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Process intensification tools, such as the capillary reactor, offer several benefits to the chemical process industries due to the well-defined high specific interfacial area available for heat and mass transfer, which increases the transfer rates, and due to low inventories, they also enhance the safety of the process. This has provided motivation to investigate three such tools, namely the capillary microreactor, spinning disc and rotating tube reactors, in this study. / The gas-liquid slug flow capillary microreactor intensifies reactor performance through internal circulation caused by the shear between the continuous phase/wall surface and the slug axis, which enhances the diffusivity and consequently increases the reaction rates. However, integrating the complex hydrodynamics of this reactor with its chemical kinetics is a mathematically challenging task. Therefore, in this study, a simple-to-complex approach, using a set of state-of-the-art computational fluid dynamic tools, has been used. Firstly, simulations were performed without any chemical reaction to ascertain the extent of slug flow regime. The model also clearly captured the slug flow generation mechanism which can be used to structurally optimize the angle of entry in these reactors. Finally, the hydrodynamic model was also capable of estimating the pressure drop and slug lengths. After successfully simulating the hydrodynamics of the system, a reaction model was incorporated to study the chemical reaction kinetics. The results were compared with the published experimental work and were found to be in good agreement. / The spinning disc reactor utilizes the centrifugal and shear forces to generate thin liquid films characterized with intense interfering waves. This enables a very high heat transfer coefficients to be realized between the disc and liquid, as well as very high mass transfer between the liquid and the bulk gas phase. The waves formed also produce an intense local mixing with very little back mixing. This makes a spinning disc reactor an ideal contactor for multiphase processes. The focus of this study has been to elucidate the hydrodynamic behaviour of the liquid film flow over the horizontal spinning disc. Investigations were also performed to elaborate the local and overall hydrodynamic characteristics of a fully developed spinning disc reactor. Simulation results showed a continuous linear liquid film on the horizontal spinning disc and intense mixing performance in the annulus of the reactor around the disc surface. Finally, the film thickness data from the simulations were compared with the limited amount of data available for this novel process. / Rotating tube reactor also uses centrifugal forces to generate the liquid film and a high degree of mixing along with an improved control over the reactant retention times. In this work we have conducted a CFD analysis to understand the hydrodynamics of this new technology for future developments.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Vibration-based fault diagnosis (FD) with a simple spectrum can be complex, especially when considering FD of rotating machinery with multiple bearings like a multi-stage turbine. Various studies have sought to better interpret fault spectra, but the process remains equivocal. Consequently, it has been accepted that the simple spectra requires support from additional techniques, such as orbit analysis. But even orbit analysis can be inconclusive. Though promising, attempts at developing viable methods that rival the failure coverage of spectrum analysis without gaining computational complexity remain protracted. Interestingly, few researchers have developed FD methods for transient machine operation, however, these have proven to be involved. Current practices limit vibration data to a single machine, which usually requires a large unique data history. However, if sharing of data between similar machines with different foundations was possible, the need for unique histories would be mitigated. From readily available works, this has not been encountered. Therefore, a simple but robust vibration-based approach is warranted. In light of this, a novel on-bearing vibration response integration approach for condition monitoring of shaft-related faults irrespective of speed and foundation type is proposed in the present study. Vibration data are acquired at different speeds for: a baseline, unbalance, bow, crack, looseness, misalignment, and rub conditions on three laboratory rigs with dynamically different foundations, namely: rigid, flexible support 1 (FS1) and flexible support 2 (FS2). Testing is done on the rigid rig set up first, then FS1, and afterwards FS2. Common vibration features are computed from the measured data to be input to the proposed approach for further processing. First, the proposed approach is developed through its application to a machine at a steady speed in a novel Single-speed FD technique which exploits a single vibration sensor per bearing and fusion of features from different bearings for FD. Initially, vibration features are supplemented with bearing temperature readings with improved classification compared to vibration features alone. However, it is observed that temperature readings are insensitive to faults on the FS1 and FS2 rigs, when compared to vibration features, which are standardised for consistent classification on the different rigs tested. Thus, temperature is not included as a final feature. The observed fault classifications on the different rigs at different speeds with the standardised vibration features are encouraging. Thereafter, a novel Unified Multi-speed FD technique that is based on the initial proposed approach and which works by fusion of vibration features from different bearings at different speeds in a single analysis step for FD is proposed. Experiments on the different rigs repeatedly show the novel Multi-speed technique to be suitable for transient machine operation. Then, a novel generic Multi-foundation Technique (also based on the proposed approach) that allows sharing of vibration data of a wide range of fault conditions between two similarly configured machines with similar speed operation but different foundations is implemented to further mitigate data requirements in the FD process. Observations made with the rigs during steady and transient speed tests show this technique is applicable in situations where data history is available on one machine but lacking on the other. Comparison of experimental results with results obtained from theoretical simulations indicates the approach is consistent. Thus, the proposed approach has the potential for practical considerations.

