Dispositifs architecturaux et expérience spatiale de la ville: le cas de l'installation architecturale

L’installation architecturale, l’objet de recherche central de cette thèse, est un type d’intervention architecturale qui échappe autant au discours professionnel qu’à celui des chercheurs en architecture lorsqu’il s’agit de définir les limites de la profession et celles de la discipline. Prenant ses distances avec le déterminisme fonctionnaliste qui domine la pensée et la pratique courantes de l’architecture, la recherche a pour but de montrer que l’installation architecturale s’inscrit dans une tradition classique bien ancrée dans la pratique et dans la théorie de l’architecture et que son rôle dans la pensée sur le projet architectural et urbain de la ville contemporaine a occupé et occupe encore une place importante. C’est pour ces raisons que la recherche se présente essentiellement comme une exploration guidée avant tout par le souci de contribuer à la reconnaissance de cette pratique particulière de l’architecture. Avant de poser l’hypothèse de recherche, nous avons présumé que l’installation architecturale agit comme une construction active dans l’espace public, qu’elle comble certains manques quant à la définition des enjeux urbains de la ville contemporaine, particulièrement dans un contexte où les libertés de choix, de mouvances et d’opportunités sont largement accompagnés par des stratégies d’organisation, de contrôle public et de constructions technologiques, d’efficacité énergétique et fonctionnelle. La recherche a également supposé que cette valeur d’agitation sociale et culturelle est liée à certaines caractéristiques inhérentes à l’architecture, à la ville et à l’individu et qu’elle représente, par le fait même, un objet de recherche important tout en offrant une porte d’entrée dans les questions plus larges qui traversent la discipline. Parmi celles-ci sont particulièrement étudiés des pratiques et des discours qui échappent aux définitions usuelles et qui offrent un regard critique quant aux limites de la discipline, des pratiques qui mettent en lumière des idées telles que l’instable et l’événement, des notions d’intervention et d’éthique, d’action et d’exploration. Cette thèse cherche ainsi à éclairer la contribution potentielle de l’installation architecturale dans les problématiques urbaines et architecturales et de montrer comment l’expérience de la ville à travers le dispositif architectural peut transformer nos manières d’aborder l’espace construit.

Exposition au bruit dans une installation gazière

L'étude vise à évaluer l'exposition professionnelle au bruit des travailleurs d'une plateforme gazière en Algérie et à mettre en évidence des déterminants influençant cette exposition. Des groupes d'exposition homogène (GEH) ont été constitués sur la base de ressemblances quant à l'exposition au bruit, aux titres d'emploi et aux lieux de travail. Deux stratégies d'échantillonnage ont été suivies, la première selon la norme internationale ISO 9612 : 2009 et la seconde selon la stratégie aléatoire de l'AIHA. Pour les deux approches, les niveaux de bruit (Lex, 8h, niveaux d'exposition au bruit pondéré (A) ajustés à une journée de travail de 8 heures) des opérateurs et des superviseurs étaient généralement > 85 dB(A) alors que pour les techniciens-tableau, les niveaux de bruit (Lex, 8h) étaient en tout temps < 85 dB(A). Pour les trois GEH du titre d'emploi des maintenanciers, il y a eu régulièrement des dépassements de la valeur de référence. Plusieurs travailleurs oeuvrant sur les plateformes gazières sont exposés à des niveaux importants de bruit et sont à risque de développer des problèmes auditifs.

Étude des caractéristiques et du processus de scénarisation d'une installation interactive

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

The Role of Diffusion in ISOL Targets for the Production of Radioactive Ion Beams

On line isotope separation techniques (ISOL) for production of ion beams of short-lived radionuclides require fast separation of nuclear reaction products from irradiated target materials followed by a transfer into an ion source. As a first step in this transport chain the release of nuclear reaction products from refractory metals has been studied systematically and will be reviewed. High-energy protons (500 - 1000 MeV) produce a large number of radionuclides in irradiated materials via the nuclear reactions spallation, fission and fragmentation. Foils and powders of Re, W, Ta, Hf, Mo, Nb, Zr, Y, Ti and C were irradiated with protons (600 - 1000 MeV) at the Dubna synchrocyclotron, the CERN synchrocyclotron and at the CERN PS-booster to produce different nuclear reaction products. The main topic of the paper is the determination of diffusion coefficients of the nuclear reaction products in the target matrix, data evaluation and a systematic interpretation of the data. The influence of the ionic radius of the diffusing species and the lattice type of the host material used as matrix or target on the diffusion will be evaluated from these systematics. Special attention was directed to the release of group I, II and III-elements. Arrhenius plots lead to activation energies of the diffusion process.

How about a visual lecture? : viewers' interpretations of a visual-pedagogical installation challenging family photography. '¿Qué tal una clase visual? : las interpretaciones de los espectadores de una instalación visual-pedagógica que cuestiona la fotografía de familia'.

