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14th International Conference on Non-Conventional Materials and Technologies for Sustainable engineering, NOCMAT 2013

作者： Lima, Paulo Roberto Lopes Filho, Romildo Dias Toledo Da Fonseca Martins Gomes, Otávio 1Post-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 Bahia 44036-900 Brazil Civil Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Centre for Mineral Technology-CETEM Av. Pedro Calmon 900 21941-908 Rio de Janeiro Brazil University of Liege GeMMe Georesources and Geoimaging Sart Tilman B52 4000 Liege Belgium

ISBN: (纸本)9783037859810

In this work it was studied the influence of recycled fine aggregate obtained from construction and demolition waste (CDW) on the rheological properties of Portland cement mortars. The CDW was initially separate in their main constituents (mortar, ceramic and concrete debris) at the laboratory and then grinded separately to the sand size in order to generate more homogeneous fine aggregates. The characterization of the natural and recycled sands was carried out through physical tests, X-ray diffraction, scanning electron microscopy (SEM), and image analysis (shape and texture description parameters). A conventional mortar and three mortars containing recycled sands were produced with a sand/cement ratio of 4 and consistency index of 255±5 mm. The consistency was kept constant by ranging the water-cement ratio from 0.58 to 1.14. The rheological study was performed using a rotating viscometer to obtain torque-rotation ratio and to calculate the yield stress and plastic viscosity. The results indicate that the presence of recycled aggregate causes a lowering of both yield stress and plastic viscosity with respect to the mortar containing natural aggregate. © (2014) Trans Tech Publications, Switzerland.

关键词： Mortar

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Characterization of contacts degradation in circuit breakers through the dynamic contact resistance

Characterization of contacts degradation in circuit breakers...

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IEEE/PES Transmission and Distribution Conference and Exposition: Latin America

作者： R. T. de Souza E. G. da Costa A. C. de Oliveira W. de V. Sousa T. C. M. de Morais Industry Academic Unit Paraiba Federal Institute Brazil Department of Electrical Engineering Campina Grande Federal University Brazil Post-Graduate Program in Electrical Engineering - PPgEE - COPELE - DEE Campina Grande Federal University Brazil Encrgisa Paraiba Brazil

Static resistance measurement of circuit breakers has been a crucial technique to assess the state of contacts, supporting maintenance procedures. However, in many cases, the obtained results do not provide accurate data for correct diagnosis, since the test examines only the main contact. This article discusses the application of the contact dynamic resistance measurement (DRM) in the evaluation of main and arcing contacts. The DRM is a contact resistance test, and the resistance is determined during the opening of contacts, analyzing the main and arcing contacts. The research objective is to get the DRM parameters that can assist in the contacts diagnosis. The obtained results indicate that DRM has presented more qualitative parameters than the static resistance test in the evaluation of contacts. The resistance tests were performed applying a direct current with 300 A of ***.

关键词： Resistance Circuit breakers Electrical resistance measurement Current measurement Voltage measurement Contacts Oscilloscopes

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One and Two Dc-Links Universal Active Power Filter Without Series Isolation Transformer

One and Two Dc-Links Universal Active Power Filter Without S...

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IEEE Energy Conversion Congress and Exposition

作者： P. L. S. Rodrigues C. B. Jacobina G. A. de A. Carlos M. B. R. Correa M. A. Vitorino Post-Graduate Program in Electrical Engineering - PPgEE - Copele Federal University of Campina Grande (UFCG) Campina Grande - 58429-900 - Paraiba - Brazil Department of Electrical Engineering Federal University of Campina Grande (UFCG) Campina Grande - 58429-900 - Paraiba - Brazil

ISBN: (纸本)9781479957774

This paper presents two universal active power filter (UAPF) configurations for reactive power and harmonic compensation without series isolation transformer. The proposed systems combine both series and shunt compensation, by using converters with one (configuration I) or two (configuration II) dc-links. They are suitable for applications in which size, weight and cost associated with transformers becomes a critical issue. The PWM techniques and complete control of the systems are developed. Simulation and experimental results are shown for validation purposes.

