Dissertations / Theses on the topic 'FCCU'
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Veluswamy, Ganesh Kumar. "Hydrodynamics of industrial scale FCCU stripper." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1965.
Full textWhitcombe, Joshua Matthew, and n/a. "Study of Catalyst Particle Emissions From a Fluidized Catalytic Cracker Unit." Griffith University. School of Environmental Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20031003.152200.
Full textWhitcombe, Joshua Matthew. "Study of Catalyst Particle Emissions From a Fluidized Catalytic Cracker Unit." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/367301.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental Engineering
Faculty of Environmental Sciences
Full Text
Sarginson, James Stanley. "Vanadium interaction with FCC catalysts." Thesis, Open University, 1997. http://oro.open.ac.uk/57712/.
Full textLin, Chuang-Chia 1968. "Cyclic deformation of FCC crystals." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37757.
Full textGodard, Desmarest Sophie. "The processing, microstructure and creep properties of Pb-free solders for harsh environments." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c9f90f13-fcc3-4bb4-8a2c-b980aacb89c9.
Full textChang, Zhongwen. "Modelling of Dislocation Bias in FCC Materials." Licentiate thesis, KTH, Reaktorfysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122407.
Full textQC 20130530
Kortunov, Pavel, Sergey Vasenkov, Jörg Kärger, Elía M. Fé, M. Perez, Michael Stöcker, George K. Papadopoulos, et al. "Investigations of molecular diffusion in FCC catalysts." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196587.
Full textKortunov, Pavel, Sergey Vasenkov, Jörg Kärger, Elía M. Fé, M. Perez, Michael Stöcker, George K. Papadopoulos, et al. "Investigations of molecular diffusion in FCC catalysts." Diffusion fundamentals 2 (2005) 97, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14435.
Full textSengupta, Rohini. "Long-Lived Particles at the FCC-ee." Thesis, Uppsala universitet, Tillämpad kärnfysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-444329.
Full textMallory, Donald Paul. "Co-diffusion of particles in biological systems studied using PIE-FCCS." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1627666937482877.
Full textLustig, Steven K. "Microstructural analysis of finite deformation in FCC polycrystals." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/15916.
Full textRong, Yu. "FCC regeneration process design for co2 emissions reduction." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505485.
Full textChalapati, Sachin. "Toluene Mediated FCC of LDPE Using Ionic liquids." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17973.
Full textProgram: Master of Science with a Major in Resource recovery – Industrial biotechnology
Vieira, William Gonçalves. "FCC : controle preditivo e identificação via redes neurais." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267590.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A unidade de Craqueamento Catalítico em Leito Fluido - FCC, modelo Kellogg Orthoflow F., representa um processo de refino de petróleo apresentando característica altamente não linear, possuindo fortes interaçães entre as variáveis de produção, e condições de operação extremamente severas. Essas unidades são constituídas basicamente de duas seções: uma de reação catalítica na qual ocorrem as reações de quebra de cadeia hidrocarbônica e também há formação de coque, desativando o catalisador; e outra seção onde ocorre a regeneração do catalisador desativado. O objetivo dessa unidade é transformar produtos de elevado peso molecu1ar, que apresentam baixo valor agregado, em compostos de elevado valor comercial. As unidades FCC, devido às condições severas de operação, necessitam de um controle rigoroso de determinadas variáveis operacionais. Apesar de existirem instalados controladores avançados baseados em modelos de convolução, fteqüentemente essas unidades são reguladas por meio de controladores PID padrões e também através de controle manual baseado no conhecimento de operadores das refinarias. O presente estudo tem como objetivo desenvolver um controlador preditivo multivariável (Multivariable Predictive Control - MPC) para ser implementado na unidade FCC, utilizando Redes Neurais Artificiais (RNA) como modelo interno do controlador. Inicialmente é previsto realizar a identificação do processo da FCC em RNA, obedecendo a seguinte estratégia: usando um modelo fenomenológico que representa a unidade industrial, e partindo de um estado inicial são aplicados diversos degraus nas variáveis manipuladas analisando as respostas nas variáveis controladas do processo. A partir destas simulações são gerados diversos conjuntos de dados divididos em grupos de treinamento, validação e teste. Diversas redes neurais do tipo multicamada feedforward são então criadas para representar o modelo fenomenológico, sendo selecionada aquela que apresenta melhor desempenho, quando comparada com o modelo. A configuração da RNA escolhida como modelo interno foi 8x15x4 (camadas de entrada, escondida e de saída, respectivamente) apresentando um erro relativo máximo de 1% quando comparado com os resultados do modelo rigoroso. Posteriormente, foi previsto desenvolver um controlador preditivo multivariável usando como modelo interno esta rede selecionada. Este controlador foi implementado dentro