Submitted by PPG Engenharia El?trica (engenharia.pg.eletrica@pucrs.br) on 2018-10-16T14:38:56Z No. of bitstreams: 1 ANA PAULA RODRIGUES MARQUES_DIS.pdf: 2882882 bytes, checksum: a47b86d791e0aae8d3266c6fc3b8a61b (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-10-18T11:08:37Z (GMT) No. of bitstreams: 1 ANA PAULA RODRIGUES MARQUES_DIS.pdf: 2882882 bytes, checksum: a47b86d791e0aae8d3266c6fc3b8a61b (MD5) / Made available in DSpace on 2018-10-18T11:15:22Z (GMT). No. of bitstreams: 1 ANA PAULA RODRIGUES MARQUES_DIS.pdf: 2882882 bytes, checksum: a47b86d791e0aae8d3266c6fc3b8a61b (MD5) Previous issue date: 2017-05-31 / There has been a recent increase in the use of new technologies playing an important role in promoting physical fitness, due to the positive impact they have on the health and quality of life of the individual. Taking this into consideration, the present work describes the development of a vibration platform linked to a flywheel (PV?I), which permits whole-body vibration (WBV) and resistance or isoinertial training. Correct measurement of the force values given by the flywheel and amplitude, frequency and acceleration ranges provided by the vibration platform was necessary for production of the prototype. The need to adapt various pieces of equipment and materials was also identified, such as the vibrator motor, springs, vibration dampers, roller bearings, axis, flywheel and frequency inverter. The equipment was validated through laboratory testing, aimed at verifying the performance of the PV?I. A comparator clock was used to measure amplitude, and a triaxial accelerometer provided the platform acceleration data. A frequency inverter was used to regulate the platform frequency. The vibration platform frequencies chosen for the prototype operation evaluation tests were 5Hz to 60Hz, with no platform load, the vibrator motor set at minimum intensity, with acceleration on all three axes (x, y and z) and amplitude measured every 5Hz. Tests were subsequently performed with a 52kg load, simulating the weight of a person, and the vibrator motor set at a vibration intensity of 10% and 20%. Both the platform displacement amplitude and acceleration measurements were acquired at 15Hz, 20Hz, 25Hz, 30Hz and 35Hz, and acceleration alone was also recorded at 40 Hz and 45 Hz. Two further tests were performed with a 55kg load and vibrator motor set at 30% and 40% intensity. These choices were based on findings in the literature, where the most encountered frequency ranges varied between 15Hz and 44Hz. The results demonstrate a relationship between frequency and amplitude; when one is altered the other also changes. The acceleration values collected during testing were used to analyze the vibration levels, in accordance with the ISO 2631-1 (1997) standard. The vibration levels of the platform, in the test configurations used, were confirmed as being acceptable. / O uso de novas tecnologias, que desempenham um papel importante em promover o condicionamento f?sico, tem se intensificado recentemente pelo impacto positivo que causam na qualidade de vida e na sa?de das pessoas. Com base nisso, o presente trabalho descreve o desenvolvimento de uma plataforma vibrat?ria associada a um volante de in?rcia (PV?I), os quais permitem treinamento de vibra??o de corpo inteiro (TVCI) e resistido ou isoinercial. Para a confec??o do prot?tipo, foi necess?rio o correto dimensionamento dos equipamentos, a partir dos valores de for?a oferecidos pelo volante de in?rcia e da faixa de amplitude, da frequ?ncia e da acelera??o fornecidas pela plataforma vibrat?ria. Foi tamb?m identificada a necessidade de adapta??o de diversos equipamentos e materiais, tais como motovibrador, molas, amortecedores de vibra??o, mancais de rolamento, eixo, volante de in?rcia e inversor de frequ?ncia. Para a valida??o do equipamento, foram realizados testes em laborat?rio, com o objetivo de verificar o funcionamento da PV?I. A medi??o de amplitude foi feita por um rel?gio comparador, enquanto os dados da acelera??o da plataforma foram adquiridos com o uso de um aceler?metro triaxial. A frequ?ncia aplicada ? plataforma foi regulada atrav?s de um inversor de frequ?ncia. As frequ?ncias da plataforma vibrat?ria escolhidas foram de 5Hz a 60Hz nos testes de avalia??o do funcionamento do prot?tipo sem qualquer carga sobre a plataforma e com o motovibrador em intensidade m?nima, sendo a acelera??o nos tr?s eixos (x, y e z) e a amplitude medidas a cada 5Hz. Ap?s, foram realizados testes com carga de 52kg, simulando a massa de uma pessoa, e o motovibrador regulado a uma intensidade de vibra??o de 10% e 20%. As amplitudes de deslocamento da plataforma foram adquiridas em 15Hz, 20Hz, 25Hz, 30Hz e 35 Hz, enquanto a medida da acelera??o incluiu tamb?m 40 Hz e 45Hz. Outros dois ensaios foram feitos com carga de 55kg e o motovibrador regulado a 30% e 40%. Tais escolhas foram feitas com base na literatura onde a faixa de frequ?ncia mais encontrada variam entre 15Hz e 44Hz. Os resultados demonstraram que h? uma rela??o entre frequ?ncia e a amplitude, pois quando se altera a frequ?ncia, a amplitude tamb?m se modifica. As acelera??es coletadas durante os testes serviram para fazer a an?lise dos n?veis de vibra??o, tendo como base a norma ISO 2631- 1 (1997), comprovando que s?o aceit?veis os n?veis de vibra??o da plataforma nas configura??es utilizadas nos testes.

