Neste trabalho realizamos cálculos teóricos das razões de povoamento dos níveis de estrutura fina do C0, C+ e Si+ considerando em detalhes os efeitos dos diversos mecanismos de excitação: colisões, fluorescência e a radiação cósmica de fundo. Empregamos dados atômicos recentes coletados na literatura na resolução das equações de equilíbrio estatístico pertinentes. A confrontação das razões de povoamento calculadas com as razões de densidades de coluna observadas disponíveis na literatura nos permite obter informações acerca das condições físicas (densidades volumétricas, intensidade de um campo de radiação UV presente, temperatura da radiação cósmica de fundo) e propriedades (dimensão característica e massa) dos sistemas damped Lyman a e Lyman Limit vistos em absorção no espectro de QSOs. Como um aparte, e por sua relação com o tema do trabalho, também investigamos a lei de temperatura da radiação cósmica de fundo. / In this work we perform theoretical calculations of the population ratios of fine structure levels of C0, C+ and Si+ considering in detail the effect of the various excitation mechanisms: collisions, fluorescence and the cosmic background radiation. We employ recent atomic data, gathered in the literature, to solve the related statistical equilibrium equations. The comparison of the calculated population ratios with the observed column densities ratios available in the literature allows us to obtain informations regarding the physical conditions (volume densities, intensity of a UV radiation field present, temperature of the cosmic background radiation) and properties (characteristic size and mass) of damped Lyman a and Lyman Limit systems seen in absorption in spectra of QSOs. We also investigate the temperature law of the cosmic background radiation, which bears a tight relationship with this work.

A dinâmica do mundo moderno em que a competitividade é a palavra de ordem tem forçado as organizações a se estruturarem no sentido de elaborar Planos Estratégicos de Tecnologia que contemplem a criação de projetos de pesquisa e inovação no curto, médio e longo prazos. Nesse contexto, cabe ao Gestor de Tecnologia administrar e alocar os recursos financeiros limitados da organização em iniciativas que proporcionem oportunidades de introduzir no mercado inovações que agreguem valor seja em termos financeiros, seja para a sustentabilidade e imagem da empresa. No passado, os Planos Estratégicos de Tecnologia baseados na experiência e na intuição dos Gestores de Tecnologia e da Alta Administração das empresas produziram bons resultados, porém em mercados dinâmicos e interconectados globalmente não há margem para erros, sob pena de comprometer a continuidade do negócio. Faz-se necessário utilizar metodologias que permitam ao Gestor de Tecnologia ponderar os riscos e as possibilidades de sucesso na implementação de programas de Inovação Tecnológica e foi essa reflexão que impeliu este autor a estabelecer os seguintes objetivos para este projeto de pesquisa: a) Identificar e aplicar uma metodologia de análise e prospecção tecnológica utilizando um conjunto de ferramentas tais como Análise Morfológica, Método Delphi, Matrizes de Decisão e \'Technological Roadmapping\' que permitam a elaboração de um Mapa Tecnológico (roadmap) aplicado a um escopo tecnológico específico e que também sirvam como um roteiro de trabalho para outros ramos da tecnologia; b) Apresentar ao leitor as lições aprendidas (acertos e erros) no processo de pesquisa bem como recomendações para o uso dessas técnicas e sugestões para estudos futuros. Escolheu-se como tema desta pesquisa-ação um produto específico da empresa Magneti Marelli Cofap, na qual o autor deste trabalho exerce a função de Gestor de Inovação, a saber, o Amortecedor Estrutural. A composição das Metodologias acima gerou um rico acervo de dados que, com a aplicação da metodologia implementada, gerou um roadmap tecnológico para redução de peso no amortecedor estrutural. Apresentaram-se também os acertos e erros observados no processo de pesquisa, bem como sugestões de melhoria para estudos futuros, que se constitui de material com grande valor acadêmico e gerencial, uma vez que a metodologia desenvolvida pode ser aplicada integral ou parcialmente em qualquer campo da tecnologia. / Modern world dynamics in which competitivity is the key word has forced organizations to structure themselves in a way to elaborate Strategic Technology Plans which consider the creation of research and innovation projects in short, medium and long terms. In this context it is up to Technology Manager to administrate and allocate the organization\'s limited financial resources in initiatives which enable opportunities to introduce innovations in the market which could add value either in financial terms and or for sustainability and Company\'s image. In the past Technology Strategic Plans which were based on Innovation Managers and Top Administration experience and intuition have produced good results, but in dynamic and globally interconnected markets there is no margin for mistakes under the penalty to compromise business continuity. There is a need to use Methodologies which enable the Technology Manager to balance the risks and success possibilities when implementing Technology Innovation programs and this reflection impelled the author to establish the following objectives for this research: a) Identify and apply Technological and Forecast analysis methodologies using a range of tools like Morphological Analysis, Delphi Method, Decision Matrix and Technological Road mapping which could allow the elaboration of Technological Roadmap applied to a specific technological scope and that could serve as well as a work routine for other technology branches.; b) Show to the reader the lessons learned in this research\'s process (right points and mistakes) as well as recommendations for this techniques use and suggestions for future studies. A specific product from Magneti Marelli in which this research\'s author works as Innovation Manager has been chosen as a theme for this action researches, that is, the Strut. The abovementioned methodologies composition has generated a rich data bank. The methodology implementation over these data generated a Technological Roadmap aiming to reduce weight in Struts. The right points and mistakes observed during research process have been shown as well suggestions for future studies. This is considered a material with a great academic and managerial value since the developed methodology can be applied total or partially in any technology field.