da rotina do modelo fenomenológico, sendo então realizados testes para verificar seu desempenho, comparando o resultado com o sistema aberto e também com o controlador DMC (Dynamic Matrix Contro!) existente. Diversos horizontes de predição e controle foram analisados, sendo selecionados aqueles que apresentaram melhor desempenho. Foi introduzido um ruído nos sinais do modelo fenomenológico para testar a robustez do controlador proposto. O controlador apresentou bom desempenho mesmo na presença de ruídos de 1,5%, levando sempre as variáveis controladas para seus valores de referência, o que comprova sua robustez. Baseados nestes resultados, conclui-se que um controlador preditivo multivariável baseado em RNA é perfeitamente capaz de controlar um sistema não linear de porte do FCC, onde elevada interação entre suas variáveis operacionais e fortes restrições estão presentes. Isto nos permite extrapolar que são boas as expectativas para uma futura utilização na unidade industrial, principalmente devido à sua simplicidade, robustez e facilidade de implementação, a despeito da dificuldade de sintonia do controlador
Abstract: The Fluid Cracking Catalytic unit - FCC, Kellogg Orthotlow F. model, represents a very strong nonlinear process, with severe interactions among the process variables, and extremely severe operation conditions. The unit is composed of two sections: one is the catalytic reaction, where the hydrocarbon breaks chain reactions and coke deposition take place becoming the catalyst inactive, and the other where the catalyst regeneration happens. The objective is to transform products derived ITom petroleum, with high molecular weight and low added value, into products with higher profit. Due to the severe operation conditions, rigorous control of some variable is needed. In spite of the existence of advanced control based on a convolution model, in practice, FCC units are ftequently regulated by standard PID controllers, and also through manual control actions based on the knowledge of the refinery operators. The objective of this study is to develop a Multivariable Predictive Control (MPC) to be implemented in the FCC unit, using the Artificial Neural Networks (ANN) as internal model. Initially, the process identification in ANN of the FCC was done by the following strategy: an initial state was fust achieved using numerical simulations based on the phenomenological mo deI. Then, several steps changes were applied to the manipulated variables and the response in the controlled variables were monitored and recorded. From these simulations, several groups of data were generated for training, validation and testing. The Neural Network of multilayer feedforward type were created to represent the phenomenological model, being selected the one that better represents the phenomenological model. The ANN configuration chosen to be the internal model was 8x15x4 (Input x Hidden x Output) architecture, with a maximum relative error below 1 % when comparing the results with the phenomenological model results. Later on, it was developed a multivariable predictive control based on this internal model. This control was implemented inside the routine of the phenomenological model. The performance tests were evaluated comparing the results with the open system and with the Dynamics Matrix Control (DMC). Several prediction and control horizons were analyzed. The ANN control presented good performance even in the presence of noise of 1,5% of intensity, taking back the controlled variables to its setpoints, proving its robustness. Based on these results, a multivariable predictive control based on ANN showed be perfectly able to control a nonlinear system like a FCC unit, where high interactions among process variables, and strong restriction conditions exists. This allows us to have good expectations for a future use in the industrial unit, mainly due to its simplicity, robustness and facility ofuse, in spite ofthe difliculty oftune control
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
Swisher, Douglas Lee. "Deformation banding and grain refinement in FCC materials." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FSwisher.pdf.
Full textRoss, Seamus. "Dress pins from Anglo-Saxon England : their production and typo-chronological development." Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:3976b772-fccd-41fe-b8c7-f4ae08ac0295.
Full textKelly, Luke. "A stochastic Dollo model for lateral transfer." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:6884785c-fccc-4044-b5b2-7a8b7015b2a5.
Full textRaeside, Alexander. "The effect of low temperature on alternative splicing in barley." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/f29963da-fcc3-4b73-82aa-d882b8382923.
Full textHuang, Leilei. "Fabrication and characterisation of ultrafast direct laser written waveguides." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:7e40e1ee-fcc3-4797-953d-8be5c7af1334.
Full textJones, Christina Jane. "The utility of social cognition models in explaining adherence to self-care behaviours amongst adolescents and young adults with food allergy." Thesis, University of Brighton, 2012. https://research.brighton.ac.uk/en/studentTheses/970af16a-fcc4-4175-8827-e00a24e4bfb9.
Full textSchreiner, Jennifer Ann. "Women working for their freedom : FCWU and AFCWU and the women question." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/15841.
