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Papers by Douglas Carvalho

Tecno-Lógica

O presente estudo teve como objetivo avaliar a eficiência operacional da máquina principal (serra... more O presente estudo teve como objetivo avaliar a eficiência operacional da máquina principal (serra de fita) no desdobro de toras de Eucalyptus spp.. As toras foram divididas em quatro classes diamétricas (classe 1: 21,0 a 30,9 cm; classe 2: 31,0 a 40,9 cm; classe 3: 41,0 a 50,9 cm; classe 4: > 51,0 cm) cada classe com três comprimentos de tora (3,60 m; 4,10 m; 5,20 m). As duas classes diamétricas inferiores (1 e 2) foram submetidas ao modelo de desdobro tangencial alternado e as toras das duas classes diamétricas superiores (3 e 4) foram submetidas ao modelo de desdobro radial. Em cada classe diamétrica as toras foram avaliadas quanto à conicidade, à influência do comprimento e ao diâmetro da tora na eficiência operacional. Para cada modelo de desdobro foram geradas equações para estimar a eficiência operacional. O acréscimo em comprimento e diâmetro das toras para cada modelo de desdobro proporcionou aumento da eficiência operacional média. As estratificações dimensionais e as ba...

Field trial of rotting for certain periods is the most relevant method to evaluate mechanical pro... more Field trial of rotting for certain periods is the most relevant method to evaluate mechanical properties of wood. With this, the objective of this research was to evaluate the strength and stiffness of the wood of Eucalyptus dunnii, Eucalyptus robusta, Eucalyptus tereticornis and Hovenia dulcis woods, exposed to biotic and abiotic agents attack, in
open-field and inside forest. Two-hundred forty samples with dimensions of 20 x 20 x 300 mm (thickness x width x length) were prepared. The wood were exposed for 405 days, being collected every 45 days for bending strength tests to determine the modulus of elasticity (MOE) and modulus of rupture (MOR). Eucalyptus tereticornis wood
presented the average values superior to the other species, being 16469.2; 14700.8 and 11025.2 MPa for MOE and 132.71; 81.57 and 69.93 MPa for MOR, corresponding to the control, field environment and forest environment respectively. The wood of Eucalyptus dunnii shows a
greater decrease in the resistance to static bending of the natural material in relation to the material exposed in the environments. Eucalyptus robust didn’t present significant alteration of resistance and stiffness between the test specimens and those exposed to the environments. Eucalyptus tereticornis presents MOE and MOR after
superior exposure to the other species. The wood exposed in the open-field resulted in reduction of MOE and MOR compared to the woods exposed inside the forest for all species

The present study aimed to assess the yield in eucalyptus slabs for the obtainment of battens to ... more The present study aimed to assess the yield in eucalyptus slabs for the obtainment of battens to be used in the production of higher value-added products. For this purpose, 15 logs of E. grandis and 15 logs of E. saligna, which were separated into three diametric classes of five logs for each species, were used: diameter class 1 (25-32 cm); diametric class 2 (33-39 cm); and diametric class 3 (> 40 cm). Then, they were cubed and assessed regarding the taper and breakdowns in the band saw. The slabs were removed for assessment of quality, yield and yield in battens obtained for each studied species. The results indicated average classification for basic density, and good dimensional stability for E. grandis and E. saligna wood. The logs taper and the yields observed were not significant for either species. However, the yields in slabs and yields in battens slightly decreased as the diameter of the logs increased. Thus, logs with greater yields in slabs had lower yields in battens. Therefore, it is possible to use slabs for the production of battens, mainly in industries that process high amounts of logs. Resumo Rendimento em costaneira de eucalipto para aproveitamento na obtenção de sarrafos. O presente trabalho teve o objetivo de avaliar o rendimento em costaneira de eucalipto para aproveitamento na obtenção de sarrafos a serem utilizados na produção de produtos de maior valor agregado. Para isso, foram utilizadas 15 toras de E. grandis e 15 toras de E. saligna, as quais foram separadas em três classes diamétricas de cinco toras para cada espécie: classe diamétrica um (25-32 cm); classe diamétrica dois (33-39 cm); e classe diamétrica três (> 40 cm). Em seguida, as mesmas foram cubadas e avaliadas com relação à conicidade e desdobras em serra fita. As costaneiras foram retiradas para avaliação de qualidade, rendimento e rendimento em sarrafos obtidos para cada espécie estudada. Os resultados obtidos indicaram classificação média da massa especifica obtida, com boa estabilidade dimensional da madeira de E. grandis e E. saligna. A conicidade das toras e os rendimentos observados não foram significativos nas duas espécies, porém os rendimentos em costaneiras e os rendimentos em sarrafos tiveram um ligeiro decréscimo com o aumento do diâmetro das toras. Toras com maior rendimento em costaneiras tiveram menor rendimento em sarrafos. Assim sendo, o aproveitamento de costaneiras para produção de sarrafos pode ser feito principalmente nas indústrias que processam elevadas quantidades de toras. Palavras-chaves: Conicidade, desdobro, qualidade da madeira, madeira sem refilo, serragem.

