographic methods. First is described the copper-spark method which is sensitive and directly applicable, and is particular useful because of the absence of a support. Secondly the graphite impregnation method is given; this is used when the first method is not applicable (determination of copper) and for the alkali metals. For the usual elements, the sensitivity of the copper spark method is of the order of 0,1 {mu}g/ml whereas for the graphite impregnation method the sensitivity is only 0,3 {mu}g/ml. (author) [French] Les impuretes minerales dans l'eau lourde sont dosees au moyen de deux methodes spectrographiques. On decrit en premier lieu la methode 'copper spark' sensible directement applicable, et particulierement favorable du fait de l'absence de matrice. En second lieu, on decrit la methode d'impregnation du graphite, utilisee lorsque la methode precedente tombe en defaut (recherche du cuivre) et pour les alcalins. Avec la methode 'copper spark' nous obtenons pour les elements courants, des sensibilites de l'ordre de 0,1 {mu}g/ml, alors qu'elles ne sont que de 0,3 {mu}g/ml pour les alcalins doses a l'arc sur graphite impregne. (auteur)

Emission of H- fragments from collisions of OH+ ions with atoms and molecules

International Nuclear Information System (INIS)

Juhasz, Z.; Sulik, B.

2010-01-01

Compete text of publication follows. Detailed measurement of the kinematics of positive fragment ions from molecular collisions pro-vide useful information about the collision dynamics (see e.g. and references therein). In the present work, we turn our attention to negative fragments. Double differential emission spectra of negative charged particles have been measured in collisions of OH + ions with gas jets of Ar atoms and acetone (CH 3 -CO-CH 3 ) molecules at 7 keV impact energy. Among the emitted electrons, a relatively strong contribution of H - ions has been observed in both collision systems. According to a kinematic analysis, the observed H - ions were produced in close atom-atom collisions. For acetone, these ions originated from both the projectile and the target. The present ion impact energy range falls in the distal region of the Bragg peak. Therefore, a non negligible H - production in biological tissues could be relevant for ion therapy and for radiolysis in general. The present experiments were conducted at the 14.5 GHz Electron Cyclotron Resonance (ECR) ion source of the ARIBE facility, at the Grand Accelerateur National d'Ions Lourds (GANIL) in Caen, France. The molecular OH + ions were produced by introducing water vapor in the ECR plasma chamber. The extracted ions were collimated to a diameter of 2.5 mm before entering the collision chamber. In its center, the OH + projectiles crossed an effusive gas jet of either argon atoms or acetone molecules. In the collision area, the density of the gas target was typically of 10 13 cm -3 . The electrons and negative ions produced in the collision were detected by means of a single-stage spectrometer consisting of an electrostatic parallel-plate analyzer. Spectra taken at 30 deg observation angle are shown in Figure 1. Contributions from H - appear in clearly visible peaks. Kinematics shows that the peak at 410 eV in both panels is due emission of H - ions moving with nearly the projectile velocity. An H

Entre/Plantas

OpenAIRE

Montoro Coso, Ricardo; Sonntag, Franca Alexandra

2014-01-01

La palabra Inter-és proviene etimológicamente de las palabras latinas inter y esse; y significa “lo que está-entre dos o más personas, o sea lo que las une pero también las separa”. Los prefijos inter- y entre-, en la mayor parte de los casos, describen estados o acciones ambiguas de los términos que preceden. De esta operación aditiva surgen maclas de vocablos; el inter-sticio como la “hendidura o espacio que media entre dos cuerpos o entre dos partes de un mismo cuerpo”; y así sucesivamente...

Caractérisation des différents types de fibres musculaires dans plusieurs espèces : production et utilisation d'anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

OpenAIRE

Société Biocytex; Picard, Brigitte; Lefaucheur, Louis; Fauconneau, Benoit; Rémignon, Hervé; Cherel, Yan; Barrey, Eric; Nédelec, J.

1998-01-01

Des anticorps monoclonaux dirigés contre les chaînes lourdes de myosine (MHC : myosin heavy chain) de différentes espèces d’animaux : bovin, porc, poisson, poulet, dinde, cheval ont été produits. Ils ont été testés par immunohistologie sur des coupes de muscle squelettique chez le bovin, le porc, le poisson, le poulet et la dinde et par ELISA chez le cheval. Les différents anticorps retenus dans ce projet permettent de nouvelles applications pour l’étude du muscle squelettique. En particulier...

Heavy ion irradiation of crystalline water ice. Cosmic ray amorphisation cross-section and sputtering yield

Science.gov (United States)

Dartois, E.; Augé, B.; Boduch, P.; Brunetto, R.; Chabot, M.; Domaracka, A.; Ding, J. J.; Kamalou, O.; Lv, X. Y.; Rothard, H.; da Silveira, E. F.; Thomas, J. C.

2015-04-01

Context. Under cosmic irradiation, the interstellar water ice mantles evolve towards a compact amorphous state. Crystalline ice amorphisation was previously monitored mainly in the keV to hundreds of keV ion energies. Aims: We experimentally investigate heavy ion irradiation amorphisation of crystalline ice, at high energies closer to true cosmic rays, and explore the water-ice sputtering yield. Methods: We irradiated thin crystalline ice films with MeV to GeV swift ion beams, produced at the GANIL accelerator. The ice infrared spectral evolution as a function of fluence is monitored with in-situ infrared spectroscopy (induced amorphisation of the initial crystalline state into a compact amorphous phase). Results: The crystalline ice amorphisation cross-section is measured in the high electronic stopping-power range for different temperatures. At large fluence, the ice sputtering is measured on the infrared spectra, and the fitted sputtering-yield dependence, combined with previous measurements, is quadratic over three decades of electronic stopping power. Conclusions: The final state of cosmic ray irradiation for porous amorphous and crystalline ice, as monitored by infrared spectroscopy, is the same, but with a large difference in cross-section, hence in time scale in an astrophysical context. The cosmic ray water-ice sputtering rates compete with the UV photodesorption yields reported in the literature. The prevalence of direct cosmic ray sputtering over cosmic-ray induced photons photodesorption may be particularly true for ices strongly bonded to the ice mantles surfaces, such as hydrogen-bonded ice structures or more generally the so-called polar ices. Experiments performed at the Grand Accélérateur National d'Ions Lourds (GANIL) Caen, France. Part of this work has been financed by the French INSU-CNRS programme "Physique et Chimie du Milieu Interstellaire" (PCMI) and the ANR IGLIAS.

Formation and evolution of point defects created in alkali halogen compounds irradiated by heavy ions; Formation et evolution des defauts ponctuels crees dans certains halogenures alcalins irradies par des ions lourds

Energy Technology Data Exchange (ETDEWEB)

Hourdequin, E [Nantes Univ., 44 (France)

1993-07-16

The goal of this study was to achieve a better understanding of the heavy-ion material interaction. Alkali halogen crystals were chosen since the color centers produced by heavy ions can be distinguished easier from those generated by X rays. Measurements on KI irradiated at low temperature showed that the usual process of non radiative de-excitation of self-captured exciton is not prevailing. As the main objective of this work was the exact determination of the defects created by accelerated heavy ions, an important effort was dedicated to the spectrum deconvolution. Due to the high quality of the obtained spectra the V band analyse was possible. The defect stability was found to have the same nature in all the cubical alkali halogens and depend essentially on the crystal type. The defect evolution after irradiation is related to the diffusion coefficients corresponding to each mobile species and to the crystal lattice in which they move. Based on measurements made at different temperatures a simple modeling of the recombination kinetics was proposed. This effect was found to be specific to irradiation by heavy ions. It is difficult to determine the initial processes from the fossil defects, so, the defect history must be known as the described investigation methods do not permit to establish the transient aspect of defect creation. The important role of impurities should be stressed as the third intruder in the ion/crystal configuration; it can modify significantly the final state of the irradiated crystal, as it was found in KI, for instance. The open problems underlined in this study will probably be solved by using the atomic force microscopy and diffraction or on-line Raman measurements in ISOC chamber to avoid the passage to ambient conditions of the crystals irradiated at low temperatures 60 refs.

Study of heavy ions collision at SIS energies with the detector FOPI; Etude des collisions d'ions lourds aux energies de SIS avec le detecteur FOPI

Energy Technology Data Exchange (ETDEWEB)

Bastid, N

1999-09-23

The present work has been carried out in the framework of experiments performed with the FOPI detector at the SIS/ESR accelerator facility of GSI-Darmstadt. It is devoted to the study of central and semi-central heavy ion collisions at beam energies ranging from 100 MeV to 2 GeV per nucleon. We present first generalities on relativistic heavy ion collisions then the FOPI detector with a special attention to the FOPI Inner Wall constructed by the Clermont-Ferrand group. The main results of the FOPI collaboration obtained with light and intermediate mass fragments and kaons are presented. A systematic study of the different forms of collection motion of nuclear matter, radial flow in very central reactions, sideward flow and squeeze-out in semi-central collisions, is performed. Further exciting possibilities concerning production and propagation of strangeness at SIS energies will be offered soon with the upgrade of the FOPI detector. The FOPI data have introduced constraints on parameters of theoretical models. Important progress concerning the knowledge of the properties of nuclear matter, the dynamics of the collisions and in-medium effects have been achieved. (author)

Patients Attitude towards Surgeons Attire in Our Lady of Lourdes Hospital Drogheda

Directory of Open Access Journals (Sweden)

Babak Meshkat

2015-04-01

Full Text Available Background A doctor’s competence and professionalism is often judged on the basis of attire. Our Lady of Lourdes (OLOL is a leading Irish hospital in the implementation of Bare Below the Elbows (BBTE policy, however surgical attire is not standardised and there is great variability in attire worn on wards. We aimed to evaluate patients attitude towards surgeons attire in OLOL. Methods A prospective survey of adult surgical in-patients was conducted from October 2013 to February 2014. A twelve-question questionnaire was used as data collection tool, using a five point Likert scale to assess patients response to each question. Data were collected on patient demographics, patients level of trust and confidence based on different surgical attire, and patients perception of different attire worn by surgical teams. Results There were 150 completed surveys during the study period with a male to female ratio of 44% to 56% respectively. The mean patient length of in-hospital stay (LOS was 4.7 days (range 1–22. The most commonly represented age group was 30–40 years (18%, with a comparable spread among all age groups. The majority of patients found the attire worn by surgeons on the ward to be very appropriate (93%. Majority of responders believed scrubs to be the most appropriate attire for surgeons on wards (39%, followed by shirt and tie with white coat (38% followed by short sleeved shirt and no tie (18%. Shirt and tie with white coat had a positive effect on patients trust in 63% of responders, a negative effect in 10% and no effect in 26%. Scrubs had a positive effect on patients trust in 63%, negative effect in 11% and no effect in 25%. Short sleeved shirt and no tie had a positive effect in 44%, negative effect in 25% and no effect in 30% of patients. Conclusion Patients in OLOL find attire worn by surgeons to be appropriate. Shirt and tie with white coat or scrubs remains the patient’s choice attire for surgeons. Shirt and tie with white

Study of the degradation process of polyimide induced by high energetic ion irradiation

International Nuclear Information System (INIS)

Severin, Daniel

2008-01-01

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10 10 -5 x 10 12 ions/cm 2 ). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10 10 ions/cm 2 ). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO 2 , and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a critical material degradation which

Study of the degradation process of polyimide induced by high energetic ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Severin, Daniel

2008-09-19

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10{sup 10}-5 x 10{sup 12} ions/cm{sup 2}). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10{sup 10} ions/cm{sup 2}). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO{sub 2}, and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a

Transport de pétroles bruts lourds sous forme d'émulsion huile dans eau Transporting Heavy Crude Oils in Oil in Water Emulsions

Directory of Open Access Journals (Sweden)

Briant J.

2006-11-01

Full Text Available Des études préliminaires concernant le comportement visqueux d'émulsions d'un pétrole lourd très visqueux (Boscan, Venezuela dans de l'eau additionnée d'un tensioactif anionique ont été réalisées. Elles montrent que, pour la gamme des vitesses de cisaillement existant dans le transport par oléoduc, des réductions de viscosité de plusieurs ordres de grandeur par rapport à la viscosité du pétrole peuvent être obtenues avec des fractions volumiques de la phase dispersée de l'ordre de 60 %. This article describes a preliminary research on the viscous behavior of emulsions of a highly viscous heavy crude oil (Boscan, Venezuela in water containing an anionic surfactant. In the range of the shear rates usually encountered in pipelines, it is shown that the viscosity can be reduced by several orders of magnitude as compared with the crude oil viscosity, and th is for volume fractions of the dispersed phase in the range of 60%.

SiO{sub 2} on silicon: behavior under heavy ion irradiation; SiO{sub 2} sur silicium: comportement sous irradiation avec des ions lourds

Energy Technology Data Exchange (ETDEWEB)

Rotaru, C

2004-03-15

Heavy ion irradiation was performed on a-SiO{sub 2} layers deposited on Si. Damage of the surface was studied by means of Atomic Force Microscopy. Hillocks appear for an electronic stopping power higher than 16 keV/nm. The height of the hillocks decreases with the thickness of the oxide layer. Infrared Spectroscopy studies show that the damage threshold for a-SiO{sub 2} is at an electronic stopping power of 2 keV/nm. Therefore it is probable that the origin of the hillocks comes from the silicon layer. This could be explain within the frame of thermal spike model. The theoretical thresholds are 8 keV/nm and 1.8 keV/nm for silicon and a-SiO{sub 2} respectively. Chemical etching after irradiation gives a technical possibility to create nano-pits, whose size and shape can be controlled. Additionally, these structures allowed to determine the AFM tip radius. (author)

Étude de la compétitivité de complexation des métaux issus des ...

African Journals Online (AJOL)

Les analyses chimiques effectuées sur le phosphate naturel révèlent la présence des métaux lourds. Pour étudier les risques de rétrogradation de ces engrais phosphatés, notre étude s'est portée sur la complexation des substances humiques naturelles extraites des sols sur des ions métalliques tels que le calcium, ...

RF link for Implanted Medical Devices (IMDs) and Sub-GHz Inductive Power Transmission

OpenAIRE

Diet , Antoine; Koulouridis , Satvros; Le Bihan , Yann; Luu , Quang-Trung; Meyer , Olivier; Pichon , Lionel; Biancheri-Astier , Marc

2017-01-01

International audience; Ce travail s'inscrit dan sune etude exploratoire sur les possibilités de télé-alimentation RF des implants médicaux et/ou de communication entre eux. En effet, la durée de fonctionnement de certains implants avec batterie rend leur utilisation critique car il ne faut pas privilégier une intervention chirurgicale lourde s'il est possible d'agir de manière non-invasive. La transmission d'énergie sans fil ou WPT (Wireless Power Transfer) est au cœur de nombreuses autres t...

The Alice experiment for the study of ultra relativistic heavy ion collisions; Experience ALICE pour l'etude des collisions d'ions lourds ultra-relativistes au CERN-LHC

Energy Technology Data Exchange (ETDEWEB)

Forestier, B

2003-12-01

Alice is the detector dedicated to the study of heavy ions at the LHC (large hadron collider). It will allow scientists to investigate all the signatures of quark-gluon plasma (QGP). The spectrometer of the dimuon arm of Alice has been designed to study the production of high mass resonances through their dimuon decay. The first chapter is dedicated to some aspects of the physics of ultra-relativistic heavy ion: confinement and de-confinement of quarks, the absence of heavy resonances as a signature for the presence of QGP. The second chapter presents Alice and its ancillary detectors. The third chapter deals with the trigger system of the dimuon spectrometer, a detailed algorithm of this system is given. A method for the optimization of the trigger response is presented in the fourth chapter. The fifth chapter describes the testing of a prototype of the trigger system, this testing with muons has shown that the efficiency of the track reconstruction of the trigger system and the efficiency of the resistive plate chamber reach 98%.In the sixth chapter the author comments the simulations of the production of heavy resonances from Pb-Pb collisions as a function of centrality. (A.C.)

Characterization and performances of DOSION, a dosimetry equipment dedicated to radiobiology experiments taking place at GANIL

Energy Technology Data Exchange (ETDEWEB)

Boissonnat, Guillaume, E-mail: boissonnat@lpccaen.in2p3.fr [LPC (Normandie Univ-ENSICAEN-UNICAEN-CNRS/IN2P3), 6 Bd Maréchal Juin, 14050 Caen (France); Fontbonne, Jean-Marc [LPC (Normandie Univ-ENSICAEN-UNICAEN-CNRS/IN2P3), 6 Bd Maréchal Juin, 14050 Caen (France); Balanzat, Emmanuel [CIMAP (CEA/DSM-CNRS/INP-ENSICAEN-UNICAEN), Bd Henri Becquerel, 14076 Caen (France); Boumard, Frederic; Carniol, Benjamin [LPC (Normandie Univ-ENSICAEN-UNICAEN-CNRS/IN2P3), 6 Bd Maréchal Juin, 14050 Caen (France); Cassimi, Amine [CIMAP (CEA/DSM-CNRS/INP-ENSICAEN-UNICAEN), Bd Henri Becquerel, 14076 Caen (France); Colin, Jean; Cussol, Daniel; Etasse, David; Fontbonne, Cathy [LPC (Normandie Univ-ENSICAEN-UNICAEN-CNRS/IN2P3), 6 Bd Maréchal Juin, 14050 Caen (France); Frelin, Anne-Marie [GANIL (CEA/DSM-CNRS/IN2P3), Bd Henri Becquerel, 14076 Caen (France); Hommet, Jean; Salvador, Samuel [LPC (Normandie Univ-ENSICAEN-UNICAEN-CNRS/IN2P3), 6 Bd Maréchal Juin, 14050 Caen (France)

2017-06-01

Currently, radiobiology experiments using heavy ions at GANIL (Grand Accélérateur National d′Ions Lourds) are conducted under the supervision of the CIMAP (Center for research on Ions, MAterials and Photonics). In this context, a new beam monitoring equipment named DOSION has been developed. It allows to perform measurements of accurate fluence and dose maps in near real time for each biological sample irradiated. In this paper, we present the detection system, its design, performances, calibration protocol and measurements performed during radiobiology experiments. This setup is currently available for any radiobiology experiments if one wishes to correlate one's own sample analysis to state-of-the-art dosimetric references.

Relationship between Statistical and Dynamical properties of fragments produced at Fermi Energy in Heavy ion collisions: ng; Liens entre les proprietes statistiques et dynamiques des fragments produits lors des collisions d'ions lourds autour de l'energie de Fermi

Energy Technology Data Exchange (ETDEWEB)

Lehaut, G.

2009-10-15

The properties of the fragments produced in heavy-ion collisions around the Fermi energy have been studied through the isospin degree of freedom. First, a theoretical approach based on a lattice gas model with two types of particles (neutron,proton) interacting by an isospin dependent and Coulomb interactions was developed. The study of the phase diagram shows that this system presents three different phases (liquid, gas, fission). In the liquid and gas phases, the energy of the system was described by a density functional, where the temperature dependence acts only on the density. The symmetry term of this functional was related to the isotopic content of the biggest fragment via an iso-scaling analysis. Secondly a systematic study of the stopping power of the nuclear matter and isospin equilibration of light particles in the most violent collisions was carried out using the experimental data taken by the INDRA multidetector at GANIL and GSI. Two stopping power regimes appear; at low energy (< 40 MeV/A) the stopping power decreases with increasing beam energy, whereas at high energy the stopping power is governed by the quantity of matter along the beam direction. An other study has been focused on the Xe+Sn reaction at 32 and 45 MeV/A with different isospin systems. The separation of three different reaction mechanisms by use of a principal component analysis allowed us to observe that the isospin content of light particles seems to be independent on the mechanism, but depends on the violence of the collision (i.e. impact parameter). (author)

Clinical audit of patients with cerebrovascular accident and transient ischemic attack in our lady of lourdes hospital drogheda, ireland

International Nuclear Information System (INIS)

Nagi, D.; Aamar, A.; Rahim, I.; Sadaf, M.I.

2012-01-01

Stroke is a major health problem and is one of leading causes of morbidity and mortality. Methods: A clinical audit comprising retrospective chart review of 101 patients randomly selected from admission register in Our Lady of Lourdes Hospital Drogheda, Ireland, was done during the first quarter of 2009. Keeping in view the recommendations, in this audit the following areas were evaluated: type of event, time of event and arrival to hospital, thrombolytic therapy, past medical history, investigations, smoking history, utilization of multidisciplinary services (physiotherapy and occupational therapy, speech and language therapy), medications, referral to GP, carotid pathology, and outcome. Results: Of the 101 patients, 43 (42.5%) were males and 58 (57.4%) were females. 47.5% (48/101) had TIA while 52.5% (53/101) had CVA. Of the total patients, 62.8% males and 56.8% females were hypertensive and 48.8% of males and 36.2% of females had hypercholesterolemia. Of the total number of patients, 23% of males and 15.5% of females were smokers. Utilization of different multidisciplinary services for males and females was following: physical therapy (46.5% and 45.8%); occupational therapy (11.6% and 15.3%); speech and language therapy (13.9% and 22%). Of all the patients 5% died in the hospital, 77.2% were discharged home and 17.8% were sent to Nursing home for long term care. Conclusion: The commonest risk factor for CVA / TIA is hypertension followed by hypercholesterolemia. Smoke cessation advice should be given to all at risk. (author)

Fusion-Fission process and gamma spectroscopy of binary products in light heavy ion collisions (40 {<=} A{sub CN} {<=} 60); Processus de fusion-fission et spectroscopie gamma des produits binaires dans les collisions entre ions lourds legers (40 {<=} A{sub NC} {<=} 60)

Energy Technology Data Exchange (ETDEWEB)

Nouicer, Rachid [Institut de Recherche Subatomique, CNRS-IN2P3 - Universite Louis Pasteur, 67 - Strasbourg (France)

1997-11-21

During the work on which this Thesis is based, the significant role of the Fusion-Fission Asymmetric mechanism in light heavy ion collisions (A{sub NC} {<=} 60) has been emphasized. The Spin Dis-alignment in the oblate-oblate system has supplied evidence for the first time for the Butterfly mode in a resonant-like reaction. These two aspects, one macroscopic and the other more closely related to microscopic effects are certainly different from a conceptual point of view but are quite complementary for a global understanding of dinuclear systems. In the first part, inclusive and exclusive measurements of the {sup 35}Cl + {sup 12}C and {sup 35}Cl + {sup 24}Mg reaction have been performed at 8 MeV/nucleon in the Saclay experiment. These measurements have permitted us to verify the origin of products which have given rise of the asymmetric fusion-fission mechanism and which have demonstrated that the three-body process in this energy range is very weak. In the second part the {sup 28}Si + {sup 28}Si reaction has been performed at the resonance energy E{sub lab}> = 111.6 MeV at Strasbourg with the Eurogam phase II multi-detector array and VIVITRON accelerator. An angular momentum J{sup {pi}} 38{sup +} for inelastic and mutual channels of the {sup 28}Si + {sup 28}Si exit channel has been measured and has supplied evidence for a spin dis-alignment which has been interpreted in the framework of a molecular model by Butterfly motion. The spectroscopic study of {sup 32}S nucleus, has revealed the occurrence of a new {gamma}-ray transition 0{sup +}(8507.8 keV) {yields} 2{sub 1}{sup +}(2230.2 keV). (author) 105 refs., 116 figs., 26 tabs.

Improvement of Heavy Oil Recovery in the VAPEX Process using Montmorillonite Nanoclays Amélioration de la récupération d’huile lourde par utilisation de nanoargiles de Montmorillonite dans le procédé VAPEX

Directory of Open Access Journals (Sweden)

Pourabdollah K.

2011-10-01

Full Text Available In this paper, the nanoclay particles were introduced as mobile adsorbents in oil reservoirs to adsorb the asphaltenes, reduce the viscosity and enhance the dispersion. The objective of this paper is experimental investigation of enhanced heavy oil recovery using in situ nanoparticles for the first time. Moreover, two thermal analysis methods (thermogravimetry and differential thermal analysis were used to analyze the asphaltene content of residue hydrocarbons in the swept chambers in nano-assisted and conventional VAPEX processes. Experiments were carried out using Iranian heavy oil and propane: the setup consisted of two sand-packed cells; one packed only with glass beads as the oil matrix and the other with glass beads and modified montmorillonite as the nanoclay, while they had similar porosity and permeability. The content of deposited asphaltene in swept matrixes, the propagation pattern of vapor chambers in heavy oil matrixes, and the rates of solvent consumption and oil production were determined. The results elucidated that montmorillonite changed the matrix heterogeneity and led to forming enhanced breakthroughs, to increasing the interfacial surface of vapor/bitumen and to accelerating the oil production. It was found that not only was the rate of vapor injection diminished, but the heavy oil recovery was also markedly enhanced by 30(±4%. Dans cet article, on decrit l’utilisation de particules de nanoargile en tant qu’adsorbant mobile dans des reservoirs d’huile afin d’adsorber les asphaltenes, reduire la viscosite de l’huile et renforcer la dispersion. L’objectif de cet article consiste en la description d’une etude experimentale de recuperation amelioree d’huile lourde par l’utilisation de nanoparticules in situ. Ce qui constitue une premiere. En outre, deux methodes d’analyse thermique (thermogravimetrie et analyse thermique differentielle ont ete utilisees pour analyser la teneur en asphaltene des residus d�

Le détecteur VZERO, la physique muons présente et la préparation de son futur dans l'expérience ALICE au LHC

CERN Document Server

Tieulent, Raphaël

La physique des ions lourds a pour objectif ultime d'étendre le domaine d'application du Modèle Standard de la physique des particules à des systèmes de taille finie, complexes et dynamiques. En particulier, elle vise à comprendre comment apparaissent, à partir des lois microscopiques de la physique des particules élémentaires, des phénomènes collectifs et des propriétés macroscopiques mettant en jeu un grand nombre de degrés de liberté. La réalisation de ce programme scientifique passe par une caractérisation du plasma de quarks et de gluons (QGP), l'état déconfiné de la matière nucléaire qui peut être formé à l'aide de collisions d'ions lourds accélérés à des énergies ultra relativistes. L'expérience ALICE exploite les collisions Pb-Pb, proton-Pb et proton-proton du LHC pour mesurer les propriétés fondamentales du QGP comme, par exemple, la température critique du déconfinement ou les coefficients de transport de la matière déconfinée. L'état QGP de la matière aurait �...

Contribution to the study of sputtering and damage of uranium dioxide by fast heavy ions; Contribution a l'etude de la pulverisation et de l'endommagement du dioxyde d'uranium par les ions lourds rapides

Energy Technology Data Exchange (ETDEWEB)

Schlutig, S

2001-03-01

Swift heavy ion-solid interaction leads in volume to track creation and on the surface to the ejection of particles into the vacuum. To learn more about initial mechanisms of track formation, we are focused on the sputtering of uranium dioxide by fast heavy ions. This present study is exclusively devoted to the influence of the electronic stopping power on the emission of neutral particles and especially on their angular distribution. These measurements are completed by those of the ions emitted from UO{sub 2} targets bombarded with swift heavy ions. The whole experimental results give access to: i) the nature of the sputtered particles; ii) the charge state of the emitted particles; iii) the direction of ejection of the sputtered particles ; iv) the sputtering yields deduced from the angular distributions. These results are compared to the prediction of the sputtering models proposed in the literature and it seems that the supersonic gas flow model is well suited to describe our results. Finally, the sputtering yields are compared with a set of earlier experimental data on uranium dioxide damage obtained by T. Wiss and we observe that only a small fraction of UO{sub 2} monolayers are sputtered. (author)

Separation of lithium isotopes on ion exchangers; Separation des isotopes du lithium sur echangeurs d'ions

Energy Technology Data Exchange (ETDEWEB)

Menes, F; Saito, E; Roth, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

A survey of the literature shows that little information has been published on the separation of lithium isotopes with ion exchange resins. We have undertaken a series of elutions using the ion-exchange resins 'Dowex 50 x 12' and IRC 50, and various eluting solutions. Formulae derived from the treatment of Mayer and Tompkins permit the calculation of the separation factor per theoretical plate. For the solutions tried out in our experiments the separation factors lie in the interval 1.001 to 1.002. These values are quite low in comparison to the factor 1.022 found by Taylor and Urey for ion exchange with zeolites. (author) [French] Nous avons trouve relativement peu de donnees dans la litterature scientifique sur la separation des isotopes de lithium par les resines echangeuses d'ions. Nous avons effectue un certain nombre d'essais sur Dowex 50 X 12 et IRC 50 utilisant divers eluants. Des formules derivees de celles de Mayer et Tompkins permettent le calcul du coefficient de separation par plateau theorique. Pour les eluants etudies, ces facteurs de separation se trouvent entre 1,001 et 1,002. Ces valeurs sont faibles en comparaison du facteur 1,022 trouve par Taylor et Urey pour les zeolithes. (auteur)

Study of the secondary electron emission during bombardment of metal targets by positive D{sup +} and D{sub 2}{sup +} ions (1960); Etude de l'emission secondaire d'electrons au cours du bombardement de cibles metalliques par des ions positifs D{sup +} et D{sub 2}{sup +} (1960)

Energy Technology Data Exchange (ETDEWEB)

Leroy, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Prelec, K [Institut Rudjer Boskovic, Zagreb (Croatia)

1960-07-01

The secondary electron yield {gamma}-bar due to primary positive ions D{sup +} and D{sup +}{sub 2} has been measured in the 70 keV to 300 keV ion energy range. Several metallic targets have been used. The variation of this yield with the angle of incidence is proportional to sec {theta} where {theta} is the angle between the beam of primary ions and the normal to the target surface. The values {gamma}-bar decrease for increasing energy ions. At a given energy all the targets tried gave approximately the same electron yield. (author) [French] Le facteur d'emission secondaire a ete mesure pour des ions positifs D{sup +} et D{sup +}{sub 2} ayant une energie comprise entre 70 keV et 300 keV, sur differentes cibles metalliques. La variation de ce facteur avec l'angle d'incidence suit une loi de la forme {gamma}{sub 0} sec {theta}, {theta} etant l'angle entre le faisceau et la normale a la cible. Les valeurs de {gamma}-bar trouvees decroissent lorsque l'energie des ions incidents augmente, mais sont assez voisines les unes des autres, a une energie donnee, pour les differentes cibles essayees. (auteur)

Effets Josephson generalises entre antiferroaimants et entre supraconducteurs antiferromagnetiques

Science.gov (United States)

Chasse, Dominique

L'effet Josephson est generalement presente comme le resultat de l'effet tunnel coherent de paires de Cooper a travers une jonction tunnel entre deux supraconducteurs, mais il est possible de l'expliquer dans un contexte plus general. Par exemple, Esposito & al. ont recemment demontre que l'effet Josephson DC peut etre decrit a l'aide du boson pseudo-Goldstone de deux systemes couples brisant chacun la symetrie abelienne U(1). Puisque cette description se generalise de facon naturelle a des brisures de symetries continues non-abeliennes, l'equivalent de l'effet Josephson devrait donc exister pour des types d'ordre a longue portee differents de la supraconductivite. Le cas de deux ferroaimants itinerants (brisure de symetrie 0(3)) couples a travers une jonction tunnel a deja ete traite dans la litterature Afin de mettre en evidence la generalite du phenomene et dans le but de faire des predictions a partir d'un modele realiste, nous etudions le cas d'une jonction tunnel entre deux antiferroaimants itinerants. En adoptant une approche Similaire a celle d'Ambegaokar & Baratoff pour une jonction Josephson, nous trouvons un courant d'aimantation alternee a travers la jonction qui est proportionnel a sG x sD ou fG et sD sont les vecteurs de Neel de part et d'autre de la jonction. La fonction sinus caracteristique du courant Josephson standard est donc remplacee.ici par un produit vectoriel. Nous montrons que, d'un point de vue microscopique, ce phenomene resulte de l'effet tunnel coherent de paires particule-trou de spin 1 et de vecteur d'onde net egal au vecteur d'onde antiferromagnetique Q. Nous trouvons egalement la dependance en temperature de l'analogue du courant critique. En presence d'un champ magnetique externe, nous obtenons l'analogue de l'effet Josephson AC et la description complete que nous en donnons s'applique aussi au cas d'une jonction tunnel entre ferroaimants (dans ce dernier cas, les traitements anterieurs de cet effet AC s'averent incomplets). Nous

Contribution to the study of rare earth separation by ion exchange, using ammonium lactate; Contribution a l'etude de la separation des terres rares par echange d'ions a l'aide de lactate d'ammonium

Energy Technology Data Exchange (ETDEWEB)

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

1958-07-01

Using the technique of chromatography on a column of Dowex 50 resin, heated to 87 deg. C, we have studied the separation of rare earths (from holmium to praseodymium) which may be produced with the cyclotron by heavy ions, {alpha} or protons. From an ammonium lactate solution M at pH 5, separations are carried out by varying the dilution as a function of the quantity of the target rare earth and of its position during elution. When weighable quantities of the rare earth (more than 5 mg) appear towards the end of the elution, the separation is little affected this case approaches that of a tracer mixture of rare earths; if on the other hand weighable quantities of the rare earth are washed through at the beginning of the chromatogram, the dilution must be adjusted in order to obtain a good separation. (author) [French] Par chromatographie sur colonne de resine Dowex 50, chauffee a 87 deg. C, nous avons examine la separation des terres rares (de l'holmium au praseodyme) susceptibles d'etre produites au cyclotron par ions lourds, {alpha} ou protons. A partir d'une solution de lactate d'ammonium M a pH 5, nous effectuons les separations en agissant sur la dilution en fonction de la quantite de terre rare cible et de sa position au cours de l'elution. Lorsque la terre rare en quantite ponderale (superieure a 5 mg) passe en fin d'elution, la separation est peu affectee; nous sommes ramenes au cas d'un melange de terres rares traceur; par contre, si la terre rare en quantite ponderale s'elue en tete du chromatogramme, nous devons agir sur la dilution pour obtenir une bonne separation. (auteur)

Study of elementary transfer mechanisms during a collision between a swift multi-charged heavy ion and a neutral atom; Etude des mecanismes elementaires de transfert d`energie au cours d`une collision entre un ion lourd rapide multi-charge et un atome neutre

Energy Technology Data Exchange (ETDEWEB)

Jardin, P. [Caen Univ., 14 (France)

1995-12-31

This work is dedicated to the study of the energy transfer mechanisms which occur during a collision between a swift multicharged heavy ion and a neutral atom. The elementary energy energy transfer mechanisms (scattering, excitation, ionization, capture) and their consequences on the target velocity after the collision (recoil velocity) are recalled in the first chapter. In the case of small projectile diffusion angles, we show that the recoil velocity component, transverse to the incident projectile direction, results principally from the diffusion mechanism, while the longitudinal component is due essentially to the mass transfer and the inelastic energy transfer mechanisms. Since the target recoil velocities are very small, we have built an experimental set-up which reduces the impreciseness on their measurement due to the target thermal spread using, as targets, cooled atoms of a supersonic jet (temperature < 1 K). The association of time of flight and localisation techniques allows us, for each ionised target atom, to determine the three recoil velocity components with a very good accuracy (a few tens of meters per second). In chapter three, we describe the data analysis method. And then we present in the last chapter the results we have obtained for the collision systems Xe{sup 44+}(6.7 MeV/A) + Ar => Xe{sup 44} + Ar{sup q+}+qe{sup -} (q ranging from 1 to 7); Xe{sup 44+} (6.7 MeV/A) + He => Xe{sup 44+} He{sup 1+,2+}+1e{sup -},2e{sup -}. We show that it is possible to interpret the recoil velocity in terms of kinetic energy transferred to the target and to the electrons ejected from the target. (author) 44 refs.

Contribution à l'étude de l'immobilisation des ions plomb en solution ...

African Journals Online (AJOL)

DK

mesurée à l'aide d'un granulomètre laser. (MASTER .... 91. Tableau 1. Composition chimique de PN en poids. Elets P2O5. CaO. MgO CO2. SiO2 .... interactions entre adsorbats ..... heavy metal ions from water by using calcined phosphate.

Operation and machine studies

International Nuclear Information System (INIS)

1992-01-01

This annual report describes the GANIL (Grand accelerateur national d'ions lourds, Caen, France) operation and the machine studies realized in 1992. Metallic ions have been accelerated during 36 pc of the time; some were produced for the first time at GANIL: 125 Te, 52 Cr with ECR3, 181 Ta with ECR4. The various machine studies are: comparison of lifetimes of carbon sheets, charge exchange of very heavy ions in carbon foils and in the residual gas of the Ganil cyclotrons, commissioning of the new high intensity axial injection system for Ganil, tantalum acceleration with the new injector, a cyclotron as a mass spectrometer; other studies concerned: implementing the new control system, gettering flux measurement, energy deposited by neutrons and gamma rays in the cryogenic system of SISSI; latest developments on multicharged ECR ion sources, and an on-line isotopic separator test bench at Ganil

Endostatin (EntreMed).

Science.gov (United States)

Grosios, K

2000-07-01

EntreMed has licensed the worldwide rights to the angiogenesis inhibitor Endostatin, a 20 kDa C-terminal fragment of collagen XVIII, from the Children's Hospital of Boston, a teaching affiliate of Harvard Medical School. It is being developed as a potential cancer treatment and may also be useful in certain types of blindness and arthritis [227427]. EntreMed filed an IND for Endostatin in June 1999 [334125] and as of September 1999, phase I trials were underway [341462]. As of April 2000, the company had initiated plans for testing low doses of Endostatin in cancer patients using continuous infusion and sc administration in a further phase I study to be conducted in Europe [361594]. A phase I trial of Endostatin which will evaluate the safety and efficacy of Endostatin at a range of doses in no more than 100 cancer patients has been initiated. The trial will take place at the University of Texas MD Anderson Medical Center and the University of Wisconsin Cancer Center in Madison. The National Cancer Center will be sponsoring the trial, which is expected to be completed in late 2000. As of March 2000, there had been no serious adverse events attributable to Endostatin administration. The first report from this trial is expected in autumn 2000 [341462], [366312]. The mechanism of action for Endostatin remains unclear, although reports from the 91st AACR Meeting in April 2000 showed that recombinant human endostatin bound to a number of tropomyosin cDNAs in a library screen [362039]. In preclinical studies, repeated administration of Endostatin consistently shrank primary tumors and did not produce any drug resistance. In mice, a variety of tumors which had progressed to 1 to 2% of total body weight, regressed to microscopic, dormant lesions following Endostatin treatment [231418], [231470], [270673]. Types of cancers which respond to Endostatin include lung, skin, vascular and fibrosarcomas. Toxicology studies in cynomolgus monkeys showed that bolus injections of

Pore-Level Investigation of Heavy Oil Recovery using Steam Assisted Gravity Drainage (SAGD Étude à l’échelle des pores de la récupération d’huiles lourdes par drainage gravitaire assisté par injection de vapeur (SAGD

Directory of Open Access Journals (Sweden)

Mohammadzadeh O.

2010-12-01

entrapment of steam due to the capillarity followed by condensation, steam condensation at the interface due to temperature gradient, and snap-off of liquid films are also illustrated using glass micromodels in pore-level visualization experiments. L’application réussie du procédé de drainage gravitaire assisté par injection de vapeur à l’aide de puits horizontaux lors de divers essais de champ, essentiellement au Canada, montre qu’on peut atteindre un taux de récupération élevé et des rapports vapeur injectée/pétrole récupéré économiquement viables. Le procédé de récupération par SAGD a été développé sur le plan théorique, testé sur pilote et commercialisé, tout cela au Canada; il reste cependant encore plusieurs problèmes techniques à résoudre dans ce procédé. Les phénomènes qui se développent à l’échelle des pores lors de la récupération d’huiles lourdes à l’aide du procédé SAGD ne sont pas encore très bien compris, ce qui conduit à intégrer la physique du processus au niveau des pores dans des modèles mathématiques. L’étude à l’échelle des pores des phénomènes physiques concernant la distribution des fluides et les types d’écoulement dans le milieu poreux dans ce procédé devrait apporter une nette amélioration de la compréhension des phénomènes macroscopiques observés aussi bien en laboratoire que sur le terrain. L’objectif principal de cet article est l’étude visuelle et la description des phénomènes à l’échelle des pores par l’utilisation d’un micromodèle en verre. Des expériences de SAGD ont été effectuées au laboratoire sur des micromodèles de réseaux capillaires gravés sur des plaques de verre qui, au départ, ont été saturés d’huile lourde. Ces expériences furent réalisées dans une chambre à vide pour éviter des pertes de chaleur excessives vers l’extérieur. Les premiers résultats montrent que lorsque l’interface huile lourde/vapeur est établie, un

Comparative Ebulliometry: a Simple, Reliable Technique for Accurate Measurement of the Number Average Molecular Weight of Macromolecules. Preliminary Studies on Heavy Crude Fractions Ébulliométrie comparative : technique simple et fiable pour déterminer précisément la masse molaire moyenne en nombre des macromolécules. Etudes préliminaires sur des fractions lourdes de bruts

Directory of Open Access Journals (Sweden)

Behar E.

2006-12-01

Full Text Available This article is divided into two parts. In the first part, the authors present a comparison of the major techniques for the measurement of the molecular weight of macromolecules. The bibliographic results are gathered in several tables. In the second part, a comparative ebulliometer for the measurement of the number average molecular weight (Mn of heavy crude oil fractions is described. The high efficiency of the apparatus is demonstrated with a preliminary study of atmospheric distillation residues and resins. The measurement of molecular weights up to 2000 g/mol is possible in less than 4 hours with an uncertainty of about 2%. Cet article comprend deux parties. Dans la première, les auteurs présentent une comparaison entre les principales techniques de détermination de la masse molaire de macromolécules. Les résultats de l'étude bibliographique sont rassemblés dans plusieurs tableaux. La seconde partie décrit un ébulliomètre comparatif conçu pour la mesure de la masse molaire moyenne en nombre (Mn des fractions lourdes des bruts. Une illustration de l'efficacité de cet appareil est indiquée avec l'étude préliminaire de résidus de distillation atmosphérique et de résines. En particulier, la mesure de masses molaires pouvant atteindre 2000 g/mol est possible en moins de 4 heures avec une incertitude expérimentale de l'ordre de 2 %.

Simulation of a relativistic heavy ions beam transport in the matter: contribution of the fragmentation process and biological implications; Simulation du transport d`un faisceau d`ions lourds relativistes dans la matiere: contribution du processus de fragmentation et implication sur le plan biologique

Energy Technology Data Exchange (ETDEWEB)

Ibnouzahir, M

1995-03-01

The study of relativistic heavy ion collisions permit an approach of the properties of dense and not hadronic matter, and an analysis of the reaction mechanisms. Such studies are also interesting on the biological point of view, since there exist now well defined projects concerning the radiotherapy with high LET particles as neutrons, protons, heavy ions. It is thus necessary to have a good understanding of the processes which occur in the propagation of a relativistic heavy ion beam (E{>=} 100 A.MeV) in matter. We have elaborated a three dimensional transport code, using a Monte Carlo method, in order to describe the propagation of Ne and Ar ions in water. Violent nuclear collisions giving fragmentation process have been taken into account by use of the FREESCO program. We have tested the validity of our transport model and we show an important change of the energy deposition at the vicinity of the Bragg peak; such a distortion, due mainly to fragmentation reactions, is of a great interest for biological applications. (author).

Le Parti des Paysans de Bessarabie et la rivalite entre Pantelimon Halippa et Ion Inculeţ

Directory of Open Access Journals (Sweden)

Andrei Cemârtan

2011-12-01

Full Text Available L’effervescence du mouvement national en Bessarabie en 1917 a apporté en premier plan la question de l’organisation de la vie politique. Anterieurement il n’y avait pas des partis politiques proprement dits et en étant animés par le meme but, les leaders de ce mouvement ont formé Le Parti National Moldave. Halippa a été un des représentants marquants qui a contribué à la formation de la vie politique en Bessarabie, il a fondé le Parti National Moldave, ulterieurement transformé en Parti des Paysans de Bessarabie, dont Halippa a été le président durant toute sa vie (1918-1926. Cet étude souligne le rôle joué par Halippa dans Le Parti des Paysans de Bessarabie et sa contribution à la fusion avec le Parti des Paysans dans le Vieux Royaume. Le conflit d’opinions entre Halippa et Inculeţ et, plus précisément le conflit entre les visions liés à l’avenir du parti, ont influencé l’évolution de l’organisation. L’intégration du Parti des Paysans de Bessarabie dans le système politique roumain a été la suite naturelle de l’Union et des processus complexes de formation de la Grande Roumanie, mais la formation d’un parti des paysans uni a représenté un progrès pour la vie politique roumaine.

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)

2016 Accelerators meeting

International Nuclear Information System (INIS)

Spiro, Michel; Revol, Jean-Luc; Biarrotte, Jean-Luc; Napoly, Olivier; Jardin, Pascal; Chautard, Frederic; Thomas, Jean Charles; Petit, Eric

2016-09-01

The Accelerators meeting is organised every two years by the Accelerators division of the French Society of Physics (SFP). It brings together about 50 participants during a one-day meeting. The morning sessions are devoted to scientific presentations while the afternoon is dedicated to technical visits of facilities. This document brings together the available presentations (slides): 1 - Presentation of the Ganil - Grand accelerateur national d'ions lourds/Big national heavy-ion accelerator, Caen (Jardin, Pascal); 2 - Presentation of the Accelerators division of the French Society of Physics (Revol, Jean-Luc); 3 - Forward-looking and Prospective view (Napoly, Olivier); 4 - Accelerators at the National Institute of Nuclear and particle physics, situation, Forward-looking and Prospective view (Biarrotte, Jean-Luc); 5 - GANIL-SPIRAL2, missions and goals (Thomas, Jean Charles); 6 - The SPIRAL2 project (Petit, Eric)

Influence sur les imbrûlés solides de composés métalliques particuliers et du taux de dispersion des asphaltènes dans les fuels lourds Influence of Unburned Solids Made of Unusual Metal Compounds and of the Asphaltene Dispersion Rate in Heavy Fuel Oils

Directory of Open Access Journals (Sweden)

Audibert F.