Full textThis thesis has two parallel processes of investigation. Firstly, it is an investigation of the extent to which a trade union can successfully participate in the struggle for working women's rights at work and concerning motherhood and childcare, and in the struggle for the realisation of the political aspirations of women workers within a capitalist society. Secondly, the thesis examines the ideological position of the Food and Canning Workers Union in order to refine the theoretical understanding of the woman question in South Africa. Research methods have relied on use of archival documents, both published and unpublished; oral history; secondary sources on the union being studied and on South African society; as well as classical and contemporary texts on the theory of women's oppression and its interconnection with exploitation. The research has been hindered by the historical repression meted out by the South African state, which has forced people into exile, banned written sources, and removed archival material from South Africa. The recent repression has severely hampered the extent of interviewing and discussion, as well as made the process of research and writing of the thesis a difficult undertaking. The union's organising strategy is examined in terms of the following three issues: 1. Because of their dual responsibilities as worker and mother, and because of their relatively unorganised position, women workers are ultra-exploited. What role can a union play in fighting against the various aspects of this? The specific aspects of ultra-exploitation found in the food and canning industry are temporary employment and periodic unemployment; child labour; piece-work; excessive overtime. 2. The inclusion of women into wage labour faces them with a task of combining motherhood and wage labour. How can a union win demands to assist these women workers with this task? The two ways in which the union confronted this question were maternity rights and childcare facilities. 3. The assault on working class in terms of the right to work, the right to live where one chooses, the right to family life, and the right to a decent standard of living was a burden to working class women in particular.
Sinclair, Chad. "Co-deformation of a two-phase FCC/BCC material /." *McMaster only, 2001.
Find full textSpearot, Douglas Edward. "Atomistic Calculations of Nanoscale Interface Behavior in FCC Metals." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7230.
Full textLeonel, Raquel Folmann. "Estudo dos mecanismos de reativação de catalisadores FCC eletrorremediados." reponame:Repositório Institucional da UFPR, 2016. http://hdl.handle.net/1884/45441.
Full textCoorientador: Profª. Drª. Maria José J. de Santana Ponte
Tese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia e Ciência dos Materiais - PIPE. Defesa: Curitiba, 26/07/2016
Inclui referências : f. 87-93
Área de concentração: Engenharia e ciência de materiais
Resumo: A crescente geração de catalisador desativado nas unidades de Craqueamento Catalitico Fluidizado e sua elevada importância como insumo nas refinarias brasileiras motiva estudos para seu reaproveitamento. Apos o uso e desativação dos catalisadores, estes sao destinados a aterros Classe I, devido a sua periculosidade, por conterem metais tóxicos e acidez elevada, ou ao coprocessamento em cimenteiras. A eletrorremediação de catalisadores, em desenvolvimento nos laboratorios do GEA na UFPR, tem apresentado melhorias na área superficial e na remoção de contaminantes metálicos dos catalisadores desativados. Assim o objetivo desse trabalho e estudar os mecanismos que recuperam a capacidade catalitica do catalisador apos o processo de eletrorremediacao. Através da eletrorremediacao o catalisador tratado poderia retornar para a refinaria de origem ou para uma refinaria com um corte diferente de petróleo; também os elementos metálicos removidos do catalisador poderiam ser reaproveitados trazendo ganhos econômicos. O tratamento eletroquímico pode diminuir a periculosidade do resíduo e/ou aumentar o ciclo de vida do catalisador; diminuindo o impacto ambiental do setor. Os resultados indicam que a remedição eletrocinetica promoveu uma reorganização nos componentes do catalisador, melhorando sua cristalinidade e diminuindo os contaminantes presentes, especialmente nas remediações acidas. Os espectros de RMN 27Al mostraram que as remediações acidas (com acido sulfúrico ou acido cítrico) lixiviaram seletivamente espécies de alumínio tetraédricos e penta-coordenados. A remediacao com citrato de sódio manteve a proporção entre o alumínio nas posições tetraedrais/octaedrais, removendo apenas espécies de alumínio penta-coordenadas (típicas de um ambiente químico altamente distorcido). A avaliação da acidez através do Infravermelho com piridina adsorvida mostrou a geração de sítios ácidos de Bronsted (especialmente nas remediacoes acidas) e a variação na forca dos sítios de Bronsted e Lewis, que foi inversamente proporcional a temperatura de dessorcao. A remoção de metais (vanádio e lantânio) dos catalisadores foi estimada por FRX e EDS e foi proporcional ao potencial utilizado e a concentração e forca do eletrólito empregado. As analises por EPR indicaram que o vanádio encontra-se em estado de oxidação +4 e simetria C4v, possivelmente em coordenação octaédrica com oxigênios da matriz ou da zeolita, ocupando posições na estrutura do catalisador. Os testes de conversão mostraram elevada atividade e baixa seletividade para o catalisador remediado com acido sulfúrico, enquanto o remediado com citrato de sódio gerou mais gasolina e menos coque em relação ao desativado de partida. A recuperação parcial da atividade catalítica dos catalisadores apos a eletrorremediação foi devido ao aumento da área superficial e remoção de contaminantes, que permitiram uma melhor acessibilidade aos sítios ácidos disponíveis para catalise. Palavras-chave: Remediacao eletrocinetica. Catalisador desativado de FCC. Ácidos de Bronsted. Ácidos de Lewis.