Direct reading instruments (DRIs) are popular devices for measuring aerosols because they provide rapid on-site measurement of particle size and/or concentration. However, the output of DRIs may drift over time requiring frequent manufacturer calibration. Given the possibility of drift, the output of DRIs should ideally be verified to ensure proper response before and after field use. Methods for verifying the output of DRIs particle size reading are available for use in laboratory and field. However, methods for verifying the DRIs concentration reading are complex and often use of stationary installations that are not suited for field work. The objective of this study was to develop a verification device that can be used in the field to verify the output of DRIs for measuring aerosol concentration. The new device uses a nebulizer that produces aerosols through vibrating mesh technology. This vibrating mesh nebulizer (VMN) uses only electrical input to generate aerosols and does not require compressed air. The verification device was able to produce stable output of aerosols at low concentrations (0.2 mg/m3 to 1.2 mg/m3). It was also possible to produce different concentration levels of aerosol by changing the electrical current to the VMN. The verification device was used to monitor and validate the output of a condensation particle counter and a photometer. Results showed that both instruments having valid output and did not require manufacture calibration. The verification device made it possible to monitor and verify the output of two DRIs. This was achieved by generating reproducible aerosol output with specific composition. This verification device presents a practical method to verify the concentration output of DRIs for measuring aerosols.

This dissertation addresses rigid body attitude control with piecewise sinusoidal signals. We consider rigid-body attitude kinematics on SO(3) with a class of sinusoidal inputs. We present a new closed-form solution of the rotation matrix kinematics. The solution is analyzed and used to prove controllability. We then present kinematic-level orientation-feedback controllers for setpoint tracking and command following. Next, we extend the sinusoidal kinematic-level control to the dynamic level. As a representative dynamic system, we consider a CubeSat with vibrating momentum actuators that are driven by small $\epsilon$-amplitude piecewise sinusoidal internal torques. The CubeSat kinetics are derived using Newton-Euler's equations of motion. We assume there is no external forcing and the system conserves zero angular momentum. A second-order approximation of the CubeSat rotational motion on SO(3) is derived and used to derive a setpoint tracking controller that yields order O(ε2) closed-loop error. Numerical simulations are presented to demonstrate the performance of the controls. We also examine the effect of the external damping on the CubeSat kinetics. In addition, we investigate the feasibility of the piecewise sinusoidal control techniques using an experimental CubeSat system. We present the design of the CubeSat mechanical system, the control system hardware, and the attitude control software. Then, we present and discuss the experiment results of yaw motion control. Furthermore, we experimentally validate the analysis of the external damping effect on the CubeSat kinetics.

