ABSTRACT Background: The wood heat treatment results in the partial degradation of its chemical constituents, mainly cellulose and hemicellulose, reducing the hygroscopicity of the material. This process improves the dimensional stability and resistance to biodeterioration and worsens the mechanical resistance. This work aimed to evaluate the effect of heat treatment on the physical, anatomical, chemical, and mechanical properties of Fraxinus excelsior wood. In untreated and heat-treated wood, the pH, buffering capacity, basic density, equilibrium moisture content, shrinkage, wood anatomy, thermogravimetric behavior, and chemistry by conventional and FTIR methods were determined. Results: Heat treated wood had lower pH (5.50), equilibrium moisture content (6.26%), shrinkage (7,29%), holocellulose contents (55,96%) and higher buffering capacity (0,479 mmol/L), extractives (8,25%), and lignin contents (35,78%). Heat treatment reduced the pH and increased the buffering capacity of the wood, reduced the holocellulose content, and increased the lignin content, leaving the wood less hygroscopic and reducing its volumetric and linear variation. The process did not change the basic density and fiber length, but it reduced their width, lumen diameter, and wall thickness. The FTIR analysis confirmed the degradation of holocellulose and division of aliphatic side chains in lignin. The maximum dredging range of untreated and heat-treated wood occurred at 350 ºC, and the heat-treated wood had a higher residual mass when subjected to 500 ºC. Conclusion: Heat-treated wood can be indicated for products used in external environments, such as floors, fences, coatings, door and window structures.

ABSTRACT Background: The aim of this study was to investigate near infrared (NIR) spectroscopy ability to estimate nanofibril concentration, physical and mechanical properties of Kraft paper reinforced with cellulose nanofibrils (CNF). For this purpose, paper sheets were prepared by mixing unbleached Eucalyptus fibers and cellulose nanofibrils. Twelve treatments result from the combination of the nominal grammages 75, 85, 95 and 105 g m-² with the nanofibril concentrations of 1, 5 and 10wt%, with 7 sheets per treatment. NIR spectra measured directly on paper specimens were correlated with physical and mechanical properties values obtained through conventional laboratory analyzes. Results: Principal component analysis (PCA) revealed no separation among specimens related to nanofibril content. Partial least squares regression (PLS-R) models for estimating nanofibril content, tensile index, stretch and resistance to air passage yielded R 2cv ranging from 0.73 to 0.98. Partial least squares - discriminant analysis (PLS-DA) correctly classified up to 93% of the paper specimens both by grammage and nanofibril content using NIR spectra. Conclusion: This approach appears to be suitable for predicting physical and mechanical properties of Kraft papers and can detect cellulose nanofibril content in the cellulose handsheets.

Abstract: Pyrolysis is a promising technology for thermal conversion of lignocellulosic biomasses into a higher added value fuel. The aim of this study was to analyze the potential of four agroforestry biomasses to produce energy as a raw material or as a bio-coal. In this study, slow pyrolysis was conducted in three final temperatures to evaluate the bio-coal production of four agroforestry biomasses widely available in Brazil. The biomasses used were sugarcane bagasse (Saccharum sp.), bamboo (Dendrocalamus giganteus), straw bean (Phaseolus vulgaris) and eucalypts wood chips (Eucalyptus sp.). In the first part was presented the raw biomasses proprieties, such as lignin, carbon, hydrogen and ash contents. In the second part was showed the bio-coal proprieties, such as gravimetric and fixed carbon yields, fixed carbon and ash contents. These bio-coal results were showed as a function of final temperature of pyrolysis. The best energy indicators for bio-coal production, such as fixed carbon yield, high heating value, was observed in the bamboo and eucalypts. The bagasse and straw bean biomasses have high concentrations of ash and low lignin content when compared with the other biomasses assessed and are less suitable to produce bio-coal.

