En 2014, le réseau de pipelines à travers le monde est estimé à près de 3 500 000 km. Ces conduites en acier traversent plusieurs continents, régions, climats et donc différents types de sols. Elles sont protégées contre la corrosion externe par des revêtements et une protection cathodique. Néanmoins, il subsiste toujours un risque infime de dégradation de l’acier. Afin d’évaluer le risque de rupture d’une conduite, il est nécessaire d’étudier l’influence du sol sur la corrosion de l’acier nu non protégé composant cette conduite. Les paramètres régissant la corrosion des aciers dans les sols étant nombreux, nous nous sommes focalisés sur l’un des paramètres clés, à savoir « la teneur en eau » qui est directement reliée à d’autres paramètres très influents comme : l’aération ou taux d’oxygène, la résistivité du sol et la surface active. Dans cette thèse, nous nous sommes intéressés aux phénomènes se produisant lors de périodes transitoires de séchage/humidification de plusieurs types de sols : argileux, limoneux argileux et sableux. Une électrode multi-coupons a aussi été utilisée afin d’étudier les phénomènes liés à l’hétérogénéité de surface (formation de piles d’aération différentielle). Pour cela, différents coupons en acier provenant d’une conduite d’Air Liquide ont été enfouis pendant de longues périodes (4, 6 et 12 mois) dans différents types de sols. Les vitesses de corrosion sont estimées par électrochimie via la modélisation des courbes de voltammétrie autour du potentiel d’abandon. La surface active de l’électrode est estimée via la mesure de la résistance d’électrolyte par spectroscopie d’impédance électrochimique. Les échantillons sont ensuite analysés par micro-spectroscopie Raman, diffraction des rayons X et microscopie (optique, confocale et électronique à balayage) afin de déduire les mécanismes de corrosion de l’acier. Les résultats montrent, notamment, qu’en cas d’un fort taux d’humidité et d’une faible aération, les vitesses de corrosion sont très faibles (de l’ordre de 20 à 30 µm.an-1) mais atteignent 200 à 400 µm.an-1 lors des phases de séchage. La mesure de courants de couplage effectuée avec l’électrode multi-coupons ainsi que l’analyse de surface des coupons conventionnels ont confirmé la présence de piles d’aération différentielle et le caractère localisé de la corrosion. / In 2014, the pipelines network extended over 3500000 km worldwide. These pipes are passing through various continents, regions, areas and thus different types of soils. They are protected against external corrosion by coatings and cathodic protection. However, there is always a slight risk of carbon steel degradation. In order to evaluate the pipeline failure threat, it is necessary to study the influence of soil corrosion on the uncoated steel which composes this pipe. There are many parameters governing the steel corrosion in soils. We focused on one of the most important parameter “water content”. It is directly linked to other prominent parameters such as oxygen concentration, soil resistance and active area. In this thesis, we addressed the phenomena occurring at transitory periods of drying and remoistening in different types of soils : clayey, silt-loamy and sandy. A multi-coupon electrode was used as well in order to study the phenomena linked to surface heterogeneity (formation of differential aeration cells). For this aim, several steel coupons were buried in different types of soil for long periods (4, 6 and 12 months). The corrosion rates are estimated via electrochemical methods by fitting with a theoretical law the voltammetric curves acquired around the open circuit potential. The active area of the electrode was estimated via the determination of the soil electrolyte resistance by electrochemical impedance spectroscopy. Afterwards, the coupons were analyzed by micro-spectroscopy Raman, X-rays diffraction and microscopy in order to understand the corrosion mechanisms. Results showed that in case of very high moisture content and deaerated conditions, the corrosion rates were very weak (about 20 to 30 µm.yr-1) but reached 200 to 400 µm.yr-1 in the drying periods. The galvanic current measurements performed with the multi-coupon electrode and the surface analysis of the conventional electrodes both confirmed the presence of differential aeration cells and the localized nature of the corrosion.

Large scale production of accessible media above and beyond DAISY Talking Books requires management of the workflow from the initial scan to the output of the media production. DAISY Producer was created to help manage this process. It tracks the transformation of hard copy or electronic content to DTBook XML at any stage of the workflow and interfaces to existing order processing systems. Making use of DAISY Pipeline and Liblouis, DAISY Producer fully automates the generation of on-demand, user-specific DAISY Talking Books, Large Print and Braille. This paper introduces DAISY Producer and shows how creators of accessible media can benefit from this open source tool.

