LNG (Liquefied Natural Gas) is one of the fastest growing energy sources in the U.S. to fulfill the increasing energy demands. In order to meet the LNG demand, many LNG facilities including LNG importation terminals are operating currently. Therefore, it is important to estimate the potential risks in LNG terminals to ensure their safety. One of the best ways to estimate the risk is LOPA (Layer of Protection Analysis) because it can provide quantified risk results with less time and efforts than other methods. For LOPA application, failure data are essential to compute risk frequencies. However, the failure data from the LNG industry are very sparse. Bayesian estimation is identified as one method to compensate for its weaknesses. It can update the generic data with plant specific data. Based on Bayesian estimation, the frequencies of initiating events were obtained using a conjugate gamma prior distribution such as OREDA (Offshore Reliability Data) database and Poisson likelihood distribution. If there is no prior information, Jeffreys noninformative prior may be used. The LNG plant failure database was used as plant specific likelihood information. The PFDs (Probability of Failure on Demand) of IPLs (Independent Protection Layers) were estimated with the conjugate beta prior such as EIReDA (European Industry Reliability Data Bank) database and binomial likelihood distribution. In some cases EIReDA did not provide failure data, so the newly developed Frequency-PFD conversion method was used instead. By the combination of Bayesian estimation and LOPA procedures, the Bayesian-LOPA methodology was developed and was applied to an LNG importation terminal. The found risk values were compared to the tolerable risk criteria to make risk decisions. Finally, the risk values of seven incident scenarios were compared to each other to make a risk ranking. In conclusion, the newly developed Bayesian-LOPA methodology really does work well in an LNG importation terminal and it can be applied in other industries including refineries and petrochemicals. Moreover, it can be used with other frequency analysis methods such as Fault Tree Analysis (FTA).

Ammonia refrigeration systems are widely used in industry. Demand of these systems is expected to increase due to the advantages of ammonia as refrigerant and because ammonia is considered a green refrigerant. Therefore, it is important to evaluate the risks in existing and future ammonia refrigeration systems to ensure their safety. LOPA (Layer of Protection Analysis) is one of the best ways to estimate the risk. It provides quantified risk results with less effort and time than other methods. LOPA analyses one cause-consequence scenario per time. It requires failure data and PFD (Probability of Failure on Demand) of the independent protection layers available to prevent the scenario. Complete application of LOPA requires the estimation of the severity of the consequences and the mitigated frequency of the initiating event for risk calculations. Especially in existing ammonia refrigeration systems, information to develop LOPA is sometimes scarce and uncertain. In these cases, the analysis relies on expert opinion to determine the values of the variables required for risk estimation. Fuzzy Logic has demonstrated to be useful in this situation allowing the construction of expert systems. Based on fuzzy logic, the LOPA method was adapted to represent the knowledge available in standards and good industry practices for ammonia refrigeration. Fuzzy inference systems were developed for severity and risk calculation. Severity fuzzy inference system uses the number of life threatening injuries or deaths, number of injuries and type of medical attention required to calculate the severity risk index. Frequency of the mitigated scenario is calculated using generic data for the initiating event frequency and PFD of the independent protection layers. Finally, the risk fuzzy inference system uses the frequency and severity values obtained to determine the risk of the scenario. The methodology was applied to four scenarios. Risk indexes were calculated and compared with the traditional approach and risk decisions were made. In conclusion, the fuzzy logic LOPA method provides good approximations of the risk for ammonia refrigeration systems. The technique can be useful for risk assessment of existing ammonia refrigeration systems.