2006-11-01

Full Text Available La diversité croissante des origines de bruts a conduit, en combustion, a prendre en considération dans les modèles la teneur en métaux en plus du carbone Conradson ou des asphaltènes au C7 dans les fuels lourds. De tels modèles ont été développés par Exxon (1979 et Shell (1981 notamment. Des travaux récents faits à l'Institut Français du Pétrole (IFP sur une chaudière de 2 MW ont montré l'influence de composés métalliques particuliers présents dans le fuel oil sous forme de sulfures imprégnant des particules de carbone poreux. Ces microparticules peuvent être générées lorsque l'on applique des conditions opératoires sévères à la viscoréduction de fuels résiduaires en présence d'hydrogène et d'un catalyseur approprié. Ces microparticules se sont révélées très actives en combustion et ont montré que la concentration du métal n'était pas le seul facteur à prendre en considération mais que la manière dont il était combiné pouvait être prépondérante. Pour étendre le domaine d'application des modèles, d'autres paramètres comme les conditions de fonctionnement de la chaudière et l'atomisation du fuel ont été pris en compte en plus des paramètres d'influence propres au fuel (travaux du Laboratoire Énergie du MIT publications 1986. En ce qui concerne la prédiction d'émissions particulaires une méthode complémentaire aux tests de résidu de Conradson et d'insolubilité à l'heptane normal a été appliquée à I'IFP dans le cadre d'un programme de valorisation des huiles lourdes en association avec les compagnies pétrolières Elf et Total France. Cette méthode consiste à évaluer à la microscopie électronique par transmission le taux de dispersion des asphaltènes, selon une méthode développée par Total France (M. Peyrot. Il existe une relation entre ce taux de dispersion et l'émission particulaire. Ce phénomène a été nettement observé dans le cas de fuels lourds constitués par

Multidetector system for the identification of and measurement of the energies of heavy ions at intermediate energies; Systeme multidetecteur pour l`identification et la mesure des energies des ions lourds aux energies intermediaires

Energy Technology Data Exchange (ETDEWEB)

Samri, M; Beaulieu, L; Djerroud, B [Laval Univ., Quebec City, PQ (Canada). Dept. de Physique; and others

1994-12-31

A scintillation multidetector system composed (at the present time) of 80 detectors is described and its performance reported. It contains both phoswich and CsI detectors. A number of recent publications have shown that CsI or phoswich detectors do not have an adequately quantitative response to heavy ions in the intermediate energy range, but this difficulty can be avoided by calibrating the detectors for energy. In the present case, the use of the technique of secondary detector clusters is shown to be effective. Detection over a wide solid angle is possible. 19 refs., 3 tabs., 3 figs.

Study of the pulsation of an ion accelerator giving 20 nano-second pulses; Etude de la pulsation d'un accelerateur d'ions fournissant des impulsions d'une duree de 20 nano-secondes

Energy Technology Data Exchange (ETDEWEB)

Cosnac, B de [Commissariat a l' Energie Atomique, Fontenay aux Roses (France). Centre d' Etudes Nucleaires

1965-03-01

In order to measure fast neutron spectra by the time-of-flight method, we have studied a pulsed ion-source which has been placed on the 600 kV electrostatic accelerator at Fontenay-aux-Roses. We examine successively: the ion-source itself, its extraction device, the focussing equipment and the pulsation system constituted by a slit which is swept by the beam. Using this ion-source it is possible to obtain a direct current of deutons of over 800 {mu}A, and clouds having a duration which can be adjusted to between 15 and 40 nano-seconds. (author) [French] Pour mesurer des spectres de neutrons rapides par la methode de temps de vol, nous avons etudie une source d'ions pulsee qui a ete placee sur l'accelerateur electrostatique de 600 kV de Fontenay-aux-Roses. Nous examinons successivement: la source d'ions elle-meme, son dispositif d'extraction, l'optique de focalisation et le systeme de pulsation constituee par le balayage du faisceau devant une fente. La source d'ions permet d'obtenir un courant continu de deutons superieur a 800 {mu}A et des bouffees d'une duree reglable comprise entre 15 et 40 nanosecondes. (auteur)

Absorption spectra between 0.8 {mu} and 30 {mu} of mixtures of H{sub 2}O - D{sub 2}O in the liquid state; Le spectre d'absorption des melanges H{sub 2}O-D{sub 2}O a l'etat liquide entre 0,8 et 30 {mu}

Energy Technology Data Exchange (ETDEWEB)

Ceccaldi, M; Goldman, M; Roth, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

There has been very little work carried out recently on the absorption bands of H{sub 2}O, HDO and D{sub 2}O in the liquid state. We have established the spectra of these molecules in between 0.8 and 30 p. The table of absorption bands of the molecules HDO and D{sub 2}O for which all the bands corresponding to those for H{sub 2}O had not been established has been completed. We have sought a convenient method of representing the variations in optical density of certain HDO bands as a function of the concentration of heavy water in the mixtures studied. (author) [French] Il y a peu de travaux recents sur les bandes d'absorption de H{sub 2}O, HDO et D{sub 2}O a l'etat liquide. Nous avons releve les spectres de ces molecules entre 0,8 et 30 p. Le tableau des bandes d'absorption des molecules HDO et D{sub 2}O, pour lesquelles le releve de toutes les bandes correspondantes a celles de H{sub 2}O n'etait pas encore effectue, a ete complete. Nous avons cherche des modes de representation commodes des variations de densite optique de certaines bandes de HDO en fonction de la teneur en eau lourde des melanges etudies. (auteur)

2657-IJBCS-Article-Dr Aminata Touré

African Journals Online (AJOL)

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Présence de métaux lourds et de résidus médicamenteux dans les effluents des établissements de ... L'objectif de cette étude est de quantifier les concentrations en métaux lourds et de rechercher la présence de ..... produits solubles représentent donc un danger de pollution de ..... residential, industrial, and agricultural.

Determinación de la variación de entalpía de la interacción entre el herbicida glifosato, y los iones de calcio, zinc y aluminio en solución acuosa por calorimetría isotérmica de titulación.

Directory of Open Access Journals (Sweden)

Flavio Adriano Bastos

2010-12-01

Full Text Available El glifosato [N-(fosfonometil glicina] es una molécula no selectivo ampliamente utilizado en Brasil como un desecante en los cultivos sin labranza, entre las hileras de los cultivos perennes y para la eliminación de las malezas en ambientes acuáticos. Es el herbicida más usado en el mundo. Debido a la presencia de grupos amino, carboxílico y fosfónico en su molécula, este herbicida es capaz de formar complejos con metales fuertes. El objetivo de este trabajo fue la determinación de los parámetros de la termodinámica de las interacciones entre el glifosato y el calcio, cobre, zinc y aluminio por calorimetría isotérmica de titulación (ITC. Los experimentos se llevaron a cabo a 298,15 K en una solución acuosa de pH controlado y es igual a 2,00. El tratamiento de los datos se realizó por el Método de la Tangente. Los resultados para el cambio de entalpía (kJ.mol-1, la energía libre de Gibbs (kJ.mol-1 y cambio de entropía (J.mol-1K-1, fueron, respectivamente: Ca (II = + 0,07 ± 0,01; - 18,8 ± 0,5, 63,0 ± 2; Cu (II = + 6,24 ± 0,06, - 67,9 ± 0,5, 249 ± 2; Zn (II = + 0,25 ± 0,01, - 49,7 ± 0,5, 167 ± 2 e Al (III = + 6,84 ± 0,45, - 78,2 ± 0,5, 285 ± 2. Los complejos formados son entrópicamente impulsado, desde el punto de vista energético, las interacciones se presentan muy pobres, que pueden ser observadas por los valores positivos del cambio de entalpia. Esto se debe principalmente a la eliminación de las moléculas de agua de hidratación de los iones de metal para la mayor parte de la solución. Con la información actual, podemos concluir que la complejidad del herbicida con el ion de aluminio es más fuerte que con otro cationes.

Ion-ion collisions and ion storage rings

International Nuclear Information System (INIS)

Mowat, J.R.

1988-01-01

Improved understanding of fundamental ion-ion interactions is expected to emerge from research carried out with ion storage rings. In this short survey the significant advantages and unique features that make stored ions useful targets for collision experiments are reviewed and discussed. It is pointed out that improvements to existing ion-ion experiments, as well as qualitatively new experiments, should occur over the next few years as ion storage rings become available for atomic physics. Some new experiments are suggested which are difficult if not impossible with present-day technology, but which seem feasible at storage rings facilities. (orig.)

Determinantes de la precarización laboral en Argentina entre 2003-2013: entre los cambios y las continuidades

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Marcelo Delfini

2016-03-01

Full Text Available El crecimiento económico experimentado por Argentina desde 2003 ha tenido su correlato en la mejora de los indicadores laborales. No obstante, la precarización laboral se ha mantenido, luego de una baja importante hasta el año 2007, en valores muy elevados. Partiendo de la idea central que la precarización constituye para el capital, una reducción de costos, el objetivo de este artículo es dar cuenta de los determinantes de la informalidad entre los trabajadores asalariados, estableciendo continuidades y cambios entre los años 2003 y 2013. Para ello utilizamos una metodología cuantitativa con fuentes secundarias de información, a partir de las cuales realizamos dos tipo de análisis, el primero de carácter descriptivo a partir del cual se busca dar cuenta de las características del mercado de trabajo argentino entre 1990 y 2013 y el segundo se realiza por medio de una regresión logística binomial, que permite acercarnos a los determinantes de la precarización de las condiciones de trabajo. En este sentido, se pudo observar que entre los años 2003 y 2013, se consolidó una precarización laboral, cuyos determinantes no lograron modificarse sustancialmente entre los años de referencia.

Results and interpretation of spectral indices measurements made with AQUILON; Resultats et interpretation de mesures d'indices de spectre dans aquilon

Energy Technology Data Exchange (ETDEWEB)

Frichet, J P; Mougey, J N; Naudet, R; Taste, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-07-01

This report deals with a set of spectral indices measurements made in the heavy water reactor Aquilon on lattices constituted by massive fuel elements of dia. 29,2 mm. The fuel elements were made either of natural uranium or of slightly depleted or slightly enriched uranium, or of an uranium-plutonium alloy. The measurements were carried out for various lattice pitches (square pitch from 110 to 210 mm) and in certain cases for various temperatures (from 20 to 80 deg. C). The results are compared to calculated values obtained by using the latest advances of the thermalization theory developed at Saclay applied to the moderation by heavy water. (authors) [French] Ce rapport est consacre a un ensemble de mesures d'indices de spectre realisees dans la pile a eau lourde Aquilon sur des reseaux d'elements combustibles pleins, de 29,2 mm de diametre. Ces combustibles se composaient ou bien d'uranium naturel, ou bien d'uranium tres legerement appauvri ou enrichi, ou bien d'un alliage uranium plutonium. Les mesures ont ete effectuees pour toute une serie de pas de reseaux (pas carre 110 a 210 mm), certaines d'entre elles a plusieurs temperatures (20 a 80 deg. C). Les resultats des mesures sont compares a des valeurs calculees obtenues en utilisant les plus recents developpements de la theorie de la thermalisation mise au point a Saclay, appliques au cas de la moderation par l'eau lourde. (auteurs)

1746-IJBCS-Article-Momar Ndiaye

African Journals Online (AJOL)

hp

2013 International Formulae Group. All rights reserved. Mots clés: Métaux lourds, moule, sédiment, toxicité, émission atomique. ... teneurs des métaux lourds cadmium, chrome et plomb dans les sédiments et les moules. MATERIEL ET ..... les sédiments, des éléments minéraux et organiques provenant des eaux usées, des.

Study of secondary electron emission from thin carbon targets with swift charged particles: heavy ions, hydrogen ions; Etude experimentale de l`emission electronique secondaire de cibles minces de carbone sous l`impact de projectiles rapides: ions lourds, ions hydrogene (atomiques, moleculaires ou sous forme d`agregats)

Energy Technology Data Exchange (ETDEWEB)

Billebaud, A

1995-07-12

The main subject of this work is the study of electron emission from the two surfaces of thin solid targets bombarded with swift charged particles. The slowing down of swift ions in matter is mainly due to inelastic interaction with target electrons (ionization, excitation): the energy transfer to target electrons is responsible for the secondary electron emission process. The phenomenological and theoretical descriptions of this phenomena are the subject of the first chapter. We focused on secondary electron emission induced by different kind of projectiles on thin carbon foils. In chapter two we describe hydrogen cluster induced electron emission measurement between 40 and 120 keV/proton. These projectiles, composed of several atoms, allowed us to study and highlight collective effects of the electron emission process. We extended our study of electron emission to molecular (H{sub 2}{sup +}, H{sub 3}{sup +}) and composite (H{sup -}, H{sup 0}) projectiles at higher energies (<= 2 MeV): we have designed an experimental set-up devoted to electron emission statistics measurements which allowed us to study, among others things, the role of projectile electrons in secondary electron emission. This experiment is described in the third chapter. Finally, the fourth chapter describes new measurements of electron emission induced by energetic (13 MeV/u) and highly charged argon ion provided by the medium energy beam line (SME) of GANIL (Caen), which have been analyzed in the framework of a semi-empirical model of secondary electron emission. This set of experiments brings new results on composite projectile interaction with matter, and on the consequences of high energy deposition in solids. (author).

Study of the point defect creation and of the excitonic luminescence in alkali halides irradiated by swift heavy ions; Etude de la creation de defauts ponctuels et de la luminescence excitonique d`halogenures d`alcalins irradies par les ions lourds de grande vitesse

Energy Technology Data Exchange (ETDEWEB)

Protin, L

1994-10-05

The aim of this experimental thesis is to study the excitonic mechanisms and of the defect creation, in NaCl and KBr, under dense electronic excitations induced by swift heavy ion irradiations. In the first part, we present the main features of the interaction of swift heavy ions with solid targets, and after we review the well known radiolytic processes of the defect creation during X-ray irradiation. In the second chapter, we describe our experimental set-up. In the chapter III, we present our results of the in-situ optical absorption measurements. This results show that defect creation is less sensitive to the temperature than during a classical irradiation. Besides, we observe new mechanisms concerning the defect aggregation. In the chapter IV, we present the results of excitonic luminescence induced by swift by swift heavy ions. We observe that the luminescence yields only change with the highest electronic stopping power. In the chapter V, we perform thermal spike and luminescence yields calculations and we compare the numerical results to the experiments presented in the chapter IV. (author). 121 refs., 65 figs., 30 tabs.

Relación entre esquemas inadaptativos, distorsiones cognitivas y síntomas de ludopatía en jugadores de casinos

OpenAIRE

Marly Johana Bahamón Muñetón

2013-01-01

Objetivo . Identificar las relaciones existentes entre esquemas inadaptativos, distors iones cognitivas y síntomas de ludopatía en 27 jugadores asiduos de casinos en la ciudad de Pereira. Método . Se empleó un enfoque cuantitativo con diseño correlacional, en el cual se aplicó el cuestionario de juego patológico de South Oaks (SOGS; Lesieur y Blume, 1987; validación española de Echeburúa, Báez, Fernández-Mo ntalvo y Páez, 1994), el Young Schema Questionnaire Long Form – Second edition (valida...

El periodista, entre el Poder

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JL Dader

2014-10-01

Full Text Available El periodismo se debate, desde sus orígenes, entre la reproducción servil de versiones interesadas o la distorsión de propio cuño, por conocimiento insuficiente de una realidad que sólo puede entrever. Los poderes que amenazan la independencia periodística no han hecho más que crecer o aumentar su habilidad con el paso del tiempo. Surgido como ‘oficio de esclavos’ en la época romana, muchos indicadores actuales parecen retornarle al punto de partida: relaciones públicas estratégicas a gran escala, auge de los ‘spin doctors’, extorsión descarnada en las democracias más débiles y populismo de las redes sociales, entre otros. Todo ello, unido o alentado por la degradación interna y el desaliento de la propia institución periodística incapaz de distanciarse de todas esas fuerzas. Su respuesta no puede ser de alianza o competencia con los poderes que la circundan, sino de hábil distanciamiento para moverse entre todos ellos sin dejar de ejercer la vigilancia que los ciudadanos siguen necesitando de su ejercicio profesional.

A study of the fixing of phosphoric ions by zirconium-montmorillonite; Etude de la fixation d'ions phosphoriques par la montmorillonite-zirconium

Energy Technology Data Exchange (ETDEWEB)

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

1960-07-01

In connection with the research carried out on the purification of nuclear reactor water, we have undertaken a study of the ion-exchange properties of acid montmorillonite. In a previous paper, we described the preparation of zirconium-montmorillonite small plate. The present article aims to study some of the properties of the clay obtained. We have observed that zirconium-montmorillonite fixes very strongly the phosphorus from solutions of phosphoric acid or of phosphates: on 1 g of clay it is possible to fix 1,2 milli-atoms-gram of zirconium and the zirconium montmorillonite itself fixes 2,1 milli-atoms-gram of phosphorus. An explanation of these experimental results, which is as much chemical as mineralogical, is the hypothesis that the fixing of phosphoric ions modifies the distribution of the ions between the platelets and precipitates a very slightly soluble product of the type diphospho-zirconic acid. (author) [French] En rapport avec des recherches sur I'epuration de l'eau des reacteurs nucleaires nous avons entrepris une etude sur les proprietes d'echangeur d'ions de la montmorillonite-acide. Dans une precedente publication, nous avons decrit la preparation des plaquettes de montmorillonite-zirconium. La presente communication a pour but d'etudier quelques proprietes de l'argile obtenue. Nous avons constate que la montmorilionite-zirconium fixe le phosphore de solutions d'acide phosphorique ou de phosphate avec une grande intensite: sur 1 g d'argile, on peut fixer 1,2 atomes-gramme de zirconium, et la montmorillonite-zirconium fixe a son tour 2,1 milli-atomesgramme de phosphore. Une explication des resultats experimentaux, tant d'ordre chimique que d'ordre mineralogique, consiste en l'hypothese suivant laquelle la fixation d'ions phosphoriques modifierait la repartition des ions entre les feuillets avec precipitation du compose tres peu soluble (type: acide diphosphozirconique). (auteur)

Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances

International Nuclear Information System (INIS)

Perkins, F.W.

1977-04-01

For the ion-ion hybrid resonance it is shown that: (1) the energy absorption occurs via a sequence of mode conversions; (2) a poloidal field component normal to the ion-ion hybrid mode conversion surface strongly influences the mode conversion process so that roughly equal electron and ion heating occurs in the present proton-deuterium experiments, while solely electron heating is predicted to prevail in deuterium-tritium reactors; (3) the ion-ion hybrid resonance suppresses toroidal eigenmodes; and (4) wave absorption in minority fundamental ion-cyclotron heating experiments will be dominated by ion-ion hybrid mode conversion absorption for minority concentrations exceeding roughly 1 percent. For the ion-cyclotron resonance, it is shown that: (1) ion-cyclotron mode conversion leads to surface electron heating; and (2) ion-cyclotron mode conversion absorption dominates fundamental ion-cyclotron absorption thereby preventing efficient ion heating

A phenomenon of direct conversion of ionizing energy resulting from the formation of negative droplets by electron capture during condensation of a vapour even without electronic affinity; Sur un phenomene de conversion directe d'energie ionisante resultant de la formation de gouttelettes negatives par capture d'electrons, lors de la condensation d'une vapeur, meme sans affinite electronique

Energy Technology Data Exchange (ETDEWEB)

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

1969-06-01

An electromotive force is produced between a cold and a hot electrode immersed in an ionized vapour. It is shown that the dissymmetry thus created consists in the formation of heavy, negative charge carriers following the condensation of the vapour in the volume close to the cold electrode. The electromotive forces produced are explained on the basis of a decrease in the floating potential of the cold electrode. (author) [French] Une force electromotrice apparaissant entre une electrode chaude et une electrode froide plongees dans une vapeur ionisee, on etablit que la disymetrie ainsi causee consiste en la formation de porteurs de charge negatifs lourds consecutive a la condensation de la vapeur en volume pres de l'electrode froide. On justifie les forces electromotrices observees par la diminution du potentiel flottant de l'electrode froide. (auteur)

Bases del intercambio entre las sociedades norperuanas y surecuatorianas: una zona de transición entre 1500 A.C. y 600 D.C

Directory of Open Access Journals (Sweden)

1993-01-01

Full Text Available BASES DE L'ECHANGE ENTRE LES SOCIETES NORD-PERUVIENNES ET SUD-EQUATORIENNES : UNE ZONE DE TRANSITION ENTRE 1500 AV. J.C. ET 600 AP. J.C. Cet article est le fruit d’une tentative de coopération entre des chercheurs qui travaillent en Équateur et au Pérou, pour relier les deux aires culturelles nettement différenciées, nord-andine et centre-andine, à partir de la définition et de l’étude d’une zone de transition, localisée entre le Río Jubones dans le sud de l'Équateur et le Río Olmos dans le nord du Pérou, entre environ 1500 av. J.C. et 600 ap. J.C. El artículo es resultado de un intento de cooperación entre investigadores que trabajan el Ecuador y el Perú para vincular las dos áreas culturales marcadamente diferenciadas, norandina y centroandina, a partir de la definición y estudio de una zona de transición, localizada entre el río Jubones, al sur de Ecuador y el Río Olmos, al norte de Perú, entre aproximadamente 1500 AC y 600 DC. BASIS OF THE EXCHANGE BETWEEN NORTH PERUVIAN AND SOUTH ECUATORIAN SOCIETIES: A TRANSITIONAL ZONE BETWEEN 1500 B.C. AND 600 A.C. This paper is a collaborative effort by researchers working in Ecuador and Peru, to explore the relationship between two clearly differentiated cultural areas (North and Central Andes on the basis of a definition and study of the prehistory transitional zone located between Río Jubones in Southern Ecuador and Río Olmos in Northern Peru between 1500 B.C. and 600 A.C.

Ion-specific thermodynamical properties of aqueous proteins

Directory of Open Access Journals (Sweden)

Eduardo R.A. Lima

2010-03-01

Full Text Available Ion-specific interactions between two colloidal particles are calculated using a modified Poisson-Boltzmann (PBequationandMonteCarlo(MCsimulations. PBequationspresentgoodresultsofionicconcentration profiles around a macroion, especially for salt solutions containing monovalent ions. These equations include not only electrostatic interactions, but also dispersion potentials originated from polarizabilities of ions and proteins. This enables us to predict ion-specific properties of colloidal systems. We compared results obtained from the modified PB equation with those from MC simulations and integral equations. Phase diagrams and osmotic second virial coefficients are also presented for different salt solutions at different pH and ionic strengths, in agreement with the experimental results observed Hofmeister effects. In order to include the water structure and hydration effect, we have used an effective interaction obtained from molecular dynamics of each ion and a hydrophobic surface combined with PB equation. The method has been proved to be efficient and suitable for describing phenomena where the water structure close to the interface plays an essential role. Important thermodynamic properties related to protein aggregation, essential in biotechnology and pharmaceutical industries, can be obtained from the method shown here.Interações íon-específicas (dependentes do tipo de íon presente em solução entre duas partículas coloidais são calculadas usando a equação de Poisson-Boltzmann (PB modificada e simulações de Monte Carlo (MC. As equações de PB apresentam bons resultados de perfis de concentração nas proximidades de um macro-íon, principalmente para soluções salinas contendo íons monovalentes. Estas equações incluem não só interações eletrostáticas, mas também potenciais de dispersão, que têm origem nas polarizabilidades de íons e proteínas, permitindo a predição de propriedades íon-específicas de

Heavy Element Staining of Sedimentary Organic Matter Functional Groups for Backscattered Electron Imaging Marquage par éléments lourds de la matière organique sédimentaire pour la microscopie électronique en électrons rétrodiffusés

Directory of Open Access Journals (Sweden)

Belin-Geindre S.

2006-11-01

, 1992. Son imagerie est basée sur les contrastes de numéro atomique (Z existant entre les divers constituants. La matière organique apparaît noire et les minéraux gris. Cependant il n'est pas possible de distinguer plusieurs types de matière organique avec le MEB/ER. Afin de mettre en évidence des contrastes au MEB/ER entre différentes matières organiques, les échantillons ont été marqués par des éléments lourds qui ont la particularité de se fixer de manière sélective et spécifique sur les groupes fonctionnels. Cette méthode est largement employée par la biologie cellulaire pour révéler divers corps organiques (Soligo et Lambertenghi-Deliliers, 1987; Langsdorff et al. , 1990; Clark, 1991; Namimatsu, 1992 ou bien par la science des matériaux dans le domaine des polymères (Sawyer et Grubb, 1987; Ohlsson et Törnell, 1990; Sue et al. , 1991; Janik et al. , 1992. L'application à la géologie et à la pétrographie est restée jusqu'à présent assez réduite : sédiments argileux (Whitlatch et Johnson, 1974; Green et al. , 1979; Bishop et al. , 1992; Hillier et Clayton, 1992, charbons (Corcoran et Stephens, 1987; Sommerfeld et al. , 1992, sols (Foster, 1981. Les éléments lourds utilisés pour le marquage sont très variés et présentent une spécificité plus ou moins large (Reynolds, 1963; Lewis et Knight, 1976; Takeuchi et Takeuchi, 1990. La matière organique sédimentaire est un mélange complexe de macromolécules dont la composition dépend de la nature de la matière organique originelle et de son degré d'évolution (Tissot et Welte, 1984. La matière organique peu évoluée possède de nombreuses variétés de groupes fonctionnels (Rouxhet et al. , 1980; Béhar et Vandenbroucke, 1987. La faisabilité de la méthode a d'abord été testée sur des polymères contenant des fonctions chimiques susceptibles d'exister dans les kérogènes naturels (tableau 1. Puis elle a été appliquée à des sédiments presque exclusivement formés de

Contribution à l'étude de l'immobilisation des ions plomb en solution ...

African Journals Online (AJOL)

DK

The aim of this work is to study to the fixation of lead ions (Pb2+) in aqueous solution by adsorption on natural phosphate (NP). Batch tests were conducted to ... entraîné la détérioration de la qualité de l'eau, de l'air et du sol. Les eaux naturelles sont .... L-1, le pH du mélange est ajusté entre 5 et 6. La solution est agitée à.

Study of the behaviour of some heavy elements in solvents containing hydrogen fluoride; Etude du comportement de quelques elements lourds dans des solvants a base d'acide fluorhydrique

Energy Technology Data Exchange (ETDEWEB)

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

1967-01-01

The anhydrous liquid mixtures: dinitrogen tetroxide-hydrogen fluoride and antimony pentafluoride-hydrogen fluoride were studied as solvents for heavy elements interesting nuclear energy: uranium, thorium, zirconium and for some of their compounds. For N{sub 2}O{sub 4}-HF mixtures, electric conductivity measurements and liquid phase infrared spectra were also obtained. Uranium and zirconium tetrafluoride are much more soluble in N{sub 2}O{sub 4}-HF mixtures than in pure hydrogen fluoride. Uranium dissolved in these mixtures is pentavalent. In SbF{sub 5}-HF mixtures, uranium dissolves with hydrogen evolution and becomes trivalent. The solid compound resulting from the dissolution is a fluoro-antimonate: U(SbF{sub 6}){sub 3}. (author) [French] On a etudie les melanges liquides anhydres: peroxyde d'azote-acide fluorhydrique et pentafluorure d'antimoine-acide fluorhydrique comme solvants d'elements lourds interessant l'energie nucleaire: uranium, thorium, zirconium et de quelques uns de leurs composes. Pour les melanges N{sub 2}O{sub 4}-HF on a egalement effectue des mesures de conductivite electrique, ainsi que des spectres d'absorption infrarouge en phase liquide. Le tetrafluorure d'uranium et le tetrafluorure de zirconium sont beaucoup plus solubles dans les melanges N{sub 2}O{sub 4}-HF que dans l'acide fluorhydrique. L'uranium dissous dans ces melanges est a l'etat pentavalent. Dans les melanges SbF{sub 5}-HF l'uranium se dissout avec degagement d'hydrogene et passe a l'etat trivalent. Le compose solide resultant de la dissolution est un fluoantimoniate: U(SbF{sub 6}){sub 3}. (auteur)

2140-IJBCS-Article-Koffi Marcelin Yao

African Journals Online (AJOL)

hp

Mots clés : Métaux traces, matière organique, adsorption, désorption, Estuaire. INTRODUCTION. La contamination de l'atmosphère, de l'hydrosphère et des sédiments par les métaux lourds est aujourd'hui très préoccupant pour les pays développés et émergents. Les métaux lourds sont des éléments métalliques dont la.

Calculation of ion storage in electron beams with account of ion-ion interactions

International Nuclear Information System (INIS)

Perel'shtejn, Eh.A.; Shirkov, G.D.

1979-01-01

Ion storage in relativistic electron beams was calculated taking account of ion-ion charge exchange and ionization. The calculations were made for nitrogen ion storage from residual gas during the compression of electron rings in the adhezator of the JINR heavy ion accelerator. The calculations were made for rings of various parameters and for various pressures of the residual gas. The results are compared with analogous calculations made without account of ion-ion processes. It is shown that at heavy loading of a ring by ions ion-ion collisions play a significant part, and they should be taken into account while calculating ion storage

Statistical and off-equilibrium production of fragments in heavy ion collisions at intermediate energies; Production statistique et hors-equilibre de fragments dans les collisions d`ions lourdes aux energies intermediaires

Energy Technology Data Exchange (ETDEWEB)

Bocage, Frederic [Lab. de Physique Corpusculaire, Caen Univ., 14 - Caen (France)

1998-12-15

The study of reaction products, fragments and light charged particles, emitted during heavy-ion collisions at intermediate energies has shown the dominant binary dissipative character of the reaction, which is persisting for almost all impact parameters. However, in comparison with this purely binary process, an excess of nuclear matter is observed in-between the quasi-projectile and the quasi-target. To understand the mechanisms producing such an excess, this work studies more precisely the breakup in two fragments of the quasi-projectile formed in Xe+Sn, from 25 to 50 MeV/u, and Gd+C and Gd+U at 36 MeV/u. The data were obtained during the first INDRA experiment at GANIL. The angular distributions of the two fragments show the competition between statistical fission and non-equilibrated breakup of the quasi-projectile. In the second case, the two fragments are aligned along the separation axis of the two primary partners. The comparison of the fission directions and probabilities with statistical models allows us to measure the fission time, as well as the angular momentum, temperature and size of the fissioning residue. The relative velocities are compatible with Coulomb and thermal effects in the case of statistical fission and are found much higher for the breakup of a non-equilibrated quasi-projectile, which indicates that the projectile was deformed during interaction with the target. Such deformations should be compared with dynamical calculations in order to constrain the viscosity of nuclear matter and the parameters of the nucleon-nucleon interaction, (author) 148 refs., 77 figs., 11 tabs.

USO DE TABACO ENTRE ADOLESCENTES: REVISÃO DE LITERATURA

OpenAIRE

Amanda Márcia dos Santos Reinaldo; Camila Cesar Goecking; Jennifer Perucci de Almeida; Yasmin Narciso Goulart

2010-01-01

Revisión sistemática de la literatura sobre el uso de tabaco entre adolescentes. La utilización del tabaco entre adolescentes, en general, puede estar asociada al éxito, a la necesidad de aceptación, a cuestiones familiares, entre otros factores que incentivan de cierta forma a su uso. Las políticas de salud para el área trabajan para prevenir y reducir el consumo, alertando en relación al riesgo al que tal población se expone cuando utiliza tabaco. Conocer el perfil de los adolescentes que u...

Ion-Ion Plasmas Produced by Electron Beams

Science.gov (United States)

Fernsler, R. F.; Leonhardt, D.; Walton, S. G.; Meger, R. A.

2001-10-01

The ability of plasmas to etch deep, small-scale features in materials is limited by localized charging of the features. The features charge because of the difference in electron and ion anisotropy, and thus one solution now being explored is to use ion-ion plasmas in place of electron-ion plasmas. Ion-ion plasmas are effectively electron-free and consist mainly of positive and negative ions. Since the two ion species behave similarly, localized charging is largely eliminated. However, the only way to produce ion-ion plasmas at low gas pressure is to convert electrons into negative ions through two-body attachment to neutrals. While the electron attachment rate is large at low electron temperatures (Te < 1 eV) in many of the halogen gases used for processing, these temperatures occur in most reactors only during the afterglow when the heating fields are turned off and the plasma is decaying. By contrast, Te is low nearly all the time in plasmas produced by electron beams, and therefore electron beams can potentially produce ion-ion plasmas continuously. The theory of ion-ion plasmas formed by pulsed electron beams is examined in this talk and compared with experimental results presented elsewhere [1]. Some general limitations of ion-ion plasmas, including relatively low flux levels, are discussed as well. [1] See the presentation by D. Leonhardt et al. at this conference.

Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect; Etude de la pulverisation du dioxyde d'uranium induite par des ions lourds multicharges de basse et tres basse energie cinetique; effet de la charge du projectile

Energy Technology Data Exchange (ETDEWEB)

Haranger, F

2003-12-01

Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

Relação entre ansiedade, depressão e desesperança entre grupos de idosos Relación entre ansiedad, depresión y desesperanza entre grupos de ancianos Relations between anxiety, depression and hopelessness among elderly groups

Directory of Open Access Journals (Sweden)

Katya Luciane de Oliveira

2006-08-01

Full Text Available O envelhecimento é uma etapa da vida que permanece pouco conhecida e estudada, se comparada a outras fases do desenvolvimento humano. Nesta pesquisa buscou-se explorar a relação entre ansiedade, depressão e desesperança entre grupos de idosos. Participaram deste estudo 79 idosos provenientes de centro do terceira idade de um posto de retirada de medicamentos e de uma instituição asilar. Utilizou-se um questionário para os dados de caracterização dos idosos, bem como as escalas Beck para mensurar sintomas de ansiedade, depressão e desesperança. Os resultados evidenciaram relação estatisticamente significativa entre ansiedade, depressão e desesperança nos idosos. O grupo de asilares apresentou uma maior incidência de sintomas ansiosos, depressivos e desesperançosos em relação aos outros dois grupos.El envejecimiento es una etapa de la vida que permanece poco conocida o estudiada, al ser comparada a otras fases del desarrollo humano. Esta investigación buscó explorar la relación entre ansiedad, depresión y desesperanza entre grupos de ancianos. Participaron en este estudio 79 adultos mayores provenientes de tres sitios diferentes: un centro de tercera edad, un puesto de retirada de medicinas y un asilo. Un cuestionario para los datos de caracterización de los ancianos fue utilizado, así como las escalas Beck para mensurar síntomas de ansiedad, depresión y desesperanza. Los resultados dejaron en evidencia relación estadísticamente significativa entre dichos síntomas en los adultos mayores. El grupo proveniente del asilo presentó mayor incidencia de manifestaciones en relación con los demás grupos.Aging is a life stage that remains hardly ever studied and, consequently, unknown if compared to other human development phases. This research investigates the relation between anxiety, depression and hopelessness among elderly groups. 79 elderly people, from three different units, such as a 'third-age-center', a center of

Decay properties of exotic N ≅ 28 S and Cl nuclei and the 48Ca/46Ca abundance ratio

International Nuclear Information System (INIS)

Sorlin, O.; Guillemaud-Mueller, D.; Mueller, A.C.; Borrel, V.; Dogny, S.; Pougheon, F.; Anne, R.; Lewitowicz, M.; Saint-Laurent, M.G.; Borcea, C.; Fifield, L.K.; Bazin, D.; Thielemann, F.K.; Hillebrandt, W.

1992-01-01

Beta-decay half-lives and β-delayed neutron-emission probabilities of the very neutron-rich nuclei 44 S and 45-47 Cl have been measured. These isotopes, which lie at or close to the N=28 magic shell were produced in interactions of a 60 MeV/u 48 Ca beam from GANIL (Grand Accelerateur National d'Ions Lourds) with a 64 Ni target and were separated by the doubly achromatic spectrometer LISE (Ligne d'Ions Super Epluches). Their decay was studied by a β-n time correlation measurement. The results are compared to recent model predictions and indicate a rapid weakening of the N=28 shell effect below 48 20 Ca 28 . The nuclear structure effects reflected in the decay properties of the exotic S and Cl isotopes may be the clue for the astrophysical understanding of the unusual 48 Ca/ 46 Ca abundance ratio measured in the solar system as well as the Ca-Ti-Cr anomalies observed in EK-inclusions of the Allende meteorite

Floridablanca entre la modernidad y la posmodernidad

OpenAIRE

Senatore, María Ximena

2007-01-01

Este artículo se centra en los diálogos entre el pasado y el presente creados en el marco de la modernidad y de la posmodernidad. La arqueología como práctica social puede ser entendida como un diálogo pasado-presente. Floridablanca es una historia, un sitio, una experiencia, una idea, una utopía. Es también un punto de encuentro entre modernidad y posmodernidad. El objetivo de este trabajo es presentar ciertas reflexiones sobre los diálogos pasado-presente que crean, transforman y reproducen...

827-IJBCS-Article-Elisabeth Yehouenou

African Journals Online (AJOL)

DR GATSING

La zone nord est surélevée par rapport à la zone sud. Taux de métaux lourds dans le sol. La Figure 1 montre la teneur en métaux lourds dans les échantillons de sols prélevés aussi bien du côté sud que du côté nord du site. Il en ressort que lesdits sols sont contaminés par des métaux toxiques comme le zinc, le chrome, le ...

Majority ion heating near the ion-ion hybrid layer in tokamaks

International Nuclear Information System (INIS)

Phillips, C.K.; Hosea, J.C.; Ignat, D.; Majeski, R.; Rogers, J.H.; Schilling, G.; Wilson, J.R.

1995-08-01

Efficient direct majority ion heating in a deuterium-tritium (D-T) reactor-grade plasma via absorption of fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) is discussed. Majority ion heating results from resonance overlap between the cyclotron layers and the D-T ion-ion hybrid layer in hot, dense plasmas for fast waves launched with high parallel wavenumbers. Analytic and numerical models are used to explore the regime in ITER plasmas

Production of an intense source of micro-second proton pulses; Recherche d'une intense source de protons pulsee a la micro-seconde

Energy Technology Data Exchange (ETDEWEB)

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

1965-02-01

In order to obtain micro-second proton pulses of 100 mA, we have built a duoplasmatron ion source and beam focusing equipment. The pulses of the ion-source were produced by a load discharge. The source operates as a hydrogen-thyratron. The particular geometry of the duoplasmatron was chosen in order that the ion emission be stable with a 10 A arc and with a gas-flow lower than 10 cm{sup 3}/h T.P.N. Studies of the beam showed preponderance of protons and the presence of heavy ions. The beam density is higher on the optic axis. (author) [French] Pour obtenir des impulsions d'une microseconde de 100 mA de protons, on a ete amene a construire une source 'duoplasmatron' et son optique de focalisation. La pulsation de la source a ete faite par decharge d'une ligne, la source fonctionnant elle-meme comme un thyratron a hydrogene. La geometrie de la source a ete etudiee pour que l'emission d'ions soit stable avec un arc de 10 amperes de crete et un debit de gaz de 10 cm{sup 3}/h T.P.N. Une analyse du faisceau a revele la preponderance des protons et l'existence d'ions lourds. La densite du faisceau est plus grande sur l'axe de l'optique.

DIVERSIDAD GENÉTICA ENTRE SUBPOBLACIONES RACIALES BOVINAS DE COSTA RICA

Directory of Open Access Journals (Sweden)

Marco Martínez

2015-01-01

Full Text Available El objetivo del estudio fue cuantificar la diversidad genética entre 16 subpoblaciones raciales bovinas de Costa Rica, con base en 1412 muestras de ADN bovino de todo el país, evaluadas mediante 18 marcadores microsatélites. El número promedio de alelos (Na por locus dentro de raza fue de 10,3, que varían entre 8 (Holstein×Jersey y 13 (Criolla para doble propósito. El número promedio de alelos efectivo (Ne fue de 5,04, con cambios entre 4,18 (Jersey y 5,64 (Bos taurus×Bos indicus. La heterocigosidad observada promedio fue de 0,77, variando entre 0,73 (Jersey y 0,81 (Bos taurus×Bos indicus. La heterocigosidad esperada (He promedio fue de 0,78, que oscilan entre 0,74 (Jersey y Holstein×Jersey y 0,81 (Bos taurus×Bos indicus, Criolla para doble propósito y Cruces para doble propósito. El contenido de información polimórfica (PIC fue de 0,76, con variaciones entre 0,71 (Jersey y Holstein×Jersey y 0,79 (Criollas para doble propósito y Cruces para doble propósito. El FIS promedio fue de 0,02, con oscilaciones entre -0,03 (Holstein×Jersey a 0,04 (Brahman, Criolla para carne y Cruces para leche. La desviación del equilibrio Hardy Weinberg no fue significativa (p>0,05 en la mayoría de los loci para las subpoblaciones raciales. El subgrupo con mayor número de loci en desequilibrio fue Jersey (8 loci, mientras que los subgrupos Bos taurus×Bos indicus, Criolla para leche y Holstein×Jersey presentaron solo 1 locus en desequilibrio. Los índices de fijación FIS (0,02, FIT (0,05 y FST (0,03 indicaron cierta tendencia hacia la homocigosidad. Los dendrogramas mostraron 3 agrupaciones raciales claramente diferenciadas que coinciden con las razas de origen Bos taurus, Bos indicus y sus respectivos cruces. Los resultados del análisis indicaron que el número de microsatélites empleados sí permitió establecer una discriminación clara a nivel de las frecuencias alélicas y en la distribución del tamaño de los alelos entre las

Relación entre el consumo de drogas y maltrato infantil entre estudiantes universitarios de la universidad en Colombia

Directory of Open Access Journals (Sweden)

Monica Rosaura Garcia Baquero

2015-01-01

Full Text Available Esta investigación examina la relación entre el uso de drogas en estudiantes de una Universidad Pública en Villavicencio, Colombia, y su relación con el maltrato durante la niñez, utilizando como referente teórico la perspectiva bioecológica. Estudio exploratorio retrospectivo, con una muestra de 313 estudiantes de pregrado. El 10.2% de los encuestados refiere haber sido maltratado en la Infancia y la violencia de mayor uso fue la violencia física seguida de la violencia psicológica. El 56.9% de las estudiantes encuestados han consumido sustancias psicoactivas en algún momento de la vida, y su inicio entre los 13 y los 18 años. Se evidencia maltrato en la infancia con manifestaciones de agresiones físicas, al igual que el consumo de sustancias psicoactivas, pero no se observa una relación estadísticamente significativa entre maltrato durante la infancia y el consumo de sustancias psicoactivas en la muestra estudiada.

Entre Madres: Talleres de Comunicación

OpenAIRE

Cardoso Moreno, María Jesús; Aragonés, Lucía Tomás

2015-01-01

En el presente artículo se expone el trabajo de investigación cuyo objetivo fue conocer el grado de satisfacción de las madres con un taller de formación denominado "Entremadres". Las 150 mujeres madres que participaron en el taller en la ciudad de Zaragoza, España, se conformaron en un grupo de 7 u 8 madres y estuvo compuesto por seis sesiones de dos horas cada una, entre los años 2008 y 2013. Este taller fue dirigido a madres con hijos de edades comprendidas entre 2 y 16 años. La frecuencia...

Diálogo entre el islamismo y occidente

Directory of Open Access Journals (Sweden)

Ana María MARTÍN GÓMEZ

2011-05-01

Full Text Available Este artículo analiza uno de los fenómenos más actuales de nuestras sociedades pluralistas y multiculturales: el encuentro entre la civilización occidental y la islámica. La elaboración de esta nota crítica se ha llevado a cabo tras la lectura de tres libros fundamentales acerca de esta temática: Un paseo por el laberinto. Sobre política y religión en el diálogo entre civilizaciones, de José María García Gómez-Heras, Laicismo, agnosticismo y fundamentalismo de Antonio García-Santesmases, y El islamismo contra el Islam. Las claves para entender el terrorismo yihadista, de Gustavo de Arístegui. A partir de estos tres ensayos, se ha emprendido un estudio filosófico de la situación actual entre el islamismo y Occidente.

An RF ion source based primary ion gun for secondary ion mass spectroscopy

International Nuclear Information System (INIS)

Menon, Ranjini; Nabhiraj, P.Y.; Bhandari, R.K.

2011-01-01

In this article we present the design, development and characterization of an RF plasma based ion gun as a primary ion gun for SIMS application. RF ion sources, in particular Inductively Coupled Plasma (ICP) ion sources are superior compared to LMIS and duoplasmtron ion sources since they are filamentless, can produce ions of gaseous elements. At the same time, ICP ion sources offer high angular current density which is an important factor in producing high current in small spot size on the target. These high current microprobes improve the signal to noise ratio by three orders as compared to low current ion sources such as LMIS. In addition, the high current microprobes have higher surface and depth profiling speeds. In this article we describe a simple ion source in its very basic form, two lens optical column and characteristics of microprobe

Ion mixing and numerical simulation of different ions produced in the ECR ion source

International Nuclear Information System (INIS)

Shirkov, G.D.

1996-01-01

This paper is to continue theoretical investigations and numerical simulations in the physics of ECR ion sources within the CERN program on heavy ion acceleration. The gas (ion) mixing effect in ECR sources is considered here. It is shown that the addition of light ions to the ECR plasma has three different mechanisms to improve highly charged ion production: the increase of confinement time and charge state of highly ions as the result of ion cooling; the concentration of highly charged ions in the central region of the source with high energy and density of electrons; the increase of electron production rate and density of plasma. The numerical simulations of lead ion production in the mixture with different light ions and different heavy and intermediate ions in the mixture with oxygen, are carried out to predict the principal ECR source possibilities for LHC applications. 18 refs., 23 refs

Remodelación, Transformación y Rehabilitación. Tres formas de intervenir en la Vivienda Social del siglo XX

Directory of Open Access Journals (Sweden)

Cervero Sánchez, N.

2015-03-01

Full Text Available Social housing built in Spain between 1939 and 1976 constitutes a widespread urban pattern in contemporary cities. Its initial conditions, along with the effects of time, have led to obsolescence, requiring refurbishment for revitalisation. Programs developed over the last few years not only have provided the buildings with the appropriate standards of living conditions, but also have articulated them as a whole, integrating them into the socio-economic configuration of their urban area. The evolution of these intervention models will be reviewed analyzing the Urban Remodeling of Orcasitas (Madrid and Viviendas del Gobernador housing (Barcelona, the Urban Transformation of La Mina (Barcelona and the Integral Renovation of Barrio de Lourdes (Tudela.La vivienda social construida en España entre 1939 y 1976 supone un patrón urbano extendido en la ciudad contemporánea. Sus condiciones de partida y el efecto del tiempo la han llevado a desarrollar una serie de obsolescencias, que hacen necesario intervenir para conseguir su revitalización. Los programas desarrollados en los últimos años se ocupan de dotar a las edificaciones de unos niveles de habitabilidad adecuados, pero también de su articulación como grupo, y de su integración en la distribución socioeconómica del núcleo urbano. Mediante el análisis de la Remodelación Urbana de Orcasitas (Madrid y de las Viviendas del Gobernador (Barcelona, la Transformación Urbana de La Mina (Barcelona y la Rehabilitación Integral del Barrio de Lourdes (Tudela se estudiará la evolución de estos modelos de actuación.

Recoil ion spectroscopy with heavy ions

International Nuclear Information System (INIS)

Beyer, H.F.; Mann, R.