Resumo A procura intensa por essências madeireiras nativas consolidadas, que apresentam elevado uso, pode ocasionar a superexploração de espécies e diminuição do seu estoque na floresta. Uma alternativa para essa situação é a substituição dessas espécies por outras com propriedades da madeira semelhantes e com suficiente estoque de crescimento na floresta. O objetivo deste trabalho foi agrupar as espécies da Amazônia através das propriedades físico-mecânicas da madeira e realizar a análise discriminante para identificar quais características tecnológicas são mais importantes para o agrupamento. As espécies estudadas foram provenientes de oito localidades distintas da região amazônica. As propriedades físico-mecânicas utilizadas obtidas da literatura especializada nacional foram: densidade básica, contração (tangencial, radial e volumétrica), flexão estática, compressão paralela e perpendicular às fibras, dureza Janka paralela e transversal, tração perpendicular às fibras, fendilhamento e cisalhamento. Foi utilizada a técnica de análise multivariada de Cluster (distância euclidiana simples e o método de Ward) e a análise discriminante para avaliar o agrupamento. A análise de Cluster foi eficiente para agrupar as espécies, que foram separadas em três grupos distintos. As espécies que se destacaram foram a Helicostylis pedunculata Benoist. e Tachigali chrysophylla (Poepp.) Zarucchi & Herend., por se agruparem com as espécies mais comercializadas. Os menores valores de Wilks’Lambda foram da densidade da madeira (0,759053), cisalhamento (0,802960) e compressão paralela às fibras (0,825594). Essas características foram as mais determinantes para discriminar os grupos. A análise de agrupamento é eficiente para indicar a substituição de espécies consolidadas na Amazônia.

Abstract The intense search for consolidated native wood essences, which are highly used, can lead to the overexploitation of species and decrease their stocks in the forest. An alternative to this situation is the replacement of these species by others with similar wood properties and with sufficient forest growing stock. The objective of this work was to cluster the Amazon species through wood physical-mechanical properties and perform the discriminant analysis to identify which technological characteristics are more important for the clustering. The species studied came from eight different locations in the Amazon region. The properties used were: basic density, contraction (tangential, radial and volumetric), static flexion, compression parallel and perpendicular to the fibers, Janka hardness parallel and transversal, traction perpendicular to the fibers, cracking and shearing, all obtained from the national specialized literature. Multivariate Cluster analysis (simple Euclidean distance and Ward’s method) and the discriminant analyses were used to evaluate the clustering. Cluster analysis was efficient to cluster the species, which were separated into three distinct groups. The species that stood out were Helicostylis pedunculata Benoist. and Tachigali chrysophylla (Poepp.) Zarucchi & Herend., f or clustering with the most commercialized species. The lowest values of Wilks’Lambda were wood density (0.759053), shearing (0.802960) and compression parallel to the fibers (0.825594). These characteristics were the most determinant to discriminate the clusters. The clustering analysis was efficient for the separation of the species into marketing clusters.

RESUMO Devido ao fato de a madeira in natura possuir características de permeabilidade inadequadas para algumas aplicações, diversas técnicas de processamento foram desenvolvidas, como tratamentos hidrotérmicos e congelamento, que visam melhorar essas propriedades. O objetivo deste estudo foi analisar os efeitos do tempo e da temperatura de tratamento na permeabilidade da madeira de Eucalyptus grandis. Foram utilizados amostras da região do cerne de três árvores de E. grandis, cada uma com as dimensões 30 x 8 x 3 (comprimento, largura, espessura). Os tratamentos foram realizados a três temperaturas (-20, 60 e 100 °C) e três tempos de exposição (5, 10 e 15 horas). Os tratamentos à -20 °C foram realizadas dentro de um freezer doméstico, enquanto os tratamentos à 60 e 100 °C em um reator Parr, onde as madeiras ficaram submersas em água. Foi observado a remoção dos extrativos apenas na superfície e interior de madeira tratada a 60 e 100 ° C; enquanto a permeabilidade aumentou para todas as condições de tratamento quando comparados à testemunha.

