Active vibration control using delayed resonant feedback

Delayed feedback (DF) control is a well-established technique to suppress single frequency vibration of a non-minimum phase system. Modal control is also a well-established technique to control multiple vibration modes of a minimum phase system. In this paper these techniques are combined to simultaneously suppress multiple vibration modes of a non-minimum phase system involving a small time delay. The control approach is called delayed resonant feedback (DRF) where each modal controller consists of a modal filter to extract the target mode signal from the vibration response, and a phase compensator to account for the phase delay of the mode. The methodology is first discussed using a single mode system. A multi-mode system is then studied and experimental results are presented to demonstrate the efficacy of the control approach for two modes of a beam. It is shown that the system behaves as if each mode under control has a dynamic vibration absorber attached to it, even though the actuator and the sensor are not collocated and there is a time delay in the control system. © 2013 IOP Publishing Ltd.

Local data fusion algorithm for fire detection through mobile robot

Multisensor data fusion is a technique that combines the readings of multiple sensors to detect some phenomenon. Data fusion applications are numerous and they can be used in smart buildings, environment monitoring, industry and defense applications. The main goal of multisensor data fusion is to minimize false alarms and maximize the probability of detection based on the detection of multiple sensors. In this paper a local data fusion algorithm based on luminosity, temperature and flame for fire detection is presented. The data fusion approach was embedded in a low cost mobile robot. The prototype test validation has indicated that our approach can detect fire occurrence. Moreover, the low cost project allow the development of robots that could be discarded in their fire detection missions. © 2013 IEEE.

The dynamic behaviour of a buried water pipe and its effect on leak location using acoustic methods

Leakage in buried pipes is one of the main concerns for water companies due to the scarcity of potable water sources. Older metallic pipelines have been replaced by plastic pipes in such systems, which makes it more difficult to locate leaks using acoustics and vibration. This is mainly because of the high attenuation of leak signals caused by the damping in the pipe wall. To investigate acoustic methods in leak location in controlled conditions, a bespoke test rig was constructed in the UK. In this paper, data from this test-rig is used to discuss some issues that arise when using two contemporary correlators. Of particular interest, is the way in which a resonance in the system can have a profound effect on the estimate of the position of the leak depending on the way in which the leak noise signals are processed. © (2013) Trans Tech Publications.

Desenvolvimento e implementação de um sistema para detecção de falhas em estruturas usando microcontrolador

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Clonagem, análise estrutural e imunológica do alérgeno antígeno 5 do veneno da vespa Polybia paulista (Hymenoptera : Vespidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Detecção de falhas estruturais usando sensores e atuadores piezelétricos e algoritmos genéticos

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

Modelagem de estruturas piezelétricas para aplicação em localização de falhas

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

Uma Contribuição aos Sistemas de Monitoramento de Integridade Estrutural Baseados na Impedância Eletromecânica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for W ' -> tb decays in the lepton plus jets final state in pp collisions at root s=8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diagnostic accuracy of semi-quantitative and quantitative culture techniques for the diagnosis of catheter-related infections in newborns and molecular typing of isolated microorganisms

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

Mapeamento da condutividade hidráulica da cobertura do aquífero Guarani, situado na bacia hidrográfica dos rios Jacaré-Guaçú e Jacaré-Pepira, na porção centro-norte do estado de São Paulo

Given the importance of preserving the water quality of the Guarani Aquifer, the work done in the hydrographic basin of the rivers Jacaré-Guaçú e Jacaré-Pepira, located in the central-northern São Paulo state, was made to map the hydraulic conductivity from the use of some empirical methods associated with granulometric analysis and in situ testing, specifically with the Guelph permeameter. All results were submitted to a correlation analysis and subsequently mapped using the methodology of minimum curvature, based on numerical techniques Spline. These procedures provide for studies of aquifer vulnerability and assist in decision making in environmental projects and guidelines for urban planning

Monitoramento de danos estruturais utilizando sensores de nanocompósitos

Pós-graduação em Engenharia Mecânica - FEIS

Detecção de danos em estruturas guiadas usando ondas de alta frequência

Pós-graduação em Engenharia Mecânica - FEIS

Aplicação da análise de séries temporais para detecção e prognóstico de danos em estruturas inteligentes

Pós-graduação em Engenharia Mecânica - FEIS

Diffusive random laser modes under a spatiotemporal scope

At present the prediction and characterization of the emission output of a diffusive random laser remains a challenge, despite the variety of investigated materials and theoretical interpretations given up to now. Here, a new mode selection method, based on spatial filtering and ultrafast detection, which allows to separate individual lasing modes and follow their temporal evolution is presented. In particular, the work explores the random laser behavior of a ground powder of an organic-inorganic hybrid compound based on Rhodamine B incorporated into a di-ureasil host. The experimental approach gives direct access to the mode structure and dynamics, shows clear modal relaxation oscillations, and illustrates the lasing modes stochastic behavior of this diffusive scattering system. The effect of the excitation energy on its modal density is also investigated. Finally, imaging measurements reveal the dominant role of diffusion over amplification processes in this kind of unconventional lasers. (C) 2015 Optical Society of America