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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improved decision support within biocorrosion management for Oil and Gas water injection systems

Stipaničev, Marko 27 August 2013 (has links) (PDF)
The objective of this work, achieved in the framework of the BIOCOR European Network, has been to provide the operators of Sea-Water Injection System (SWIS) with improved decision support. The implication of biological component on carbon steel corrosion was explored as well as the possible synergy with other elements (mechanical stress, material properties…). This work showed that biogenic sulphide production, a corrosion threat for steel, can have different origins in seawater. The production rate can determine kinetics and morphology of corrosion attack, which might be governed by the type of microorganisms present. The key parameters are the availability of electron acceptors and the surrounding environment temperature. Sulfate-Reducing Bacteria (SRB) exhibit more vigorous attack compared to sulfidogenic bacteria or genera Clostridium, both found in the studied SWIS. Microbial activity also affects the mineralization process naturally occurring on carbon steel surface leading to architectures composed of mixed iron (II) and (III) minerals such as iron sulfides, magnetite, iron oxyhydroxides, chukanovite and green rust (sulfated or carbonated) as well as calcareous deposits. Inner layers of these structures could possibly provide an anaerobic habitat for SRBs, where they can flourish by using sulfate from GR(SO42-) as a terminal electron acceptor for their dissimilatory respiration. This enables continuous degradation of steel. Finally, significance of material microstructure and impact of mechanical stress on corrosion processes was also recognized. Grain boundaries and inclusions are playing a role during the initial stage of corrosion attack. This impact can diminish during the immersion time. An elevated bacterial activity coupled with mechanical stress leads to an increase of material deterioration. However, the mechanisms are not different from those usually observed for unstressed steel. Moreover, sulfidogenic microbial activity does not seem to lead to a failure mechanism related to Stress Corrosion Cracking (SCC). In conclusion, the outcomes indicate the possible situations, which may (or may not) lead to breach the safe operating window for a given SWIS.
2

Control Of Slurry Flow, Temperature And Aggressive Diamonds In Chemical Mechanical Planarization

Wu, Changhong January 2015 (has links)
This dissertation presents a series of studies related to the study and control of slurry flow, process temperature, and aggressive diamonds in Chemical Mechanical Planarization (CMP). The purpose of these studies is to better understand the fundamentals of CMP and to explore solutions to some of CMP’s greatest challenges. Within-wafer removal rate non-uniformity (WIWRRNU) is a critical parameter to determine film thickness planarity on a wafer-scale level and it grossly impacts yield. Resolving this issue continues to be an area of intense focus in the industry. The first study in this dissertation shows the feasibility of adopting a new method to improve WIWRRNU during copper CMP that is solely based on intentional local temperature manipulation of the pad. A pad surface thermal management system is developed to locally change pad surface temperature. This system consists of one or more thermal transfer modules contacting the pad surface. In this study, the system is employed to adjust the "center-fast" copper removal rate profile to illustrate its effect during the process. Results shows that, when two thermal transfer modules are employed, local removal rates in the wafer center region decrease significantly while maintaining the removal rates near the wafer edge thereby significantly improving WIWRRNU. Another contribution of this dissertation is the investigation of the effect of pad groove design on slurry injection scheme during interlayer dielectric CMP. A novel slurry injector with multiple slurry outlets is designed, which provides optional slurry injection schemes (i.e. one injection point scheme and multi-injection point scheme). These schemes are compared with the standard slurry application method on a concentrically grooved pad and an xy-groove pad, respectively. On the concentrically grooved pad, the one injection point scheme generates significantly higher oxide removal rates (ranging from 22 to 35 percent) compared to the standard slurry application method at different slurry flow rates. On the xy-groove pad, the one injection point scheme still results in higher removal rates (ranging from 3 to 9 percent), however, its removal rate enhancement is not as high as that of the concentrically grooved pad. In order to further improve slurry availability on the xy-groove pad, the multi-injection point scheme is tested. Results show that the multi-injection point scheme results in significantly higher removal rates (ranging from 17 to 20 percent) compared to the standard slurry application method. This work underscores the importance of optimum slurry injection schemes for accommodating particular groove designs. The last contribution of this dissertation involves a study regarding aggressive diamond characterization and wear analysis during CMP. A 3M A3700 diamond disk is used to condition a Cabot Microelectronics Corporation (CMC) D100 pad for 30 hours. The top 20 aggressive diamonds for two perpendicular disk orientations are identified before the polishing, as well as after 15- and 30-hour polishing. The furrow surface area generated by these top 20 aggressive diamonds and their evolution are analyzed and compared. Results show that the original top 20 aggressive diamonds identified before polishing are subjected to wear after the first 15-hour polishing as the furrow surface area that they generate decreases dramatically (by 47%). As these original aggressive diamonds are worn, seven new aggressive diamonds are "born" and join the new top 20 list for both disk orientations. After the second 15-hour wafer polishing, the furrow surface area of these new top 20 aggressive diamonds do not change significantly. The furrow surface area created by all the active diamonds exhibits the same trend as the top 20 aggressive diamonds, confirming that most pad conditioning work is performed by these aggressive diamonds and that the disk loses its aggressiveness in the first 15 hours of polishing and then maintains its aggressiveness during the second 15 hours, albeit to a lesser extent.
3

