Abstract: The differentiation between the charcoal produced from (Eucalyptus) plantations and native forests is essential to control, commercialization, and supervision of its production in Brazil. The main contribution of this study is to identify the charcoal origin using macroscopic images and Deep Learning Algorithm. We applied a Convolutional Neural Network (CNN) using VGG-16 architecture, with preprocessing based on contrast enhancement and data augmentation with rotation over the training set images. on the performance of the CNN with fine-tuning using 360 macroscopic charcoal images from the plantation and native forests. The results pointed out that our method provides new perspectives to identify the charcoal origin, achieving results upper 95 % of mean accuracy to classify charcoal from native forests for all compared preprocessing strategies.

Abstract: Thermal treatments have the effect of reducing the hygroscopicity and improving the resistance to microbiological attack of wood by the degradation of its chemical constituents. During the treatments, the mass of the wood is reduced, a factor that can affect the quality of the materials according to their use. The objective was to verify the effect of the thermal treatment variables on the thermogravimetric properties and the chemical composition of Eucalyptus grandis. The treatments were carried out in a vacuum oven with three atmosphere conditions - vacuum; N2; vacuum+N2 at temperatures of 140, 180 and 220 °C for 6 hours. It was observed that the mass loss during treatments differed only according to the temperatures used. The extractive content, total lignin and holocellulose presented significant changes only at 220°C in all three atmospheres. In the thermogravimetric analysis, the greatest value of residual mass was found in the treatment that used nitrogen and 220 °C, thus demonstrating that this treatment was more invasive, leading to the conclusion that the vacuum application can help to reduce the degradation of the constituents of the eucalypt wood. Wood, which can lead to the production of thermally treated wood without great losses in the mechanical properties.

Abstract: Brazilian productivity of eucalyptus trees is one of the highest in the world, and it has sustainable and viable conditions to supply the demand for woody biomass in a large quantity and diversity. This favorable situation makes Brazil one of the countries with the greatest potential for the production development of torrefied woody biomass on a commercial scale. Torrefaction is a mild pyrolysis applied to increase the energy quality of the feedstock. The aim of this study was to evaluate the Brazilian potential of woody biomass torrefaction for energy purposes. An experimental study was performed evaluating this thermal treatment of eucalyptus wood chips on a semi-continuous screw reactor developed by a Brazilian university. The results showed the increases in the energy quality of eucalyptus wood chips as a function of torrefaction temperature and time. This thermal treatment was technically feasible for the hygroscopicity reduction and the increases of fixed carbon and calorific values of the woody biomass.

RESUMO O objetivo deste trabalho foi determinar as propriedades de painéis aglomerados confeccionados com partículas de bagaço de cana-de-açúcar in natura e aquecidas a 250 °C durante 5 minutos. Foram empregadas várias proporções de partículas na confecção dos painéis e as suas propriedades foram comparadas com as propriedades de um painel fabricado com partículas de Pinus sp. Os painéis foram produzidos com 8% de adesivo à base de tanino formaldeído, 0,5% de emulsão parafínica e prensados a 32 kgf.cm-2, por 10 minutos, à temperatura de 180 °C. Determinou-se a densidade básica das partículas in natura e termotratadas, sua composição química bem como a taxa de compressão necessária para obter painéis com densidade igual a 0,75 g.cm-3. Determinou-se a densidade básica dos painéis, umidade de equilíbrio higroscópico, inchamento em espessura, expansão linear, adsorção de vapor de água, módulo de elasticidade e de ruptura, tração perpendicular, arrancamento de parafuso e dureza Janka. As densidades básicas das partículas de Pinus e do bagaço de cana sem e com tratamento térmico foram de 0,46, 0,27 e 0,30 g.cm-3, respectivamente. A massa específica média dos painéis foi igual a 0,74 g.cm-3 sem diferença significativa entre eles. Geralmente, os painéis fabricados com partículas de cana-de-açúcar foram menos higroscópicos e dimensionalmente mais estáveis do que os painéis fabricados com partículas de Pinus. Contudo, a resistência à tração perpendicular, o arrancamento de parafuso e a dureza de Janka destes painéis foram maiores. O tratamento térmico das partículas de bagaço de cana resultou em melhores propriedades mecânicas de tração perpendicular e dureza de Janka. De modo geral, os painéis estão dentro dos limites estabelecidos pela norma ANSI A208.1. Portanto, é possível substituir painéis confeccionados com partículas de Pinus por bagaço de cana de açúcar, desde de que, pelo menos 25% das partículas sejam tratadas termicamente durante 5 minutos à temperatura de 250ºC.

