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The periodic supply vessel planning problem (PSVPP) consists in determining a periodic schedule and the respective fleet composition for servicing offshore units on a regular basis. One of the challenges for the PSVPP is determining reliable schedules with a good compromise between reliability and cost. This work extends the PSVPP by including stochastic demand and travel time. We also introduce a novel methodology based on a voyage‐based model to deal with the schedule robustness. Basically, key statistical parameters related to the routes' demand and execution time are generated. They are used together with a set of probability combinations to incorporate the schedule reliability into the optimization model. Therefore, schedule reliability is an input parameter in the optimization model. The instances used in the study are based on real data from Brazil. A comparison of the new methodology to conventional approaches is presented, and a Monte Carlo simulation is used to evaluate the quality of the solutions. The proposed methodology is able to generate robust schedules at a lower cost compared to the conventional approaches. The proposed methodology might be applied to other stochastic problems, where schedule reliability is a key parameter for the problem. [ABSTRACT FROM AUTHOR]

The Generation Expansion Planning (GEP) process in Brazil involves computational models with a range of variables and constraints inherent in a mostly hydrothermal system. Such models generally use technical and economic parameters to represent the system, but with the growing concern about environmental and climatic issues, the need has arisen for environmental parameter analysis to promote a better representation of a more comprehensive optimum. In view of the recent Paris Agreement, through which the Brazilian government committed itself to significantly reduce its greenhouse gas emissions (GHG) by 2030, it has become essential that the GEP take into account the emission of gases. In this work, scenarios that penalize or limit the emission of greenhouse gases are created and compared inside the existent Investment Decision Model (MDI) used in Brazil. The main objective is to verify how the objective of reducing emissions would change the optimum expansion planning originally provided by the investment model. The results show that within the created scenarios, the largest reduction is achieved when considering a monetary penalty of US$ 25.00/tCO 2eq in the burning of fossil fuels for power generation. In this case, to reduce the emissions, the investment model chooses a larger expansion of wind and biomass sources with a corresponding raise in the cost of approximately 5.3%, allowing a total reduction of about 39 MtCO 2eq in relation to the reference scenario at the end of the planning horizon. • Hydrothermal Generation Expansion Planning with environmental ex-ternalities. • Scenarios that penalize or limit the emission of greenhouse gases are simulated. • The internalization of environmental externalities defines environmen-tal policies. • GHG emissions reductions can change the optimum expansion plan-ning. • A larger expansion of wind and biomass sources with a raise of 5.3% of the cost. [ABSTRACT FROM AUTHOR]

On November 5th, 2015, the Fundão dam rupture released >50 million m 3 of ore tailings into the Doce River, Minas Gerais State, Brazil. The huge volume of mud spread along the river and reached the sea, 17 days after the disaster, in Regência, Espírito Santo State (ES). In 2018, after three years of the disaster, the impacts of the ore tailings in the marine environment are still unclear. This study aims to investigate possible short-term impacts in marine biodiversity caused by the ore tailings' mud over the reef ecosystems that are closest to the disaster area: i.e. recently discovered reefs in the southern Abrolhos Bank. A remote sensing surveillance including winds, sea surface temperature, total suspended material and watercolor (MODIS Aqua data) indicated that the iron tailings plume reached the southern portion of Abrolhos Bank on June 16th, 2016. Subsequently, to obtain further evidence of the presence of the tailings in the coral reefs, water samples were collected in a gradient spanning from the river estuary to the reefs in southern Abrolhos Bank, we also analyzed the isotopic and microbial composition of the samples, as well as the reef benthic composition. Despite no clues of negative impact on benthic (coral) communities, isotopic analysis confirmed the presence of the plume over the reefs area. This study serves as a baseline for future long-term impact assessments of the health of coral reefs in the Abrolhos Bank., (Copyright © 2019 Elsevier B.V. All rights reserved.)