Slurry Injection Schemes on the Extent of Slurry Mixing and Availability during Chemical Mechanical Planarization

Bahr, Matthew, Sampurno, Yasa, Han, Ruochen, Philipossian, Ara 29 May 2017 (has links)
In this study, slurry availability and the extent of the slurry mixing (i.e., among fresh slurry, spent slurry, and residual rinse-water) were varied via three different injection schemes. An ultraviolet enhanced fluorescence technique was employed to qualitatively indicate slurry availability and its flow on the pad during polishing. This study investigated standard pad center area slurry application and a slurry injection system (SIS) that covered only the outer half of the wafer track. Results indicated that the radial position of slurry injection and the alteration of fluid mechanics by the SIS played important roles in slurry mixing characteristics and availability atop the pad. Removal rates were found to decrease with slurry availability, while a higher degree of slurry mixing decreased the fraction of fresh slurry and consequently lowered the removal rate. By using a hybrid system (i.e., a combination of slurry injection via SIS and standard pad center slurry application), the polishing process benefited from higher slurry availability and higher fraction of fresh slurry than the conventional pad center slurry application and the shorter SIS, individually. This work underscores the importance of optimum slurry injection geometry and flow for obtaining a more cost-effective and environmentally benign chemical mechanical planarization process.
4

Designing a New SPS Injection System With Numerical Optimisation

Waagaard, Elias January 2022 (has links)
The Super Proton Synchrotron (SPS) injection system plays a fundamental role to preserve the quality of injected high-brightness beams for the LHC physics program and to maintain the maximum storable intensity. The present set-up is the result of years of upgrades and patches of a system that was not conceived for such intensities and beam qualities. In this study, we propose the design of a completely new injection system based on multi-level numerical optimisation of the different constraints, including realistic hardware assumptions. We present the different algorithms and procedures applied in the optimisation process, and we also outline how this generic optimisation framework can be adapted to other situations for optimal accelerator system design.
5

Aplikace vysokotlakého palivového systému na vznětový motor / The High Pressure Fuel System for CI-engine

Strouhal, Pavel January 2016 (has links)
This diploma thesis is focused on examining the development of a diesel tractor engine with a newer injection system, concretely common-rail system. Mainly it is about the application of the high pressure fuel pump, fuel rail and injectors. With regard to the used components are appropriate adjustments made on the engine, and then checked using the available calculations. Brief mention is given to the theoretical summary of the contemporary state of applied injection system and its development trend. Selecting adjustments is primarily based on observed operating load. However, it is also striving to their simplest implementation. An integral part of this work is drawing documentation of newly designed components.
6

Étude expérimentale du rôle de la phase liquide dans les phénomènes d’instabilités thermo-acoustiques agissant au sein de turbomachines diphasiques / Experimental investigation of the spray implication in thermo-acoustic instabilities occurring in liquid-fuelled turbo-engines