ABSTRACT Due to the fact that raw timber has permeability characteristics unsuitable for some applications, several processing techniques have been developed, such as hydrothermal treatments and freezing, which aim to improve these properties. The objective of this study was to analyze the effects of treatment temperature and duration on the permeability of Eucalyptus grandis wood. Heartwood samples from three E. grandis trees were utilized, each with the dimensions 30 x 8 x 3 (length, width, thickness). The treatments were carried out at three temperatures (-20°C, 60°C, and 100°C) and three exposure durations (5, 10, and 15 hours). Treatments at -20°C were conducted inside a domestic freezer, while treatments at 60°C and 100°C took place inside a Parr Reactor, while the wood being submerged in water. Extractive removal was only observed at the surface and interior of wood treated at 60°C and 100°C; while all treatment conditions increased permeability with respect to control treatments.

Abstract: Timber from the second cutting cycle may make up the majority of future crop volumetric. However, there are few studies of the physical and mechanical properties of this timber, which are important to support the consolidation of new species. This study aimed to use Artificial Neural Networks to estimate the physical and mechanical properties of wood from the Amazon, based on basic density. The properties were: shrinkage (tangential, radial and volumetric), static bending, parallel and perpendicular to the fiber compression, parallel and transverse to the fibers, Janka hardness, traction, splitting and shear. The estimate followed the tendency of the data observed for the tangential, radial and volumetric shrinkage. The network estimated the mechanical properties with significant accuracy. Distribution of errors, static bending, parallel compression and perpendicular to the fiber compression also showed significant accuracy. Artificial Neural Networks can be used to estimate the physical and mechanical properties of wood from Amazon species.

RESUMO Este trabalho teve como objetivo comparar duas metodologias de amostragem, a amostragem casual simples (ACS) e a amostragem casual estratificada (ACE), com o propósito de determinar o número ótimo de amostras de madeira em tora para obter o teor de umidade da população. Foram consideradas diferentes porcentagens de erro admissível (5, 10, 15 e 20%) para cada metodologia de amostragem. Na condução do trabalho foram amostradas aleatoriamente, de um lote de 250 st de madeira, 144 toras e distribuídas em quatro classes de diâmetro. Em seguida, determinou-se o teor de umidade dessas amostras, e a partir desses valores foram calculadas as estimativas populacionais (média, desvio-padrão, variância, coeficiente de variação e erro-padrão) pela ACS e pela ACE, determinando assim o número ótimo de toras (n) a serem amostradas nas diferentes porcentagens do erro admissível adotadas neste estudo, a 95% de probabilidade. De acordo com os resultados, o número de toras a serem amostradas pela ACS para cada erro admissível 5, 10, 15 e 20% foi, respectivamente, 214, 55, 25 e 14 toras; para a ACE (proporcional) foi 141, 35, 16 e 9; e para ACE (ótima) foi 136, 34, 15 e 8. Concluiu-se que o método de amostragem mais indicado para este estudo, considerando um mesmo erro admissível, foi a ACE.

ABSTRACT This study had the objective of comparing two methodologies of sampling, Simple Random Sampling (ACS) and Stratified Random Sampling (ACE) to determine the optimum number of roundwood samples to obtain the moisture content of the population. In order to achieve this goal, different percentages of allowable error (5,10,15 and 20%) were considered for each sampling methodology. In the conduction of this study, the samples were randomly taken from a lot of 250 steres of wood, 144 roundwood of three meters of length and distributed in four classes of diameter. Later, the moisture content of these samples was determined. And, from these values, the population estimates (average, standard deviation, variance, coefficient of variation, and standard error) by ACS and ACE methods, helped to determine the optimum number of roundwood (n) to be sampled from different percentages of allowable error adopted in this study at 95% probability. According to the results, the amount of roundwood to be sampled from ACS for each allowable error 5, 10, 15 and 20% was respectively 214, 55, 25 and 14. For the ACE (proportional allocation) the amount of roundwood was 141, 35, 16 and 9 for ACE (optimal allocation) this number was 136, 34, 15 and 8. It was concluded that the most indicated sampling method for this study, considering the allowable error, was the ACE method.

