Desenvolvimento de um algoritmo como solução para o problema de restauração de sistemas de distribuição radiais / Development of an algorithm as a solution to the problem of restoration of radial distribution systems

O problema de restauração consiste na reenergização do maior número possível de cargas desenergizadas devido a ocorrência de uma falta permanente em alguma seção do sistema de distribuição. Este artigo apresenta uma metodologia robusta e eficiente para o problema de restauração de sistemas de distribuição radiais. O modelo para resolver o problema de restauração em um sistema radial deve ter como objetivo principal restaurar o máximo de carga possível da região afetada em um curto prazo de tempo. O problema de restauração é de origem combinatória e originalmente é modelado como um problema de programação não linear inteira mista. A restauração é essencial para garantir a confiabilidade e qualidade do serviço, além de reduzir o tempo de interrupção. O algoritmo desenvolvido é composto pela meta-heurística Busca Tabu e utiliza o conceito de grafos, lista de adjacência, para manter a topologia do sistema. Os testes são realizados utilizando o sistema de 53 barras da literatura e os resultados são apresentados e avaliados

Projeto de Máquinas Síncronas de Relutância em Aplicações Veiculares

A crescente demanda por motores elétricos capazes de operar em altas velocidades, com boa produção de conjugado, tem tornado os motores de relutância síncronos competitivos e bastante empregados em aplicações veiculares, indústrias têxteis e em sistemas de bombeamento e ventilação. Em função disso, este artigo apresenta as características de projeto, modelo matemático do motor e do controle de velocidade, empregando a técnica de controle de campo orientado indireto (IFOC). Os resultados, por fim, são analisados a partir de simulação computacional

Proteomics Coupled with Metabolite and Cell Wall Profiling Reveal Metabolic Processes of a Developing Rice Stem Internode

Internodes of grass stems function in mechanical support, transport, and, in some species, are a major sink organ for carbon in the form of cell wall polymers. This study reports cell wall composition, proteomic, and metabolite analyses of the rice elongating internode. Cellulose, lignin, and xylose increase as a percentage of cell wall material along eight segments of the second rice internode (internode II) at booting stage, from the younger to the older internode segments, indicating active cell wall synthesis. Liquid-chromatography tandem mass spectrometry (LC-MS/MS) of trypsin-digested proteins from this internode at booting reveals 2,547 proteins with at least two unique peptides in two biological replicates. The dataset includes many glycosyltransferases, acyltransferases, glycosyl hydrolases, cell wall-localized proteins, and protein kinases that have or may have functions in cell wall biosynthesis or remodeling. Phospho-enrichment of internode II peptides identified 21 unique phosphopeptides belonging to 20 phosphoproteins including a leucine rich repeat-III family receptor like kinase. GO over-representation and KEGG pathway analyses highlight the abundances of proteins involved in biosynthetic processes, especially the synthesis of secondary metabolites such as phenylpropanoids and flavonoids. LC-MS/MS of hot methanol-extracted secondary metabolites from internode II at four stages (booting/elongation, early mature, mature, and post mature) indicates that internode secondary metabolites are distinct from those of roots and leaves, and differ across stem maturation. This work fills a void of in-depth proteomics and metabolomics data for grass stems, specifically for rice, and provides baseline knowledge for more detailed studies of cell wall synthesis and other biological processes characteristic of internode development, toward improving grass agronomic properties.This work was supported by the U.S. National Science Foundation (grant numbers EPS-0814361, 0923247, and CHE-1626372), the U.S. Department of Energy (DOE), Office of Science (DE-SC0006904), and the U.S. Department of Agriculture National Institute of Food and Agriculture, (2010-38502-21836). A portion of this research was performed in the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory (PNNL). The Environmental Molecular Sciences Laboratory is a DOE Office of Biological and Environmental Research scientific user facility on the PNNL campus. PNNL is a multiprogram national laboratory operated by Battelle for the DOE under contract DE-AC05-76RL01830. Collaboration with EMSL was supported through Projects 49477 and 49510. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the funding agencies. Open access fees fees for this article provided whole or in part by OU Libraries Open Access Fund.Ye

Gerador a relutância variável em conexão com a rede elétrica para injeção de potência ativa

