The plasma environment of an active comet provides a unique setting for plasma physics research. The complex interaction of newly created cometary ions with the flowing plasma of the solar wind gives rise to a plethora of plasma physics phenomena, that can be studied over a large range of activity levels as the distance to the sun, and hence the influx of solar energy, varies. In this thesis, we have used measurements of the spacecraft potential by the Rosetta Langmuir probe instrument (LAP) to study the evolution of activity of comet 67P/Churyumov-Gerasimenko as it approached the sun from 3.6 AU in August 2014 to 2.1 AU in March 2015. The measurements are validated by cross-calibration to a fully independent measurement by an electrostatic analyzer, the Ion Composition Analyzer (ICA), also on board Rosetta. The spacecraft was found to be predominantly negatively charged during the time covered by our investigation, driven so by a rather high electron temperature of ~5 eV resulting from the low collision rate between electrons and the tenuous neutral gas. The spacecraft potential exhibited a clear covariation with the neutral density as measured by the ROSINA Comet Pressure Sensor (COPS) on board Rosetta. As the spacecraft potential depends on plasma density and electron temperature, this shows that the neutral gas and the plasma are closely coupled. The neutral density and negative spacecraft potential were higher in the northern hemisphere, which experienced summer conditions during the investigated period due to the nucleus spin axis being tilted toward the sun. In this hemisphere, we found a clear variation of spacecraft potential with comet longitude, exactly as seen for the neutral gas, with coincident peaks in neutral density and spacecraft potential magnitude roughly every 6 h, when sunlit parts of the neck region of the bi- lobed nucleus were in view of the spacecraft. The plasma density was estimated to have increased during the investigated time period by a factor of 8-12 in the northern hemisphere and possibly as much as a factor of 20-44 in the southern hemisphere, due to the combined effects of seasonal changes and decreasing heliocentric distance. The spacecraft potential measurements obtained by LAP generally exhibited good correlation with the estimates from ICA, confirming the accuracy of both of these instruments for measurements of the spacecraft potential. / <p>QC 20200602</p>

Les Bétons de Poudre Réactive (BPR) sont connus pour leur résistance très élevée et leur bonne durabilité, mais aussi pour leur prix élevé. L’objectif de cette étude concerne la mise au point d’une formulation de BPR extrudable (BPR). Des essais préliminaires d’écoulement au mini cône d’Abrams ont été réalisés avec des teneurs variées en superplastifiant et en substituant partiellement la fumée de silice par du quartz broyé. Cinq mélanges ont été retenus et caractérisés de façon systématique au microscope électronique à balayage et en diffraction des Rayons X. Une étude complète de retrait au jeune âge, de résistance mécanique et de durabilité face à l’azote et aux ions chlorure a été menée. Un montage expérimental d’extrusion a été mis au point. Un mélange incorporant du quartz broyé en remplacement d’une fraction de la fumée de silice et une composition optimisée en superplastifiant montre des propriétés intéressantes : extrudabilité, très bonne durabilité, performances mécaniques améliorées et retrait diminué. Sur cette composition, l’étude microstructurale met en évidence le rôle que joue le superplastifiant sur la chimie d’hydratation avec une forte consommation en bélite. Ce mélange permet ainsi de diminuer le coût de fabrication pour un BPR en permettant d’économiser la fumée de silice coûteuse et en ne nécessitant aucun traitement thermique. / Reactive Powder Concrete (RPC) is well known for ultra-high mechanical performances and very good durability as well as for a high cost. The aim of this study is to find an extrudable RPC. Abrams cone preliminary tests were made with various contents of superplasticizer and a partial substitution of silica fume by crushed quartz. Then, fives concrete samples were chosen and systematically characterized by scanning electron microscopy and X-ray diffraction. Then, a complete study was made including early-age shrinkage, mechanical strength, gas permeability and chloride diffusion measurements. An experimental extruder was build. Among the five compositions, one of them, where crushed quartz replaces a part of silica fume, exhibits very good properties: good extrudability, very good durability, and better mechanical strength with an improvement of shrinkage. The microstructural study of this composition highlights the effect of the superplasticizer on hydration, with high belite consumption. This composition allows a lower cost of RPC with a decreasing of silica fume content, without thermal treatment.