ABSTRACT The objective of this work was to determine the properties of particleboard panels made of “in natura” sugarcane bagasse particles, heated at 250 °C for 5 minutes. Various particle proportions were utilized to produce the panels and their properties were compared with that of a panel made of Pinus sp. The panels were produced with 8% tannin formaldehyde adhesive, and 0.5% paraffin emulsion, being pressed at 32 kgf.cm-2 for 10 minutes at 180 ° C. It was determined the basic density of the “in natura” and heat-treated particles, their chemical composition, as well as the compression ratio necessary to obtain panels with density equal to 0.75 g.cm-3. The basic density of the panels, hygroscopic equilibrium humidity, thickness swelling, linear expansion, water vapor adsorption, modulus of elasticity and rupture, perpendicular traction, screw pullout, and Janka hardness were determined. The basic densities of Pinus particles and sugarcane bagasse without and with heat treatment were 0.46, 0.27 and 0.30 g.cm-3, respectively. The average specific mass of the panels was 0.74 g.cm-3 with no significant difference between them. Generally, panels made of sugarcane particles were less hygroscopic and dimensionally more stable than panels made of Pinus particles. However, the perpendicular tensile strength, screw pullout and Janka hardness of these panels were higher than for the Pinus panels. The heat treatment of sugarcane bagasse particles resulted in better mechanical properties of perpendicular traction and Janka hardness. In general, the panels are within the limits set by ANSI A208.1. It is therefore possible to replace panels made of Pinus particles for the ones made of sugarcane bagasse, provided that at least 25% of the particles are heat treated for 5 minutes at 250 ° C.

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 Charcoal produced from reforested wood can be distinguished from the charcoal derived from the wood of native species. This identification is very important for the trade, control and monitoring of charcoal production in Brazil. This study investigated the potential of texture analysis for classifying the charcoal based on origin (eucalyptus or native) and species. A total of 17 wood species were studied, five of which belonged to genus Eucalyptus and 12 were native to the Zona da Mata Mineira. Texture features based on the gray level co-occurrence matrix were extracted from digital images. The linear discriminant analysis was used to classify the images with these features. Employing 10 features, 96.2% accuracy was achieved for the classification by origin and 90.4% for the categorization by species. Texture analysis was shown to be a favorable and effective method that could facilitate the establishment of semiautomated techniques to classify the charcoal based on origin or species.

RESUMO O crescimento da demanda mundial por madeira implica na busca de novas espécies de rápido crescimento com potencial silvicultural e, nesse cenário, as espécies nativas como o paricá. Assim, o objetivo deste trabalho foi determinar as propriedades físicas e mecânicas da madeira da espécie Schizolobium amazonicum (paricá). As árvores foram coletadas em plantios comerciais localizados no norte do Brasil, com idades de 5, 7, 9 e 11 anos. Das árvores de cada idade foram obtidas quatro toras no sentido longitudinal das árvores e, posteriormente, um pranchão diametral de cada tora para fabricação dos corpos de prova, os quais foram utilizados para avaliar algumas propriedades físicas e mecânicas da madeira. A densidade básica do paricá reduziu no sentido base-topo e não houve diferença entre as posições radiais, em média, a densidade básica dessa madeira caracterizou-se como baixa. A região próxima da casca apresentou menor contração longitudinal, e também, maior homogeneidade dessa propriedade ao longo do tronco, enquanto para a contração tangencial a menor variação foi encontrada na região próxima à medula. A contração da madeira de paricá foi caracterizada como baixa. A idade influenciou a maioria das propriedades mecânicas, tendo a tora da base os maiores valores de resistência mecânica.

ABSTRACT Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil). Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

RESUMO O objetivo deste trabalho foi determinar os efeitos da idade das árvores e das posições medula-casca e base-topo nas características anatômicas e o efeito da idade nos componentes químicos da madeira de Schizolobium amazonicum (paricá). O material foi obtido de plantios comerciais nos estados do Maranhão e Pará, com idades de 5, 7, 9 e 11 anos. Das árvores de cada idade foram obtidas as três primeiras toras (de 2,7 m de comprimento cada). Para a caracterização química da madeira analisou-se apenas o efeito da idade. As dimensões das fibras aumentaram no sentido medula-casca, enquanto a espessura da parede reduziu e o comprimento das fibras aumentou juntamente com a idade. A largura das fibras e o diâmetro do lume aumentaram no sentido base-topo. A madeira de paricá apresentou baixo teor de extrativos e de hemiceluloses, e alto teor de celulose. As características anatômicas foram mais afetadas pelos fatores em estudo do que a composição química, evidenciando que os elementos químicos da madeira são mais estáveis com a idade em relação aos caracteres anatômicos.