Submitted by Mateus de Andrade Zanitti (mateuszanitti@hotmail.com) on 2018-06-29T14:33:25Z No. of bitstreams: 1 Mateus_Zanitti.pdf: 5438696 bytes, checksum: 7b89dea41803feb908ac9a925a1476a6 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-06-29T14:46:24Z (GMT) No. of bitstreams: 1 zanitti_ma_me_ilha.pdf: 5727118 bytes, checksum: 3fcb4fd3093903b37c0ec52a3df572ff (MD5) / Made available in DSpace on 2018-06-29T14:46:24Z (GMT). No. of bitstreams: 1 zanitti_ma_me_ilha.pdf: 5727118 bytes, checksum: 3fcb4fd3093903b37c0ec52a3df572ff (MD5) Previous issue date: 2018-06-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho trata do desenvolvimento, análise e validação das equações do movimento de vigas flexíveis girantes formulada pelo método dos Elementos Finitos. A modelagem da viga é feita através do modelo proposto de viga de Euler-Bernoulli e a deformação é representada pelo tensor de deformação de Green-Lagrange. As equações globais para os modos longitudinal, lag e flap são obtidas pelo método de energia de Lagrange e a discretização é feita pelo método dos Elementos Finitos. São propostos modelos de viga elementar com dois e três graus de liberdade por nó e sua validação é feita, num primeiro momento, pela comparação das frequências naturais e posteriormente pela resposta, em regime transiente, dos deslocamentos da viga, através da comparação dos resultados obtidos com os dados disponíveis na literatura, sendo que a influência do acoplamento entre os modos longitudinal e lag é investigada para a dinâmica em regime transiente. O trabalho termina comentando as potencialidades da proposta apresentada, discutindo as facilidades e dificuldades encontradas na sua implementação e apontamentos para o desenvolvimento de trabalhos futuros. / This work deals with the development, analysis and validation of the motion equations of the flexible rotating beams formulated by the Finite Element method. The beam modeling is done through the proposed Euler-Bernoulli beam model and the deformation is represented by the Green-Lagrange deformation tensor. The global equations for the longitudinal, lag and flap modes are obtained by the Lagrange energy method and the discretization is done by the Finite Element method. A discrete beam model with two and three degrees of freedom per node is proposed and its validation is done, firstly, by comparing the natural frequencies and later by the transient response of the beam displacements, by comparing the results obtained with the data available in the literature, and the influence of the coupling between the longitudinal and lag modes is investigated for the transient dynamics. This work is concluded presenting the potentialities of the design methodology proposed and future developments to be implemented.