1984-01-01

This chapter examines the production of very high charge state ions in single ion-atom collisions. Topics considered include some aspects of highly ionized atoms, experimental approaches, the production of highly charged target ions (monoatomic targets, recoil energy distribution, molecular fragmentation, outer-shell rearrangement, lifetime measurements, a comparison of projectile-, target-, and plasma-ion stripping), and secondary collision experiments (selective electron capture, potential applications). The heavy-ion beams for the described experiments were provided by accelerators such as tandem Van de Graaff facility and the UNILAC

Surface negative ion production in ion sources

International Nuclear Information System (INIS)

Belchenko, Y.

1993-01-01

Negative ion sources and the mechanisms for negative ion production are reviewed. Several classes of sources with surface origin of negative ions are examined in detail: surface-plasma sources where ion production occurs on the electrode in contact with the plasma, and ''pure surface'' sources where ion production occurs due to conversion or desorption processes. Negative ion production by backscattering, impact desorption, and electron- and photo-stimulated desorption are discussed. The experimental efficiencies of intense surface negative ion production realized on electrodes contacted with hydrogen-cesium or pure hydrogen gas-discharge plasma are compared. Recent modifications of surface-plasma sources developed for accelerator and fusion applications are reviewed in detail

“Entre propietarios y migrantes: los encuentros y desencuentros entre Colonos y Aguarunas en el alto mayo”

Directory of Open Access Journals (Sweden)

Kenneth E. Garces Montes

2013-10-01

Full Text Available La dinámica de conflictos entre colonos y nativos en el Alto Mayo, ha dado como producto continuosenfrentamientos entre caseríos de colonos y comunidades nativas colindantes, así como una seriede procesos judiciales por “usurpación de tierras”, en los cuales no se logra una ejecución efectiva dela sentencia a pesar que esta sea favorable a los nativos, debido a la distancia social que existe entrelos operadores estatales y el conflicto real. Por su parte los mecanismos de convivencia entre colonosy nativos se inician mediante el alquiler de tierras, diseñada como una fórmula temporal para quelos colonos se retiren una vez vencido el plazo del alquiler, sin embargo la ampliación de los plazosprovoca que los mismos adquieran vocación de permanencia.Una serie de actores, de primer, segundo y tercer orden interactúan alrededor de las dos dinámicasde relacionamiento mencionadas; tales como las ONGs, el Estado, organizaciones indígenas, einclusive mafias de traficantes de tierras. Ante esta realidad tan compleja conviene hacer el ejerciciode plantear propuestas de adaptabilidad (o subsistencia de las comunidades nativas, en las quese visualice la supervivencia de lo local frente a lo global en lo que a demarcación de tierras de lascomunidades nativas se refiere.

Ion-ion collisions

International Nuclear Information System (INIS)

Salzborn, Erhard; Melchert, Frank

2000-01-01

Collisions between ions belong to the elementary processes occurring in all types of plasmas. In this article we give a short overview about collisions involving one-electron systems. For collisions involving multiply-charged ions we limit the discussion to one specific quasi-one-electron system. (author)

Nexos estratégicos entre la retórica y la publicidad

Directory of Open Access Journals (Sweden)

Luis Gallardo Vera

2011-06-01

Full Text Available El presente artículo contribuye a establecer nexos estratégicos entre la retórica y la publicidad. La adopción del prisma estratégico en los estudios retóricos de la publicidad no es común, sin embargo, la relación entre retórica y publicidad a un nivel estratégico es evidente, teniendo presente los estudios que han investigado la simbiosis entre las dos actividades.Del universo compuesto por las investigaciones sobre retórica y publicidad se seleccionó una muestra de las obras susceptibles de responder a la pregunta de cuáles son los nexos estratégicos entre la retórica y la publicidad. Con este criterio se conformó una muestra teóricamente conducida del universo. La hipótesis de partida ha sido que, si existen documentos que indaguen en la relación entre la retórica y la publicidad, es posible construir un documento que muestre de un modo amplio cuáles son los nexos estratégicos entre ambas actividades. Finalmente, se contrastó que, efectivamente, este documento es único al mostrar ampliamente cuáles son los nexos estratégicos existentes entre la retórica y la publicidad.

Numerical simulation of ion temperature gradient driven modes in the presence of ion-ion collisions

International Nuclear Information System (INIS)

Xu, X.Q.

1990-08-01

Ion temperature gradient driven modes in the presence of ion-ion collisions in a toroidal geometry with trapped ions have been studied by using a 1 2/2 d linearized gyro-kinetic particle simulation code in the electrostatic limit. The purpose of the investigation is to try to understand the physics of flat density discharges, in order to test the marginal stability hypothesis. Results giving threshold conditions of L Ti /R 0 , an upper bound on k χ , and linear growth rates and mode frequencies over all wavelengths for the collisionless ion temperature gradient driven modes are obtained. The behavior of ion temperature gradient driven instabilities in the transition from slab to toroidal geometry, with trapped ions, is shown. A Monte Carlo scheme for the inclusion of ion-ion collisions, in which ions can undergo Coulomb collisional dynamical friction, velocity space diffusion and random walk of guiding centers, has been constructed. The effects of ion-ion collisions on the long wave length limit of the ion modes is discussed. 44 refs., 12 figs

About the problem of the delays between particles belonging to the cosmic radiation; Sur le probleme des retards entre des particules appartenant au rayonnement cosmique

Energy Technology Data Exchange (ETDEWEB)

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

1953-07-01

retard qui s'etablit entre deux particules de masse M appartenant a cette derniere espece est defini par la difference entre les temps qu'elles mettent pour franchir la meme distance. Dans le vide, les retards peuvent atteindre des valeurs quelconques, Mais, lorsque les particules se propagent dans un milieu absorbant, les retards tendent vers une limite bien definie quelles que soient les energies initiales des particules. On demontre que le retard maximum est donne par ({delta}t){sub max} {approx_equal} 0,6 E{sub 0} / cK{sub min}, ou E{sub 0} = Mc{sup 2} represente l'energie au repos de la particule et K{sub min} la perte minimum d'energie par cm de parcours dans le milieu donne. Par exemple, dans le cas des protons traversant differents milieux absorbants, les valeurs de ({delta}t){sub max} pour l'air (TPN), l'eau, l'Al et le Pb sont respectivement egales a 8,3.10{sup -6}, 9,7.10{sup -9}, 45.10{sup -9} et 1,6 10{sup -9} sec. Les valeurs correspondantes de ({delta}t){sub max} pour les electrons, sont de l'ordre de 10{sup -9} sec pour l'air et de l'ordre de 10{sup -12} sec pour les milieux condenses. Il en resulte que, si les particules appartenant a une gerbe manifestaient entre elles des retards superieurs a ceux qui vienent d'etre indiques, le fait constituerait une preuve suffisante de l'existence de particules lourdes au sein de la gerbe. Par ailleurs, la relation qui relie ({delta}t){sub max} a la masse M pourrait servir de base a une methode de spectrographie de masse des particules de grande energie. (auteur)

Óxidos de estaño: nuevos anodos para baterías de Ion-Litio

OpenAIRE

Morales Palomino, Julián; Sánchez, L.

1999-01-01

La reacci n entre el litio y xidos aleaciones de esta o es reversible cuando se realiza por m todos electroqu micos y a bajos potenciales con respecto al electrodo de litio. Esta propiedad permite el uso de estos materiales como electrodos negativos en el dise o y construcci n de bater as tipo ion-litio. En el caso de xidos de esta o la reacci n de inserci n de litio en la matriz conduce a la formaci n de aleaciones Li-Sn. La presencia de agregados grandes de tomos de esta o, fo...

Contribution to the study of a method for measuring continuously the isotopic effect. The search for an isotopic effect during the reduction of cuprous oxide by a {sup 12}CO - {sup 14}CO mixture (1962); Contribution a l'etude d'une methode de mesure continue de l'effet isotopique. Recherche d'un effet isotopique dans la reduction de l'oxyde cuivreux par le melange {sup 12}CO - {sup 14}CO (1962)

Energy Technology Data Exchange (ETDEWEB)

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

1961-07-15

The determination of an isotopic effect between the two reactions: {sup 12}CO + Cu{sub 2}O {yields} {sup 12}CO{sub 2} + 2 Cu 'light' reaction {sup 14}CO + Cu{sub 2}O {yields} {sup 14}C{sub O}2 + 2 Cu 'heavy' reaction is possible if the respective kinetics are known. The condensation, during the reaction, of the carbon dioxide formed, and the measurement as a function of time of the residual carbon monoxide pressure, makes it possible to deduce, uninterruptedly, the 'light' reaction kinetics. The 'heavy' reaction kinetics are obtained by measuring continuously, in situ, the radioactivity of the residual reactant gas as a function of the time. The apparatus used for this is a plastic scintillator counter. A calibration curve of the measured radioactivity as a function of the reactant gas pressure in the absence of reaction makes it possible to compare the kinetics of the 'light' and 'heavy' reactions. The reaction temperature is chosen such that the reaction rate is sufficiently slow, so that the variation of the radioactivity during unit counting time is negligible. (author) [French] La determination d'un effet isotopique entre les deux reactions: {sup 12}CO + Cu{sub 2}O {yields} {sup 12}CO{sub 2} + 2 Cu reaction 'legere' {sup 14}CO + Cu{sub 2}O {yields} {sup 14}C{sub O}2 + 2 Cu reaction 'lourde' est rendue possible par la connaissance de leurs cinetiques respectives. La condensation, au cours de la reaction, du gaz carbonique forme et la mesure en fonction du temps de la pression de l'oxyde de carbone residuel, permet d'obtenir, de facon continue, la cinetique de la reaction 'legere'. La cinetique de la reaction lourde est determinee par la mesure continue, in situ, du taux de radioactivite du reactif gazeux residuel en fonction du temps. Le dispositif employe dans ce but est un compteur a scintillateur plastique. Une courbe d'etalonnage, du taux mesure de radioactivite en fonction de la pression du gaz reactif, en l'absence de reaction, permet de comparer les

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

Energy Technology Data Exchange (ETDEWEB)

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

1955-07-01

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

Scanning ion microscopy with low energy lithium ions

International Nuclear Information System (INIS)

Twedt, Kevin A.; Chen, Lei; McClelland, Jabez J.

2014-01-01

Using an ion source based on photoionization of laser-cooled lithium atoms, we have developed a scanning ion microscope with probe sizes of a few tens of nanometers and beam energies from 500 eV to 5 keV. These beam energies are much lower than the typical operating energies of the helium ion microscope or gallium focused ion beam systems. We demonstrate how low energy can be advantageous in ion microscopy when detecting backscattered ions, due to a decreased interaction volume and the potential for surface sensitive composition analysis. As an example application that demonstrates these advantages, we non-destructively image the removal of a thin residual resist layer during plasma etching in a nano-imprint lithography process. - Highlights: • We use an ion source based on photoionization of laser-cooled lithium atoms. • The ion source makes possible a low energy (500 eV to 5 keV) scanning ion microscope. • Low energy is preferred for ion microscopy with backscattered ions. • We use the microscope to image a thin resist used in nano-imprint lithography

Violencia sexual entre compañeros y violencia en parejas adolescentes

OpenAIRE

Ortega Ruiz, Rosario; Ortega Rivera, Francisco Javier; Sánchez Jiménez, Virginia

2008-01-01

El presente estudio ha analizado la presencia de violencia sexual entre compañeros y en las parejas adolescentes y jóvenes. Específicamente se han estudiado las diferencias por sexo, edad y estadio de la relación sentimental tanto en violencia sexual entre iguales como en las parejas, en una muestra de 490 adolescentes (55,7% chicos, 44,3% chicas, edad media 16.08 años). Los resultados descriptivos mostraron la misma incidencia de violencia sexual entre iguales y en las pa...

Ion microtomography using ion time-of-flight

International Nuclear Information System (INIS)

Roberts, M.L.; Heikkinen, D.W.; Proctor, I.D.; Pontau, A.E.; Olona, G.T.; Felter, T.E.; Morse, D.H.; Hess, B.V.

1992-01-01

We have developed and are in the process of testing an ion time-of-flight (TOF) detector system for use in our ion microtomography measurements. Using TOF, ion energy is determined by measurement of the ion's flight time over a certain path length. For ion microtomography, the principle advantage of TOF analysis is that ion count rates of several hundred thousand counts per second can be achieved as compared to a limit of about ten thousand ions per second when using a solid-state silicon surface barrier detector and associated electronics. This greater than 10 fold increase in count rate correspondingly shortens sample analysis time or increases the amount of data that can be collected on a given sample. Details of the system and progress to date are described

Arquitectura de comunicación entre frameworks jadesymfony

OpenAIRE

RODRÍGUEZ C., PAOLA J.; GÓMEZ R., SANTIAGO

2009-01-01

La inclusión del uso de Agentes dentro del campo del desarrollo de software es una de las principales áreas de estudio en la actualidad. Específicamente, el desarrollo de aplicaciones Web que aprovechen las ventajas que ofrece la tecnología de agentes y en especial las distintas propuestas de comunicación entre frameworks son esfuerzos importantes dentro de este campo. En este sentido, este artículo describe una arquitectura de comunicación entre dos de los principales frameworks de desarroll...

Ion implantation

International Nuclear Information System (INIS)

Dearnaley, Geoffrey

1975-01-01

First, ion implantation in semiconductors is discussed: ion penetration, annealing of damage, gettering, ion implanted semiconductor devices, equipement requirements for ion implantation. The importance of channeling for ion implantation is studied. Then, some applications of ion implantation in metals are presented: study of the corrosion of metals and alloys; influence or ion implantation on the surface-friction and wear properties of metals; hyperfine interactions in implanted metals

Ion Beam Extraction by Discrete Ion Focusing

DEFF Research Database (Denmark)

2010-01-01

An apparatus (900) and methods are disclosed for ion beam extraction. In an implementation, the apparatus includes a plasma source (or plasma) (802) and an ion extractor (804). The plasma source is adapted to generate ions and the ion extractor is immersed in the plasma source to extract a fracti...

Ion creation, ion focusing, ion/molecule reactions, ion separation, and ion detection in the open air in a small plastic device.

Science.gov (United States)

Baird, Zane; Wei, Pu; Cooks, R Graham

2015-02-07

A method is presented in which ions are generated and manipulated in the ambient environment using polymeric electrodes produced with a consumer-grade 3D printer. The ability to focus, separate, react, and detect ions in the ambient environment is demonstrated and the data agree well with simulated ion behaviour.

RELACIÓN ENTRE DIFERENTES PRUEBAS DE CAMPO: FUERZA, POTENCIA Y VELOCIDAD

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Jessenia Hernández Elizondo

2003-12-01

Full Text Available Esta investigación tuvo como propósito principal el encontrar por medio de pruebas en las variables de fuerza, potencia y velocidad, la relación matemática existente entre estos tres constructos. Participaron 56 sujetos varones con edades entre 18 y 25 años. Con el fin de responder al objetivo del estudio, se les aplicaron pruebas de campo de fuerza (1RM de sentadilla completa y repeticiones máximas al 80% 60% 40% y 20%, de velocidad (30 metros lanzados y 30 metros sin impulso, y de potencia (salto vertical con contra-movimiento SVCM, salto vertical sin impulso SVSI y salto vertical con caída SVCC, para correlacionar las diferentes pruebas entre sí. Los datos fueron analizados por medio de la correlación de Pearson (r, para correlacionar parejas de pruebas y correlación canónica (Rc para correlacionar grupos de variables. A partir de cada correlación se obtuvo la varianza explicada (r2 la cual indica el porcentaje de relación compartida en escala de 0-100 que existe entre las pruebas. Según los datos obtenidos, no existe relación significativa (2.1% entre las pruebas de salto-sentadilla, ni relación significativa (5.1% entre las pruebas de velocidad- sentadilla, mientras que la relación salto- velocidad (62%, fue estadísticamente significativa (p < 0.05. La implicación de estos resultados podrían respaldar la idea de que la relación teórica que existe entre estos constructos, no es completamente cierta cuando éstos son medidos por medio de pruebas de campo.

A desnecessidade do trabalho entre pescadores artesanais

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Cristiano Wellington Norberto Ramalho

2015-04-01

Full Text Available As relações socioculturais e econômicas, entre alguns grupos de pescadores artesanais, não colocam como entes antagônicos trabalho e tempo livre. Do contrário, tais relações celebram aproximações entre saber-fazer pesqueiro, lazer e vida, formando e conformando um todo societário. Inseridos nesse quadro, estão os pescadores artesanais do mar-de-fora da praia de Suape, no município do Cabo de Santo Agostinho, litoral sul de Pernambuco, distante 50 km de Recife. Este artigo busca desvelar a mencionada moral do trabalho e do tempo livre no fazer cotidiano de pescadores dessa Praia, com base na pesquisa etnográfica e na história de vida de 13 pescadores. No geral, identificou-se que há uma moral do trabalho que se confunde à moral do tempo livre, pois o cerceamento de uma delas representa limites à outra. Assim, para esses homens, definir o que é um ser liberto ou cativo liga-se ao encontro indissociável, em termos práticos e simbólicos, entre as referidas morais, o que é essencial para classificar o fazer-se pescador artesanal em seu sentido pleno fundamentado na desnecessidade do trabalho.

Study of the effect of positive ions impinging sensitive emulsions in mass spectrography; Etude de l'action des ions positifs sur les emulsions sensibles en spectrographie de masse

Energy Technology Data Exchange (ETDEWEB)

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

1969-08-01

Experimental relationships have been established between the blackening of emulsions by impinging ions and the following parameters: number, mass and energy of impinging particles. Mean energy ions (about twenty keV) give rise to a latent image probably made of small specks of metallic silver located at the surface or in the bulk of the silver halide grain. A specific developer for ion sensitive emulsion was perfected. Sensitivity and detection threshold are increased by a factor of two or three, compared with values observed using a classical developer. Low energy particles sputtered from superficial layers of the emulsion by the impinging twenty keV ions, produce a latent image close to the surface of the silver halide grain. An oxidizing process bleaches superficial latent image and then reduces background fog. The improved signal over background ratio allows to observe lines undetectable when the plates are developed by usual process. (author) [French] On a etabli les relations experimentales entre le noircissement resultant de l'action des ions sur l'emulsion sensible et les parametres suivants: nombre de particules incidentes, masse et energie de ces particules. L'effet sur les grains d'halogenure d'argent a ete examine: les ions d'energie moyenne (de l'ordre de 20 keV) creent une image latente vraisemblablement constituee d'argent, situee a la fois a la surface et a l'interieur du grain. Un revelateur specifique pour le developpement des emulsions sensibles exposees aux ions a ete mis au point: il accroit la sensibilite d'un facteur deux a trois et le facteur de contraste par rapport a un revelateur usuel. Les particules de faible energie, emises par pulverisation des couches superficielles de l'emulsion au cours de l'enregistrement des spectres de masse des ions d'energie moyenne, creent essentiellement dans les grains d'halogenure d'argent, une image latente superficielle, responsable du fond. Un traitement oxydant est propose pour eliminer cette image en

El (los Sur buscando al Sur. Una construcción entre estereotipos y realidad.

Directory of Open Access Journals (Sweden)

Mabel Franzone

2010-11-01

Full Text Available Todas las lecturas que podamos hacer del Sur, de sus propias representaciones, de aquellas vehiculizadas por el Norte, de sus creaciones, de sus reacciones, de su búsqueda constante de identidad, son lecturas de múltiples situaciones, que llaman a cruces insoslayables entre pueblos, entre distintas etnias, entre disciplinas, entre sentimientos que van desde el rechazo hasta la atracción casi magnética entre los dos hemisferios. Nuestra intención primera era la de reunir de manera aproximativa las problemáticas actuales de los Sur, ligadas a lo imaginario.

Study of ion exchange equilibrium and determination of heat of ion exchange by ion chromatography

International Nuclear Information System (INIS)

Liu Kailu; Yang Wenying

1996-01-01

Ion chromatography using pellicularia ion exchange resins and dilute solution can be devoted to the study of ion exchange thermodynamics and kinetics. Ion exchange equilibrium equation was obtained, and examined by the experiments. Based on ion exchange equilibrium, the influence of eluent concentration and resin capacity on adjusted retention volumes was examined. The effect of temperature on adjusted retention volumes was investigated and heats of ion exchange of seven anions were determined by ion chromatography. The interaction between anions and skeleton structure of resins were observed

Entre ritmo e poesia: rap e literatura oral urbana

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Marcus Rogerio Salgado

2015-11-01

Full Text Available O objetivo do presente artigo é um estudo do rap enquanto manifestação de literatura oral urbana e forma de oralidade tecnológica. Para tanto, o artigo passará em revista as relações entre literatura e palavra falada/cantada, assim como as possibilidades de interface estética entre a literatura e a música que estão em questão quando tratamos do rap.

A FOTOGRAFIA ENTRE A ARTE POPULAR E A ARTE ERUDITA

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Marcos Fabris

2013-09-01

Full Text Available Este artigo pretende discutir alguns dos aspectos que marcam o estabelecimento e a dissolução das fronteiras entre dois pólos convencionalmente descritos como arte culta e arte popular, tecendo paralelos entre o teatro de variedades, forma de expressão popular por excelência, e a fotografia, expressão artística que desde seus primórdios circula entre os dois extremos deste contínuo. Nestes termos, ambiciona-se verificar como determinadas condições sócio-históricas favorecem a criação de recursos formais que minimizam, ou suprimem, tais distinções consagradas pela crítica de arte.

Polyatomic ions from a high current ion implanter driven by a liquid metal ion source

Science.gov (United States)

Pilz, W.; Laufer, P.; Tajmar, M.; Böttger, R.; Bischoff, L.

2017-12-01

High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi2+ ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

Proyectos educativos: estudio comparativo entre Venezuela y Colombia

Directory of Open Access Journals (Sweden)

Mineira Finol

2005-09-01

Full Text Available El Proyecto Educativo Integral Comunitario (PEIC y el Proyecto Educativo Institucional constituyen la categoría de comparación entre Venezuela y Colombia; a tal fin, este estudio de tipo comparativo-documental se centró en determinar congruencias y discrepancias entre PEIC y PEI, utilizando el método comparativo estructurado en cuatro fases: descripción, interpretación, yuxtaposición y comparación, propuesto por Hilker y Bereday (1972 Entre los resultados se tienen: congruencias en cuanto surgen sobre las bases de diagnóstico externos efectuados por organismos internacionales UNESCO, CEPAL ante la inefectividad y baja productividad de ambos países; a nivel interno responden a políticas educativas reformadoras de currículum y leyes,. Discrepancias referidas al tiempo de implementación; en Venezuela a partir de 1996; Colombia en 1992; este último, consolidó las bases para la participación a través del gobierno escolar y de un sistema de evaluación institucional, muy incipiente en Venezuela.

Experimental Evaluation of a Negative Ion Source for a Heavy Ion Fusion Negative Ion Driver

International Nuclear Information System (INIS)

Grisham, L.R.; Hahto, S.K.; Hahto, S.T.; Kwan, J.W.; Leung, K.N.

2004-01-01

Negative halogen ions have recently been proposed as a possible alternative to positive ions for heavy ion fusion drivers because electron accumulation would not be a problem in the accelerator, and if desired, the beams could be photo-detached to neutrals. To test the ability to make suitable quality beams, an experiment was conducted at Lawrence Berkeley National Laboratory using chlorine in an RF-driven ion source. Without introducing any cesium (which is required to enhance negative ion production in hydrogen ion sources) a negative chlorine current density of 45 mA/cm 2 was obtained under the same conditions that gave 57 45 mA/cm 2 of positive chlorine, suggesting the presence of nearly as many negative ions as positive ions in the plasma near the extraction plane. The negative ion spectrum was 99.5% atomic chlorine ions, with only 0.5% molecular chlorine, and essentially no impurities. Although this experiment did not incorporate the type of electron suppression technology that i s used in negative hydrogen beam extraction, the ratio of co-extracted electrons to Cl - was as low as 7 to 1, many times lower than the ratio of their mobilities, suggesting that few electrons are present in the near-extractor plasma. This, along with the near-equivalence of the positive and negative ion currents, suggests that the plasma in this region was mostly an ion-ion plasma. The negative chlorine current density was relatively insensitive to pressure, and scaled linearly with RF power. If this linear scaling continues to hold at higher RF powers, it should permit current densities of 100 45 mA/cm 2 , sufficient for present heavy ion fusion injector concepts. The effective ion temperatures of the positive and negative ions appeared to be similar and relatively low for a plasma source

Laser-cooled atomic ions as probes of molecular ions

Energy Technology Data Exchange (ETDEWEB)

Brown, Kenneth R.; Viteri, C. Ricardo; Clark, Craig R.; Goeders, James E.; Khanyile, Ncamiso B.; Vittorini, Grahame D. [Schools of Chemistry and Biochemistry, Computational Science and Engineering and Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2015-01-22

Trapped laser-cooled atomic ions are a new tool for understanding cold molecular ions. The atomic ions not only sympathetically cool the molecular ions to millikelvin temperatures, but the bright atomic ion fluorescence can also serve as a detector of both molecular reactions and molecular spectra. We are working towards the detection of single molecular ion spectra by sympathetic heating spectroscopy. Sympathetic heating spectroscopy uses the coupled motion of two trapped ions to measure the spectra of one ion by observing changes in the fluorescence of the other ion. Sympathetic heating spectroscopy is a generalization of quantum logic spectroscopy, but does not require ions in the motional ground state or coherent control of the ion internal states. We have recently demonstrated this technique using two isotopes of Ca{sup +} [Phys. Rev. A, 81, 043428 (2010)]. Limits of the method and potential applications for molecular spectroscopy are discussed.

Consumo de álcool e violência entre adolescentes argentinos

Directory of Open Access Journals (Sweden)

Mariaelena Pierobon

2013-02-01

Full Text Available OBJETIVO: Este estudo investigou a associação entre álcool e violência na população de jovens argentinos. MÉTODOS: Dados da Global School-based Student Health Survey (GSHS de 2007, uma pesquisa representativa em termos nacionais com alunos do ensino médio, foram examinados utilizando-se modelos de regressão logística ajustados por idade. RESULTADOS: Dos 1328 alunos participantes entre 13 e 15 anos de idade, 51,9% declararam ter consumido álcool no último mês, com taxas mais elevadas entre meninos (p = 0,04 e alunos mais velhos (p < 0,01. Homens e mulheres que bebem demonstraram estar quase duas vezes mais propensos a relatar agressão física, quando em uma briga física, e pensamentos sobre violência autoinfligida do que aqueles que não bebem. Entre as pessoas que bebem, aquelas que reportaram saúde mental precária, haviam sido vítimas de bullying, fumavam, faziam uso de drogas ou abandonaram a escola sem permissão se mostraram duas vezes mais propensas ao envolvimento em atividades violentas do que outras pessoas que também bebem. CONCLUSÃO: Intervenções de saúde pública quanto à violência entre jovens adolescentes devem ser desenvolvidas em combinação com programas de educação sobre álcool.

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

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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

A novel ion imager for secondary ion mass spectrometry

International Nuclear Information System (INIS)

Matsumoto, Kazuya; Miyata, Kenji; Nakamura, Tsutomu

1993-01-01

This paper describes a new area detector for secondary ion mass spectrometry (SIMS) ion microscope, and its performance. The operational principle is based on detecting the change in potential of a floating photodiode caused by the ion-induced secondary-electron emission and the incoming ion itself. The experiments demonstrated that 10 1 -10 5 aluminum ions per pixel can be detected with good linear response. Moreover, relative ion sensitivities from hydrogen to lead were constant within a factor of 2. The performance of this area detector provides the potential for detection of kiloelectronvolt ion images with current ion microscopy

Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy,and Related Fields

International Nuclear Information System (INIS)

Grisham, L.R.; Kwan, J.W.

2008-01-01

Some years ago it was suggested that halogen negative ions could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons - can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion - ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.

Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

International Nuclear Information System (INIS)

Grisham, L.R.; Kwan, J.W.

2008-01-01

Some years ago it was suggested that halogen negative ions (1)could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion-ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component--positive ions, negative ions, and electrons--can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion-ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed

Soporte social, familiar y autoconcepto: relación entre los constructos

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Makilim Nunes Baptista

2012-01-01

Full Text Available El objetivo del estudio fue verificar las asociaciones entre el soporte social, el soporte familiar y el autoconcepto en un grupo de hombres y mujeres. En el caso de los hombres hubo correlaciones negativas entre el soporte familiar y los factores negligencia, agresividad e indiferencia del instrumento de autoconcepto. En el grupo de mujeres el soporte familiar total fue correlacionado positivamente con sensualidad y responsabilidad, y negativamente con inseguridad, siendo las tres medidas del instrumento de autoconcepto. Al considerar las relaciones entre el soporte familiar y el soporte social, todas fueron positivas, tanto en los hombres como en las mujeres.

PENGARUH PANJANG ENTRES TERHADAP KEBERHASILAN PENYAMBUNGAN TANAMAN ALPUKAT (PERSEA AMERICANA MILL.

Directory of Open Access Journals (Sweden)

Dirgahani Putri

2016-06-01

Full Text Available Beragamnya hasil produksi dan kualitas buah alpukat dapat diperbaiki dengan metode penyambungan. Penyambungan merupakan kegiatan untuk mengga-bungkan dua atau lebih sifat unggul dalam satu tanaman. Penelitian ini bertujuan mengetahui pengaruh berbagai panjang entres terhadap keberhasilan penyam-bungan tanaman alpukat. Rancangan percobaan yang digunakan dalam penelitian ini adalah Rancangan Acak Kelompok dengan lima perlakuan panjang entres, yaitu 3 cm, 6 cm, 9 cm, 12 cm, dan 15 cm.Setiap perlakuan diulang sebanyak lima kali dan setiap perlakuan terdiri atas lima tanaman;sehingga jumlah totalnya sebanyak 125 tanaman. Pengamatan dilakukan pada peubah persentase sambung hidup, jumlah tunas, panjang tunas, jumlah daun, dan diameter batang atas. Berbagai panjang entres tidak memberikan pengaruh yang nyata pada peubah persentase sambung hidup, panjang tunas terpanjang, jumlah daun, dan diameter batang atas tetapi berpengaruh nyata pada peubah jumlah tunas. Perlakuan panjang entres 15 cm memberikan hasil tertinggi untuk jumlah tunas, panjang tunas, jumlah daun dan diameter batang atas, sedangkan untuk persentase hidup perlakuan 6 cm, 12 cm memberikan hasil tertinggi yaitu 100%. Perlakuan panjang entres 3 cm adalah perlakuan yang memberikan pengaruh yang rendah pada persentase sambung hidup (yaitu 92%, peubah jumlah tunas, panjang tunas, serta diameter batang atas pada berbagai umur tanaman alpukat.

Aborto entre alunas e funcionárias de uma universidade brasileira

Directory of Open Access Journals (Sweden)

Hardy Ellen

1993-01-01

Full Text Available No Brasil existem poucas informações sobre o aborto provocado e suas características na população. A dificuldade em se obter dados confiáveis deve-se: à sua ilegalidade, e também ao fato de que a maioria dos estudos é realizada em hospitais. Assim, em 1990, foi realizada pesquisa entre alunas da graduação e funcionárias de uma universidade brasileira. Os dados foram obtidos por meio de questionário, auto-respondido, para devolução por correio, anonimamente. Os resultados apresentados referem-se à freqüência do aborto provocado nesta população. Encontrou-se que quatro vezes menos alunas do que funcionárias tinham engravidado alguma vez (15% e 65%; 9% das alunas e 14% das funcionárias tiveram aborto provocado. Entre as mulheres que engravidaram alguma vez, as alunas tiveram mais aborto provocado do que as funcionárias (59% e 20%. Quando controladas por grupo etário as diferenças entre as alunas e funcionárias mantiveram-se. Entretanto, entre as alunas, o aborto provocado foi mais freqüente entre as mais jovens.

Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.

Science.gov (United States)

Kondo, K; Kanesue, T; Tamura, J; Okamura, M

2010-02-01

Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.

Ion-Beam-Excited Electrostatic Ion Cyclotron Waves

DEFF Research Database (Denmark)

Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

1976-01-01

Self-excited electrostatic ion cyclotron waves were observed in an ion-beam-plasma system produced in a DP-operated Q-machine. The frequency of the waves showed the theoretically predicted variation with the magnetic field.......Self-excited electrostatic ion cyclotron waves were observed in an ion-beam-plasma system produced in a DP-operated Q-machine. The frequency of the waves showed the theoretically predicted variation with the magnetic field....

Encuentros improbables: Cervantes y Shakespeare entre Borges y Burgess

OpenAIRE

Martínez, Zenón Luis

2016-01-01

En sus biografías sobre Cervantes y Shakespeare, Luis Astrana Marín especuló con un encuentro entre ambos con ocasión de la ratificación en 1605 en Valladolid del Tratado de Londres. Este improbable encuentro ha seguido alimentando ficciones históricas y fantasías literarias. El cruce de caminos entre Cervantes y Shakespeare tiene lugar en torno a la perdida tragicomedia The History of Cardenio (1612?), atribuida a John Fletcher y William Shakespeare. La recon...

Intermediate energies heavy ion collisions : study of the charged particles emission dynamics and emitters characterization; Collisions d`ions lourds aux energies intermediaires: etude de la dynamique d`emission des particules chargees et caracterisation des emetteurs

Energy Technology Data Exchange (ETDEWEB)

Bauge, E

1994-07-01

In heavy ion collisions at intermediate energies, reaction processes are ranging from slow processes where equilibrium is achieved between every emission, up to direct processes where nucleon nucleon scattering and phase space availability are the deciding factors. In order to investigate this transition, both the emission dynamics and the characteristics of the emitter have been studied, both theoretically and experimentally in the AMPHORA detector, for the systems 7, 17, 27 and 34 AMeV, {sup 40}Ar+Al, {sup 40}Ar+Cu and {sup 40}Ar+Ag. First, the linear momentum transfer of the most central collisions has been evaluated for these systems, by measuring the velocity of heavy residues. Then, by measuring azimuthal angle correlations functions, and by comparing them with statistical model predictions, the average angular momentum of the emitter has been evaluated. To study the charged particles emission dynamics, experimental azimuthal angle and relative momentum correlation functions have been compared with simulations based on a classical trajectory model. Finally, predictions of an advanced BUU model have been studied for the system 34 AMeV 40 Ar+Al. (authors). 69 refs., 52 figs., 5 tabs.

La religiosidad popular como “entre-medio” entre la religión institucional y la espiritualidad individualizada = Popular religion as “in between” institutional religion and individual spirituality

Directory of Open Access Journals (Sweden)

Torre, Renée de la

2012-01-01

Full Text Available Neste artigo se argumenta a relevância do estudo da religiosidade popular para entender as novas formas da religiosidade contemporânea no contexto latinoamericano. Diferente das posturas teóricas dos sociólogos da religião europeia, que assinalam a pertinência do indivíduo como unidade analítica para entender as transformações religiosas próprias da pós-modernidade, este artigo argumenta que a religiosidade popular – entendida como “entre-meio” entre o tradicional e o emergente, entre o local e o transnacional, entre o social e o individual e entre a sacralidade profana e a profanação da religiosidade tradicional – permite entender os fenômenos em que a religiosidade se pratica nas margens da instituição (próprias das expressões new age e neoesotéricas, mas sem desatender os processos em que se legitimam as novas formas desinstitucionalizadas da religiosidade, buscando âncoras e linhagens que geram a continuidade do peso da tradição da religiosidade popular

Ion mobilities and ion-atom interaction potentials

International Nuclear Information System (INIS)

Gatland, I.R.

1982-01-01

The techniques for measuring the mobilities of ions in gases, relating interaction potentials to mobilities, and determining potentials from experimental mobilities are reviewed. Applications are presented for positive alkali ions and negative halogen ions in inert gases. (Auth.)

Low-altitude ion heating with downflowing and upflowing ions

Science.gov (United States)

Shen, Y.; Knudsen, D. J.; Burchill, J. K.; Howarth, A. D.; Yau, A. W.; James, G.; Miles, D.; Cogger, L. L.; Perry, G. W.

2017-12-01

Mechanisms that energize ions at the initial stage of ion upflow are still not well understood. We statistically investigate ionospheric ion energization and field-aligned motion at very low altitudes (330-730 km) using simultaneous plasma, magnetic field, wave electric field and optical data from the e-POP satellite. The high-time-resolution (10 ms) dataset enables us to study the micro-structures of ion heating and field-aligned ion motion. The ion temperature and field-aligned bulk flow velocity are derived from 2-D ion distribution functions measured by the SEI instrument. From March 2015 to March 2016, we've found 17 orbits (in total 24 ion heating periods) with clear ion heating signatures passing across the dayside cleft or the nightside auroral regions. Most of these events have consistent ion heating and flow velocity characteristics observed from both the SEI and IRM instruments. The perpendicular ion temperature goes up to 4.5 eV within a 2 km-wide region in some cases, in which the Radio Receiver Instrument (RRI) sees broadband extremely low frequency (BBELF) waves, demonstrating significant wave-ion heating down to as low as 350 km. The e-POP Fast Auroral Imager (FAI) and Magnetic Field (MGF) instruments show that many events are associated with active aurora and are within downward current regions. Contrary to what would be expected from mirror-force acceleration of heated ions, the majority of these heating events (17 out of 24) are associated with the core ion downflow rather than upflow. These statistical results provide us with new sights into ion heating and field-aligned flow processes at very low altitudes.

Design and simulation of ion optics for ion sources for production of singly charged ions

Science.gov (United States)

Zelenak, A.; Bogomolov, S. L.

2004-05-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments.

Design and simulation of ion optics for ion sources for production of singly charged ions

International Nuclear Information System (INIS)

Zelenak, A.; Bogomolov, S.L.

2004-01-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments

Relación entre calidad del semen y la edad

Directory of Open Access Journals (Sweden)

John Chávez

2012-07-01

Full Text Available Objetivo: Determinar la relación entre la calidad del semen humano y la edad. Material y Métodos: El espermatograma se realizó siguiendo el Manual de Laboratorio de la OMS para el examen del Semen Humano y de la Interacción Moco Cervical y Semen (1999, de los exámenes realizados entre julio 2003 a diciembre 2008. Se estudiaron 2 441 casos de varones que cumplen con los criterios de inclusión. Resultados: La motilidad A+B fue de 51,55% para varones de 20 a 29 años; los espermatozoides normales fue de 77,73% para varones mayores de 50 años; el recuento espermático (mill/ml fue de 61,09 para varones mayores de 50 años.La evaluación de la motilidad espermática tuvo como coeficiente de correlación lineal múltiple de 0,222 y coeficiente de determinación de 0,049; en la morfología espermática, coeficiente de correlación lineal de 0,0622 y coeficiente de determinación de 0,0039; en el recuento espermático, coeficiente de correlación lineal múltiple de 0,465 y coeficiente de determinación de 0,216. Conclusiones: existe una tendencia inversa entre la motilidad y la edad, una tendencia directa entre el recuento espermático y la edad, y una tendencia constante entre morfología espermática y edad.

Crater formation by single ions, cluster ions and ion "showers"

CERN Document Server

Djurabekova, Flyura; Timko, Helga; Nordlund, Kai; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter

2011-01-01

The various craters formed by giant objects, macroscopic collisions and nanoscale impacts exhibit an intriguing resemblance in shapes. At the same time, the arc plasma built up in the presence of sufficiently high electric fields at close look causes very similar damage on the surfaces. Although the plasma–wall interaction is far from a single heavy ion impact over dense metal surfaces or the one of a cluster ion, the craters seen on metal surfaces after a plasma discharge make it possible to link this event to the known mechanisms of the crater formations. During the plasma discharge in a high electric field the surface is subject to high fluxes (~1025 cm-2s-1) of ions with roughly equal energies typically of the order of a few keV. To simulate such a process it is possible to use a cloud of ions of the same energy. In the present work we follow the effect of such a flux of ions impinging the surface in the ‘‘shower’’ manner, to find the transition between the different mechanisms of crater formati...

Performance of the Alice muon spectrometer. Weak boson production and measurement in heavy-ion collisions at LHC; Performance du spectrometre a muons d'ALICE. Production et mesure des bosons faibles dans des collisions d'ions lourds aupres du LHC

Energy Technology Data Exchange (ETDEWEB)

Conesa del valle, Z

2007-07-15

Lattice QCD predicts a transition from a hadronic phase to a Quark Gluon Plasma phase, QGP, for temperatures above 10{sup 13} K. Heavy-ion collisions are proposed to recreate it in laboratory. With such a purpose, the LHC (Large Hadron Collider) will provide Pb-Pb collisions at 5.5 TeV/u, and the ALICE experiment will permit to explore them. In particular, the ALICE muon spectrometer will permit to investigate the muon related probes (quarkonia, open beauty,...). The expected apparatus performances to measure muons and dimuons are discussed. A factorization technique is employed to unravel the different contributions to the global efficiency. Results indicate that the detector should be able to measure muons up to pT {approx} 100 GeV/c with a resolution of about 10 per cent. We show that weak bosons production could be measured for the first time in heavy-ion collisions. Single muon p{sub T} and dimuons invariant mass distributions will probe W and Z production. As mainly muons from b- and c-quarks decays will populate the intermediate-p{sub T} of 5 - 25 GeV/c, heavy quark in-medium energy loss calculations indicate that the single muon spectra would be suppressed by a factor 2-4 in the most central 0 - 10% Pb-Pb collisions at 5.5 TeV. However, for p{sub T} > 35 GeV/c the weak boson decays are predominant, and no suppression is expected. Estimations indicate that the b- and W-muons crossing point shifts down in transverse momenta by 5 to 7 GeV/c in the most central 0 - 10% Pb-Pb collisions at 5.5 TeV. (author)

relaPro : Base de datos para encontrar relaciones entre proyectos

OpenAIRE

Fortis Urbano, Julio

2015-01-01

Desarrollo de una base de datos para almacenar proyectos y una aplicación web de ejemplo que permite encontrar elementos comunes entre los proyectos almacenados en el sistema. Desenvolupament d'una base de dades per emmagatzemar projectes i una aplicació web d'exemple que permet trobar elements comuns entre els projectes emmagatzemats en el sistema. Bachelor thesis for the Computer Science program on Databases.

Single-ion conducting diblock terpolymers for lithium-ion batteries

Science.gov (United States)

Morris, Melody; Epps, Thomas H., III

Block polymer (BP) electrolytes provide an attractive route to overcome the competing constraints of high conductivity and mechanical/thermal stability in lithium-ion batteries through nanoscale self-assembly. For example, macromolecules can be engineered such that one domain conducts lithium ions and the other prevents lithium dendrite formation. Herein, we report on the behavior of a single-ion conducting BP electrolyte that was designed to facilitate the transport of lithium ions. These polymers differ from traditional salt-doped BP electrolytes, which require the addition of a lithium salt to bestow conductivity and typically suffer from substantial counterion motion that reduces efficiency. New single-ion BPs were synthesized, and the nanoscale morphologies were determined using small angle X-ray scattering and transmission electron microscopy. Electrolyte performance was measured using AC impedance spectroscopy and DC polarization, and the results were correlated to nanoscale morphology and ion content. Enhanced physical understanding of single-ion BPs was gained by connecting the ion mobility to the chemistry, chain structure, and ion content of the single-ion BP. These studies can be applied to other charged-neutral block polymers to elucidate the effects of ion content on self-assembly and macroscopic properties.

Cooperación; altruismo en las relaciones entre aerolíneas

OpenAIRE

Fernández Lerate, Elisa M.

2016-01-01

El presente estudio se centra en analizar unas determinadas relaciones cooperativas entre compañías aéreas, con la intención de investigar si sacan provecho o no de dichas relaciones. La cooperación entre esas compañías aéreas puede presentar comportamientos más altruistas o más oportunistas. Para centrar el tema del estudio, se van a analizar los acuerdos de códigos compartidos que llevan a cabo entre ellas. Los datos de cooperación a través de código compartido permitirán conocer qué porcen...

Enhanced ion acoustic fluctuations and ion outflows

Directory of Open Access Journals (Sweden)

F. R. E. Forme

1999-02-01

Full Text Available A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acoustic lines. This spectral asymmetry and the intensity of the received signal cannot be resolved by the standard analysis procedure and often causes its failure. As a result, and in spite of a very clear spectral signature, the analysis is unable to fit the plasma parameters inside the regions of ion acoustic turbulence. We present European Incoherent Scatter radar (EISCAT observations of large ion outflows associated with the simultaneous occurrence of enhanced ion acoustic echoes. The ion fluxes can reach 1014 m-2 s-1 at 800 km altitude. From the very clear spectral signatures of these echoes, a method is presented to extract estimates of the electron temperature and the ion drift within the turbulent regions. It is shown that the electron gas is strongly heated up to 11 000 K. Also electron temperature gradients of about 0.02 K/m exist. Finally, the estimates of the electron temperature and of the ion drift are used to study the possible implications for the plasma transport inside turbulent regions. It is shown that strong electron temperature gradients cause enhancement of the ambipolar electric field and can account for the observed ion outflows.Key words. Ionosphere (auroral ionosphere; ionosphere · magnetosphere interactions; plasma waves and instabilities.

Ion sources for heavy ion fusion

International Nuclear Information System (INIS)

Yu, S.S.; Eylon, S.; Chupp, W.

1995-09-01

The development of ion sources for heavy ion fusion will be reported with particular emphasis on a recently built 2 MV injector. The new injector is based on an electrostatic quadrupole configuration, and has produced pulsed K + ions of 950 mA peak from a 6.7 inch curved alumino silicate source. The ion beam has reached 2.3 MV with an energy flatness of ±0.2% over 1 micros. The measured normalized edge emittance of less than 1 π mm-mr is close to the source temperature limit. The design, construction, performance, and comparisons with three-dimensional particle-in-cell simulations will be described

Dynamic problems of power reactors and analogic devices; Les problemes dynamiques du reacteur de puissance et les machines analogiques

Energy Technology Data Exchange (ETDEWEB)

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

1955-07-01

The raise of the nuclear physics came with heavy mathematical developments. The analogical installations became especially useful for precise calculations of parameters which depend the running of a reactor. They permit between other to study of kinetic problems and especially ''cybernetics'' of nuclear reactors. It doesn't make a doubt that their use will become widespread, not only in the calculations laboratories, in services for servo-mechanisms study, but also in the control panels of the reactors themselves. (M.B.) [French] L'essor de la physique nucleaire s'est accompagne de lourds developpements mathematiques. Les montages analogiques sont devenus particulierement utiles pour les calculs precis des parametres dont depend le fonctionnement d'un reacteur. Elles permettent entre autre l'etude des problemes cinetiques et surtout ''cybernetiques'' des reacteurs nucleaires. Il ne fait pas de doute que leur usage se generalisera, non seulement dans les laboratoires de calculs, les services d'etudes de servomecanismes, mais aussi pres des tableaux de commande des reacteurs eux-memes. (M.B.)

Ion-ion interaction and energy transfer of 4+ transuranium ions in cerium tetrafluoride

International Nuclear Information System (INIS)

Liu, G.K.; Beitz, J.V.

