53 resultados para Directional couplers


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Psicologia - FCLAS

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Alimentos e Nutrição - FCFAR

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Engenharia Elétrica - FEIS

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Engenharia Elétrica - FEIS

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this paper, natural frequencies were analyzed (axial, torsional and flexural) and frequency response of a vertical rotor with a hard disk at the edge through the classical modal and complex analysis. The equation that rules the movement was obtained through the Lagrangian formulation. The model considered the effects of bending, torsion and axial deformation of the shaft, besides the gravitational and gyroscopic effects. The finite element method was used to discretize the structure into hollow cylindrical elements with 12 degrees of freedom. Mass, stiffness and gyroscopic matrices were explained consistently. The classical modal analysis, usually applied to stationary structures, does not consider an important characteristic of rotating machinery which are the methods of forward and backward whirl. Initially, through the traditional modal analysis, axial and torsional natural frequencies were obtained in a static shaft, since they do not suffer the influence of gyroscopic effects. Later research was performed by complex modal analysis. This type of tool, based on the use of complex coordinates to describe the dynamic behavior of rotating shaft, allows the decomposition of the system in two submodes, backward and forward. Thus, it is possible to clearly visualize that the orbit and direction of the precessional motion around the line of the rotating shaft is not deformed. A finite element program was developed using MATLAB (TM) and numerical simulations were performed to validate this model. Natural frequencies and directional frequency forced response (dFRF) were obtained using the complex modal analysis for a simple vertical rotor and also for a typical drill string used in the construction of oil wells.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present work aims to study the stability and control of the aircraft AF-X of AeroFEG team for AeroDesign to contribute with it in developing its theoretical project report for the competition and present the shortcomings of stability that it might measures for the practical test. In the first moment, it was presented forces and motion of the aircraft, so to define the equations of motion. After the equations of motion were calculated, the transfer functions were found and the aircraft response was analyzed under longitudinal stability and lateral-directional. We obtained responses from the aircraft and through the method of Root Locus the gains required to improve responses and reduce the overshoot, finally some changes and improvements for increased stability have been addressed. The study covered all the motions and control surfaces of the aircraft, showing the characteristics and behavior of the front disruptions, as well as opportunities for gains and improvementsThe present work aims to study the stability and control of the aircraft AF-X of AeroFEG team for AeroDesign to contribute with it in developing its theoretical project report for the competition and present the shortcomings of stability that it might measures for the practical test. In the first moment, it was presented forces and motion of the aircraft, so to define the equations of motion. After the equations of motion were calculated, the transfer functions were found and the aircraft response was analyzed under longitudinal stability and lateral-directional. We obtained responses from the aircraft and through the method of Root Locus the gains required to improve responses and reduce the overshoot, finally some changes and improvements for increased stability have been addressed. The study covered all the motions and control surfaces of the aircraft, showing the characteristics and behavior of the front disruptions, as well as opportunities for gains and improvements

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The biometric characteristics have been used increasingly as a way to identify an individual, mainly for security reasons. Among them, the fingerprint is the most used biometric characteristic around the world, because it is relatively simple and very efficient. In this scene, there was a significant increase in the size of databases containing information on fingerprints, necessary to perform the recognition of a person. The task of classifying them beforehand has become extremely important as it reduces dramatically the size of the problem during a search, because it is not necessary to go through the whole database. Considering its importance, in the last thirty years, many techniques have been developed to try to increase the efficiency of the classification process. This project followed the rules-based approach and the Software Development Kit (SDK) VeriFinger 6.1 was used to assist in the detection of cores and deltas. Additionally, the classification was also implemented by means of directional map and the Poincar´e index. To make the experiments, the number four database from the National Institute of Standards and Technology (NIST) was used, which is a standard in this area

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The research addresses the need for detailed geological and geotechnical investigations in pipeline’s design, given the diversity of geological units crossed by these works along its layout, which often extends for hundreds of miles. For its large size, this type of work often goes through different states and regions with very different characteristics in terms of topography, vegetation, geology and geotechnical conditions. For a better use of these investigations in order to avoid unnecessary costs and inefficient results, some authors recommend that steps be taken to study, seeking a progressive detail of the pipeline’s implantation area. The main objective of the study is to describe, analyze and correlate the proposals for geological and geotechnical’s investigation recommended by the authors selected. Nogueira Junior & Marques (1998) suggest that for better effectiveness of geological and geotechnical investigations associated with the deployment of pipelines, different research methods are applied sequentially in five major stages of the building. Rocha et al (2008) recommend that, for the pipeline’s implantation using horizontal directional drilling, investigations are performed in three phases of study, to be developed in coordination with the project stages. For Gelinas & Mathy (2004), when time and budget constraints permit, geotechnical investigations for directional drilling projects for pipelines must be made in four sequential phases. Heinz (2008) suggests that the geotechnical investigations for pipeline’s implantation using horizontal directional drilling at crossings of water bodies are carried out in three successive stages. By the development of research, we could see that all the different proposals recommend studies in sequential phases, starting from a more general scale for a more specific, seeking a progressive understanding of the geological model of the area where you intend to deploy the pipeline