<p>Building Information Modeling -BIM- is an innovative method to seamlessly bridgecommunication within the architecture, engineering and construction industries.With BIM software you can exchange information during the design, construction,and maintaining. BIM can be seen as a continuation of the CAD software, wherethe users exchanged information by word of mouth, now is made automatically.To get the effect required for BIM one or more CAD-systems have to work togetherto exchange information. Revit Architecture is an application by Autodeskwhere BIM is used from the design and construction to the documentation andmaintaining of a building. Configura is one of the major software developers of interiorsolutions and want to integrate their software with Revit Architecture. Theconcept of objects in both software system suit well to be used in BIM and witha live connection these could be shared between the applications. One of the conclusionsin this investigation was that the only way to have integration betweenthe applications was to use the API provided by Autodesk. And therefore theimplementation is limited to the function in it. Revit API is a powerful programmingenvironment that let 3rd party software extend the functionality in Revit.The results show how Remote Procedure Call as a communication tool can beused to exchange data between the applications, how different type of data can berepresented in both applications, and why we cannot have a live synchronization.</p>

Scientific projects, businesses, and individual devices such as smart phones, tablets and embedded devices are collecting and retaining unparalleled and growing amounts of data. Initially, spatial locality of the data (collocation of data and application) cannot be assumed and local resource constraints impact monolithic legacy applications. Resource restrictions and less feasible approaches such as moving large data sets within these paradigms are not feasible for certain legacy applications. As such we have taken a renewed look at Remote Procedure Call mechanisms and designed, built and evaluated a RPC mechanism called Automated Legacy system Remote Procedure Call generator (ALRPC). ALRPC allows us to convert monolithic applications into distributed systems by selectively and semi-automatically moving individual functions to different process spaces. This improves spatial locality and resource constraints of critical functions in legacy applications. Empirical results from our initial experiments show that our mechanism’s level of automation outperforms existing industry strength tools and its performance is competitive within the scope of this work. / Graduate / 0984

Chemnitz, Techn. Univ., Diplomarb., 2001.

Building Information Modeling -BIM- is an innovative method to seamlessly bridgecommunication within the architecture, engineering and construction industries.With BIM software you can exchange information during the design, construction,and maintaining. BIM can be seen as a continuation of the CAD software, wherethe users exchanged information by word of mouth, now is made automatically.To get the effect required for BIM one or more CAD-systems have to work togetherto exchange information. Revit Architecture is an application by Autodeskwhere BIM is used from the design and construction to the documentation andmaintaining of a building. Configura is one of the major software developers of interiorsolutions and want to integrate their software with Revit Architecture. Theconcept of objects in both software system suit well to be used in BIM and witha live connection these could be shared between the applications. One of the conclusionsin this investigation was that the only way to have integration betweenthe applications was to use the API provided by Autodesk. And therefore theimplementation is limited to the function in it. Revit API is a powerful programmingenvironment that let 3rd party software extend the functionality in Revit.The results show how Remote Procedure Call as a communication tool can beused to exchange data between the applications, how different type of data can berepresented in both applications, and why we cannot have a live synchronization.

Le passage à l'échelle des applications multi-fil sur les systèmes multi-cœuractuels est limité par la performance des algorithmes de verrou, à cause descoûts d'accès à la mémoire sous forte congestion et des défauts de cache. Lacontribution principale présentée dans cette thèse est un nouvel algorithme,Remote Core Locking (RCL), qui a pour objectif d'améliorer la vitessed'exécution des sections critiques des applications patrimoniales sur lesarchitectures multi-cœur. L'idée de RCL est de remplacer les acquisitions deverrou par des appels de fonction distants (RPC) optimisés vers un fild'exécution matériel dédié appelé serveur. RCL réduit l'effondrement desperformances observé avec d'autres algorithmes de verrou lorsque de nombreuxfils d'exécution essaient d'obtenir un verrou de façon concurrente, et supprimele besoin de transférer les données partagées protégées par le verrou vers lefil d'exécution matériel qui l'acquiert car ces données peuvent souventdemeurer dans les caches du serveur.D'autres contributions sont présentées dans cette thèse, notamment un profilerpermettant d'identifier les verrous qui sont des goulots d'étranglement dansles applications multi-fil et qui peuvent par conséquent être remplacés par RCLafin d'améliorer les performances, ainsi qu'un outil de réécriture de codedéveloppé avec l'aide de Julia Lawall. Cet outil transforme les acquisitions deverrou POSIX en acquisitions RCL. L'évaluation de RCL a porté sur dix-huitapplications: les neuf applications des benchmarks SPLASH-2, les septapplications des benchmarks Phoenix 2, Memcached, ainsi que Berkeley DB avec unclient TPC-C. Huit de ces applications sont incapables de passer à l'échelle àcause de leurs verrous et leur performance est améliorée par RCL sur unemachine x86 avec quatre processeurs AMD Opteron et 48 fils d'exécutionmatériels. Utiliser RCL permet de multiplier les performances par 2.5 parrapport aux verrous POSIX sur Memcached, et par 11.6 fois sur Berkeley DB avecle client TPC-C. Sur une machine SPARC avec deux processeurs Sun Ultrasparc T2+et 128 fils d'exécution matériels, les performances de trois applications sontaméliorées par RCL: les performances sont multipliées par 1.3 par rapport auxverrous POSIX sur Memcached et par 7.9 fois sur Berkeley DB avec le clientTPC-C. / The scalability of multithreaded applications on current multicore systems is hampered by the performance of lock algorithms, due to the costs of access contention and cache misses. The main contribution presented in this thesis is a new lock algorithm, Remote Core Locking (RCL), that aims to improve the performance of critical sections in legacy applications on multicore architectures. The idea of RCL is to replace lock acquisitions by optimized remote procedure calls to a dedicated hardware thread, which is referred to as the server. RCL limits the performance collapse observed with other lock algorithms when many threads try to acquire a lock concurrently and removes the need to transfer lock-protected shared data to the hardware thread acquiring the lock because such data can typically remain in the server's cache. Other contributions presented in this thesis include a profiler that identifies the locks that are the bottlenecks in multithreaded applications and that can thus benefit from RCL, and a reengineering tool developed with Julia Lawall that transforms POSIX locks into RCL locks. Eighteen applications were used to evaluate RCL: the nine applications of the SPLASH-2 benchmark suite, the seven applications of the Phoenix 2 benchmark suite, Memcached, and Berkeley DB with a TPC-C client. Eight of these applications are unable to scale because of locks and benefit from RCL on an x86 machine with four AMD Opteron processors and 48 hardware threads. Using RCL locks, performance is improved by up to 2.5 times with respect to POSIX locks on Memcached, and up to 11.6 times with respect to Berkeley DB with the TPC-C client. On an SPARC machine with two Sun Ultrasparc T2+ processors and 128 hardware threads, three applications benefit from RCL. In particular, performance is improved by up to 1.3 times with respect to POSIX locks on Memcached, and up to 7.9 times with respect to Berkeley DB with the TPC-C client.