Abstract: The rising generation of deactivated catalyst in Fluidized Catalytic Cracking units and its high importance in Brazilian refineries motivates studies for its reuse. After use and deactivation of the catalysts, these are intended to Class I landfills due to its dangerousness, their toxic metals and high acidity, or yet coprocessing in cement factories with some restrictions. The electroremediation technique in development at the GEA laboratories at UFPR, has shown improvements in surface area and in the removal of metallic contaminants from spent catalysts. So the aim of this work is to study the mechanisms that recover the catalytic ability of the catalyst after electroremediation process. Through electroremediation the treated catalyst might return to the original refinery or to a refinery with a different oil cut; the metallic elements removed from the catalyst could also be reused bringing economic gains. The electrochemical treatment can reduce the hazard of the waste and / or increase the life cycle of the catalyst; reducing the environmental impact of the sector. The results indicated that the electrokinetic remediation promoted a reorganization of the catalyst components, improving crystallinity and reducing contaminants, especially in acidic solutions. The 27Al NMR spectra showed that the acid remediation (sulfuric acid or citric acid) selectively leached tetrahedral and penta-coordinated aluminum species. The remediation with sodium citrate kept the ratio of aluminum in tetrahedral / octahedral positions, removing only penta-coordinated aluminum species (typical of a highly distorted chemical environment). The evaluation of acidity by pyridine adsorbed Infrared showed the generation of Bronsted acid sites (especially in the acid remediation), and the variation in the strength of Bronsted and Lewis sites, which was inversely proportional to the desorption temperature. The removal of metals (vanadium and lanthanum) of the catalyst was estimated by XRF and EDS and was proportional to the electric potential and the concentration and the strength of the electrolyte used. The EPR analyzes indicated that the vanadium is in oxidation state +4 and C4V symmetry, possibly in octahedral coordination with oxygen atoms of the matrix or zeolite, occupying positions in the catalyst structure. Conversion tests showed high activity and low selectivity for the catalyst remedied with sulfuric acid, while the remedied with sodium citrate produced more gasoline and less coke in relation to the starting deactivated. The partial recovery of the catalytic activity of the catalysts after electrorremediation was due to increased surface area and removal of contaminants, which allowed easier access to the acid sites available for catalysis. Keywords: Electrokinetic remediation. FCC deactivated catalyst. Bronsted and Lewis acids.
Jennings, G. "Ultra-violet photoelectron spectroscopy of BCC- and FCC- iron." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306636.
Full textBacroix, Brigitte. "Prediction of high temperature deformation textures in FCC metals." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74036.
Full textNazarov, Andrei V., Alexander A. Mikheev, Irina V. Valikova, Aung Moe, and Alexander G. Zaluzhnyi. "Kinetic of void growth in fcc and bcc metals." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193483.
Full textQiu, Yishan. "Finite element simulation of plastic deformation of FCC polycrystals." Thèse, Université de Sherbrooke, 1995. http://savoirs.usherbrooke.ca/handle/11143/1648.
