[en] This thesis aims at characterizing the dynamics of fast electrons generated by the Landau absorption of the hybrid wave and studying their effects on electron cyclotron radiation. The different processes involved in the propagation and resonant absorption of the hybrid wave in plasmas are described. A method such as ray-tracing allows the characterization of the dynamics of heating but this method relies on the hypothesis of geometrical optics. Whenever absorption rate is low as it is in Tore-Supra, the hybrid wave undergoes a series of successive reflections on the edge of the plasma before being completely absorbed. These reflections generate an electromagnetic chaos in which geometrical optics hypothesis are no longer valid. A statistical treatment of the Fokker-Planck equation allows the calculation of the mean distribution function of electrons in the plasma submitted to hybrid wave. The electron cyclotron radiation is then deduced and by assuming that plasma behaves like a black body, a theoretical radiative temperature is calculated. The confrontation of this theoretical temperature profile with experimental values allows the validation of this modeling and the estimation of the effects of fast electrons on temperature measurements. (A.C.)

[en] In this work, by means of an exhaustive bibliographical revision and in a methodical way, they seek to settle down, the characteristics of the catalysts for Hydro treatment (HDT) on those that it is necessary to act with the purpose of obtaining more active, selective and resistant catalysts to the deactivation

[en] This report shows the mobile units for hydro geochemical studies. The authors analyze the work of mobile unit and the cars that conform the unit: Sampling car and analysis car: The sampling and equipment are took into account as well

[en] Currently the project is in its final part documentary level was achieved by passing the PAT (acceptance test procedure) approved by Oskarshamn and ending once the body Swedish qualification, SQC, review, send your comments and after evaluation, approve all documentation.

[en] The Working Group on Digital Mammography created by the Spanish Medical Physics Society is involved in the elaboration of a specific protocol for the digital mammographic systems. The protocol is based on the results obtained in a survey of the currently digital systems found in our country. This work is focused on the results related to the image quality and dose obtained with four flat panel (FP) detectors and four CR detectors. The image quality was evaluated with the CDMAM phantom and doses values at clinical conditions were obtained for PMMA thicknesses comprises between 2 and 7 cm. The detection thresholds derived from the CDMAM images were in general lower for the FP systems. In a first approximation we have compared our results with the tolerances proposed in the Addendum on digital mammography to the European Guidelines. We have found that detection thresholds determined with the FP systems accomplished well the tolerance proposed in the Guidelines. By contrast, some CR systems do not fit these tolerance. Mean glandular doses associated with the dosimetric standard phantom (4,5 cm PMMA) were 42% higher for the CR systems. This value could be a 150% higher for thicker PMMA thicknesses. (Author)

[en] It is proposed to develop a method to judge the certainty on the information regarding to deoxidation equilibria of iron melts. To accomplish this objective, thermochemical data was collated and then evaluated. The basic knowledge on deoxidation conditions are framed by the non-ideal Henrian behaviour of diluted solutions of both de oxidizer and oxygen in liquid iron in equilibrium with a pure oxide. Conventional deoxidation reactions were considered at 1,873 K such that in their equilibrium constants, only first order interaction coefficients were considered. The criteria in selecting the most appropriated free energy equation was based on evaluating them under two critical composition points: 1 where they satisfy an oxygen to de oxidizer ratio dictated by its stoichiometry and 2 where oxygen contents at a given amount of de oxidizer reaches a minimum value. These data were plotted on logarithmic scales to appreciate the effects of de oxidizers valences. Once such information was classified, under restrictions 1 and 2, previous compositions were related to de oxidizers electronegativities. (Author) 36 refs

[en] Tecnatom development in the past with ultrasonic inspection procedures to examine vessels BWR of several Central nuclear (CRDH) control rod drive elements, accommodations. In each case, inspection techniques have relied on both the volume of required test postulated defects. Also, taking into account the possible access to the component, developed mechanical equipments of different characteristics.

[en] The adsorption of benzotriazole (BTA) on copper surfaces in 0.001, 0.005 and 0.01 M concentrations of sulphuric acid was investigated using gravimetric measurements. BTA was tested in concentrations from 1x10''-5 to 1x10''-1 M at temperatures from 298 to 328 K. The adsorption mechanism is discussed in terms of applicability of the conventional Frumkin, Bockris-Swinkels and Kastening-Holleck isotherms, among others. The best fit was obtained using the Frumkin isotherm model. the projected molecular area of BTA was calculated to elucidate inhibitor orientation in the adsorption process. (Author) 38 refs

[en] The characterisation of the hydrogeochemical parameters controlling the radionuclide migration towards the biosphere implicates the development of a methodology including instrumentation and equipment for working in deep boreholes, according with the data in which we are more interested. This methodology consists of a systematic and detailed study of the boreholes (studies on the cores, geophysical parameters, hydraulic tests...) that allows to select zones for water sampling and characterisation. The selected areas are adequately isolated with a double packer system and coupled instrumentation for pumping water (pumps or gas lift systems). The isolated zone is cleaned by pumping, and the tracer concentration, tritium measures or the control of the stabilization of physico-chemical parameters, are good indicators of the representativity of the sample. Water, gases, particles, colloids and microorganisms sampling is made in glove boxes and the analysis are made in a mobile laboratory in situ for determining the more sensible parameters, avoiding the sample alterations with the transport. (Author) 18 refs

[en] Mineral alteration processes give raise to the physico-chemical characteristics of natural waters by means of water-rock interactions during the hydrogeological cycle. Rainwater acquire their main components by exchange ions with the cation exchange complex of the insaturated zone. The superficial alteration of the primary rocks origins the secondary minerals and remain reflected in the solutes incorporation in the waters. The origin of groundwaters composition from igneous rocks would be predicted with chemical cuantitative models if thermodynamic constants of some alteration products would be known. The sulfide oxidation and the sulphate reduction are two important redox hydrogeochemical processes involved in the changes of the redox potential and the bacteries are present as catalytic of the reactions. The dolomite formation and the dedolomization are present in the limestones and several problems appear with the kinetic in the reaction of the dolomite formation