One of the best opportunities to reduce pipeline accidents and subsequent product loss comes from implementing better pipeline condition assessment and fault detection systems. Transient analysis model based condition assessment is the most promising technique because pressure transients propagate entire system interacting with the pipe and any devices in the system. Transient measurements embody a large amount of information about the physical characteristics of the system. The performance of this technique has its difficulties because a highly accurate transient model is required. Real systems have numerous uncertainties and flow system components that presents a major challenge in the development of precise transient analysis models. To improve transient modelling for the performance of condition assessment, this research undertakes a comprehensive investigation into the transient behaviour of distributed and various local energy loss system components in water and gas pipelines. The dynamic behaviours that have been investigated in this research are the effect of unsteady wall resistance, viscoelasticity effects of polymer pipe, and local energy loss elements including leakages, entrapped air pockets, orifices, and blockages during unsteady pipe flow conditions. The dynamic characteristics of these system components are modelled based on the conservative solution scheme using the governing equations in their conservative form. Use of the conservative form of the equations improves the sensitivity and applicability of transient analysis in both liquid and gas pipeline systems. The numerical model results are compared to laboratory experiments in water and gas pipelines to observe the interaction between transient pressure wave and system components and to verify the proposed models. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1337145 / Thesis( Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering 2008

Ce travail se compose de deux parties, dans la première, deux types de méthodologies sont proposées pour garantir l'observabilité sur des systèmes non uniformément observables. Premièrement sont présentées les méthodes basées sur le grammien d'observabilité et, à continuation, les méthodes basées directement sur l'équation de l'observateur. Dans la deuxième partie, diverses techniques sont détaillées pour la détection de défauts (fuites et obstructions) dans les canalisations sous pressions. Pour cela on construit plusieurs modèles en discrétisant les équations du coup de bélier par différences finies, implicites et explicites dans le temps. Sur ces modèles des techniques sont développés en utilisant des observateurs et des algorithmes d'optimisation. Les modèles discrets ainsi que certains observateurs ont été validés par une série d'expériences effectuées dans des canalisations d'essai. Des résultats de convergence, expérimentaux et en simulation sont exposés dans ce mémoire. / This work consists of two parts, in the first one, two types of methods are proposed to ensure the observability of non-uniformly observable systems. Firstly methods based on the observability gramian are presented, and then some methods based directly on the equation of the observer. In the second part, various techniques are detailed for the detection of defaults (leaks and obstructions) in a pipeline under pressure. For that, we built several models by discretizing the water hammer equations using finite differences explicit and implicit in time. Then some techniques are developed using observers and optimization algorithms. Discrete models and some observers were validated by a series of experiments in pipelines. Convergence, experimental and simulation results are presented in this manuscript.

Made available in DSpace on 2014-12-17T14:58:23Z (GMT). No. of bitstreams: 1 JarbasSM_DISSERT.pdf: 2192547 bytes, checksum: 650bc570adcbb8b8a6b8e1427b27389d (MD5) Previous issue date: 2013-08-05 / Ensure the integrity of the pipeline network is an extremely important factor in the oil and gas industry. The engineering of pipelines uses sophisticated robotic inspection tools in-line known as instrumented pigs. Several relevant factors difficult the inspection of pipelines, especially in offshore field which uses pipelines with multi-diameters, radii of curvature accentuated, wall thickness of the pipe above the conventional, multi-phase flow and so on. Within this context, appeared a new instrumented Pig, called Feeler PIG, for detection and sizing of thickness loss in pipelines with internal damage. This tool was developed to overcome several limitations that other conventional instrumented pigs have during the inspection. Several factors influence the measurement errors of the pig affecting the reliability of the results. This work shows different operating conditions and provides a test rig for feeler sensors of an inspection pig under different dynamic loads. The results of measurements of the damage type of