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作者： Santos, Rogério De Jesus Lima, Paulo Roberto Lopes Post-graduate Program of Civil and Environmental Engineering Department of Technology State University of Feira de Santana Av. Transnordestina S/N-Novo Horizonte Feira de Santana Bahia44036-900 Brazil

The dimensional instability of vegetable fibers due to hygroscopicity results in a gradual loss of adherence in cement based composites which, when in service, are submitted to a natural variation of humidity. Such an effect reduces the contribution of the fiber as a reinforcement and can cause the early rupture of the material. In this work, a treatment of the sisal fibers is performed with the applying of wetting-drying cycles in order to alter their crystalline structure and improve the dimensional stability of the fiber to withstand the variation of humidity: 6, 10, 20, 30 and 34 cycles were applied in order to evaluate the effect on the properties of fiber;a tensile test, the morphological characterization (MEV) and the evaluation of the chemical structure of fiber were carried out. The effect of the treatment on fiber-matrix behavior was evaluated using the pull-out test. Embedded lengths of 16, 20, 30, 40 and 44 mm were defined through a factorial design and used in the test. It is verified that the use of 10 wetting-drying cycles causes less damage to the tensile strength and the elastic modulus of the fiber and contributes to a better adherence with the matrix, with an increase of up to 23 % compared with the untreated fiber. The statistical analysis of the interaction effect between the studied factors, using 2K factorial design with central composite design, indicates that the number of cycles can be decreased when using a longer length of the embedded fiber. © (2015) Trans Tech Publications, Switzerland.

关键词： Tensile strength

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Modeling and control of the modular multilevel cascade converter based on chopper-cells for grid-connected photovoltaic systems 7

Modeling and control of the modular multilevel cascade conve...

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7th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2015

作者： Luna, Bruno Emmanuel De O. B. Jacobina, Cursino B. Oliveira, Alexandre C. Da Silva, Italo Roger F. M. P. Post-graduate Program in Electrical Engineering - PPgEE/COPELE Aprígio Veloso 882 Campina Grande-PB58429-900 Brazil Aprígio Veloso 882 Campina Grande-PB58429-900 Brazil

ISBN: (纸本)9781467371506

This paper presents a modular multilevel cascade converter (MMCC) based on chopper-cells for a grid-connected photovoltaic (PV) application suitable to medium and high voltage systems without line-frequency transformers. This converter is characterized by a modular arm structure composed by cascaded chopper-cells with floating dc capacitors, each one connected to a photovoltaic panel. This paper proposes a continuous model and a control method to achieve independent voltage control of all the floating dc capacitors, enabling the tracking of the maximum power point for each photovoltaic panel. The validity of the theory is confirmed by simulation and experiment. © 2015 IEEE.

关键词： Choppers (circuits)

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Transformation of dwelling culture based on riverine community in Musi River Palembang

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AIP Conference Proceedings 2017年第1期1903卷

作者： Bambang Wicaksono Ari Siswanto Susilo Kusdiwanggo Widya Fransiska Febriati Anwar 1Department S3 Engineering Science Post Graduate Program Sriwijaya University Jl. Palembang Prabumulih Km. 32 Inderalaya (OI) Indonesia 2Department Architecture Engineering Sriwijaya University Jalan Srijaya Negara Bukit Lama Ilir Barat I Kota Palembang Sumatera Selatan 30128 Indonesia 3Department Architecture Engineering Brawijaya University Jalan Mayjen Haryono 167 Malang Jawa Timur 65145 Indonesia

Palembang City development since the Palembang Darussalam Sultanate era to the reformation era has impact on the living culture community, less of the raft houses, houses on stilts transformed into a terraced house, and the house became the dominant land. Dwelling Culture oriented on transformation of river become land-oriented. The development has leaving identity, character, and potential of the riverine architecture and dwelling life of river. The goals of study are to describe a case and revealing the meaning of dwelling cultural transformation in Musi River society from the process of cultural acculturation and investigate the architectural aspect from the form of house and modes of dwelling through the structuralism approach. The data collection is conducted qualitatively by using data collection techniques such as observation, interview, literature study, whereas the method of analysis, is a method that is done through Levi-Strauss structuralism approach that identifies all the elements of community thought in a systematic procedure. The results showed the structure behind the orientation, position, shape, and layout of dwelling revealed through the meanings in it. It means, the change and development from cultural acculturation process which oriented in the land dwelling, based on structure thinking of Palembang society.

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Low-power energy generation systems for two-phase PM machine with reduced-switch-count controlled switches 7

Low-power energy generation systems for two-phase PM machine...

