Thesis (Ed.D.)--University of Central Florida, 2008. / Adviser: Barbara A. Murray. Includes bibliographical references (p. 142-147).

Zugl.: Stuttgart, Univ., Diss., 2003.

Techn. Universiẗat, Diss., 2002--Berlin.

Techn. Universiẗat, Diss., 2001--Braunschweig.

Th. doct.-ing.--Toulouse, I.N.P., 1977. N°: 7.

Made available in DSpace on 2014-06-11T19:23:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-16Bitstream added on 2014-06-13T19:29:33Z : No. of bitstreams: 1 ravaro_lp_me_bauru.pdf: 967737 bytes, checksum: 4467c85af230546c2464c3465069b809 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dióxido de estanho (Sn'O IND. 2') é um semicondutor do tipo n, que é transparente na região do ultravioleta/visível. Possui muitas aplicações como, por exemplo, eletrodos transparentes, sensores de gás, coletores solares e dispositivos eletro-ópticos. Quando dopado com íons terras-raras, Sn'O IND. 2' pode ser utilizado na confecção de dispositivos para comunicação óptica, principalmente na forma de filmes finos. Os íons terras-raras têm grande relevância devido às transições eletrônicas, que vão do ultravioleta ao infravermelho próximo. Outro aspecto importante está ligado às características físico-químicas da suspensão coloidal de onde são depositados os filmes. Filmes obtidos com pH elevado da suspensão apresentam alta resistividade elétrica e baixa cristalinidade em relação aos filmes obtidos com pHs das suspensões ácidas. O nível mais profundo de energia dos defeitos em Sn'O IND. 2' foi alterado da energia de 140eV até 67eV para variação do pHs 11, até 6, de acordo com a avaliação da energia de ativação. Os difratogramas destes filmes indicam aumento de cristalinidade com a diminuição do pH. Xerogéis de Sn'O IND. 2':Er2% com alteração do pH em relação a suspensão neutra apresentaram espectro de emissão mais intenso na região infravermelha para a amostra com pH7 e um pequeno alargamento dos picos de emissão para a amostra com pH4 e mais acentuado para a amostra com pH11, em bom acordo com medidas de Raman. Relatamos também a emissão na região visível de filme fino de Sn'O IND. 2' dopado com 'Er POT. 3+', que é um formato adequado da amostra para confecção de dispositivos. / Tin dioxide (Sn'O IND. 2') is an n-type oxide semicondutor, which is transparent in the ultraviolet/visible range. It presents many types of applications, such as transparent electrodes, gas sensors, solar collectors and eletro-optical devices. When doped with rare-earth ions, Sn'O IND. 2' may be used to make optical communication devies, in the thin film configuration. Rare-earth ions have great relevance due to their electronic transitions, covering from ultraviolet to near infrared. Another important characteristic is related to the physical-chemical properties of the starting colloidal suspension to deposit the films. Films obtained with high pH of the suspension presents high electric resistivity and low crystallinity compared to films obtained with acid pH. The deepest energy level of the defects in Sn'O IND. 2' has been changed from the energy of 140 eV to 67 e V when the pH changes from 11 to 6. Diffractograms of these films show increase in the crystallinity with pH decrease. Sn'O IND. 2':Er2% xerogels with modified pH show more intense emission spectra in the infrared for sample with pH 7 and a low broadening of emission peaks for the sample with pH 4 and moer intense for pH 11, suggesting an ideal pH for higher emission samples, in good agreement with Raman shift spectra. We also report emission in the visible range from of an 'Er POT. 3+' -doped thin film, which is a very convenient form for devices fabrication.

