Performance improvement of a diesel generating set with fuzzy control for stand-alone and grid-connected operations.

This paper proposes a management strategy for\ud a diesel generating set (GS) covering the mechanical part of\ud the system which includes speed and active power control,\ud the electrical part of the system which includes voltage\ud and reactive power control, and the synchronism with the\ud grid. The management is based on a fuzzy PD+I controller\ud structure which uses a fixed controller surface for all fuzzy\ud controllers (FCs). Simulations results for both stand-alone and\ud grid-connected operations using fuzzy controllers were superior\ud when compared to commercial methods (CM).FAPESP-2011/02170-

Genomic history of coastal societies from eastern South America

Sambaqui (shellmound) societies are among the most intriguing archaeological phenomena in pre-colonial South America, extending from approximately 8,000 to 1,000 years before present (yr bp) across 3,000 km on the Atlantic coast. However, little is known about their connection to early Holocene hunter-gatherers, how this may have contributed to different historical pathways and the processes through which late Holocene ceramists came to rule the coast shortly before European contact. To contribute to our understanding of the population history of indigenous societies on the eastern coast of South America, we produced genome-wide data from 34 ancient individuals as early as 10,000 yr bp from four different regions in Brazil. Early Holocene hunter-gatherers were found to lack shared genetic drift among themselves and with later populations from eastern South America, suggesting that they derived from a common radiation and did not contribute substantially to later coastal groups. Our analyses show genetic heterogeneity among contemporaneous Sambaqui groups from the southeastern and southern Brazilian coast, contrary to the similarity expressed in the archaeological record. The complex history of intercultural contact between inland horticulturists and coastal populations becomes genetically evident during the final horizon of Sambaqui societies, from around 2,200 yr bp, corroborating evidence of cultural change

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Management system for charging and discharging of batteries (lead acid) and search for the maximum power point generated on photovoltaic panels employed in distributed generation systems

O presente trabalho visa o desenvolvimento de um sistema de carga e descarga de baterias de chumbo-ácido para sistemas de geração distribuída acoplada a um conjunto de painéis fotovoltaicos e conectada à rede elétrica. O conjunto de painéis opera de forma a maximizar a energia gerada através de um algoritmo MPPT (Maximum Power Point Tracking) e a rede elétrica opera como rota para o excedente produzido pelos painéis. Para que a bateria possa ser carregada e descarregada com eficiência evitando sobrecargas e descarregamentos profundos, uma metodologia de estimação do estado de carga da bateria é implementada visando um controle mais eficiente (maximizando a vida útil da bateria) e um melhor aproveitamento da energia armazenada. Para o gerenciamento da carga e descarga do banco de baterias é utilizada uma topologia bidirecional (Boost-Buck) com controlador fuzzy P+I para estabilização de corrente ou tensão. Em relação à técnica de controle para o sistema PV, um controlador PI clássico é utilizado para regular a tensão terminal e ponto de máxima potência que é definido por um algoritmo de perturbação e observação (P&O). Para validar os controladores e os modelos teóricos desenvolvidos é construído um protótipo do sistema. São analisados, também, o comportamento do sistema de carga das baterias e painel fotovoltaico sob condições extremas como queda abrupta de irradiação solar, desconexão inesperada dos painéis e mudanças no ponto ótimo de funcionamento dos mesmos.The present work aims to develop a system of charging and discharging lead-acid batteries for distributed generation connected to a set of photovoltaic panels, and used in grid connected applications. The set of panels operates to maximize the energy produced by means of an MPPT (Maximum Power Point Tracking) algorithm and the power grid absorbs the extra power produced by the panels. For charging and discharging the battery pack and to prevent overload and deep discharge, a methodology for estimating the state of charge is implemented in order to obtain an efficient control technique (maximizing battery life), and more efficient use of the stored energy. To manage the charging and discharging of the battery bank a bidirectional topology (Boost-Buck) with fuzzy P+I controller for stabilization of current or voltage is used. To regards the PV control technique, a classical PI controller is employed to regulate the PV terminal voltage, and the maximum power point is determined by a perturb and observe (P&O) algorithm. To validate the controllers and the theoretical models developed is built a prototype system, and analyzed the behavior of the batteries charger and photovoltaic panel under extreme environmental conditions such as abrupt decrease of solar irradiation, unexpected panels disconnection and changes of the maximum power point of the panels