Full textRibeiro, Pleycienne Trajano. "Modelagem e controle de unidades de craqueamento catalitico - FCC." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266266.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Por representar um importante processo de conversão da indústria petroquímica, o craqueamento catalítico é um dos processos de conversão mais estudados. Nele, moléculas de alto peso molecular são quebradas em moléculas com menor peso molecular, obtendo-se assim produtos economicamente mais desejáveis. Os estudos do processo, de sua modelagem matemática e dos seus sistemas de controle, podem garantir o conhecimento necessário para alcançar condições operacionais ótimas que levem à máxima conversão da carga. Neste contexto, este trabalho teve como objetivos: a pesquisa e utilização de uma modelagem matemática para o conversor FCC (Fluid Catalytic Cracking); o estudo do processo sob influência de um controlador PID clássico, muito utilizado em refinarias; a estruturação de uma rede neural artificial (RNA) e o seu posterior uso como modelo interno de um controlador avançado tipo preditivo desenvolvido a partir dos estudos feitos no processo de craqueamento catalítico. Em paralelo, foi cirada uma ferramenta de simulação que possibilitou o meio mais amigável e prático para realização de todas as simulações necessárias para o desenvolvimento do presente trabalho. O FCCGUI (Fluid Catalytic Cracking Graphical User Interface), nome dado ao simulador, proporciona a escolha de parâmetros de simulação, diferentes estruturas de controle (PID, DMC e MPC - baseado em redes neurais), a visualização de diferentes variáveis manipuladas, controladas e sinais de válvulas e facilidades para perturbar o sistema. Através das simulações foi possível acompanhar o comportamento das variáveis de processo em diferentes condições testadas, realizar a estruturação da rede neural e obter as respostas das variáveis controladas para os dois tipos de controladores estudados. Os resultados obtidos foram bastante satisfatórios, visto que a modelagem matemática escolhida representa bem o sistema e o controlador MPC-Neural desenvolvido se mostrou eficiente, por conseguir manter o processo estável e próximo ao set point, mesmo após a aplicação de perturbações no processo
Abstract: Catalytic cracking is one of the most studied conversion processes due its importance in the petrochemical industry. In this process high weight molecules are broken into lighter ones, yielding more economically valuable products. The study about the process, its mathematical modeling, and its control systems may guarantee the necessary knowledge needed to reach optimal operational conditions which lead to maximum load conversion. In this context, the present work thesis has as main objectives the research and use of a mathematical modeling for a FCC (Fluid Catalytic Cracking) conversion unit, the study of the system under PID control loop widely used in refineries, structuring of an artificial neural network (ANN) with its use as an internal model of a predictive control system developed for catalytic cracking. Parallel to this, it was developed a computational tool which in a friendly and practical way made possible to carry out simulations needed to accomplish this work. FCCGUI (Fluid Catalytic Cracking Graphical User Interface), name given to this simulator, allows to choose simulation parameters, different control systems (PID, DMC, and MPC-ANN Based), graphical visualization of many different variables, such as manipulated and controlled variables plus valve signals, also it allows for and easy means for disturbing the system while the simulation continues. Through the simulations it was possible to follow the behavior of many process variables under different tested operational conditions, to structure the neural network, and to obtain controlled variables responses for both types of control systems studied. The obtained results were quite satisfactory since the chosen mathematical modeling represents well the system and the developed MPC-ANN controller showed to be efficient to maintain the process stable and close to the set points even after the introduction of disturbances in the process. Taking all these into account, compared to PID controller, MPC-ANN showed to be less oscillatory and to be more effective
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
Nazarov, Andrei V., Alexander A. Mikheev, Irina V. Valikova, Aung Moe, and Alexander G. Zaluzhnyi. "Kinetic of void growth in fcc and bcc metals." Diffusion fundamentals 6 (2007) 28, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14203.
Full textYellakara, Ranga Nikhil. "Computational Study of Dislocation Based Mechanisms in FCC Materials." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699921/.
Full textLea, Lewis John. "Structural evolution in the dynamic plasticity of FCC metals." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273897.
Full textMorales, Soler Mauricio Enrique. "Atomic scale study of mechanical spectroscopy in FCC metals." Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/143495.