Oil analysis is a broad field comprised of hundreds of individual tests that provide meaningful benefit by assessing one or more properties of lubricants or machines. Many tests are performed on new types of oil during research and development. The lubricants chemical, physical, or lubricating properties are validated for quality control purposes and product performance classification. Much of the research in this area is devoted to the online oil degradation systems which allow getting a prompt response about the condition of lubricant. This thesis investigates the concept for monitoring oil degradation with a vibrating Kelvin probe technique. The Vibrating Kelvin probe method for measuring the work function of metals has been used since 1932. Among the applications of this technique are adsorption, corrosion, friction and other studies. A novel application of this method is proposed in this thesis. The vibrating Kelvin system was created with one static surface acting as a sampling surface and the other one electrically isolated. The interaction of the oil with one of the surfaces of a capacitor results in a signal which is synchronously measured. The oil molecules adsorb on the surface of one of the plates and form a space charge layer which changes the work function of that surface. Oil prepared by intentional oxidation was used to evaluate and to monitor the ability to see changes in oil.

No description available.

Enhanced heat transfer in electronic hardware by direct, small-scale actuation is investigated experimentally in two test bed configurations. The first configuration exploits the unsteady motions induced by a vibrating reed embedded within a heated duct (in contact with hardware that needs cooling) to enhance forced convection transport heat from the duct surfaces. The flow within the duct is either exclusively driven by the reed or, for higher heat flux, is augmented by an induced core flow. The time harmonic motion of the reed results in the regular shedding of vortical structures that interact with the inner surfaces in the absence and presence of a core flow. The second configuration focuses on the effects of small scale motions induced by a synthetic jet on heat transfer within an advanced heat sink. The synthetic jets emanate directly through the base of the heat sink and induce a recirculating flow between the fins, resulting in a lower thermal resistance than what is typically achieved with traditional fans. The unsteady flow characteristics in both configurations are investigated using particle image velocimetry (PIV). Of particular interest are the effects of small-scale motions and enhanced mixing on heat transfer compared to conventional time-invariant flows at similar or higher Reynolds numbers.

Mechanical systems under vibration excitation are prime candidate for being modeled by linear time invariant systems. Damage localization using both finite element information and modal parameters estimated from ambient vibration data collected from sensors is possible by the Stochastic Dynamic Damage Location Vector (SDDLV) approach, where the damage location is empirically related to positions where the stress is close to zero. The first contribution in this thesis shows how the uncertainty in the estimates of the state space system can be used to derive uncertainty bounds on the damage localization residuals to decide about the damage location with a hypothesis test using one chosen Laplace value. In the second contribution, the damage localization method is extended with a statistical framework and robustness of the localization information is achieved by aggregating results at different values in the Laplace domain. The Influence Line Damage Location (ILDL) is a complementary approach of the SDDLV where the subspace angle is computed and damage is empirically located at points near zero. The last contribution describes how robustness of the localization information is achieved by aggregating results at different values in the Laplace domain based on the previous two contributions. The proposed methods are validated and successfully applied to damage localization of several applications in civil structures.

