Fast Fourier Transform
Mostrando 13-24 de 88 artigos, teses e dissertações.
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13. Comparison of In-Flight Measured and Computed Aeroelastic Damping: Modal Identification Procedures and Modeling Approaches
ABSTRACT The Operational Modal Analysis technique is a methodology very often applied for the identification of dynamic systems when the input signal is unknown. The applied methodology is based on a technique to estimate the Frequency Response Functions and extract the modal parameters using only the structural dynamic response data, without assuming the kn
J. Aerosp. Technol. Manag.. Publicado em: 2016-06
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14. Comparison of Gold CD-R Types as Electrochemical Device and as Platform for Biosensors
The construction of gold electrodes using 3 kinds of gold recordable compact discs (CDtrodes) and characterization by electrochemical and spectroscopic techniques are herein reported. Following a surface pretreatment in 0.5 mol L-1 sulfuric acid (H2SO4), the electrochemical experiments were performed in the presence of redox couple ferro/ferricyanide [Fe(CN)
J. Braz. Chem. Soc.. Publicado em: 2016-04
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15. A simple approach to calculate active power of electrosurgical units
Abstract Introduction: Despite of more than a hundred years of electrosurgery, only a few electrosurgical equipment manufacturers have developed methods to regulate the active power delivered to the patient, usually around an arbitrary setpoint. In fact, no manufacturer has a method to measure the active power actually delivered to the load. Measuring the d
Res. Biomed. Eng.. Publicado em: 05/02/2016
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16. Correlation Between Fuel Lubricity and Vibration Signals Obtained in Ball-disc Analysis Using Fourier Transform
During the contact between metallic surfaces in mechanical systems, some dynamic characteristics present significant changes as the vibration signal patterns. The acquisition and characterization of these signals, by the use of Fourier Transform (FT), are non-intrusive tools in the evaluation of lubricity. This study aimed to evaluate dynamically the fuels l
Mat. Res.. Publicado em: 24/11/2015
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17. Electromechanical Impedance - Based Structural Health Monitoring Instrumentation System Applied to Aircraft Structures and Employing a Multiplexed Sensor Array
ABSTRACT: The electromechanical impedance method has been seen as a promising tool for structural health monitoring regarding different types of structures and purposes. Most importantly, this method can be used in real-time applications. Frequently, massive, high-cost, single-channel impedance analyzers are used to process the time domain data, aiming at ob
J. Aerosp. Technol. Manag.. Publicado em: 2015-09
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18. Facile Graphene Oxide Preparation by Microwave-Assisted Acid Method
Few-layered graphene oxide (GO) was prepared using a fast and energy-saving method by microwave-assisted acid technique. The oxygenated groups existing on the GO surface were determined using UV-Vis, X-ray photoelectron and Fourier-transform infrared spectroscopies. An oxygenated group percentage of 30% in mass for the GO was observed by thermogravimetric an
J. Braz. Chem. Soc.. Publicado em: 2015-05
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19. Seismic response of aboveground steel storage tanks: comparative study of analyses by six and three correlated earthquake components
Ground motions at a point on the ground surface can be decomposed to six components, namely three translational components and three rotational components; translational components include two components in the horizontal plane, and one in the vertical direction. Rotation about horizontal axes leads to rising of rocking, while the rotational component about
Lat. Am. j. solids struct.. Publicado em: 2013-11
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20. Case depth in SAE 1020 steel using barkhausen noise
The most widely used thermochemical process for surface hardening of steels is case hardening. Using several different heat treatments, martensitic surface layers were formed on SAE 1020 steel into which carbon had been diffused. Case depths were measured by traditional destructive techniques. Barkhausen noise measurements were made and both the RMS Barkhaus
Mat. Res.. Publicado em: 18/06/2013
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21. Non-linear dynamics of a hanging rope
Two-dimensional motion of a hanging rope is considered. A multibody system with elastic-dissipative joints is used for modelling of the rope. The mathematical model based on the Lagrange formalism is presented. Results of some numerical simulations are shown for the mechanical system with kinematic excitation. Basic tools are used to qualify dynamics of the
Lat. Am. j. solids struct.. Publicado em: 2013-01
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22. Filtros digitais por transformadas de Fourier aplicados em eletroquímica
The electrochemical properties of micro and nano-electrodes are widely investigated due to their low faradaic and capacitive currents, leading to a new generation of smart and implantable devices. However, the current signals obtained in low-dimensional devices are strongly influenced by noise sources. In this paper, we show the evaluation of filters based o
Quím. Nova. Publicado em: 2013
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23. Desenvolvimento de ferramenta de comparação de técnicas de processamento de sinais para determinar fadiga muscular por meio do sinal emg / Toolkit development for signals processing technics comparison to detect muscular fadigue by EMG signal
This study aimed to development of a computational tool for electromyographic signal (EMG) analysis by signal processing techniques to determine muscular fatigue. With Ethics Committee of Federal University of Goiás approve were recorded from the dominant biceps brachii of 10 volunteers, that did not ever had muscular disease. The protocol consisted on get
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/07/2012
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24. Transient wave propagation phenomena at visco-elastic half-spaces under distributed surface loadings
This article analyzes the transient wave propagation phenomena that take place at 2D viscoelastic half-spaces subjected to spatially distributed surface loadings and to distinct temporal excitations. It starts with a fairly detailed review of the existing strategies to describe transient analysis for elastic and viscoelastic continua by means of the Boundary
Lat. Am. j. solids struct.. Publicado em: 2012-08