Joaquim Carlos Gonçalez

Study of industrial boiling process on walnut colour: Experimental study under industrial conditions

Juglans regia) logs, measured during boiling water process under industrial conditions. The colour changes in sapwood and heartwood evolution were analysed according to the previous results obtained in laboratory. As it was expected, the sapwood color changes quickly during the first 10 hours and definitely after 30 hours of industrial treatment. Its colour is darker and redder. Heartwood behavior is quite different because its colour is changing slowly during the first 10 hours and important changes are occuring after the 39 first hours. These mean results were obtained on the four logs studied. This work precise the particular behavior of the color of wood during boiling and the efficient method used. This study may be used by industries, which are concerned by heating treatment before slicing, and applied to other species.Juglans regia), die während der Behandlung in kochendem Wasser bei Industriebedingungen entstehen. Die Verfärbungen im Splint- und Kernholz wurden analysiert unter Verwendung früherer Ergebnisse aus Laboruntersuchungen. Wie erwartet erfolgt die Verfärbung im Splintholz rasch während der ersten 10 Stunden. Nach 30 Stunden wird ein Endwert erreicht. Die farbe wird dunkler und rötlicher. Die Farbänderungen im Kernholz verlaufen ander; sie beginnen sehr langsam während der ersten 10 Stunden und deutliche Farbänderungen finden erst nach 39stündigem Kochen statt Die Ergebnisse werden als Mittel aus vier Rundhölzern genommen. Sie präzisieren die spezielle Verfärbungwährend des Kochens. Die verwendete Methode erwies sich als effektiv. Die Untersuchung könnte verwendet werden in Industrieprozessen, in welchen Erhitzen oder Dämpfen vor der Auftrennung des Holzes eingesetzt wird. Die Ergebnisse können auch auf andere Holzartn übertragen werden.

AESTHETICS APPRECIATION OF WOOD COLOUR AND PATTERNS BY COLORIMETRY: PART 1. COLORIMETRY THEORY FOR THE CIELAB SYSTEM

The colorimetry theory for the CIELab system today allows us to compute the chromatic coordinates of the raw timber colour along the wood - chain industry. The wood industry is nd strongly behind in such areas. Progress in the wood appearance description by means of colour and pattern characteristics would be suitable to classify the wood. It would also help to match pieces of wood in furniture and inside the houses, to study the wood colour change in wood ageing by photodecoloration or by drying operations, and to improve wood colour variability. Key Words: wood colour; colorimetry theory.

Fotodegradação de duas espécies de madeiras tropicais: jatobá (Hymenaea courbaril) e tauari (Couratari oblongifolia) Submetidas à radiação ultravioleta

Objetivou-se, com este trabalho, acompanhar o processo de fotodegradacao da cor natural superficial de madeiras de duas especies tropicais quando submetidas a radiacao artificial ultravioleta. As duas especies de madeiras pesquisadas foram o jatoba (Hymenaea courbaril) de coloracao marrom avermelhada, e tauari (Couratari oblongifolia) de coloracao oliva amarelado. As amostras destas madeiras foram submetidas a quatro ciclos de radiacao ultravioleta (UV), no comprimento de onda de 350 nm, perfazendo-se um total de 168 horas de irradiacao. A mudanca da cor natural das madeiras, indicativo do processo de fotodegradacao, foi monitorada por espectrocolorimetria. As madeiras das duas especies sofreram alteracao de cor causada pela fotodegradacao, havendo um escurecimento dessas, que foi quantificado pela intensidade da luz refletida. O tauari apresentou-se como a especie mais resistente a radiacao UV e o jatoba apresentou maior tendencia para avermelhar-se. Ambas as especies foram classificadas como madeiras com variacao de cor muito apreciavel.

Comportamento da cor de lâminas de madeira de Pau-marfim (Balfourodendron riedelianum) tratada com produtos de acabamento

This study tested products to combat aging of wood. Through an aging chamber and a spectrocolorimetry device, the influence of chemical finishing products applied to wood were characterized during artificial photodegradation process. The aging of Balfourodendron riedelianum was monitored through 8.807 colorimetry measurements, with the samples undergoing cycles of ultraviolet radiation for periods of: 20, 40, 60, 80, 120, 180, 250, 310, 410 and 500 hours. The data was loaded to Excel and processed. The CIE La*b* system of 1976 showed the color changes. The use of a sealant caused a greater variation in the woods colorimetric parameters when compared to other treatment methods.

Determinants of the Brazilian Amazon deforestation

The Amazon rainforest is the world’s largest biome, containing almost 50% of the planet’s known biodiversity and is the biggest source of fresh water, which is approximately one-fifth of the global reserves. However, the sustainable use of this ecosystem is threatened by several factors, and deforestation is the main problem. This study addresses the deforestation of the Brazilian Amazon forest, in particular evaluate the determinants of the deforestation process, using for this purpose, time-series of several socioeconomic factors from 1990 to 2015. The methodology applied included statistical analyzes based on the application of multivariate discriminant analysis with the stepwise criteria. The results showed that in order of importance cattle, roads network, population, logging and crop areas were the determinant variables of the deforestation in the amazon. Key words: Cattle, population, deforestation, Brazilian Amazon.