A pesquisa apresenta o fenômeno da rotatividade, composta por evasão, trocas e outras saídas, em 193 assentamentos do Rio Grande do Sul, com ênfase na evasão de lotes. Esta é entendida como a saída do Programa de Reforma Agrária e foi correlacionada com 16 variáveis: a) crédito instalaçãomodalidade apoio; b) crédito instalação-modalidade materiais de construção; c)PRONAF A; d)percentual de lotes sem água; e) sem luz; f) sem casa; g) qualidade das estradas internas; h) estradas externas; i) qualidade dos solos; j) tipo de prestadora da assistência técnica, l) executor do assentamento, m) ano de implantação; n) tipo de público; o) a região de implantação; p) religião do evadido; e q) seu estado civil. Estas variáveis e a evasão foram obtidas com dados secundários no INCRA e no GRAC, o órgão de terras estadual. As duas últimas variáveis foram testadas somente em dois estudos de casos, realizados na forma de etnografias. Isto foi necessário para dar conta da hipótese central, de que a evasão é facilitada em situações de baixa coesão social, haja vista que quase todas as variáveis se referem à dimensão material da questão, notadamente problemas de crédito e infra-estrutura. Para a compreensão dos processos que levam à coesão social nos assentamentos, lançamos mão do aporte teórico da sociologia da crítica, com contribuições pontuais de outros autores, tais como Bourdieu, Elias, Wolf e Martins, entre outros, além da antropologia, principalmente através da noção de reciprocidade, neste caso, com o aporte essencial de Sabourin e Caillé. Os resultados obtidos revelam uma estimativa da média de evasão nos assentamentos de 22 %, porém com diferenças regionais grandes, onde, na metade norte do Estado, encontramos algo em torno de 10%, e na metade sul, quase 30%. Não obtivemos correlação de nenhuma variável da chamada dimensão material com a evasão, ao passo que verificamos a centralidade das relações de reciprocidade, em especial o parentesco, na forma da família extensa e do compadrio e das relações com os vizinhos, “gaúchos” e fazendeiros, na construção da coesão social e no estancamento da evasão. Esta se dá concomitante à contenção de conflitos, onde a Assembléia de Deus, Igreja Pentecostal, assume posição preponderante nos casos estudados. Os evangélicos, assim como os casados, tendem a uma menor rotatividade e evasão, pois caminham para um maior fortalecimento de laços sociais, quando comparados com os solteiros e os católicos. Por último, discutimos o papel dos mediadores, principalmente a assistência técnica, os técnicos dos órgãos de terra e as lideranças do MST, num ambiente de disputas e acordos entre projetos corporativos, por nós denominados: projeto tradicional-camponês, projeto socialista-coletivista e projeto empresarial, além das estratégias não corporáveis, que podem levar ao rentismo e à evasão propriamente. / The research presents the rotating phenomenon, composed by escape, exchange and others exits, in 193 settlements of Rio Grande do Sul, with emphasis in parcels escape. It is understood like the land reform escape and was correlated with 16 factors: a) install credit- support modality, b) install credit – construction materials modality, c) PRONAF A, d) percentage of parcels without water, e) without light parcels, f) percentage of parcels without house, g) internal road quality, h) external road quality, i) soil quality, j) technical assistance kind l) settlement executor, m) implant year, n) public type o) implant region, p) escaped religion, q) escaped civil state. These factors and the escape were got in secondary dates of INCRA and GRAC, the state land institution. The two last factors were tested only in ethnographic cases. It was necessary to respond the central hypothesis, where the escape is facilitated in low social cohesion situations, because almost all factors refers to the question material dimension, in particular, infra-structure and credit problems. To social cohesion process understanding, we made use the criticism sociology theoretic support, with other authors punctuals contributions, like Bourdieu, Elias, Wolf and Martins, among others; beyond the anthropology, mainly throw the reciprocity notion, in this case with the Sabourin and Caillé essential support. The results reveal a 22% settlement escape average estimative, however, with great regional differences, where, in state half northern, we found nearly 10%, and in half southern, almost 30%. We did not get correlation of no material dimension factors with escape, but we verified the reciprocity relations centrality, in special, the kinship, in extend family and “compadrio” form, and the neighbor relationship, “gaúchos” and farmers, in the social cohesion construction and in the escape stopping. It occur concomitant the contention conflict, where God Assembly, a Pentecostal Church, assumes a preponderant position in the studied cases. The evangelicals, just like the married, tend to low escape and rotation, because they lead to higher social laces strengthening, in comparison with catholic and singles. Finally, we discussed the mediator paper, mainly the technical assistance, land institutions technical and MST leaders, in a corporation projects struggle ambient, we denominated: peasant–traditional project, collectivist-socialist project and enterprise project, beyond the no corporeal strategies, that can lead to rental and escape.