shoulder and holes in a cyclic flat surface are evaluated, as well as a mathematical model for the sensor response and their errors from the actual behavior / Garantir a integridade da rede de dutos ? um fator de extrema import?ncia na ind?stria de petr?leo e g?s. A engenharia de dutos utiliza sofisticadas ferramentas robotizadas de inspe??o in-line (durante opera??o) conhecidas como pigs instrumentados. V?rios fatores relevantes dificultam a inspe??o de dutos, especialmente em campos offshore onde se utiliza dutos com multi-di?metros, raios de curvatura acentuados, espessura de parede do duto acima do convencional, escoamento multif?sico e etc. Dentro deste contexto, surgiu um novo Pig instrumentado, chamado de Pig perfilom?trico, para detec??o e dimensionamento de perda de espessura em dutos com danos interno. Esta ferramenta foi desenvolvida para superar diversas limita??es que outros pigs instrumentados convencionais t?m durante a inspe??o. Diversos fatores influenciam nos erros de medi??o do pig afetando a confiabilidade dos resultados obtidos. O presente trabalho aponta diferentes condi??es de opera??o e apresenta uma bancada para ensaiar sensores perfilometricos de pig de inspe??o sob diferentes solicita??es din?micas. Os resultados das medi??es dos danos do tipo ressaltos e rebaixos em uma superf?cie plana c?clica s?o avaliados, assim como, um modelo matem?tico para a resposta do sensor e seus erros em rela??o ao comportamento real

Le Piégeage et le Stockage du dioxyde de Carbone (PSC) est reconnu comme ayant un rôle important dans la lutte contre le changement climatique et la réduction d’émissions de dioxyde de carbone (CO2). Ce processus consiste à capturer le CO2 des sources anthropiques, et le transporter vers des sites de stockage appropriés. Le transport de telles quantités de CO2 entraîne de nouveaux défis pour les concepteurs et les opérateurs des gazoducs. Parmi ces défis, nous citons : le comportement de phase du CO2, la température atteinte lors de la décompression, la présence des différentes impuretés et la pression de service très élevée. Malgré l’enjeu important, et contrairement au gazoduc de transport de gaz naturel et de pétrole, peu d’études ont été consacrées à la sûreté et la rentabilité des gazoducs de transport du CO2. À l’égard de ces défis industriels, cette étude a été menée pour identifier et comprendre les mécanismes de rupture des gazoducs, à haute pression, transportant du CO2 supercritique. Ce travail a engagé la mise au point d’une nouvelle approche qui anticipe l’éclatement du gazoduc. Pour répondre à cette problématique, nous avons utilisé en premier lieu une approche théorique basée sur les fondamentaux de la Mécanique de la Rupture. En second lieu, et en conjonction avec la méthode des éléments finis, nous avons développé un outil numérique robuste. L’ultime objectif de ces travaux de recherche est d’enrichir les codes de dimensionnement des gazoducs, souvent restreints au transport de gaz naturel et au matériau à faible ténacité. De plus, cette thèse apporte une large base de données d’essais de ténacité à basse température liés à des séries d’analyses par éléments finis sous le code de calcul Abaqus 12.6. La finalité de notre recherche réside dans la proposition d’une méthodologie complète d’évaluation des risques d’éclatement des gazoducs en fonction du matériau et de la nature du fluide transporté / Capture, transport, and storage of Carbon dioxide are well-known applications for their key role in the field of climate change and reduction of CO2 emissions. This process involves the use of some particular technologies, not only to collect and concentrate the CO2 emitted by the anthropogenic sources but also to transport it to a suitable storage location. The transport of such a big quantity of CO2 creates new challenges for designers and pipeline operators. For instance, CO2 phase behavior, the temperature reached during the decompression phase, the presence of various impurities as well as the high operating pressure. Contrary to natural gas and oil transportation structures, a very few studies have raised the issue of the integrity of CO2 pipeline. In order to meet the industry needs particularly in this CO2 integrity application, the present research was conducted to identify and to better comprehend pipeline failure mechanisms at high pressures. This work includes the development of a new numerical approach about running ductile fracture arrest for high pressure gas pipeline. To address this issue, we have initially used a theoretical approach based on the fundamental knowledge of Fracture Mechanics. Based on the crack-tip opening angle (CTOA) fracture criterion and the finite element method along with the node release technique, a new two-curve method (TCM) was proposed for the prediction of gas pipelines’ crack arrestability. The results of this newly developed method were discussed and compared to those obtained by using other methods commonly employed in the Fracture mechanics, for instance, Battelle-TCM, HLP and HLP-Sumitomo method