Cette thèse a été consacrée à l'étude théorique et expérimentale du couplage contrôlé de la source de photon unique (SPS) aux structures photoniques multidimensionnelles, par l'utilisation de la méthode dite écriture directe par laser (DLW) par absorption ultra-faible à un photon (LOPA). La thèse est constitutée de trois parties principales suivantes:La première partie concerne le caractérisation et l'optimisation des dots quantiques (QD) colloïdaux CdSe/CdS. La dépendance de la longeur d'onde d'excitation a été étudiée. En utilisant une excitation à 532 nm, seul le core est excité et l’effet d'Auger est donc supprimé. Cette approche permet donc d'obtenir avec la suppression de la commutation intermittente et une source de photon unique très stable à température ambiante. Afin d’obtenir une meilleure performance des QDs sur une longue période, nous avons ensuite étudié l'influence du milieu dans lequel les QDs sont logés sur leurs propriétés optiques. En intégrant les QDs dans les matrices de polymère SU-8, nous avons montré que l'environnement polymérique permet non seulement de conserver de bonnes caractéristiques des QDs CdSe/CdS avec une photostabilité élevée, mais également de nous offrir une excellente accessibilité à la fabrication des structures en polymère contenant une particule unique.Dans la deuxième partie, la technique LOPA DLW est utilisée pour le couplage des QDs uniques dans diverses structures photoniques. Deux dispositifs, l’antenne du type ''pilier diélectrique'' sous-lambda et la membrane de réseau circulaire (cavité du type ''bulleye''), ont été étudiés théoriquement et expérimentalement pour améliorer l’émission du QD couplé en termes de l'émission spatiale et de l’émission radiative spontanée de l’émetteur.Dans la troisième partie, la manipulation de la SPS est démontrée en couplant le QD unique à des structures magnéto-photoniques multidimensionnelles. À l'aide d'un champ magnétique externe, le mouvement contrôlable d'un seul QD a été démontré dans un environnement fluidique. En contrôlant l'amplitude et l'orientation du champ magnétique externe, la position et l'orientation de la SPS à base d'un QD ont été manipulées à la demande. Les propriétés optiques, magnétiques et mécaniques des dispositifs magnéto-photoniques hybrides ont été étudiées pour montrer les capacités multifonctionnelles de telles structures. / The thesis has been devoted to study the controlled coupling of a colloidal quantum dot (QD) based single photon source (SPS) into multidimensional polymeric photonic structures by using low-one photon absorption (LOPA) direct laser writing (DLW) technique. The thesis consists of three main parts:The first part addresses the characteristic optimization of the CdSe/CdS based SPS. The excitation wavelength dependence of the QDs was investigated. By using 532 nm, only the core of the QD is excited with the suppression of the Auger effects. Thus, this approach allows for obtaining the suppression of fluorescence intermittency and a stable single-photon emission at ambient conditions. In order to obtain the long-term high fluorescence quality of the QDs, we then studied the influence of the local dielectric medium on the optical properties of the QDs. By incorporating the QDs into a photoresist (SU-8), we demonstrated that the polymeric environment not only enables the long-term preservation of the QD with high photostability but also provides us excellent accessibility to fabricate polymeric structures containing SPS.In the second part, the LOPA-based DLW is employed for the coupling of single QD into various photonic structures. Two devices including submicropillar dielectric antenna and 3D membrane bulleye cavity are theoretically and experimentally investigated to enhance the fluorescence emission of the single QD in terms of far-field angular radiation pattern and the spontaneous radiative emission of the emitter.In the third part, the manipulation of SPS is demonstrated by coupling the single QD into multidimensional magneto-photonic structures. With the aid of an external magnetic field, the controllable movement of the coupled QD was performed in the fluidic environment. The position and orientation of the SPS coupled in the structure were manipulated on demand. The mechanical, magnetic and optical properties of the device are investigated showing the multifunctional capabilities of magneto-photonic structures.

Made available in DSpace on 2014-12-17T14:03:42Z (GMT). No. of bitstreams: 1 AnaKLN_DISSERT.pdf: 1765239 bytes, checksum: 7e63eba3061cff582da8c8d2fd3d9659 (MD5) Previous issue date: 2013-03-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Plukenetia volubilis conhecida popularmente como sacha incha ou amendoa lopo, ? uma planta oleaginosa e trepadeira, pertecente a fam?lia Euphorbiaceae. Suas sementes apresentam alto valor nutritivo e suas folhas s?o utilizadas pela popula??o amaz?nica para tratar doen?as de pele, contudo essa a??o n?o ? comprovada cientificamente. Dentro deste contexto, o presente trabalho prev? uma prospec??o qu?mica e biol?gica de diferentes extratos obtidos das folhas de P. volubilis. : extrato aquoso (EA), metan?lito (EM), etan?lico (EE), clorof?rmico (EC) e hex?nico (EH). A triagem fitoqu?mica foi realizada por meio de rea??es qu?micas de identifica??o e an?lise por cromatografia em camada delgada (CCD), utilizando diferentes eluentes e reveladores. Como parte das an?lises de constitui??o qu?mica dos extratos, foram realizadas dosagens de compostos fen?licos, a??cares totais e prote?nas. Em rela??o ?s atividades biol?gicas, foi avaliada a