Characterization and Physical Explanation of Energetic Particles on Planck HFI Instrument

The Planck High Frequency Instrument (HFI) has been surveying the sky continuously from the second Lagrangian point (L2) between August 2009 and January 2012. It operates with 52 high impedance bolometers cooled at 100 mK in a range of frequency between 100 GHz and 1 THz with unprecedented sensitivity, but strong coupling with cosmic radiation. At L2, the particle flux is about 5 \(\hbox {cm}^{-2}\,\hbox {s}^{-1}\) and is dominated by protons incident on the spacecraft. Protons with an energy above 40 MeV can penetrate the focal plane unit box causing two different effects: glitches in the raw data from direct interaction of cosmic rays with detectors (producing a data loss of about 15 % at the end of the mission) and thermal drifts in the bolometer plate at 100 mK adding non-Gaussian noise at frequencies below 0.1 Hz. The HFI consortium has made strong efforts in order to correct for this effect on the time ordered data and final Planck maps. This work intends to give a view of the physical explanation of the glitches observed in the HFI instrument in-flight. To reach this goal, we performed several ground-based experiments using protons and \(\alpha \) particles to test the impact of particles on the HFI spare bolometers with a better control of the environmental conditions with respect to the in-flight data. We have shown that the dominant part of glitches observed in the data comes from the impact of cosmic rays in the silicon die frame supporting the micro-machined bolometric detectors propagating energy mainly by ballistic phonons and by thermal diffusion. The implications of these results for future satellite missions will be discussed.     

Speciation of the gaseous phase of the HI section of the iodine sulphur thermochemical cycle by modeling and inversion of FTIR spectra

This paper presents a laboratory experiment for the study of the liquid–vapor equilibrium of HI–I₂–H₂O ternary mixtures that are involved in the iodine sulphur thermochemical cycle for the production of hydrogen. The apparatus is based on a heated tantalum pressurized vessel equipped with temperature and pressure transducers and carrying windows for optical soundings. It enables recordings of the infrared transmission of the vapor with a Fourier Transform Spectrometer (FTS). The spectra show the signatures of HI and H₂O through rovibrational absorption transitions in both the 4200–5800 cm⁻¹ (1.7–2.4 μm) and 6200–7800 cm⁻¹ (1.3–1.6 μm) regions. In order to analyze the FTS recordings, a spectra calculation software and a dedicated database of spectroscopic parameters have been built. Using these tools, the HI and H₂O amounts in the vapor are determined from least square fits of the experimental spectra in both regions. It is first shown that the measured and the calculated transmissions are in good agreement. Furthermore, the species amounts determined independently in the two spectral regions are very consistent, confirming the quality of the optical soundings.     

Corrosion mechanisms of austenitic stainless steels in nitric media used in reprocessing plants

Austenitic stainless steels type 304L, 316L and 310Nb are largely used as structural materials for equipments handling nitric acid media in reprocessing plants. In almost all nitric media, these materials, protected by a chromium(III) oxide rich layer, remain in their passive state. However, in some particular nitric media, their corrosion potential may be shifted towards their transpassive domain. In this domain, they can suffer intergranular corrosion, even though they are not sensitized owing to their very low carbon content. The corrosion potential of the steel depends greatly on the cathodic reaction involved in the oxido-reduction process between the elements Fe, Cr, Ni of the steel and the oxidizing species of the medium. Three cases of an increase in the corrosion potential can be found in reprocessing media: pure nitric acid-water solutions, in which the cathodic reaction is the reduction reaction of HNO₃; nitric acid media containing oxidizing species, in which the cathodic reaction is the reaction of reduction of the oxidizing species into the reduced one; nitric media containing metallic elements electrochemically more noble than the steels, causing galvanic coupling. In each case, the mechanism and the relevant situations we experimentally studied are described.     

A Sequence-Based Object-Oriented Model for Video Databases

Structuration, annotation and composition are amidst the most crucial modeling issues that video editing and querying in the context of a database entail. In this paper, we propose a sequence-based, object-oriented data model that addresses them in an unified, yet orthogonal way. Thanks to this orthogonality, the interactions between these three aspects are properly captured, i.e., annotations may be attached to any level of video structuration, and all the composition operators preserve the structurations and annotations of the argument videos. We also propose to query both the structuration and the annotations of videos using an extension of ODMG's OQL which integrates a set of algebraic operators on sequences. The overall proposal is formalized and implemented on top of an object-oriented DBMS.     