关键词： isolation transformer active power filter power filters shunt compensation harmonic compensation series (mathematics) Reactive power Transformer Converters Universal

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Hybrid Open-End and NPC AC Six-Phase Machine Drive Systems

Hybrid Open-End and NPC AC Six-Phase Machine Drive Systems

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IEEE Energy Conversion Congress and Exposition

作者： Victor F. M. B. Melo Cursino B. Jacobina Nady Rocha Post-Graduate Program in Electrical Engineering - PPgEE - COPELE - UFCG Campina Grande Paraiba Brazil Electrical Engineering Department - Federal University of Campina Grande - UFCG Campina Grande Paraiba Brazil Federal University of Paraiba - UFPB Joao Pessoa Paraiba Brazil

ISBN: (纸本)9781479957774

This paper presents two machine drive system based on a six-phase machine (SPM) and three-leg converters. The machine is composed of two three-phase groups. For the first configuration, one of the groups is connected to a three-leg converter and the other is connected to other two three-leg converters in an open-end winding configuration (see Fig. 4). For the second configuration, one of the groups is connected to a three-leg converter (similar to first one) and the other group is connected to a three-level NPC converter (see Fig. 5). Since the machine two groups are fed differently, the system topology is considered to be hybrid. The purpose of these topologies is to be an alternative configuration, being midway between the conventional six-leg inverter system (see Fig. 1) and the NPC six-leg inverter system (see Fig. 2) and Conventional twelve-leg Open-end inverter system (see Fig. 3). Compared with the conventional six-leg system, the proposed systems permits reducing the power processed by the semiconductor switches and their ratings, the dc-link voltage and the harmonic distortion. On the other hand, the proposed systems constitute less complex alternatives, compared with the open-end and NPC counterparts (see Fig. 3). PWM and control strategies are discussed. Simulation and experimental results are also presented.

关键词： drive train Figs Thyristors Converters machine six-phase Midway Inventors Harmonic distortion

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Modulation diversity effects in rayleigh fading multipath channels

Modulation diversity effects in rayleigh fading multipath ch...

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International Symposium on Telecommunications

作者： Raphael Tavares de Alencar Matheus de Araújo Cavalcante Waslon Terllizzie Araújo Lopes Wamberto José Lira de Queiroz Marcelo Sampaio de Alencar Federal University of Campina Grande (UFCG) Brazil Post-Graduate Program in Electrical Engineering-PPgEE-COPELE Institute for Advanced Studies in Communications (IECOM) Brazil Universidade Federal de Campina Grande Campina Grande PB BR

The wireless channel has characteristics of multipath fading, due to reflection, refraction and scattering. Modulation diversity is a bandwidth-efficient diversity technique that uses rotation, associated with the interleaving between the in-phase and quadrature components of a digital signal constellation. It is intended to mitigate the effects of fading in wireless communications. The research considered a scenario in which multiple paths are simulated, with associated random multiplicative noise and delay. The multipath fading effect is studied in this scenario, and a comparison between the BER values for 4-PSK and 8-PSK transmission is presented, to evaluate the gain provided by the modulation diversity scheme. An analysis concerning optimum rotation angles is performed, considering eight multipath scenarios, including cases with severe fading effect.

关键词： Fading Bit error rate Signal to noise ratio Phase shift keying Gain Wireless communication

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Six-phase open-end machine conversion system with reduced number of controlled components

Six-phase open-end machine conversion system with reduced nu...

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Annual Conference of Industrial Electronics Society

作者： Victor F. M. B. Melo Cursino B. Jacobina Nady Rocha Nustenil S. Marinus Post-Graduate Program in Electrical Engineering UFCG Electrical Engineering Department Federal University of Campina Grande - UFCG Campina Grande Paraíba Brazil Federal University of Paraíba - UFPB João Pessoa Paraíba Brazil Federal Institute of Technology of Ceara - IFCE

This paper presents two six-phase open-end machine conversion systems. They are composed of three three-leg converters connected in series to a six-phase machine with open terminals, in an open-end winding connection. The converters use diodes to replace controlled switches, making the conversion system non-reversible and with a reduced number of controlled components. In this case, the machine must work always as a generator. A study concerning harmonic distortion and semiconductor losses is carried out. PWM and control strategies are developed. Simulation and experimental results in order to test these strategies are presented.

关键词： Topology Voltage control Harmonic distortion Control systems Generators Pulse width modulation Windings

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Real-time load forecasting for demand side management with only a few days of history available

Real-time load forecasting for demand side management with o...

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2013 4th International Conference on Power engineering, Energy and Electrical Drives, POWERENG 2013

作者： Neusser, Lukas Canha, Luciane Neves Post Graduate Program in Electrical Engineering Federal University of Santa Maria - UFSM Santa-Maria Brazil

ISBN: (纸本)9781467363921

The penetration of distributed generation is growing, and today it is not unusual to see at the same site, equipment that consumes energy working side by side with power sources. To manage and optimize the use of every resource, and to avoid unbalances when the system operates near its limits, the need for very short-term load forecasting is inevitable. In this paper, the use of an already known, fast forecast algorithm, based on double seasonal exponential smoothing is proposed. His real-time usability, with only limited historical data are tested, and the mechanism behind to achieve that are explained. Results, the functionality and reliability on a real world system are also presented and discussed, leading to some concluding remarks at the end of the paper. © 2013 IEEE.

