Ana Flávia Neves Mendes Castro

Potencial energético da madeira de Eucalyptus sp. em função da idade e de diferentes materiais genéticos

The present study aimed to determine the influence of age and different genetic material of Eucalyptus sp. in wood energy production. Therefore, we evaluated three Eucalyptus sp. clones from Gerdau S/A, at four different ages: 3, 4, 5 and 7 years. Five discs were removed from each tree (0%, 25%, 50%, 75%, 100% of the trunk commercial height), and the wood basic density and calorific value were determined. Based on these values we estimated the energy m-3 amount. We observed an effect of age and genetic material for the wood density and the calorific value. Moreover, the amount of energy m-3 increased with increasing age, and the three genetic materials evaluated were significantly different between them. The GG 680 clone showed better performance for this variable, presenting at seven years 2,943 kW.h.m -³ . Note that the selection of the best genetic material must consider the wood technological characteristics, as well as their productivity and effectiveness of technical production.

Potencial energético da madeira de espécies oriundas de plano de manejo florestal no Estado do Rio Grande do Norte

The objective was to evaluate the energy potential of woods of species under forest management plan from Serido region in the Rio Grande do Norte state. It was used the wood species Jurema Preta, Pereiro, Marmeleiro, Catingueira, Mororo, Imburana, Jurema Branca and Mofumbo, at 20 years old, originated from the Dominga´s farm in the Caico/RN municipality. The density, the content of volatiles, the ash and fixed carbon, calorific value, elemental composition and carbon/nitrogen (C/N) and carbon/ hydrogen (C/H) analysis were carried out in the wood. Additionally, the amount of energy produced in kW.h.m-3 and kW.h.ha-1 for all species was estimated. The experiment was conducted in a completely randomized design with eight treatments (species), four replicates (sample trees), adding up to 32 sampling units. There were significant differences, at 5% significance between treatments for all variables, except for hydrogen percentage and C/H ratio. It was concluded that Mororo´s wood shows high energy potential, and along with Jurema Preta, presents higher energy generation per m3, and provides greater economy for the same productivity. The energy potential Jurema Preta wood´s stands out among the species. Pereiro´s wood stands for energy production per hectare. Marmeleiro and Jurema Branca´s woods are indicated as direct burning potential and Imburana´s wood is not recommended for power generation.

Estudo da decomposição térmica da madeira de oito espécies da região do Seridó, Rio Grande do Norte

RESUMO – Este trabalho teve como objetivo avaliar o perfil de decomposicao termica da madeira de oito especies utilizando as tecnicas de termogravimetria (TGA) e calorimetria diferencial exploratoria (DSC), bem como a consistencia desses metodos para decidir quais especies devem ser indicadas para producao de energia e carvao vegetal, comparando-os com os rendimentos gravimetricos da carbonizacao obtidos a partir de carbonizacoes em mufla de laboratorio. Para as analises por TGA e DSC, amostras de serragem foram aquecidas a taxa de 10 °C min -1 , sob atmosfera de nitrogenio, em vazao de 50 ml min -1 ate a temperatura final de 600 °C. Foram

Parâmetros cinéticos de adesivos produzidos a partir de taninos de Anadenanthera peregrina e Eucalyptus grandis

Due to the petroleum crisis in the Seventies, research had the objective of replace part or the entire conventional adhesive, based on petroleum. One way of replacement was the use of natural sources, as the tannins from some species of tree. However, the tannins present some use limitations, which can be overcome by sulfitation and acid hydrolysis. Therefore, the purpose of this study was evaluate the effect of tannina cid hydrolysis and sulfitation, extracted from the bark of Eucalyptus grandis and Anadenanthera peregrina in the kinetic parameters of tannin adhesives using the technique of differential scanning calorimetry (DSC). The tannins were hydrolyzed with acetic acid or hydrochloric acid 10N, using three pH values and three reaction times. The sulfitation was performed in a 5% sodium sulfite solution, in three reaction times. The activation energy, enthalpy and cure temperature of the adhesive were reduced by hydrolysis and sulfitation of tannins, but showed broadband polymerization. The tannins reaction time had no effect on the kinetic parameters.

Cobertura retrátil no crescimento de mudas clonais de eucalipto

O sucesso na implantacao de povoamentos florestais depende, em grande parte, do desempenho das mudas em resposta as variacoes no ambiente do viveiro. Objetivou-se, neste trabalho, avaliar o crescimento e a qualidade de mudas clonais de eucalipto em resposta a utilizacao de cobertura retratil nos canteiros de crescimento. O experimento foi conduzido no periodo de abril a julho de 2008, constituindo-se de um delineamento inteiramente casualizado em esquema fatorial 2 x 6, em dois ambientes (com cobertura retratil e sem cobertura retratil) e seis diferentes materiais geneticos. Foram avaliadas as caracteristicas altura da parte aerea, diâmetro do colo e pesos de materia seca de raizes, parte aerea e total das mudas. Os resultados indicaram que a utilizacao de cobertura retratil influenciou positivamente no crescimento de mudas clonais de eucalipto, as quais exibiram maiores medias de altura e incremento em biomassa de raizes e total para a maioria dos clones testados, o que contribuiu para o desenvolvimento das plantas, que apresentaram qualidade satisfatoria aos 55 dias.