1990-01-01

Dynamics of excited 5f electron states of the transuranium ions Cm 4+ and Bk 4+ in CeF 4 are compared. Based on time- and wavelength-resolved laser-induced fluorescence, excitation energy transfer processes have been probed. Depending on concentration and electronic energy level structure of the studied 4+ transuranium ion, the dominant energy transfer mechanisms were identified as cross relaxation, exciton-exciton annihilation, and trapping. Energy transfer rates derived from the fitting of the observed fluorescence decays to theoretical models, based on electric multipolar ion-ion interactions, are contrasted with prior studies of 4f states of 3+ lanthanide and 3d states of transition metal ions. 16 refs., 1 tab

Ion beam monitoring

International Nuclear Information System (INIS)

McKinney, C.R.

1980-01-01

An ion beam analyzer is specified, having an ion source for generating ions of a sample to be analyzed, means for extracting the sample ions, means for focusing the sample ions into a beam, separation means positioned along the ion beam for selectively deflecting species of ions, and means for detecting the selected species of ions. According to the specification, the analyzer further comprises (a) means for disabling at least a portion of the separation means, such that the ion beam from the source remains undeflected; (b) means located along the path of the undeflected ion beam for sensing the sample ions; and (c) enabling means responsive to the sensing means for automatically re-enabling the separation means when the sample ions reach a predetermined intensity level. (author)

Las relaciones de comercio e inversión entre Colombia y Venezuela

OpenAIRE

Eglé Iturbe de Blanco

1997-01-01

Venezuela y Colombia cuentan con una larga trayectoria histórica en sus relaciones económicas. Comercian entre ellas y sus nacionales a lo largo de la frontera desde su nacimiento como naciones e interactúan entre ambos países como si fuera uno solo. Al norte, en la península de la Guajira, viven poblaciones indígenas comunes cuyo sustento es el comercio entre ambos lados de la frontera; y al sur, en los estados andinos venezolanos limítrofes con los llanos colombianos, tradicionalmente se ha...

Ion acoustic solitons/double layers in two-ion plasma revisited

International Nuclear Information System (INIS)

Lakhina, G. S.; Singh, S. V.; Kakad, A. P.

2014-01-01

Ion acoustic solitons and double layers are studied in a collisionless plasma consisting of cold heavier ion species, a warm lighter ion species, and hot electrons having Boltzmann distributions by Sagdeev pseudo-potential technique. In contrast to the previous results, no double layers and super-solitons are found when both the heavy and lighter ion species are treated as cold. Only the positive potential solitons are found in this case. When the thermal effects of the lighter ion species are included, in addition to the usual ion-acoustic solitons occurring at M > 1 (where the Mach number, M, is defined as the ratio of the speed of the solitary wave and the ion-acoustic speed considering temperature of hot electrons and mass of the heavier ion species), slow ion-acoustic solitons/double layers are found to occur at low Mach number (M < 1). The slow ion-acoustic mode is actually a new ion-ion hybrid acoustic mode which disappears when the normalized number density of lighter ion species tends to 1 (i.e., no heavier species). An interesting property of the new slow ion-acoustic mode is that at low number density of the lighter ion species, only negative potential solitons/double layers are found whereas for increasing densities there is a transition first to positive solitons/double layers, and then only positive solitons. The model can be easily applicable to the dusty plasmas having positively charged dust grains by replacing the heavier ion species by the dust mass and doing a simple normalization to take account of the dust charge

Modélisation de la combustion de fuels lourds prenant en compte la dispersion des asphaltènes Modeling Heavy Fuel-Oil Combustion (While Considering Or Including Asphaltene Dispersion

Directory of Open Access Journals (Sweden)

Audibert F.

2006-11-01

Full Text Available Divers modèles, ayant pour but de prédire le taux d'imbrûlés solides lors de la combustion du fuel lourd, ont été mis au point dans le passé. Les paramètres entrant en ligne de compte sont le plus souvent les teneurs en résidus lourds hydrocarbonés (asphaltènes précipités au pentane ou à l'heptane et carbone Conradson et en métaux : c'est le cas des modèles Exxon et Shell développés respectivement en 1979 et 1981. D'autres modèles tiennent compte, en plus de la composition du fuel, de son mode d'atomisation, de son mode de diffusion dans le foyer et de la cinétique de combustion : on peut citer les travaux du Laboratoire Energie du MIT publiés en 1986. Néanmoins, ces facteurs ne sont pas les seuls à intervenir : l'expérience a montré que l'état de dispersion des asphaltènes peut jouer également un grand rôle, notamment dans le cas d'installations de combustion à injection mécanique, pour lesquelles la dispersion des gouttelettes n'est pas aussi fine que pour des installations munies d'une injection assistée par la vapeur. Cette influence de la dispersion des asphaltènes sur la combustion a été mise en évidence dans le passé par l'utilisation d'additifs dispersants et également par la combustion de fuels lourds constitués par dilution d'asphaltes précipités au pentane avec un gas-oil de cracking catalytique de raffinerie (LCO. Ce sont ces fuels que l'on a considérés dans la présente étude. L'effet de ce facteur dispersion n'a pas été quantifié jusqu'alors, la difficulté étant de définir une grandeur mesurable représentant la répartition des agglomérats d'asphaltènes. Dans cette étude, on a essayé en un premier temps de faire une approche fractale de la répartition des asphaltènes à partir de clichés (préparés par la société Total, cette méthode ayant déjà été utilisée avec succès pour décrire des structures d'aspects comparables. Malheureusement, on s'est heurté à des

Relaciones entre los salarios y la productividad en Colombia

OpenAIRE

Méndez Sayago, Jhon Alexander

2017-01-01

Esta tesis de doctorado está compuesta de cuatro artículos que tienen como propósito estudiar las relaciones entre los salarios y la productividad laboral en Colombia. Los dos primeros artículos denominados “Salario real y eficiencia del trabajo en el sector manufacturero en Colombia” y “Análisis de causalidad y sensibilidad entre los salarios reales y la productividad laboral en el sector manufacturero a partir de cifras de los departamentos en Colombia” aportan evidencia empírica sobre la d...

Negative ion sources

International Nuclear Information System (INIS)

Ishikawa, Junzo; Takagi, Toshinori

1983-01-01

Negative ion sources have been originally developed at the request of tandem electrostatic accelerators, and hundreds of nA to several μA negative ion current has been obtained so far for various elements. Recently, the development of large current hydrogen negative ion sources has been demanded from the standpoint of the heating by neutral particle beam injection in nuclear fusion reactors. On the other hand, the physical properties of negative ions are interesting in the thin film formation using ions. Anyway, it is the present status that the mechanism of negative ion action has not been so fully investigated as positive ions because the history of negative ion sources is short. In this report, the many mechanisms about the generation of negative ions proposed so far are described about negative ion generating mechanism, negative ion source plasma, and negative ion generation on metal surfaces. As a result, negative ion sources are roughly divided into two schemes, plasma extraction and secondary ion extraction, and the former is further classified into the PIG ion source and its variation and Duoplasmatron and its variation; while the latter into reflecting and sputtering types. In the second half of the report, the practical negative ion sources of each scheme are described. If the mechanism of negative ion generation will be investigated more in detail and the development will be continued under the unified know-how as negative ion sources in future, the development of negative ion sources with which large current can be obtained for any element is expected. (Wakatsuki, Y.)

Experiments on Ion-Ion Plasmas From Discharges

Science.gov (United States)

Leonhardt, Darrin; Walton, Scott; Blackwell, David; Murphy, Donald; Fernsler, Richard; Meger, Robert

2001-10-01

Use of both positive and negative ions in plasma processing of materials has been shown to be advantageous[1] in terms of better feature evolution and control. In this presentation, experimental results are given to complement recent theoretical work[2] at NRL on the formation and decay of pulsed ion-ion plasmas in electron beam generated discharges. Temporally resolved Langmuir probe and mass spectrometry are used to investigate electron beam generated discharges during the beam on (active) and off (afterglow) phases in a variety of gas mixtures. Because electron-beam generated discharges inherently[3] have low electron temperatures (<0.5eV in molecular gases), negative ion characteristics are seen in the active as well as afterglow phases since electron detachment increases with low electron temperatures. Analysis of temporally resolved plasma characteristics deduced from these measurements will be presented for pure O_2, N2 and Ar and their mixtures with SF_6. Oxygen discharges show no noticeable negative ion contribution during the active or afterglow phase, presumably due to the higher energy electron attachment threshold, which is well above any electron temperature. In contrast, SF6 discharges demonstrate ion-ion plasma characteristics in the active glow and are completely ion-ion in the afterglow. Comparison between these discharges with published cross sections and production mechanisms will also be presented. [1] T.H. Ahn, K. Nakamura & H. Sugai, Plasma Sources Sci. Technol., 5, 139 (1996); T. Shibyama, H. Shindo & Y. Horiike, Plasma Sources Sci. Technol., 5, 254 (1996). [2] See presentation by R. F. Fernsler, at this conference. [3] D. Leonhardt, et al., 53rd Annual GEC, Houston, TX.

Detection of gold cluster ions by ion-to-ion conversion using a CsI-converter

International Nuclear Information System (INIS)

Nguyen, V.-T.; Novilkov, A.C.; Obnorskii, V.V.

1997-01-01

Gold cluster ions in the m/z range of 10 4 -2 x 10 6 u were produced by bombarding a thin film of gold with 252 Cf-fission fragments. The gold covering a C-Al substrate formed islets having a mean diameter of 44 A. Their size- and mass-distribution was determined by means of electron microscopy. The main task was to measure the m/z distribution of the cluster ions ejected from the sample surface. For this purpose we built a time-of-flight (TOF) mass spectrometer, which could be used as a linear TOF instrument or, alternatively, as a tandem-TOF instrument being equipped with an ion-to-ion converter. Combining the results obtained in both modes, it turned out that the linear TOF instrument equipped with micro-channel plates had a mean detection efficiency for 20 keV cluster ions of about 40%. In the tandem mode, the cluster ions hit a CsI converter with energies of 40z keV (z = charge state), from where secondary ions - mainly Cs + and (CsI) n Cs + cluster ions - were ejected. These ions were used to measure the TOF spectrum of the gold cluster ions. The detection efficiency of the cluster ions was found to vary in the available mass range from 99.7% to 96.5%. The complete mass distribution between 4 x 10 4 and 4 x 10 6 u was determined and compared with the corresponding mass distribution of the gold islets covering the substrate. (orig.)

La bioremédiation, ange ou démon ? Décryptage des risques émanant de la dépollution d’un environnement contaminé, illustré par la remédiation biologique de l’arsenic

OpenAIRE

Karlen, Stéphane

2014-01-01

La dégradation et la pollution de notre environnement ont de multiples origines et se déclinent en un phénomène complexe qu’il est difficile de disséquer. Les métaux lourds forment une catégorie particulière de polluants. Aujourd’hui, les métaux lourds libérés dans l’environnement proviennent d’émissions non contrôlées de fonderies et d’autres activités industrielles (surtout les mines), de l’évacuation de déchets industriels et du plomb que renferment les conduites d’eau, la peinture et l’es...

Highly Stripped Ion Sources for MeV Ion Implantation

Energy Technology Data Exchange (ETDEWEB)

Hershcovitch, Ady

2009-06-30

Original technical objectives of CRADA number PVI C-03-09 between BNL and Poole Ventura, Inc. (PVI) were to develop an intense, high charge state, ion source for MeV ion implanters. Present day high-energy ion implanters utilize low charge state (usually single charge) ion sources in combination with rf accelerators. Usually, a MV LINAC is used for acceleration of a few rnA. It is desirable to have instead an intense, high charge state ion source on a relatively low energy platform (de acceleration) to generate high-energy ion beams for implantation. This de acceleration of ions will be far more efficient (in energy utilization). The resultant implanter will be smaller in size. It will generate higher quality ion beams (with lower emittance) for fabrication of superior semiconductor products. In addition to energy and cost savings, the implanter will operate at a lower level of health risks associated with ion implantation. An additional aim of the project was to producing a product that can lead to long­ term job creation in Russia and/or in the US. R&D was conducted in two Russian Centers (one in Tomsk and Seversk, the other in Moscow) under the guidance ofPVI personnel and the BNL PI. Multiple approaches were pursued, developed, and tested at various locations with the best candidate for commercialization delivered and tested at on an implanter at the PVI client Axcelis. Technical developments were exciting: record output currents of high charge state phosphorus and antimony were achieved; a Calutron-Bemas ion source with a 70% output of boron ion current (compared to 25% in present state-of-the-art). Record steady state output currents of higher charge state phosphorous and antimony and P ions: P{sup 2+} (8.6 pmA), P{sup 3+} (1.9 pmA), and P{sup 4+} (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb{sup 3+} Sb {sup 4 +}, Sb{sup 5+}, and Sb{sup 6+} respectively. Ultimate commercialization goals did not succeed (even though a number of the products like high

Development of focused ion beam systems with various ion species

International Nuclear Information System (INIS)

Ji Qing; Leung, K.-N.; King, Tsu-Jae; Jiang Ximan; Appleton, Bill R.

2005-01-01

Conventional focused ion beam systems employ a liquid-metal ion source (LMIS) to generate high-brightness beams, such as Ga + beams. Recently there has been an increased need for focused ion beams in areas like biological studies, advanced magnetic-film manufacturing and secondary-ion mass spectroscopy (SIMS). In this article, status of development on focused ion beam systems with ion species such as O 2 + , P + , and B + will be reviewed. Compact columns for forming focused ion beams from low energy (∼3keV), to intermediate energy (∼35keV) are discussed. By using focused ion beams, a SOI MOSFET is fabricated entirely without any masks or resist

Elución de iones de níquel desde esferas de alginato en un medio ácido

Directory of Open Access Journals (Sweden)

Aracena, Alvaro

2016-03-01

Full Text Available Elution of nickel ions from alginate beads was studied in a temperature range of 2 to 80 °C and a sulfuric acid concentration between 0.005 to 2.5 g L−1. The elution mechanism was established by ion exchange between nickel and ions protons, obtaining a value of 93% elution at a temperature of 80 °C and a H2SO4 concentration of 0.25 g L−1. The influence of other acids on nickel elution was also studied. The nickel elution rate was significantly influenced by temperature and concentration of H2SO4. Elution kinetics of nickel ions was studied, and the 1-(1-α1/3=kappt model properly described the kinetics of this reaction. The dependence of nickel elution on the sulfuric acid concentration was of the order of 0.33. Moreover, the intrinsic rate constants were determined and an activation energy value of 54.5 kJ mol−1 was obtained for the temperature range studied. The results indicated that the nickel elution is a process controlled by chemical reactions.Se estudió la elución de iones de níquel desde esferas de alginato en un intervalo de temperaturas de 2 a 80 °C y una concentración de ácido sulfúrico entre 0,005 a 2,5 g L−1. El mecanismo de elución fue establecido por intercambio iónico entre protones e iones de níquel alcanzando valores de elución de 93% a una temperatura de 80 °C y concentración de H2SO4 de 0,25 g L−1. También se estudió la influencia de otros ácidos sobre la elución de níquel. La velocidad de elución de níquel fue significativamente influenciada por la temperatura y concentración de H2SO4. La cinética de elución de iones de níquel fue estudiada y el modelo 1-(1-α1/3=kappt describió muy bien la cinética de esta reacción. La dependencia de la elución de níquel sobre la concentración de ácido sulfúrico fue del orden de 0,33. Además, fueron determinadas las constantes de velocidad intrínseca y se obtuvo un valor de energía de activación de 54,5 kJ mol−1 para el intervalo de

Correlación entre homofobia y racismo en estudiantes de medicina

Directory of Open Access Journals (Sweden)

Adalberto Campo-Arias

2014-01-01

Full Text Available El objetivo de este estudio fue determinar la correlación entre homofobia y racismo en estudiantes de medicina de Bucaramanga (Colombia. Se realizó un estudio transversal que incluyó a estudiantes mayores de 18 años. La actitud hacia homosexuales (homofobia o prejuicio sexual se midió con la Escala de Homofobia (EHF y la actitud hacia afrocolombianos (el racismo o la discriminación racial, con una versión en español de la Escala de Racismo Moderno (MRS. La asociación entre homofobia y racismo se calculó con los coeficientes de Pearson (r y Spearman (rs. Un grupo de 334 estudiantes aceptó participar. La media para la edad fue 20,1 años (DE=1,9, 59,0 % eran mujeres. El alfa de Cronbach fue 0,78 para la EHF y 0,62 para la MRS. Las puntuaciones en la EHF fueron entre 7 y 34 (media=17,8; SD=5,4 y en la MRS, entre 0 y 34 (media=13,8; SD=5,2. El coeficiente r fue 0,35 (p<0,001 y rs, 0,34 (p<0,001. Se concluye que existe correlación positiva entre estas formas de prejuicio (la homofobia y el racismo en estudiantes de medicina de Bucaramanga. Se necesita una intervención para reducir los prejuicios en los estudiantes de medicina.

Ion colliders

Energy Technology Data Exchange (ETDEWEB)

Fischer, W.

2011-12-01

Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

Ion colliders

International Nuclear Information System (INIS)

Fischer, W.

2010-01-01

Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions (77Asb1, 81Bou1). The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

Study of the double charge-changing collision cross-sections of H{sup +}, D{sup +}, Li{sup +} ions with organic molecules in the energy range 10-50 keV; Etude des sections efficaces de double echange de charges ({sigma}{sub 1-1}) d'ions H{sup +}, D{sup +}, Li{sup +} traversant differents gaz organiques dans une gamme d'energie comprise entre 10 et 50 keV

Energy Technology Data Exchange (ETDEWEB)

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

1966-07-01

The variation of the double charge-changing collision cross-sections of H{sup +}, D{sup +}, Li{sup +} ions with organic molecules (CH{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, C{sub 4}H{sub 10}) in the energy range 10-50 keV has been studied. Several maximums for {sigma}{sub 1-1} = f(E) have been shown. Their existence should be explained by the different possibilities of dissociating the target-molecules. The position of the maximums, for the H{sup +} {yields} H{sup -} and D{sup +} {yields} D{sup -} reactions is in good agreement with that defined by the Massey adiabatic relation. (author) [French] Nous avons etudie la variation de la section efficace de double echange de charges des ions H{sup +}, D{sup +}, Li{sup +} lors de la collision avec les molecules organiques de CH{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, C{sub 4}H{sub 10} dans la gamme d'energie comprise entre 10 et 50 keV. Les resultats obtenus ont montre plusieurs maximums de {sigma}{sub 1-1} f(E). L'existence de ces maximums pourrait etre expliquee par les differentes possibilites de dissociation des molecules cibles. La position des points maximaux concernant les reactions H{sup +} {yields} H{sup -} et D{sup +} {yields} D{sup -} est en bon accord avec celle definie par la relation adiabatique de MASSEY. (auteur)

Ion Colliders

CERN Document Server

Fischer, W

2014-01-01

High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

Um mapeamento das aproximações entre Weber e Nietzsche

Directory of Open Access Journals (Sweden)

Leandro dos Santos

2014-06-01

Full Text Available Este artigo tem por objetivo um levantamento dos principais tópicos de aproximação entre a Sociologia de Max Weber (1864-1920 e a Filosofia de Friedrich W. Nietzsche (1844-1900. Para tanto, sublinharam-se os pontos mais expressivos e correntemente observados na literatura acerca das aproximações entre Weber e Nietzsche. Nesse sentido, os traços de maior afinidade foram encontrados nos seguintes temas: poder, conhecimento, modernidade e ética.

Production of highly charged ion beams from ECR ion sources

International Nuclear Information System (INIS)

Xie, Z.Q.

1997-09-01

Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ and U 34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

Cyberbullying: competencia social, motivación y relaciones entre iguales

Directory of Open Access Journals (Sweden)

2016-07-01

Full Text Available El reconocimiento de cierto solapamiento entre el acoso cara a cara (bullying y el ciberacoso (cyberbullying puede indicar que variables de cognición social, cuya influencia ha sido reconocida en el bullying, también estén presentes en el acoso cibernético. El objetivo de la investigación fue estudiar el ajuste social de los implicados en cyberbullying y analizar las diferencias en la percepción de la competencia social, la motivación y el apoyo de los iguales, entre víctimas, agresores y agresores victimizados del cyberbullying. Un total de 505 adolescentes (47,3% chicas con edades comprendidas entre los 12 y 16 años (M=13.95; DT=1.42 participaron en el estudio. Se utilizaron instrumentos para adolescentes validados en español y se analizaron las propiedades psicométricas para la adaptación de la escala de competencia social. Análisis factoriales exploratorios y confirmatorios mostraron índices óptimos de fiabilidad y validez. Se observó una mayor implicación de los ciberagresores victimizados. Las comparaciones entre roles a través de pruebas no paramétricas mostraron en los ciberagresores un mayor apoyo social que el resto de perfiles y altos niveles en metas de popularidad. Las cibervíctimas destacaron por su alta percepción de competencia social. Los ciberagresores victimizados mostraron altos niveles de metas de popularidad y baja aceptación social. Los resultados obtenidos permiten concluir que la forma en que el grupo de iguales gestiona su vida emocional y social puede estar explicando la situación de cyberbullying entre los adolescentes.

Entre formigas e estrelas

Directory of Open Access Journals (Sweden)

Vinicius Prates

2013-06-01

Full Text Available Esta resenha apresenta o livro Reagregando o social: uma introdução à teoria do ator-rede, última obra do filósofo francês Bruno Latour publicada no Brasil. Nele, o autor se propõe a elaborar uma suma da crítica que faz aos conceitos usualmente aceitos de “social”, o que vem desenvolvendo ao longo dos últimos anos de produção intelectual. Neste processo ele criou a “Teoria-ator-rede”, que busca reestabelecer teoricamente as relações entre o que chama de mediadores “humanos” e “não-humanos”.

Recoil ions

International Nuclear Information System (INIS)

Cocke, C.L.; Olson, R.E.

1991-01-01

The collision of a fast moving heavy ion with a neutral atomic target can produce very highly charged but slowly moving target ions. This article reviews experimental and theoretical work on the production and use of recoil ions beyond the second ionization state by beams with specific energies above 0.5 MeV/amu. A brief historical survey is followed by a discussion of theoretical approaches to the problem of the removal of many electrons from a neutral target by a rapid, multiply charged projectile. A discussion of experimental techniques and results for total and differential cross sections for multiple ionization of atomic and molecular targets is given. Measurements of recoil energy are discussed. The uses of recoil ions for in situ spectroscopy of multiply charged ions, for external beams of slow, highly charged ions and in ion traps are reviewed. Some possible future opportunities are discussed. (orig.)

Ion Elevators and Escalators in Multilevel Structures for Lossless Ion Manipulations

Energy Technology Data Exchange (ETDEWEB)

Ibrahim, Yehia M.; Hamid, Ahmed M.; Cox, Jonathan T.; Garimella, Venkata BS; Smith, Richard D.

2017-01-19

We describe two approaches based upon ion ‘elevator’ and ‘escalator’ components that allow moving ions to different levels in structures for lossless ion manipulations (SLIM). Guided by ion motion simulations we designed elevator and escalator components providing essentially lossless transmission in multi-level designs based upon ion current measurements. The ion elevator design allowed ions to efficiently bridge a 4 mm gap between levels. The component was integrated in a SLIM and coupled to a QTOF mass spectrometer using an ion funnel interface to evaluate the m/z range transmitted as compared to transmission within a level (e.g. in a linear section). Mass spectra for singly-charged ions of m/z 600-2700 produced similar mass spectra for both elevator and straight (linear motion) components. In the ion escalator design, traveling waves (TW) were utilized to transport ions efficiently between two SLIM levels. Ion current measurements and ion mobility (IM) spectrometry analysis illustrated that ions can be transported between TW-SLIM levels with no significant loss of either ions or IM resolution. These developments provide a path for the development of multilevel designs providing e.g. much longer IM path lengths, more compact designs, and the implementation of much more complex SLIM devices in which e.g. different levels may operate at different temperatures or with different gases.

Ion Elevators and Escalators in Multilevel Structures for Lossless Ion Manipulations.

Science.gov (United States)

Ibrahim, Yehia M; Hamid, Ahmed M; Cox, Jonathan T; Garimella, Sandilya V B; Smith, Richard D

2017-02-07

We describe two approaches based upon ion "elevator" and "escalator" components that allow moving ions to different levels in structures for lossless ion manipulations (SLIM). Guided by ion motion simulations, we designed elevator and escalator components based upon ion current measurements providing essentially lossless transmission in multilevel designs. The ion elevator design allowed ions to efficiently bridge a 4 mm gap between levels. The component was integrated in a SLIM and coupled to a QTOF mass spectrometer using an ion funnel interface to evaluate the m/z range transmitted as compared to transmission within a level (e.g., in a linear section). The analysis of singly charged ions of m/z 600-2700 produced similar mass spectra for both elevator and straight (linear motion) components. In the ion escalator design, traveling waves (TW) were utilized to transport ions efficiently between two SLIM levels. Ion current measurements and ion mobility (IM) spectrometry analysis illustrated that ions can be transported between TW-SLIM levels with no significant loss of either ions or IM resolution. These developments provide a path for the development of multilevel designs providing, e.g., much longer IM path lengths, more compact designs, and the implementation of much more complex SLIM devices in which, e.g., different levels may operate at different temperatures or with different gases.

The Fast-Casual Conundrum: Fast-Casual Restaurant Entrées Are Higher in Calories than Fast Food.

Science.gov (United States)

Schoffman, Danielle E; Davidson, Charis R; Hales, Sarah B; Crimarco, Anthony E; Dahl, Alicia A; Turner-McGrievy, Gabrielle M

2016-10-01

Frequently eating fast food has been associated with consuming a diet high in calories, and there is a public perception that fast-casual restaurants (eg, Chipotle) are healthier than traditional fast food (eg, McDonald's). However, research has not examined whether fast-food entrées and fast-casual entrées differ in calorie content. The purpose of this study was to determine whether the caloric content of entrées at fast-food restaurants differed from that found at fast-casual restaurants. This study was a cross-sectional analysis of secondary data. Calorie information from 2014 for lunch and dinner entrées for fast-food and fast-casual restaurants was downloaded from the MenuStat database. Mean calories per entrée between fast-food restaurants and fast-casual restaurants and the proportion of restaurant entrées that fell into different calorie ranges were assessed. A t test was conducted to test the hypothesis that there was no difference between the average calories per entrée at fast-food and fast-casual restaurants. To examine the difference in distribution of entrées in different calorie ranges between fast-food and fast-casual restaurants, χ(2) tests were used. There were 34 fast-food and 28 fast-casual restaurants included in the analysis (n=3,193 entrées). Fast-casual entrées had significantly more calories per entrée (760±301 kcal) than fast-food entrées (561±268; Prestaurants to determine whether the energy content or nutrient density of full meals (ie, entrées with sides and drinks) differs between fast-casual restaurants and fast-food restaurants. Calorie-conscious consumers should consider the calorie content of entrée items before purchase, regardless of restaurant type. Copyright © 2016 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Two-dimensional boundary-value problem for ion-ion diffusion

International Nuclear Information System (INIS)

Tuszewski, M.; Lichtenberg, A.J.

1977-01-01

Like-particle diffusion is usually negligible compared with unlike-particle diffusion because it is two orders higher in spatial derivatives. When the ratio of the ion gyroradius to the plasma transverse dimension is of the order of the fourth root of the mass ratio, previous one-dimensional analysis indicated that like-particle diffusion is significant. A two-dimensional boundary-value problem for ion-ion diffusion is investigated. Numerical solutions are found with models for which the nonlinear partial differential equation reduces to an ordinary fourth-order differential equation. These solutions indicate that the ion-ion losses are higher by a factor of six for a slab geometry, and by a factor of four for circular geometry, than estimated from dimensional analysis. The solutions are applied to a multiple mirror experiment stabilized with a quadrupole magnetic field which generates highly elliptical flux surfaces. It is found that the ion-ion losses dominate the electron-ion losses and that these classical radial losses contribute to a significant decrease of plasma lifetime, in qualitiative agreement with the experimental results

Ion Acceleration by Double Layers with Multi-Component Ion Species

Science.gov (United States)

Good, Timothy; Aguirre, Evan; Scime, Earl; West Virginia University Team

2017-10-01

Current-free double layers (CFDL) models have been proposed to explain observations of magnetic field-aligned ion acceleration in plasmas expanding into divergent magnetic field regions. More recently, experimental studies of the Bohm sheath criterion in multiple ion species plasma reveal an equilibration of Bohm speeds at the sheath-presheath boundary for a grounded plate in a multipole-confined filament discharge. We aim to test this ion velocity effect for CFDL acceleration. We report high resolution ion velocity distribution function (IVDF) measurements using laser induced fluorescence downstream of a CFDL in a helicon plasma. Combinations of argon-helium, argon-krypton, and argon-xenon gases are ionized and measurements of argon or xenon IVDFs are investigated to determine whether ion acceleration is enhanced (or diminished) by the presence of lighter (or heavier) ions in the mix. We find that the predominant effect is a reduction of ion acceleration consistent with increased drag arising from increased gas pressure under all conditions, including constant total gas pressure, equal plasma densities of different ions, and very different plasma densities of different ions. These results suggest that the physics responsible for acceleration of multiple ion species in simple sheaths is not responsible for the ion acceleration observed in these expanding plasmas. Department of Physics, Gettysburg College.

A singly charged ion source for radioactive 11C ion acceleration

Science.gov (United States)

Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K.

2016-02-01

A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

Ion microprobes

International Nuclear Information System (INIS)

Coles, J.N.; Long, J.V.P.

1977-01-01

An ion microprobe is described that has an ion extraction arrangement comprising two separate paths for ions and electrons diverging from a common point. A cone shaped or pyramidal guard electrode surrounds each path the apex angles being equal and coinciding with the said point. The guard electrodes are positioned to lie tangentially to each other and to a planar surface including the said point. An aperture is provided for the two paths at the apexes of both guard electrodes, and electrical connections between the guard electrodes enable the same potential to be applied to both guard electrodes. Means are provided for generating oppositely polarised electric fields within the guard electrodes, together with means for causing a focused ion beam to strike the common point without suffering astigmatism. The means for causing a focused ion beam to strike the said point includes an ion gun for directing an ion beam along one of the paths and means to provide an axial accelerating field there along. Optical viewing means are also provided. Existing designs enable only ions or electrons, but not both, to be extracted at any one time. (U.K.)

Ion acoustic waves in one- and two-negative ion species plasmas

International Nuclear Information System (INIS)

Ichiki, Ryuta; Shindo, Masako; Yoshimura, Shinji; Watanabe, Tsuguhiro; Kawai, Yoshinobu

2001-01-01

Ion acoustic waves in multi-ion plasmas including two negative ion species are investigated both numerically and experimentally. Numerically, the kinetic dispersion relation in two-negative ion plasmas is investigated. There are three modes of the ion acoustic waves in two-negative ion plasmas. In an Ar + -F - -SF 6 - plasma, only one of the three modes is dominant, regardless of the values of the electron and the ion temperatures. In a Xe + -F - -SF 6 - plasma, on the other hand, two modes can be important for a certain range of the electron-ion temperature ratio. The results also imply the possibility of the coexistence of the fast mode and the slow mode in one-negative ion plasmas. Experimentally, ion acoustic waves are observed in an Ar + -F - -SF 6 - plasma and are found to show a mode transition that agrees with the theoretical prediction for one of the three ion acoustic modes

Fusion at counterstreaming ion beams - ion optic fusion (IOF)

International Nuclear Information System (INIS)

Gryzinski, M.

1981-01-01

The results of investigation are briefly reviewed in the field of ion optic fusion performed at the Institute of Nuclear Research in Swierk. The ion optic fusion concept is based on the possibility of obtaining fusion energy at highly ordered motion of ions in counterstreaming ion beams. For this purpose TW ion beams must be produced and focused. To produce dense and charge-neutralized ion beams the selective conductivity and ballistic focusing ideas were formulated and used in a series of RPI devices with low-pressure cylindrical discharge between grid-type electrodes. 100 kA, 30 keV deuteron beams were successfully produced and focused into the volume of 1 cm 3 , yielding 10 9 neutrons per 200 ns shot on a heavy ice target. Cylindrically convergent ion beams with magnetic anti-defocusing were proposed in order to reach a positive energy gain at reasonable energy level. (J.U.)

Ions kinematics in an electrostatic ion beam trap

Energy Technology Data Exchange (ETDEWEB)

Attia, D

2004-06-01

In this study, I have tried to provide a better understanding of the dynamics of ions inside an electrostatic ion beam trap. The electrostatic ion trap allows to store ions moving between two electrostatic mirrors. Although the trap has been developed already seven years ago, no direct measurement of the transversal velocity distribution of the ions has been performed. Such quantity is central for understanding the conditions under which a beam should be produced (mainly emittance) in order to be trapped by such a device. The data I have obtained during the course of this work are based on an experimental technique which relies on the direct imaging of the particles exiting the trap, as well as on numerical simulations of the ion trajectories inside the trap. I have personally been involved in the hardware development of the imaging system, the data acquisition and analysis of the data as well as il all numerical calculations presented here. These results allow us to obtain, for the first time, experimental information on the transverse phase space of the trap, and contribute to the overall understanding of the ion motion in this system. (author)

Interactions entre muqueuse orale, salive et molécules de la flaveur

OpenAIRE

Ployon, Sarah

2016-01-01

Le rôle de la salive dans la perception sensorielle est de plus en plus reconnu, notamment par le biais des interactions physico-chimiques pouvant s’établir entre protéines salivaires et constituants alimentaires. Ce travail s’intéresse à la pellicule salivaire, la couche de protéines salivaires ancrées aux cellules épithéliales, et vise à caractériser les interactions pouvant s’établir d’une part entre ces protéines et épithélium oral, et d‘autre part entre ces protéines et les molécules de ...

Ion temperature via laser scattering on ion Bernstein waves

International Nuclear Information System (INIS)

Wurden, G.A.; Ono, M.; Wong, K.L.

1981-10-01

Hydrogen ion temperature has been measured in a warm toroidal plasma with externally launched ion Bernstein waves detected by heterodyne CO 2 laser scattering. Radial scanning of the laser beam allows precise determination of k/sub perpendicular to/ for the finite ion Larmor radius wave (ω approx. less than or equal to 2Ω/sub i/). Knowledge of the magnetic field strength and ion concentration then give a radially resolved ion temperature from the dispersion relation. Probe measurements and Doppler broadening of ArII 4806A give excellent agreement

Diffuse ions produced by electromagnetic ion beam instabilities

International Nuclear Information System (INIS)

Winske, D.; Leroy, M.M.

1984-01-01

The evolution of the electromagnetic ions beam instability driven by the reflected ion component backstreaming away from the earth's how shock into the foreshock region is studied by means computer simulation. The linear the quasi-linear states of the instability are found to be in good agreement with known results for the resonant model propagating parallel to the beam along the magnetic field and with theory developed in this paper for the nonresonant mode, which propagates antiparallel to the beam direction. The quasi-linear stage, which produces large amplitude 8Bapprox.B, sinusoidal transverse waves and ''intermediate'' ion distribution, is terminated by a nonlinear phase in which strongly nonlinear, compressive waves and ''diffuse'' ion distributions are produced. Additional processes by which the diffuse ions are accelerated to observed high energies are not addressed. The results are discussed in terms of the ion distributions and hydromagnetic waves observed in the foreshock of the earth's bow shock and of interplanetary shocks

Production of highly ionized recoil ions in heavy ion impact

International Nuclear Information System (INIS)

Tawara, H.; Tonuma, T.; Be, S.H.; Shibata, H.; Kase, M.; Kambara, T.; Kumagai, H.; Kohno, I.

1985-01-01

The production mechanisms of highly ionized recoil ions in energetic, highly charged heavy ion impact are compared with those in photon and electron impact. In addition to the innershell ionization processes which are important in photon and electron impact, the electron transfer processes are found to play a key role in heavy ion impact. In molecular targets are also observed highly ionized monoatomic ions which are believed to be produced through production of highly ionized molecular ions followed by prompt dissociation. The observed N 6+ ions produced in 1.05MeV/amu Ar 12+ ions on N 2 molecules are produced through, for example, N 2 12+ *→N 6+ +N 6+ process. (author)

PAPEL DE LA CONFIANZA en las relaciones entre organizaciones

Directory of Open Access Journals (Sweden)

Irene Juana Guillén Mondragón

2006-07-01

Full Text Available El objetivo del presente documento es analizar las definiciones y la importancia de la confianza para crear relaciones de cooperación entre organizaciones de naturaleza distinta. Se hace referencia a los modelos de organización dominantes para acercarnos a los nuevos mecanismos de regulación social propuestos por la sociología para tratar la organización, debido a que en el contexto actual las nuevas concepciones de la organización del trabajo han promovido en las organizaciones formas distintas de competir en el mercado. Procesos de cambio que obligan a las organizaciones a construir una nueva identidad y a renovar los contratos psicológicos con sus integrantes. La noción de confianza ha sido llevada del ámbito social al organizacional con la finalidad de lograr acuerdos entre organizaciones y al mismo tiempo lograr el compromiso de los integrantes de tales entidades. Para que estas puedan funcionar bajo este marco de transformaciones requieren de relaciones de colaboración regidas por la  confianza; relaciones que se dan en los niveles individual, dentro de la organización, entre organizaciones e institucionalmente. Los diferentes niveles de confianza están presentes en las relaciones que entablan los individuos, tanto dentro de la organización como en su entorno. Algunas de las reflexiones en torno a esta problemática nos llevan a pensar que el papel de la confianza es dinámico e incide en la transferencia y el intercambio de conocimientos, técnicas y procedimientos científicos, tecnologías, productos, capitales, entre otros. Además, las relaciones fundadas en la confianza requieren de la suspensión del propio interés, en beneficio de unaorientación colectiva (Mangematin y Thuderoz, 2003. Sin embargo, también se reconoce que con todo y la posibilidad que el hombre tiene de deliberar y de generar confianza, es evidente que entre los hombres prevalecen tanto la confianza calculada como los deseos de altruismo para entrar

Causalidade entre as principais bolsas de valores do mundo

Directory of Open Access Journals (Sweden)

Hiron Pereira Farias

2010-04-01

Full Text Available O objetivo deste trabalho foi analisar os mercados dos países emergentes que fazem parte do Bric, com exceção da Índia, buscando mostrar como os mercados do Brasil, da Rússia e China se comportam entre si e em relação ao mercado dos Estados Unidos. Analisou-se também como alguns países desenvolvidos do grupo G8, Estados Unidos, Reino Unido e Japão, se comportam. Em cada análise, ajustou-se um modelo VAR e buscou-se verificar o grau de dependência dentro e entre cada grupo, utilizando teste de causalidade de Granger, critérios de seleção de modelos, função resposta a impulso e decomposição da variância do erro de previsão. Nas análises realizadas, os mercados brasileiro e americano mostraram forte influência sobre os demais mercados, e, na análise entre os grupos, consideraram-se o mercado dos Estados Unidos do grupo ERJ e todos os mercados emergentes do grupo BRC. O mercado americano mostrou forte influência sobre os outros mercados.

Ion optics in an ion source system

Energy Technology Data Exchange (ETDEWEB)

Abdel-Salam, F W; Moustafa, O A; El-Khabeary, H [Accelerators Dept, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

1997-12-31

An analysis of ion beams from an ion source which consisted of a hemispherical anode, a plane earthed cathode, and a focusing electrode has been carried out. The focal properties of such electrode arrangement were studied using axially symmetric fields. Axial and radial electric fields were obtained as functions of the axial distance. It was found that the radial component of the gradient of potential pushes the ions towards the axis, which indicates the convergent action of the system. The effect of voltage variation between the boundary and the focusing electrode on the position of the plasma boundary are given using the experimental data of the ion source characteristics and its geometrical parameters. The advantages of plasma diffusing outside the source through a small aperture were used by applying a potential to the focusing electrode. It was possible to extract a large ion current from the expanded plasma. The system constituted a lens with a focal length of 29.4 mm. 7 figs.

Heavy ion beams from the new Hungarian ECR ion source

International Nuclear Information System (INIS)

Biri, S.; Valek, A.; Ditroi, F.; Koivisto, H.; Arje, J.; Stiebing, K.; Schmidt, L.

1998-01-01

The first beams of highly charged ions in Hungary were obtained in fall of 1996. The new 14.5 GHz ECR ion source of ATOMKI produced beams of multiply charged ions with remarkable intensities at first experiments. Since then, numerous further developments were carried out. An external electrondonor electrode drastically increased the plasma density and, consequently, the intensity of highly charged ions. These upgrades concentrated mainly on beams from gaseous elements and were carried out by the ECRIS team of ATOMKI. Another series of experiments - ionising from solids - however, was done in the framework of an international collaboration. The first metal ion beam has been extracted from the ECRIS in November 1997 using the known method of Metal Ions from Volatile Compounds (MIVOC). The possibility to put the MIVOC chamber inside the ion source was also tested and the dosing regulation problem of metal vapours inside the ion source was solved. As a result, beams of more than 10 μA of highly charged Fe and Ni ions were produced. (author)

A Study of Ion-Ion Hybrid Instability in the Mixed Plasma

Directory of Open Access Journals (Sweden)

Soo-Yong Kim

1987-12-01

Full Text Available There are more oxygen ions than hydrogen ions in the auroral field zone. We consider both analytic and numerical simulation study of the heating of hydrogen and oxygen ions by auroral electrons. With the low drift speed of electron beams, the ion-ion hybrid wave becomes unstable instead of the lower hybrid wave so that a preferential heating of oxygen ions occurs.

Factores de riesgo que condicionan la conducta machista entre adolescentes.

OpenAIRE

Sánchez Alonso, Isabel

2016-01-01

Este trabajo sobre los factores de riesgo que condicionan la violencia machista entre adolescentes, recoge las principales argumentaciones que explican el origen de la desigualdad entre hombres y mujeres y de cómo la diferencia biológica ha incidido en la división del trabajo según el sexo y en las funciones y roles que debe desempeñar cada uno. A continuación señala los principales factores de riesgo que condicionan la violencia machista en las primeras relaciones am...

Heavy-ion radiography

International Nuclear Information System (INIS)

Fabrikant, J.I.; Tobias, C.A.; Holley, W.R.; Benton, E.V.; Woodruff, K.H.; MacFarland, E.W.

1983-01-01

High energy, heavy-ion beams offer superior discrimination of tissue electron densities at very low radiation doses. This characteristic has potential for diagnostic medical imaging of neoplasms arising in the soft tissues and organs because it can detect smaller inhomogeneities than x rays. Heavy-ion imaging may also increase the accuracy of cancer radiotherapy planning involving use of accelerated charged particles. In the current physics research program of passive heavy-ion imaging, critical modulation transfer function tests are being carried out in heavy-ion projection radiography and heavy-ion computerized tomography. The research goal is to improve the heavy-ion imaging method until it reaches the limits of its theoretical resolution defined by range straggling, multiple scattering, and other factors involved in the beam quality characteristics. Clinical uses of the imaging method include the application of heavy-ion computerized tomography to heavy-ion radiotherapy planning, to the study of brain tumors and other structures of the head, and to low-dose heavy-ion projection mammography, particularly for women with dense breasts where other methods of diagnosis fail. The ions used are primarily 300 to 570 MeV/amu carbon and neon ions accelerated at the Lawrence Berkeley Laboratory Bevalac

Ion channels versus ion pumps: the principal difference, in principle.

Science.gov (United States)

Gadsby, David C

2009-05-01

The incessant traffic of ions across cell membranes is controlled by two kinds of border guards: ion channels and ion pumps. Open channels let selected ions diffuse rapidly down electrical and concentration gradients, whereas ion pumps labour tirelessly to maintain the gradients by consuming energy to slowly move ions thermodynamically uphill. Because of the diametrically opposed tasks and the divergent speeds of channels and pumps, they have traditionally been viewed as completely different entities, as alike as chalk and cheese. But new structural and mechanistic information about both of these classes of molecular machines challenges this comfortable separation and forces its re-evaluation.

Note: Ion source design for ion trap systems

Science.gov (United States)

Noriega, J. R.; Quevedo, M.; Gnade, B.; Vasselli, J.

2013-06-01

A small plasma (glow discharge) based ion source and circuit are described in this work. The ion source works by producing a high voltage pulsed discharge between two electrodes in a pressure range of 50-100 mTorr. A third mesh electrode is used for ion extraction. The electrodes are small stainless steel screws mounted in a MACOR ionization chamber in a linear arrangement. The electrode arrangement is driven by a circuit, design for low power operation. This design is a proof of concept intended for applications on small cylindrical ion traps.

High-ion temperature experiments with negative-ion-based NBI in LHD

International Nuclear Information System (INIS)

Takeiri, Y.; Morita, S.; Tsumori, K.; Ikeda, K.; Oka, Y.; Osakabe, M.; Nagaoka, K.; Goto, M.; Miyazawa, J.; Masuzaki, S.; Ashikawa, N.; Yokoyama, M.; Narihara, K.; Yamada, I.; Kubo, S.; Shimozuma, T.; Inagaki, S.; Tanaka, K.; Peterson, B.J.; Ida, K.; Kaneko, O.; Komori, A.; Murakami, S.

2005-01-01

High-Z plasmas have been produced with Ar- and/or Ne-gas fuelling to increase the ion temperature in the LHD plasmas heated with the high-energy negative-ion-based NBI. Although the electron heating is dominant in the high-energy NBI heating, the direct ion heating power is much enhanced effectively in low-density plasmas due to both an increase in the beam absorption (ionisation) power and a reduction of the ion density in the high-Z plasmas. Intensive Ne- and/or Ar-glow discharge cleaning works well to suppress dilution of the high-Z plasmas with the wall-absorbed hydrogen. As a result, the ion temperature increases with an increase in the ion heating power normalized by the ion density, and reaches 10 keV. An increase in the ion temperature is also observed with an addition of the centrally focused ECRH to the low-density and high-Z NBI plasma, suggesting improvement of the ion transport. The results obtained in the high-Z plasma experiments with the high-energy NBI heating indicate that an increase in the direct ion heating power and improvement of the ion transport are essential to the ion temperature rise, and that a high-ion temperature would be obtained as well in hydrogen plasmas with low-energy positive-NBI heating which is planed in near future in LHD. (author)

Single ion hit detection set-up for the Zagreb ion microprobe

Science.gov (United States)

Smith, R. W.; Karlušić, M.; Jakšić, M.