Submitted by MATHEUS MIKAEL QUARTAROLI null (matheusquartaroli93@gmail.com) on 2018-03-29T18:49:36Z No. of bitstreams: 1 Dissertação.pdf: 2469304 bytes, checksum: e40aef3812815dd1e406d4e6b84b8256 (MD5) / Approved for entry into archive by Maria Marlene Zaniboni null (zaniboni@bauru.unesp.br) on 2018-04-02T18:28:06Z (GMT) No. of bitstreams: 1 quartaroli_mm_me_bauru.pdf: 2469304 bytes, checksum: e40aef3812815dd1e406d4e6b84b8256 (MD5) / Made available in DSpace on 2018-04-02T18:28:06Z (GMT). No. of bitstreams: 1 quartaroli_mm_me_bauru.pdf: 2469304 bytes, checksum: e40aef3812815dd1e406d4e6b84b8256 (MD5) Previous issue date: 2018-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esse trabalho buscou investigar os comportamentos dinâmicos de uma suspensão eletromecânica. Para a configuração dessa suspensão substitui-se o amortecedor viscoso convencional por um amortecedor do tipo eletromecânico. O amortecedor eletromecânico é formado por um transdutor de imã permanente e bobina móvel, no qual se acopla ao sistema mecânico com o eletromagnético. Nos terminais da bobina é introduzido um circuito elétrico RLC ligados em série. Para modelagem e a obtenção das equações dinâmica que descrevem seu movimento utilizou-se o método de Lagrange, que utiliza expressões de energia. Os modelos abordam absorvedores utilizados na indústria automobilística. No trabalho, primeiramente foi investigado a capacidade dos parâmetros elétricos no comportamento do sistema, e verificou-se a influência que a resistência elétrica e a capacitância tem em relação ao deslocamento da massa suspensa de um veículo. Foi realizada, através da função transferência, uma análise da quantidade de energia obtida no sistema elétrico para valores diferentes de resistência elétrica e em comparação foi verificado o ganho da massa suspensa para um movimento harmônico sofrido pela base. Por fim, investigou-se as potências geradas no circuito elétrico e o fator de potência para diferentes valores de capacitância. E também apurou a influência da resistência elétrica na produção de potência ativa. Os resultados mostraram a influência dos parâmetros elétricos no comportamento dinâmico do sistema e na geração de potência elétrica, assim através de um controle feito nesses parâmetros pode-se encontrar faixas no qual reduz a transmissibilidade de deslocamento para os ocupantes de um veículo e geram uma alta potência elétrica em que possa ser armazenada e utilizada posteriormente. / This work sought to investigate the dynamic behavior of an electromechanical suspension. For the configuration of this suspension it replaces the conventional viscous damper with a shock absorber of the electromechanical type. The electromechanical damper is formed by a permanent magnet transducer and mobile coil, in which it couples the mechanical system with the electromagnetic. At the terminals of the coil is introduced an RLC electric circuit connected in series. For the modeling and the obtaining of the dynamic equations that describe its movement was uses the Lagrange method, that uses expressions of conservation of energy. The models approach in a simplified way the absorbers used in the automotive industry. In the work, it was first investigated the influence of the electrical parameters on the behavior of the system, it was verifies the power of the electrical resistance and the capacitance have in relation to the displacement of the suspended mass of a vehicle. It was performed, through the transfer function, an analysis of the amount of energy obtained in the electrical system is performed for different values of electrical resistance and in comparison it was verifies the gain of the suspended mass for a harmonic movement suffered by the base. Finally, we investigated the powers generated in the electric circuit and the power factor for different capacitance values. It also determined the influence of electrical resistance on the production of active power. The results showed the influence of the electrical parameters on the dynamic behavior of the system and the generation of electric power, so through a control made in these parameters can be found tracks in which reduces the transmissibility of displacement for the occupants of a vehicle and generate a high electrical power where it can be stored and used later.