O zinco vem sendo utilizado, já há bastante tempo, como revestimento protetor e decorativo para peças metálicas [1]. No entanto, cada vez mais a indústria busca revestimentos protetores que sejam mais resistentes à corrosão, que tenham boas características de soldabilidade, pintabilidade e, principalmente baixo custo. Os métodos mais comuns pelos quais os revestimentos de zinco são aplicados são imersão a quente, eletrodeposição e aspersão térmica. O presente trabalho tem como objetivo caracterizar a morfologia dos revestimentos Galvanized (GI), Galvannealed (GA) e Zn-55Al de zinco obtidos pelo processo de imersão a quente, verificar o comportamento eletroquímico e analisar o comportamento corrosivo dos revestimentos pelas técnicas de Potenciometria e Eletrodo Vibratório (SVET). Os resultados demonstraram que é possível a análise das fases por voltametria em microcélula no revestimento em que as fases foram crescidas, porém, não é possível aplicar a técnica nas diferentes fases formadas nos revestimentos industriais devido à espessura dos revestimentos. Não foi observado influência da luz Ultravioleta-visível na taxa de corrosão dos revestimentos estudados por SVET e esta técnica mostrou-se satisfatória para grandes aumentos e pequenas áreas. As análises por SVET demonstraram a possibilidade de analisar a corrosão localizada em diferentes fases intermetálicas nos revestimentos. / Zinc has been used for quite some time, as decorative and protective coating for metal parts. However, the industry increasingly seeks protective coatings that are more resistant to corrosion, have good weldability characteristics, and especially low cost. The most common methods by which zinc coatings are applied are hot dipping, electroplating and thermal spraying. The present work aims to characterize the morphology of the coatings Galvanized (GI), galvannealed (GA) and Zn-55Al of zinc obtained by hot dip process, check the electrochemical behavior and analyze the behavior of coatings for corrosion techniques of pots and Vibrating electrode (SVET). The results showed that it is possible to analyze the phases by microcell voltammetry in the coating in which the phases were grown, however, is not possible to apply the technique in the different phases formed in industrial coatings due to the thickness of coatings. There was no influence of UV-VIS in the corrosion rate of the coatings studied by SVET and this technique was satisfactory for large and small areas increases. The analysis by SVET demonstrated the possibility of analyzing the localized corrosion in different intermetalic phases in coatings.