This work shows a contribution to the study of the Switched Reluctance Machine driven as a generator to connecting in the grid to inject active power. The main objective is show the Switched Reluctance Generator behavior under various operating conditions, as well as the development of an electronic converter to connect it to the low voltage grid. Thus, it presents a mathematical model for the Switching Reluctance Generator which includes the magnetic circuit saturation and a computational model for analyzing steady state and transient. Also it is presented a strategy of generated voltage control by the magnetization angle variation acting only in the top switch of the Asymmetrical Half Bridge converter. An intermediate stage was added in the switching control strategy to reduce the energy amount provided by the excitation source and get better utilization of electromechanical conversion. A detailed description of the control system equations of the DC-AC stage, PLL algorithm and design of injected current compensator are presented and discussed. Finally, it was constructed in laboratory a experimental platform for verification of the theoretical and simulation.Doutor em CiênciasEste trabalho apresenta uma contribuição ao estudo da Máquina a Relutância Variável acionada como gerador para conexão com rede elétrica e injeção de potência ativa. O objetivo principal é apresentar o comportamento do Gerador a Relutância Variável sob diversas condições de operação, bem como o desenvolvimento de um conversor eletrônico para a sua conexão a rede elétrica de baixa tensão. Assim, é apresentado um modelo matemático para o Gerador a Relutância Variável que contempla a saturação do circuito magnético e um modelo computacional para análise em regime permanente e transitório. Também é apresentada uma estratégia de controle da tensão gerada através da variação do ângulo de magnetização atuando apenas nas chaves superiores do conversor assimétrico Half Bridge. Uma etapa intermediária no chaveamento foi acrescentada à estratégia de controle para diminuir a quantidade de energia fornecida pela fonte de excitação e obter melhor aproveitamento da conversão eletromecânica. Uma descrição detalhada do equacionamento do sistema de controle do estágio CC-CA, do algoritmo de PLL e projeto do compensador da corrente injetada são apresentados e discutidos. Por fim, construiu-se uma plataforma experimental em laboratório para a comprovação dos estudos teóricos e de simulação

Design, implementation and automation of a bench for the testing of single-phase induction motors

Submitted by JÚLIO HEBER SILVA ([email protected]) on 2017-07-05T19:28:23Z No. of bitstreams: 2 Dissertação - Ghunter Paulo Viajante - 2009.pdf: 4054510 bytes, checksum: 7a7664ef1ea06fe7cc1052791f2fb337 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Cláudia Bueno ([email protected]) on 2017-07-07T19:26:47Z (GMT) No. of bitstreams: 2 Dissertação - Ghunter Paulo Viajante - 2009.pdf: 4054510 bytes, checksum: 7a7664ef1ea06fe7cc1052791f2fb337 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2017-07-07T19:26:47Z (GMT). No. of bitstreams: 2 Dissertação - Ghunter Paulo Viajante - 2009.pdf: 4054510 bytes, checksum: 7a7664ef1ea06fe7cc1052791f2fb337 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2009-06-02This work presents the project, construction and automation of a test bench for single-phase induction motor, up to 1 CV, based on a Brazilian Standard, ABNT 5383- 2/2007. In order to reach this purpose, theoretical studies on data acquisition systems, virtual instrumentation, industrial communication protocols and normalized testing methodologies are performed. After test bench construction, tests based on the Brazilian Standard are performed, in order to test a single-phase induction motor with starting capacitor .The tests results are presented.Este trabalho apresenta o projeto, implementação e automação de uma bancada para ensaios de motores de indução monofásicos de potência até 1 CV baseados na norma brasileira ABNT 5383-2/2007. Para tanto, foram realizados estudos teóricos acerca de sistemas de aquisição de dados, instrumentação virtual, protocolos de comunicação industrial e as metodologias de ensaios apresentadas na norma. Após a construção da bancada foram realizados os principais testes contemplados na norma brasileira em um motor de indução monofásico com capacitor de partida e apresentados os resultados

Energy Efficiency and Distributed Generation: A Case Study Applied in Public Institutions of Higher Education