关键词： Forecasting

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SAPF with two Dc-links and series converters feeding OEW transformers for 3P4W systems

SAPF with two Dc-links and series converters feeding OEW tra...

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Annual Conference of Industrial Electronics Society

作者： Gregory A. de A. Carlos Cursino B. Jacobina Euzeli C. dos Santos Department of Control and Industrial Process Federal Institute of Alagoas (IFAL) Palmeira dos Índios - 57601-220 - Alagoas - Brazil Post-Graduate Program in Electrical Engineering - PPgEE - Copele Federal University of Campina Grande (UFCG) Campina Grande Paraíba Brazil Department of Electrical and Computer Engineering Purdue School of Engineering and Technology (IUPUI) Indiana USA

This paper presents a shunt active power filter (SAPF) topology, based on the concept of a transformer with open-end winding (OEW), for reactive power and harmonic compensations employed in three-phase four wire (3P4W) systems under balanced and unbalanced conditions. The proposed system uses two independent dc-links and two independent converters series connected through transformers. Complete system control, including PWM technique, is developed and a comparison between the proposed SAPF and conventional one is presented as well. Simulation and experimental results are provided to validate the theoretical approach.

关键词： Topology Pulse width modulation Capacitors Voltage control Optimization Harmonic analysis Power system harmonics

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A feasibility study of recycling of construction and demolition waste for structural purposes

Journal of Solid Waste Technology and Management

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Journal of Solid Waste Technology and Management 2013年第3期39卷 204-213页

作者： Mariano, Leila Seleme Da Costa, Marienne Do Rocio De Mello Maron Braga, Maria Cristina Borba Brasilian Air Force Integrated Air Traffic and Control Center - CINDACTA II Brazil Parana Federal University Department of Civil Engineering Civil Engineering Post-Graduate Program Brazil Parana Federal University Department of Hydraulics and Sanitation Water Resources and Environmental Engineering Post-Graduate Program Brazil Universidade Federal do Paraná Setor de Tecnologia Centro Politécnico - Jardim das Américas CxP 19011 81531-980 Curitiba - Paraná Brazil

The environmental problems related to construction and demolition waste involve their final dis-posal and the use of raw materials. The main goal of this research was to manage on site con-struction and demolition waste and generate concrete for structural purposes by processing concrete and mortar wastes. A Construction and Demolition Waste Management Plan (CDWMP) was developed for this study and applied by means of the implementation of recy-cling procedures. This plan included quantifying wastes and analyzing their generation. The concrete and mortar wastes were separated for recycling to produce concrete in which these wastes, respectively, replaced fractions of coarse aggregate (crushed stone) and fine aggre-gate (sand). Tests were carried out to characterize the resulting concrete and the aggregates used. The strength of the concrete generated varied from 6 MPa to 21.4 MPa, for the same mixture. It was observed that structural concretes can be produced using recycled aggregates, however this cost is higher compared to that of concrete produced with conventional aggre-gates. It was also concluded that despite the cost of concrete production, there were environmental and economic advantages to performing and applying the CDWMP to this specific con-struction site. Copyright © 2013 Widener University.

关键词： Recycling

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Dynamic timeout power policy for network interfaces

Dynamic timeout power policy for network interfaces

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IEEE International Conference on Consumer Electronics - Berlin (ICCE-Berlin)

作者： Bruna M. J. C. Vilar Fabiano De M Silva Saulo O. D. Luiz J. J. Silva Hyggo Almeida Angelo Perkusich Post-Graduate Program in Electrical Engineering - PPgEE COPELE Embedded Systems and Pervasive Computing Laboratory Universidade Federal de Campina Grande Campina Grande PB BR Center of Electrical Engineering and Informatics Federal University of Campina Grande Campina Grande Brazil Embedded Systems and Pervasive Computing Laboratory Federal University of Campina Grande

Network interfaces are present in a variety of battery powered computer systems, such as notebooks, ultrabooks, tablets and mobile phones. Considering that the battery life is still a constraint, there are opportunities for power management by reducing the power consumption of idle network interfaces. In this work, a dynamic timeout power policy for network interfaces is presented, incorporating workload estimation and a problem optimization at runtime, thus providing power savings and suitable performance.

关键词： Heuristic algorithms Network interfaces Power demand Optimization Mobile handsets Internet Stochastic processes

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