Full textLa fricción interna corresponde a la capacidad de los materiales de disipar la energía de ondas de sonido. Esta capacidad depende del tipo de material así como del tipo y cantidad de defectos que contenga. Durante muchos años se ha utilizado la espectroscopía mecánica para obtener información del material a través de distintos experimentos, midiendo por ejemplo la fricción interna de un material específico. A pesar de la capacidad para medir fricción interna, hasta ahora es difícil conocer con precisión cuales son los mecanismos microscópicos que dan origen a la disipación de energía al interior del material. De particular interés es un pico en la curva de disipación interna versus temperatura llamado pico de Bordoni. La evidencia sugiere que la generación de este pico se debe a propiedades de las dislocaciones. Modelos teóricos que usan mecánica del continuo permiten una descripción cualitativa, pero no cuantitativa, del efecto. Hasta ahora se ha estudiado el pico de Bordoni desde el punto de vista experimental y desde la mecánica del contínuo. En este trabajo se propone estudiar este efecto desde las simulaciones atomísticas a través de dinámica molecular. Para ello se generó una muestra de cobre de 892800 átomos con dos dislocaciones ancladas y se generaron ondas de corte en el material. Se midió la tensión generada en la muestra y se encontraron las curvas de tensión-deformación. Luego se estudió la disipación de energía generada por la interacción de las ondas con las dislocaciones a través de una posible histéresis en las curvas de tensión-deformación. Estas simulaciones se realizaron a las temperaturas de 0, 50, 100, 150, 200 y 250 K, con períodos de 125 ps y 38 ps y un máximo de deformación de 0.0008 y 0.008. Para estimar el orden de magnitud esperado para la respuesta del sistema se usó un modelo de cuerda sobreamortiguada, lo que también permitió estimar el período de forzamiento para el cual las pérdidas deberían ser máximas. Todo esto llevó a una estimación del cuociente entre energía disipada por ciclo y energía acumulada máxima del orden de 10^{-4} lo cual se ajusta a los resultados experimentales. Para estimar el valor de los parámetros que aparecen en el modelo analítico se realizaron simulaciones con las dislocaciones desancladas. Dentro de la precisión numérica utilizada, no se encontró histéresis. Se deduce que la barrera de Peierls es muy pequeña para permitir detección de la histéresis. Se establece una cota para la precisión en las mediciones para cuantificar la fricción interna en el futuro. Posibles direcciones de trabajo futuro incluyen la disminución de las fluctuaciones en las mediciones de la tensión, lo que se podría lograr con un mayor número de ciclos generados en las ondas de corte y promediando sobre muchas realizaciones. Otra opción es realizar las simulaciones en otros materiales, con mayores coeficientes de fricción, para aumentar la energía disipada.
Aleknevičius, Marius. "The influence of oil cracking catalyst waste on the properties of refractory castables." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20110120_134405-85598.
Full textNaftos krekinge naudotas katalizatorius yra ceolitinė medžiaga, kurios unikalios savybės mažai išnaudojamos cementinių medžiagų gamybos technologijoje. Ugniai atspariuose betonuose naudojami įvairūs priedai-modifikatoriai yra labai brangūs, todėl naudoto katalizatoriaus panaudojimas, kaip modifikuojančio betono savybes priedo, turi ne tik ekologinį (atliekų utilizavimas) bet ir ekonominį pagrindą. Vykdant šį darbą sukurti vidutinio cemento kiekio ugniai atsparūs šamotbetoniai su 70 % ir 40 % aliuminio oksido turinčiais aliuminatiniais cementais ir naudoto katalizatoriaus priedu atitinkamai 2,5 % ir 5,0 %. Darbe taip pat atskleistas efektyvus katalizatoriaus poveikis aliuminatinio cemento hidratacijai, cemento akmens struktūros susidarymui kietėjimo metu ir jos pokyčiams veikiant aukštoms temperatūroms.
Aleknevičius, Marius. "Naftos krekinge naudoto katalizatoriaus poveikis ugniai atsparių betonų savybėms." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20110120_134413-03760.
Full textFluidized bed catalytic cracking catalyst waste is a zeolite material. Its unique properties are underused in cementitious materials production technology. Various additives, modifiers used in refractory castables are very expensive, so the use of catalyst waste as a modifying additive of castable properties has not only an ecological (waste recycling) but also an economical basis. Medium cement refractory castable was developed using 70 % and 40 % of aluminium oxide containing aluminate cement and catalyst waste additive, respectively 2,5 % and 5,0 %. The work also reveals an efficient effect of catalyst waste on alumina cement hydration, structure formation during cement solidification and after treatment at high temperature.
Martignoni, Waldir Pedro. "Modelling and simulation of FCC riser reactors, an heterogeneous approach." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq31116.pdf.
Full textKomarasamy, Mageshwari. "Deformation Micro-mechanisms of Simple and Complex Concentrated FCC Alloys." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822829/.
Full textSouza, Thiago Xavier Rocha de. "Propriedades magnéticas do modelo de Hubbard em estruturas tipo FCC." Universidade Federal de Sergipe, 2012. https://ri.ufs.br/handle/riufs/5345.