This study focused on developing a sustainability project carried out in 11 Federal Institute of Education, Science, and Technology of Goiás (IFG) campuses wherein energy efficiency and distributed generation actions were developed. Energy consumption was optimized by retrofitting the lighting system, installing a photovoltaic (PV) generation system, quantifying the building efficiency, energy monitoring, training, and qualification, and focusing on the efficient use of electric energy. We first present the Brazilian legislation that regulates the Research and Development Program in the electric energy sector. Then, we describe the case study that was applied to the educational institution. In the lighting system, 18,377 inefficient lamps were replaced by lamps with more efficient technology, with an energy saving of 867.9 MWh/year and a peak demand reduction of 309.6 kW. The proposed generation system aimed to install 3076 PV modules on the roofs of selected campus buildings, totaling 1 MWp of installed power with an average annual power generation of 1736.9 MWh/year. The total project investment was USD 1,348,768.50 and the overall cost–benefit ratio of the project was 0.68, which will result in annual savings of approximately USD 197,321.85. This corresponded to a 58% reduction in energy bills. The project proposed in this work was considered technically and economically viable within the scope of the Brazilian Energy Efficiency Program

Energy Efficiency and Distributed Generation: A Case Study Applied in Public Institutions of Higher Education

This study focused on developing a sustainability project carried out in 11 Federal Institute of Education, Science, and Technology of Goiás (IFG) campuses wherein energy efficiency and distributed generation actions were developed. Energy consumption was optimized by retrofitting the lighting system, installing a photovoltaic (PV) generation system, quantifying the building efficiency, energy monitoring, training, and qualification, and focusing on the efficient use of electric energy. We first present the Brazilian legislation that regulates the Research and Development Program in the electric energy sector. Then, we describe the case study that was applied to the educational institution. In the lighting system, 18,377 inefficient lamps were replaced by lamps with more efficient technology, with an energy saving of 867.9 MWh/year and a peak demand reduction of 309.6 kW. The proposed generation system aimed to install 3076 PV modules on the roofs of selected campus buildings, totaling 1 MWp of installed power with an average annual power generation of 1736.9 MWh/year. The total project investment was USD 1,348,768.50 and the overall cost–benefit ratio of the project was 0.68, which will result in annual savings of approximately USD 197,321.85. This corresponded to a 58% reduction in energy bills. The project proposed in this work was considered technically and economically viable within the scope of the Brazilian Energy Efficiency Program

Effects of

Endotoxins from Bacillus thuringiensis (Bt) produced in transgenic pest-resistant Bt crops are generally not toxic to predatory and parasitic arthropods. However, elimination of Bt-susceptible prey and hosts in Bt crops could reduce predator and parasitoid abundance and thereby disrupt biological control of other herbivorous pests. Here we report results of a field study evaluating the effects of Bt sprays on non-target terrestrial herbivore and natural enemy assemblages from three rice (Oryza sativa L.) fields on Luzon Island, Philippines. Because of restrictions on field-testing of transgenic rice, Bt sprays were used to remove foliage-feeding lepidopteran larvae that would be targeted by Bt rice. Data from a 546-taxa Philippines-wide food web, matched abundance plots, species accumulation curves, time-series analysis, and ecostatistical tests for species richness and ranked abundance were used to compare different subsets of non-target herbivores, predators, and parasitoids in Bt sprayed and water-sprayed (control) plots. For whole communities of terrestrial predators and parasitoids, Bt sprays altered parasitoid richness in 3 of 3 sites and predator richness in 1 of 3 sites, as measured by rarefaction (in half of these cases, richness was greater in Bt plots), while Spearman tests on ranked abundances showed that correlations, although significantly positive between all treatment pairs, were stronger for predators than for parasitoids, suggesting that parasitoid complexes may have been more sensitive than predators to the effects of Bt sprays. Species accumulation curves and time-series analyses of population trends revealed no evidence that Bt sprays altered the overall buildup of predator or parasitoid communities or population trajectories of non-target herbivores (planthoppers and leafhoppers) nor was evidence found for bottom-up effects in total abundances of non-target species identified in the food web from the addition of spores in the Bt spray formulation. When the same methods were applied to natural enemies (predators and parasitoids) of foliage-feeding lepidopteran and non-lepidopteran (homopteran, hemipteran and dipteran) herbivores, significant differences between treatments were detected in 7 of 12 cases. However, no treatment differences were found in mean abundances of these natural enemies, either in time-series plots or in total (seasonal) abundance. Analysis of guild-level trajectories revealed population behavior and treatment differences that could not be predicted in whole-community studies of predators and parasitoids. A more conclusive test of the impact of Bt rice will require field experiments with transgenic plants, conducted in a range of Asian environments, and over multiple cropping seasons