ABSTRACT The objective of this study was to determine the effects of tree age and of pith-bark and base-top positions on anatomical characteristics, and the effect of age on the chemical components of Schizolobium amazonicum (Paricá wood). The material was obtained from commercial plantations in the states of Maranhão and Pará with ages of 5, 7, 9 and 11 years. The first three logs (2.7 m length each) were obtained from the trees of each age. Only the effect of age was analyzed for the chemical characterization of the wood. The dimensions of the fibers increased along the pith-bark direction, while wall thickness decreased and the length of the fibers increased with aging. The width of the fibers and the lume diameter increased in the base-top direction. Paricá wood presented low extractive and hemicellulose content, and high cellulose content. The anatomical characteristics were more affected by the factors under study than the chemical composition, evidencing that the chemical elements of the wood are more stable with aging in relation to the anatomical characteristics.

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 O uso da biomassa florestal como lenha ou seu derivado carvão vegetal, pode gerar vantagens ambientais e econômicas para a matriz energética brasileira. Nesse contexto, o objetivo principal foi avaliar o potencial energético de alguns materiais genéticos de eucalipto, que são utilizados no setor de produção de carvão vegetal. Foram analisados seis materiais de Eucalyptus ssp. na idade de sete anos provenientes de plantios comerciais, com espaçamento 3 x 3 m, cultivados no Alto Vale do Jequitinhonha, em Minas Gerais. Baseando-se nos dados de produção, no incremento médio anual e nas análises físicas e químicas da madeira e do carvão com ela produzidos, foram estimados parâmetros para se comparar o potencial de cada material genético, como a massa e a energia da madeira e do carvão por hectare, além da densidade energética. Os resultados demonstram que um material de Eucalyptus urophylla possui maior potencial energético em relação aos demais, por apresentar maior energia/hectare estimada para sua madeira e consequentemente para seu carvão produzido. Mas um material de Eucalyptus cloeziana apresentou maior densidade energética da madeira e de seu carvão, mostrando vantagens principalmente no transporte.

ABSTRACT The use of forest biomass or its derived charcoal as firewood can generate environmental and economic advantages for the Brazilian energy matrix. In this context, the main objective was to evaluate the energy potential of certain eucalyptus genetic materials, which are used by the charcoal production sector. We have evaluated six materials of Eucalyptus ssp. at the age of seven years from commercial plantations, spaced 3 x 3m, grown in the Alto Vale do Jequitinhonha, in Minas Gerais. Based on the production data, the average annual increment and the physical and chemical analyzes of the wood and the charcoal produced with it, we have estimated parameters to compare the potential of each genetic material, such as mass and energy of wood and charcoal per hectare, as well as the energy density. The results show that a material of Eucalyptus urophylla has greater energetic potential in relation to the others because it presents higher energy/ hectare estimated for its wood and consequently for charcoal produced with it. However, a material of Eucalyptus cloeziana presented a higher energetic density of the wood and its charcoal, showing advantages mainly in the transport.

RESUMO Objetivou-se neste estudo avaliar o efeito da temperatura final da torrefação nas propriedades energéticas da madeira. Foram aplicados quatro tratamentos com três repetições constituídos por partículas de madeira não torrificadas e partículas torrificadas nas temperaturas de 170, 220 e 260 ºC. Observaram-se melhores propriedades físicas, químicas e térmicas das partículas em função da temperatura de torrefação. Comparando com a testemunha, as partículas torrificadas na temperatura final mais elevada (260 ºC) apresentaram diferenças significativas na densidade a granel - de 239 para 396 kg/m3; umidade de equilíbrio higroscópico - de 12,3 para 5,7%; teor de carbono fixo - de 13,0 para 24,8%; poder calorifico - de 4465 para 4945 kcal/kg; e densidade energética - de 882 para 1727 Mcal/m3. Concluiu-se que a torrefação apresentou um efeito positivo nas propriedades energéticas da madeira.

