A CONTROL SYSTEM FOR CRYOGENIC INSTALLATIONS

Un système de contrôle modulaire a été développé pour l'automatisation des systèmes cryogéniques. Le système est bâti autour d'un microprocesseur ; on a développé des cartes d'interface conventionnelles et spécifiques aux applications cryogéniques. Un logiciel spécial a été écrit dans le but essentiel de permettre aux utilisateurs une écriture et une modification faciles de leur programme de contrôle. Le prototype de ce système fonctionne depuis plus d'un an. Le système est maintenant disponible commercialement ; on l'utilise et on prévoit son usage sur plusieurs installations cryogéniques dans lesquelles le laboratoire est impliqué.A modular control system has been developped for the automatization of cryogenic systems. The hardware has been built around a microprocessor ; conventional and spectific modules for cryogenic applications have been developped. A special software has also been written, the first aim of which being an easy writing and modifying ot the process control by the users. The prototype of this system has been operated for more than a year. The system is now commercially available ; it has been used and is under consideration for several cryogenic projects in which the laboratory is involved

A study of bubble chamber operating conditions for holographic image recording

Results of a systematic study of operating conditions for holographic image recording in a heavy liquid rapid cycling bubble chamber are presented. We find that the limiting phenomenon is the turbulences generated by the growth and recompression of the bubbles. To minimize this effect it is necessary to operate the chamber at high temperature where the bubble growth is slow. A total of 40 000 useful holograms were recorded in the NA25 experiment at CERN. Typical running conditions were 10 Hz cycling rate, 80 beam tracks per expansion and a bubble density of 95 bubbles per cm. The bubble diameter was 12 μ. © 1983.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Pleural plaques and asbestosis: Dose- and time-response relationships based on HRCT data

Most studies on asbestos-related diseases are based on chest radiographs, and dose-response relationships are still controversial. The aim of this study was to describe the most relevant parameters of asbestos exposure linked to pleural plaques and asbestosis diagnosed by high-resolution computed tomography (HRCT). A large screening programme including systematic HRCT examinations was organised from 2003 to 2005 in France for formerly asbestos-exposed workers. The time since first exposure (TSFE), level, duration and cumulative exposure to asbestos were used in adjusted unconditional logistic regression to model the relationships of the two diseases. Analysis of a population of 5,545 subjects demonstrated that TSFE (p<0.0001) and cumulative exposure (p=0.02) (or level, depending on the models used), were independently associated with the frequency of pleural plaques. Only cumulative exposure (p<0.0001) or level of exposure (p=0.02) were significantly associated with asbestosis. All trend tests were significant for these parameters. To date and to our knowledge, this study is the largest programme based on HRCT for the screening of asbestos-exposed subjects. Both time-response and dose-response relationships were demonstrated for pleural plaques, while only dose-response relationships were demonstrated for asbestosis. These parameters must be included in the definition of high-risk populations for HRCT-based screening programmes. Copyright©ERS Journals Ltd 2009