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7th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2015

作者： Bahia, Filipe A. Da C. Jacobina, Cursino B. Rocha, Nady Da Silva, Italo Roger F. M. P. Salvadori, Fabiano Post-Graduate Program in Electrical Engineering PPgEE COPELE UFCG Brazil Department of Electrical Engineering Federal University of Campina Grande UFCG Campina Grande Paraíba Brazil Department of Engineering Federal University of the Paraíba UFPB João Pessoa Paraíba Brazil

ISBN: (纸本)9781467371506

This paper presents two power generation systems with a two-phase permanent magnet (PM) synchronous machine associated to a rectifier with small number of controlled switches. The topologies have as main purpose converting wind energy into electrical energy for low power applications, providing a great potential to be used in urban areas. They can be used in applications connected to the grid or in the stand-alone mode or feeding a micro grid. Compared with two three-phase generation systems that use reduced number of controlled switches, the proposed topologies permit obtaining sinusoidal machine currents, with low harmonic distortion, using a smaller number of controlled switches. Simulation and experimental results also are presented. © 2015 IEEE.

关键词： Topology

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A Family Of Single-Phase Current Source Converters With Double Outputs

A Family Of Single-Phase Current Source Converters With Doub...

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Annual IEEE Applied Power Electronics Conference and Exposition

作者： Louelson A. Costa Maurício B. R. Corrêa Montiê A. Vitorino Gutemberg G. dos Santos Darlan A. Fernandes Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Department of Electrical Engineering Federal University of Campina Grande (UFCG) Campina Grande - PB - Brazil Department of Electrical Engineering Federal University of Paraiba (UFPB) Joao Pessoa - PB - Brazil

ISBN: (纸本)9781467395519

This work introduces a family of Current Source Converters (CSCs) that allows to control single-phase AC converters with two outputs independently sharing the same DC-bus. It is presented four different topologies which have their own advantages and disadvantages compared to each other. The comparison criterias are the total number of switches, the number of conducting switches per switching cycle, quadrant operations and DC-bus current. One of the topologies needs to always have four conducting switches with full-quadrant operation (named Fq4c), while another topology (Lq2c) needs only two, however with limited-quadrant operation. The last two presented topologies have three conducting switches in a switching period, one with full-quadrant operation (Fq3c) and another with limited-quadrant operation (Lq3c). Also it is presented the Scalar Pulse Width Modulations (SPWMs) to control each converter with switching optimization. Details of the topologies, operation and modulation logic are presented. Simulations and experimental results are provided to validate the theoretical approach.

关键词： SPWMs Family Single-Phase Current Source Converters Double Outputs

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Towards a Robotic Knee Exoskeleton Control Based on Human Motion Intention through EEG and sEMGsignals

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Procedia Manufacturing 2015年 3卷 1379-1386页

作者： Villa-Parra, A.C. Delisle-Rodríguez, D. López-Delis, A. Bastos-Filho, T. Sagaró, R. Frizera-Neto, A. Post-Graduate Program in Electrical Engineering Universidade Federal do Espírito Santo Vitória Brazil GIIB Universidad Politécnica Salesiana Cuenca Ecuador Center of Medical Biophysics Universidad de Oriente Santiago Cuba Mechanical and Design Engineering Department Universidad de Oriente Santiago Cuba

The integration of lower limb exoskeletons with robotic walkers allows obtaining a system to improve mobility and security during gait rehabilitation. In this work, the evaluation of human motion intention (HMI) based on electroencephalogram (EEG) and surface electromyography (sEMG) signals are analyzed for a knee exoskeleton control as a preliminary study for gait neuro-rehabilitation with a hybrid robotic system. This system consists of the knee exoskeleton H2 and the UFES's Smart Walker, which are used to restore the neuromotor control function of subjects with neural injuries. An experimental protocol was developed to identify patterns to control the exoskeleton in accordance with the HMI-based on EEG/sEMG. The EEG and sEMG signals are recorded during the following activities: stand-up/sit-down and knee flexion/extension. HMI is analyzed through both event-related desynchronization/synchronization (ERD/ERS) and slow cortical potential, as well as the myoelectric pattern classification related to lower limb. The feature extraction from sEMG signals is based on vector combinations in time and frequency domain which are used for a pattern classification stage trough an artificial neural network with Levenberg Marquadt training algorithm and support vector machine. Preliminary results shown that a combination of EEG/sEMG signals can be used to define a control strategy for the robotic system. © 2015 The Authors

关键词： EEG Human-motion-intention Knee exoskeleton Pattern recognition sEMG

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Measurement equipment for characterization of ferromagnetic materials

Measurement equipment for characterization of ferromagnetic ...

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IEEE Instrumentation and Measurement Technology Conference

作者： Tarcísio Oliveira de Moraes Raimundo Carlos Silvério Freire Débora Albuquerque Vieira Cleonilson Protásio de Souza Post-Graduate Program in Electrical Engineering - PPGEE Federal University of Campina Grande UFCG Campina Grande PB BR Federal University of Campina Grande UFCG Brazil Post-Graduate Program in Electrical Engineering - PPGEE/UFPB Federal University of Paraíba UFPB Brazil Post-Graduate Program in Electrical Engineering - PPGEE/UFPB Federal University of Paraiba João Pessoa Brazil

Ferromagnetic materials have magnetic properties which determine its magnetic field conductivity characteristics. Such characteristics are extremely important for the proper selection and use of these materials in measurement processes, for example. Therefore, this paper presents an equipment for the characterization of ferromagnetic materials constructed in a laboratory. The experimental results of this equipment are acquired and compared with the experimental results obtained with an industrially manufactured apparatus called hysteresisgraph, designed to provide magnetic characterization of magnetic materials. The results of the comparison demonstrate that the equipment presented has low relative error and can be applied in academic projects which require magnetic characterization of ferromagnetic materials developed in the laboratory.