2012-04-01

Irradiation of materials by heavy ions accelerated in MV tandem accelerators may lead to the production of latent ion tracks in many insulators and semiconductors. If irradiation is performed in a high resolution microprobe facility, ion tracks can be ordered by submicrometer positioning precision. However, full control of the ion track positioning can only be achieved by a reliable ion hit detection system that should provide a trigger signal irrespectively of the type and thickness of the material being irradiated. The most useful process that can be utilised for this purpose is emission of secondary electrons from the sample surface that follows the ion impact. The status report of the set-up presented here is based on the use of a channel electron multiplier (CEM) detector mounted on an interchangable sample holder that is inserted into the chamber in a close geometry along with the sample to be irradiated. The set-up has been tested at the Zagreb ion microprobe for different ions and energies, as well as different geometrical arrangements. For energies of heavy ions below 1 MeV/amu, results show that efficient (100%) control of ion impact can be achieved only for ions heavier than silicon. The successful use of the set-up is demonstrated by production of ordered single ion tracks in a polycarbonate film and by monitoring fluence during ion microbeam patterning of Foturan glass.

Entre monos y centauros

Directory of Open Access Journals (Sweden)

Serge Gruzinski

2005-02-01

Full Text Available    ¿Qué relación puede existir entre Ovidio, Tiziano y unos tlacuilo indios de la sierra otomí ? ¿Qué tienen en comun  el pintor mas famoso del siglo XVI , el veneciano Tiziano (+ 1576,  un poeta latino del primer siglo despues de Cristo, Publio Ovidio Nasón (-43/17 ,  y unos artistas indígenas anónimos del pueblo otomi de Ixmiquilpan?   Aunque la reunión de estos tres nombres parezca extraña y sorprendente, los hilos que los unen no son nada anecdóticos.  Permiten entender mejor la manera...

Heavy-ion radiography and heavy-ion computed tomography

International Nuclear Information System (INIS)

Fabrikant, J.I.; Holley, W.R.; McFarland, E.W.; Tobias, C.a.

1982-02-01

Heavy-ion projection and CT radiography is being developed into a safe, low-dose, noninvasive radiological procedure that can quantitate and image small density differences in human tissues. The applications to heavy-ion mammography and heavy-ion CT imaging of the brain in clinical patients suggest their potential value in cancer diagnosis

Relación entre la lateralidad y los aprendizajes escolares

Directory of Open Access Journals (Sweden)

M.ª Carmen Mayolas Pi

2010-09-01

Full Text Available Muchos son los autores que relacionan los problemas de aprendizaje de un niño con su lateralidad, achacando a la lateralidad contrariada, cruzada o no definida los problemas en la adquisición, entre otras, de habilidades lecto-escritoras. En el presente trabajo hemos pasado un test de lateralidad a 170 niños de entre 6 y 7 años (primero y segundo de primaria con pruebas de miembro superior, miembro inferior y ojo, así como de discriminación de derecha-izquierda y de orientación espacial. A su vez, los profesores tutores han valorado varios ítems del aprendizaje escolar de los niños, con cuestiones sobre su comprensión lectora, su razonamiento matemático y su atención en clase, entre otras. Según nuestros resultados, los niños con lateralidad homogénea diestra son los que obtienen mejores valoraciones en todos los ítems de aprendizaje con respecto a los homogéneos zurdos, los cruzados y los no confirmados, siendo los pocos casos que tenemos de homogéneos zurdos (un 3% de la muestra los que tienen peores valoraciones. Además, los niños que discriminan entre derecha e izquierda también tienen mejor sus aprendizajes con respecto a los que no lo hacen, así como los que se orientan bien en el espacio con respecto a los que se orientan mal.

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

'eau lourde ont porte sur plusieurs procedes. Chacun a ete examine jusqu'a un stade plus ou moins pousse et finalement les efforts se sont concentres sur les echanges isotopiques Hydrogene Sulfure-Eau, et Ammoniac-Gaz de synthese, apres que l'experience pilote ait montre que la distillation d'hydrogene, bien que technologiquement au point, n'etait pas competitive. Procede d'echange NH{sub 3} - gaz de synthese: les recherches se sont poursuivies et ont abouti a la decision de construire une unite de production associee a une synthese d'ammoniac. Le procede est essentiellement dependant de la source de gaz de synthese; on a en effet ecarte, pour des raisons economiques, la mise en oeuvre d'un echange H{sub 2}O/H{sub 2}, qui pouvait le rendre Independant. Parmi les differents schemas possibles de mise en oeuvre du procede, le choix s'est porte sur le monotherme qui, au prix de quelques problemes technologiques, offrait l'avantage de realiser un grand enrichissement avec un nombre reduit de moyens contacts. Ceux-ci sont actuellement au point, apres des essais pilote a grande echelle. L'experience industrielle originale qui va etre mise en oeuvre permettra de reunir des enseignements fructueux pour des usines de deuxiemes generations, qu'elles reprennent le schema monotherme ou qu'elles adoptent le schema bitherme. Procede d'echange H{sub 2}S - H{sub 2}O Les installations pilote, decrites en 1958, ont permis une etude systematique de la corrosion. On a pu passer a la definition d'avant-projets d'usines independantes, avec les variantes 2 et 3 etages en enrichissement primaire H{sub 2}S - H{sub 2}O, la finition etant confiee a la distillation d'eau, au-dela de la teneur de 10 a 20 p.100 en D{sub 2}O. Differents schemas d'echange de chaleur ont ete examines en detail et on a pu en conclure que le choix, comme celui du decoupage de la cascade, etait finalement fonction des conditions economiques du lieu d'implantation. (auteur)

Study of the processes of ion pairs formation by the method of ion-ion coincidence: I2 and chlorine-containing hydrocarbons

International Nuclear Information System (INIS)

Golovin, A.V.

1991-01-01

A method of ion-ion coincidences was suggested to study the process of ion pairs formation during molecule photoionization. The principle of action of ion-ion coincidence method is based on recording of only the negative and positive ions that formed as a result of a molecule decomposition. The flowsheet of the facility of ion-ion coincidences was presented. The processes of ion pairs formation in iodine, chloroform, propyl-, n-propenyl-, tert.butyl- and benzyl-chlorides were studied. A simple model permitting to evaluate the dependence of quantum yield of ion pair formation on excitation energy was suggested

High current vacuum arc ion source for heavy ion fusion

International Nuclear Information System (INIS)

Qi, N.; Schein, J.; Gensler, S.; Prasad, R.R.; Krishnan, M.; Brown, I.

1999-01-01

Heavy Ion fusion (HIF) is one of the approaches for the controlled thermonuclear power production. A source of heavy ions with charge states 1+ to 2+, in ∼0.5 A current beams with ∼20 micros pulse widths and ∼10 Hz repetition rates are required. Thermionic sources have been the workhorse for the HIF program to date, but suffer from sloe turn-on, heating problems for large areas, are limited to low (contact) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states, in short and long pulse bursts, with low emittance and high beam currents. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications is investigated. An existing ion source at LBNL was modified to produce ∼0.5 A, ∼60 keV Gd (A∼158) ion beams. The experimental effort concentrated on beam noise reduction, pulse-to-pulse reproducibility and achieving low beam emittance at 0.5 A ion current level. Details of the source development will be reported

Interações medicamentosas potenciais entre medicamentos psicotrópicos dispensados

Directory of Open Access Journals (Sweden)

Eloise Balen

Full Text Available RESUMO Objetivo Estimar a frequência e caracterizar as interações medicamentosas potenciais entre fármacos psicotrópicos sujeitos a controle especial pela portaria 344/98 da Agência Nacional de Vigilância Sanitária (Anvisa, os quais foram prescritos e dispensados em uma farmácia pública do Município de Cascavel, Paraná. Métodos Estudo retrospectivo com desenho seccional foi realizado em uma Farmácia Pública Municipal. A amostra foi composta por prescrições de medicamentos sujeitos a controle especial, dispensados entre primeiro de julho a 31 de agosto de 2010. As prescrições retidas na farmácia foram analisadas retrospectivamente e as informações, coletadas. As interações medicamentosas potenciais foram identificadas em 824 prescrições. Resultados As prescrições eram na maioria para pacientes do sexo feminino e com idade entre 19 e 59 anos. Em relação à especialidade do prescritor, 30,6% foram prescritas por psiquiatra. Em 77,9% das prescrições identificou-se pelo menos uma interação medicamentosa potencial. Foram descritas 54 diferentes interações medicamentosas potenciais, sendo 34 graves e 20 moderadas. Encontrou-se uma correlação linear entre medicamentos prescritos e interações medicamentosas potenciais (p valor < 0,001. Conclusão O presente estudo identificou uma alta frequência de interações medicamentosas potenciais envolvendo fármacos de controle especial e uma associação positiva entre o número de fármacos prescritos com a maior frequência dessas interações.

Sinergias entre Luxemburgo, ACNUR y Skype

OpenAIRE

Bertout, Antoine; Bourcy, Marc de; Faisal, Mohammad

2011-01-01

Una reciente asociación estratégica entre ACNUR, el Gobierno de Luxemburgo y el proveedor de software para comunicaciones Skype permite al personal de ACNUR en zonas de condiciones de vida difíciles mantenerse en contacto con sus familiares y amigos. Los socios evalúan de qué forma podría adaptarse la tecnología para otras organizaciones humanitarias.

Cs+ ion source for secondary ion mass spectrometry

International Nuclear Information System (INIS)

Bentz, B.L.; Weiss, H.; Liebl, H.

1981-12-01

Various types of cesium ionization sources currently used in secondary ion mass spectrometry are briefly reviewed, followed by a description of the design and performance of a novel, thermal surface ionization Cs + source developed in this laboratory. The source was evaluated for secondary ion mass spectrometry applications using the COALA ion microprobe mass analyzer. (orig.)

Continuidade entre estética e investigação na teoria da arte deweyana: a educação entre arte e ciência, valor e método, ou entre o ideal e o real

OpenAIRE

Ana Daniele de Godoy Dorsa

2013-01-01

A presente pesquisa, de natureza teórico-filosófica, argumenta descritivamente a teoria estética do filósofo americano John Dewey, em função do seu chamado \\"princípio de continuidade\\", próprio do sistema filosófico deweyano como um todo. Nessa empreitada, privilegiou-se o recorte da continuidade entre o estético e o científico, ou entre valor e investigação enquanto característica essencial de tal teoria estética. Na observação dos pressupostos filosóficos gerais do filósofo, verificou-se q...

Las relaciones entre España y Japón

OpenAIRE

Jensana, Amadeo

2013-01-01

Si bien España y Japón son dos países separados por más de 10.000 kilómetros existe una importante afinidad cultural entre ambos pueblos. Los japoneses admiran muchas de las manifestaciones culturales españolas, entre las que destacan la arquitectura (especialmente el Modernismo catalán), el flamenco, la gastronomía o el deporte (hay numerosos seguidores de la Liga Profesional de Fútbol). Por su parte, los españoles son plenamente conscientes del nivel tecnológico de las grandes corporacio...

ESCREVER ENTRE AS LÍNGUAS: TRADUÇÃO E GÊNERO EM NANCY HUSTON

OpenAIRE

WILHELM, Jane Elisabeth; COSTA, Pâmela Berton; DEÂNGELI, Maria Angélica

2017-01-01

O entre duas línguas da auto-tradução em Nancy Huston subverte as relações hierárquicas entre o original e a tradução, ou a oposição entre língua materna e língua estrangeira, e nos convida assim a nos interrogarmos sobre nossas práticas e representações de escrita e de tradução. Buscamos compreender em que medida a escrita entre o francês e o inglês de Nancy Huston questiona não somente as categorias tradicionais de tradução, mas também o gênero como construção social. A história da tradução...

Entre-sons, entre-mundos, entre-idades: ações dialógicas, cultura adolescente e educação musical

OpenAIRE

Vertamatti, Leila Rosa Gonçalves [UNESP

2012-01-01

O presente trabalho tem como ponto central a reflexão a respeito da prática da Educação Musical de jovens entre 11 e 14 anos, do Colégio São José de São Bernardo do Campo, a partir de uma proposta que dialogue com o universo do adolescente, a invenção, a percepção do ambiente acústico, visual, social e cultural e o contexto escolar. A principal questão da investigação é a discussão de processos de elaboração de ações musicais com base em um conceito de prática que leve em conta a distância ex...

From heavy nuclei to super-heavy nuclei; Des noyaux lourds aux super-lourds

Energy Technology Data Exchange (ETDEWEB)

Theisen, Ch

2003-01-01

The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

CERN Document Server

March, Raymond E

2009-01-01

Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

Laser ion sources

Energy Technology Data Exchange (ETDEWEB)

Bykovskij, Yu

1979-02-01

The characteristics a laser source of multiply-ionized ions are described with regard to the interaction of laser radiation and matter, ion energy spectrum, angular ion distribution. The amount of multiple-ionization ions is evaluated. Out of laser source applications a laser injector of multiple-ionization ions and nuclei, laser mass spectrometry, laser X-ray microradiography, and a laser neutron generators are described.

Compact RF ion source for industrial electrostatic ion accelerator

Energy Technology Data Exchange (ETDEWEB)

Kwon, Hyeok-Jung, E-mail: hjkwon@kaeri.re.kr; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub [Korea Multi-purpose Accelerator Complex, Korea Atomic Energy Research Institute, Gyeongsangbukdo 38180 (Korea, Republic of)

2016-02-15

Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

Compact RF ion source for industrial electrostatic ion accelerator

Science.gov (United States)

Kwon, Hyeok-Jung; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub

2016-02-01

Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

Programmable ion mobility spectrometer: Time resolution improvement and ion counter comparison

International Nuclear Information System (INIS)

Harrison, R.G.; Wilding, R.J.

2005-01-01

Atmospheric ion mobility spectrometers operating on the aspirated electrode principle require switching of a bias voltage to select ions of different mobility. The ion spectrum can be obtained by sweeping across a set of bias voltages. If rapid temporal changes in atmospheric ion spectra are to be measured, however, such as for a balloon-carried instrument, the sweep time across the ion spectrum must be kept short. As bias voltage steps can generate saturation in the mobility spectrometer's electrometer amplifier, the electrometer recovery time limits the ion mobility spectrum sweep rate. Here, active compensation of the charge injected at a bias voltage step is used to reduce the saturation time. Further, the optimal setting of the charge compensation circuitry provides a determination of the system capacitance, a necessary calibration parameter for absolute measurements. Using laboratory air, hourly variations in ion concentrations and air conductivity found using the voltage switching system were similar to those obtained with a traditional ion counter operating at a single mobility: ion growth, however, could only be detected using the ion spectrometer

Responsabilidad extracontractual y contractual: barrera entre ambas

Directory of Open Access Journals (Sweden)

González Hernández, Rut

2013-01-01

Full Text Available La finalidad que persigue el sistema de responsabilidad civiles el resarcimiento del daño causado con independencia de que proceda la responsabilidad contractual o la extracontractual, coexistiendo ambas en nuestro ordenamiento jurídico y resultando en ocasiones complicado discernir la frontera entre una y otra.

Development of ion-acoustic double layers through ion-acoustic fluctuations

International Nuclear Information System (INIS)

Sekar, A.N.; Saxena, Y.C.

1985-01-01

Experimental results on the formation of ion acoustic double layers resembling asymmetric ion-holes are presented. In a double plasma device, modified suitably to inject electron beam into the target plasma, modulation of the beam through step potential leads to excitation of ion-acoustic fluctuation. The ion-acoustic fluctuation, growing away from the grids separating source and target plasmas, developed into weak asymmetric ion-acoustic double layer. The observations are in qualitative agreement with theoretical models and computer simulations. (author)

A laser ablation ion source for the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Rink, Ann-Kathrin; Ebert, Jens; Petrick, Martin; Reiter, Pascal [Justus Liebig Universitaet Giessen (Germany); Dickel, Timo; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [Justus Liebig Universitaet Giessen (Germany); GSI, Darmstadt (Germany); Purushothamen, Sivaji [GSI, Darmstadt (Germany)

2013-07-01

The FRS Ion Catcher was developed to serve as test bench for the low energy branch of the Super FRS to slow down exotic nuclei and prepare them for further measurements/ experiments. It consists of a cryogenic stopping cell to thermalise the ions, a diagnostic unit for stopping cell characterisation and various radiofrequency quadrupole structures to guide the ions to the Multiple-Reflection Time-of-Flight Mass Spectrometer for mass measurements, α spectroscopy and isobar separation. To characterise the extraction times of the stopping cell, which is one of the main performance parameters of such a cell, a laser ablation ion source has been develped and tested. This ion source provides a sharply defined starting point of the ions for the extraction time measurement. In the future this source will provide reference ions to calibrate the mass spectrometer for accurate mass measurements.

Ions and light

CERN Document Server

Bowers, Michael T

2013-01-01

Gas Phase Ion Chemistry, Volume 3: Ions and Light discusses how ions are formed by electron impact, ion-molecule reactions, or electrical discharge. This book discusses the use of light emitted by excited molecules to characterize either the chemistry that formed the excited ion, the structure of the excited ion, or both.Organized into 10 chapters, this volume begins with an overview of the extension of the classical flowing afterglow technique to include infrared and chemiluminescence and laser-induced fluorescence detection. This text then examines the experiments involving molecules that ar

Heavy Ion Injection Into Synchrotrons, Based On Electron String Ion Sources

CERN Document Server

Donets, E E; Syresin, E M

2004-01-01

A possibility of heavy ions injection into synchrotrons is discussed on the base of two novel ion sources, which are under development JINR during last decade: 1) the electron string ion source (ESIS), which is a modified version of a conventional electron beam ion source (EBIS), working in a reflex mode of operation, and 2) the tubular electron string ion source (TESIS). The Electron String Ion Source "Krion-2" (VBLHE, JINR, Dubna) with an applied confining magnetic field of 3 T was used for injection into the superconducting JINR synchrotron - Nuclotron and during this runs the source provided a high pulse intensity of the highly charged ion beams: Ar16+

Influence of nonelectrostatic ion-ion interactions on double-layer capacitance

Science.gov (United States)

Zhao, Hui

2012-11-01

Recently a Poisson-Helmholtz-Boltzmann (PHB) model [Bohinc , Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.031130 85, 031130 (2012)] was developed by accounting for solvent-mediated nonelectrostatic ion-ion interactions. Nonelectrostatic interactions are described by a Yukawa-like pair potential. In the present work, we modify the PHB model by adding steric effects (finite ion size) into the free energy to derive governing equations. The modified PHB model is capable of capturing both ion specificity and ion crowding. This modified model is then employed to study the capacitance of the double layer. More specifically, we focus on the influence of nonelectrostatic ion-ion interactions on charging a double layer near a flat surface in the presence of steric effects. We numerically compute the differential capacitance as a function of the voltage under various conditions. At small voltages and low salt concentrations (dilute solution), we find out that the predictions from the modified PHB model are the same as those from the classical Poisson-Boltzmann theory, indicating that nonelectrostatic ion-ion interactions and steric effects are negligible. At moderate voltages, nonelectrostatic ion-ion interactions play an important role in determining the differential capacitance. Generally speaking, nonelectrostatic interactions decrease the capacitance because of additional nonelectrostatic repulsion among excess counterions inside the double layer. However, increasing the voltage gradually favors steric effects, which induce a condensed layer with crowding of counterions near the electrode. Accordingly, the predictions from the modified PHB model collapse onto those computed by the modified Poisson-Boltzmann theory considering steric effects alone. Finally, theoretical predictions are compared and favorably agree with experimental data, in particular, in concentrated solutions, leading one to conclude that the modified PHB model adequately predicts the diffuse

Ion beam modification of solids ion-solid interaction and radiation damage

CERN Document Server

Wesch, Werner

2016-01-01

This book presents the method of ion beam modification of solids in realization, theory and applications in a comprehensive way. It provides a review of the physical basics of ion-solid interaction and on ion-beam induced structural modifications of solids. Ion beams are widely used to modify the physical properties of materials. A complete theory of ion stopping in matter and the calculation of the energy loss due to nuclear and electronic interactions are presented including the effect of ion channeling. To explain structural modifications due to high electronic excitations, different concepts are presented with special emphasis on the thermal spike model. Furthermore, general concepts of damage evolution as a function of ion mass, ion fluence, ion flux and temperature are described in detail and their limits and applicability are discussed. The effect of nuclear and electronic energy loss on structural modifications of solids such as damage formation, phase transitions and amorphization is reviewed for ins...

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)

A Study on the Ion Beam Extraction using Duo-PiGatron Ion source for Vertical Type Ion Beam Facility

Energy Technology Data Exchange (ETDEWEB)

Kim, Bom Sok; Lee, Chan young; Lee, Jae Sang [KAERI, Daejeon (Korea, Republic of)

2015-05-15

In Korea Multipurpose Accelerator Complex (KOMAC), we have started ion beam service in the new beam utilization building since March this year. For various ion beam irradiation services, we are developed implanters such as metal (150keV/1mA), gaseous (200keV/5mA) and high current ion beam facility (20keV/150mA). One of the new one is a vertical type ion beam facility without acceleration tube (60keV/20mA) which is easy to install the sample. After the installation is complete, it is where you are studying the optimal ion beam extraction process. Detailed experimental results will be presented. Vertical Type Ion Beam Facility without acceleration tube of 60keV 20mA class was installed. We successfully extracted 60keV 20mA using Duo- PiGatron Ion source for Vertical Type Ion Beam Facility. Use the BPM and Faraday-cup, is being studied the optimum conditions of ion beam extraction.

Reactions of atomic oxygen with the chlorate ion and the perchlorate ion

Science.gov (United States)

Anan'ev, Vladimir; Miklin, Mikhail; Kriger, Ludmila

2014-06-01

The reactions of the chlorate ion with atomic oxygen formed under photolysis of the nitrate ion introduced to potassium chlorate crystal by co-crystallization were studied by optical and infrared absorption spectroscopy. The perchlorate ion was found to form in solids as product of addition reaction of singlet atomic oxygen, formed under dissociation of the peroxynitrite ion - the product of isomerization of the excited nitrate ion. Triplet atomic oxygen does not react with the chlorate ion. The atomic oxygen formed under photolysis of the nitrate ion introduced to potassium perchlorate crystal by co-crystallization does not react with the perchlorate ion.

Ion species stratification within strong shocks in two-ion plasmas

Science.gov (United States)

Keenan, Brett D.; Simakov, Andrei N.; Taitano, William T.; Chacón, Luis

2018-03-01

Strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al., Phys. Rev. E 96, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by the Mach number, M. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification and temperature separation). These are important effects since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likely contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with the arbitrary Mach number and the relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Additionally, we find that the shock fronts are enriched with the lighter ion species and the enrichment scales as M4 for M ≫ 1.

Electron string ion sources for carbon ion cancer therapy accelerators

Science.gov (United States)

Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Katagiri, K.; Noda, K.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B.

2015-08-01

The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C4+ and C6+ ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 1010 C4+ ions per pulse and about 5 × 109 C6+ ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 1011 C6+ ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the 11C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C4+ ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of 11C, transporting to the tumor with the primary accelerated 11C4+ beam, this efficiency is preliminarily considered to be large enough to produce the 11C4+ beam from radioactive methane and to inject this beam into synchrotrons.

La Vocación entre los Aspirantes a Maestro

Directory of Open Access Journals (Sweden)

Encarnación Sánchez Lissen

2003-01-01

Full Text Available El contenido que ofrecemos en este artículo hace referencia a la dimensión vocacional de los aspirantes a maestro. Tradicionalmente, la enseñanza se ha considerado como una profesión genuinamente vocacional; una circunstancia que, sin embargo, no siempre le ha favorecido. En estos momentos, a pesar de las dificultades que rodean la tarea docente, existe un alto número de estudian-tes que optan por la enseñanza y acceden a las Escuelas de Magisterio. Real-mente, nos podríamos preguntar si el docente -nace o se hace- vocacional hacia esta actividad profesional. Aportamos para ello, los datos de una investigación realizada entre estu-diantes de la Universidad de Sevilla, donde se viene a demostrar por un lado que, muchos eligieron la carrera sin tener un verdadero interés por ella; y por otro, que las Escuelas de Magisterio son en muchos casos, un motor esencial para llegar a despertar o, a descubrir entre los estudiantes, su verdadero interés e inclinación por la enseñanza. Posiblemente, desarrollar actitudes vocaciona-les entre tos aspirantes a maestro es, también, una labor implícita de la Forma-ción Inicial de Maestros

Preliminary Tests of a Paul ion Trap as an Ion Source

Science.gov (United States)

Sadat Kiai, S. M.; Zirak, A. R.; Elahi, M.; Adlparvar, S.; Mortazavi, B. N.; Safarien, A.; Farhangi, S.; Sheibani, S.; Alhooie, S.; Khalaj, M. M. A.; Dabirzadeh, A. A.; Ruzbehani, M.; Zahedi, F.

2010-10-01

The paper reports on the design and construction of a Paul ion trap as an ion source by using an impact electron ionization technique. Ions are produced in the trap and confined for the specific time which is then extracted and detected by a Faraday cup. Especial electronic configurations are employed between the end caps, ring electrodes, electron gun and a negative voltage for the detector. This configuration allows a constant low level of pure ion source between the pulsed confined ion sources. The present experimental results are based on the production and confinement of Argon ions with good stability and repeatability, but in principle, the technique can be used for various Argon like ions.

GANIL Workshop on Ion Sources; Journees Sources d'Ions

Energy Technology Data Exchange (ETDEWEB)

Leroy, Renan [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)

1999-07-01

The proceedings of the GANIL Workshop on Ion Sources held at GANIL - Caen on 18-19 March 1999 contains 13 papers aiming at improving the old source operation and developing new types of sources for nuclear research and studies of ion physics. A number of reports are devoted to applications like surface treatment, ion implantation or fusion injection. The 1+{yields}n+ transformation, charged particle transport in ECR sources, addition of cesium and xenon in negative ion sources and other basic issues in ion sources are also addressed.

Review on heavy ion radiotherapy facilities and related ion sources (invited)

International Nuclear Information System (INIS)

Kitagawa, A.; Fujita, T.; Muramatsu, M.; Biri, S.; Drentje, A. G.

2010-01-01

Heavy ion radiotherapy awakens worldwide interest recently. The clinical results obtained by the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan have clearly demonstrated the advantages of carbon ion radiotherapy. Presently, there are four facilities for heavy ion radiotherapy in operation, and several new facilities are under construction or being planned. The most common requests for ion sources are a long lifetime and good stability and reproducibility. Sufficient intensity has been achieved by electron cyclotron resonance ion sources at the present facilities.

Quantitative ion implantation

International Nuclear Information System (INIS)

Gries, W.H.

1976-06-01

This is a report of the study of the implantation of heavy ions at medium keV-energies into electrically conducting mono-elemental solids, at ion doses too small to cause significant loss of the implanted ions by resputtering. The study has been undertaken to investigate the possibility of accurate portioning of matter in submicrogram quantities, with some specific applications in mind. The problem is extensively investigated both on a theoretical level and in practice. A mathematical model is developed for calculating the loss of implanted ions by resputtering as a function of the implanted ion dose and the sputtering yield. Numerical data are produced therefrom which permit a good order-of-magnitude estimate of the loss for any ion/solid combination in which the ions are heavier than the solid atoms, and for any ion energy from 10 to 300 keV. The implanted ion dose is measured by integration of the ion beam current, and equipment and techniques are described which make possible the accurate integration of an ion current in an electromagnetic isotope separator. The methods are applied to two sample cases, one being a stable isotope, the other a radioisotope. In both cases independent methods are used to show that the implantation is indeed quantitative, as predicted. At the same time the sample cases are used to demonstrate two possible applications for quantitative ion implantation, viz. firstly for the manufacture of calibration standards for instrumental micromethods of elemental trace analysis in metals, and secondly for the determination of the half-lives of long-lived radioisotopes by a specific activity method. It is concluded that the present study has advanced quantitative ion implantation to the state where it can be successfully applied to the solution of problems in other fields

RELACIÓN ENTRE CONDUCTA PARENTAL Y ADHERENCIA AL TRATAMIENTO EN DIABETES INFANTIL.

Directory of Open Access Journals (Sweden)

Rochy Vargas

2008-07-01

Full Text Available En este artículo, enmarcado en la psicología de la salud, se pretende identificar la relación que existe entre la conducta parental y la adherencia al tratamiento a partir de un diseño no-experimental de tipo transversal descriptivo correlacional, en una muestra de niños con diabetes tipo I, entre 8 y 11 años de edad, con un tiempo desde el diagnóstico de entre uno y tres años. Los resultados analizados señalan la relación que existe entre los comportamientos que engloba la variable de conducta parental y adherencia al tratamiento, pudiendo incluso diferenciar aquellos comportamientos más representativos para cada categoría; así por ejemplo, se encontró que la comunicaciónafectiva es el comportamiento parental que más está correlacionado con las conductas de adhesión. Con respecto a las conductas de adhesión al tratamiento, la dieta fue la conducta de este tipo que más se correlacionó con comportamientos parentales.

Ion-acoustic nonlinear periodic waves in electron-positron-ion plasma

International Nuclear Information System (INIS)

Chawla, J. K.; Mishra, M. K.

2010-01-01

Ion-acoustic nonlinear periodic waves, namely, ion-acoustic cnoidal waves have been studied in electron-positron-ion plasma. Using reductive perturbation method and appropriate boundary condition for nonlinear periodic waves, the Korteweg-de Vries (KdV) equation is derived for the system. The cnoidal wave solution of the KdV equation is discussed in detail. It is found that the frequency of the cnoidal wave is a function of its amplitude. It is also found that the positron concentration modifies the properties of the ion-acoustic cnoidal waves. The existence regions for ion-acoustic cnoidal wave in the parameters space (p,σ), where p and σ are the positron concentration and temperature ratio of electron to positron, are discussed in detail. In the limiting case these ion-acoustic cnoidal waves reduce to the ion-acoustic soliton solutions. The effect of other parameters on the characteristics of the nonlinear periodic waves is also discussed.

Dos años entre los indios

Directory of Open Access Journals (Sweden)

Ardila Ardila Olga Felisa

1996-06-01

Full Text Available

La obra constituye la traducción del alemán publicada originalmente en dos volúmenes por E. Wasmuth en Berlín en 1909. En 1967 la Akademische Druck-u Verlagsanstalt en Graz (Austria publicó la segunda edición de la obra original, sobre la cual se trabajó la presente versión en español. La traducción estuvo a cargo de la antropóloga María Mercedes Ortiz. Koch-Grünberg se dedicó al estudio de la filología clásica pero con el tiempo se fue interesando cada vez más por el estudio de los pueblos autóctonos de Suramérica. En 1903 realizó su primera expedición a partir del noroeste brasilero hasta Colombia, en la región comprendida entre el alto río Negro y el Yapurá, área muy poco explorada hasta el momento. La obra Dos años entre los indios resume los resultados básicos de esta expedición. El autor alemán presenta el relato de sus cuatro viajes e ilustra con un mapa la ruta de su expedición a partir del Amazonas. Además del noroeste brasilero, el autor recorre un área importante del territorio colombiano, especialmente la zona del actual departamento del Vaupés. El libro está escrito en forma de un diario de viaje en el que se destacan sus observaciones etnográficas y lingüísticas, especialmente en lo que respecta a la cultura material, el ritual, el arte, las diferentes lenguas nativas habladas en la región y las relaciones de afinidad existentes entre dichas lenguas.

Nanostructures by ion beams

Science.gov (United States)

Schmidt, B.

Ion beam techniques, including conventional broad beam ion implantation, ion beam synthesis and ion irradiation of thin layers, as well as local ion implantation with fine-focused ion beams have been applied in different fields of micro- and nanotechnology. The ion beam synthesis of nanoparticles in high-dose ion-implanted solids is explained as phase separation of nanostructures from a super-saturated solid state through precipitation and Ostwald ripening during subsequent thermal treatment of the ion-implanted samples. A special topic will be addressed to self-organization processes of nanoparticles during ion irradiation of flat and curved solid-state interfaces. As an example of silicon nanocrystal application, the fabrication of silicon nanocrystal non-volatile memories will be described. Finally, the fabrication possibilities of nanostructures, such as nanowires and chains of nanoparticles (e.g. CoSi2), by ion beam synthesis using a focused Co+ ion beam will be demonstrated and possible applications will be mentioned.

Alinhamento estratégico entre empresas fabricantes de equipamentos e alimentos

Directory of Open Access Journals (Sweden)

Roberto Giro Moori

2009-08-01

Full Text Available Este trabalho tem por objetivo verificar o alinhamento das prioridades competitivas entre empresas compradoras e usuárias de máquinas e equipamentos para a fabricação de produtos alimentícios e seus fornecedores industriais. Está fundamentado em uma pesquisa exploratória descritiva em que se aplicou um questionário estruturado junto a gestores das áreas relacionadas a compras, vendas e produção das empresas. Foram obtidas 77 respostas de gestores de empresas fabricantes de alimentos e 55 de fabricantes de equipamentos. Os dados, submetidos à estatística descritiva e à correlação bivariada não paramétrica, revelaram que: a no âmbito do relacionamento entre compradores e vendedores de máquinas e equipamentos, o fator qualidade foi a prioridade competitiva alinhada entre eles; b no âmbito de empresas usuárias de máquinas e equipamentos, houve evidência de trade-off entre as variáveis reduzir estoques e velocidade de entrega rápida. Essas revelações permitiram concluir que: a a qualidade é um fator de alinhamento externo e interno; b o trade-off é usado como um instrumento para o alinhamento das prioridades competitivas no ambiente interno das empresas compradoras e usuárias de máquinas e equipamentos.

Sympathetic cooling of ions in a hybrid atom ion trap

Energy Technology Data Exchange (ETDEWEB)

Hoeltkemeier, Bastian

2016-10-27

In this thesis the dynamics of a trapped ion immersed in a spatially localized buffer gas is investigated. For a homogeneous buffer gas, the ion's energy distribution reaches a stable equilibrium only if the mass of the buffer gas atoms is below a critical value. This limitation can be overcome by using multipole traps in combination and/or a spatially confined buffer gas. Using a generalized model for elastic collisions of the ion with the buffer gas atoms, the ion's energy distribution is numerically determined for arbitrary buffer gas distributions and trap parameters. Three regimes characterized by the respective analytic form of the ion's equilibrium energy distribution are found. One of these is a novel regime at large atom-to-ion mass ratios where the final ion temperature can tuned by adiabatically decreasing the spatial extension of the buffer gas and the effective ion trap depth (forced sympathetic cooling). The second part of the thesis presents a hybrid atom ion trap designed for sympathetic cooling of hydroxide anions. In this hybrid trap the anions are immersed in a cloud of laser cooled rubidium atoms. The translational and rovibrational temperatures of the anions is probed by photodetachment tomography and spectroscopy which shows the first ever indication of sympathetic cooling of anions by laser cooled atoms.

Electron string ion sources for carbon ion cancer therapy accelerators

Energy Technology Data Exchange (ETDEWEB)

Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Katagiri, K.; Noda, K. [National Institute of Radiological Science, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2015-08-15

The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C{sup 4+} and C{sup 6+} ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 10{sup 10} C{sup 4+} ions per pulse and about 5 × 10{sup 9} C{sup 6+} ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 10{sup 11} C{sup 6+} ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the {sup 11}C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C{sup 4+} ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of {sup 11}C, transporting to the tumor with the primary accelerated {sup 11}C{sup 4+} beam, this efficiency is preliminarily considered to be large enough to produce the {sup 11}C{sup 4+} beam from radioactive methane and to inject this beam into synchrotrons.

Emission of positive oxygen ions from ion bombardment of adsorbate-covered metal surfaces

International Nuclear Information System (INIS)

Kaurin, M.G.

1989-01-01

During ion bombardment of metal surfaces, collision cascades can result in the emission of sputtered secondary ions. Recent experiments, however, have suggested that the emission of positive ions of electronegative adsorbates can result from electronic processes rather than from processes involving elastic collisions. This dissertation presents the results of experiments studying the emission of positive oxygen ions from oxygen- and carbon-monoxide-covered transition metal surfaces during bombardment by 25-250 keV ions of neon, argon, and krypton. The systems studied may be grouped into four categories. For a nickel substrate with adsorbed oxygen, the emission of positive oxygen ions proceeds through collision cascades. For titanium and niobium with adsorbed oxygen, the emission of positive oxygen ions is proportional to the primary ion velocity, consistent with emission from electronic processes; for a given primary ion velocity, the oxygen ion yield is independent of primary ion species. For substrates of molybdenum and tungsten, the oxygen yield is proportional to primary ion velocity, but the yield also depends on the primary ion species for a given primary ion velocity in a manner that is consistent with emission resulting from electronic processes. For these two groups, except for titanium, the yields during neon ion bombardment do not extrapolate (assuming linearity with primary ion velocity) to a nonzero value at zero beam velocity. The magnitude of the oxygen ion yields from these targets is not consistent with that expected if the emission were induced by secondary electrons emitted during the ion bombardment

Systems and Methods for Ejection of Ions from an Ion Trap

Science.gov (United States)

Cooks, Robert Graham (Inventor); Snyder, Dalton (Inventor)

2018-01-01

The invention generally relates to systems and methods for ejection of ions from an ion trap. In certain embodiments, systems and methods of the invention sum two different frequency signals into a single summed signal that is applied to an ion trap. In other embodiments, an amplitude of a single frequency signal is modulated as the single frequency signal is being applied to the ion trap. In other embodiments, a first alternating current (AC) signal is applied to an ion trap that varies as a function of time, while a constant radio frequency (RF) signal is applied to the ion trap.

Soutien aux collaborations entre pairs de l'Initiative Think tank et du ...

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

L'Initiative Think tank (ITT) et le Think Tank Fund (TTF) s'associent pour soutenir des collaborations entre pairs entre les think tanks établis dans les régions où oeuvrent l'ITT (Afrique, Amérique latine et Asie du Sud) et le TTF (Europe centrale, Europe de l'Est et ancienne Union soviétique). Ce soutien a pour objectif de ...

Ion Beam Propulsion Study

Science.gov (United States)

2008-01-01

The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

"Cy Twombly: Intérprete de dos mundos" [Un artista entre Estados Unidos y Europa, entre lo clásico y lo contemporáneo

OpenAIRE

Gras Cruz, Irene

2017-01-01

Esta tesis “Cy Twombly: Intérprete de dos mundos” [Un artista entre Estados Unidos y Europa, entre lo clásico y lo contemporáneo] pretende dar a conocer al artista norteamericano Cy Twombly (1928-2011) en nuestro país y destacar la importancia que tiene dentro del panorama artístico como figura clave en un momento de efervescencia —artística y creativa— americana en el que a diferencia de sus coetáneos prefirió emigrar a Europa, concretamente a Italia. Mientras todos se trasladaban a la nueva...

Electron-ion correlation effects in ion-atom single ionization

Energy Technology Data Exchange (ETDEWEB)

Colavecchia, F.D.; Garibotti, C.R. [Centro Atomico Bariloche and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8400 San Carlos de Bariloche (Argentina); Gasaneo, G. [Departamento de Fisica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

2000-06-28

We study the effect of electron-ion correlation in single ionization processes of atoms by ion impact. We present a distorted wave model where the final state is represented by a correlated function solution of a non-separable three-body continuum Hamiltonian, that includes electron-ion correlation as coupling terms of the wave equation. A comparison of the electronic differential cross sections computed with this model with other theories and experimental data reveals that the influence of the electron-ion correlation is more significant for low energy emitted electrons. (author). Letter-to-the-editor.

A quadrupole ion trap as low-energy cluster ion beam source

CERN Document Server

Uchida, N; Kanayama, T

2003-01-01

Kinetic energy distribution of ion beams was measured by a retarding field energy analyzer for a mass-selective cluster ion beam deposition system that uses a quadrupole ion trap as a cluster ion beam source. The results indicated that the system delivers a cluster-ion beam with energy distribution of approx 2 eV, which corresponded well to the calculation results of the trapping potentials in the ion trap. Using this deposition system, mass-selected hydrogenated Si cluster ions Si sub n H sub x sup + were actually deposited on Si(111)-(7x7) surfaces at impact kinetic energy E sub d of 3-30 eV. Observation by using a scanning tunneling microscope (STM) demonstrated that Si sub 6 H sub x sup + cluster ions landed on the surface without decomposition at E sub d =3 eV, while the deposition was destructive at E sub d>=18 eV. (author)

Ion beam enhancement in magnetically insulated ion diodes for high-intensity pulsed ion beam generation in non-relativistic mode

Energy Technology Data Exchange (ETDEWEB)

Zhu, X. P. [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Zhang, Z. C.; Lei, M. K., E-mail: surfeng@dlut.edu.cn [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Pushkarev, A. I. [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Laboratory of Beam and Plasma Technology, High Technologies Physics Institute, Tomsk Polytechnic University, 30, Lenin Ave, 634050 Tomsk (Russian Federation)

2016-01-15

High-intensity pulsed ion beam (HIPIB) with ion current density above Child-Langmuir limit is achieved by extracting ion beam from anode plasma of ion diodes with suppressing electron flow under magnetic field insulation. It was theoretically estimated that with increasing the magnetic field, a maximal value of ion current density may reach nearly 3 times that of Child-Langmuir limit in a non-relativistic mode and close to 6 times in a highly relativistic mode. In this study, the behavior of ion beam enhancement by magnetic insulation is systematically investigated in three types of magnetically insulated ion diodes (MIDs) with passive anode, taking into account the anode plasma generation process on the anode surface. A maximal enhancement factor higher than 6 over the Child-Langmuir limit can be obtained in the non-relativistic mode with accelerating voltage of 200–300 kV. The MIDs differ in two anode plasma formation mechanisms, i.e., surface flashover of a dielectric coating on the anode and explosive emission of electrons from the anode, as well as in two insulation modes of external-magnetic field and self-magnetic field with either non-closed or closed drift of electrons in the anode-cathode (A-K) gap, respectively. Combined with ion current density measurement, energy density characterization is employed to resolve the spatial distribution of energy density before focusing for exploring the ion beam generation process. Consistent results are obtained on three types of MIDs concerning control of neutralizing electron flows for the space charge of ions where the high ion beam enhancement is determined by effective electron neutralization in the A-K gap, while the HIPIB composition of different ion species downstream from the diode may be considerably affected by the ion beam neutralization during propagation.

Recharging of a screened ion on the molecular ion

International Nuclear Information System (INIS)

Karbovanets, M.I.; Lazur, V.Yu.; Yudin, G.L.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Obninsk. Fiziko-Ehnergeticheskij Inst.)

1987-01-01

Charge exchange of a screened ion on a molecular ion is studied in the Oppenheimer-Brinkman-Cramers approximation. To calculate ion exchange probabilities and cross sections summed over the final degenerated electron states method of Green functions analogous to that applied earlier in the direct Coulomb excitation theory and atomic ionization is developed

Acciones y habilidades. Algunas discrepancias entre psicólogos y didactas

Directory of Open Access Journals (Sweden)

Carlos Ezequiel Pino-Pupo

2012-01-01

Full Text Available Abordó puntos de vista discrepantes entre representantes de algunas escuelas de Psicología y de Didáctica cubanas. Durante varios años de investigación en torno a la problemática de la formación de habilidades, se han encontrado posiciones teóricas, muy variadas y son diversos los criterios acerca de la movilidad entre las acciones y las operaciones y en torno a la automatización de unas u otras. Se analiza la equivalencia entre términos de la Didáctica, la Psicología y la Metodología con una propuesta nueva. La intencionalidad del artículo radica en que a partir de las posiciones teóricas asumidas, puede haber una reconsideración de términos utilizados como son los casos de la acción, la operación, la habilidad y el hábito.

Negative Ion Density Fronts

International Nuclear Information System (INIS)

Igor Kaganovich

2000-01-01

Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

entre la pirámide y el axolotl

Directory of Open Access Journals (Sweden)

Paula Andrea Marín Colorado

2006-01-01

Full Text Available En este artículo se presenta un acercamiento a la novela Materia dispuesta, del escritor mexicano Juan Villoro. En esta aproximación analítica se pretende dilucidar la conexión entre la obra literaria y el medio en el que se gesta, así como con el momento histórico recreado en la anécdota de la novela (el terremoto ocurrido en Ciudad de México en 1985; lo anterior con el objetivo de establecer la propuesta estética del autor en esta obra y su relación con la visión que construye Materia dispuesta sobre los procesos de Modernidad y Postmodernidad en Latinoamérica. Para tal propósito se recurrirá a las investigaciones literarias y sociológicas de Mijail Bajtín, Zigmunt Bauman, Carlos Monsiváis y Octavio Paz, entre otros.

Multiply charged ions from solid substances with the mVINIS Ion Source

International Nuclear Information System (INIS)

Dragani, I; Nedeljkovi, T; Jovovi, J; Siljegovic, M; Dobrosavljevic, A

2007-01-01

We have used the well known metal-ions-from-volatile-compounds (MIVOC) method at the mVINIS Ion Source to produce the multiply charged ion beams form solid substances. Based on this method the very intense and stable multiply charged ion beams of several solid substances having the high melting points were extracted. The ion yields and the spectra of multiply charged ion beams obtained from solid materials like Fe and Hf will be presented. We have utilized the multiply charged ion beams from solid substances to irradiate the polymers, fullerenes and glassy carbon at the low energy channel for modification of materials

Ion Selectivity Mechanism in a Bacterial Pentameric Ligand-Gated Ion Channel

International Nuclear Information System (INIS)

Wang, Hailong; Cheng, Xiaolin

2011-01-01

The proton-gated ion channel from Gloeobacter violaceus (GLIC) is a prokaryotic homolog of the eukaryotic nicotinic acetylcholine receptor (nAChR) that responds to the binding of neurotransmitter acetylcholine and mediates fast signal transmission. Recent emergence of a high resolution crystal structure of GLIC captured in a potentially open state allowed detailed, atomic-level insight into ion conduction and selectivity mechanisms in these channels. Herein, we have examined the barriers to ion conduction and origins of ion selectivity in the GLIC channel by the construction of potential of mean force (PMF) profiles for sodium and chloride ions inside the transmembrane region. Our calculations reveal that the GLIC channel is open for a sodium ion to transport, but presents a ∼10 kcal/mol free energy barrier for a chloride ion, which arises primarily from the unfavorable interactions with a ring of negatively charged glutamate residues (E-2) at the intracellular end and a ring of hydrophobic residues (I9) in the middle of the transmembrane domain. Our collective findings further suggest that the charge selection mechanism can, to a large extent, be attributed to the narrow intracellular end and a ring of glutamate residues in this position their strong negative electrostatics and ability to bind cations. By contrast, E19 at the extracellular entrance only plays a minor role in ion selectivity of GLIC. In addition to electrostatics, both ion hydration and protein dynamics are found to be crucial for ion conduction as well, which explains why a chloride ion experiences a much greater barrier than a sodium ion in the hydrophobic region of the pore.

Partition/Ion-Exclusion Chromatographic Ion Stacking for the Analysis of Trace Anions in Water and Salt Samples by Ion Chromatography.