Submitted by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-01-25T12:14:18Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Amortecedor dinâmico viscoelástico com memória para vibrações de um edifício de pequeno porte.pdf: 11017464 bytes, checksum: e73bee380f594a2a6d4d26265fc6eb1b (MD5) / Approved for entry into archive by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-01-25T12:16:51Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Amortecedor dinâmico viscoelástico com memória para vibrações de um edifício de pequeno porte.pdf: 11017464 bytes, checksum: e73bee380f594a2a6d4d26265fc6eb1b (MD5) / Made available in DSpace on 2017-01-25T12:16:51Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Amortecedor dinâmico viscoelástico com memória para vibrações de um edifício de pequeno porte.pdf: 11017464 bytes, checksum: e73bee380f594a2a6d4d26265fc6eb1b (MD5) Previous issue date: 2013-09-06 / Neste trabalho, apresenta-se a análise numérica da eficiência de um amortecedor dinâmico de material viscoelástico com memória (ADVM) para aplicação na redução dos estados de ressonância de edifícios de pequeno porte, modelados por pórticos planos, submetidos a excitações dinâmicas de um motor elétrico com fonte de energia limitada e de velocidade angular variável (SNI – Sistema Não Ideal). Elabora-se um modelo matemático do sistema completo com quatro graus de liberdade: dois relacionados com o deslocamento horizontal e angular do pórtico plano e do motor e dois relacionados com o material ADVM. Ensaios computacionais foram realizados utilizando-se o MATLAB® em base do algoritmo de Runge-Kutta com passo adaptativo. Analises do comportamento do sistema com e sem controle foram realizadas através das ferramentas da dinâmica não linear, entre eles: planos de fase, as séries temporais, FFT e curvas de ressonância. / In this paper, we present the numerical analysis of the efficiency of a dynamic damper with memory viscoelastic material (VEMD) for application in the reduction of resonance states of small buildings, Modeled by plane frames subjected to dynamic excitations of an electric motor with limited power source and variable angular velocity (SNI – Non-Ideal System). Draws up a mathematical model of the complete system with four degrees of freedom: two related horizontal displacement and angular gantry plane and engine related to the two materials ADVM. Computational tests were performed using MATLAB ® based on the Runge-Kutta algorithm with adaptive step. The Analysis of the system behavior with and without control was performed using the tools of nonlinear dynamics, including: phase plane, time series, FFT and resonance curves.