This study aimed to evaluate the natural durability of Eucalyptus dunnii, Eucalyptus robusta, Euc... more This study aimed to evaluate the natural durability of Eucalyptus dunnii, Eucalyptus robusta,
Eucalyptus tereticornis and Hovenia dulcis woods subjected to accelerated testing in laboratory
with rotting fungi Gloeophyllum trabeum, causer of brown rot; and Trametes versicolor, causer
of white rot. The samples remained 12 weeks in contact with the fungi, after that, we calculated
the percentages of mass loss, classified according to the degree of natural resistance and assessed
according to the rate of susceptibility to attack. The averages of the results were compared by
the Tukey test at 5% significance level. Eucalyptus robusta wood was classified as resistant and
Hovenia dulcis wood was classified as non-resistant to both fungi. The index of susceptibility to
attack indicated that the species studied present acceptable values and that they are more resistant
to the attack of fungi compared with reference species (Pinus sp.; Cecropia sp.)

Tecno-Lógica

O presente estudo teve como objetivo avaliar a eficiência operacional da máquina principal (serra... more O presente estudo teve como objetivo avaliar a eficiência operacional da máquina principal (serra de fita) no desdobro de toras de Eucalyptus spp.. As toras foram divididas em quatro classes diamétricas (classe 1: 21,0 a 30,9 cm; classe 2: 31,0 a 40,9 cm; classe 3: 41,0 a 50,9 cm; classe 4: > 51,0 cm) cada classe com três comprimentos de tora (3,60 m; 4,10 m; 5,20 m). As duas classes diamétricas inferiores (1 e 2) foram submetidas ao modelo de desdobro tangencial alternado e as toras das duas classes diamétricas superiores (3 e 4) foram submetidas ao modelo de desdobro radial. Em cada classe diamétrica as toras foram avaliadas quanto à conicidade, à influência do comprimento e ao diâmetro da tora na eficiência operacional. Para cada modelo de desdobro foram geradas equações para estimar a eficiência operacional. O acréscimo em comprimento e diâmetro das toras para cada modelo de desdobro proporcionou aumento da eficiência operacional média. As estratificações dimensionais e as ba...

Field trial of rotting for certain periods is the most relevant method to evaluate mechanical pro... more Field trial of rotting for certain periods is the most relevant method to evaluate mechanical properties of wood. With this, the objective of this research was to evaluate the strength and stiffness of the wood of Eucalyptus dunnii, Eucalyptus robusta, Eucalyptus tereticornis and Hovenia dulcis woods, exposed to biotic and abiotic agents attack, in
open-field and inside forest. Two-hundred forty samples with dimensions of 20 x 20 x 300 mm (thickness x width x length) were prepared. The wood were exposed for 405 days, being collected every 45 days for bending strength tests to determine the modulus of elasticity (MOE) and modulus of rupture (MOR). Eucalyptus tereticornis wood
presented the average values superior to the other species, being 16469.2; 14700.8 and 11025.2 MPa for MOE and 132.71; 81.57 and 69.93 MPa for MOR, corresponding to the control, field environment and forest environment respectively. The wood of Eucalyptus dunnii shows a
greater decrease in the resistance to static bending of the natural material in relation to the material exposed in the environments. Eucalyptus robust didn’t present significant alteration of resistance and stiffness between the test specimens and those exposed to the environments. Eucalyptus tereticornis presents MOE and MOR after
superior exposure to the other species. The wood exposed in the open-field resulted in reduction of MOE and MOR compared to the woods exposed inside the forest for all species