Este trabalho versa sobre desenvolver a habilidade de “reconhecer características ou propriedades de fenômenos ondulatórios ou oscilatórios, relacionando-os a seus usos em diferentes contextos” (BRASIL, 2009, p.8) de uma forma menos tradicional. O objetivo foi abordar o conteúdo de acústica utilizando instrumentos musicais (violão, guitarra, flauta, xilofone, lira...). A partir de ondas estacionárias em tubos sonoros e cordas vibrantes, foram elucidados os conceitos de altura, intensidade e timbre, relacionando com os conceitos básicos de ondas – frequência, comprimento de onda, amplitude, velocidade de propagação das ondas em cordas de diferentes densidades lineares, entre outros. Também foram trabalhadas notas musicais e conceitos bem básicos de formação de acordes. A proposta foi aplicada com os dois nonos anos de um colégio particular bastante tradicional de Novo Hamburgo: o Colégio Marista Pio XII. Nesta fase final do Ensino Fundamental, o colégio disponibiliza aos seus alunos cinco períodos de Ciências da Natureza, distribuídos em: um de Biologia, dois de Física e dois de Química. A ideia é que fossem trabalhadas Competências e Habilidades comuns aos componentes curriculares, por meio de sequências didáticas. O trabalho foi aplicado em um total de seis encontros, cada um com duração de 50 min. Alguns desses períodos foram dedicados a aulas puramente expositivas, outros deles com aulas expositivas dialogadas, com a utilização de uma espiral de caderno, uma guitarra, um cavaquinho, instrumentos de sopro e do computador, onde interpretamos as frequências fundamentais emitidas pela vibração das cordas e do ar em tubos sonoros com o software Spectrogram1. Como referencial teórico, utilizamos a teoria sócio-interacionista de Vygotsky e alguns conceitos de alfabetização científica. A discussão e o manuseio de instrumentos musicais em pequenos grupos fizeram com que os alunos interagissem entre si e com o professor, favorecendo a construção do conhecimento e a interação de signos. A partir dessas interações aluno - instrumentos musicais, professor - aluno e aluno – aluno, o objetivo era abrir espaço para questionamentos, discussões e reflexões, de maneira que o conhecimento fosse sintetizado por todos. Como referência para o planejamento de ensino, construção do significado das aulas e análise das interações, utilizamos uma ferramenta analítica de Mortimer e Scott (2002). / This work is about developing the ability to "recognize characteristics or properties of wave or oscillatory phenomena, relating them to their uses in different contexts "(BRASIL, 2009, p.8), in a less traditional way. The objective was to approach the content of acoustics using musical instruments (guitar, electric guitar, flute, xylophone, lyre ...). From stationary waves in sound tubes and vibrating strings, concepts of height, intensity and timbre, were elucidated, relating them to the basic concepts of waves - frequency, wavelength, amplitude, velocity of wave propagation in strings of different linear densities, among others. Musical notes and basic concepts of chord formation were also seen. The proposal was applied with two groups of nineth graders from a very traditional private school in Novo Hamburgo: Marista Pio XII school. In this final phase of elementary school, the school offers its students five classes of Science a week, distributed in one of Biology, two of Physics and two of Chemestry. The idea was work with common skills to these curricular components, through didactic sequences. The work was applied out in a total of six classes, each lasting 50 min. Some of these were devoted to purely expository presentation, others with dialogic lectures, with the use of the spiral of a notebook, a guitar, another small kind of guitar, wind instruments and a computer where we interpret the fundamental frequencies emitted by the vibration of the strings and air in sound tubes with the Spectrogram software2. As a theoretical reference, we use Vygotsky's socio-interactionist theory and some concepts of scientific literacy. The discussion and manipulation of musical instruments in small groups led the students to interact with each other and with the teacher, favoring the construction of knowledge and interaction. From these student - musical instruments, teacher - student and student – student interactions, the objective is to open space for questions, discussions and reflections, so that knowledge was synthesized by all. As a reference for teaching planning, construction of meaning and interaction analysis, l we used an analytical tool by Mortimer and Scott (2002).

Ce travail de thèse concerne l'étude de l'influence des ultrasons sur les transferts de chaleur. Il a été réalisé à partir de la conception d'un échangeur de chaleur dont la structure peut être mise en vibration à sa fréquence de résonance dans la gamme des ondes ultrasonores : 35 kHz. L'influence des ultrasons sur l'augmentation des transferts thermiques a ainsi pu être mise en évidence directement au sein du système. L'étude bibliographique a mis en avant l'originalité de ce travail, qui correspond à une première approche relative à un échangeur fluide-fluide. La conception de l'échangeur, du banc d'essais et du système d'acquisition dédiés a fait l'objet de la première partie de ce travail. Ensuite, la mise au point de méthodes pour l'analyse des performances énergétiques et leur implémentation ont constitué une deuxième partie. Enfin, des configurations opératoires variées (régimes d'écoulement, configurations hydrauliques, matériaux constitutifs, …) ont pu être étudiées. De plus, le potentiel des ultrasons quant à la réduction de l'encrassement au sein de l'échangeur a aussi été mis en évidence. / This work deals with the influence of ultrasound on heat transfer. It relies on the conception of a new kind of heat exchanger, whose structure can be set into vibration at its resonance frequency in the ultrasonic range : 35 kHz. The influence of ultrasound on heat transfer enhancement was thus directly observed within the system. The literature survey showed the originality of this work, corresponding to a first approach of a fluid-fluid heat exchanger. The conception of the heat exchanger, of the test rig and acquisition system both especially dedicated was the main object of the first part of this work. Then, the development of methods for the analysis of energetic performances and their implementation constituted the second part. Finally, various operating configurations (flow regimes, hydraulic configurations, constitutive materials, …) have been studied. Besides, the potential of ultrasound concerning fouling reduction inside the structure was also highlighted.