RESUMO A madeira, de modo geral, é um material com excelentes propriedades, mas ressalta-se que algumas características podem limitar o seu uso. Neste sentido, alguns métodos de tratamentos térmicos vêm surgindo como alternativa para melhorar algumas propriedades tecnológicas da madeira. Neste contexto, o objetivo do trabalho foi avaliar o efeito do tempo e da temperatura do tratamento hidrotérmico e do congelamento nas propriedades físicas e mecânicas da madeira de Eucalyptus grandis W.Hill ex Maiden. Foram utilizadas três árvores, selecionando-se apenas a madeira do cerne para obtenção dos corpos de prova de dimensões 30 x 8 x 3 cm (comprimento x largura x espessura). Os tratamentos foram realizados nas temperaturas de -20, 60 e 100 °C combinados a três tempos de exposição (5, 10 e 15 horas). O tratamento na temperatura de -20 °C foi realizado em um freezer doméstico, e os tratamentos a 60 e 100 °C em um Reator Parr, onde as madeiras ficaram submersas em água. Independente do tempo de exposição, os tratamentos realizados a 100 °C mostraram-se mais eficientes, pois desobstruíram os poros, reduziram a higroscopicidade e promoveram maior escurecimento e homogeneização da cor das madeiras, sem alterar a densidade e a resistência mecânica das mesmas.

ABSTRACT Wood, in general, is a material with excellent properties; however, some features may limit its use. In this sense, various thermal treatments are emerging as alternatives to improve the technological properties of wood. In this context, this study aims at analyzing the effects of time and temperature (hydrothermal treatment and freezing) on the physical and mechanical properties of Eucalyptus grandis W. Hill ex Maiden. Three trees were selected, and only the heartwood was used to obtain the test body dimensions of 30 × 8 × 3 cm (length × width × thickness). The treatments were carried out at three temperatures of -20, 60, and 100°C, each at three exposure times (5, 10, and 15 h). Temperature treatment at -20°C was conducted in a domestic freezer, while the treatments at 60 and 100°C were administered in a Parr reactor, where the timber was submerged in water. Regardless of the exposure time, the timbers heat-treated at 100°C showed more efficiency, since this treatment unclogged the pores, reduced hygroscopicity, and promoted further darkening and uniformity of color, without changing the density and mechanical strength of the wood.

RESUMO A fim de melhorar a eficácia global da produção de energia, uma estratégia é o modelo de biorrefinarias, em que todos os componentes de biomassa são totalmente utilizados para produzir uma gama de produtos de maior valor agregado. A lignina kraft é um dos produtos oriundos do processo de produção de celulose e que pode ser utilizado na confecção de materiais densificados. O objetivo deste trabalho foi avaliar o comportamento da adição da lignina extraída do licor negro kraft em briquetes confeccionados com resíduos da indústria moveleira na forma de maravalha e partículas de painéis; em diferentes proporções. Os briquetes foram produzidos em briquetadeira laboratorial, usando as temperaturas de 60, 75 e 90 oC. O tempo de compactação e resfriamento foi de 5 minutos e pressão 68,9 x 105 N.m-2 (1000 PSI). A qualidade dos briquetes foi avaliada em função da determinação da propriedade mecânica. Determinou-se a carga de ruptura dos briquetes. A adição de lignina kraft aos resíduos de madeira nas proporções e temperatura adequadas apresentou vantagens de aumento de resistência mecânica dos briquetes. A lignina kraft apresentou vantagens como aglutinante na produção de briquetes de resíduo de madeira na temperatura de compactação de 90 OC com adição de 20% de lignina kraft e temperaturas de 60 e 75 OC de compactação na proporção de adição de 40 e 60% de lignina kraft, respectivamente.

ABSTRACT In order to improve global effectiveness of energy production, a strategy is the model of bio-refineries in which all the components of biomass are totally used to produce a range of products with aggregated value. The kraft lignin is one of the products originated in the process of cellulose production that can be used in making densified products. The objective of this work was to evaluate the behavior of the addition of extracted kraft lignin of black kraft liquor in briquette manufactures with furniture industry waste, in the form of shavings and panel particles in different proportions. The briquettes were produced in laboratory briquetting, using the temperatures of 60, 75 and 90 oC. The pressing and cooling time was 5 minutes and pressure 68,9 x 105 N.m-2 (1000 PSI). The briquette quality was evaluated through determining the mechanical properties. The kraft lignin in adequate proportions and temperature showed advantages in the increase of resistance and the durability of the briquettes. The kraft lignin presented advantages such as agglutinative in briquette productions from wood waste at a pressing temperature of 90 oC with addition of 20% of kraft lignin, and at pressing temperatures of 60 and 75 oC at a proportion of addition of 40 and 60% of kraft lignin to wood waste, respectively.