Experimental study of the vapour–liquid equilibria of HI–I2–H2O ternary mixtures,Part 2: Experimental results at high temperature and pressure

In order to assess the choice of the sulphur–iodine thermochemical cycle for massive hydrogen production, a precise knowledge of the concentrations of the gaseous species (HI, I₂, and H₂O) in thermodynamic equilibrium with the liquid phase of the HI–I₂–H₂O ternary mixture is required, in a wide range of concentrations and for temperatures and pressures up to 300 °C and 50 bar.     

Experimental study of the vapour–liquid equilibria of HI–I2–H2O ternary mixtures,Part 1: Experimental results around the atmospheric pressure

In the framework of the massive production of hydrogen using the sulfur–iodine thermochemical cycle, the design of the reactive distillation column, chosen by CEA for the HIx section, requires the knowledge of the partial pressures of the gaseous species (HI, I₂, H₂O) in thermodynamic equilibrium with the liquid phase of the HI–I₂–H₂O ternary mixture in a wide range of concentrations up to 270 °C and 50 bar. In the first of these two companion papers, we describe the experimental device which enables the measurement of the total pressure and concentrations of the vapour phase (and thus the knowledge of the partial pressures of the different gaseous species) for the HI–I₂–H₂O mixture in the 20–140 °C range and up to 2 bar. This device is used to carry out a large set of experiments investigating various mixtures with optical on-line diagnostics (FTIR for HI and H₂O, UV–visible for I₂). This leads to the determination of the concentrations in the vapour phase for many experimental conditions, results of which are given in this paper. The companion paper (part 2) describes the experimental device which enables measurements of the total pressure and species concentrations in the vapour phase in the process domain.     

Analyse de l’évolution des régions et départements français au travers de leur équipement téléphonique

It is shown that the evolution, during the last ten years, of the téléphonie densities of the french regions and departements, has obeyed a simple linear law, its parameters are explained and discussed. The simple extrapolation of the observed trends diverges from the objectives of development that are the frame of the VII th Plan; the volontarist caracteristic of which is clearly shown.     

TEMPOS: a platform for developing temporal applications on top of object DBMS

We present TEMPOS: a set of models and languages supporting the manipulation of temporal data on top of object DBMS. The proposed models exploit object-oriented technology to meet some important, yet traditionally neglected design criteria related to legacy code migration and representation independence. Two complementary ways for accessing temporal data are offered: a query language and a visual browser. The query language, namely TEMPOQL, is an extension of OQL supporting the manipulation of histories regardless of their representations, through fully composable functional operators. The visual browser offers operators that facilitate several time-related interactive navigation tasks, such as studying a snapshot of a collection of objects at a given instant, or detecting and examining changes within temporal attributes and relationships. TEMPOS models and languages have been formalized both at the syntactical and the semantical level and have been implemented on top of an object DBMS. The suitability of the proposals with regard to applications' requirements has been validated through concrete case studies.     

Non-Hodgkin''s lymphomas and myeloid disorders: deletions associated with t(2;5) and t(3;5) detected by FISH

Tubulovillous adenoma of the duodenum is a rare tumor. Almost all of the lesions have been reported endoscopically and are recognized as small, sessile, polypoid lesions. This article discusses an unusual case of pedunculated tubulovillous adenoma of the duodenum in a 48-yr-old woman. The lesion was discovered on the upper part of the descending duodenum during a gastric mass survey. The polyp was removed using an electrocautery snare and was histologically diagnosed as tubulovillous adenoma.     

Total and partial pressure measurements for the sulphur–iodine thermochemical cycle

First results on the measurement of total and partial pressures over the ternary system HI–_I2–_H2O$\mathrm{HI}–{\mathrm{I}}_2–{\mathrm{H}}_2\mathrm{O}$ are reported. Using original optical online measurements, data on the gas phase speciation are obtained which will help to scale and optimize the reactive distillation column we promote for the HI section of the sulphur–iodine cycle.