Tratamento Termomecânico e seus Efeitos nas Propriedades da Simarouba amara (Aubl.)

A pressao concentrada em pequeno grupo de especies tropicais torna necessario maior investimento em estudos e tecnicas de melhoramento em especies menos conhecidas na tentativa de direciona-las para usos multiplos. Este trabalho tem por objetivo avaliar a influencia do tratamento termomecânico nas propriedades colorimetricas e no modulo de elasticidade da madeira de marupa, com a finalidade de utiliza-la no segmento de pisos. Os resultados mostraram uma mudanca significativa, com efeito da temperatura na cor e na propriedade de elasticidade da madeira. Em geral, houve uma melhora no modulo de elasticidade dinâmico, enquanto a velocidade variou de acordo com cada tratamento apresentado, tendo-se valores mais baixos para os tratamentos com maior pressao. A madeira escureceu (menores valores L* e maiores valores de a*) com a aplicacao da temperatura. As cores da madeira de marupa apos os tratamentos, aliadas a propriedade de elasticidade potencializam essa especie como opcao para a industria de pisos.

Effect of drying process on marupá wood color

This research was developed after consultations with tropical timber exporters, who were facing problems with the colors of the species under study. This work aimed at characterizing Simarouba amara tropical wood color and verifying possible differences between the colorimetric parameters determined for the tangential and the radial directions of the wood, kiln-dried and air-dried. S. amara wood presents a grayish-white color. This color is mainly characterized by the b* coordinate (yellow pigment). Depending on the drying method used, the wood may present different colors for both tangential and radial directions. In both drying methods conducted, the wood presented lighter color in the tangential direction. Kiln-drying appeared to reduce S. amara wood lightness.

Propriedades da madeira de Pinus caribaea e Eucalyptus grandis estimadas por colorimetria

A utilizacao de tecnologias alternativas nao destrutivas tem se mostrado bastante eficiente na caracterizacao e na avaliacao da qualidade da madeira. Neste estudo, objetivou-se caracterizar tecnologicamente as madeiras de Pinus caribaea e Eucalyptus grandis por meio da Colorimetria. O estudo foi desenvolvido na Universidade de Brasilia (UnB), no Laboratorio de Engenharia e Fisica do Laboratorio de Produtos Florestais/LPF - Servico Florestal Brasileiro (SFB). As especies foram submetidas a ensaios convencionais de densidade basica, retratibilidade e flexao estatica. Para a determinacao dos parâmetros colorimetricos, utilizou-se um espectrofotometro, conforme metodologia adotada por Camargos (1999). A face radial da madeira e a mais adequada a coleta dos parâmetros colorimetricos e predicao das propriedades. A propriedade melhor estimada por essa tecnica foi a densidade, seguida pelo modulo de elasticidade (MOE) e modulo de ruptura (MOR).

Monitoramento da biodeterioração da madeira de três espécies amazônicas pela técnica da colorimetria

This work aimed to evaluate the use of colorimetry in the characterization of biodeterioration marupa, jequitiba and cumaru wood, submitted to white and brown rot. For this purpose, specimens of each Amazonian species were submitted to accelerated decay tests, according to American Society for Testing and Materials - ASTM D2017, during 20 weeks. With a colorimeter, the colorimetric parameters L* (lightness), a* (green-red coordinate), b* (blue-yellow coordinate) and total color change (ΔE) were determined weekly until the fourth week, and then every two weeks until the twentieth week. Additionally, it was determined the mass loss. The results indicated that the colorimetry was effective in monitoring of biodeterioration of wood, as well as to differentiate white and brown rot. The best predictions of natural resistance to white and brown rot were obtained with the parameters b* and L*, respectively. We also emphasizes the use of ΔE to estimate the biodeterioration of wood, because of their significant correlations with weight loss.

Caracterização do ataque de fungos apodrecedores de madeiras através da colorimetria e da espectroscopia de infravermelho

Wood samples of marupa ( Simarouba amara ) and andiroba ( Carapa guianenis ) were submitted to Trametes versicolor (white rot) and Gloeophylum trabeum (brown rot) fungi attack. Colorimetry was used to determine the color of the wood before and after wood decaying fungi. To evaluate the changes in chemical compounds levels in the wood samples, the diffuse reflectance medium infrared spectroscopy was used. Both wood were non resistant against white rot fungus, while with brown rot attack andiroba was resistant and marupa was not. After Gloeophyllum trabeum attack both woods changed to a darken color, and after Trametes versicolor attack andiroba changed to a lighter color and marupa darkened slightly, The analysis showed a reduction in the peak intensity of cellulose, hemicellulose and lignin, for both species, after Trametes versicolor attack and a reduction in the peak intensity of cellulose after Gloeophyllum trabeum attack.