An experimental investigation of heat and mass transfer in a horizontal tube falling-film ammonia-water absorber was conducted. A tube bank consisting of four columns of six 9.5 mm (3/8 ) nominal OD, 0.292 m (11.5 ) long tubes was installed in an absorber shell that allowed heat and mass transfer measurements and optical access. A test facility consisting of all the components of a functional absorption chiller was fabricated specifically for this investigation. Several variations of the basic system set up were fabricated to enable testing over the wide range of conditions (nominally, desorber solution outlet concentrations of 5 - 40% for three nominal absorber pressures of 150, 345 and 500 kPa, over solution flow rates of 0.019 0.034 kg/s.) Measurements at the absorber were used to determine heat transfer rates, overall thermal conductances, solution-side heat and vapor-side mass transfer coefficients for each test condition. For the range of experiments conducted, the solution heat transfer coefficient varied from 923 to 2857 W/m2-K while the vapor mass transfer coefficient varied from 0.0026 to 0.25 m/s and the liquid mass transfer coefficient varied from 5.51×10-6 to 3.31×10-5 m/s depending on the test condition. The solution heat transfer coefficient increased with increasing solution flow rate; however, the vapor and liquid mass transfer coefficients seem to remain unaffected with the variations in solution flow rate and were found to be primarily determined by the vapor and solution properties. The experimental heat and mass transfer coefficients were compared with the relevant studies from the literature. Based on the observed trends, heat transfer correlations and mass transfer correlations in the vapor and liquid phases were developed to predict heat and mass transfer coefficients for the range of experimental conditions tested. These correlations can be used to design horizontal tube falling-film absorbers for ammonia-water absorption systems.

Modern battle tanks are equipped with gun stabilization systems using gyro and encoder data to stabilize the gun barrel, although these systems are very sensitive and reliable, these systems assume the gun barrel as a rigid beam, and do not use information from

A comprehensive set of experimental and numerical comparisons of the performance of two self-reacting point absorber wave energy converter (WEC) designs is undertaken in typical operating conditions. The designs are either currently, or have recently been, under development for commercialization. The experiments consist of a series of 1:25 scale model tests to quantify hydrodynamic parameters, motion dynamics, and power conversion. Each WEC is given a uniquely optimized power take off damping level. For hydrodynamic parameter identification, an optimization based method to simultaneously extract Morison drag and Coulomb friction coefficients from decay tests of under-damped, floating bodies is developed. The physical model features a re-configurable reacting body shape, a feedback controlled power take-off, a heave motion constraint system, and a mooring apparatus. A theoretical upper bound on power conversion for single body WECs, called Budal's upper bound, is extended to two body WECs. The numerical analyses are done in three phases. In the first phase, the WECs are constrained to heave motion and subjected to monochromatic waves. Quantitative comparisons are made of the WEC designs in terms of heave motion dynamics and power conversion with reference to theoretical upper bounds. Design implications of a reactive power take-off control scheme and relative motion constraints on the wave energy converters are investigated using an experimentally validated, frequency domain, numerical dynamics model. In the second phase, the WECs are constrained to heave motion and subjected to panchromatic waves. A time domain numerical model, validated by the experimental results, is used to compare the WECs in terms of power matrices, capture width matrices, and mean annual energy production. Results indicate that the second WEC design can convert 30% more energy, on average, than the first design given the conditions at a representative location near the West coast of Vancouver Island, British Columbia, Canada. In the last phase, the WECs are held with three legged, horizontal, moorings and subjected to monochromatic waves. Numerical simulations using panelized body geometries for calculations of Froude-Krylov, Morison drag, and hydrostatic loads are developed in ProteusDS. The simulation results---mechanical power, mooring forces, and dynamic motions---are compared to model test results. The moored WEC designs exhibit power conversion consistent with heave motion constrained results in some wave conditions. However, large pitch and roll motions severely degrade the power conversion of each WEC at wave frequencies equal to twice the pitch natural frequency. Using simulations, vertical stabilizing strakes, attached to the reacting bodies of the WECs are shown to increase the average power conversion up to 190% compared to the average power conversion of the WECs without strakes. / Graduate / scottb@uvic.ca