Science.gov (United States)

Akter, Fouzia; Saito, Shingo; Tasaki-Handa, Yuiko; Shibukawa, Masami

2018-01-01

A new analytical methodology for a simple and efficient on-line preconcentration of trace inorganic anions in water and salt samples prior to ion chromatographic determination is proposed. The preconcentration method is based on partition/ion-exclusion chromatographic ion stacking (PIEC ion stacking) with a hydrophilic polymer gel column containing a small amount of fixed anionic charges. The developed on-line PIEC ion stacking-ion chromatography method was validated by recovery experiments for the determination of nitrate in tap water in terms of both accuracy and precision, and the results showed the reliability of the method. The method proposed was also successfully applied to the determination of trace impurity nitrite and nitrate in reagent-grade salts of sodium sulfate. A low background level can be achieved since pure water is used as the eluant for the PIEC ion stacking. It is possible to reach sensitive detection at sub-μg L -1 levels by on-line PIEC ion stacking-ion chromatography.

Development of a compact ECR ion source for various ion production

Energy Technology Data Exchange (ETDEWEB)

Muramatsu, M., E-mail: m-mura@nirs.go.jp; Hojo, S.; Iwata, Y.; Katagiri, K.; Sakamoto, Y.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Takahashi, N. [Sumitomo Heavy Industries, Ltd., 19 Natsushima, Yokosuka, Kanagawa 237-8555 (Japan); Sasaki, N.; Fukushima, K.; Takahashi, K.; Suzuki, T.; Sasano, T. [Accelerator Engineering Corporation, 3-8-5 Konakadai, Inage, Chiba 263-0043 (Japan); Uchida, T.; Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama 350-8585 (Japan); Hagino, S.; Nishiokada, T.; Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

2016-02-15

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Molecular dynamics simulations of ion range profiles for heavy ions in light targets

Energy Technology Data Exchange (ETDEWEB)

Lan, C. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 (China); Xue, J.M. [State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 (China); Zhang, Y., E-mail: Zhangy1@ornl.gov [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Morris, J.R. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhu, Z. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Gao, Y.; Wang, Y.G.; Yan, S. [State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 (China); Weber, W.J. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2012-09-01

The determination of stopping powers for slow heavy ions in targets containing light elements is important to accurately describe ion-solid interactions, evaluate ion irradiation effects and predict ion ranges for device fabrication and nuclear applications. Recently, discrepancies of up to 40% between the experimental results and SRIM (Stopping and Range of Ions in Matter) predictions of ion ranges for heavy ions with medium and low energies (<{approx}25 keV/nucleon) in light elemental targets have been reported. The longer experimental ion ranges indicate that the stopping powers used in the SRIM code are overestimated. Here, a molecular dynamics simulation scheme is developed to calculate the ion ranges of heavy ions in light elemental targets. Electronic stopping powers generated from both a reciprocity approach and the SRIM code are used to investigate the influence of electronic stopping on ion range profiles. The ion range profiles for Au and Pb ions in SiC and Er ions in Si, with energies between 20 and 5250 keV, are simulated. The simulation results show that the depth profiles of implanted ions are deeper and in better agreement with the experiments when using the electronic stopping power values derived from the reciprocity approach. These results indicate that the origin of the discrepancy in ion ranges between experimental results and SRIM predictions in the low energy region may be an overestimation of the electronic stopping powers used in SRIM.

Ion implantation

International Nuclear Information System (INIS)

Johnson, E.

1986-01-01

It is the purpose of the present paper to give a review of surface alloy processing by ion implantation. However, rather than covering this vast subject as a whole, the survey is confined to a presentation of the microstructures that can be found in metal surfaces after ion implantation. The presentation is limited to alloys processed by ion implantation proper, that is to processes in which the alloy compositions are altered significantly by direct injection of the implanted ions. The review is introduced by a presentation of the processes taking place during development of the fundamental event in ion implantation - the collision cascade, followed by a summary of the various microstructures which can be formed after ion implantation into metals. This is compared with the variability of microstructures that can be achieved by rapid solidification processing. The microstructures are subsequently discussed in the light of the processes which, as the implantations proceed, take place during and immediately after formation of the individual collision cascades. These collision cascades define the volumes inside which individual ions are slowed down in the implanted targets. They are not only centres for vigorous agitation but also the sources for formation of excess concentrations of point defects, which will influence development of particular microstructures. A final section presents a selection of specific structures which have been observed in different alloy systems. (orig./GSCH)

Transport of negative hydrogen and deuterium ions in RF-driven ion sources

International Nuclear Information System (INIS)

Gutser, R; Wuenderlich, D; Fantz, U

2010-01-01

Negative hydrogen ion sources are major components of neutral beam injection systems for plasma heating in future large-scale fusion experiments such as ITER. In order to fulfill the requirements of the ITER neutral beam injection, a high-performance, large-area RF-driven ion source for negative ions is being developed at the MPI fuer Plasmaphysik. Negative hydrogen ions are mainly generated on a converter surface by impinging neutral particles and positive ions under the influence of magnetic fields and the plasma sheath potential. The 3D transport code TrajAn has been applied in order to obtain the total and spatially resolved extraction probabilities for H - and D - ions under identical plasma parameters and the realistic magnetic field topology of the ion source. A comparison of the isotopes shows a lower total extraction probability in the case of deuterium ions, caused by a different transport effect. The transport calculation shows that distortions of the spatial distributions of ion birth and extraction by the magnetic electron suppression field are present for both negative hydrogen and deuterium ions.

Análisis de materiales con haces de iones generados por un acelerador electrostático

Directory of Open Access Journals (Sweden)

Climent Font, A.

2000-08-01

Full Text Available An electrostatic accelerator is a very versatile tool for the analysis of the materials elemental composition by means of ion beam based analytical techniques. These techniques known as IBA (ion beam analysis are widely used as a quantitative and non destructive characterization of almost any material down to depth of 10 μm below the surface and with a surface resolution from 2 to 20 nm. Their applications cover a wide range of areas such as: materials science, microelectronics, environmental studies, biomedical sciences, art and archaeology, etc. In this work the general physical principles of IBA are reviewed and its capabilities are illustrated with a selection of examples.

Un acelerador electrostático es una herramienta muy versátil para analizar materiales mediante las técnicas de haces de iones. Estas técnicas, conocidas como técnicas IBA (ion beam analysis, son ampliamente utilizadas para la caracterización cuantitativa y no destructiva de la estructura y la composición de la zona próxima a la superficie de cualquier material, hasta profundidades de 10 μm y con resolución superficial de 2 a 20 nm. Sus aplicaciones abarcan muchos campos, entre los que destacan: ciencia de materiales, microelectrónica, metalurgia, mineralogía, estudios medioambientales, ciencias biomédicas, arte y arqueología, etc. En este trabajo se revisan los principios físicos de las técnicas IBA y algunas de sus capacidades analíticas se ilustran con una selección de ejemplos.

Tandem Mass Spectrometry and Ion Mobility Reveals Structural Insight into Eicosanoid Product Ion Formation.

Science.gov (United States)

Di Giovanni, James P; Barkley, Robert M; Jones, David N M; Hankin, Joseph A; Murphy, Robert C

2018-04-23

Ion mobility measurements of product ions were used to characterize the collisional cross section (CCS) of various complex lipid [M-H] - ions using traveling wave ion mobility mass spectrometry (TWIMS). TWIMS analysis of various product ions derived after collisional activation of mono- and dihydroxy arachidonate metabolites was found to be more complex than the analysis of intact molecular ions and provided some insight into molecular mechanisms involved in product ion formation. The CCS observed for the molecular ion [M-H] - and certain product ions were consistent with a folded ion structure, the latter predicted by the proposed mechanisms of product ion formation. Unexpectedly, product ions from [M-H-H 2 O-CO 2 ] - and [M-H-H 2 O] - displayed complex ion mobility profiles suggesting multiple mechanisms of ion formation. The [M-H-H 2 O] - ion from LTB 4 was studied in more detail using both nitrogen and helium as the drift gas in the ion mobility cell. One population of [M-H-H 2 O] - product ions from LTB 4 was consistent with formation of covalent ring structures, while the ions displaying a higher CCS were consistent with a more open-chain structure. Using molecular dynamics and theoretical CCS calculations, energy minimized structures of those product ions with the open-chain structures were found to have a higher CCS than a folded molecular ion structure. The measurement of product ion mobility can be an additional and unique signature of eicosanoids measured by LC-MS/MS techniques. Graphical Abstract ᅟ.

Tandem Mass Spectrometry and Ion Mobility Reveals Structural Insight into Eicosanoid Product Ion Formation

Science.gov (United States)

Di Giovanni, James P.; Barkley, Robert M.; Jones, David N. M.; Hankin, Joseph A.; Murphy, Robert C.

2018-04-01

Ion mobility measurements of product ions were used to characterize the collisional cross section (CCS) of various complex lipid [M-H]- ions using traveling wave ion mobility mass spectrometry (TWIMS). TWIMS analysis of various product ions derived after collisional activation of mono- and dihydroxy arachidonate metabolites was found to be more complex than the analysis of intact molecular ions and provided some insight into molecular mechanisms involved in product ion formation. The CCS observed for the molecular ion [M-H]- and certain product ions were consistent with a folded ion structure, the latter predicted by the proposed mechanisms of product ion formation. Unexpectedly, product ions from [M-H-H2O-CO2]- and [M-H-H2O]- displayed complex ion mobility profiles suggesting multiple mechanisms of ion formation. The [M-H-H2O]- ion from LTB4 was studied in more detail using both nitrogen and helium as the drift gas in the ion mobility cell. One population of [M-H-H2O]- product ions from LTB4 was consistent with formation of covalent ring structures, while the ions displaying a higher CCS were consistent with a more open-chain structure. Using molecular dynamics and theoretical CCS calculations, energy minimized structures of those product ions with the open-chain structures were found to have a higher CCS than a folded molecular ion structure. The measurement of product ion mobility can be an additional and unique signature of eicosanoids measured by LC-MS/MS techniques. [Figure not available: see fulltext.

An electron cyclotron resonance ion source based low energy ion beam platform

International Nuclear Information System (INIS)

Sun, L. T.; Shang, Y.; Ma, B. H.; Zhang, X. Z.; Feng, Y. C.; Li, X. X.; Wang, H.; Guo, X. H.; Song, M. T.; Zhao, H. Y.; Zhang, Z. M.; Zhao, H. W.; Xie, D. Z.

2008-01-01

To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed

An electron cyclotron resonance ion source based low energy ion beam platform.

Science.gov (United States)

Sun, L T; Shang, Y; Ma, B H; Zhang, X Z; Feng, Y C; Li, X X; Wang, H; Guo, X H; Song, M T; Zhao, H Y; Zhang, Z M; Zhao, H W; Xie, D Z

2008-02-01

To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed.

Ion-beam plasma and propagation of intense compensated ion beams

Energy Technology Data Exchange (ETDEWEB)

Gabovich, M D [AN Ukrainskoj SSR, Kiev. Inst. Fiziki

1977-02-01

Discussed are the results of investigation of plasma properties received by neutralization of intense ion beam space charge. Considered is the process of ion beam compensation by charges, formed as a result of gas ionization by this beam or by externally introduced ones. Emphasis is placed on collective phenomena in ion-beam plasma, in particular on non-linear effects limiting amplitude of oscillations. It is shown that not only dynamic decompensation but the Coulomb collisions of ions with electrons as well as other collective oscillations significantly affects the propagation of compensated ion beams. All the processes are to be taken into account in solving the problem of obtaining ''superdense'' compensated beams.

Ion-beam plasma and propagation of intense compensated ion beams

International Nuclear Information System (INIS)

Gabovich, M.D.

1977-01-01

Discussed are the results of investigation of plasma properties recieved by neutralization of intensive ion beam space charge. Considered is the process of ion beam compensation by charges, formed as a result of gas ionization by this beam or by externally introduced ones. Emphasis is placed on collective phenomena in ion-beam plasma, in particular on non-linear effects limiting amplitude of oscillations. It is shown, that not only dinamic decompensation but the Coulomb collisions of ions with electrons as well as other collective oscillations significantly affects the propagation of compensated ion beams. All the processes are to be taken into account at solving the problem of obtaining ''superdense'' compensated beams

Spiral 2 cryogenic system overview: Design, construction and performance test

Energy Technology Data Exchange (ETDEWEB)

Deschildre, C.; Bernhardt, J.; Flavien, G.; Crispel, S. [Air Liquide Advanced Technologies, Sassenage (France); Souli, M. [GANIL, Caen (France); Commeaux, C. [IPN, Orsay (France)

2014-01-29

The new particle accelerator project Spiral 2 at GANIL (“Grand Accélérateur d’Ions Lourds, i.e. National Large Heavy Ion Accelerator) in Caen (France) is a very large installation, intended to serve fundamental research in nuclear physics. The heart of the future machine features a superconductor linear accelerator, delivering a beam until 20Mev/A, which are then used to bombard a matter target. The resulting reactions, such as fission, transfer, fusion, etc. will generate billions of exotic nuclei. To achieve acceleration of the beam, 26 cavities which are placed inside cryomodules at helium cryogenic temperature will be used. AL-AT (Air Liquide Advanced Technologies) takes part to the project by supplying cryogenic plant. The plant includes the liquefier associated to its compressor station, a large dewar, a storage tank for helium gas and transfer lines. In addition, a helium recovery system composed of recovery compressor, high pressure storage and external purifier has been supplied. Customized HELIAL LF has been designed, manufactured and tested by AL-AT to match the refrigeration power need for the Spiral 2 project which is around 1300 W equivalent at 4.5 K.

Ion source techniques for high-speed processing of material surface by ion beams

International Nuclear Information System (INIS)

Ishikawa, Junzo

1990-01-01

The present paper discusses some key or candidate techniques for future ion source development and such ion sources developed by the author. Several types of microwave ion sources for producing low charge state ions have been developed in Japan. When a microwave plasma cathode developed by the author is adapted to a Kaufman type ion source, the electron emission currents are found to be 2.5 A for argon gas and 0.5-0.9 A for oxygen gas. An alternative ionization method for metal atoms is strongly required for high-speed processing of material surface by metal-ion beams. Detailed discussion is made of collisional ionization of vaporized atoms, and negative-ion production (secondary negative-ion emission by sputtering). An impregnated electrode type liquid-metal ion source developed by the author, which has a porous tip structure, is described. The negative-ion production efficiency is quite high. The report also presents a neutral and ionized alkaline-metal bombardment type heavy negative-ion source, which consists of a cesium plasma ion source, suppressor, target electrode, negative-ion extraction electrode, and einzel lens. (N.K.)

Fundamental processes determining the highly charged ion production in ECR ion sources

International Nuclear Information System (INIS)

Shirkov, G.D.

1992-01-01

The ion confinement and loss conditions in the open magnetic traps have been analyzed in this article. In EGRIS the the ions are confined in the negative potential well. The simultaneous application of ion cooling and pulse regime is proposed for pulse injection of highly charged ions in heavy ion accelerators and storage rings. 14 refs.; 3 figs

Jet measurements in ATLAS Detector for making evident the deconfinement in heavy ion collisions; Mesure des jets dans le detecteur ATLAS en vue de la mise en evidence du deconfinement dans les collisions d`ions lourds

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-13

In this thesis the two kinds of works encountered in the preparation of a big experiment at LHC are considered: R and D on the optimization of the light collection from the hadronic tile calorimeter of ATLAS, using new photomultipliers (PM), and physical simulations of the search for nuclear matter deconfinement in heavy ion collisions. The interest of using LHC is to obtain thermodynamical conditions better than those offered for the present or future experiments, by the SPS and RHIC accelerators, respectively. ATLAS is a general purpose p-p experiment that offers the additional possibility of studying the behaviour of heavy quarkonia and jets as deconfinement external probes, in terms of the global variables characterizing the collision geometry and thermodynamics. The definition of a proper strategy for ATLAS requires a comparison with the other experiments (ALICE and CMS) at LHC. It is shown that the search of the jet quenching at a reduced luminosity is the most promising approach for ATLAS. The experiment is described, and in particular the hadronic tile calorimeter, especially designed for the jet studies. The produced light is readout by a new PM the optimisation of which is described in order to design the PM blocks containing the light mixing, the PM itself, the divider bridge and associated electronics. Special attention is paid to the PM gains, the optimisation of the light guides and magnetic shielding. That is retained by ATLAS as the base line solution. (author) 68 refs.

Projecte d'integració entre SAP GH - SAP MM - Kàrdex

OpenAIRE

Perea Núñez, Yolanda

2012-01-01

Projecte d'integració entre dos sistemes SAP (gestió hospitalària i gestió de materials) amb un altre sistema aliè a SAP, el sistema de magatzem de medicaments Kàrdex, mitjançant comunicacions via SAP Process Integration. Proyecto de integración entre dos sistemas SAP (gestión hospitalaria y gestión de materiales) con otro sistema ajeno a SAP, el sistema de almacén de medicamentos Kardex, mediante comunicaciones vía SAP Process Integration.

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1983-01-01

Ion-Selective Electrode Reviews, Volume 5 is a collection of articles that covers ion-speciation. The book aims to present the advancements of the range and capabilities of selective ion-sensors. The topics covered in the selection are neutral carrier based ion-selective electrodes; reference electrodes and liquid junction effects in ion-selective electrode potentiometry; ion transfer across water/organic phase boundaries and analytical; and carbon substrate ion-selective electrodes. The text will be of great use to chemists and chemical engineers.

Electron Beam Ion Sources

CERN Document Server

Zschornacka, G.; Thorn, A.

2013-12-16

Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

ECR ion source based low energy ion beam facility

Indian Academy of Sciences (India)

Mass analyzed highly charged ion beams of energy ranging from a few keV to a few MeV plays an important role in various aspects of research in modern physics. In this paper a unique low energy ion beam facility (LEIBF) set up at Nuclear Science Centre (NSC) for providing low and medium energy multiply charged ion ...

Containment for Heavy-Water Gas-Cooled Reactors; Le Confinement des Reacteurs a Eau Lourde Refroidis par Gaz

Energy Technology Data Exchange (ETDEWEB)

Verstraete, P.; Lehmann, D.; Lafitte, R. [Bonard et Gardel, Ingenieurs-Conseils, Lausanne (Switzerland)

1967-09-15

The safety principles applicable to heavy-water, gas-cooled reactors are outlined, with a view to establishing containment specifications adapted to the sites available in Switzerland for the construction of nuclear plants. These specifications are derived from dose rates considered acceptable, in the event of a serious reactor accident, for persons living near the plant, and are based on-meteorological and demographic conditions representative of the majority of the country's sites. The authors consider various designs for the containment shell, taking into account the conditions which would exist in the shell after the maximum credible accident. The following types of shell are studied: pre-stressed concrete; pre-stressed concrete with steel dome; pre-stressed concrete with inner, leakproof steel lining; steel with concrete side shield to protect against radiation; double shell. The degree of leak proofing of the shells studied is regarded as a feature of the particular design and not as a fixed constructional specification. The authors assess the leak proofing properties of each type of shell and establish building costs for each of them on the basis of precise plans, with the collaboration of various specialized firms. They estimate the effectiveness of the various shells from a safety standpoint, in relation to different emergency procedures, in particular release into the atmosphere through appropriate filters and decontamination of the air within the shell by recycling through batteries of filters. The paper contains a very detailed comparison of about 10 cases corresponding to various combinations of design and emergency procedure; the comparison was made using a computer programme specially established for the purpose. The results are compared with those for a reactor of the same type and power, but assembled together with the heat exchangers in a pre-stressed concrete shell. (author) [French] Les principes de securite des reacteurs a eau lourde refroidis

Factores socioculturales y consumo de drogas entre estudiantes universitarios costarricenses

Directory of Open Access Journals (Sweden)

Jaime Alonso Caravaca Morera

2015-01-01

Full Text Available Investigación cuantitativa de tipo descriptiva-exploratoria, con diseño transversal que examinó el efecto moderador de ciertos factores socio-culturales en el consumo de drogas entre estudiantes universitarios en San José, Costa Rica. La muestra fue conformada por 126 mujeres y 124 hombres de una universidad pública de forma no probabilística. Fue elaborado un cuestionario con cinco escalas ya validadas, que interrogaba sobre la influencia del grupo de pares, las relaciones familiares, el entretenimiento, la espiritualidad y el consumo de drogas. Se utilizó el programa SPSS versión 18 para el análisis estadístico. Se estableció que el 98,4% de los estudiantes reportaron tener por lo menos un amigo que consumía drogas, las drogas más consumidas fueron alcohol, tabaco y marihuana. Se estableció asociación significativa entre algunos factores académicos y culturales con el consumo de drogas legales e ilegales. Se concluye que deben ser implementadas estrategias preventivas considerando la influencia de los factores culturales entre los estudiantes universitarios.

Improving the Modeling of Hydrogen Solubility in Heavy Oil Cuts Using an Augmented Grayson Streed (AGS Approach Modélisation améliorée de la solubilité de l’hydrogène dans des coupes lourdes par l’approche de Grayson Streed Augmenté (GSA

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Torres R.

2013-04-01

cependant que sa précision se dégrade rapidement pour les coupes lourdes. Une amélioration est proposée dans ce travail, basée sur l’ajout d’un terme de Flory dans le calcul du coefficient d’activité. L’étude de la solubilité de l’hydrogène dans les n-alcanes du n-C7 au n-C36 fait apparaître que la constante de Henry diminue avec la masse molaire. L’analyse de ce comportement suggère la présence d’une déviation entropique à l’idéalité non prise en compte dans le modèle des solutions régulières. L’utilisation d’une correction de Flory permet de garder l’aspect prédictif du modèle. Elle nécessite néanmoins un nouveau calage de certains paramètres de la corrélation d’origine pour l’hydrogène. Le modèle qui résulte se comporte mieux pour les composés lourds et aromatiques. La qualité du nouveau modèle de Grayson Streed Augmenté (GSA est évaluée sur des données de solubilité d’hydrogène dans des coupes pétrolières issues de Cai et al. [Cai H.Y. et al. (2001 Fuel 80, 1055-1063] ainsi que Lin et al. [Lin H.M. et al. (1981 Ind. Eng. Chem. Process Des. Dev. 20, 2, 253-256]. L’importance de la caractérisation de ces coupes est mise en avant. Une analyse de sensibilité montre qu’une perturbation du paramètre de solubilité a un effet beaucoup plus important que pour les autres paramètres. Il en résulte qu’un grand soin doit être apporté au calcul de cette grandeur. La prédiction de la solubilité de l’hydrogène dans des fractions pétrolières lourdes et dans des charbons liquéfiés a été améliorée par rapport au modèle de Grayson Streed : une déviation absolue moyenne de 30 % est obtenue pour GSA, à comparer avec 55 % avec la méthode GS, avec les données utilisées dans un domaine de 80-380 °C et 6,3-258,9 bar.

Ion-acoustic double layers in multi-species plasmas maintained by negative ions

International Nuclear Information System (INIS)

Verheest, F.

1989-01-01

A study is made of ion-acoustic double layers in a plasma consisting of any number of cold positive and negative ion (and cold electron) species in addition to one isothermal electron population. The Sagdeev potential is obtained in general, together with limits on both compressive and rarefactive solutions for ion-acoustic double layers and/or solitons. Weak ion-acoustic double layers are described by a modified Korteweg-de Vries equation. Such double layers are not possible in plasmas with only positive ion species and one electron population. When one or more negative ion and/or cold electron species are included above a certain threshold density, rarefactive ion-acoustic double layers occur, but no compressive ones. The double-layer form of the potential is given, together with an application to a plasma with one positive and one negative ion component. It is shown that there is indeed such a threshold density for the negative ion density, depending on the charge-to-mass ratios of both types of ions. The threshold density is determined numerically for a range of such ratios and discussed in view of possible relevance to auroral and experimental plasmas. In the discussion, cold electrons can play the role of the negative ion species. (author)

Possibility of ion-exchange column studies using stabilised montmorillonite-H aggregates; Possibilite d'etude d'echanges d'ions en colonne sur des agregats de Montmorillonite-H stabilises

Energy Technology Data Exchange (ETDEWEB)

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

1959-07-01

The conditions necessary for obtaining stable aggregates of montmorillonite-H, prepared without addition of organic flocculant, is discussed. These aggregates possess the same general ion-exchange properties as montmorillonite-H suspensions, about which many papers have been written. Their insolubility and their stable physical form enable them to be used in columns in exactly the same way as the usual organic ion exchangers. The examples of cation fixation and separation described in this report emphasize the similarities between the properties of this exchanger and those of organic cation-exchange resins, and open up possibilities for the extrapolation of the many investigations carried out on organic exchangers to mineral exchangers of this type. Amongst the essential differences to be remarked, we have shown that the properties of physical stability and chemical exchange remain the same at temperatures up to 300 deg. C, to a first approximation, under very intense {gamma} irradiation. (author) [French] Les conditions d'obtention d'agregats stables de montmorillonite-H prepares sans addition de floculant organique sont discutees. Ces agregats possedent les proprietes generales d'echangeurs d'ions des suspensions de montmorillonite-H, tres etudiees par de nombreux auteurs. Ils presentent une insolubilite et une forme physique stable permettant une utilisation en colonne identique a celle des echangeurs d'ions organiques usuels. Les exemples de fixation et de separation de cations qui ont ete decrits dans cet expose font ressortir les analogies entre les proprietes de cet echangeur et celles des resines organiques echangeurs de cations et permettent d'esperer une extrapolation aux echangeurs mineraux de ce type des tres nombreux travaux consacres aux echangeurs organiques. Parmi les differences essentielles a noter, nous avons mis en evidence que les proprietes de stabilite physique et d'echanges chimiques des agregats de montmorillonite subsistent a des

An alkali ion source based on graphite intercalation compounds for ion mobility spectrometry

International Nuclear Information System (INIS)

Tabrizchi, Mahmoud; Hosseini, Zahra S

2008-01-01

A variety of alkali cation emitters were developed as the ion source for ion mobility spectrometry. The cation emitters were constructed based on alkali ion graphite intercalation compounds (GICs). The compounds were prepared by fusing alkali salts with ground graphite. In order to produce alkali ions, the compounds were loaded on a filament and heated to red. Reactant ions of the form alk + ions were observed for the alkali salts NaCl, KCl.LiCl, CsCl and SrCl. In addition to Na + ions, K + ions were observed at the beginning of thermionic emission from Na-GIC. This is due to the low ionization potential of potassium that exists in trace amounts in sodium salts. In addition to the potassium ion, Na + was observed in the case of LiCl salt. The Na + and K + peaks originating from impurities totally disappeared after about 40 min. However, the thermionic emission of the main ion of the corresponding salt lasted for several days. No negative ions were observed upon reversing the drift field. Selected organic compounds (methyl isobutyl ketone, dimethyl sulfoxide, acetone and tetrahydrofuran) were also ionized via alkali cation attachment reaction. Distinct ion mobility patterns were observed for different substances using one type of alkali reactant ion. However, the ion mobility pattern for a given substance changed when a different alkali reactant ion was used. Ammonia and amines were not ionized when this source was used

Indústria de tabaco e cidadania: confronto entre redes organizacionais

OpenAIRE

Boeira, Sérgio Luís

2006-01-01

O artigo aborda a história da indústria de tabaco no Brasil e da formação de sua rede estratégica, bem como da rede dos atores sociais que a contrapõem. Na primeira parte, apresenta-se uma correlação entre a história da produção industrial, do consumo de tabaco e do antitabagismo. Na segunda parte são apresentados os conceitos de rede estratégica e de rede multifragmentária (antifumo), propostos para facilitar a compreensão de alguns dos múltiplos aspectos conflitivos entre as duas redes. A p...

Óxidos de estaño: nuevos ánodos para baterías de Ion-Litio

Directory of Open Access Journals (Sweden)

Morales, J.

1999-12-01

Full Text Available The electrochemical reaction between Li and tin-based compounds, is reversible and takes place at low potentials measured against the Li electrode. This feature allows the use of these materials as negative electrodes in the manufacturing of Li-ion batteries. The lithium insertion in the tin oxides leads to the formation of Li-Sn alloys. The presence of large tin clusters, formed during the reaction, causes the cracking and crumblimg of the anodic material and the electronic contact between the particles is lost. The electrochemical performance of these materials can be optimized by controlling the growing and size of tin aggregates.

La reacción entre el litio y óxidos o aleaciones de estaño es reversible cuando se realiza por métodos electroquímicos y a bajos potenciales con respecto al electrodo de litio. Esta propiedad permite el uso de estos materiales como electrodos negativos en el diseño y construcción de baterías tipo ion-litio. En el caso de óxidos de estaño la reacción de inserción de litio en la matriz conduce a la formación de aleaciones Li-Sn. La presencia de agregados grandes de átomos de estaño, formados durante la inserción de litio, origina la fragmentación y el desmoronamiento del material anódico. Este efecto provoca la pérdida del contacto eléctrico entre partículas, con el consiguiente deterioro de la batería. La optimización del rendimiento electroquímico de estos materiales se puede lograr mediante el control del crecimiento y tamaño de los agregados de estaño.

Methods of selection in heavy ion collisions at Fermi energies and de-excitation modes with the INDRA multi-detector; Methodes de tri dans les collisions d'ions lourds aux energies de Fermi et modes de desexcitation avec le multidetecteur INDRA

Energy Technology Data Exchange (ETDEWEB)

Lautesse, Ph

2005-11-15

The progress made in particle detection, particularly the design of multi-detectors, like INDRA, that cover a solid angle of almost 4{pi}, have given a new impetus to heavy ion collisions. These detectors are demanding for an efficient way of selecting events that have a common history or similar features, for instance the events representing the de-excitation of a unique emitter. The problem is to find the adequate variable on which the discrimination can be based. Different methods are proposed in this work, the common point is that they require efficient models to reproduce and analyse experimental data in order to apprehend the equation of state of nuclear matter. Most of these models are based on the numerically solving of the nuclear Boltzmann equation. The application to the Ni + Ni reaction with an energy ranging from a few A.MeV to more than 50 A.MeV illustrates this work. (A.C.)

Methods of selection in heavy ion collisions at Fermi energies and de-excitation modes with the INDRA multi-detector; Methodes de tri dans les collisions d'ions lourds aux energies de Fermi et modes de desexcitation avec le multidetecteur INDRA

Energy Technology Data Exchange (ETDEWEB)

Lautesse, Ph

2005-11-15

The progress made in particle detection, particularly the design of multi-detectors, like INDRA, that cover a solid angle of almost 4{pi}, have given a new impetus to heavy ion collisions. These detectors are demanding for an efficient way of selecting events that have a common history or similar features, for instance the events representing the de-excitation of a unique emitter. The problem is to find the adequate variable on which the discrimination can be based. Different methods are proposed in this work, the common point is that they require efficient models to reproduce and analyse experimental data in order to apprehend the equation of state of nuclear matter. Most of these models are based on the numerically solving of the nuclear Boltzmann equation. The application to the Ni + Ni reaction with an energy ranging from a few A.MeV to more than 50 A.MeV illustrates this work. (A.C.)

FLUJO DE GENES ENTRE FRIJOL COMÚN Y SILVESTRE EN COSTA RICA

Directory of Open Access Journals (Sweden)

N\\u00E9stor Chaves-Barrantes

2009-01-01

Full Text Available Con el objetivo de analizar el flujo de genes entre frijol común silvestre y cultivado, se determinó el porcentaje de alogamia en condiciones naturales de crecimie nto del frijol silvestre y en estación experimental. En el 2004 se evaluó el cruzamie nto natural entre frijol silvestre mexicano G23511A (Phaseolus vulgaris L. y la línea blanca PAN 68, en la Estación Experimental Fabio Baudrit de la Universidad de Costa Ri ca en Alajuela. Para ello se sembraron dos parcelas experimentales; cada una constó de dos bloques de PAN 68 de 10 surcos (15 m de largo y espacia dos 0,6 m. Entre los bloques y en el borde superior de los mismos, se sembraron tres surcos de frijol silvestre como donantes de polen. Se numeraron las hileras y las plantas de cada una en los bloques de frijol blanco. En Quircot de Ca rtago (área donde crece en forma natural P. vulgaris silvestre, en el 2005 y 2006, se sembraron plantas de frijol comercia l (Vainica de Palo a lo largo de seis sitios junto a las poblaciones de frijol silvestre. En ambas localidades la floración de silvestres y comerciales fue coincidente. Se cosechó toda la semilla de los ensayos y se germinó en bandejas, determinando el porcentaje de alogamia por medio del color morado del hip ocotilo, indicativo de aquellas plántulas cruzadas. En Alajuela el porcentaje de cruza varió entre 0,007 y 0,028 %; mie ntras que en Quircot, entre 0 y 0,199 %.

Plasma ion sources and ion beam technology in microfabrications

International Nuclear Information System (INIS)

Ji, Lili

2007-01-01

For over decades, focused ion beam (FIB) has been playing a very important role in microscale technology and research, among which, semiconductor microfabrication is one of its biggest application area. As the dimensions of IC devices are scaled down, it has shown the need for new ion beam tools and new approaches to the fabrication of small-scale devices. In the meanwhile, nanotechnology has also deeply involved in material science research and bioresearch in recent years. The conventional FIB systems which utilize liquid gallium ion sources to achieve nanometer scale resolution can no longer meet the various requirements raised from such a wide application area such as low contamination, high throughput and so on. The drive towards controlling materials properties at nanometer length scales relies on the availability of efficient tools. In this thesis, three novel ion beam tools have been developed and investigated as the alternatives for the conventional FIB systems in some particular applications. An integrated focused ion beam (FIB) and scanning electron microscope (SEM) system has been developed for direct doping or surface modification. This new instrument employs a mini-RF driven plasma source to generate focused ion beam with various ion species, a FEI two-lens electron (2LE) column for SEM imaging, and a five-axis manipulator system for sample positioning. An all-electrostatic two-lens column has been designed to focus the ion beam extracted from the source. Based on the Munro ion optics simulation, beam spot sizes as small as 100 nm can be achieved at beam energies between 5 to 35 keV if a 5 (micro)m-diameter extraction aperture is used. Smaller beam spot sizes can be obtained with smaller apertures at sacrifice of some beam current. The FEI 2LE column, which utilizes Schottky emission, electrostatic focusing optics, and stacked-disk column construction, can provide high-resolution (as small as 20 nm) imaging capability, with fairly long working distance

Gas phase ion chemistry

CERN Document Server

Bowers, Michael T

1979-01-01

Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

Entre a potência e o poder: Walter Benjamin e Roger Caillois

Directory of Open Access Journals (Sweden)

Susana Scramim

2009-01-01

Full Text Available http://dx.doi.org/10.5007/1984-784X.2009v9n14p101 A escrita fragmentária empenhada por Benjamim em "Seqüência em Ibiza" e os aforismos do Oráculo Manual y Arte de Prudencia de Gracián  indicam o esboço de uma reflexão sobre o poder na obra de Benjamin a qual se materializará como limiar entre a forma e o informe, entre a autonomia e auto-implicação, entre a obra e a des-obra. Essa reflexão se torna aguda  no impacto provocado em Benjamin pela a leitura  de L´ariditè que Roger Caillois publica juntamente com outros ensaios, em 1938, no Colégio de Sociologia em Paris.

Design of the compact ECR ion source for heavy-ion therapy

International Nuclear Information System (INIS)

Muramatsu, M.; Kitagawa, A.; Sato, S.; Sato, Y.; Yamada, S.; Hattori, T.; Shibuya, S.

1999-01-01

Heavy ion cancer treatment is successfully being done at the Heavy Ion Medical Accelerator in Chiba (HIMAC). Design philosophy for the ion sources for medical facilities are as follows: sufficient beam intensity, a few hundred eμA; long lifetime with good stability; easy operation and easy maintenance; and compactness. In order to develop such source for future heavy-ion facilities, we have tested compact electron cyclotron resonance (ECR) ion sources using permanent magnets both for axial and radial confinement of hot electrons. Since the yield of C 2+ ion in the firstly-developed source (2.45 GHz ECR) was 15 eμA and far below the medical requirement (-150 eμA for the HIMAC), a new source has been proposed, having the frequency of 10 GHz. The extracted intensity of C 4+ (and C 2+ ) ions is expected to be higher than 200 eμA. (author)

Compression Ratio Ion Mobility Programming (CRIMP) Accumulation and Compression of Billions of Ions for Ion Mobility-Mass Spectrometry Using Traveling Waves in Structures for Lossless Ion Manipulations (SLIM)

Energy Technology Data Exchange (ETDEWEB)

Deng, Liulin; Garimella, Venkata BS; Hamid, Ahmed M.; Webb, Ian K.; Attah, Isaac K.; Norheim, Randolph V.; Prost, Spencer A.; Zheng, Xueyun; Sandoval, Jeremy A.; Baker, Erin M.; Ibrahim, Yehia M.; Smith, Richard D.

2017-05-25

We report on the implementation of a traveling wave (TW) based compression ratio ion mobility programming (CRIMP) approach within Structures for Lossless Ion Manipulations (SLIM) that enables both greatly enlarged trapped ion charge capacities and also their subsequent efficient compression for use in ion mobility (IM) separations. Ion accumulation is conducted in a long serpentine path TW SLIM region after which CRIMP allows the large ion populations to be ‘squeezed’. The compression process occurs at an interface between two SLIM regions, one operating conventionally and the second having an intermittently pausing or ‘stuttering’ TW, allowing the contents of multiple bins of ions from the first region to be merged into a single bin in the second region. In this initial work stationary voltages in the second region were used to block ions from exiting the first (trapping) region, and the resumption of TWs in the second region allows ions to exit, and the population to also be compressed if CRIMP is applied. In our initial evaluation we show that the number of charges trapped for a 40 s accumulation period was ~5×109, more than two orders of magnitude greater than the previously reported charge capacity using an ion funnel trap. We also show that over 1×109 ions can be accumulated with high efficiency in the present device, and that the extent of subsequent compression is only limited by the space charge capacity of the trapping region. Lower compression ratios allow increased IM peak heights without significant loss of signal, while excessively large compression ratios can lead to ion losses and other artifacts. Importantly, we show that extended ion accumulation in conjunction with CRIMP and multiple passes provides the basis for a highly desirable combination of ultra-high sensitivity and ultra-high resolution IM separations using SLIM.

Fast ion-atom and ion-molecule collisions

CERN Document Server

2013-01-01

The principal goal of this book is to provide state-of-the art coverage of the non-relativistic three- and four-body theories at intermediate and high energy ion-atom and ion-molecule collisions. The focus is on the most frequently studied processes: electron capture, ionization, transfer excitation and transfer ionization. The content is suitable both for graduate students and experienced researchers. For these collisions, the literature has seen enormous renewal of activity in the development and applications of quantum-mechanical theories. This subject is of relevance in several branches of science and technology, like accelerator-based physics, the search for new sources of energy and high temperature fusion of light ions. Other important applications are in life sciences via medicine, where high-energy ion beams are used in radiotherapy for which a number of storage ring accelerators are in full operation, under construction or planned to be built worldwide. Therefore, it is necessary to review this fiel...

Ion Concentration- and Voltage-Dependent Push and Pull Mechanisms of Potassium Channel Ion Conduction.

Directory of Open Access Journals (Sweden)

Kota Kasahara

Full Text Available The mechanism of ion conduction by potassium channels is one of the central issues in physiology. In particular, it is still unclear how the ion concentration and the membrane voltage drive ion conduction. We have investigated the dynamics of the ion conduction processes in the Kv1.2 pore domain, by molecular dynamics (MD simulations with several different voltages and ion concentrations. By focusing on the detailed ion movements through the pore including selectivity filter (SF and cavity, we found two major conduction mechanisms, called the III-IV-III and III-II-III mechanisms, and the balance between the ion concentration and the voltage determines the mechanism preference. In the III-IV-III mechanism, the outermost ion in the pore is pushed out by a new ion coming from the intracellular fluid, and four-ion states were transiently observed. In the III-II-III mechanism, the outermost ion is pulled out first, without pushing by incoming ions. Increases in the ion concentration and voltage accelerated ion conductions, but their mechanisms were different. The increase in the ion concentrations facilitated the III-IV-III conductions, while the higher voltages increased the III-II-III conductions, indicating that the pore domain of potassium channels permeates ions by using two different driving forces: a push by intracellular ions and a pull by voltage.

Fast-ion Dα measurements of the fast-ion distribution (invited)

International Nuclear Information System (INIS)

Heidbrink, W. W.

2010-01-01

The fast-ion Dα (FIDA) diagnostic is an application of charge-exchange recombination spectroscopy. Fast ions that neutralize in an injected neutral beam emit Balmer-α light with a large Doppler shift. The spectral shift is exploited to distinguish the FIDA emission from other bright sources of Dα light. Background subtraction is the main technical challenge. A spectroscopic diagnostic typically achieves temporal, energy, and transverse spatial resolution of ∼1 ms, ∼10 keV, and ∼2 cm, respectively. Installations that use narrow-band filters achieve high spatial and temporal resolution at the expense of spectral information. For high temporal resolution, the bandpass-filtered light goes directly to a photomultiplier, allowing detection of ∼50 kHz oscillations in FIDA signal. For two-dimensional spatial profiles, the bandpass-filtered light goes to a charge-coupled device camera; detailed images of fast-ion redistribution at instabilities are obtained. Qualitative and quantitative models relate the measured FIDA signals to the fast-ion distribution function. The first quantitative comparisons between theory and experiment found excellent agreement in beam-heated magnetohydrodynamics (MHD)-quiescent plasmas. FIDA diagnostics are now in operation at magnetic-fusion facilities worldwide. They are used to study fast-ion acceleration by ion cyclotron heating, to detect fast-ion transport by MHD modes and microturbulence, and to study fast-ion driven instabilities.

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.

Invalidez por dor nas costas entre segurados da Previdência Social do Brasil

Directory of Open Access Journals (Sweden)

Ney Meziat Filho

2011-06-01

Full Text Available OBJETIVO: Descrever as aposentadorias por invalidez decorrente de dor nas costas. MÉTODOS: Estudo descritivo com dados do Sistema Único de Informações de Benefícios e dos Anuários Estatísticos da Previdência Social em 2007. A taxa de incidência de dor nas costas como causa das aposentadorias por invalidez foi calculada segundo as variáveis idade e sexo, nos estados. Os dias de trabalho perdidos por invalidez decorrente de dor nas costas foram calculados segundo atividade profissional. RESULTADOS: A dor nas costas idiopática foi a primeira causa de invalidez entre as aposentadorias previdenciárias e acidentárias. A maioria dos beneficiários residia em área urbana e era comerciário. A taxa de incidência de dor nas costas como causa das aposentadorias por invalidez no Brasil foi de 29,96 por 100.000 contribuintes. Esse valor foi mais elevado entre os homens e entre as pessoas mais velhas. Rondônia exibiu taxa quatro vezes superior ao esperado (RT = 4,05 e a segunda maior taxa, referente à Bahia, foi de aproximadamente duas vezes o esperado (RT = 2,07. Os comerciários foram responsáveis por 96,9% dos dias perdidos por invalidez. CONCLUSÕES: A dor nas costas foi uma importante causa de invalidez em 2007, sobretudo entre comerciários, com grandes diferenças entre os estados.

RELACIÓN ENTRE DIFERENTES PRUEBAS DE CAMPO: FUERZA, POTENCIA Y VELOCIDAD

OpenAIRE

Jessenia Hernández Elizondo

2003-01-01

Esta investigación tuvo como propósito principal el encontrar por medio de pruebas en las variables de fuerza, potencia y velocidad, la relación matemática existente entre estos tres constructos. Participaron 56 sujetos varones con edades entre 18 y 25 años. Con el fin de responder al objetivo del estudio, se les aplicaron pruebas de campo de fuerza (1RM de sentadilla completa y repeticiones máximas al 80% 60% 40% y 20%), de velocidad (30 metros lanzados y 30 metros sin impulso), y de potenci...

Rearrangement reactions in ion-ion and ion-atom collisions: results and problems

Energy Technology Data Exchange (ETDEWEB)

Presnyakov, L.P. [Lebedev Physical Institute, Moscow (Russian Federation); Tawara, H.

1997-01-01

Recent experimental and theoretical results are discussed for ionic collisions with large cross sections at intermediate and small energies of the relative motion. Single- and double-electron removal from H{sup -} ions in slow collisions with other ions is considered in more details. The theoretical methods are discussed from the viewpoint of general requirements of scattering theory. (author)

Ion-ion Recombination and Chemiion Concentrations In Aircraft Exhaust

Science.gov (United States)

Turco, R. P.; Yu, F.

Jet aircraft emit large quantities of ultrafine volatile aerosols, as well as soot parti- cles, into the environment. To determine the long-term effects of these emissions, a better understanding of the mechanisms that control particle formation and evolution is needed, including the number and size dispersion. A recent explanation for aerosol nucleation in a jet wake involves the condensation of sulfuric acid vapor, and cer- tain organic compounds, onto charged molecular clusters (chemiions) generated in the engine combustors (Yu and Turco, 1997). Massive charged aggregates, along with sulfuric acid and organic precursor vapors, have been detected in jet plumes under cruise conditions. In developing the chemiion nucleation theory, Yu and Turco noted that ion-ion recombination in the engine train and jet core should limit the chemiion emission index to 1017/kg-fuel. This value is consistent with ion-ion recombination coefficients of 1×10-7 cm3/s over time scales of 10-2 s. However, the evolution of the ions through the engine has not been adequately studied. The conditions at the combustor exit are extreme-temperatures approach 1500 K, and pressures can reach 30 atmospheres. In this presentation, we show that as the combustion gases expand and cool, two- and three-body ion-ion recombination processes control the chemiion concentration. The concepts of mutual neutralization and Thomson recombination are first summarized, and appropriate temperature and pressure dependent recombination rate coefficients are derived for the aircraft problem. A model for ion losses in jet exhaust is then formulated using an "invariance" principle discussed by Turco and Yu (1997) in the context of a coagulating aerosol in an expanding plume. This recombina- tion model is applied to estimate chemiion emission indices for a range of operational engine conditions. The predicted ion emission rates are found to be consistent with observations. We discuss the sources of variance in chemiion

A heavy ion pre-injector for the ICT-ion implanter

International Nuclear Information System (INIS)

Bhattacharya, P.K.; Gaonkar, S.; Wagh, A.G.; Hattangadi, V.A.; Sarma, N.