Apeloig, Julien 13 September 2013 (has links)
Le travail présenté concerne l'étude des instabilités thermo-acoustiques apparaissant dans une chambre de combustion aéronautique. Le montage expérimental permet de faire varier continument les fréquences de résonances et de passer pour une même condition d'écoulement, d'un régime de combustion stable à un régime instable. La caractérisation complète d'un cas instable comprend une mesure des conditions acoustiques aux limites du banc, une analyse du comportement des phases liquide et évaporée, de celui du dégagement de chaleur instationnaire et une mesure de la fonction de transfert de la flamme. Ces travaux ont mis en évidence trois phénomènes jouant sur l’injection cyclique de carburant liquide. Les temps caractéristiques des différents phénomènes intervenant dans le couplage thermo-acoustique et une distribution spatiale de l'indice de Rayleigh sont présentés. / The purpose of this experimental study was to further our understanding of the fuel spray behavior during combustion instability phenomena in combustion chambers. An aeronautical injection system with dual kerosene lines was mounted on the LOTAR setup, which was equipped with an adjustable exhaust length. Stability maps were generated by varying the global equivalent ratio and the fuel split parameter, for two Inner Exhaust Lengths (IEL). A non-unique multiphase flow condition was found to produce stable and unstable combustion for different IELs. Each configuration was fully characterized. Acoustic boundary conditions were measured using the 2-microphone technique. Different optical techniques were used toanalyze the unsteady behavior of the liquid phase, fuel vapor, and heat release. Moreover, two techniques were exploited to study the Flame Transfer Function using velocity measurement supstream and downstream of the injection device. Altogether, these results highlighted three atomization phenomena occurring during the cycles of thermo-acoustic instabilities. The phase-averaged analysis applied on the different measurements permitted to determine thetime scales associated with each process appearing in the thermo acoustic coupling. This cyclic injection of liquid fuel into the chamber was followed by a vapor phase increase corresponding to a wave of equivalent ratio. The delay between the two phenomena was of10°. In addition, OH* emissions showed a cyclic behavior following these waves. The delay between the wave of equivalent ratio and the unsteady heat release was approximately of 25°.Finally, spatial distribution of the Rayleigh index revealed that the inner recirculation zone contributed to sustain the combustion instability.
7

Improved decision support within biocorrosion management for Oil and Gas water injection systems / Amélioration de l’aide à la décision dans la gestion de la biocorrosion des systèmes d’injection d’eau de l’industrie du gaz et du pétrole

Stipaničev, Marko 27 August 2013 (has links)
L’objectif de ce projet, réalisé dans le cadre du réseau BIOCOR, est de fournir aux opérateurs intervenant dans les systèmes d’injection d’eau, un support amélioré d’aide à la décision. L’implication de composants biologiques dans la corrosion de l’acier au carbone ainsi que les synergies potentielles avec d’autres éléments (contrainte mécanique, propriétés intrinsèques du matériau…) ont été étudiées. Les travaux ont montré que la production du sulfure (une réelle menace pour l’acier) par voie biologique avait différentes origines dans l’eau de mer, les différents taux de production pouvant déterminer diverses cinétiques et morphologies de la corrosion. Les paramètres clé sont la disponibilité des accepteurs d’électrons et la température du milieu environnant. Les bactéries sulfato-réductrices (BSR) sont responsables d’attaques plus sévères que les bactéries sulfidogéniques ou du genre Clostridium, deux groupes identifiés dans le système étudié. L’activité microbienne affecte également les processus de minéralisation qui ont lieu naturellement à la surface de l’acier doux, conduisant à des architectures composées de minéraux à base de fer II et III, comme le sulfure de fer, la magnétite, les oxy-hydroxydes de fer, la chukanovite et la rouille verte (sulfatée ou carbonatée) ainsi que des dépôts calcaires. Les couches internes de ces structures peuvent constituer un habitat favorable, dans lequel les BSR peuvent se développer en utilisant le sulfate de la rouille verte sulfatée comme accepteur terminal d’électrons pour leur respiration dissimilatrice. Ce processus conduit à la dégradation continue de l’acier. Enfin, l’influence de la microstructure du matériau et l’impact du stress mécanique sur la biocorrosion ont été identifiés : les joints de grains et les inclusions jouent un rôle important dans les premières étapes de la corrosion, qui s’estompe avec le temps d’immersion. Un taux élevé de bactéries couplé à une contrainte mécanique conduit à une augmentation de la détérioration sans toutefois révéler des mécanismes nouveaux par rapport à l’absence de contrainte. De plus, l’activité sulfidogénique des bactéries ne semble pas conduire aux mécanismes de rupture par fissuration (Stress Corrosion Cracking). En conclusion, les résultats de ce travail indiquent les situations qui pourraient (ou non) conduire à s’écarter de la ‘fenêtre de sécurité’ pour un système donné. / The objective of this work, achieved in the framework of the BIOCOR European Network, has been to provide the operators of Sea-Water Injection System (SWIS) with improved decision support. The implication of biological component on carbon steel corrosion was explored as well as the possible synergy with other elements (mechanical stress, material properties…). This work showed that biogenic sulphide production, a corrosion threat for steel, can have different origins in seawater. The production rate can determine kinetics and morphology of corrosion attack, which might be governed by the type of microorganisms present. The key parameters are the availability of electron acceptors and the surrounding environment temperature. Sulfate-Reducing Bacteria (SRB) exhibit more vigorous attack compared to sulfidogenic bacteria or genera Clostridium, both found in the studied SWIS. Microbial activity also affects the mineralization process naturally occurring on carbon steel surface leading to architectures composed of mixed iron (II) and (III) minerals such as iron sulfides, magnetite, iron oxyhydroxides, chukanovite and green rust (sulfated or carbonated) as well as calcareous deposits. Inner layers of these structures could possibly provide an anaerobic habitat for SRBs, where they can flourish by using sulfate from GR(SO42-) as a terminal electron acceptor for their dissimilatory respiration. This enables continuous degradation of steel. Finally, significance of material microstructure and impact of mechanical stress on corrosion processes was also recognized. Grain boundaries and inclusions are playing a role during the initial stage of corrosion attack. This impact can diminish during the immersion time. An elevated bacterial activity coupled with mechanical stress leads to an increase of material deterioration. However, the mechanisms are not different from those usually observed for unstressed steel. Moreover, sulfidogenic microbial activity does not seem to lead to a failure mechanism related to Stress Corrosion Cracking (SCC). In conclusion, the outcomes indicate the possible situations, which may (or may not) lead to breach the safe operating window for a given SWIS.
8