RESUMO São muitas as espécies do gênero Eucalyptus que apresentam altos níveis de tensões de crescimento. Essas tensões são esforços mecânicos gerados durante o crescimento da árvore que ajudam a manter o equilíbrio da copa, em resposta a agentes ambientais e silviculturais. As tensões de crescimento são responsáveis pelas rachaduras de topo e pelos empenamentos após o desdobro. O objetivo deste trabalho foi testar cinco técnicas para a redução dos efeitos da tensão de crescimento na produção de toras de Eucalyptus urophylla. Após a obtenção e desdobro das toras foram avaliados as rachaduras, o arqueamento, o encurvamento e o encanoamento. O tratamento com herbicida apresentou os menores índices médios de rachadura (16,63 cm) e de arqueamento (0,23 mm.m-1), enquanto o encurvamento médio foi menor observado em tábuas desdobradas em 72 horas após o abatimento das árvores (0,88 mm.m-1). O desdobro após dez dias ao abate representou a técnica menos eficiente no controle de rachadura, encurvamento e arqueamento. O encanoamento não foi observado durante o processamento das tábuas. A aplicação de herbicida foi a técnica mais eficiente na redução do efeito das tensões de crescimento.

ABSTRACT There are many species of the Eucalyptus genus presents high levels of the growth stress. These stresses are mechanical efforts generated during the tree growth to help maintaining the balance of the cup in response to environmental and silvicultural agents. The stresses are responsible for the cracks of tops and for the warp after unfolding. The objective of this study was to test five different methods to minimize the effects of growth stress on the production of Eucalyptus urophylla sawlogs. The boards produced were then evaluated and measured for cracking, arching, curvature and cupping. The treatment with herbicide presented the smallest medium indexes of cracking (16.63 cm) and of arching (0.23 mm.m-1), while the medium curvature was smaller than observed in boards unfolded in 72 hours after the reduction of the trees (0.88 mm.m-1). Unfolding after ten days of harvesting represented the less efficient technique in the cracking control, curvature and arching. The cupping was not observed during boards processing. The herbicide application was more efficient in the reduction of the effects of the growth tensions.

RESUMO Árvores inclinadas produzem madeira de reação, cujas propriedades são distintas da madeira normal e, podem afetar na produção de carvão vegetal. Este trabalho foi realizado com objetivo de avaliar a qualidade do carvão vegetal procedente da madeira de reação em árvores de plantio comercial inclinadas por ação de ventos. Utilizou-se madeira de um híbrido de Eucalyptus grandis x Eucalyptus urophylla aos seis anos de idade proveniente de plantios localizados em Minas Gerais. Determinaram-se as propriedades físicas e químicas da madeira, e também o rendimento gravimétrico e as propriedades do carvão vegetal. De acordo com os resultados, houve diferenças significativas entre as propriedades da madeira de reação e normal, tendo a madeira de reação menores teores de lignina e extrativos, maior teor de holocelulose e menor densidade básica. No entanto, essas diferenças na madeira de reação não afetaram significativamente as propriedades do carvão vegetal.

ABSTRACT Inclined trees produce reaction wood, whose properties are distinct from normal wood. This situation can affect the production of charcoal. This study was conducted to evaluate the quality of charcoal derived from reaction wood in trees of a commercial plantation inclined due to the action of wind. We used six year old wood from a Eucalyptus grandis xEucalyptus urophylla hybrid from plantations located in Minas Gerais. The physical and chemical properties of the wood were determined as well as the gravimetric yield and charcoal properties. According to the results, there were significant differences between the properties of the reaction and normal wood, with the reaction wood having lower levels of lignin and extractives, greater holocellulose content and low specific gravity. However, these characteristics of reaction wood did not significantly affect the properties of its charcoal.