1976-01-01

A cheap and versatile hollow cathode electron bombardment ion source system including its ion extraction-cum-focussing assembly for obtaining intense heavy ion beams of solids and gases is described. The extractor region is designed to include more than 15deg total beam angle of extracted beam for producing focused ion current densities upto 60mA/cm 2 to serve as a pre-injector for the ICT(insulated core transformer) type ion implanter. The extraction-cum-focussing lens is a low aberration strong Einzel lens system of all araldite and metal construction with optical elements of proper quality and location to suit low voltage injection and subsequent ion analysis. The injection can be selected anywhere between 2 to 10 keV for singly charged ions with typical extraction currents of 500/μ, using a ring anode and a source aperture of 20 mil. Einzel lens focussing assembly allows continuous adjustment of the beam convergence to about 5deg and the beam size to approximately 5mm in diameter with about 10 KV central electrode potential. Test results of source characteristics for both the accelerating and decelerating model of beam formation have been made. (author)

Afetividade entre professor e aluno no processo ensino-aprendizagem

Directory of Open Access Journals (Sweden)

Jéssica Simone Galdino Schaefer

2015-06-01

Full Text Available Este artigo tem como objetivo analisar as relações de afetividade entre professor e aluno no processo ensino-aprendizagem. Utiliza de metodologia com abordagem qualitativa, observação participante, e entrevistas semi-estruturadas. O lócus da pesquisa foi a Escola Municipal de Educação Básica Lizamara Aparecida Oliva de Almeida em Sinop, entre Fevereiro e Maio de 2014. Enquanto sujeitos, contou-se com professores e alunos do 3º ano do Ensino Fundamental. Dos resultados parciais, verificou-se que mesmo que a afetividade e a aprendizagem sejam reconhecidas teoricamente por Henri Wallon como elos fundamentais para o processo ensino-aprendizagem, ainda não é bem compreendido pelos sujeitos professores. Palavras-chave: psicologia educacional; afetividade; professores e alunos. 

Upgraded vacuum arc ion source for metal ion implantation

International Nuclear Information System (INIS)

Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Yushkov, G. Yu.; Brown, I. G.

2012-01-01

Vacuum arc ion sources have been made and used by a large number of research groups around the world over the past twenty years. The first generation of vacuum arc ion sources (dubbed ''Mevva,'' for metal vapor vacuum arc) was developed at Lawrence Berkeley National Laboratory in the 1980s. This paper considers the design, performance parameters, and some applications of a new modified version of this kind of source which we have called Mevva-V.Ru. The source produces broad beams of metal ions at an extraction voltage of up to 60 kV and a time-averaged ion beam current in the milliampere range. Here, we describe the Mevva-V.Ru vacuum arc ion source that we have developed at Tomsk and summarize its beam characteristics along with some of the applications to which we have put it. We also describe the source performance using compound cathodes.

Squeezing of Ion Populations and Peaks in Traveling Wave Ion Mobility Separations and Structures for Lossless Ion Manipulations using Compression Ratio Ion Mobility Programming

Energy Technology Data Exchange (ETDEWEB)

Garimella, Venkata BS; Hamid, Ahmed M.; Deng, Liulin; Ibrahim, Yehia M.; Webb, Ian K.; Baker, Erin M.; Prost, Spencer A.; Norheim, Randolph V.; Anderson, Gordon A.; Smith, Richard D.

2016-11-02

In this work, we report an approach for spatial and temporal gas phase ion population manipulation, and demonstrate its application for the collapse of the ion distributions in ion mobility (IM) separations into tighter packets providing higher sensitivity measurements in conjunction with mass spectrometry (MS). We do this for ions moving from a conventionally traveling wave (TW)-driven region to a region where the TW is intermittently halted or ‘stuttered’. This approach causes the ion packets spanning a number of TW-created traveling traps (TT) to be redistributed into fewer TT, resulting in spatial compression. The degree of spatial compression is controllable and determined by the ratio of stationary time of the TW in the second region to its moving time. This compression ratio ion mobility programming (CRIMP) approach has been implemented using Structures for Lossless Ion Manipulations (SLIM) in conjunction with MS. CRIMP with the SLIM-MS platform is shown to provide increased peak intensities, reduced peak widths, and improved S/N ratios with MS detection. CRIMP also provides a foundation for extremely long path length and multi-pass IM separations in SLIM providing greatly enhanced IM resolution by reducing the detrimental effects of diffusional peak broadening due to increasing peak widths.

Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

Science.gov (United States)

Johnson, Brian J.

2014-01-01

Ion exchange chromatography is an important technique in the separation of charged species, particularly in biological, inorganic, and environmental samples. In this experiment, students are supplied with a mixture of two substitution-inert complex ions. They separate the complexes by ion exchange chromatography using a "flash"…

CONCORDANCIA ENTRE CINCO DEFINICIONES DE SÍNDROME METABÓLICO. CARTAGENA, COLOMBIA

Directory of Open Access Journals (Sweden)

Gustavo Mora García

2012-01-01

Full Text Available Fundamentos: Durante la última década el síndrome metabólico fue definido en cinco diferentes guías. Con cada definición se modifica la capacidad predictiva del síndrome sobre la enfermedad cardiovascular. El objetivo del presente estudio fue determinar el grado de concordancia entre estas cinco guías en Cartagena (Colombia. Métodos: Se realizó un estudio de corte transversal en adultos. El tamaño mínimo de muestra se estimó con información del censo DANE 2005. Se realizó un muestreo por conglomerados bietápico que incluyó 670 individuos. Para estimar la prevalencia del síndrome se aplicaron las guías OMS (Organización Mundial de la Salud, AHA/NHBLI (Asociación Americana del Corazón, ATPIII (Panel de Tratamiento de Adultos, IDF (Federación Internacional de Diabetes y JIS (Declaración Provisional Conjunta. La concordancia fue calculada con el índice Kappa de Cohen. Resultados: Según las guías JIS, IDF, ATPIII, AHA/NHBLI y OMS, la prevalencia de síndrome metabólico fue del 36,3%, 35,1%, 30,3%, 24,2% y 4,9% respectivamente. La concordancia entre JIS e IDF fue de 0,893 mientras que el índice entre estas guías y AHA/NHBLI fue de 0,778 y 0,750 respectivamente. El ATP III tuvo una concordancia más baja con JIS e IDF (0,711 y 0,645, respectivamente pero con AHA/NHLBI la concordancia fue de 0,863. La OMS presentó un acuerdo con las demás guías de entre 0,14 y 0,16. Conclusiones: Existe concordancia significativa entre las cuatro guías más recientes. Los puntos de corte para obesidad abdominal podrían justificar las diferencias encontradas.

Entre la Venadita y la Medusa

Directory of Open Access Journals (Sweden)

Valcárcel, Amelia

2008-06-01

Full Text Available Feminism has made in the last decades relevant advances towards equity between men and women in western societies. However, both mysogyny and gynophobia are still at work, giving as a result a «deflation of expectations» among women who enter the worlds of politics, information, corporations, economic power, knowledge, religion or art, and find a glass ceiling in full operation. The paper focuses on women artists, examines the anger expressed in feminist art as an answer to exclusion, and argues for feminist strategies of analysis and correction of inequalities.

El feminismo ha conseguido en los últimos años importantes avances hacia la igualdad entre hombres y mujeres en las sociedades occidentales. Y, sin embargo, tanto la misoginia como la ginofobia siguen vigentes, provocando una «deflación de expectativas » entre las mujeres que se incorporan a los mundos de la política, la información, las organizaciones empresariales, el poder económico, el saber, la religión o la creatividad, y se topan con el techo de cristal a pleno funcionamiento. El artículo se centra en las mujeres creadoras para examinar la cólera expresada en el arte feminista como respuesta a la exclusión y defender estrategias feministas de análisis y corrección de desigualdades.

Simulation study on ion extraction from ECR ion sources

International Nuclear Information System (INIS)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author)

Simulation study on ion extraction from ECR ion sources

Energy Technology Data Exchange (ETDEWEB)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author).

Heavy ion program at BNL: AGS, RHIC [Relativistic Heavy Ion Collider

International Nuclear Information System (INIS)

Barton, D.S.

1987-01-01

With the recent commissioning of fixed target, heavy ion physics at the AGS, Brookhaven National Laboratory (BNL) has embarked on a long range program in support of relativistic heavy ion research. Acceleration of low mass heavy ions (up to sulfur) to an energy of about 14.5 GeV/nucleon is possible with the direct connection of the BNL Tandem Van de Graaff and AGS accelerators. When completed, the new booster accelerator will provide heavy ions over the full mass range for injection and subsequent acceleration in the AGS. BNL is now engaged in an active R and D program directed toward the proposed Relativistic Heavy Ion Collider (RHIC). The results of the first operation of the low mass heavy ion program will be reviewed, and future expectations discussed. The expected performance for the heavy ion operation of the booster will be described and finally, the current status and outlook for the RHIC facility will be presented

The heavy ion injection scheme for RHIC [Relativistic Heavy Ion Collider

International Nuclear Information System (INIS)

Rhoades-Brown, M.J.

1989-01-01

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven has a multi-component injection system. The Collider requires very heavy ions such as 79 197 Au to be injected fully stripped of atomic electrons, at a kinetic energy of approximately 10 GeV/nucleon. However, the heavy ions are produced initially at a negative ion source and accelerated first in a 15 MV Tandem. These partially stripped ions have a kinetic energy of approximately 1 MeV/nucleon on leaving the Tandem. In order to achieve the injection requirements for RHIC, the partially stripped ions are accelerated in the Booster (currently under construction) and pass through a stripping foil on their way to the Alternating Gradient Synchrotron (AGS), where they are further accelerated before injection into RHIC. Recent theoretical calculations have shown quite convincingly that very heavy ions with 2 electrons in the filled K-shell may be accelerated with negligible loss in the AGS. 13 refs., 3 figs., 3 tabs

Auroral ion beams and ion acoustic wave generation by fan instability

Energy Technology Data Exchange (ETDEWEB)

Vaivads, A

1996-04-01

Satellite observations indicate that efficient energy transport among various plasma particles and between plasma waves and plasma particles is taking place in auroral ion beam regions. These observations show that two characteristic wave types are associated with the auroral ion beam regions: electrostatic hydrogen cyclotron waves with frequencies above hydrogen gyrofrequency, and low frequency waves with frequencies below hydrogen gyrofrequency. We speculate that the low frequency waves can be ion acoustic waves generated through the fan instability. The presence of a cold background ion component is necessary for the onset of this instability. A cold ion component has been directly observed and has been indirectly suggested from observations of solitary wave structures. The wave-particle interaction during the development of the fan instability results in an efficient ion beam heating in the direction perpendicular to the ambient magnetic field. The fan instability development and the ion beam heating is demonstrated in a numerical particle simulation. 23 refs, 16 figs.

Ion Trapping, Storage, and Ejection in Structures for Lossless Ion Manipulations.

Science.gov (United States)

Zhang, Xinyu; Garimella, Sandilya V B; Prost, Spencer A; Webb, Ian K; Chen, Tsung-Chi; Tang, Keqi; Tolmachev, Aleksey V; Norheim, Randolph V; Baker, Erin S; Anderson, Gordon A; Ibrahim, Yehia M; Smith, Richard D

2015-06-16

A new Structures for Lossless Ion Manipulations (SLIM) module, having electrode arrays patterned on a pair of parallel printed circuit boards (PCB), was constructed and utilized to investigate capabilities for ion trapping at a pressure of 4 Torr. Positive ions were confined by application of RF voltages to a series of inner rung electrodes with alternating phase on adjacent electrodes, in conjunction with positive DC potentials on surrounding guard electrodes on each PCB. An axial DC field was also introduced by stepwise varying the DC potentials applied to the inner rung electrodes to control the ion transport and accumulation inside the ion trapping region. We show that ions can be trapped and accumulated with up to 100% efficiency, stored for at least 5 h with no significant losses, and then could be rapidly ejected from the SLIM trap. The present results provide a foundation for the development of much more complex SLIM devices that facilitate extended ion manipulations.

Numerical Simulation of Ion Transport in a Nano-Electrospray Ion Source at Atmospheric Pressure

Science.gov (United States)

Wang, Wei; Bajic, Steve; John, Benzi; Emerson, David R.

2018-03-01

Understanding ion transport properties from the ion source to the mass spectrometer (MS) is essential for optimizing device performance. Numerical simulation helps in understanding of ion transport properties and, furthermore, facilitates instrument design. In contrast to previously reported numerical studies, ion transport simulations in a continuous injection mode whilst considering realistic space-charge effects have been carried out. The flow field was solved using Reynolds-averaged Navier-Stokes (RANS) equations, and a particle-in-cell (PIC) method was applied to solve a time-dependent electric field with local charge density. A series of ion transport simulations were carried out at different cone gas flow rates, ion source currents, and capillary voltages. A force evaluation analysis reveals that the electric force, the drag force, and the Brownian force are the three dominant forces acting on the ions. Both the experimental and simulation results indicate that cone gas flow rates of ≤250 slph (standard liter per hour) are important for high ion transmission efficiency, as higher cone gas flow rates reduce the ion signal significantly. The simulation results also show that the ion transmission efficiency reduces exponentially with an increased ion source current. Additionally, the ion loss due to space-charge effects has been found to be predominant at a higher ion source current, a lower capillary voltage, and a stronger cone gas counterflow. The interaction of the ion driving force, ion opposing force, and ion dispersion is discussed to illustrate ion transport mechanism in the ion source at atmospheric pressure. [Figure not available: see fulltext.

Study of axial injection of polarized protons into the grenoble cyclotron; Contribution a l'etude de l'injection axiale pour protons polarises sur le cyclotron de Grenoble

Energy Technology Data Exchange (ETDEWEB)

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

1969-07-01

By injecting ions axially into a cyclotron, it is possible to accelerate particles (polarized particles, heavy ions, etc...) obtainable only with difficulty when an internal ion source is used. In this work, after justifying the choice of an axial injection device equipped with a 'pseudo-cylindrical' deflector for the Grenoble cyclotron, we study theoretically the principle of such a detector, the choice of its parameters, and the effect of this choice on the conditions of acceleration of the beam by the cyclotron. From the experimental point of view, this report describes two operations which made it possible to check that the chosen injection device operated satisfactorily, qualitatively initially (electron model), then quantitatively (proton model). In conclusion, we believe that the Grenoble cyclotron thus equipped will be able to provide a relatively dense beam of polarized protons. (author) [French] L'injection axiale d'ions dans un cyclotron permet d'accelerer des particules (particules polarisees, ions lourds... ) difficiles a obtenir avec une source interne d'ions. Dans ce travail, apres avoir justifie le choix d'un dispositif d'injection axiale equipe d'un deflecteur 'pseudo-cylindrique' pour le cyclotron de Grenoble, nous avons etudie, du point de vue theorique, le principe d'un tel deflecteur, le choix de ses parametres, et l'incidence de ce choix sur les conditions d'acceleration du faisceau par le cyclotron. Du point de vue experimental, ce rapport decrit deux manipulations qui ont permis de verifier le bon fonctionnement du dispositif d'injection retenu, qualitativement d'abord (modele a electrons), quantitativement ensuite (maquette a protons). En conclusion, nous estimons que le cyclotron de Grenoble ainsi equipe, peut fournir un faisceau relativement intense de protons polarises. (auteur)

Development of industrial ion implantation and ion assisted coating processes: A perspective

International Nuclear Information System (INIS)

Legg, K.O.; Solnick-Legg, H.

1989-01-01

Ion beam processes have gone through a series of developmental stages, from being the mainstay of the semiconductor industry for production of integrated circuits, to new commercial processes for biomedical, aerospace and other industries. Although research is still continuing on surface modification using ion beam methods, ion implantation and ion assisted coatings for treatment of metals, ceramics, polymers and composites must now be considered viable industrial processes of benefit in a wide variety of applications. However, ion implantation methods face various barriers to acceptability, in terms not only of other surface treatment processes, but for implantation itself. This paper will discuss some of the challenges faced by a small company whose primary business is development and marketing of ion implantation and ion-assisted coating processes. (orig.)

Fully kinetic simulation of ion acoustic and dust-ion acoustic waves

International Nuclear Information System (INIS)

Hosseini Jenab, S. M.; Kourakis, I.; Abbasi, H.

2011-01-01

A series of numerical simulations is presented, based on a recurrence-free Vlasov kinetic model using kinetic phase point trajectories. All plasma components are modeled kinetically via a Vlasov evolution equation, then coupled through Poisson's equation. The dynamics of ion acoustic waves in an electron-ion and in a dusty (electron-ion-dust) plasma configuration are investigated, focusing on wave decay due to Landau damping and, in particular, on the parametric dependence of the damping rate on the dust concentration and on the electron-to-ion temperature ratio. In the absence of dust, the occurrence of damping was observed, as expected, and its dependence to the relative magnitude of the electron vs ion temperature(s) was investigated. When present, the dust component influences the charge balance, enabling dust-ion acoustic waves to survive Landau damping even in the extreme regime where T e ≅ T i . The Landau damping rate is shown to be minimized for a strong dust concentration or/and for a high value of the electron-to-ion temperature ratio. Our results confirm earlier theoretical considerations and contribute to the interpretation of experimental observations of dust-ion acoustic wave characteristics.

Caracterisation de la qualite des eaux de I' oued Kebir Quest (Nord ...

African Journals Online (AJOL)

Mots cles : Kebir Ouest - Skikda - Bassin versant - Qualite - Pollution - Metaux lourds. Abstract .... approche servira au suivi de l 'evolution annuelle des concentrations des ..... Watershed Management: principles and practice. New York, Wiley ...

Fatores associados ao consumo de álcool e drogas entre estudantes universitários

Directory of Open Access Journals (Sweden)

Leonardo V E Rueda Silva

2006-04-01

Full Text Available OBJETIVO: Estudos recentes mostram o uso preocupante de álcool e drogas entre universitários. O objetivo do trabalho foi verificar o grau de associação entre o estilo de vida e situação socioeconômica e o uso de álcool, tabaco, medicamentos e "drogas ilícitas" nos últimos 12 meses entre universitários. MÉTODOS: A amostra compreendeu 926 alunos da área de Ciências Biológicas de uma universidade do Município de São Paulo, os quais responderam a questionário anônimo e de auto-preenchimento em 2000 e 2001. Foram utilizados os testes de análise de variância e qui-quadrado para verificar a correlação entre o uso de substâncias e as variáveis estudadas. RESULTADOS: Entre os alunos com alguma religião, o consumo de álcool foi de 83,1%, o de tabaco, 20,7% e o de "drogas ilícitas", 24,6%, nesse período. Entre os alunos que não possuíam religião, o consumo nas três categorias foi superior nos últimos 12 meses: álcool (89,3%, tabaco (27,7% e "drogas ilícitas" (37,7%. A renda familiar mensal mostrou-se relacionada ao uso de álcool e "drogas ilícitas" (p<0,001 para ambos. Os alunos que utilizaram tabaco e "drogas ilícitas" apresentavam mais horas livres nos dias úteis do que os alunos que não fumavam no período analisado (p=0,033 e p=0,008, respectivamente. CONCLUSÕES: O consumo de substâncias psicoativas entre os alunos estudados foi comum, indicando a necessidade de implementação de medidas para reduzir tal consumo. Alunos com renda familiar alta e sem religião podem ser considerados com maior risco de consumo de drogas nessa população.

Neutralized ion beam modification of cellulose membranes for study of ion charge effect on ion-beam-induced DNA transfer

Science.gov (United States)

Prakrajang, K.; Sangwijit, K.; Anuntalabhochai, S.; Wanichapichart, P.; Yu, L. D.

2012-02-01

Low-energy ion beam biotechnology (IBBT) has recently been rapidly developed worldwide. Ion-beam-induced DNA transfer is one of the important applications of IBBT. However, mechanisms involved in this application are not yet well understood. In this study plasma-neutralized ion beam was applied to investigate ion charge effect on induction of DNA transfer. Argon ion beam at 7.5 keV was neutralized by RF-driven plasma in the beam path and then bombarded cellulose membranes which were used as the mimetic plant cell envelope. Electrical properties such as impedance and capacitance of the membranes were measured after the bombardment. An in vitro experiment on plasmid DNA transfer through the cellulose membrane was followed up. The results showed that the ion charge input played an important role in the impedance and capacitance changes which would affect DNA transfer. Generally speaking, neutral particle beam bombardment of biologic cells was more effective in inducing DNA transfer than charged ion beam bombardment.

Response of thermal ions to electromagnetic ion cyclotron waves

Science.gov (United States)

Anderson, B. J.; Fuselier, S. A.

1994-01-01

Electromagnetic ion cyclotron waves generated by 10 - 50 keV protons in the Earth's equatorial magnetosphere will interact with the ambient low-energy ions also found in this region. We examine H(+) and He(+) distribution functions from approx. equals 1 to 160 eV using the Hot Plasma Composition Experiment instrument on AMPTE/CCE to investigate the thermal ion response to the waves. A total of 48 intervals were chosen on the basis of electromagnetic ion cyclotron (EMIC) wave activity: 24 with prevalent EMIC waves and 24 with no EMIC waves observed on the orbit. There is a close correlation between EMIC waves and perpendicular heated ion distributions. For protons the perpendicular temperature increase is modest, about 5 eV, and is always observed at 90 deg pitch angles. This is consistent with a nonresonant interaction near the equator. By contrast, He(+) temperatures during EMIC wave events averaged 35 eV and sometimes exceeded 100 eV, indicating stronger interaction with the waves. Furthermore, heated He(+) ions have X-type distributions with maximum fluxes occurring at pitch angles intermediate between field-aligned and perpendicular directions. The X-type He(+) distributions are consistent with a gyroresonant interaction off the equator. The concentration of He(+) relative to H(+) is found to correlate with EMIC wave activity, but it is suggested that the preferential heating of He(+) accounts for the apparent increase in relative He(+) concentration by increasing the proportion of He(+) detected by the ion instrument.

Production of C, N, O, and Ne ions by pulsed ion source and acceleration of these ions in the cyclotron

International Nuclear Information System (INIS)

Nakajima, Hisao; Kohara, Shigeo; Kageyama, Tadashi; Kohno, Isao

1977-01-01

The heavy ion source, of electron bombarded hot cathode type, is usually operated by applying direct current for arc discharge. In order to accelerate Ne 6+ ion in the cyclotron, a pulsed operation of this source was attempted. Ne 6+ and O 6+ ions were accelerated successfully up to 160 MeV and more than 0.1 μA of these ion were extracted from the cyclotron. C 5+ , Ne 7+ and 22 Ne 6+ ions were also extracted with a modest intensity of beam. The intensity of C 4+ , N 4+ , N 5+ , and O 5+ ions was increased about ten times. (auth.)

Purification by molecular sieve of helium used as inert cover gas in nuclear reactors; Epuration de l'helium de couverture des reacteurs nucleaires par adsorption sur tamis moleculaire

Energy Technology Data Exchange (ETDEWEB)

Rozenberg, J; Kahan, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

A method carried out at fairly low temperatures (between -50 and -80 deg. C) has been studied for the purification of the helium used as cover gas for heavy water in reactors. The use of the 5A molecular sieve has been adopted because of its superiority over other adsorbents in this temperature range. The particular problems connected with adsorption under dynamic conditions have been dealt with separately. The nitrogen adsorption isotherms have been plotted and the heat of adsorption calculated. (authors) [French] Une methode d'epuration, a temperature moderement basse (comprise entre -50 et -80 deg. C) de l'helium servant de couverture inerte a l'eau lourde des reacteurs a ete etudiee. L'emploi au tamis moleculaire 5A a ete retenu pour la superiorite de celui-ci sur d'autres adsorbants dans ce domaine de temperatures. Les problemes particuliers a l'adsorption en regime dynamique ont ete separement traites. Les isothermes d'adsorption d'azote ont ete tracees et la chaleur d'adsorp. tion calculee. (auteurs)

Vacinação contra a hepatite B entre cirurgiões dentistas

Directory of Open Access Journals (Sweden)

Martins Andréa Maria Eleutério de Barros Lima

2003-01-01

Full Text Available OBJETIVO: Inquéritos sorológicos realizados em diversos países mostraram uma maior prevalência da infecção pelo vírus da hepatite B (VHB em dentistas, especialmente entre os cirurgiões, do que na população geral. O estudo realizado objetivou determinar a prevalência e os fatores associados à vacinação contra hepatite B (HB entre os dentistas e investigar as principais razões alegadas para a não vacinação e vacinação incompleta. MÉTODOS: Foi conduzido um inquérito entre 299 cirurgiões dentistas residentes em Montes Claros, MG, por meio de questionário auto-aplicável. Foi determinada a prevalência de vacinação segundo o número de doses e os fatores associados à não vacinação e à vacinação incompleta através de regressão logística multinomial. RESULTADOS: Dos 299 questionários distribuídos, 296 (99% foram respondidos. Destes, 74,9% tomaram três doses; 14%, duas doses; 2%, uma dose e 10% não foram vacinados. A vacinação completa foi maior entre os que relataram fazer exclusivamente cirurgia e/ou periodontia (89%. A principal razão alegada para a não vacinação ou vacinação incompleta foi a necessitade de maiores informações. A não vacinação foi mais freqüente entre aqueles com mais de 40 anos (OR=8,62; IC 95%: 1,88-39,41 e os que não se reciclaram nos dois anos prévios ao inquérito (OR=2,72; IC 95%: 1,02-7,22. A vacinação incompleta foi maior entre os que não usam luva no trabalho (OR=2,32; IC 95%: 1,08-4,97. CONCLUSÃO: A falta de informação, possivelmente relacionada a menor reciclagem profissional, parece ser um dos principais fatores limitantes da vacinação.

Hybrid Lithium-ion Capacitor / Lithium-ion Battery System for Extended Performance

Data.gov (United States)

National Aeronautics and Space Administration — The proposed task will involve the design of a hybrid power system with lithium-ion (li-ion) capacitors (LICs), li-ion batteries and solar cells. The challenge in...

Metal negative ion beam extraction from a radio frequency ion source

Energy Technology Data Exchange (ETDEWEB)

Kanda, S.; Yamada, N.; Kasuya, T.; Romero, C. F. P.; Wada, M.

2015-04-08

A metal ion source of magnetron magnetic field geometry has been designed and operated with a Cu hollow target. Radio frequency power at 13.56 MHz is directly supplied to the hollow target to maintain plasma discharge and induce self-bias to the target for sputtering. The extraction of positive and negative Cu ion beams have been tested. The ion beam current ratio of Cu{sup +} to Ar{sup +} has reached up to 140% when Ar was used as the discharge support gas. Cu{sup −} ion beam was observed at 50 W RF discharge power and at a higher Ar gas pressure in the ion source. Improvement of poor RF power matching and suppression of electron current is indispensable for a stable Cu{sup −} ion beam production from the source.

Corposições entre o ver, o dizer e o agir

Directory of Open Access Journals (Sweden)

Catarina Mendes Resende

Full Text Available Resumo Este artigo enuncia as questões que mobilizam o coletivo de investigação “Corposições: Profanações entre afeto, performatividade e território”, explicitando o “como”, “onde” e “quando” os campos de atuação de seus integrantes se imbricam para construir um corpo comum. A partir de suas principais ferramentas de trabalho - a Composição em Tempo Real de João Fiadeiro e o Modo Operativo AND de Fernanda Eugenio - o jogo proposto pelo grupo é o de partilhar suas experiências, dando visibilidade ao que desestabiliza, ventila e amplia suas práticas e discursos. Tal proposição implica modos de ver específicos - a articulação entre corporeidade, afeto, território e performatividade - e modos de agir - uma investigação que é experimentação e laboratório, na qual são performadas intervenções entre dança e clínica.

Ion-temperature-gradient-driven modes in bi-ion magnetoplasma

Energy Technology Data Exchange (ETDEWEB)

Batool, Nazia; Mirza, Arshad M [Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Qamar, Anisa [Department of Physics, Peshawar University, NWFP 25120 (Pakistan)], E-mail: nazia.batool@ncp.edu.pk

2008-12-15

The toroidal ion-temperature-gradient (ITG)-driven electrostatic drift waves are investigated for bi-ion plasmas with equilibrium density, temperature and magnetic field gradients. Using Braginskii's transport equations for the ions and Boltzmann distributed electrons, the mode coupling equations are derived. New ITG-driven modes are shown to exist. The results of the present study should be helpful to understand several wave phenomena in space and tokamak plasmas.

Relaciones entre organizaciones y stakeholders: necesidad de una interacción mutua entre los diversos grupos de interés

Directory of Open Access Journals (Sweden)

Jorge Suárez Tirado

2007-12-01

Full Text Available En este ensayo intentaré explicar las relaciones y los riesgos existentes entre organizaciones y stakeholders (grupos de interés; adicionalmente, realizaré algunas observaciones al enfoque clásico planteado por Milton Friedman, sin el ánimo de entrar a explicar las características del entorno económico, político y social de la época (1970, e intentaré argumentar que en las circunstancias actuales (niveles de pobreza, aumento en la brecha social, problemas medioambientales, etc., las empresas tienen compromisos con los stakeholders y con la comunidad en general, que van más allá de la generación de utilidades para los propietarios. Posteriormente presentaré de una forma muy breve algunas herramientas que permiten comunicar el impacto de la empresa sobre la sociedad y en particular sobre los diversos stakeholders, como lo son las cuentas de excedente y el balance social que se constituyen en la principal herramienta de comunicación entre la empresa y los diversos grupos de interés o stakeholders

El Ciberacoso entre los estudiantes de Colombia: una investigación exploratoria

Directory of Open Access Journals (Sweden)

Giulia Mura

2013-12-01

Full Text Available El ciberacoso es un fenómeno relacionado con internet, reconocido y en crecimiento. Aunque el enfoque de la investigación en este campo está expandiéndose rápidamente, la mayoría de las investigaciones se centraron en las experiencias de adolescentes en países industrializados, como los de Europa occidental o países anglosajones. Pero, los jóvenes de los países en desarrollo ¿están expuestos a los mismos riesgos? Para responder a esta pregunta, este trabajo presenta una parte de los resultados de un proyecto más amplio, y centra su atención en la incidencia de episodios de ciberacoso entre los estudiantes de secundaria en Colombia. Los datos se recogieron sobre una muestra de 359 estudiantes, 64.1% varones y 35.9% mujeres, entre los 13 y los 19 años de edad, utilizando un cuestionario entregado en horario escolar. El análisis demuestra que los episodios de ciberacoso están bastante extendidos en el grupo de la muestra; teniendo en cuenta que más del 60% de los jóvenes entrevistados estuvo involucrado (ya sea como víctima o como acosador en al menos 2 episodios en los 6 meses anteriores a la investigación. Las diferencias entre los sexos han sido analizadas, pero no han dado resultados significativos. En conclusión este estudio pone en evidencia la necesidad de una investigación más profunda y amplia del ciberacoso, tanto entre la población masculina como entre la femenina, de los así llamados "países en desarrollo", porque parece que la difusión de éste fenómeno está afectando también a la juventud de éstos países.

Creencias sobre la insuficiencia renal crónica entre expertos y profanos

Directory of Open Access Journals (Sweden)

Esperanza Vélez Vélez

2013-09-01

Full Text Available Objetivo: Identificar las creencias y representaciones sobre la insuficiencia renal crónica (IRC en pacientes, población general y expertos. Metodología: Estudio descriptivo transversal que analiza una muestra de 120 participantes seleccionados por muestreo no probabilístico por cuotas. Se crearon cinco grupos de estudio en función de su nivel de interacción con la enfermedad. La herramienta utilizada fue el Cuestionario de Creencias Sobre la Enfermedad. Resultados: Identidad, Controlabilidad, Mutabilidad, Responsabilidad Personal y Azar no presentan diferencias significativas entre los grupos estudiados. El factor Causas muestra diferencias estadísticamente significativas entre el grupo de pacientes con universitarios de ciencias de la salud y expertos (p<0,001 y entre otros universitarios con universitarios ciencias de la salud y expertos (p<0.001. El factor Incapacidad muestra diferencias significativas entre pacientes, universitarios y población general (p<0,001 y entre expertos con otros universitarios y población general (p<0,001. Los pacientes ofrecen un menor número de síntomas asociados tanto a la IRC como a la hemodiálisis (HD. Y en cuanto a las causas, las de origen biológico y conductuales son las más consideradas por todos los grupos. Solo el grupo de pacientes en HD considera el azar factor causal de la enfermedad. Conclusiones: En oposición al modelo científico, pacientes y población general comparten la idea de que la IRC es curable, depende en gran medida del azar y de hábitos de conducta y es menos grave de lo que opinan expertos. La experiencia con la enfermedad aporta más información (no necesariamente conocimiento que es recordada en función de la utilidad para lograr un mayor bienestar o una mejora de los cuidados.

Proceedings of the 'INS workshop on ECR ion sources for multiply-charged heavy ions'

International Nuclear Information System (INIS)

1995-02-01

This workshop was held on December 1 and 2, 1994 at the Institute for Nuclear Study, University of Tokyo. The performance of ion sources is crucial for all researches and applications that use ion beam. The performance of ECR ion sources is strongly dependent on heuristic knowledge and innovation. From these viewpoints, it is useful to exchange information on the status of the existing sources, the performance of the new sources, and the design of the future sources between the source builders and the users. There were unexpected more than 70 participants and 20 contributions. The lectures were given on the present status of NIRS-ECR, SF-ECR, INS ISOL-ECR, RCNP ECR and EBIS ion sources, the production of multiply charged metallic ions with Hyper ECR or by plasma cathode method, the processing of ceramic rods and the ion production with OCTOPUS, the modeling of multi-charged ion production, the design of an advanced minimum B for ECR multi-charged ion source, the design, construction and operation of 18 GHz HiECR ion source, the construction and test operation of JAERI 18 GHz ion source, the design of an ECR ion source for the HIMAC, a 14.5 GHz ECR ion source at RIKEN, TMU 14 GHz ECR ion source, ''NANOGAN'' ECR ion source and its irradiation system, the optimization of the ECR ion source for optically pumped polarized ion source and so on. (K.I.)

Proceedings of the `INS workshop on ECR ion sources for multiply-charged heavy ions`

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-01

This workshop was held on December 1 and 2, 1994 at the Institute for Nuclear Study, University of Tokyo. The performance of ion sources is crucial for all researches and applications that use ion beam. The performance of ECR ion sources is strongly dependent on heuristic knowledge and innovation. From these viewpoints, it is useful to exchange information on the status of the existing sources, the performance of the new sources, and the design of the future sources between the source builders and the users. There were unexpected more than 70 participants and 20 contributions. The lectures were given on the present status of NIRS-ECR, SF-ECR, INS ISOL-ECR, RCNP ECR and EBIS ion sources, the production of multiply charged metallic ions with Hyper ECR or by plasma cathode method, the processing of ceramic rods and the ion production with OCTOPUS, the modeling of multi-charged ion production, the design of an advanced minimum B for ECR multi-charged ion source, the design, construction and operation of 18 GHz HiECR ion source, the construction and test operation of JAERI 18 GHz ion source, the design of an ECR ion source for the HIMAC, a 14.5 GHz ECR ion source at RIKEN, TMU 14 GHz ECR ion source, ``NANOGAN`` ECR ion source and its irradiation system, the optimization of the ECR ion source for optically pumped polarized ion source and so on. (K.I.).

Relación entre conducta parental y adherencia al tratamiento en diabetes infantil

Directory of Open Access Journals (Sweden)

Mónica María Novoa Gómez

2008-01-01

Full Text Available En este artículo, enmarcado en la psicología de la salud, se pretende identificar la relación que existe entre la conducta parental y la adherencia al tratamiento a partir de un diseño no-experimental de tipo transversal descriptivo correlacional, en una muestra de niños con diabetes tipo I, entre 8 y 11 años de edad, con un tiempo desde el diagnóstico de entre uno y tres años. Los resultados analizados señalan la relación que existe entre los comportamientos que engloba la variable de conducta parental y adherencia al tratamiento, pudiendo incluso diferenciar aquellos comportamientos más representativos para cada categoría; así por ejemplo, se encontró que la comunicación afectiva es el comportamiento parental que más está correlacionado con las conductas de adhesión. Con respecto a las conductas de adhesión al tratamiento, la dieta fue la conducta de este tipo que más se correlacionó con comportamientos parentales.

ENTRE IDEOLOGIA E UTOPIA: A DIALÉTICA DA IMAGINAÇÃO EM MANNHEIM

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Mateus Augusto de Oliveira

2017-07-01

Full Text Available O objetivo deste trabalho é analisar o conceito de utopia elaborado pelo sociólogo húngaro Karl Mannheim. Para tanto, estudaremos o papel desempenhado pela obra Ideologia e utopia no pensamento de Mannheim. O livro é a carta de fundação da sociologia do conhecimento como disciplina autônoma. Mostraremos como Ideologia e utopia desenvolve uma aproximação entre imaginário e política. Mannheim argumenta que toda sociedade se alicerça em ficções, símbolos, mitos e ritos. O sociólogo distancia-se de Marx e Engels ao criticar a distinção entre consciência alienada e consciência esclarecida, ciência e ideologia. No cerne da sociologia do conhecimento desenvolvida por Mannheim está uma polarização entre ideologia e utopia, definida pelo filósofo Paul Ricoeur como “dialética da imaginação”. Para Mannheim, o conceito de ‘utopia’ se desenvolveria em contraposição à noção de ‘ideologia’: a tensão entre um e outro estaria na base de toda comunidade.

Asociación entre agenesia dental y maloclusión en pacientes pediátricos

Directory of Open Access Journals (Sweden)

A. Carolina Medina

2013-07-01

Full Text Available Introducción: La agenesia dental es la anomalía del desarrollo más frecuente en el ser humano, asociándose a maloclusiones y alteraciones funcionales. Objetivo: El objetivo de la presente investigación es determinar la asociación entre la agenesia de dientes permanentes y la presencia de maloclusiones en pacientes pediátricos en el área Metropolitana de Caracas, Venezuela. Material y métodos: Fueron evaluados 1.188 radiografías panorámicas y 648 registros ortodóncicos de pacientes sanos con edades entre 5 y 18 años, registrando agenesia de dientes permanentes, exceptuando terceros molares. La maloclusión se diagnosticó según Angle. Fueron calculados estadísticos descriptivos, diferencias entre promedios y correlaciones entre variables (t de Student, rho de Pearson, p=0,05, odds ratio. Resultados: La prevalencia de agenesia fue 5,6%, siendo la media 1,64 y afectando mayormente al sexo femenino (1,44:1. Los dientes más afectados fueron segundos premolares inferiores (35,19%, e incisivos laterales superiores (30,55%. La prevalencia de maloclusión fue mayor en el grupo con agenesia dental (Clase I 52%, Clase II 31%, Clase III 17% al comparar con el grupo control (Clase I 77%, Clase II 14%, Clase III 9%; habiendo correlación estadísticamente significativa entre el número de dientes ausentes y Clase III. Conclusión: La prevalencia y distribución de agenesia dental variaron entre géneros, siendo el femenino el más afectado. Hubo correlación positiva estadísticamente significativa entre el número de dientes afectados y la maloclusión Clase III.

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes.

Science.gov (United States)

Geise, Geoffrey M; Cassady, Harrison J; Paul, Donald R; Logan, Bruce E; Hickner, Michael A

2014-10-21

Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The charge density and polarizability

Effects of energy content and energy density of pre-portioned entrées on energy intake.

Science.gov (United States)

Blatt, Alexandria D; Williams, Rachel A; Roe, Liane S; Rolls, Barbara J

2012-10-01

Pre-portioned entrées are commonly consumed to help control portion size and limit energy intake. The influence of entrée characteristics on energy intake, however, has not been well studied. We determined how the effects of energy content and energy density (ED, kcal/g) of pre-portioned entrées combine to influence daily energy intake. In a crossover design, 68 non-dieting adults (28 men and 40 women) were provided with breakfast, lunch, and dinner on 1 day a week for 4 weeks. Each meal included a compulsory, manipulated pre-portioned entrée followed by a variety of unmanipulated discretionary foods that were consumed ad libitum. Across conditions, the entrées were varied in both energy content and ED between a standard level (100%) and a reduced level (64%). Results showed that in men, decreases in the energy content and ED of pre-portioned entrées acted independently and added together to reduce daily energy intake (both P kcal/day; P lunch, but at dinner and for the entire day the effects depended on the interaction of the two factors (P daily energy intake in women by 14% (289 ± 35 kcal/day; P daily energy intake and could influence the effectiveness of such foods for weight management.

Space-charge compensation of highly charged ion beam from laser ion source

International Nuclear Information System (INIS)

Kondrashev, S.A.; Collier, J.; Sherwood, T.R.

1996-01-01

The problem of matching an ion beam delivered by a high-intensity ion source with an accelerator is considered. The experimental results of highly charged ion beam transport with space-charge compensation by electrons are presented. A tungsten thermionic cathode is used as a source of electrons for beam compensation. An increase of ion beam current density by a factor of 25 is obtained as a result of space-charge compensation at a distance of 3 m from the extraction system. The process of ion beam space-charge compensation, requirements for a source of electrons, and the influence of recombination losses in a space-charge-compensated ion beam are discussed. (author)

Mõned vaated tänavusele PÖFFile / Donald Tomberg

Index Scriptorium Estoniae

Tomberg, Donald, 1972-

2009-01-01

"EurAsia" võistlusprogrammi filmidest "Leierkastiviis" ("Meloodia väntorelile", rež. Kira Muratova, Ukraina), "Lourdes" (rež. Jessica Hausner, Austria - Prantsusmaa - Saksamaa) ja "Kahe maailma vahel" (rež. Vimukthi Jayasundra, Sri Lanka)

L’approche sociopsychologique de Horkheimer, entre Fromm et Adorno

Directory of Open Access Journals (Sweden)

Katia Genel

2010-08-01

Full Text Available Le cadre du programme interdisciplinaire de recherche défini par Max Horkheimer dans les années 1930 doit beaucoup à Erich Fromm, qui a introduit la psychologie sociale dans la Théorie critique de la société. Or, une décennie plus tard, Fromm est la cible privilégiée des attaques et sa théorie apparaît désormais comme incompatible avec les positions défendues par Horkheimer et Adorno. Partant de ces tensions qui ont marqué l’histoire de l’École de Francfort, le présent article vise à éclaircir le déplacement qu’elles traduisent sur le plan épistémologique. Si Horkheimer et Fromm partagent des prémisses communes, le premier, dans son travail avec Adorno, se rapproche de manière croissante de la doctrine freudienne alors que le second s’en éloigne. Nous voudrions montrer que l’accord entre Fromm et Horkheimer fut surtout négatif puisqu’il portait sur la critique de Freud : les divergences entre les deux penseurs apparaissent clairement, dès lors qu’on pose en profondeur la question de l’usage de la psychanalyse pour analyser l’un des problèmes centraux de la théorie de la société, l’antagonisme entre individu et société.

Relación entre variables neurocognitivas y personalidad en delincuentes

Directory of Open Access Journals (Sweden)

Juan Antonio Becerra García

2014-12-01

Full Text Available Recientes estudios muestran que rasgos de personalidad del Modelo de los Cinco Factores y funciones neurocognitivas frontales comparten una misma base neurobiológica. En población penitenciaria las relaciones entre estas funciones y rasgos ha sido poco explorada. Este estudio pretende examinar la relación entre personalidad y funciones neurocognitivas en delincuentes y determinar si las medidas de funcionamiento neurocognitivo frontal contribuyen a predecir algún porcentaje de varianza en rasgos de personalidad de muestras penitenciarias. Noventa y nueve hombres (distribuidos en grupos: agresores sexuales de adultos, delincuentes no sexuales y grupo control realizaron el Inventario de Personalidad NEO de Cinco Factores (NEO-FFI y el Trail Making Test (TMT, partes A y B. La ejecución en la parte A del TMT se relaciono con el nivel de Extraversión de los delincuentes sexuales y con el nivel de Neuroticismo de delincuentes no sexuales y explica un porcentaje significativo de la varianza de estos dominios de personalidad en ambos grupos. En conclusión, la relación entre el funcionamiento neurocognitivo y la personalidad parece ser diferente en función del tipo de delito cometido, aunque los resultados deben ser interpretados de forma preliminar.

Ion sources for initial use at the Holifield radioactive ion beam facility

International Nuclear Information System (INIS)

Alton, G.D.

1994-01-01

The Holifield Radioactive Ion Beam Facility (HRIBF) now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility; the choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. A high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the HRIBF because of its low emittance, relatively high ionization efficiencies and species versatility, and because it has been engineered for remote installation, removal and servicing as required for safe handling in a high-radiation-level ISOL facility. Prototype plasma-sputter negative ion sources and negative surfaceionization sources are also under design consideration for generating negative radioactive ion beams from high electron-affinity elements. A brief review of the HRIBF will be presented, followed by a detailed description of the design features, operational characteristics, ionization efficiencies, and beam qualities (emittances) of these sources

Evaluation of Negative-Ion-Beam Driver Concepts for Heavy Ion Fusion

International Nuclear Information System (INIS)

Grisham, Larry R.

2002-01-01

We evaluate the feasibility of producing and using atomically neutral heavy ion beams produced from negative ions as drivers for an inertial confinement fusion reactor. Bromine and iodine appear to be the most attractive elements for the driver beams. Fluorine and chlorine appear to be the most appropriate feedstocks for initial tests of extractable negative ion current densities. With regards to ion sources, photodetachment neutralizers, and vacuum requirements for accelerators and beam transport, this approach appears feasible within existing technology, and the vacuum requirements are essentially identical to those for positive ion drivers except in the target chamber. The principal constraint is that this approach requires harder vacuums in the target chamber than do space-charge-neutralized positive ion drivers. With realistic (but perhaps pessimistic) estimates of the total ionization cross section, limiting the ionization of a neutral beam to less than 5% while traversing a four -meter path would require a chamber pressure of no more than 5 x 10 -5 torr. Alternatively, even at chamber pressures that are too high to allow propagation of atomically neutral beams, the negative ion approach may still have appeal, since it precludes the possibly serious problem of electron contamination of a positive ion beam during acceleration, drift compression, and focusing

The ion polytropic coefficient in a collisionless sheath containing hot ions

Energy Technology Data Exchange (ETDEWEB)

Lin, Binbin; Xiang, Nong, E-mail: xiangn@ipp.ac.cn; Ou, Jing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

2016-08-15

The fluid approach has been widely used to study plasma sheath dynamics. For a sheath containing hot ions whose temperature is greater than the electron's, how to truncate the fluid hierarchy chain equations while retaining to the fullest extent of the kinetic effects is always a difficult problem. In this paper, a one-dimensional, collisionless sheath containing hot ions is studied via particle-in-cell simulations. By analyzing the ion energy equation and taking the kinetic effects into account, we have shown that the ion polytropic coefficient in the vicinity of the sheath edge is approximately constant so that the state equation with the modified polytropic coefficient can be used to close the hierarchy chain of the ion fluid equations. The value of the polytropic coefficient strongly depends on the hot ion temperature and its concentration in the plasma. The semi-analytical model is given to interpret the simulation results. As an application, the kinetic effects on the ion saturation current density in the probe theory are discussed.