关键词： Magnetic hysteresis Magnetic materials Magnetic flux Magnetic field measurement Magnetic cores Voltage measurement Magnetic fields

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An automatic voltage disturbance classification system based on Clonal Selection Algorithm

An automatic voltage disturbance classification system based...

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2015 IEEE International Instrumentation and Measurement Technology Conference, I2MTC 2015

作者： De Souza Arruda, Bruno Willian Freire, Raimundo Carlos Silverio De Souza, Cleonilson Protasio Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Department of Electrical Engineering Federal University of Campina Grande - UFCG Campina Grande Paraíba Brazil Center of Renewable and Alternative Energy Department of Electrical Engineering Federal University of Paraíba João Pessoa Paraíba Brazil

ISBN: (纸本)9781479961139

Classification of voltage disturbances in power systems is essential for modern society and can be very demanding according to the used method or the aimed accuracy. This paper presents a new intelligent approach aimed to automatically analyse power quality disturbances including sag, swell, outage, harmonics and normal waveform. The approach is based on Artificial Immune System and focuses on the application of a Clonal Selection Algorithm to extract features from disturbance waveforms and classify the disturbances in each 0.5 cycle of the fundamental frequency. Other important feature of the proposed approach is that it can be embedded since the resulted on-line classification tool achieves very low computational complexity. Comparisons and experimental results obtained from the application of the proposed method validate the approach and achieved a classification accuracy at least better than previous work. © 2015 IEEE.

关键词： Power quality

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An embedded asterisk platform instructional design to teach voice over IP in information technology undergraduate courses: Using raspberry PI and asterisk to build an embedded portable didactic tool 7

An embedded asterisk platform instructional design to teach ...

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7th International Conference on Computer Supported Education, CSEDU 2015

作者： Dias, M.C. Bezerra, L.C. Morais, D. Gabi, C.F. Perkusich, A. Electrical Engineering Coordination Laboratory of Telephony and Convergent Networks - LTCON Federal Institute of Education Science and Technology of Paraíba - IFPB João Pessoa Brazil Post-graduate Program in Electrical Engineering - PpgEE - COPELE Electrical Engineering Department Federal University of Campina Grande - UFCG Campina Grande Brazil

ISBN: (纸本)9789897581076

This paper shows the building of an embedded Asterisk platform as a key technique for providing Information Technology classes with an extra laboratorial environment for learning Voice over Internet Protocol. Besides building the platform, the students are asked to mount a functional telephony system with it that meets the criteria of low cost, low building complexity and high adaptability to convergent networks. The Raspberry PI version B was the board used to provide portability for the students to work outside the laboratory environment. Asterisk was presented as a useful tool on which the students could create a flexible system that could be easily deployed on convergent networks. This work was developed in the Telephony subject for the Electrical engineering and the Telecommunications Systems undergraduate courses from the Federal Institute of Education, Science and Technology of Paraíba - IFPB, and presented good results in the students' learning achievements.

关键词： Students

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Analysis of the possible failure modes in CSH bolted sleeve connections 15

Analysis of the possible failure modes in CSH bolted sleeve ...

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Proceedings of the 15th International Symposium on Tubular Structures, ISTS 2015

作者： Amparo, L.R. Sarmanho, A.M. De Araújo, A. Requena, J. Post-Graduate Program in Civil Engineering Federal University of Ouro Preto Ouro PretoMG Brazil V&M do Brasil S. A Belo HorizonteMG Brazil State University of Campinas CampinasSP Brazil

ISBN: (纸本)9781138028371

Steel circular hollowsections (CHS) have good resistance under tension, compression and torsion loads, considered isolated or combined. Recent researches have been carried out to evaluate the behavior and resistance of these structures. A current use of steel hollow sections is roof trusses, a kind of structure that demands standard procedures and fast assemblage. This work presents an experimental study of a new type of connection called sleeve, developed to attend the assembly process. The connection consists of two tubes internally connected through a third tube with a smaller diameter with passing bolts arranged in line and cross. This connection makes easier the structure assemblage and is aesthetically advantageous if compared to usual flanged connection used in hollow sections. An experimental program of the sleeve connection with bolts in line (along the tube) and crossed at 90◦ was developed. In this work were tested 3 prototypes with staggered bolts to complement previous research and 12 prototypes with crossed bolts. The parameters considered in investigation were tube diameter and thickness and number of bolts. Experimental results lead to identification of failure mode and the resistance of sleeve connection. The analysis of theoretical and experimental data revealed that the dominant failure mode was bending in the bolts, and indicated a reduction in connection resistance that needs to be quantified. For the prototypes with staggered bolts, the analysis also let the development of an expression for the determination of flexural failure in the bolts. The results have demonstrated the viability of this new type of connection, but indicated that all possible failure modes need to be carefully checked. © 2015 Taylor & Francis Group, London.

关键词： Failure modes

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