O estudo da diversidade viral em amostras ambientais tem se tornado cada vez mais importante devido a funções-chave desempenhadas por esses organismos. Estudos recentes têm fornecido evidências de que vírus de bactérias (bacteriófagos) podem ser os principais determinantes em ciclos biogeoquímicos de grandes ecossistemas, além de atuarem no fluxo de genes entre comunidades ambientais e na plasticidade funcional das mesmas frente a estresses ambientais. Neste trabalho, propomos a investigação e caracterização da diversidade viral presente em amostras de compostagem através de abordagens não dependentes e dependentes de cultivo. Na primeira abordagem, coletamos amostras seriadas de uma unidade de compostagem do zoológico de São Paulo para realização de sequenciamento metagenômico. O conjunto de sequências gerado foi extensivamente minerado (data-mining) para a produção de resultados de diversidade e abundância de táxons virais ao longo do processo de compostagem. Adicionalmente, procedemos com a montagem e recuperação de sequências virais candidatas a genomas completos e/ou parciais de novos vírus ambientais. Os dois protocolos computacionais utilizados para a mineração de dados encontram-se definidos e automatizados, podendo ser aplicados em quaisquer conjuntos de dados de sequenciamento metagenômico ou metatranscritômico obtidos através da plataforma Illumina. A segunda abordagem correspondeu ao isolamento e caracterização de novos fagos de Pseudomonas obtidos de amostras de compostagem. Três novos fagos foram identificados e tiveram os seus genomas sequenciados. A caracterização genômica desses fagos revelou genomas com alto grau de novidade, insights sobre a evolução de Caudovirales e a presença de genes de tRNA, cuja função pode estar relacionada com um mecanismo dos fagos para contornar o viés traducional apresentado pela bactéria hospedeira. A caracterização experimental dos novos fagos isolados demonstrou grande potencial para lise e dissolução de biofilme da cepa Pseudomonas aeruginosa PA14, conhecida como agente causador de infecções hospitalares em pacientes imunodeprimidos. Em suma, os dados reunidos nesta dissertação caracterizam a diversidade presente no viroma da compostagem e contribuem para o entendimento dos perfis taxonômico, funcional e ecológico do processo. / The study of the viral diversity in environmental samples has become increasingly important due to key-roles that are performed by these organisms in our ecosystems. Recent publications provide evidence that viruses of bacteria (bacteriophages) may be key-players in biogeochemical cycles of large ecosystems, as oceans and forests. Besides, they may also be determinant in the genes flux among populations and in the plasticity of the communities face to environmental stresses. In this work, we propose the investigation and characterization of the viral diversity in composting samples through non-culturable and culturable-dependent approaches. In the first approach, we sampled a composting unit from the Sao Paulo Zoo Park in different time points and proceeded with metagenomic sequencing. The dataset generated was extensively mined to provide results of diversity and abundance of viral taxa through the composting process. Additionally, we proceeded with the assembly and retrieval of candidate sequences to partial or/and complete viral genomes. The two computational protocols were automatized as pipelines and can be applied to any metagenomic dataset of illumina reads. The second approach refers to the isolation and characterization of new Pseudomonas phages obtained from composting samples. Three new phages were identified and their genomes were sequenced. A detailed characterization of these genomes revealed high degree of novelty, insights about evolution of tailed-phages and the presence of tRNA genes, which may be related to a mechanism to bypass host translational bias. The experimental characterization of the new phages demonstrated great potential to lyse bacterial cells and to degrade Pseudomonas aeruginosa PA14 biofilms. In short, the data presented in this dissertation shed light to the composting virome diversity, as well as to the functional and ecological profiles of viruses in the composting environment.