RESUMO O objetivo da pesquisa foi avaliar a qualidade do tratamento preservativo de moirões de Eucalyptus sp. pelo método de substituição da seiva e comparar a penetração por meio dos métodos tradicionais e de segmentação fotocolorimétrica. Os moirões, com comprimento de 2,0 metros e diâmetro entre 8 e 12 cm, foram expostos às concentrações de 2; 3 e 4% de ingredientes ativos de produto a base de CCB, durante 10 dias. Foram analisadas as penetrações por duas metodologias, sendo uma pelo software Image Pro Plus 4.5, por meio de desempenho de segmentação fotocolorimétrica, e analisadas a retenção do produto em quatro posições nos moirões tratados. As peças submetidas aos tratamentos obtiveram baixa penetração, e por consequência, os valores de retenção foram inferiores do exigido para o contato direto com o solo. Por outro lado, a metodologia proposta por desempenho de segmentação fotocolorimétrica mostrou-se eficiente e, pode ser uma alternativa para determinar a penetração de forma mais precisa e ágil.

ABSTRACT The research object was evaluating the quality of preserving treatment of Eucalyptus sp. fence posts by the sap substitution method and comparing the penetration through the traditional and photocolorimetry segmentation methods. The fence posts, 2,0 meters long and with a diameter between 8 and 12 cm, were exposed to 2, 3 and 4% concentrations of CCB based-product active ingredients for 10 days. The penetrations were analyzed using two methodologies, one by the Image Pro Plus 4.5 software, using photocolorimetry segmentation method performance, and by analyzing the product retention in four positions of the treated fence posts. The treatment submitted pieces attained low penetration and, thus, the retention values were less than the required for direct contact with the ground. On the other hand, the proposed photocolorimetry segmentation methodology was efficient and could be an alternative to determine a more precise and fast penetration.

RESUMO O presente trabalho objetivou avaliar as modificações anatômicas que ocorrem com a carbonização da madeira e determinar as propriedades anatômicas, densidade básica da madeira e densidade aparente do carvão vegetal de clones de Eucalyptus, além de elucidar as possíveis correlações significativas existentes. A microscopia eletrônica de varredura foi efetuada nas seções transversal, longitudinal tangencial e longitudinal radial da madeira e do carvão vegetal. Neste, foi feita a análise morfológica dos poros e densidade aparente. De uma forma geral, as características anatômicas como forma de poros, raios e fibras da madeira apresentaram pouca ou nenhuma modificação devido à carbonização, e a superfície do carvão apresentou estruturas bem definidas. As modificações nos elementos celulares da madeira foram principalmente referentes aos parâmetros quantitativos, como espessura da parede das fibras e diâmetro dos poros. Os clones avaliados apresentaram densidade básica da madeira satisfatória para a produção de carvão vegetal. Os parâmetros anatômicos correlacionaram-se significativamente com a densidade básica da madeira e densidade aparente do carvão vegetal, destacando-se, neste estudo, a fração parede das fibras.

ABSTRACT This study aimed to evaluate the anatomical changes that occur with charred wood and determine the anatomical properties, basic wood density and apparent density of charcoal Eucalyptus clones, besides elucidating the possible existing significant correlations. The scanning electron microscopy was performed in the transverse, longitudinal and tangential longitudinal and radial wood charcoal sections. In the morphological analysis of the pores and the apparent density was made. In general, the anatomical features such as pore radius and the wood fibers showed little or no change due to carbonization of coal surface and showed well defined structures. The changes in cellular elements of wood were mainly related to the quantitative parameters such as wall thickness and pore diameter fibers. The clones showed satisfactory basic density of wood for charcoal production. The anatomical parameters were significantly correlated with basic wood density and apparent density of charcoal, especially, in this study, the fraction of the fiber wall.