Full textThe study about magnetic properties of strongly correlated electrons has been an problem of interest in physics by the great technological importance of various materials with this characteristic. A well-known theoretical approach, known as the Hubbard model, has been used in an attempt to describe such phenomena. This model considers the interactions and electron mobility in a simplified way for describing phenomena like itinerant magnetism and the metal-insulator transition. In this study were analyzed the thermodynamic clusters properties of structures with fcc lattice symmetry containing 4, 5, 6, 7 and 8 sites. An exact numerical diagonalization method was used, where the subspaces of the problem were separatly analyzed and put together on, which is a procedure that reduces the processing data time. In order to improve the diagram of quantum states also carried out a ground state analysis of the clusters, known in the literature and obtained from systems with 4, 5 and 6 sites. On this subject a new diagram was developed showing the quantum states transition using the Lanczos method, applied to clusters with 4 to 8 sites in this case. Finally, a comparison was made between the thermodynamic properties and the results found in the new quantum state diagram. The agreement between them is good.
O estudo de propriedades magnéticas de elétrons fortemente correlacionados tem sido um problema de interesse da física pela grande importância tecnológica de vários materiais com essa característica. Uma famosa abordagem teórica, conhecida como modelo de Hubbard, vem sendo utilizada na tentativa de descrever esse tipo fenômeno. Esse modelo considera interações e a mobilidade eletrônica descrevendo de forma simplificada fenômenos como magnetismo itinerante e transição metal-isolante. Neste trabalho foram analisadas propriedades termodinâmicas de clusters de estruturas com simetria da rede fcc contendo 4, 5, 6, 7 e 8 sítios. Foi utilizado um método de diagonalização numérica exata, onde os subespaços do problema foram analisados separadamente e reunidos posteriormente, procedimento que reduz o tempo de processamento dos dados. Foi também realizada uma análise do estado fundamental dos clusters com o intuito de aprimorar o diagrama de estados quânticos, conhecido na literatura, obtido a partir de sistemas com 4, 5 e 6 sítios. Sobre esse assunto, foi desenvolvido um novo diagrama que indica a transição de estados quânticos a partir da utilização do método de Lanczos, neste caso, aplicado a clusters de 4 a 8 sítios. Por fim, foi feita uma análise comparativa entre as propriedades termodinâmicas e os resultados encontrados no novo diagrama de estados quânticos que mostraram boa coerência entre si.
Rohatgi, Aashish. "A microstructural investigation of shock-loading effects in FCC materials /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9944211.
Full textLiu, Gang. "Nucleation and cross-slip of partial dislocations in FCC metals." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1957327601&SrchMode=2&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1269015486&clientId=48051.
Full textIncludes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 20, 2010). Includes bibliographical references. Also issued in print.
Kempton, James Russell. "Sites and diffusion of muons in FCC metal hydride systems." W&M ScholarWorks, 1987. https://scholarworks.wm.edu/etd/1539623772.
Full textSvenningsson, Leo. "Fourier transform of BCC andFCC lattices for MRI applications." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257148.
Full textCristina, Bezerra Azedo de Melo Ana. "Validação de modelos matemáticos para descrever a fluidodinâmica de um riser a frio utilizando atenuação Gama." Universidade Federal de Pernambuco, 2004. https://repositorio.ufpe.br/handle/123456789/9568.
Full textO comportamento fluidodinâmico do riser de um modelo a frio tipo FCC foi investigado por meio das medidas da distribuição da concentração do catalisador com atenuação gama e simulação com modelo matemático. No riser do modelo a frio, MEF, com 0,032 m de diâmetro 2,3 m de comprimento circula o leito fluidizado cujos componentes são ar e catalisador de FCC. A unidade MEF opera com controle automático e instrumentos de medidas das variáveis fluidodinâmicas. A distribuição axial da concentração do catalisador foi medida utilizando-se uma fonte de Am-241 e detector de NaI(Tl) associado a multicanal com software de aquisição e avaliação de dados. O MEF foi adaptado para a validação de modelo fluidodinâmico que descreve o escoamento no riser, como por exemplo, a introdução de injetor para controle do fluxo de sólidos em circulação. Modelos matemáticos foram selecionados na literatura, analisados e testados para simular a fluidodinâmica do riser. Foi estudada e implementada uma metodologia para validar modelos fluidodinâmicos. As etapas do trabalhos foram desenvolvidas de acordo com a metodologia de validação, como planejamento de dados experimentais, estudo das equações que descrevem a fluidodinâmica, aplicação de solvers computacionais e avaliação da simulação em comparação com os dados experimentais. Corridas foram realizadas com as condições do MEF definidas para medir a concentração do catalisador e sendo medidas simultaneamente as variáveis fluidodinâmicas, velocidade dos componentes e variação da pressão no riser. Em seguida foram comparados valores simulados e valores experimentais, com o tratamento estatístico dos dados, visando a precisão requerida para validar o modelo fluidodinâmico. Os testes de comparação entre dados experimentais e simulados foram realizados sob os critérios de validação. O comportamento fluidodinâmico do riser foi analisado, os resultados e a concordância com a literatura foram discutidos. O modelo adotado foi validado nas condições de operação do riser do MEF, para uma faixa de vazão do gás de 3 a 6 m/s e o valor da razão de escorregamento entre 1 e 2
Chmyrov, Volodymyr. "Fluorescence fluctuation studies of biomolecular interactions in solutions, biomembranes and live cells." Doctoral thesis, KTH, Experimentell biomolekylär fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187708.