Desenvolvimento de método analítico visando a pré-concentração em ponto nuvem em linha para determinação de cádmio em amostras ambientais

Akiba, Naomi January 2016 (has links)
Orientadora: Profa. Dra. Ivanise Gaubeur / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2016. / Os metais cada vez mais poluem o meio ambiente devido as intensas atividades antropogenicas. O cadmio e um metal potencialmente toxico, mesmo em baixas concentracoes, e altamente toxico para os seres humanos, plantas e animais, sendo frequentemente utilizado como indicador de poluicao em aguas. A determinacao do cadmio e geralmente realizada por metodos espectroanaliticos bem estabelecidos. Devido a complexidade das diferentes matrizes ambientais e das baixas concentracoes, algumas amostras necessitam de previa separacao e preconcentracao antes de sua deteccao. A mecanizacao do processo de extracao em ponto nuvem em sistema online permite eventual eliminacao de interferentes, reducao de reagentes utilizados, o aumento da sensibilidade e da precisao, e diminuicao do tempo de analise. Este trabalho propoe a extracao em ponto nuvem em sistema multicomutado de analise em fluxo do complexo formado entre o Cd(II) e (1-(2- piridilazo)-2-naftol) (PAN), utilizando o Triton X-114, com deteccao por espectrometria de absorcao atomica em chama com fonte continua e de alta resolucao (HR-CS FAAS). Foram avaliados alguns parametros relativos a formacao do complexo, a extracao em ponto nuvem e ao sistema multicomutado. Nas melhores condicoes de complexacao e extracao: 4,0 ml da solucao da amostra foram misturados com PAN 311,4 ¿Êmol L-1, Triton X-114 0,6% (m/v) e solucao tampao Tris/Htris+, pH 9.0, , tambem usada para inducao do ponto nuvem, obtendo um volume final de 7,0 mL. A fase rica em tensoativo foi retida em uma minicoluna empacotada com algodao hidrofobico (vazao de 2 mL min-1) e eluida com 300 ¿ÊL de HNO3 0,5 mol L-1 (vazao de 5 ml min- 1). Foi obtida uma curva analitica com faixa linear de 5 . 60 ¿Êg L-1, limite de deteccao de 0,52 ¿Êg L-1, limite de quantificacao 1,7 ¿Êg L-1, coeficiente de variacao de 1,3% (n=12) e fator de enriquecimento igual a 6,6. A frequencia analitica foi de 6 amostras h-1 / Due to intense anthropogenic activities, metal ions are among the most important causer of pollution in the environment. Cadmium even at low concentrations is known to be highly toxic for animals, plants and humans. It is often used as water pollution indicator. Several spectro analytical techniques are available for the trace cadmium. However, due to complexes matrix effects and low concentration there is the necessity of separation and preconcentration procedure before detection. The mechanization of cloud point extraction allows the efficient separation of the analyte. It reduces the amount of sample and reagents, increasing sensitivity, precision, pre-concentration factor and analysis time. This work propose the development of an analytical method by cloud point extraction of Cd(II) and 1-(2 pyridylazo)-2-naphol (PAN) complex using Triton X-114, and detection by means of high-resolution continuum source atomic absorption spectrometry Some parameters related to complex formation, cloud point extraction and multicommuted flow system were evaluated. Under best complexation and extraction conditions: PAN 311.4 mol L-1, Triton X-114 0.6% and Tris/Htris+ buffer solution, pH 9.0, used too cloud point induction, the surfactant rich phase was retained in a hydrophobic cotton packed minicolumn (flow 2 mL min-1) and eluted using 300 ìL HNO3 0.5 mol L-1 solution (flow 5 mL min-1). The analytical curve 5 ¿ 60 ìg L-1 linear range, limit of detection 0.52 ìg L-1-, limit of quantification 1.7 ìg L-1, 1.3% coefficient of variation (n=12) and enhancement factor 6.6 were obtained. The analytical frequency was 6 samples h.1.
9