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-03-16T12:48:08Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Filipe_Versao_Final_Pos_Defesa_Deposito.pdf: 1855793 bytes, checksum: 366a64a51c618d78933bc62349a182cc (MD5) / Made available in DSpace on 2016-03-16T12:48:08Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Filipe_Versao_Final_Pos_Defesa_Deposito.pdf: 1855793 bytes, checksum: 366a64a51c618d78933bc62349a182cc (MD5) Previous issue date: 2015-08-21 / Hoje as organizações de T.I. estão enfrentando um sério desafio, por um lado temos mercados cada vez mais competitivos, com mudanças quase que rotineiras nos softwares e uma variedade imensa de dispositivos e sistemas operacionais; por outro, os sistemas ficam cada vez mais complexos, integrados a outros serviços e exigindo um alto grau de confiabilidade e disponibilidade dos mesmos, exigindo assim um processo de implantação cada vez mais eficiente e robusto. Nos últimos anos o termo DevOps – colaboração entre desenvolvimento e operação - e suas práticas foram amplamente usados e discutidos sob diferentes aspectos. Assim como no movimento ágil, DevOps também nasceu na indústria e a partir da necessidade da mesma. Por mais que várias organizações já adotem práticas que ficaram conhecidas como DevOps, seu uso ainda não é prescritivo, existindo assim uma variedade de diferentes manifestações de uso em termos de definição e padrão dentre as organizações. Diante disso, esta dissertação teve por objetivo realizar um mapeamento sistemático da literatura e um survey em busca do movimento DevOps, áreas de concentração dos estudos, os principais autores da área e as principais práticas e formas de uso de DevOps nas organizações. Como contribuição, esta pesquisa identificou que dentre as principais áreas de DevOps podem-se destacar (i) entrega, (ii) integração, (iii) e testes contínuos, além da (vi) automação da infraestrutura. Como principais práticas foram possíveis destacar: (a) implantações através de máquinas virtuais, (b) visibilidade do pipeline de implantação, (c) processos robustos de roolbacks, além de técnicas como (d) canary release, (e) toogled features e (f) blue-green deployments. / Today's IT organizations are facing a serious challenge, on the one hand we increasingly competitive markets with routine software’s changes and a wide variety of devices and operating systems; on the other hand, the systems are increasingly complex, integrated with other services and requiring a high degree of reliability and availability requiring a deploy process increasingly efficient and robust. In recent years the DevOps term - a clipped compound of development and operations - and DevOps’s practices were widely used and discussed under different aspects. As agile movement, the DevOps term was also born in the industry’s need. Today many organizations already adopt practices that became known as DevOps its use is not prescriptive, so there is a variety of different manifestations of use in terms of definition and standard among organizations. Therefore, this work aimed to carry out a mapping study and a survey in search of the state of the art DevOps movement, concentration areas of study, the main authors of the area and the main practices and the use of DevOps in organizations. As a contribution, this research found that among the main DevOps area can highlight: (i) continuous delivery; (ii) continuous integration; (iii) continuous testing; and (vi) infrastructure’s automation. Additionally, we can emphasize the main practices in the DevOps adoption: (a) deploys through virtual machines; (b) visibility’s deployment pipeline; (c) robust processes roolbacks, and techniques such as (d) canary release, (e) toogled features and (f) blue-green deployments.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-03-16T14:48:51Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Filipe_Versao_Final_Pos_Defesa_Deposito.pdf: 1855793 bytes, checksum: 366a64a51c618d78933bc62349a182cc (MD5) / Made available in DSpace on 2016-03-16T14:48:52Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Filipe_Versao_Final_Pos_Defesa_Deposito.pdf: 1855793 bytes, checksum: 366a64a51c618d78933bc62349a182cc (MD5) Previous issue date: 2015-08-21 / Hoje as organizações de T.I. estão enfrentando um sério desafio, por um lado temos mercados cada vez mais competitivos, com mudanças quase que rotineiras nos softwares e uma variedade imensa de dispositivos e sistemas operacionais; por outro, os sistemas ficam cada vez mais complexos, integrados a outros serviços e exigindo um alto grau de confiabilidade e disponibilidade dos mesmos, exigindo assim um processo de implantação cada vez mais eficiente e robusto. Nos últimos anos o termo DevOps – colaboração entre desenvolvimento e operação - e suas práticas foram amplamente usados e discutidos sob diferentes aspectos. Assim como no movimento ágil, DevOps também nasceu na indústria e a partir da necessidade da mesma. Por mais que várias organizações já adotem práticas que ficaram conhecidas como DevOps, seu uso ainda não é prescritivo, existindo assim uma variedade de diferentes manifestações de uso em termos de definição e padrão dentre as organizações. Diante disso, esta dissertação teve por objetivo realizar um mapeamento sistemático da literatura e um survey em busca do movimento DevOps, áreas de concentração dos estudos, os principais autores da área e as principais práticas e formas de uso de DevOps nas organizações. Como contribuição, esta pesquisa identificou que dentre as principais áreas de DevOps podem-se destacar (i) entrega, (ii) integração, (iii) e