A particulate suspension under shear is a classic example of a system driven out of equilibrium. While it is possible to predict the equilibrium phase behaviour of a quiescent suspension, linking microscopic details to bulk properties under flow remains an open challenge. Our current understanding of sheared suspensions is restricted to two disparate regimes, the colloidal regime, for particle sizes d < 1 μm and the granular regime, for d > 50 μm. The physics of the industrially-relevant intermediate size regime, 1 μm ≲ d ≲ 50 μm, is unclear and has not been explored previously. In this thesis, we use conventional rheometry on a range of model spheres to develop the foundations of a predictive understanding of suspension flow across the entire size spectrum. In the first part of the thesis, we show that in repulsive particulate systems the rheology is characterised by two viscosity "branches" diverging at different volume fractions φRCP and φm, which represent states of flow with lubricated (frictionless) and frictional interactions between particles. In the intermediate size regime, there is a transition between these two branches above a critical onset stress σ* which manifests as shear thickening. This σ* is related to a barrier (invariably due to the charge or steric stabilisation) keeping particle surfaces apart. Our data are quantitatively fit by the Wyart and Cates theory for frictional thickening [1] if we assume that probability distribution of forces in the system is similar to in dry granular media. The onset stress for shear thickening is found to decrease with the inverse square of the particle size σ* / d ̄ 2 for diverse systems. We show that it is the competition between the scaling of σ*(d) and the size dependence of the entropic stress scale (~ d ̄ 3) that controls the crossover from colloidal to granular rheology with increasing size. Granular systems are "always shear thickened" under typical experimental conditions, while colloidal systems are always in a frictionless state. In the second part of the thesis, we explore the validity of the frictional framework for shear thickening. Although it quantitatively predicts our steady-state rheology, the frictional framework contradicts traditional fluid-mechanical thinking and has yet to be rigorously tested experimentally. In fact, there is a large body of literature that attributes thickening to purely hydrodynamic effects. Using dimensional analysis and simple physical arguments we examine possible physical origins for thickening and show that previously-proposed mechanisms can be subdivided into three types: two-particle hydrodynamic thickening, many-particle hydrodynamic thickening ("hydroclusters") and frictional-contact driven thickening. Many of these mechanisms can are inconsistent with the experimental two-branch phenomenology and can be disregarded. We further narrow down possible causes of thickening using the technique of flow reversal, which disentangles the relative contributions of contact and hydrodynamic forces to the viscosity. Consistent with recent simulations [2] and theory [1], we find that in each case thickening is dominated by the formation of frictional contacts and that hydrodynamic thickening, if present, is subdominant.

Este trabalho analisa minha produção em desenho entre 2013 e 2015; tratando-se da observação, descrição e problematização do meu processo de criação e do levantamento de ideias e ações decorrentes de todo esse processo. O desenho, como prática artística autônoma e autorreferente, é investigado a partir de uma relação de suspensão através da transferência de imagens fotográficas de referência, procurando estabelecer possíveis correlações entre a imagem produzida e a imagem sendo produzida. Este trabalho apresenta-se, pois, como um diálogo entre as camadas do processo de criação e suas reverberações conceituais e poéticas acerca da imagem. / This paper analyses my production in drawing between 2013 and 2015; dealing with the observation, description and questioning of my creation process and the lifting of ideas and actions resulting from this hole process. The drawing, as an autonomous and self-referential art practice, is investigated from a relation of suspension through the transfer of photographical images of reference, seeking to establish potential correlations between the produced image and the image being produced. This work presents itself, therefore, as a dialogue between the creative process layers and their conceptual and poetic reverberations about the image.

This work describes the modeling, control design, and experimental verification of an electromagnetic suspension system with position feedback using infrared sensors. A nonlinear model is obtained by fitting a first principle analytical model of the system to experimental data. A sliding control strategy is designed using a sliding surface derived from the model to achieve robust stabilization for the closed-loop system. The control is then implemented on an embedded commercial DSP system for experimental verification of the designed control on a laboratory scale electromagnetic suspension system. To compensate for the steady-state tracking error, two modifications are considered. In the first method, a small magnitude integral term is added to the error feedback, equivalently adjusting the reference signal and eliminating the constant bias. In the second method, an integral sliding control is considered, using a higher-order sliding surface, which also eliminates the constant bias. The experimental results show the efficacy of all designed control techniques. The modified techniques, unlike the original design, effectively eliminate the constant position error.