capacidade antioxidante dos extratos e seus efeitos sob c?lulas tumorais e normais. Com os resultados obtidos foi poss?vel detectar por meio das reacoes a presen?a de compostos fen?licos, flavonoides, saponinas e alcaloides. Por meio da an?lise por CCD foi poss?vel verificar a presen?a de compostos com estruturas de terpenos, polifen?is e flavon?ides. O extrato metan?lico (EM) apresentou uma banda de colora??o verde e Rf 0,65 similar ao padr?o de flavon?ide canferol. Com as metodologias de dosagem qu?mica foi observado uma elevada quantidade de a??cares totais nos extratos de P. volubilis. Os testes para avalia??o da atividade antioxidante revelaram que todos os extratos apresentam capacidade antioxidante. No teste de capacidade antioxidante total (expresso como equivalente em ?cido asc?rbico, EEA/g), os extratos apresentaram valores que variaram entre 59,31 a 97,76 EAA/g. Para o teste de DPPH os valores de sequestro variaram de 88,3% a 62,8%. O teste de viabilidade celular, verificado por meio da redu??o do composto MTT possibilitou observar que os extratos foram capazes de diminuir a viabilidade das c?lulas cancer?genas HeLa e A549, sendo mais eficazes para linhagem HeLa. Os extratos EM e EH (250 ?g/mL) apresentaram redu??o da prolifera??o de HeLa para 54,3 e 48,5%, respectivamente. Enquanto que os extratos EH e EA induziram de forma significativa a prolifera??o de fibroblastos normais 3T3, cerca de 70% a mais que o controle. Resultado semelhante foi observado em macr?fagos Raw, onde foi verificado que a prolifera??o dessas c?lulas tratadas com os extratos EM, EC e EA foi a duas vezes mais que o controle. Nenhum efeito foi observado nas c?lulas CHO quando tratadas com os extratos. Outra abordagem utilizada foi a de citometria de fluxo de modo a avaliar marcadores de morte celular em c?lulas HeLa quando expostas aos extratos de P. volubilis. Os resultados destes ensaio mostraram que os extratos induziram a morte celular via apoptose. Portanto, esses resultados sugerem que os extratos das folhas de P. volubilis s?o potenciais alvos para serem utilizados futuramente no desenvolvimento de f?rmacos com a??o antioxidante, proliferativa e antitumoral

Ce travail porte sur l’étude d’une nouvelle technique de microscopie basée sur le phénomène d’absorption linéaire ultra-faible (LOPA) de matériaux photosensibles pour la fabrication de structures submicrométriques à deux et à trois dimensions (2D, 3D). Premièrement, nous avons étudié théoriquement la distribution de l'intensité lumineuse dans la région focale d’un objectif de microscope de grande ouverture numérique en fonction des différentes conditions de travail, telles que la propagation de la lumière dans un milieu absorbant avec variation d'indice de refraction. Nous avons démontré que lorsque l'on travaille avec un matériau quasi homogène ayant de très faible absorption à la longueur d’onde du faisceau d’excitation, le faisceau laser peut être focalisé en profondeur à l'intérieur du matériau, ce qui permet de manipuler optiquement des objets en 3D. Nous avons ensuite démontré expérimentalement l'utilisation de cette technique pour fabriquer des structures à la demande. Différentes structures 2D et 3D submicrométriques ont été crées en résine SU-8, en utilisant un laser continue de faible puissance à 532 nm. Ces résultats sont similaires à ceux obtenus par la méthode d’absorption à deux photons, mais le coût de fabrication a été énormément réduit. De plus, nous avons démontré qu'il est possible de fabriquer des structures photoniques à base de polymère contenant une seule nanoparticule (NP), en utilisant un procédé à deux étapes. En effet, nous avons d'abord déterminé avec précision la position d'une seule NP d’or, en utilisant une puissance d’excitation très faible, puis nous l'avons insérée dans une structure photonique par une puissance d’excitation plus élevée. Le couplage d'une NP d’or et d'une structure photonique à base de polymère a été ensuite étudié théoriquement et expérimentalement, montrant une amélioration importante de la collection des photons émis par la NP. / This work deals with a novel microscopy technique based on the ultra-low one-photon absorption (LOPA) mechanism of photosensitive materials for fabrication of arbitrary two- and three-dimensional (2D, 3D) submicrometer structures. First, we theoretically investigated the intensity distribution at focusing region of a high numerical aperture objective lens as a function of various working conditions, such as propagation of light mismatched refractive index and/or absorbing media. We demonstrated that when working with refractive index mismatch-free and very low absorption conditions, the light could be focused deeply inside the material, allowing a 3D optical manipulation. We then demonstrated experimentally the use of this simple technique for fabrication of desired structures. Different 2D and 3D structures, with a feature as small as 150 nm, have been created in SU-8 photoresist by using a low power and continuous-wave laser emitting at 532 nm. Furthermore, we demonstrated that it is possible to fabricate a polymer-based photonic structure containing a single nanoparticle (NP), by using a double-step method. Indeed, the LOPA microscopy allowed us first to accurately determine the location of a single gold NP and then to embed it as desired into an arbitrary SU-8 photonic structure. The coupling of a gold NP and a polymer-based photonic structure was theoretically and experimentally investigated showing a six-fold photons collection enhancement as compared to that of a NP in unpatterned film.