testes contínuos, além da (vi) automação da infraestrutura. Como principais práticas foram possíveis destacar: (a) implantações através de máquinas virtuais, (b) visibilidade do pipeline de implantação, (c) processos robustos de roolbacks, além de técnicas como (d) canary release, (e) toogled features e (f) blue-green deployments. / Today's IT organizations are facing a serious challenge, on the one hand we increasingly competitive markets with routine software’s changes and a wide variety of devices and operating systems; on the other hand, the systems are increasingly complex, integrated with other services and requiring a high degree of reliability and availability requiring a deploy process increasingly efficient and robust. In recent years the DevOps term - a clipped compound of development and operations - and DevOps’s practices were widely used and discussed under different aspects. As agile movement, the DevOps term was also born in the industry’s need. Today many organizations already adopt practices that became known as DevOps its use is not prescriptive, so there is a variety of different manifestations of use in terms of definition and standard among organizations. Therefore, this work aimed to carry out a mapping study and a survey in search of the state of the art DevOps movement, concentration areas of study, the main authors of the area and the main practices and the use of DevOps in organizations. As a contribution, this research found that among the main DevOps area can highlight: (i) continuous delivery; (ii) continuous integration; (iii) continuous testing; and (vi) infrastructure’s automation. Additionally, we can emphasize the main practices in the DevOps adoption: (a) deploys through virtual machines; (b) visibility’s deployment pipeline; (c) robust processes roolbacks, and techniques such as (d) canary release, (e) toogled features and (f) blue-green deployments.

O trabalho tem como objetivo realizar um estudo experimental na bancada do Laboratório Multipropósito de Escoamento Multifásico com o intuito de estudar o fenômeno de intermitência severa em um sistema pipeline-riser com os fluidos água e ar. A intermitência severa pode ocorrer em sistemas pipeline-riser onde o pipeline é descendente seguido de um riser vertical, além de ser necessário a presença de baixas vazões de fluidos. Esse fenômeno é caracterizado por ser cíclico em que há acúmulo de líquido na base do riser e por acabar causando perdas na produção de petróleo e gás devido a grandes flutuações de pressão e vazão que podem durar horas a depender do comprimento do sistema. Os picos de pressão e vazão também podem causar o desligamento do sistema de separação na plataforma. O estudo se dividiu em várias etapas onde inicialmente foram definidos os procedimentos experimentais a serem utilizados. A calibração de placas de orifício foi necessária para o controle de vazão mássica de gás. Os resultados experimentais foram divididos em casos estáveis e instáveis onde a instabilidade é caracterizada pela presença de ciclos de pressão que podem ser observados em históricos de pressão na base do riser. Mapas de estabilidade foram criados e a região instável obtida experimentalmente foi comparada com a curva de estabilidade obtida pelo uso da teoria de estabilidade linear. Os históricos de pressão na base do riser para os casos instáveis obtidos foram comparados com dois modelos numéricos. A variação da pressão no separador foi usada para verificar a mitigação da intermitência severa e/ou da condição instável obtida no sistema para alguns casos instáveis. / The objective of this work is to do an experimental study of the severe slugging phenomenon in the pipeline-riser system of the Multipurpose Multiphase Flow Laboratory by using the fluids air and water. Severe slugging may occur for low flow rates in pipeline-riser systems where a downward pipeline is followed by a vertical riser. In this phenomenon there is liquid accumulation at the bottom of the riser resulting in production losses due to the great fluctuations of pressure and flow rate during its cycles which may last for hours depending on the length of the system. The high pressure values can also cause shutdown of the platform separation system. The first stage of this study was to define the experimental procedure to be adopted. It was necessary to perform a calibration of the orifice plates in order to have a precise control of the gas mass flow rate. The experimental results were divided in stable and unstable cases. The instability is defined by the presence of pressure oscillations at the bottom of the riser. Stability maps were created to compare the stabiliy curve obtained by the stability linear theory with the experimental results. The experimental pressure oscillations were compared with two numerical models. The pressure variation at the separator was studied to verify the mitigation effects during unstable and/or severe slugging conditions.