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Isler, Jeremy Payton. "Interactions of Lanthanides and Liquid Alkali Metals for "Liquid-Like" Lanthanide Transport in U-Zr Fuel." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492607350430645.
Full textBoum, Alexandre Teplaira. "Commande prédictive d'un craqueur catalytique à lit fluidisé avec estimation des paramètres clés." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0033/document.
Full textFluid catalytic cracking (FCC) is one of the most important processes in a modern refinery and is of essential economic importance. The FCC operation presents difficulties related to its complexity. The study was related to its simulation, multivariable control and estimation of key parameters. After a litterature review of the FCC, the different approaches of modelling and cracking kinetics, a FCC model that takes into account the important dynamics was chosen for model predictive control purposes. The riser simulation was carried out for different cracking models and shows great differences between these models, which makes it difficult to define a general riser model for the FCC. Besides the number of lumps, differences deal with the global heat of reaction, the coke formation laws and its deactivation functions. Linear and nonlinear model predictive algorithms were used for FCC control taking into account its multivariable nature and the constraints imposed on the manipulated variables. The controlled outputs, temperature at the riser top and temperature in the regenerator were maintained close to their respective set points in regulation and tracking modes while respecting the constraints on the two manipulated variable, the flow rate of regenerated catalyst and the flow rate of air entering the regenerator. A control with three manipulated variables including the feed flow rate was also successfully tested. Linear predictive control with an observer gave better results than linear quadratic control. Nonlinear predictive control was tested but presents problems for real time implementation. The estimation of coke on the catalyst was carried out using extended Kalman filter, but the estimation errors are important, probably due to an insufficient choice of measurements. The overall study showed that advanced predictive control of the FCC is efficient and must be recommended, but it can still be improved upon particularly by its tuning and state estimation
Silva, Douglas Luís da. "Recuperação de terras raras contidas em catalisadores exauridos utilizados no craqueamento do petróleo (FCC), e em pós-fosfóricos de lâmpadas fluorescentes descartadas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-21062017-112107/.
Full textSynthetic zeolites containing rare earths (RE) are the major components of FCC (Fluid Catalytic Cracking) catalysts used in petroleum cracking, where the percentage of such elements is about 5%. RE ions improve the thermal and hydrothermal stability of zeolites-Y during the petroleum refining process. The Brazilian production of these catalysts is around 25 thousand tons per year, requiring 900 tons of lanthanum oxide in the same period. Currently, China is responsible for 90% of the world production and market of RE. Since 2010, China controls the prices of RE elements and substantially reduced the exportation quota. For instance, by the end of 2011 the price of lanthanum was risen by more than 20 times. In this context, the search for recycling materials that have rare earths in their constitution becomes crucial, as is the case of the FCC catalysts from the cracking of petroleum. Another source that deserves significant attention is the phosphoric powders that generate white light in fluorescent lamps, which were also investigated in this work. Rhodia from the Solvay group has already begun the recovery of rare earths in phosphoric powders. The main RE used in fluorescent lamps are La, Ce, Eu, Tb and Y, which occur as Y2O3: Eu3+, BaMgAl10O17:Eu2+ and LaPO4:Ce3+, Tb3+. Eu, Tb and Y are high-value elements, representing by 5 20% of the total mass of phosphoric powders. Therefore, the aim of this work was to develop economically feasible and environmental friendly methodologies for the separation and recovery of RE ions from zeolite-Yin deactivated FCC catalysts and from fluorescent lamp phosphors. To this end, we firstly performed a preliminary characterization of the components of deactivated FCC catalysts. The following steps comprised the development of chemical separation methodologies to obtain rare earth elements and their characterization by several techniques such as photoluminescence spectroscopy, X-ray fluorescence, complexation titration, scanning electron microscopy and infrared spectroscopy
Ahmadi, Motlagh Amir Hossein. "CFD simulation of two- and three-phase flow in FCC reactors." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52621.
Full textApplied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
Lin, Peter Keng-Yu. "Evolution of grain boundary character distributions in FCC and BCC materials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ27994.pdf.
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