RESUMO O Brasil é o maior produtor de carvão vegetal, sendo que Minas Gerais se destaca como o estado com maior produção desse produto. As propriedades da madeira influenciam a qualidade do carvão vegetal, sendo importante conhecê-las, sabendo-se que essas propriedades sofrem variação com a idade da árvore. Sendo assim, este trabalho teve como objetivo determinar as correlações existentes entre idade, as propriedades da madeira e as propriedades do carvão vegetal. Foram avaliados três clones de Eucalyptus sp., em quatro idades, aos 3, 4, 5 e 7 anos, sendo provenientes da Gerdau S/A. De cada árvore foram retirados cinco discos (0%, 25%, 50%, 75%, 100% da altura comercial do tronco), e foram determinadas a relação cerne/alburno, densidade básica, composição química da madeira, poder calorífico superior da madeira e do carvão vegetal, rendimentos gravimétricos, densidade relativa aparente e análise química imediata do carvão vegetal, além dos gases condensáveis e não condensáveis. Foram realizadas correlações entre a idade, propriedades da madeira e do carvão vegetal. Observou-se correlação negativa entre a idade da madeira e o teor de cinzas do carvão vegetal, independentemente do clone avaliados; correlação positiva entre a densidade básica da madeira e a densidade aparente do carvão; correlação positiva entre o teor de lignina da madeira e a densidade aparente do carvão. A relação siringil/guaiacil, que determina a quantidade de cada tipo de lignina presente na madeira, apresentou correlação negativa com o rendimento gravimétrico em carvão vegetal. Dessa forma, pode-se concluir que a idade da árvore influenciou as propriedades da madeira, independente do clone; a idade do material genético não influenciou o rendimento gravimétrico em carvão vegetal; o clone GG 680 apresentou o maior potencial para a produção de carvão, considerando-se somente as propriedades da madeira.

ABSTRACT Brazil is world's greater producer of charcoal, and the Brazilian state Minas Gerais presents the greater production of said product. The wood proprieties influence the charcoal quality, making important to know them, it is known that these proprieties vary according to the age of the tree. With that being said, this research aimed to determine the correlations existing between age, the proprieties of the wood and charcoal proprieties. Three Eucalyptus sp. clones from Gerdau S/A were evaluated, at four ages, 3, 4, 5 and 7. From each tree, five discs were removed (0%, 25%, 50%, 75% and 100% corresponding to the commercial height of the trunk). We determined the core/sapwood relationship, basic density, chemical composition of the wood, the calorific value of the wood and of the charcoal, the gravimetric yields, apparent relative density and charcoal chemical analysis, in addition to the analysis of the condensable and non-condensable gases. Correlations between age, proprieties of the wood and charcoal were performed. It was observed a negative correlation between the age of the wood and charcoal ashes content, regardless the clones evaluated. A positive correlation between the basic density of the wood and the apparent density of the coal and a positive correlation between the lignin of wood content and the coal apparent density were observed, as well. The siringil/guaiacil relation, which determines the quantity of each type of lignin existent on the wood, presented a negative correlation with the gravimetric yields in charcoal. Therefore, it is concluded that the age of the tree influenced the proprieties of the wood, regardless the clone; the age of the genetic material did not influence the gravimetric yield in charcoal; the GG 680 clone presented greater potential to produce charcoal, considering only the proprieties of the wood.

In this study, conventional restorative glass ionomer cement (GIC) was modified by embedding it with mechanically processed cellulose fibers. Two concentrations of fibers were weighed and agglutinated into the GIC during manipulation, yielding Experimental Groups 2 (G2; 3.62 wt% of fibers) and 3 (G3; 7.24 wt% of fibers), which were compared against a control group containing no fibers (G1). The compressive strengths and elastic modulus of the three groups, and their diametral tensile strengths and stiffness, were evaluated on a universal test machine. The compressive and diametral tensile strengths were significantly higher in G3 than in G1. Statistically significant differences in elastic modulus were also found between G2 and G1 and between G2 and G3, whereas the stiffness significantly differed between G1 and G2. The materials were then characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Heterogeneously shaped particles were found on the G2 and G3 surfaces, and the cement matrices were randomly interspersed with long intermingled fibers. The EDS spectra of the composites revealed the elemental compositions of the precursor materials. The physically processed cellulosic fibers (especially at the higher concentration) increased the compressive and diametral tensile strengths of the GIC, and demonstrated acceptable elastic modulus and stiffness.