Unified three-port topology integrating a renewable and an energy storage system with the grid-interface operating as active power filter

This paper presents the experimental validation of a unified three-port topology, integrating a renewable energy source (RES) and an energy storage system (ESS) (or an electric vehicle) with the grid-interface operating as active power filter (APF). The proposed topology is based on a three-phase grid-interface (whose role is to operate as a APF grid-tied inverter capable of compensating current harmonics, imbalanced currents and low power factor), on a RES-interface for solar photovoltaic (PV) panels (whose role is to extract the maximum power from the PV panels), and on an ESS-interface for batteries (whose role is to store/inject energy according to the power management of the electrical installation). The paper presents the control algorithms for each interface within the scope of the different operation modes allowed by the unified three-port topology. Simulation and experimental results are presented in order to validate the distinguishing aspects of the proposed unified three-port topology.This work has been supported by FCT – Fundação para a Ciência e Tecnologia with-in the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project SAICTPAC/0004/2015 – POCI – 01– 0145–FEDER–016434. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT

A novel topology of multilevel bidirectional and symmetrical split-Pi converter

The paradigm of smart grids has encouraged new developments of power electronics converters, for instance, in the perspective of renewables and electric mobility applications. Aligned with this perspective, this paper proposes a novel topology of a multilevel bidirectional and symmetrical (MBS) split-pi dc-dc converter. As a central distinguishing feature, it operates with three voltage levels in both dc sides (0, vdc/2, vdc), meaning that the voltage stress in each semiconductor is reduced when compared with the conventional split-pi converters, and it operates with controlled variables (voltage and current) based on the interleaved principle of operation, although it is not an interleaved split-pi converter. As demonstrated along the paper, the MBS split-pi converter can be controlled with current or voltage feedback in any of the dc interfaces, while the common dc-link voltage is controlled by the dc interface where the source is connected. The adopted current and voltage control schemes, as well as the pulse-width modulation, are presented and comprehensively explained. The validation is presented for the main operation modes, where it is possible to verify the claimed distinguishing features of the proposed MBS split-pi converter.Fundação para a Ciência e Tecnologia (FCT

Radioatividade: uma lacuna na formação dos licenciando do IQ/UnB

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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

ATLANTIC-PRIMATES: a dataset of communities and occurrences of primates in the Atlantic Forests of South America

Primates play an important role in ecosystem functioning and offer critical insights into human evolution, biology, behavior, and emerging infectious diseases. There are 26 primate species in the Atlantic Forests of South America, 19 of them endemic. We compiled a dataset of 5,472 georeferenced locations of 26 native and 1 introduced primate species, as hybrids in the genera Callithrix and Alouatta. The dataset includes 700 primate communities, 8,121 single species occurrences and 714 estimates of primate population sizes, covering most natural forest types of the tropical and subtropical Atlantic Forest of Brazil, Paraguay and Argentina and some other biomes. On average, primate communities of the Atlantic Forest harbor 2 ± 1 species (range = 1–6). However, about 40% of primate communities contain only one species. Alouatta guariba (N = 2,188 records) and Sapajus nigritus (N = 1,127) were the species with the most records. Callicebus barbarabrownae (N = 35), Leontopithecus caissara (N = 38), and Sapajus libidinosus (N = 41) were the species with the least records. Recorded primate densities varied from 0.004 individuals/km 2 (Alouatta guariba at Fragmento do Bugre, Paraná, Brazil) to 400 individuals/km 2 (Alouatta caraya in Santiago, Rio Grande do Sul, Brazil). Our dataset reflects disparity between the numerous primate census conducted in the Atlantic Forest, in contrast to the scarcity of estimates of population sizes and densities. With these data, researchers can develop different macroecological and regional level studies, focusing on communities, populations, species co-occurrence and distribution patterns. Moreover, the data can also be used to assess the consequences of fragmentation, defaunation, and disease outbreaks on different ecological processes, such as trophic cascades, species invasion or extinction, and community dynamics. There are no copyright restrictions. Please cite this Data Paper when the data are used in publications. We also request that researchers and teachers inform us of how they are using the data. © 2018 by the The Authors. Ecology © 2018 The Ecological Society of Americ