Dispatchable High-Power Wind Turbine Based on a Multilevel Converter with Modular Structure and Hybrid Energy Storage Integration

This paper presents a new multilevel converter solution with modular structure and hybrid energy-storage integration suitable to drive modern/future high-power medium-voltage wind turbines. The hybrid energy-storage integration means that part of the converter submodules are built with batteries and part of them with conventional capacitors. Since traditional wind turbines are non-dispatchable generators, the integration of an energy storage system could be beneficial in multiple ways as the wind power plant could provide stability support to the grid, improvement of the unit commitment and economic dispatch, and the power plant owner could increase his revenues in the electricity market. The capacitors of the proposed converter are responsible to transfer the power produced by the wind turbine to the grid, and the batteries are only charged/discharged with the mismatch between the power produced by the turbine and the power to be injected into the grid, considering a dispatchable operation where the power injected into the grid is different from the power generated by the turbine. The medium-voltage structure could be an interesting option to overcome problems related to high currents in modern/future high-power wind turbines resulting in more efficient, more compact and lighter solutions. Modular multilevel converters are suitable to handle medium-voltage levels and they allow for a straightforward integration of energy storage systems in a decentralized manner

Strategies to enhance the productivity of rainfed off-season maize.

In Brazil, off-season rainfed maize is usually affected by limited water due to irregularities in rainfall. Alternatives to mitigate these effects include ground cover to reduce evaporation losses and the use of cultivars with a deeper rooting system. We conducted a study in Goias, Brazil, to evaluate the influence of different crop management strategies to mitigate the effect of limited water in maize yield. Modeling was used to simulate scenarios that consisted of 0, 3.5 and 5.0 t ha-1 of soybean residue left on the soil surface combined with cultivar ideotypes with 0.30 m, 0.50 m 0.70 m deep rooting system grown with 60 and 340 kg ha-1of nitrogen. The results showed that maintaining residue in the soil surface in combination with the use of cultivars with deeper rooting systems favored higher yields of off-season maize. Our results also indicated that a cultivar with rooting system in the top 0.50 m of the soil fertilized with a high nitrogen rate tended to be more efficient in the use of the soil available wate

Evolução da produtividade e produção de grãos no sistema de Integração Lavoura-Pecuária de corte da Embrapa Milho e Sorgo.

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Forrageiras para rotação de culturas na produção do milho em sistema Integração Lavoura-Pecuária na região Central de Minas Gerais.

O estado de Minas Gerais ocupa o primeiro lugar nacional na produção de grãos de milho na primeira safra agrícola e responde por 18% de toda produção nacional com base na média de 2021 e 2022 (IBGE, 2022). Na segunda safra agrícola, a classificação do Estado cai para o 5° lugar e contribui com 3% da produção nacional. Em termos de rendimento médio por hectare, na primeira safra, as lavouras de milho-grão de Minas Gerais estão em 5° lugar, com uma produtividade média de 7 t ha-¹, enquanto a média dos quatro primeiros estados produtores é de 9 t ha-¹ (DF, MS, GO, PR) (IBGE, 2022). Inúmeros fatores contribuem para a menor produtividade do milho em Minas Gerais, o primeiro deles é a dependência dos produtores por precipitação no cultivo da primeira safra agrícola. Esse fator ambiental tem se mostrado bastante variável e instável nos últimos anos. As datas de semeadura, de acordo com o ZARC (Zoneamento Agrícola de Risco Climático), para um menor risco e frustração na produção, indicam uma janela estreita, basicamente com semeadura no mês de outubro, inclusive para produção de silagem de milho (MELO et al., 2021). Outro fator importante, determinante para a menor produtividade, é a baixa fertilidade natural dos solos, os quais são caracterizados pela grande necessidade de aplicação de fertilizantes e corretivos (AMARAL et al., 2004).OD

Desempenho de novilhas Nelore e Nelore x Angus em sistema de Integração Lavoura-Pecuária da Embrapa Milho e Sorgo.

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Genetic diversity of Bromeliaceae species from the Atlantic Forest

ABSTRACT. The Bromeliaceae family includes a range of species used for many purposes, including ornamental use and use as food, medicine, feed, and fiber. The state of Espírito Santo, Brazil is a center of diversity for this family in the Atlantic Forest. We evaluated the genetic diversity of five populations of the Bromeliaceae family, including specimens of the genera Aechmea, Billbergia (subfamily Bromelioideae), and Pitcairnia (subfamily Pitcairnioidea), all found in the Atlantic Forest and distributed in the state of Espírito Santo. The number of alleles per locus in populations ranged from two to six and the fixation index (F), estimated for some simple sequence repeats in bromeliad populations, was less than zero in all populations. All markers in the Pitcairnia flammea population were in Hardy-Weinberg equilibrium (P < 0.05). Moreover, significant deviations from Hardy-Weinberg equilibrium were observed at some loci in populations of the five bromeliad species. In most cases, this can be attributed to the presence of inbreeding or the Wahlund effect. The genetic diversity indices of five species showed greater allelic richness in P. flammea (3.55). Therefore, we provide useful information for the characterization of genetic diversity in natural populations of Aechmea ramosa, Aechmea nudicaulis, Billbergia horrid, Billbergia euphemia, and P. flammea in Atlantic Forest remnants in the south of Espírito Santo state

The branded and gendered Brazilian body: Material and symbolic constructions in an overlooked context

Since its first conference in 2006, CCT has been growing in size and reach. Some have noted that CCT has become much more European in the recent years, with North American and European countries taking turns to host the event