ABSTRACT The objective of this study was to evaluate the effect of the final torrefaction temperature on the energy properties of wood. It was applied four treatments with three replicates, consisting of untreated wood particles and particles torrefied at temperatures of 170, 220 and 260ºC. Better physical, chemical and thermal properties of the particles were observed as a function of the torrefaction temperature. Comparing with the control group, the particles torrefied at the highest final temperature (260ºC) showed significant differences in bulk density - from 239 to 396kg/m3; the equilibrium moisture content changed from 12.3 to 5.7%; fixed carbon content - from 13.0 to 24.8%; heating value - from 4,465 to 4,945kcal/kg; and energy density - from 882 to 1,727Mcal/m3. It was concluded that torrefaction had a positive effect on the energy properties of the wood.

RESUMO O objetivo deste trabalho foi avaliar a velocidade de secagem de toras de Eucalyptus urophylla a altas temperaturas e a influência da presença ou ausência de casca e do diâmetro da madeira na taxa de secagem. Utilizaram-se toretes de Eucalyptus urophylla com 60 cm de comprimento, em três classes diamétricas: 8-12 cm; 12,1-16cm e 16,1-20 cm. Os toretes foram submetidos à secagem em estufa com circulação forçada de ar, na presença ou ausência de casca em cinco temperaturas: 50, 75, 100, 125 e 150ºC. Determinou-se a massa e a umidade inicial de cada torete e com pesagens periódicas acompanhou-se a perda de água, encerrando o processo de secagem quando os toretes de madeira atingiam a umidade de 20%. A taxa de secagem foi calculada por meio da relação entre a perda total de umidade e o tempo total em horas para que as toras atingissem a umidade estabelecida. Conclui-se que o aumento da temperatura promove o aumento da taxa de secagem, sendo maior para as toras de menor diâmetro em relação às toras de maior diâmetro e na secagem das toras de eucalipto em temperaturas superiores a 100ºC, o efeito da casca não foi significativo. Conclui-se, também, que a melhor condição de operação de secadores artificiais para a madeira de eucalipto em tora seria em temperatura de 125ºC, com presença de casca e separadas em classes diamétricas.

ABSTRACT The objective of this work was to evaluate the drying speed of Eucalyptus urophylla logs in high temperatures and the influence of the presence or absence of bark and also the diameter of the log in the drying rate. Eucalyptus logs 60 cm long were divided into three diameter classes: 8-12 cm; 12,1-16 cm and 16,1-20 cm. The logs were dried in a heater with forced air circulation, in the presence or absence of bark in five temperatures: 50, 75, 100, 125 and 150ºC. The mass and the initial moisture were determined from each log and the water loss was kept up with periodic weightings, closing the drying process when the logs reached 20% moisture. The drying rate of the logs was calculated using the ratio between the total loss of moisture and the time in hours in order to reach the established moisture. It was concluded that the increase in temperature promotes the raise of the drying ratio, as being higher for smaller logs in relation to bigger ones and in addition to this, the bark effect was not significant in the drying of eucalyptus logs above 100ºC. It was also concluded that the best conditions for the operation of artificial dryers for Eucalyptus logs containing bark and separated in diameter classes would be at 125ºC.

RESUMO O trabalho teve como objetivo determinar a influência das propriedades químicas (composição elementar, teores de extrativos totais, lignina total e holocelulose) e relação siringil/guaiacil, da madeira de diferentes materiais genéticos de eucalipto na produção de carvão vegetal. Utilizaram-se na pesquisa quatro clones híbridos de Eucalyptus, aos 7 anos de idade, sendo 6 árvores por clone, totalizando 24 unidades amostrais. Houve diferença significativa, a 5% de significância, entre os tratamentos para a composição elementar, teores de extrativos totais, lignina total e holocelulose e relação siringil/guaiacil da madeira, como também, para os rendimentos gravimétricos em carvão vegetal, em gases condensáveis e em gases não condensáveis, teores de carbono fixo e de materiais voláteis e para o poder calorífico superior do carvão vegetal. Para o teor de cinzas e densidade relativa aparente do carvão não foram observadas diferenças significativas ao mesmo nível de significância. Concluiu-se que existe variabilidade na qualidade da madeira dos quatro materiais genéticos avaliados, tendo, os mesmos, correlações distintas, tanto no rendimento quanto na qualidade do carvão vegetal. Todos os materiais genéticos apresentaram, de modo satisfatório, rendimento gravimétrico em carvão vegetal e qualidade. As madeiras dos clones com baixa relação siringil/guaiacil apresentaram aumento no rendimento em carvão vegetal. A composição química das madeiras dos quatro clones, de modo geral, não apresentou correlações significativas, a 5% de significância, no rendimento e qualidade do carvão.

