On a control design to an AFM microcantilever beam, operating in a tapping-mode, with irregular behavior

In last decades, control of nonlinear dynamic systems became an important and interesting problem studied by many authors, what results the appearance of lots of works about this subject in the scientific literature. In this paper, an Atomic Force Microscope micro cantilever operating in tapping mode was modeled, and its behavior was studied using bifurcation diagrams, phase portraits, time history, Poincare maps and Lyapunov exponents. Chaos was detected in an interval of time; those phenomena undermine the achievement of accurate images by the sample surface. In the mathematical model, periodic and chaotic motion was obtained by changing parameters. To control the chaotic behavior of the system were implemented two control techniques. The SDRE control (State Dependent Riccati Equation) and Time-delayed feedback control. Simulation results show the feasibility of the bothmethods, for chaos control of an AFM system. Copyright © 2011 by ASME.

On switched control design of linear time-invariant systems with polytopic uncertainties

This paper proposes a new switched control design method for some classes of linear time-invariant systems with polytopic uncertainties. This method uses a quadratic Lyapunov function to design the feedback controller gains based on linear matrix inequalities (LMIs). The controller gain is chosen by a switching law that returns the smallest value of the time derivative of the Lyapunov function. The proposed methodology offers less conservative alternative than the well-known controller for uncertain systems with only one state feedback gain. The control design of a magnetic levitator illustrates the procedure. © 2013 Wallysonn A. de Souza et al.

On the control of vibrations using synchrophasing

This paper describes the application of a technique, known as synchrophasing, to the control of machinery vibration. It is applicable to machinery installations, in which several synchronous machines, such as those driven by electrical motors, are fitted to an isolated common structure known as a machinery raft. To reduce the vibration transmitted to the host structure to which the machinery raft is attached, the phase of the electrical supply to the motors is adjusted so that the net transmitted force to the host structure is minimised. It is shown that while this is relatively simple for an installation consisting of two machines, it is more complicated for installations in which there are more than two machines, because of the interaction between the forces generated by each machine. The development of a synchrophasing scheme, which has been applied to propeller aircraft, and is known as Propeller Signature Theory (PST) is discussed. It is shown both theoretically and experimentally, that this is an efficient way of controlling the phase of multiple machines. It is also shown that synchrophasing is a worthwhile vibration control technique, which has the potential to suppress vibration transmitted to the host structure by up to 20 dB at certain frequencies. Although the principle of synchronisation has been demonstrated on a one-dimensional structure, it is believed that this captures the key features of the approach. However, it should be realised that the mode-shapes of a machinery raft may be more complex than that of a one-dimensional structure and this may need to be taken into account in a real application. © 2013 Elsevier Ltd.

Gestão da informação no jornalismo on-line: estudo do portal Campo Grande News

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Política 2.0 no Youtube: jornalismo cidadão e a campanha on-line de Barack Obama

Pós-graduação em Comunicação - FAAC

O uso de dois websites de compras on-line por usuários acima de 50 anos (older users): estudo de caso

Pós-graduação em Design - FAAC

As revistas Veja impressa e on-line em perspectiva dialógica: dois universos, dois leitores?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Predição de dados espaciais e temporais: uma ferramenta on-line baseada em recursos georreferenciados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Preferência estética do perfil facial avaliado on-line por brasileiros

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of steam thermal treatment on the drying process of Eucalyptus dunnii variables

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of saccadic eye movements on postural control stabilization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new sampling strategy to reduce the effect of autocorrelation on a control chart

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Projeto Memória Votorantim (P.M.V.): Um centro de documentação on line

Esta investigación da énfasis a la formación y consolidacón del Proyecto Memoria Votorantim (P.M.V.), presentado al gran publico en 2005, con la publicación de su sitio en la WEB. El ejecentral fundamental es compreender su “arquitetura” y los contenidos específicos de sus distintas secciones, i indentificando los conjuntos informativos los repertoriod documentale que lo intgran, buscando entender los propósitos de su constituicón, La hipótese del trabajo es que la concepción del contenido documental y la desponición de las inforaciones archivistas que cundujeron al yuxtaposición del recuerdo de los trabajadores con el recuerdo corporativo produciendo la história oficial del Grupo Votorantim. Se busca discutir la constituición del P.M.V. como parte de las estratégias del crescimento de los negocios de la Votorantim anunciados en 2004, edificando la tradición del Grupo Votorantim y actuando como refuerzo y amliación de la corporativa de sus empleados.

Do catálogo impresso ao cátalogo on-line: algumas considerações e desafios ao bibliotecário

In relation to the changes that mark the trajectory of libraries catalogs, this paper aims to describe the challenges that go beyond the current status of librarians, in relation to use of the on-line catalog as the main tool storage and retrieval of documentary information. Using literature specialized is intended to contribute to the discussion of the topic, in order to understand the challenges and prospects of using this important tool for search and information retrieval.

Investigação da colaboração científica na temática de indexação em periódicos on-line em âmbito nacional

This research seeks to demonstrate the scientific collaboration in the field of Information Science, specifically in the thematic indexing, by analyzing the co-authors network, based on scientific collaboration in Brazilian journals online, according to CAPES. We selected six Brazilian journals online, namely: Ciência da Informação; Transinformação; Perspectivas da Ciência da Informação; Encontros BIBLI: Revista Eletrônica de Biblioteconomia e Ciência da Informação; DataGramaZero and Em Questão, totaling 25 articles. It was built in coauthorship network, using Pajek software in order to evaluate interactions between researchers and cohesion of the network by calculating its density.