La théorie de la QCD (Quantum ChromoDynamics) prédit l’existence d’une nouvelle phase de la matière nucléaire à très haute température. Cette phase, caractérisée par un déconfinement des quarks au sein des hadrons, est appelée QGP (Quark Gluon Plasma). Le spectromètre à muons de l’expérience ALICE (A Large Ion Collider Experiment) a pour but d’étudier les propriétés du QGP aux densités d’énergie extrêmes atteintes dans les collisions d’ions lourds au LHC (Large Hadron Collider). Le système de déclenchement du spectromètre à muons, appelé MUON TRG est, pour une large part, sous la responsabilité du groupe ALICE de Clermont-Ferrand. Il se compose de quatre plans de détecteurs RPC (Resistive Plate Chamber) d’une superficie totale de 140 m2, de 21k voies de lecture et d’une électronique de décision rapide. Il a été conçu afin de reconstruire ”en ligne” des traces (muons), dans un environnement présentant un important bruit de fond. Une décision de trigger, pour les ”single muons” et les ”dimuons”, est délivrée toutes les 25 ns (40 MHz) avec un temps de latence relatif à l’interaction proche de 800 ns. Les performances, en particulier celles liées à la décision de trigger, obtenues avec des outils de test dédiés, les évènements cosmiques, les premiers faisceaux d’injection dans le LHC ainsi que les premières collisions proton-proton à √s = 900 GeV seront présentés. / The QCD theory (Quantum ChromoDynamics) predicts the presence of a new phase of the nuclear matter at very high temperature. This phase, characterized by a deconfinement of quarks within hadrons, is called QGP (Quark Gluon Plasma). The muon spectrometer of the ALICE experiment (A Large Ion Collider Experiment) aims at investigating the propertiesof the QGP at the extreme energy density reached in heavy ion collisions at LHC (Large Hadron Collider). The trigger system of the Muon Spectrometer, called MUON TRG mainly come under the responsability of the Clermont-Ferrand ALICE team. It consists of four planes of RPC (Resistive Plate Chamber) detectors with a total area of 140 m2 , 21k front-end channels and fast-decision electronics. It is designed to reconstruct (muon) tracks online, in a large background environment. A fast trigger decision, for both single-muons and dimuons, is delivered each 25 ns (40 MHz) with a latency with respect to the interaction of about 800 ns. The performances, especially the ones related to trigger decision, obtained with dedicated test tools, cosmic rays, first LHC injection beams and first proton-proton collisions at √s = 900 GeV will be presented.