ABSTRACT The objective of this study was to determine the influence of the chemical properties (elemental composition, levels of extractives, lignin total and holocellulose) and the syringyl/guaiacyl, wood of different Eucalyptus genetic materials in the production of charcoal. It was used in the study four hybrid clones, at age of 7 years, 6 trees per clone, totaling 24 sampling units. There was significant difference, at 5% significance, between treatments for elemental composition, levels of extractives, lignin total and holocellulose and the wood syringyl/guaiacyl, as well as for gravimetric yields in charcoal, condensable gases and non-condensable gases, levels of fixed carbon and volatiles, and for the higher calorific value of charcoal. For the ash content and relative apparent density of charcoal were not observed significant differences at the same level of significance. Concluded that there is variability in the wood quality of four evaluated genetic materials, having the same, distinct correlations, thus the yield and the quality of charcoal. All genetic material presented satisfactorily gravimetric yield in charcoal and quality. The woods of clones with low syringyl/guaiacyl ratio showed an increase in yield in charcoal. The chemical composition of woods from the four clones, in general, showed no significant correlations, the 5% significance level, at the yield and quality of charcoal.

RESUMO Este trabalho teve como objetivo avaliar chapas de partículas do tipo aglomerado convencional, chapas tipo Medium Density Particleboard (MDP) e as do tipo aglomerado com inclusão laminar. As chapas avaliadas foram fabricadas com partículas de Acacia mangium e no aglomerado com inclusão laminar utilizaram-se lâminas de Schizolobium amazonicum. O aglomerado convencional e o aglomerado com inclusão laminar apresentaram umidade de equilíbrio higroscópico estatisticamente superior ao MDP. O aglomerado com inclusão laminar apresentou maior índice de inchamento em espessura após duas horas de imersão em água, valores de módulo de ruptura em flexão estática maiores e maior resistência ao arrancamento de parafuso. As chapas do tipo MDP apresentaram maior resistência à tração perpendicular. Não foram observadas diferenças significativas nas demais propriedades. Conclui-se que a inclusão laminar melhorou o módulo de ruptura e o arrancamento de parafuso, enquanto a utilização de partículas finas nas faces melhorou as propriedades físicas das chapas.

ABSTRACT This study aimed to evaluate physical and mechanical properties of conventional agglomerate, medium density particleboard and agglomerate with laminate inclusion. Particleboards were made of Acacia mangium particles and laminas of Schizolobium amazonicum were used to produce agglomerate with laminate inclusion. Conventional agglomerate and agglomerate with laminate inclusion showed hygroscopic equilibrium moisture statistically superior to MDP. Agglomerate with laminate inclusion showed the highest rate of thickness swelling after 2 hours of immersion in water, the highest modulus of rupture in bending strength and the best screw withdraw resistance. MDP presented the highest mean value of board internal bond strength. There were no significant differences in other evaluated properties. It was concluded that laminate inclusion improved modulus of rupture and screw withdraw resistance while the use of fine particles on the faces improved physical properties of the particleboards.

Heat treatment improves some wood properties namely: equilibrium moisture, dimensional stability and durability and mechanical properties. In this study, the heat treatment was applied to woods of three natural species from Brazil: Aspidosperma populifolium (peroba mica), Dipteryx odorata (cumaru) and Mimosa scabrella (bracatinga). The woods were heated in an oven under vacuum and under nitrogen, at 180, 200, and 220°C for one hour. The untreated and heat-treated woods were characterized in relation to equilibrium moisture content, basic density, shrinkage, Janka hardness, and bending MOR and MOE according to NBR 7190 standards. All the thermal rectified woods showed a reduction in the hygroscopic equilibrium content, especially when the heating was under vacuum from 13-15% in the untreated woods to 1-3% for vacuum treatment at 220°C. The dimensional stability was improved to only a small extent e.g. volumetric shrinkage tended to decrease with increasing temperature. The mechanical properties were affected differently for the three wood species. Heat- treated cumaru showed increased Janka hardness, MOR and MOE; and peroba mica increased MOR and MOE but not Janka hardness; while bracatinga was less influenced by the heat treatment.