The present study aimed to assess the yield in eucalyptus slabs for the obtainment of battens to ... more The present study aimed to assess the yield in eucalyptus slabs for the obtainment of battens to be used in the production of higher value-added products. For this purpose, 15 logs of E. grandis and 15 logs of E. saligna, which were separated into three diametric classes of five logs for each species, were used: diameter class 1 (25-32 cm); diametric class 2 (33-39 cm); and diametric class 3 (> 40 cm). Then, they were cubed and assessed regarding the taper and breakdowns in the band saw. The slabs were removed for assessment of quality, yield and yield in battens obtained for each studied species. The results indicated average classification for basic density, and good dimensional stability for E. grandis and E. saligna wood. The logs taper and the yields observed were not significant for either species. However, the yields in slabs and yields in battens slightly decreased as the diameter of the logs increased. Thus, logs with greater yields in slabs had lower yields in battens. Therefore, it is possible to use slabs for the production of battens, mainly in industries that process high amounts of logs. Resumo Rendimento em costaneira de eucalipto para aproveitamento na obtenção de sarrafos. O presente trabalho teve o objetivo de avaliar o rendimento em costaneira de eucalipto para aproveitamento na obtenção de sarrafos a serem utilizados na produção de produtos de maior valor agregado. Para isso, foram utilizadas 15 toras de E. grandis e 15 toras de E. saligna, as quais foram separadas em três classes diamétricas de cinco toras para cada espécie: classe diamétrica um (25-32 cm); classe diamétrica dois (33-39 cm); e classe diamétrica três (> 40 cm). Em seguida, as mesmas foram cubadas e avaliadas com relação à conicidade e desdobras em serra fita. As costaneiras foram retiradas para avaliação de qualidade, rendimento e rendimento em sarrafos obtidos para cada espécie estudada. Os resultados obtidos indicaram classificação média da massa especifica obtida, com boa estabilidade dimensional da madeira de E. grandis e E. saligna. A conicidade das toras e os rendimentos observados não foram significativos nas duas espécies, porém os rendimentos em costaneiras e os rendimentos em sarrafos tiveram um ligeiro decréscimo com o aumento do diâmetro das toras. Toras com maior rendimento em costaneiras tiveram menor rendimento em sarrafos. Assim sendo, o aproveitamento de costaneiras para produção de sarrafos pode ser feito principalmente nas indústrias que processam elevadas quantidades de toras. Palavras-chaves: Conicidade, desdobro, qualidade da madeira, madeira sem refilo, serragem.

This study aimed to evaluate the natural durability of Eucalyptus dunnii, Eucalyptus robusta, Euc... more This study aimed to evaluate the natural durability of Eucalyptus dunnii, Eucalyptus robusta,
Eucalyptus tereticornis and Hovenia dulcis woods subjected to accelerated testing in laboratory
with rotting fungi Gloeophyllum trabeum, causer of brown rot; and Trametes versicolor, causer
of white rot. The samples remained 12 weeks in contact with the fungi, after that, we calculated
the percentages of mass loss, classified according to the degree of natural resistance and assessed
according to the rate of susceptibility to attack. The averages of the results were compared by
the Tukey test at 5% significance level. Eucalyptus robusta wood was classified as resistant and
Hovenia dulcis wood was classified as non-resistant to both fungi. The index of susceptibility to
attack indicated that the species studied present acceptable values and that they are more resistant
to the attack of fungi compared with reference species (Pinus sp.; Cecropia sp.)