The focus of this thesis is the development of Resistive Plate Chambers (RPCs) with ceramic electrodes. The use of ceramic composites, Si3N4/SiC, opens the way for the application of RPCs in harsh radiation environments. Future Experiments like the Compressed Baryonic Matter (CBM) at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt will need new RPCs with high rate capabilities and high radiation tolerance. Ceramic composites are specially suited for this purpose due to their resistance to radiation and chemical contamination. The bulk resistivity of these ceramics is in the range 10^7 - 10^13 Ohm cm. The bulk resistivity of the electrodes is the main factor determining the rate capabilities of a RPC, therefore a specifific measuring station and a measurement protocol has been set for these measurements. The dependence of the bulk resistivity on the difffferent steps of the manufacturing process has been studied. Other electrical parameters like the relaxation time, the relative permittivity and the tangent loss have also been investigated. Simulation codes for the investigation of RPC functionality was developed using the gas detectors simulation framework GARFIELD++. The parameters of the two mixtures used in RPC operation have been extracted. Furthermore, theoretical predictions on time resolution and effi ciency have been calculated and compared with experimental results. Two ceramic materials have been used to assemble RPCs. Si3N4/SiC and Al2O3 with a thin (nm thick) chromium layer deposited over it. Several prototypes have been assembled with active areas of 5x 5 cm^2, 10x 10 cm^2 and 20 x20 cm^2. The number of gaps ranges from two to six. The gas gap widths were 250 micro meter and 300 micrometer. As separator material mylar foils, fifishing line and high-resistive ceramics have been used. Different detector architectures have been built and their effffect on RPC performance analysed. The RPCs developed at HZDR and ITEP (Moscow) were systematically tested in electron and proton beams and with cosmic radiation over the course of three years. The performance of the RPCs was extracted from the measured data. The main parameters like time resolution, effi ciency, rate capabilities, cluster size, detector currents and avalanche charge were obtained and compared with other RPC systems in the world. A comparison with phenomenological models was performed.

La mise à niveau du détecteur CMS (Upgrade Phase-2) en 2024 prévoit l'installation de nouveaux détecteurs à plaques résistives (RPC) dans les 2 secteurs les plus externes et les plus vers l’avant (RE3/1 et RE4/1) des bouchons. Des RPC en verre de basse résistivité (GRPC) ont été proposées afin d'instrumenter ces secteurs où le flux de particules sera de l’ordre du kHz/cm², valeurs pour lesquelles les RPC actuelles de CMS ne sont pas efficaces. Cette thèse porte sur l'étude et la caractérisation de ces GRPC, de leur électronique de lecture associée et de leur résistance aux irradiations. Deux méthodes de production de chambres de taille moitié des chambres finales à partir de pavages de verres de taille maximale 32*30cm² ont été élaborées et testées. Un nouveau circuit électronique (PCB) à bandes de détection non segmentées en êta et lues par des puces dédiées (PETIROC2A) est également présenté. Il permet grâce à des chronomètres numériques (TDC) de 25 picosecondes de résolution, une précision de l'ordre du centimètre sur la mesure de la position du passage des particules le long des bandes. Cette thèse décrit ces nouveaux dispositifs et présente les résultats obtenus avec ceux-ci lors de tests en faisceaux auprès des accélérateurs PS et SPS du CERN ainsi qu'au Gamma Irradiation Facility (GIF++). Cette étude montre que le verre de basse résistivité, bien que supportant les flux de particules, n'est pas la meilleure solution pour l'environnement de CMS car il nécessite un mélange gazeux différent pour fonctionner. Cependant, la nouvelle électronique a prouvé son adéquation à cet environnement et est maintenant considérée comme l'option privilégiée pour la mise à niveau de CMS / The installation of new resistive plate chamber detectors (RPCs) in the 2 most remote sectors (RE3 / 1 and RE4 / 1) of the CMS End-Caps is planned during the Phase-2 CMS upgrade in 2024. Glass Resistive Plate Chambers (GRPC) with low resistivity glass as electrodes have been proposed to equip these sectors. These detectors should sustain these zones' particle rate. The aim of this Thesis is to study and characterise these detectors, their associated readout electronics and their behaviour under radiations.Two ways of building half size chambers by tesselation of glass plates with maximal size 32*30cm² have been developped. A new PCB with strips readout read by dedicated ASICs (PETIROC2A) without eta segmentation is also described. It allows, thanks to a 25 ns time-resolution TDC to estimate the particle crossing position on the strip with a resolution of the order of cm. This manuscript describes all these devices and discusses the devices' performance measured in beam tests done at the CERN PS and SPS accelerator and at the Gamma Irradiation Facility (GIF++). This study shows that the low resistivity glass, though able to sustain the particule rate, is not the best option for the CMS upgrade. On the contrary, the tested electronic has been proven to fit the CMS upgrade requirements and is now considered as the baseline of the CMS End-Caps RPC upgrade project