CAMPOS, Othon Souto. Estudo Mecanístico da Eletrodeposição de Cádmio em Meio de Sulfato Ácido. 2011. 46 f. Dissertação (Mestrado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2011. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-02T19:41:14Z No. of bitstreams: 1 2011_dis_oscampos.pdf: 938891 bytes, checksum: 170c80aaa846defc16b0b360c53792fb (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-07-20T20:01:55Z (GMT) No. of bitstreams: 1 2011_dis_oscampos.pdf: 938891 bytes, checksum: 170c80aaa846defc16b0b360c53792fb (MD5) / Made available in DSpace on 2016-07-20T20:01:55Z (GMT). No. of bitstreams: 1 2011_dis_oscampos.pdf: 938891 bytes, checksum: 170c80aaa846defc16b0b360c53792fb (MD5) Previous issue date: 2011 / This work describes a mechanistical proposition for cadmium electrodeposition in acid sulfate medium on platinum substrate using electrochemical techniques. The cadmium electrodeposition studies were carried in sodium sulfate 1 mol L–1 medium containing cadmium sulfate 10–2 mol L–1, which the pH of the solutions were adjusted with analytical grade sulfuric acid. The pH interval of the work solutions were ranged between 1 and 3. In all studied medium, the potentiostatic polarization curves showed a diffusional plateau which obeys the Levich equation. The interfacial pH studies showed the influence of acid–base equilibrium of bisulfate ion with the formation of a coordination compound Cd(HSO4)+ in platinum electrode. It is proposed that the cadmium ion associated in acid–base equilibrium of bisulfate ion, deposits as cadmium bisulfate at an irreversible step, and followed by a reversible metallic deposition of cadmium with the leaving of bisulfate ion, and this step is slower than the first one. Then, a mathematical model was calculated for the mechanism proposed, and qualitative studies were carried regarding to the polarization curve and electrochemical impedance spectroscopy behavior. / Este trabalho descreve uma proposição mecanística para a deposição de cádmio em meio de sulfato ácido sobre substrato de platina utilizando técnicas eletroquímicas. Os estudos de eletrodeposição de cádmio foram feitas em meio de sulfato de sódio 1 mol L–1 contendo 10–2 mol L–1 de sulfato de cádmio, em que o pH das soluções foi ajustado com ácido sulfúrico PA. O intervalo de pH das soluções de trabalho foi variado entre 1 e 3. Em todos os meios estudados, as curvas de polarização potenciostática mostraram a formação de um patamar difusional que obedece a equação de Levich. Os estudos de pH local revelaram a influência do equilíbrio ácido–base do íon bissulfato com formação de compostos de coordenação Cd(HSO4)+ no eletrodo de platina. Propõe-se que o íon cádmio, associado ao equilíbrio ácido–base do íon bissulfato, deposita como bissulfato de cádmio numa etapa irreversível, e seguida pela deposição de cádmio metálico reversível com a saída do íon bissulfato, sendo esta última etapa mais lenta que a primeira. Desse modo, foi calculado um modelo matemático para o mecanismo proposto, sendo realizados estudos qualitativos em relação ao comportamento da curva de polarização e do espectro de impedância eletroquímica.