Fernando de Souza Costa

Biomass fire consumption and carbon release rates of rainforest-clearing experiments conducted in northern Mato Grosso, Brazil

Biomass consumption and carbon release rates during the process of forest clearing by fire in five test plots are presented and discussed. The experiments were conducted at the Caiabi Farm, near the town of Alta Floresta, state of Mato Grosso, Brazil, in five square plots of 1 ha each, designated A, B, C, D, and E, with different locations and timing of fire. Plot A was located in the interface with a pasture, with three edges bordering on the forest, and was cut and burned in 1997. Plots B, C, D, and E were located inside the forest. Plot B was cut and burned in 1997. Plot C was inside a deforested 9-ha area, which was cut and burned in 1998. Plot D was inside a deforested 4-ha area, which was cut in 1998 and burned in 1999. Plot E was inside a deforested 4-ha area, which was cut and burned in 1999. Biomass consumption was 22.7%, 19.5%, 47.5%, 61.5%, and 41.8%, for A, B, C, D, and E, respectively. The effects of an extended curing period and of increasing the deforested area surrounding the plots could be clearly observed. The consumption, for areas cut and burned during the same year, tended toward a value of nearly 50% when presented as a function of the total area burned. The aboveground biomass of the test site and the amount of carbon before the fire were 496 Mg ha−1 and 138 Mg ha−1, respectively. Considering that the biomass that remains unburned keeps about the same average carbon content of fresh biomass, which is supported by the fact that the unburned material consists mainly of large logs, and considering the value of 50% for consumption, the amount of carbon released to the atmosphere as gases was 69 Mg ha−1. The amounts of CO2 and CO released to the atmosphere by the burning process were then estimated as 228 Mg ha−1 and 15.9 Mg ha−1, respectively. Observations on fire propagation and general features of the slash burnings in the test areas complete the paper.

Preliminary analysis of hybrid rockets for launching nanosats into LEO

This work determines the preliminary mass distribution of hybrid rockets using 98% H2O2 and solid paraffin mixed with aluminum as propellants. An iterative process is used tocalculate the rocket performance characteristics and to determine the inert mass fractionfrom given initial conditions. It is considered a mission to place a 20 kg payload into a 300 km circular equatorial orbit by air launched and ground launched hybrid rockets usingthree stages. The results indicate total initial masses of about 7800 kg for a groundlaunched hybrid rocket and 4700 kg for an air launched hybrid rocket.