Series impedances, including source and transfer impedances, are commonly used to model a variety of noise sources and noise treatment elements in duct systems. Particle velocity is assumed to be constant on the plane where the series impedances are defined. The research reported herein details investigations into measuring source and transfer impedance. Especially, the measurement and prediction of the transfer impedance of micro-perforated panel (MPP) absorbers is considered. A wave decomposition method for measuring source impedance and source strength was developed that was purely based on acoustic concepts instead of the equivalent circuit analysis. The method developed is a two-load method. However, it is not necessary to know the impedances of either load a priori. The selection of proper loads was investigated via an error analysis, and the results suggested that it was best to choose one resistive and one reactive load. In addition, a novel type of perforated element was investigated. MPP absorbers are metal or plastic panels with sub-millimeter size holes or slits. In the past, Maa's equation has been used to characterize their performance. However, Maa's equation is only valid for circular perforations. In this research, an inverse method using a nonlinear least square data fitting algorithm was developed to estimate effective parameters that could be used in Maa's theory. This inverse approach was also used to aid in understanding the effect of dust and fluid contamination on the performance of MPP absorbers. In addition, an approach to enhance the attenuation of MPP absorbers by partitioning the backing cavity was investigated experimentally and numerically. Results indicated that partitioning improved the attenuating of grazing sound waves. The effect of modifying both the source and transfer impedances on the system response was also studied using the Moebius transformation. It was demonstrated that the Moebius transformation is a mathematical tool that can be employed to aid in determining and understanding the impact of acoustic impedance modifications on a vibro-acoustic system.

A study of thermal, structural, electrical and optical characteristics of molybdenum black surface coatings on various substrates has been made. The suitability of these coatings for use as selective absorbers for solar collector applications has been assessed. Molybdenum black (Mo black) coatings were prepared by electrodeposition (on aluminium) and a chemcial conversion method (on zinc and electroplated cobalt on nickel plated copper substrates). The solar absorptancer (αs) and thermal emittances (εth) of the coatings were determined from room temperature spectral reflectance measurements in the solar (0.3 to 2.5μm) and infrared regions (2.5 to 50 μm) respectively. The effect of different preparation parameters and substrate pretreatments on the spectral selectivity has been investigated in order to optimize the thermal performance. The spectral selectivity is related to the Mo-black coating thickness and surface roughness together with the microstructure, of the substrate and the intermediate layer. Dip coatings on polished zinc have significant selectivity (αs/ εth = 8.4 when αs = 0.76). The absorptance of the dip coatings is increased to 0.87 with εth = 0.13 by chemical etching of zinc prior to coating deposition. For coatings on electroplated cobalt on nickel plated copper (cobalt (NC) substrate), an absorptance as high as 0.94 has been obtained with an emittance value 0.3. By using an addition agent in the plating solution of cobalt the high emittance can be reduced to 0.1 with αs = 0.91 giving a coating with a relatively high efficiency (82.5%) for photo-thermal energy conversion. A study of the surface composition and microstructure of the coatings has been made using scanning and transmission electron microscopy together with electron diffraction, X-ray diffraction and X-ray photoelectron spectroscopy. The structural investigations indicate that Mo-black coatings contain polycrystals of orthorhombic Mo4O11 with a small proportion of Ni(OH)2. Presence of water and also Mo4O11 in the coatings are evident from IR spectroscopy study. The bandgap of the coating has been determined from optical transmission spectra (1.66 eV) and also from reflectance spectra (0.85 eV). The discrepancy between these two values has been discussed. The refractive indices of the coatings have also been estimated. The band gaps and refractive indices are found to be related to the spectral selectivity of the coatings. The durability test of the coatings shows that the coatings on etched zinc are more resistant to heat treatment than the coatings on unetched zinc. The coatings on cobalt (NC) substrates also show good stability for relatively short periods at temperatures ~400ºC. A study of the electrical properties of Mo-black coatings suggests that at electrical field strengths (greater than 106v/m the dominant conduction process is of the Poole-Frenkel type. The activation energy of the conduction process has been estimated to be -0.56 eV at higher temperatures. The effect of heat treatment on the electrical properties of the coatings has been examined. The dielectric constant of Mo-black has been estimated from A. C. measurements. At high frequency (20 kHz) the value of the dielectric constant is about 4.0.