Développement d’une vanne d’injection de liquide pour l’analyse en ligne par chromatographie en phase gazeuse et ses applications dans le domaine du raffinage : étude du comportement et apport des colonnes monolithiques courtes pour la chromatographie en phase gazeuse haute pression / Development of a liquid injection system dedicated to on-line analysis by gas chromatography and its refining applications : study of the behavior and contribution of short monolithic columns in high pressure gas chromatography

Maniquet, Adrien 14 December 2016 (has links)
En milieu industriel, si l'analyse en ligne d'effluents gazeux à l'aide de la chromatographie en phase gazeuse est actuellement réalisée sans difficultés majeure, l'analyse des liquides reste une des principales problématiques à résoudre. En effet, comparée à une analyse réalisée au laboratoire, l'analyse en ligne d'un échantillon liquide permettrait de s'affranchir de l'étape de prélèvement et de préparation avant injection ainsi que des problèmes de contamination et de représentativité de l'échantillon. Des systèmes d'injection de liquide en ligne sont actuellement disponibles, cependant, des difficultés d'injection liées à la discrimination des analytes sont rencontrées. C'est dans ce contexte qu'une vanne dédiée à l'injection des liquides en ligne a été développée, puis validée en laboratoire, et enfin mise en œuvre sur des applications industrielles pétrolières. Un tout autre enjeu, lié entre autres à la réduction des coûts de maintenance et d'installation, ainsi qu'à la compatibilité de systèmes analytiques destinés à l'industrie et aux micro-pilotes, a orienté des développements instrumentaux vers la miniaturisation des systèmes. Un assemblage de différentes briques technologiques a ensuite été réalisé afin d'évaluer la faisabilité d'un système miniaturisé incorporant la technologie d'injection des liquides en ligne. Finalement et toujours dans ce contexte de miniaturisation, des colonnes monolithiques courtes ont été mises en œuvre en chromatographie en phase gazeuse à haute pression, au laboratoire pour commencer, puis sur des effluents industriels gazeux. Elles ont permis de réaliser des analyses très rapides avec une grande efficacité par unité de longueur tout en pouvant agir sur la sélectivité des colonnes grâce à un contrôle de leurs propriétés de surface / In industry, although on-line analysis of gaseous effluents using gas chromatography is carried out without major difficulty, the analysis of liquids remains problematic and is one of the main issues to be solved. Indeed, compared to an analysis carried out in a laboratory, the on-line analysis of a liquid sample would bypass the steps of sampling and preparation prior to injection and would avoid problems of contamination and representativeness of the sample. Systems for injecting liquids on-line are currently available; however, difficulties are encountered, due to the discrimination of analytes. It is in this context that a valve dedicated to the on-line injection of liquids was developed, validated under laboratory conditions and finally implemented in the oil industry. Another issue, related, amongst other things, to the reduction of maintenance and installation costs, as well as to the compatibility of analytical systems for industry and for micro-pilots, steered instrumental developments towards the miniaturization of systems. Different technological bricks were therefore brought together to assess the feasibility of a miniaturized system involving the technology for on-line injection of liquid. Finally, and still in the context of miniaturization, short monolithic columns were implemented in gaseous phase chromatography at high pressure, first in the laboratory and then on industrial gas effluents. They allowed very fast analyses to be performed which had greater efficiency per unit of length while still being able to act on the selectivity of the columns thanks to the control of their surface properties
10

Systém common rail pro šestiválcový vznětový motor / Common Rail for Six-cylinder CI Engine

Božik, Michal January 2013 (has links)
This thesis deals with the installation of high-pressure common rail injection system for six-cylinder tractor diesel engine. In the first part of the thesis is dismantled issue injection systems and related aspects. The next part is the installation of a fuel injection system, which involves placing components common rail system, the implementation of necessary interventions in engine design and the design of new components. The final section effect control calculations and stress analysis of new injection system components.

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