Energy management for integration of alternative sources and composite storage system connected to the grid

Esta tese de doutorado visa o estudo e o desenvolvimento de topologias e técnicas de controle para a integração de fontes alternativas tais como, solar e eólica acopladas a um barramento comum em corrente continua (CC) e conectá-las à rede de distribuição. O sistema contará também com elementos armazenadores como bancos de baterias e ultracapacitores, formando assim uma estrutura híbrida de armazenamento. Algoritmos de gerenciamento de energia serão implementados para que o perfil de injeção de potência na rede seja suave, eliminando as oscilações que são criadas, naturalmente, por fontes dependentes de fatores climáticos. Como consequência, os sistemas formados por fontes alternativas podem se tornar confiáveis e previsíveis, melhorando a capacidade de planejamento em um cenário cujos sistemas apresentem uma participação elevada na matriz energética. Duas metodologias de gerenciamento de energia são executadas neste trabalho, na primeira o ultracapacitor é gerenciado de modo a permitir a transferência de potência constante para a rede de distribuição em intervalos da ordem de minutos. A segunda estratégia se baseia no uso de banco de baterias combinado com ultracapacitores, formando uma estrutura híbrida de armazenamento. Nessa estrutura de gerenciamento, os armazenadores se comunicam entre si de forma a realizar um compartilhamento e filtragem de energia, fazendo com que transitórios de potência não sejam transmitidos para a rede de distribuição. Nesta estratégia, as baterias são responsáveis pelo fornecimento/absorção da potência média enquanto os ultracapacitores se encarregam dos transitórios. No segundo instante outras duas metodologias de divisão de carga são propostas para microrredes híbridas, contudo são baseadas em estratégias descentralizadas, ou seja, os armazenadores não se comunicam entre si para realizar o compartilhamento. Resultados experimentais e simulações irão comprovar a efetividade das metodologias de gerenciamento propostas.This Ph.D. dissertation aims the study and development of topologies and control techniques to integrate various alternative sources such as solar and wind, coupled to a direct current (DC) common bus and connect them to the distribution grid. Storage devices such as battery banks and ultracapacitors will form a hybrid storage structure that is responsible for the power supplying in periods in which the sources are unable (times of the day in which the light incidence is low or when the wind amount is scarce). Power management algorithms will be implemented so the alternative sources and storage devices exchange energy, in order to make smoother the power injection profile in the grid, eliminating the fluctuations that are created naturally by alternative sources. With a smooth power profile, energy management systems based on alternative sources may become more reliable and predictable, improving planning capacity in a scenario in which the renewable energy sources have a high penetration in the energy matrix. To obtain such a result, two power management methodologies are executed; the first one is based on ultracapacitors and aims to deliver constant power to the distribution network, even when the power production is zero. However, this technique allows constant power just for a few minutes, once the ultracapacitor capacity is limited. The second strategy is based on the bank of batteries combined with ultracapacitors, forming the hybrid storage system. In this management structure, the storage devices communicate with each other in order to perform a power sharing, resulting in a filtrated power profile delivered to the distribution network. In this strategy, the batteries are responsible to providing average power while ultracapacitors are in-charge of the transient power, sparing the batteries from supplying power peaks. In a second moment, two other load sharing methodologies are proposed for hybrid systems, but are based on decentralized techniques, i.e. storage devices do not communicate with each other to make the power sharing. Experimental and simulated results will prove the effectiveness of the control strategies and management methodologies

Model, design and implementation of LCC converter for power generation and distributed generation.

This paper proposes to model, design and implement a LCC (Line Commuted Converter) for power generation purpose, using alternative sources such as photovoltaic panel (PV), fuel cell and permanent magnet synchronous machine as the main power source. The converter is built with a full bridge twelve-pulse thyristor topology and connected to the alternative source through a line reactor. In order to extract maximum power from the sources, a classical maximum power point tracking algorithm (MPPT P&O) is applied. To validate the theoretical and simulated analysis, a 600 W experimental setup was built and controlled in closed loop. For the experimental results, the alternative source was represented by a variable DC power source in series with a resistor, making it possible to create controlled power steps and power events. During the operation, the grid current is analyzed in terms of power quality and an islanding event was created to analyze the converter?s behavior under critical conditions. All the experimental results show perfect conformity with the theory and simulation, proving the effectiveness of this converter topology for this purpose