Ion mobility spectrometry

CERN Document Server

Eiceman, GA

2005-01-01

Key Developments for Faster, More Precise Detection Capabilities Driven by the demand for the rapid and advanced detection of explosives, chemical and biological warfare agents, and narcotics, ion mobility spectrometry (IMS) undergone significant refinements in technology, computational capabilities, and understanding of the principles of gas phase ion chemistry and mobility. Beginning with a thorough discussion of the fundamental theories and physics of ion mobility, Ion Mobility Spectrometry, Second Edition describes the recent advances in instrumentation and newly

Duopigatron ion source studies

International Nuclear Information System (INIS)

Bacon, F.M.; Bickes, R.W. Jr.; O'Hagan, J.B.

1978-07-01

Ion source performance characteristics consisting of total ion current, ion energy distribution, mass distribution, and ion current density distribution were measured for several models of a duopigatron. Variations on the duopigatron design involved plasma expansion cup material and dimensions, secondary cathode material, and interelectrode spacings. Of the designs tested, the one with a copper and molybdenum secondary cathode and a mild steel plasma expansion cup proved to give the best results. The ion current density distribution was peaked at the center of the plasma expansion cup and fell off to 80 percent of the peak value at the cup wall for a cup 15.2 mm deep. A total ion current of 180 mA consisting of 60 to 70 percent atomic ions was produced with an arc current of 20 A and source pressure of 9.3 Pa. More shallow cups produced a larger beam current and a more sharply peaked ion current density distribution. Typical ion energy distributions were bell-shaped curves with a peak 10 to 20 V below anode potential and with ion energies extending 30 to 40 V on either side of the peak

C-terminal peptide extension via gas-phase ion/ion reactions

Science.gov (United States)

Peng, Zhou; McLuckey, Scott A.

2015-01-01

The formation of peptide bonds is of great importance from both a biological standpoint and in routine organic synthesis. Recent work from our group demonstrated the synthesis of peptides in the gas-phase via ion/ion reactions with sulfo-NHS reagents, which resulted in conjugation of individual amino acids or small peptides to the N-terminus of an existing ‘anchor’ peptide. Here, we demonstrate a complementary approach resulting in the C-terminal extension of peptides. Individual amino acids or short peptides can be prepared as reagents by incorporating gas phase-labile protecting groups to the reactive C-terminus and then converting the N-terminal amino groups to the active ketenimine reagent. Gas-phase ion/ion reactions between the anionic reagents and doubly protonated “anchor” peptide cations results in extension of the “anchor” peptide with new amide bond formation at the C-terminus. We have demonstrated that ion/ion reactions can be used as a fast, controlled, and efficient means for C-terminal peptide extension in the gas phase. PMID:26640400

Cobalt alloy ion sources for focused ion beam implantation

Energy Technology Data Exchange (ETDEWEB)

Muehle, R.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Zimmermann, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1997-09-01

Cobalt alloy ion sources have been developed for silicide formation by focused ion beam implantation. Four eutectic alloys AuCo, CoGe, CoY and AuCoGe were produced by electron beam welding. The AuCo liquid alloy ion source was investigated in detail. We have measured the emission current stability, the current-voltage characteristics, and the mass spectrum as a function of the mission current. (author) 1 fig., 2 refs.

Studies on indigenous ion exchange resins: alkali metal ions-hydrogen ion exchange equilibria

International Nuclear Information System (INIS)

Shankar, S.; Kumar, Surender; Venkataramani, B.

2001-01-01

With a view to select a suitable ion exchange resin for the removal of radionuclides (such as cesium, strontium etc.) from low level radioactive effluents, alkali metal ion -H' exchanges on nine indigenous gel- and macroporous-type and nuclear grade resins have been studied at a total ionic strength of 0.1 mol dm .3 (in the case ofCs' -H' exchange it was 0.05 mol dm .3 ). The expected theoretical capacities were not attained by all the resins for the alkali metal ions. The water content (moles/equiv.) of the fully swollen resins for different alkali metal ionic forms do not follow the usual sequence of greater the tendency of the cation to hydrate the higher the water uptake, but a reverse trend. The ion exchange isotherms (plots of equivalent fractions of the ion in resin phase, N M1 to that in solution, N M ) were not satisfactory and sorption of cations, for most of the resins, was possible only when the acidity of the solution was lowered. The variations of the selectivity coefficient, K, with N M show that the resins are highly cross linked and the selectivity sequence: Cs + >K + >Na + >Li + , obtained for all the resins indicate that hydrated ions were involved in the exchange process. However, the increase in the selectivity was not accompanied by the release of water, but unusual uptake of water, during the exchange process. The characteristics of macroporous resins were not significantly different from those of the gel-type resins. The results are discussed in terms of heterogeneity in the polymer net work, improper sulphonation process resulting in the formation of functional groups at inaccessible sites with weak acidic character and the overall lack of control in the preparation of different resins. (author)

Maximizing Ion Current by Space Charge Neutralization using Negative Ions and Dust Particles

International Nuclear Information System (INIS)

Smirnov, A.; Raitses, Y.; Fisch, N.J.

2005-01-01

Ion current extracted from an ion source (ion thruster) can be increased above the Child-Langmuir limit if the ion space charge is neutralized. Similarly, the limiting kinetic energy density of the plasma flow in a Hall thruster might be exceeded if additional mechanisms of space charge neutralization are introduced. Space charge neutralization with high-mass negative ions or negatively charged dust particles seems, in principle, promising for the development of a high current or high energy density source of positive light ions. Several space charge neutralization schemes that employ heavy negatively charged particles are considered. It is shown that the proposed neutralization schemes can lead, at best, only to a moderate but nonetheless possibly important increase of the ion current in the ion thruster and the thrust density in the Hall thruster

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1982-01-01

Ion-Selective Electrode Reviews, Volume 3, provides a review of articles on ion-selective electrodes (ISEs). The volume begins with an article on methods based on titration procedures for surfactant analysis, which have been developed for discrete batch operation and for continuous AutoAnalyser use. Separate chapters deal with detection limits of ion-selective electrodes; the possibility of using inorganic ion-exchange materials as ion-sensors; and the effect of solvent on potentials of cells with ion-selective electrodes. Also included is a chapter on advances in calibration procedures, the d

An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy.

Science.gov (United States)

Cao, Yun; Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia

2014-02-01

A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C(5+) ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C(5+) ion beam was got when work gas was CH4 while about 262 eμA of C(5+) ion beam was obtained when work gas was C2H2 gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

Relaciones entre el sueño y la adicción

OpenAIRE

Cañellas, Francesca; de Lecea, Luis

2012-01-01

La interacción entre los trastornos del sueño y el abuso de sustancias es ya conocida, pero seguramente más compleja de lo que se pensaba. Existe tanto una relación positiva entre tener un trastorno por uso de substancias y sufrir un trastorno de sueño, como viceversa. Los efectos sobre el sueño dependen de la substancia utilizada, pero se ha demostrado que tanto durante su uso como en período de abstinencia los consumidores tienen diferentes problemas de sueño y fundamentalmente un sueño más...

Nonlinear dust-ion-acoustic waves in a multi-ion plasma with ...

Indian Academy of Sciences (India)

The basic features of such dust-ion-acoustic solitary and shock waves have been ... ion plasmas because of its vital role in understanding different types of ... cannot support the usual ion-acoustic waves, but can support the DIA waves of ...

Low energy ion beam dynamics of NANOGAN ECR ion source

Energy Technology Data Exchange (ETDEWEB)

Kumar, Sarvesh, E-mail: sarvesh@iuac.res.in; Mandal, A.

2016-04-01

A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

Radioactive ion beam production challenges at the Holifield Heavy Ion Research Facility

International Nuclear Information System (INIS)

Meigs, M.J.; Alton, G.D.; Dowling, D.T.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Mills, G.D.; Mosko, S.W.; Olsen, D.K.; Tatum, B.A.

1992-01-01

The radioactive ion beam (RIB) project at the Holifield Heavy Ion Research Facility (HHIRF) will provide for reconfiguration of the HHIRF accelerator system to enable provision of low-intensity RIBs for nuclear and astrophysics research. As we have progressed with the design of the reconfiguration, we have encountered several challenges that were not immediately obvious when first contemplating the project. The challenges do not seem insurmountable but should keep life interesting for those of us doing the work. A brief review of the project will allow a better understanding of the challenges in RIB production. Radioactive ion beams will be produced with the Isotope Separator On-Line (ISOL) postacceleration technique. In particular, radioactive atoms will be produced by reactions in the thick stopping target of an ISOL-type target-ion source assembly using intense beams from the Oak Ridge Isochronous Cyclotron equipped with a light-ion internal source. This ISOL target-ion source assembly will be mounted on a high-voltage platform with a mass separator. The target ion source will operate at potentials up to 50 kV with respect to the high voltage platform. The radioactive atoms produced by nuclear reactions in the target diffuse to the surface of the heated target material, desorb from this surface, and effuse through a heated transfer tube into an ion source where ionization and extraction take place. Two types of ion sources will be initially considered. A Forced Electron Beam Induced Arc Discharge source, similar to those used by the ISOLDE facility at CERN and by the UNISOR facility at ORNL, will be built to produce positive ions. These positive ions will be focused through an alkali vapor charge-exchange canal to produce negative ions for tandem injection. In addition, a direct negative surface ionization addition or modification to the above source will be built and investigated

Improvement of highly charged ion production in the ECR source of heavy ions

International Nuclear Information System (INIS)

Shirkov, G.D.

1996-01-01

Some physical limitations of the highly charged ion production in the ECR source are analyzed in this report. A few possible ways to improve the output of highly charged ions from the ECR source for heavy ions are proposed. A new library of computer codes for the numerical simulation of heavy ion production in the ECR ion source is used to examine these ways to improve the ECR source operation according to the CERN program of heavy ion acceleration. copyright 1996 American Institute of Physics

Co-variabilidad de la temperatura superficial del mar entre cuencas del Hemisferio Sur

Directory of Open Access Journals (Sweden)

Ana Laura Berman

2011-12-01

Full Text Available En este trabajo se estudian relaciones estadísticas entre diferentes regiones de los océanos del Hemisferio Sur en todo el espacio tiempo-frecuencia durante los últimos cincuenta años aplicando la metodología de transformada ondeletas de coherencia a promedios anuales de anomalías mensuales de temperatura superficial del mar. Entre los resultados más relevantes encontrados debe mencionarse que las regiones del oeste y centro del Pacífico tropical tienen una estrecha relación en oscilaciones menores a 8 años y en oscilaciones alrededor de 12 años pero notables desacoples son detectados en el resto del espacio de frecuencias. Por otra parte, la relación entre las regiones del oeste y del este del Pacífico tropical es significativa sólo en oscilaciones menores a 8 años con una clara interrupción durante la década de 1980. Importantes conexiones en oscilaciones interdecadales son detectadas entre las regiones del oeste y centro del Pacifico subtropical. En el Océano Atlántico se encuentran relaciones significativas en un amplio rango de frecuencias entre las regiones del oeste y, especialmente, entre las regiones tropicales mientras que en el Océano Indico solo se observan relaciones importantes entre áreas subtropicales en oscilaciones decadales e interdecadales. El análisis también revela fuertes conexiones entre las tres cuencas oceánicas en diferentes bandas de frecuencia.Relations among different regions of the Southern Hemisphere oceans in the whole time-frequency space during the last fifty years are studied applying the methodology of Wavelet Coherence Analysis to annual means of monthly anomalies of sea surface temperature. Among the most relevant results, it must be mentioned that the western and central regions of the tropical Pacific have a close relation in oscillations shorter than 8 years and in oscillations around 12 years but important disconnections are detected in the rest of the space of frequencies

Prevalencia de consumo de tabaco entre las medicas y enfermeras de la comunidad de Madrid

Directory of Open Access Journals (Sweden)

Fernández Ruiz Mª Luisa

1999-01-01

Full Text Available FUNDAMENTOS: El tabaquismo es responsable de una elevada mortalidad y morbilidad en nuestro pais. El tabaquismo de los profesionales de la salud tiene influencia sobre los hábitos de la población. En España, el tabaquismo esta incrementándose entre las mujeres. El objetivo de nuestro estudio es estudiar la prevalencia de consumo de tabaco entre las médicas y enfermeras de la Comunidad de Madrid, así como sus actitudes y conocimientos respecto al tabaquismo. MÉTODOS: Se ha realizado un estudio descriptivo transversal entre las mujeres profesionales de la salud (médicas y enfermeras de la Comunidad de Madrid, mediante una encuesta sobre hábito tabáquico, en un muestreo polietápico por conglomerados. RESULTADOS: Se han estudiado 1.235 profesionales ( 435 médicas y 800 enfermeras. El 43,07% del total son fumadoras, siendo el tabaquismo mayor en las enfermeras (47,62% que en las médicas (34,71%, y entre quienes trabajan en atención especializada (46,68% que entre las que lo hacen en atención primaria (35,29%. El tabaquismo fue diferente en ambas profesiones.según la edad En las médicas era menor tabaquismo en las edades entre 20 y 30 años (22,88%, y en las enfermeras este grupo de edad era el que tenia un mayor porcentaje de fumadoras (52,38%. Eran exfumadoras el 18,3% del total de las encuestadas, y el 64,65% de las que fumaban señalaron que habían intentado dejarlo. Un 2,93% fumaban delante de los/as pacientes, y un 14,94% pensaban que debía permitirse fumar en las salas de espera. El 27,46% creían que estaba permitido fumar en su area de trabajo, y el 90,64% señaló que se fumaba habitualmente en las salas de uso común del personal sanitario, y un 30,37% respondió que existía un lugar especifico para fumar en el centro de trabajo. CONCLUSIONES: La prevalencia de tabaquismo entre las profesionales de la salud, médicas y enfermeras, de la Comunidad de Madrid, es elevada, superior a la de la población general de igual edad

Plasma focus as an heavy ion source in the problem of heavy ion fusion

International Nuclear Information System (INIS)

Gribkov, V.A.; Dubrovskij, A.V.; Kalachev, N.V.; Krokhin, O.N.; Silin, P.V.; Nikulin, V.Ya.; Cheblukov, Yu.N.

1984-01-01

Results of experiments on the ion flux formation in a plasma focus (PF) to develop a multicharged ion source for thermonuclear facility driver are presented. In plasma focus accelerating section copper ions were injected. Advantages of the suggested method of ion beam formation are demonstrated. Beam emittance equalling < 0.1 cmxmrad is obtained. Plasma focus ion energy exceeds 1 MeV. Plasma focus in combination with a neodymium laser is thought to be a perspective ion source for heavy ion fusion

La discapacidad entre poblaciones refugiadas y afectadas por conflictos

OpenAIRE

Reilly, Rachael

2010-01-01

La Comisión de Mujeres Refugiadas lanzó en el año 2007 un importante proyecto de investigación para evaluar la situación de las personas con discapacidad entre las poblaciones desplazadas o afectadas por conflictos.

Ion-ion and ion-solvent interactions in lithium imidazolide electrolytes studied by Raman spectroscopy and DFT models.

Science.gov (United States)

Scheers, Johan; Niedzicki, Leszek; Zukowska, Grażyna Z; Johansson, Patrik; Wieczorek, Władysław; Jacobsson, Per

2011-06-21

Molecular level interactions are of crucial importance for the transport properties and overall performance of ion conducting electrolytes. In this work we explore ion-ion and ion-solvent interactions in liquid and solid polymer electrolytes of lithium 4,5-dicyano-(2-trifluoromethyl)imidazolide (LiTDI)-a promising salt for lithium battery applications-using Raman spectroscopy and density functional theory calculations. High concentrations of ion associates are found in LiTDI:acetonitrile electrolytes, the vibrational signatures of which are transferable to PEO-based LiTDI electrolytes. The origins of the spectroscopic changes are interpreted by comparing experimental spectra with simulated Raman spectra of model structures. Simple ion pair models in vacuum identify the imidazole nitrogen atom of the TDI anion to be the most important coordination site for Li(+), however, including implicit or explicit solvent effects lead to qualitative changes in the coordination geometry and improved correlation of experimental and simulated Raman spectra. To model larger aggregates, solvent effects are found to be crucial, and we finally suggest possible triplet and dimer ionic structures in the investigated electrolytes. In addition, the effects of introducing water into the electrolytes-via a hydrate form of LiTDI-are discussed.

Experiments on secondary ion emission with multicharged keV ion bombardement

International Nuclear Information System (INIS)

Della Negra, S.; Depauw, J.; Joret, H.; Le Beyec, Y.; Schweikert, E.A.

1987-01-01

An electron cyclotron resonance ion source was used to study the influence of the incident charge state of keV ions on secondary ion emission. The experiments were run with 18 keV Arn+ (1 < n < 11) beams produced by a minimafios source. Various types of targets were bombarded by the ion beam and the sputtered ionized species were identified by time of flight mass spectrometry. The experimental arrangement is detailed and preliminary results are indicated

A heating mechanism of ions due to large amplitude coherent ion acoustic wave

International Nuclear Information System (INIS)

Yajima, Nobuo; Kawai, Yoshinobu; Kogiso, Ken.

1978-05-01

Ion heating mechanism in a plasma with a coherent ion acoustic wave is studied experimentally and numerically. Ions are accelerated periodically in the electrostatic potential of the coherent wave and their oscillation energy is converted into the thermal energy of ions through the collision with the neutral atoms in plasma. The Monte Carlo calculation is applied to obtain the ion temperature. The amplitude of the electrostatic potential, the mean number of collisions and the mean life time of ions are treated as parameters in the calculation. The numerical results are compared with the experiments and both of them agree well. It is found that the ion temperature increases as the amplitude of the coherent wave increases and the high energy tail in the distribution function of ions are observed for the case of large wave-amplitude. (author)

Molecular and negative ion production by a standard electron cyclotron resonance ion source

Energy Technology Data Exchange (ETDEWEB)

Racz, R. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, H-4026 Debrecen (Hungary); University of Debrecen, Egyetem ter 1, H-4010 Debrecen (Hungary); Biri, S.; Juhasz, Z.; Sulik, B. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, H-4026 Debrecen (Hungary); Palinkas, J. [University of Debrecen, Egyetem ter 1, H-4010 Debrecen (Hungary)

2012-02-15

Molecular and negative ion beams, usually produced in special ion sources, play an increasingly important role in fundamental and applied atomic physics. The ATOMKI-ECRIS is a standard ECR ion source, designed to provide highly charged ion (HCI) plasmas and beams. In the present work, H{sup -}, O{sup -}, OH{sup -}, O{sub 2}{sup -}, C{sup -}, C{sub 60}{sup -} negative ions and H{sub 2}{sup +}, H{sub 3}{sup +}, OH{sup +}, H{sub 2}O{sup +}, H{sub 3}O{sup +}, O{sub 2}{sup +} positive molecular ions were generated in this HCI-ECRIS. Without any major modification in the source and without any commonly applied tricks (such as usage of cesium or magnetic filter), negative ion beams of several {mu}A and positive molecular ion beams in the mA range were successfully obtained.

Ion hole formation and nonlinear generation of electromagnetic ion cyclotron waves: THEMIS observations

Science.gov (United States)

Shoji, Masafumi; Miyoshi, Yoshizumi; Katoh, Yuto; Keika, Kunihiro; Angelopoulos, Vassilis; Kasahara, Satoshi; Asamura, Kazushi; Nakamura, Satoko; Omura, Yoshiharu

2017-09-01

Electromagnetic plasma waves are thought to be responsible for energy exchange between charged particles in space plasmas. Such an energy exchange process is evidenced by phase space holes identified in the ion distribution function and measurements of the dot product of the plasma wave electric field and the ion velocity. We develop a method to identify ion hole formation, taking into consideration the phase differences between the gyromotion of ions and the electromagnetic ion cyclotron (EMIC) waves. Using this method, we identify ion holes in the distribution function and the resulting nonlinear EMIC wave evolution from Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. These ion holes are key to wave growth and frequency drift by the ion currents through nonlinear wave-particle interactions, which are identified by a computer simulation in this study.

Test de Rorscharch: respuestas diferenciales entre pacientes con y sin intento suicida

Directory of Open Access Journals (Sweden)

Alejandro Cuadra-Peralta

2009-12-01

Full Text Available Este estudio tuvo como objetivo identificar respuestas diferenciales entre grupos de No-pacientes, pacientes diagnosticados con Depresión, pacientes diagnosticados con Trastorno de Personalidad y con Depresión y pacientes con intento suicida a través de los indicadores de la Escala de Potencial suicida, propuesto por Passalacqua, Herrera y Orcoyen (1997. La muestra total fue de 70 sujetos de sexo femenino, con grupos de aproximadamente 18 personas cada uno. Se encontró diferencia significativa en seis indicadores entre los cuatro grupos y en diez indicadores entre los pacientes con intento suicida y los demás participantes. Con estos indicadores se realizó un análisis discriminante, encontrándose una alta capacidad para diferenciar los diferentes subgrupos, en especial a grupo de pacientes con intento suicida y el resto de las personas. Se entrega una formula para calcular la probabilidad de pertenencia al grupo de intento de suicidio.

Comparación de caracteres corporales y del veneno de Bothrops alternatus entre poblaciones de las provincias de Buenos Aires y Entre Ríos, Argentina

Directory of Open Access Journals (Sweden)

Rocco, Daniela Marisa

2011-11-01

Full Text Available Comparamos caracteres corporales y producción de veneno de ejemplares de Bothrops alternatus de una población aislada geográficamente (Olavarría, región de Tandilia, Buenos Aires con otra en su área de distribución continua de Concordia (Entre Ríos. Estudiamos el largo corporal, peso, separación entre dientes inoculadores, cantidad de veneno y de proteínas en el veneno por ejemplar. No se hallaron diferencias en los caracteres estudiados entre ambas poblaciones (p > 0.05. Las hembras fueron mayores que los machos en ambas muestras, entre un 12-18% (p 0.5; Olavarría: 142 ± 65 mg/animal, Concordia: 160 ± 80 mg/animal, aún ajustando la cantidad de veneno producida respecto al tamaño, mediante el cociente veneno/largo corporal (p >0.6. Tampoco hubo diferencias en el contenido proteico, siendo para ambas muestras de 0.697 ± 0.096 mg de proteínas/mg de veneno seco. Nuestros datos sugieren que los ejemplares de la población aislada de Tandilia no presentan variaciones en el tamaño corporal o en la cantidad de veneno producida, respecto a los ejemplares de Concordia. Some corporal characters and venom yield of adult specimens of Bothrops alternatus from the isolated region of Olavarría (Tandilian Region, Buenos Aires and the region of continuous distribution of Concordia (Entre Ríos were compared. Corporal length, weight, separation between fangs, venom yield by snake and the amount of protein in the venom were determined. No differences in the distinct characters from specimens from both regions were found (p > 0.05. Females were greater than males in both samples, 12-18% (p 0.5; Olavarría= 142 ± 65 mg / animal, Concordia= 161 ± 80 mg / animal even adjusting the venom yield with the corporal length by the relation mg of venom / corporal length (p > 0.6. No differences were observed in the protein content of the dry venom which was of 0.697 ± 0.096 mg of protein / mg of dry venom. From the study of these samples, it could be

Ion Dynamics at Shocks: Ion Reflection and Beam Formation at Quasi-perpendicular Shocks

International Nuclear Information System (INIS)

Kucharek, Harald; Moebius, Eberhard

2005-01-01

The physics of collisionless shocks is controlled by the ion dynamics. The generation of gyrating ions by reflection as well as the formation of field-aligned ion beams are essential parts of this dynamic. On the one hand reflection is most likely the first interaction of ions with the shock before they undergo the downstream thermalization process. On the other hand field-aligned ion beams, predominately found at the quasi-perpendicular bow shock, propagate into the distant foreshock region and may create wave activity. We revisit ion reflection, the source and basic production mechanism of field-aligned ion beams, by using multi-spacecraft measurements and contrast these observations with existing theories. Finally, we propose an alternative production mechanism

Generation and focusing of intense ion beams with an inverse pinch ion diode

International Nuclear Information System (INIS)

Hashimoto, Yoshiyuki; Sato, Morihiko; Yatsuzuka, Mitsuyasu; Nobuhara, Sadao

1992-01-01

Generation and focusing of ion beams using an inverse pinch ion diode with a flat anode has been studied. The ion beams generated with the inverse pinch ion diode were found to be focused at 120 mm from the anode by the electrostatic field in the diode. The energy and maximum current density of the ion beams were 180 keV and 420 A/cm 2 , respectively. The focusing angle of the ion beams was 4.3deg. The beam brightness was estimated to be 1.3 GW/cm 2 ·rad 2 . The focusing distance of the ion beams was found to be controllable by changing the diameters of the anode and cathode. (author)

Fatores associados à Síndrome de Burnout entre profissionais intensivistas de hospital universitário.

Directory of Open Access Journals (Sweden)

Claidson Felipe Campanha ALKIMIM

2015-02-01

Full Text Available Objetivo: Avaliar prevalências da Síndrome de Burnout (SB e dimensões -exaustão emocional (EE, despersonalização (DE e baixa realização profissional (BRP- entre profissionais intensivistas e identificar suas associações com variáveis individuais, ocupacionais e organizacionais. Métodos: Estudo analítico entre intensivistas de hospital universitário de Montes Claros-MG. Utilizou-se para coleta de dados Maslach Burnout Inventory, Critério de Classificação Econômica Brasil e questionário “variáveis individuais, ocupacionais e organizacionais”. Resultados: As prevalências da SB e dimensões (EE-DE-BRP foram respectivamente: 34,0%; 16,9%; 19,4% e 17,9%. Por análise multivariada registrou-se maior chance de desenvolver SB entre homens às mulheres; pessoas que identificam o trabalho como “às vezes/quase sempre/sempre” estressante àquelas que o identificam como “nunca/quase nunca” estressante; e pessoas que “não concordam e nem discordam/concordam em parte/concordam totalmente” que escolheriam outra profissão com a mesma remuneração àquelas que “discordam totalmente/em parte” na escolha de outra profissão. Maior chance de desenvolver EE: entre “solteiros/divorciados/desquitados” aos casados; entre os que têm “ruim/regular” motivação com o trabalho àqueles cuja motivação é “boa/muito boa/excelente”; e entre aqueles que percebem que “às vezes/quase sempre/sempre” as pessoas são tratadas desigualmente àqueles que percebem que “nunca/quase nunca” existe tratamento desigual. Maior chance de desenvolver DE: entre aqueles que “nunca consumiram bebida alcóolica” àqueles que “consomem/não consomem mais”; e entre aqueles com “ruim/regular” expectativa profissional àqueles com expectativa “boa/muito boa/excelente”. Conclusão: As prevalências registradas são preocupantes sendo que SB e dimensão DE associaram-se às variáveis individuais e ocupacionais e EE

Behaviour of tetraalkylammonium ions in high-field asymmetric waveform ion mobility spectrometry.

Science.gov (United States)

Aksenov, Alexander A; Kapron, James T

2010-05-30

High-field asymmetric waveform ion mobility spectrometry (FAIMS) is an ion-filtering technique recently adapted for use with liquid chromatography/mass spectrometry (LC/MS) to remove interferences during analysis of complex matrices. This is the first systematic study of a series of singly charged tetraalkylammonium ions by FAIMS-MS. The compensation voltage (CV) is the DC offset of the waveform which permits the ion to emerge from FAIMS and it was determined for each member of the series under various conditions. The electrospray ionization conditions explored included spray voltage, vaporizer temperature, and sheath and auxiliary gas pressure. The FAIMS conditions explored included carrier gas flow rate, electrode temperature and composition of the carrier gas. Optimum desolvation was achieved using sufficient carrier gas (flow rate > or = 2 L/min) to ensure stable response. Low-mass ions (m/z 100-200) are more susceptible to changes in electrode temperature and gas composition than high mass ions (m/z 200-700). As a result of this study, ions are reliably analyzed using standard FAIMS conditions (dispersion voltage -5000 V, carrier gas flow rate 3 L/min, 50% helium/50%nitrogen, inner electrode temperature 70 degrees C and outer electrode temperature 90 degrees C). Variation of FAIMS conditions may be of great use for the separation of very low mass tetraalkylammonium (TAA) ions from other TAA ions. The FAIMS conditions do not appear to have a major effect on higher mass ions. Copyright 2010 John Wiley & Sons, Ltd.

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes

KAUST Repository

Geise, Geoffrey M.

2014-08-26

© the Partner Organisations 2014. Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The

Observations of strong ion-ion correlations in dense plasmas

Energy Technology Data Exchange (ETDEWEB)

Ma, T.; Fletcher, L.; Pak, A.; Chapman, D. A.; Falcone, R. W.; Fortmann, C.; Galtier, E.; Gericke, D. O.; Gregori, G.; Hastings, J.; Landen, O. L.; Le Pape, S.; Lee, H. J.; Nagler, B.; Neumayer, P.; Turnbull, D.; Vorberger, J.; White, T. G.; Wünsch, K.; Zastrau, U.; Glenzer, S. H.; Döppner, T.

2014-05-01

Using simultaneous spectrally, angularly, and temporally resolved x-ray scattering, we measure the pronounced ion-ion correlation peak in a strongly coupled plasma. Laser-driven shock-compressed aluminum at ~3× solid density is probed with high-energy photons at 17.9 keV created by molybdenum He-α emission in a laser-driven plasma source. The measured elastic scattering feature shows a well-pronounced correlation peak at a wave vector of k=4k=4Å-1. The magnitude of this correlation peak cannot be described by standard plasma theories employing a linear screened Coulomb potential. Advanced models, including a strong short-range repulsion due to the inner structure of the aluminum ions are however in good agreement with the scattering data. These studies have demonstrated a new highly accurate diagnostic technique to directly measure the state of compression and the ion-ion correlations. We have since applied this new method in single-shot wave-number resolved S(k) measurements to characterize the physical properties of dense plasmas.

Reduced-portion entrées in a worksite and restaurant setting: impact on food consumption and waste.

Science.gov (United States)

Berkowitz, Sarah; Marquart, Len; Mykerezi, Elton; Degeneffe, Dennis; Reicks, Marla

2016-11-01

Large portion sizes in restaurants have been identified as a public health risk. The purpose of the present study was to determine whether customers in two different food-service operator segments (non-commercial worksite cafeteria and commercial upscale restaurant) would select reduced-portion menu items and the impact of selecting reduced-portion menu items on energy and nutrient intakes and plate waste. Consumption and plate waste data were collected for 5 weeks before and 7 weeks after introduction of five reduced-size entrées in a worksite lunch cafeteria and for 3 weeks before and 4 weeks after introduction of five reduced-size dinner entrées in a restaurant setting. Full-size entrées were available throughout the entire study periods. A worksite cafeteria and a commercial upscale restaurant in a large US Midwestern metropolitan area. Adult worksite employees and restaurant patrons. Reduced-size entrées accounted for 5·3-12·8 % and 18·8-31·3 % of total entrées selected in the worksite and restaurant settings, respectively. Food waste, energy intake and intakes of total fat, saturated fat, cholesterol, Na, fibre, Ca, K and Fe were significantly lower when both full- and reduced-size entrées were served in the worksite setting and in the restaurant setting compared with when only full-size entrées were served. A relatively small proportion of reduced-size entrées were selected but still resulted in reductions in overall energy and nutrient intakes. These outcomes could serve as the foundation for future studies to determine strategies to enhance acceptance of reduced-portion menu items in restaurant settings.

Variabilidad espacial y temporal de larvas de jurel Trachurus murphyien el Perú entre 1966 –2010

Directory of Open Access Journals (Sweden)

Patricia Ayón

2013-10-01

Full Text Available El análisis espacial y temporal de larvas de jurel Trachurus murphyien el mar peruano entre los años 1966 y 2010 confirma su presencia constante durante todo el periodo estudiado. En general, en este periodo la abundancia de larvas de jurel T. murphyimuestra una tendencia ligeramente ascendente destacándose cambios en la distribución espacial y una alta variabilidad interanual, con cortos periodos de alta abundancia promedio, intercalados con periodos más prolongados y de baja abundancia. El promedio anual estimado varió entre 3 y 79 larvas/ m2 . La distribución espacial presentó tres periodos importantes: uno con mayores densidades de larvas al sur de los 14°S, entre 1970 y 1979; cambió hacia el norte de esta latitud, entre 1980 y 1999; y otro de mayor densidad al sur de los 18°S, en el último periodo 2000 – 2010. Los centros de gravedad de la distribución de larvas presentaron tres periodos muy notorios: fueron más costeros hacia el sur de los 14°S, entre 1966 y1978; más oceánicos y al norte de los 14°S, entre 1979 y 1994; y con una posición intermedia entre 1995 – 2010. Se discute la relación entre la distribución de las larvas con las variables oceanográficas y la distribución de T. murphyiadultos y juveniles, además se destaca que el mar del Perú es un centro principal y permanente de actividad reproductiva de esta especie.

Convergencias y divergencias entre los sistemas interamericano y el europeo de derechos humanos

OpenAIRE

Gasparoto, Ana Lucía

2014-01-01

Este trabajo tiene la finalidad de puntear las convergencias y las divergencias existentes entre la Corte Interamericana de Derechos Humanos y el Tribunal Europeo de Derechos Humanos, encima con la adopción del Protocolo 11 del Convenio Europeo para la Protección de los Derechos Humanos y las Libertades Fundamentales y su impacto en el Sistema Europeo de Derechos Humanos. Igualmente se analisa las relaciones entre las dos Cortes.

New experimental initiatives using very highly charged ions from an 'electron beam ion trap'

International Nuclear Information System (INIS)

Schneider, D.

1996-01-01

A short review of the experimental program in highly-charged heavy ion physics conducted at the Lawrence Livermore National Laboratory Electron Beam Ion Trap (EBIT) facility is presented. The heavy-ion research, involving ions up to fully stripped U 92+ , includes precision x-ray spectroscopy and lifetime studies, electron impact ionization and excitation cross section measurements. The investigations of ion-surface interactions following the impact of high-Z highly charged ions on surfaces are aimed to study the neutralization dynamics effecting the ion and the response of the surface as well. (author)

Development of exploding wire ion source for intense pulsed heavy ion beam accelerator

International Nuclear Information System (INIS)

Ochiai, Y.; Murata, T.; Ito, H.; Masugata, K.

2012-01-01

A Novel exploding wire type ion source device is proposed as a metallic ion source of intense pulsed heavy ion beam (PHIB) accelerator. In the device multiple shot operations is realized without breaking the vacuum. The basic characteristics of the device are evaluated experimentally with an aluminum wire of diameter 0.2 mm, length 25 mm. Capacitor bank of capacitance 3 μF, charging voltage 30 kV was used and the wire was successfully exploded by a discharge current of 15 kA, rise time 5.3 μs. Plasma flux of ion current density around 70 A/cm 2 was obtained at 150 mm downstream from the device. The drift velocity of ions evaluated by a time-of-flight method was 2.7x10 4 m/sec, which corresponds to the kinetic energy of 100 eV for aluminum ions. From the measurement of ion current density distribution ion flow is found to be concentrated to the direction where ion acceleration gap is placed. From the experiment the device is found to be acceptable for applying PHIB accelerator. (author)

An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy

Energy Technology Data Exchange (ETDEWEB)

Cao, Yun, E-mail: caoyun@impcas.ac.cn; Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia [Institute of Modern Physics, CAS, Lanzhou 730000 (China)

2014-02-15

A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C{sup 5+} ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C{sup 5+} ion beam was got when work gas was CH{sub 4} while about 262 eμA of C{sup 5+} ion beam was obtained when work gas was C{sub 2}H{sub 2} gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

Recent advances in high current vacuum arc ion sources for heavy ion fusion

CERN Document Server

Qi Nian Sheng; Prasad, R R; Krishnan, M S; Anders, A; Kwan, J; Brown, I

2001-01-01

For a heavy ion fusion induction linac driver, a source of heavy ions with charge states 1+-3+, approx 0.5 A current beams, approx 20 mu s pulse widths and approx 10 Hz repetition rates is required. Thermionic sources have been the workhorse for the Heavy Ion Fusion (HIF) program to date, but suffer from heating problems for large areas and contamination. They are limited to low (contact) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states in short and long pulse bursts and high beam current density. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications was investigated. We have modifie...

Anomalous surface behavior of hydrated guanidinium ions due to ion pairing

Science.gov (United States)

Ekholm, Victor; Vazdar, Mario; Mason, Philip E.; Bialik, Erik; Walz, Marie-Madeleine; Öhrwall, Gunnar; Werner, Josephina; Rubensson, Jan-Erik; Jungwirth, Pavel; Björneholm, Olle

2018-04-01

Surface affinity of aqueous guanidinium chloride (GdmCl) is compared to that of aqueous tetrapropylammonium chloride (TPACl) upon addition of sodium chloride (NaCl) or disodium sulfate (Na2SO4). The experimental results have been acquired using the surface sensitive technique X-ray photoelectron spectroscopy on a liquid jet. Molecular dynamics simulations have been used to produce radial distribution functions and surface density plots. The surface affinities of both TPA+ and Gdm+ increase upon adding NaCl to the solution. With the addition of Na2SO4, the surface affinity of TPA+ increases, while that of Gdm+ decreases. From the results of MD simulations it is seen that Gdm+ and SO4 2 - ions form pairs. This finding can be used to explain the decreased surface affinity of Gdm+ when co-dissolved with SO4 2 - ions. Since SO4 2 - ions avoid the surface due to the double charge and strong water interaction, the Gdm+-SO4 2 - ion pair resides deeper in the solutions' bulk than the Gdm+ ions. Since TPA+ does not form ion pairs with SO4 2 -, the TPA+ ions are instead enriched at the surface.

Energy landscapes for mobile ions in ion conducting solids

Indian Academy of Sciences (India)

molecular dynamics (MD) simulations yields quantitative predictions of the ion transport characteristics. As ... Solid electrolytes; bond valence analysis; ion transport in glasses. 1. .... clusters are considered to contribute only to a.c. conduc-.

Das vizinhanças entre o feminino e a loucura

Directory of Open Access Journals (Sweden)

Elizabeth Cristina Landi

Full Text Available O tema da loucura feminina se apresenta frequentemente na clínica psicanalítica por meio de sujeitos neuróticos. Questiona-se neste artigo as proximidades entre psicose e a loucura que se apresenta no discurso das mulheres neuróticas. As identificações iniciais, por meio das quais a criança se aliena ao desejo do Outro, determinam certa loucura, não restrita apenas aos psicóticos. Para um sujeito do sexo feminino, que passa pelo tortuoso processo de tornar-se mulher, a loucura é uma possibilidade, pois uma mulher, por encontrar-se dividida entre o gozo masculino e o feminino, se aproxima da loucura, mas é não louca-de-todo.

DETERMINATION OF STRONTIUM IONS IN WATERS WITH A HIGH CONTENT OF SODIUM IONS

Directory of Open Access Journals (Sweden)

Tatiana Mitina

2015-06-01

Full Text Available This paper reports on the influence of sodium ions on experimental determination of strontium ions concentration in waters with a high content of sodium ions by using emission flame photometry and atomic absorption spectroscopy. For the method of emission flame photometry it was shown that at a wavelength of 460.7 nm (spectral emission line of strontium the emission is linearly dependent on the concentration of sodium ions. The greatest impact of high concentrations of sodium ions on the result of determination the strontium ions concentration has been registered at low levels of strontium. The influence of nitric acid on the results is also discussed. In the case of using atomic absorption spectroscopy method no influence of sodium ions and nitric acid on the results of determination the strontium ions concentration was revealed. The metrological characteristics of both methods are evaluated.

An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

Energy Technology Data Exchange (ETDEWEB)

Thopan, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuldyuld@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2013-07-15

Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

International Nuclear Information System (INIS)

Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L.D.

2013-01-01

Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells

Genes candidatos para la comorbilidad entre trastornos de ansiedad y trastornos adictivos.

OpenAIRE

Gallego Moreno, Xavier

2008-01-01

Esta Tesis Doctoral ha consistido en el estudio de los mecanismos implicados en la comorbilidad entre el abuso de drogas y los trastornos de ansiedad, así como en las regiones cerebrales responsables de la coexistencia de estos dos trastornos en modelos transgénicos. Nos hemos centrado en dos grandes familias de genes, que podrían actuar como interfaz genético en la comorbilidad entre trastornos de ansiedad y de abuso de sustancias: neurotrofinas por su intervención en el neurodesarrollo y en...

Pulsed, Inductively Generated, Streaming Plasma Ion Source for Heavy Ion Fusion Linacs

International Nuclear Information System (INIS)

Steven C. Glidden; Howard D Sanders; John B. Greenly; Daniel L. Dongwoo

2006-01-01

This report describes a compact, high current density, pulsed ion source, based on electrodeless, inductively driven gas breakdown, developed to meet the requirements on normalized emittance, current density, uniformity and pulse duration for an ion injector in a heavy-ion fusion driver. The plasma source produces >10 (micro)s pulse of Argon plasma with ion current densities >100 mA/cm2 at 30 cm from the source and with strongly axially directed ion energy of about 80 eV, and sub-eV transverse temperature. The source has good reproducibility and spatial uniformity. Control of the current density during the pulse has been demonstrated with a novel modulator coil method which allows attenuation of the ion current density without significantly affecting the beam quality. This project was carried out in two phases. Phase 1 used source configurations adapted from light ion sources to demonstrate the feasibility of the concept. In Phase 2 the performance of the source was enhanced and quantified in greater detail, a modulator for controlling the pulse shape was developed, and experiments were conducted with the ions accelerated to >40 kV

La problematica de la demarcacion entre ciencia y pseudociencia y sus implicaciones en la educacion cientifica

Science.gov (United States)

Jimenez Tolentino, Dinorah

2011-12-01

En la sociedad prevalece una tendencia generalizada hacia la inclusion de creencias y practicas pseudocientificas. Esta investigacion responde a la necesidad de analizar como la proliferacion de las pseudociencias afecta la vision que tienen los estudiantes universitarios sobre las ciencias naturales. A tales efectos, la investigadora describe las concepciones epistemologicas que tienen los estudiantes sobre las ciencias y las pseudociencias e identifica los criterios de demarcacion, entre un area y otra, que se derivan de estas concepciones. De igual modo, esta identifica las creencias y practicas pseudocientificas de mayor arraigo entre los estudiantes, destacando, a su vez, la razon de ser de las mismas. Por ultimo, la investigadora analiza las implicaciones educativas de la problematica de la demarcacion entre ciencia y pseudociencia. La investigacion es de naturaleza mixta, enmarcada en los paradigmas empirico- analitico y cualitativo. El proceso investigativo se llevo a cabo mediante la administracion del cuestionario Criterios para la demarcacion entre ciencia y pseudociencia. La parte cualitativa estuvo enmarcada en el diseno de estudio de caso, recopilando informacion mediante entrevistas semiestructuradas en dos grupos focales. La poblacion de estudio estuvo constituida por estudiantes universitarios del nivel subgraduado de la Universidad Central de Bayamon. Los resultados del estudio reflejaron las concepciones erroneas de los estudiantes sobre la naturaleza de las ciencias y las pseudociencias. Con respecto a la demarcacion entre ciencia y pseudociencia, el criterio imperante entre los universitarios es el de la verificabilidad, considerando la aplicacion del metodo cientifico como el metodo para demostrar la veracidad de las teorias cientificas. Las creencias y practicas pseudocientificas no son muy frecuentes entre los universitarios. Estos atribuyen las mismas a la prevalencia de elementos supersticiosos y al engano a que es sometida la poblacion

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1985-01-01

Ion-Selective Electrode Reviews, Volume 7 is a collection of papers that covers the applications of electrochemical sensors, along with the versatility of ion-selective electrodes. The coverage of the text includes solid contact in membrane ion-selective electrodes; immobilized enzyme probes for determining inhibitors; potentiometric titrations based on ion-pair formation; and application of ion-selective electrodes in soil science, kinetics, and kinetic analysis. The text will be of great use to chemists and chemical engineers.

RELAÇÕES ENTRE ENSINO E APRENDIZAGEM NA EJA

Directory of Open Access Journals (Sweden)

José Moisés Nunes da Silva

2010-01-01

Full Text Available Este artigo tem por objetivo apresentar uma distinção clara e objetiva entre os processos de ensinar e aprender. Nessa perspectiva, primeiramente destaca a educação no contexto e como parte integrante dos processos de transformações do mundo contemporâneo. Em seguida, sustentado por diversos autores, discute-se a distinção entre ensinar e aprender. Espera-se contribuir para uma reflexão sobre a prática pedagógica docente e da necessidade de melhoria do processo de ensino e aprendizagem a fim de possibilitar uma educação em consonância com a concepção de formação integral do cidadão, à medida que tal distinção seja introjetada pelos professores. PALAVRAS-CHAVE: Ensinar. Aprender. Aprendizagem do jovem e do adulto.

Observation of ion-acoustic rarefaction solitons in a multicomponent plasma with negative ions

International Nuclear Information System (INIS)

Ludwig, G.O.; Ferreira, J.L.; Nakamura, Y.

1984-01-01

The propagation of ion-acoustic solitons in a plasma with negative ions has been observed. For sufficiently large concentration of negative ions, applied rarefactive (negative) voltage pulses break up into solitons, whereas compressive pulses evolve into wave trains, with exactly the opposite behavior as that for a plasma composed only of positive ions. There is a critical value of the negative-ion concentration for which a finite-amplitude pulse propagates without steepening

High charge state metal ion production in vacuum arc ion sources

International Nuclear Information System (INIS)

Brown, I.G.; Anders, A.; Anders, S.

1994-01-01

The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle or order 1% and operation of a dc embodiment has been demonstrated also. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with peak (pulsed) beam current up to several amperes. The ion charge state distribution has been extensively studied. Ion spectra have been measured for a wide range of metallic cathode materials, including Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U, as well as compound and alloy cathode materials such as TiC, SiC, UC, PbS, brass, and stainless steel. The ions generated are in general multiply-stripped with a mean charge state of from 1 to 3, depending on the particular metal species, and the charge state distribution can have components from Q = 1+ to 6+. Here the authors review the characteristics of vacuum arc ion sources from the perspective of their high charge state metal ion production

Utilization of ion source 'SUPERSHYPIE' in the study of low energy ion-atom and ion-molecule collisions

International Nuclear Information System (INIS)

Bazin, V.; Boduch, P.; Chesnel, J.Y.; Fremont, F.; Lecler, D.; Pacquet, J. Y.; Gaubert, G.; Leroy, R.

1999-01-01

Modifications in the ECR 4M ion source are described, which conducted to realization of the advanced source 'SUPERSHYPIE'. The Ar 8+ ion collision with Cs(6s,6p) were studied by photon spectroscopy at low energy, where the process is dominated by simple electron capture. Results obtained with 'SUPERSHYPIE' source are presented. The source was utilized also in ion-molecule collisions (CO, H 2 ) to study the spectra of recoil ions and Auger electron spectra in the Ar 17+ He collisions. The excellent performances of 'SUPERSHYPIE' in high charge production and concerning its accurate and fine control and stability are illustrated and underlined as compared with those of ECR 4M source

Complexation ion-exchange chromatography of some metal ions on papers impregnated with Ti(IV)-based inorganic ion exchangers.