Eletrobras (Brazil)

Abstract. Accurate Land Use and Land Cover (LULC) maps support the analysis of land use dynamics and provide a scientific basis for land management around water reservoirs. In recent years, technological advancements have led to significant improvements in the methodological design of these mappings. In the context of large-scale Earth Observation (EO) data, satellite image time series (SITS) represent a powerful approach for capturing and measuring surface changes. This study aimed to map LULC in a contributing watershed of the Batalha Hydroelectric Power Plant reservoir, located in eastern Goiás, Brazil. We used the Sentinel-2/MSI time series from Brazil Data Cube (BDC) for the agricultural year (July 2022 to June 2023). The classification included ten classes: Forest Formations, Savanna Formations, Grass Formations, Silviculture, Pasture, Single-Cycle Agricultural Crops, Multi-Cycle Agricultural Crops, Edification, Seasonally Flooded Areas, and Water. We used the Random Forest algorithm and the best practices for assessing mapping accuracy. The results demonstrate the potential of SITS for mapping LULC conditions around water reservoirs. The LULC map generated provides valuable information for managing land use around the reservoir, with a focus on areas where seasonal slope exposure occurs along the immediate reservoir edge. Mapping these areas represents a significant gain in information, as it contributes to the monitoring of sites susceptible to mass movements and marginal erosion processes.

A shift towards a carbon-neutral generation matrix is underway worldwide. In Brazil, where long-term forward markets drive investments, this trend is not different. For instance, long-term contracted renewable generation investors face the so-called price-and-quantity risk, which materializes whenever a generator falls short of producing the contracted amount and has to purchase this deficit at high spot prices. Notwithstanding, some renewable sources exhibit relevant hourly complementary generation profiles, e.g., wind and solar in the Northeastern Region of Brazil, suggesting a synergy that can be explored through exchange mechanisms to mitigate the price-and-quantity risk. Therefore, in this work, we investigate a decentralized approach based on hourly swaps, i.e., the exchange of forward contracts with different delivery hours. With these new hedging instruments, renewable agents can adjust their current flat forward positions and modulate them according to their generation profile and risk aversion level, thus minimizing the exposure to price-and-quantity risk through a pure financial market mechanism. We evaluate the benefits of the proposed mechanism through market equilibria using real data from the Brazilian power system. Results provide relevant evidence that the proposed hedging instrument should be beneficial to market agents and even foster higher long-term forward involvements with lower risk levels.

Eles chegaram por último e com eles vieram, por curiosidade, alguns oficiais cristãos, que vieram ouvir o canto dramático e divino do Kol Nidrei. Os chefes de família mal se importavam com essa multidão heterogênea. Os fiéis das últimas fileiras, artesãos e carregadores, no entanto, ficaram encantados:

cuidado sade.

The search for solutions that reduce the environmental impact of construction has driven the development of new materials. Bio-concrete represents a significant advance, presenting itself as an alternative to traditional concrete. Recent studies point to durability in outdoor conditions as one of the main challenges in its application. This paper presents natural durability studies performed on bamboo bio-concrete, produced with a bamboo particle volume of 50%. A surface treatment of applying resin externally was tested to reduce water ingress during weathering. The bio-concretes were exposed to natural and outdoor weather conditions for twelve months, and meteorological records were collected during the study period. The effect and influence of the external resin was investigated using visual surface analysis, uniaxial compression, modulus of elasticity and scanning electron microscopy. In terms of visual aspects, the resin was not effective in preventing loss of gloss, while in terms of microstructure, these samples showed better adhesion between the bamboo particles in the matrix. The compressive strength showed significant reductions of 60% (stress) and 73% (Young’s modulus) after twelve months of weathering. External resin could improve microstructures from surfaces to internal portions and more effectively preserve the mechanical strength of bio-concrete.