Broadband, variable, and random excitations are often suppressed using active vibration absorbers (AVAs). While AVAs can be effective, they also are expensive and subject to instability when the disturbance is ill defined. A state-switched absorber (SSA) can be used for these same vibration classes while reducing the expense and instability because an SSA is only allowed to be active at discrete instances. SSAs are spring-mass-damper devices in which at least one element is controllably variable. The work presented in this dissertation evaluates the properties of magnetorheological elastomers (MREs) to assess their use in SSAs as variable springs. MREs are elastomers doped with magnetically permeable material, generally iron. They are modeled as lossy springs, and have stiffness and loss factor components. Natural frequency and stiffness behavior, and their relationships to static displacement, iron content, and forcing frequency and amplitude were determined. Loss factors were found to be independent of MRE content, configuration, and static displacement. This was confirmation that MREs are in fact controllable springs. Natural frequencies changed in the presence of magnetic fields by as much as 360%. The corresponding change in static displacement could not account for this frequency change. Transient data was found by determining the length of time it took for an MRE to achieve quasi-steady state oscillation behavior when subjected to a harmonic excitation. This time was referred to as the characteristic response time. The characteristic response time correlated to the ratio of the forcing frequency to the zero-field natural frequency. When a magnetic field was turned on, the characteristic response time on average was found to be consistently longer than when the magnetic field was turned off, regardless of iron content or configuration. The difference between these two characteristic response times is caused by the particles' mechanics. To form a chain, a magnetic field must both be set up, and particles must move to join together. When a chain is broken, the magnetic field must merely be removed. However, this difference gives opportunities for future research to be conducted on controlling MREs' transient responses.

Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-01-23Bitstream added on 2014-06-13T18:57:52Z : No. of bitstreams: 1 iossaqui_jg_me_bauru.pdf: 959981 bytes, checksum: c19d1d4dc04cd2fd6c835a084363d5d8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho investigou-se a efetividade de um absorvedor de vibrações eletromecânico linear e um absorvedor de vibrações eletromecânico não-linear na atenuação de vibrações em estruturas não-ideais. Dois modelos não-lineares foram utilizados para representar o sistema estudado, uma viga engastada excitada por uma fonte não-ideal. Um modelo simplificado que considera o torque gerado pelo motor como sendo uma função linear e um modelo mais completo que considera as propriedades elétricas do motor CC. As equações que governam a dinâmica do sistema foram deduzidas pelas equações de Lagrange, parte mecânica, e pelas leis de Kirchhoff, parte elétrica. Simulações numéricas dos dois modelos foram realizadas no módulo Simulink® do software MATLAB®. Uma análise do efeito dos parâmetros não-lineares no sistema foi realizada. Resultados mostram a redução do salto nas curvas de resposta-frequência - efeito Sommerfeld - fenômeno típico de sistemas não-ideais. O estudo da estabilidade foi realizado conforme a análise de estabilidade de Lyapunov. Uma solução analítica aproximada, para o movimento estacionário do sistema, foi obtida através de um método de perturbação (método da média). Para completar o estudo, analisou-se a interação dinâmica dos absorvedores de vibrações eletromecânicos em outros modelos de sistemas não-ideais que apresentam comportamentos caóticos. Os resultados obtidos mostram a supressão de caos, através da transformação de movimentos caóticos em movimentos periódicos. / In this work, we investigated the effectiveness of a linear electro-mechanical vibration absorber and a nonlinear electro-mechanical vibration absorber that is used for the vibration attenuation in a non-deal structure. Two nonlinear models were used to represent a cantilever beam supporting a nonideal energy source at its free end. The first model simplified takes into account the stationary characteristics of the energy source and the second model takes into account also influence of the dynamics of the oscillating mechanical elements on electrical properties of the DC motor. The governing equations of the models are deduced by Lagrange's equations and also by Kirchhoff's laws. The numerical simulations of models were implemented using the Simulink® module of Matlab® software. A numerical analysis of the effects of the parameters of nonlinearity was presented. Others results whowed the reduction of the Sommerfeld effect. We analytically determine the expression for the steady-state solutions using the method of averaging. We also analyzed the dynamic interaction between the electromechanical vibration absorber and the others nonideal structural that have chaotic behavior. We have found that the chaotic motion of the main system has been transformed to periodic motion, see as a quenching of chaotic vibrations.