Lívia Cássia Viana

Evaluation of the energy-related properties of tropical wood waste using NIR spectroscopy

The aim of this study was to evaluate the energy-related potential of wood residues of four Amazonian species and calibrate the properties of wood and charcoal using the Near Infrared Spectrometry (NIRS) technique. Residue slabs of cardeiro (Scleronema micranthum Ducke), cedrinho (Scleronema sp.), louro (Ocotea sp.), and piquiarana (Caryocar villosum Pers.) wood were used. The following properties were determined: density, chemical composition, immediate chemical analysis, and superior calorific value of wood; and yield, immediate chemical analysis, calorific value, and friability of charcoal. NIR spectra were obtained and calibration models were generated for each energy property. The results indicate that residues of these forest species can be used as a renewable energy source. NIR spectroscopy has proved to be a possible tool for calibrating energy properties of wood.

Avaliação das Propriedades Energéticas de Resíduos de Madeiras Tropicais com Uso da Espectroscopia NIR / Evaluation of the Energy-related Properties of Tropical Wood Waste Using NIR Spectroscopy

The aim of this study was to evaluate the energy-related potential of wood residues of four Amazonian species and calibrate the properties of wood and charcoal using the Near Infrared Spectrometry (NIRS) technique. Residue slabs of cardeiro (Scleronema micranthum Ducke), cedrinho (Scleronema sp.), louro (Ocotea sp.), and piquiarana (Caryocar villosum Pers.) wood were used. The following properties were determined: density, chemical composition, immediate chemical analysis, and superior calorific value of wood; and yield, immediate chemical analysis, calorific value, and friability of charcoal. NIR spectra were obtained and calibration models were generated for each energy property. The results indicate that residues of these forest species can be used as a renewable energy source. NIR spectroscopy has proved to be a possible tool for calibrating energy properties of wood.

Fundamentos e estado da arte da espectroscopia no infravermelho próximo no setor de base florestal

O conhecimento das propriedades da madeira e de fundamental importância para indicacao dos potenciais de utilizacao final deste material. Na busca por novas alternativas para caracterizacao rapida, simples e confiavel, destacam-se as avaliacoes nao destrutivas da madeira. A espectroscopia no infravermelho proximo (NIRS) vem sendo utilizada como metodo nao destrutivo que permite obter informacoes qualitativas e quantitativas dos constituintes da biomassa atraves da interacao das ondas eletromagneticas do infravermelho proximo com a amostra. Este trabalho tem como objetivo fornecer uma revisao sobre a tecnica da espectroscopia no infravermelho proximo e sua aplicacao no setor florestal. A tecnica esta presente em praticamente todas as areas, devido ao nivel de desenvolvimento que esta tecnologia atingiu nos ultimos anos. A espectroscopia NIR tem se mostrado uma ferramenta rapida e eficiente para substituicao dos diversos ensaios que determinam a qualidade da madeira.

NIR SPECTROSCOPY CAN EVALUATE THE CRYSTALLINITY AND THE TENSILE AND BURST STRENGTHS OF NANOCELLULOSIC FILMS

The near infrared (NIR) spectroscopy presents itself as an interesting non-destructive test tool as it enables a fast, simple and reliable way for characterizing large samplings of biological materials in a short period of time. This work aimed to establish multivariate models to estimate the crystallinity indices and tensile and burst strength of cellulosic and nanocellulosic films through NIR spectroscopy. NIR spectra were recorded from the films before tensile and bursting strength, and crystallinity tests. Spectral information were correlated with reference values obtained by laboratory procedures through partial least square regression (PLS-R). The PLS-R model for estimating the crystallinity index presented a coefficient of determination in cross-validation (R2cv) of 0,94 and the ratio of performance to deviation (RPD) was 3,77. The mechanical properties of the films presented a high correlation with the NIR spectra: R2p = 0,85 (RPD = 2,23) for tensile and R2p = 0,93 (RPD = 3,40) for burst strength. The statistics associated to the models presented have shown that the NIR spectroscopy has the potential to estimate the crystallinity index and resistance properties of cellulose and nanocellulose films on in-line monitoring systems.

Production of plywood panels from Pinus taeda using veneers of differing densities and phenol-formaldehyde resin with high and low molecular weights

This study aimed to evaluate the bonding quality of plywood panels from Pinus taeda using low and high molecular weight phenol-formaldehyde resin and veneers from three different density classes. The experiment consisted of six treatments, each of which produced three panels (replicates). Tests were conducted to evaluate glue line strength to shear stress after two boiling cycles and after 24 hours of cold water immersion. Also determined was the percentage of defects in wood samples. Results indicated that the density classes being assessed differed statistically. However, no significant difference was found between panels produced with high and panels produced with low molecular weight resin as to the mean values of glue line strength, whether subjecting them to two boiling cycles or after 24 hours of cold water immersion. Interactions between different density classes and adhesive formulations were found not significant either. Low molecular weight resin (BPM) and panels produced with higher density veneers were found to have better behavior, regarding both bonding strength and percentage of defects. It was concluded that the bonding quality of plywood panels from Pinus taeda was satisfactory after using different densities of veneer and also high and low molecular weight phenolic resins. All treatments were found to comply with minimum requirements established in European standard EN 314-1/1993, which addresses bonding quality of plywood panels.