Resumen basado en el de la publicación

Musealising hope: reflections on the saga of an artistic installation of human solidarity

“Musealising hope” reflects on the trials and tribulations of an installation designed as a tribute to the struggle for survival of African peoples who dare make the long trek to Europe by sea. Its accomplishment involved a number of players whose conduct and reactions to events bear witness to the manner in which artists, the media, heads of cultural institutions, museologists, welfare institutions, and politicians cope with the phenomenon of immigration and with our present-day multicultural societies. In turn, this artistic endeavour and its symbolic signification highlight the changes which art and culture have undergone over the past few years and the kind of transformation which new inter-ethnic communities have brought to bear on concepts such as national heritage, identity or memory.

Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant

In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by U-238 and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (<= 8.8 Bq/g) of U-238 Were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (<= 11 Bq/g) of Ra-226 were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution. (c) 2005 Elsevier Ltd. All rights reserved.

Industrial radioactive barite scale: suppression of radium uptake by introduction of competing ions

Incorporation of radioactive isotopes during the formation of barite mineral scale is a widespread phenomenon occurring within the oil, mining and process industries. In a series of experiments radioactive barite/celestite solid solutions (SSBarite-Celcstite) have been synthesized under controlled conditions by the counter diffusion of Ra-226, Ba2+, Sr24+ and SO42- ions through a porous medium (silica gel), to investigate inhibiting effects in Ra uptake associated with the introduction of a competing ion (Sr2+). From characterization studies, the particle size and the morphology of the crystals appear to be related to the initial [Sr]/[Ba] molar ratio of the starting solution. Typically, systems richer in Sr produce smaller sized crystals and clusters characterized by a lower degree of order. The activity introduced to the system is mainly incorporated in the crystals generated from the barite/celestite solid solution as suggested by the activity profiles of the hydrogel columns analysed by gamma-spectrometry. There is a relationship between the initial [Sr]/[Ba] molar ratio of the starting solution and the activity exhibited by the synthesized crystals. An effective inhibition of the Ra-226 uptake during formation of the crystals (SSBarite-Celestite) was obtained through the introduction of a competing ion (Sr2+): the higher the initial [Sr]/[Ba] molar ratio of the starting solution, the lower the intensity of the activity peak in the crystals. (C) 2003 Published by Elsevier Ltd.

Extraction behavior of the synergistic system 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine and 2-bromodecanoic acid using Am and Eu as radioactive tracers

In this study, the extraction properties of a synergistic system consisting of 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine (BODO) and 2-bromodecanoic acid (HA) in tert-butyl benzene (TBB) have been investigated as a function of ionic strength by varying the nitrate ion and perchlorate ion concentrations. The influence of the hydrogen ion concentration has also been investigated. Distribution ratios between 0.03-12 and 0.003-0.8 have been found for Am(III) and Eu(HI), respectively, but there were no attempts to maximize these values. It has been shown that the distribution ratios decrease with increasing amounts of ClO4-, NO3-, and H+. The mechanisms, however, by which the decrease occurs, are different. In the case of increasing perchlorate ion concentration, the decrease in extraction is linear in a log-log plot of the distribution ratio vs. the ionic strength, while in the nitrate case the complexation between nitrate and Am or Eu increases at high nitrate ion concentrations and thereby decreases the distribution ratio in a non-linearway. The decrease in extraction could be caused by changes in activity coefficients that can be explained with specific ion interaction theory (SIT); shielding of the metal ions, and by nitrate complexation with Am and Eu as competing mechanism at high ionic strengths. The separation factor between Am and Eu reaches a maximum at similar to1 M nitrate ion concentration. Thereafter the values decrease with increasing nitrate ion concentrations.

Carbon-encapsulated radioactive Tc-99m nanoparticles

A macroscopic quantity of quasi-spherical fullerene-like shells (see Figure) that encapsulate iron nanoparticles containing radioisotope Tc-99m are prepared for the first time. The nanocomposite is acid-non-leachable, retaining radioactivity at an extremely high level. This method will enable rigorous studies of what are currently theoretical descriptions of nanometer-scale medicinal delivery vehicles for diagnostic and therapeutic purposes.

Characterisation of soils containing naturally occurring radioactive material (NORM) using in situ and rapid laboratory techniques. Case study: South Terras, Cornwall

In situ analysis has become increasingly important for contaminated land investigation and remediation. At present, portable techniques are used mainly as scanning tools to assess the spread and magnitude of the contamination, and are an adjunct to conventional laboratory analyses. A site in Cornwall, containing naturally occurring radioactive material (NORM), provided an opportunity for Reading University PhD student Anna Kutner to compare analytical data collected in situ with data generated by laboratory-based methods. The preliminary results in this paper extend the author‟s poster presentation at last September‟s GeoSpec2010 conference held in Lancaster.