Within the safety analysis industry there are a variety of tools used to ensure reliability and security of systems, ranging from mostly qualitative approaches to mostly quantitative. One safety analysis method that lies in between these two is called Layers Of Protection Analysis (LOPA). LOPA is known as a “semi-quantitative” approach that uses a mix of quantitative and qualitative approaches to draw conclusions. In this masters thesis the LOPA approach is demonstrated, in addition to being developed into two alternate LOPA approaches, known as MarkovLOPA and RBDLOPA. These two developed approaches use the concept of Markov chains and Reliability block diagram (RBD) respectively, to extend the applicability of the traditional LOPA methodology. Furthermore, a conventional hydraulic braking system (CHB), which includes ABS/TCS- and ESP functionality was analysed by these three methodologies. The results of the analysis show that in the analysis by LOPA and RBDLOPA 4- and 3 out of 10 scenarios need slight improvements and only 1 scenario for MarkovLOPA. Additionally, the validity of the alternative approaches are analysed by a sensitivity analysis, showing irregularities in the results, leading to the conclusion that further research and development is required prior to industrial applications of the approaches.

Submitted by Marcia Silva (marcia@latec.uff.br) on 2016-07-19T19:28:45Z No. of bitstreams: 1 Dissertacao_MSG_Marcio_Muniz_Final.pdf: 2620890 bytes, checksum: b3ca9261af59621b5f9407cc5ee2bb4c (MD5) / Made available in DSpace on 2016-07-19T19:28:45Z (GMT). No. of bitstreams: 1 Dissertacao_MSG_Marcio_Muniz_Final.pdf: 2620890 bytes, checksum: b3ca9261af59621b5f9407cc5ee2bb4c (MD5) Previous issue date: 2016-03-18 / O objetivo da presente dissertação é desenvolver uma análise crítica da contribuição da metodologia LOPA para a gestão de segurança de processo na indústria e perpetuar sua aplicação. Como modelo metodológico, utilizou-se a pesquisa bibliográfica e a pesquisa exploratória, através de um questionário aplicado. Utilizaram-se os resultados do questionário para avaliar o perfil dos respondentes, testou-se a confiabilidade interna das escalas do questionário através da utilização do alfa de Cronbach e executou-se um modelo de triangulação a luz do referencial teórico, dos resultados do questionário e da experiência e dos conhecimentos teóricos do pesquisador. Como resultados, detectou-se a baixa disponibilidade de estudos guiados pela comunidade científica internacional que efetivamente relacionem a utilização da metodologia LOPA com a gestão de segurança de processos, confirmou-se o baixo nível de difusão do conhecimento e de utilização da metodologia LOPA e detectou-se a alta relevância de inclusão da metodologia em um sistema de gestão de segurança de processos. As confiabilidades internas calculadas para os clusters do questionário obtiveram classificação alta e muito alta. / The main goal of this Dissertation is develop a critical analysis of the LOPA methodology contribution to the Process Safety Management in the Industry and to disseminate the LOPA. The Dissertation methodological model included a Bibliographical Research and an Exploratory Research (Through a survey applied, mainly, to the process safety professionals. The Dissertation tested the internal reliability of the survey scales (Through the Cronbach alfa tool), evaluated the survey participants profile and used a triangulation model considering the theoretical framework, the survey results and the experience and theoretical knowledge of the researcher. The Results detected the low availability of studies guided by international scientific community that effectively connect the methodology LOPA with Process Safety Management, the low level of dissemination of knowledge and the low utilization frequency of methodology LOPA and detected the high significance of LOPA inclusion in a Process Safety Management System. The internal reliability values calculated to the survey clusters obtained high and very high classification.