Determinação dos extrativos totais e teor de celulose da madeira de Ipê submetida ao processo de modificação térmica

The demand for products from wood has been expanding, because of this, there is a need for studies related to the quality and application of these materials. Thus, the present research aimed to evaluate the extractive and cellulose content of Ipê wood submitted to the thermal modification process. To carry out the study, four individuals of Handroanthus chrysotrichus (Mart. ex DC.) Mattos, 11 years old, were slaughtered. Subsequently, samples measuring 2.5 x 2.5 x 41 cm were prepared and placed in an oven with forced air circulation, at temperatures of 120, 150, 180 and 210 ºC, for a period of 4 h. Then, random portions of the specimens were sectioned and ground in a knife mill, and then, sieved in the 40/60 mesh fraction, to carry out the chemical tests of total extractives and cellulose content. The data were processed and submitted to the Tukey average test, using the R software. The results of the chemical properties studied indicated variations according to the temperatures, not showing a stabilization trend between the treatments applied. A relationship between the behavior of these properties and the other technological characteristics of the works available in the literature was observed. In general, further studies are recommended on the chemical properties of wood of this species associated with the application of high temperatures.A demanda de produtos oriundos da madeira vem se expandindo, por conta disso, há a necessidade de estudos relacionados à qualidade e aplicação desses materiais. Com isso, a presente pesquisa teve como objetivo avaliar o teor de extrativos e de celulose da madeira de Ipê submetida ao processo de modificação térmica. Para realização do estudo foram abatidos quatro indivíduos de Handroanthus chrysotrichus (Mart. ex DC.) Mattos, com 11 anos de idade. Posteriormente, confeccionaram-se amostras de 2,5 x 2,5 x 41 cm, as quais foram acondicionadas em estufa com circulação de ar forçada, nas temperaturas de 120, 150, 180 e 210 ºC, por um período de 4 h. Em seguida, porções aleatórias dos corpos de prova foram seccionadas e trituradas em moinho de facas, e então, peneiradas na fração de 40/60 mesh, para a realização dos ensaios químicos de teor de extrativos totais e teor de celulose. Os dados foram processados e submetidos ao teste de médias de Tukey, utilizando o software R. Os resultados das propriedades químicas estudadas indicaram variações de acordo com as temperaturas, não apresentando uma tendência de estabilização entre os tratamentos aplicados. Uma relação entre o comportamento dessas propriedades com as demais características tecnológicas dos trabalhos disponíveis na literatura foi observada. De modo geral, são recomendados mais estudos acerca das propriedades químicas da madeira dessa espécie associados a aplicação de altas temperaturas

Effect of age and plant spacing on the energy properties of black wattle

The aim of this study was to determine the effect on the energy properties of different biomass components of Acacia mearnsii De Wild distributed in different plant spacings: 2.0x1.0 m, 2.0x1.5 m, 3.0x1.0 m and 3.0x1.5 m, in the 1st, 3rd and 5th years after planting. The experiment was performed in a complete randomized block design in three replicates. The following traits were determined: biomass (BIO), gross calorific value (GCV), basic density (BD), energy productivity (EP), energy density (ED), fixed carbon content (FCC), volatile material content (VMC) and ash content (AC) of different biomass components: wood, bark, branch and leaf. The effect of age significantly influenced all variables, providing an increasing distribution of BIO, EP, BD and ED. The four plant spacings provided different yields of BIO, EP, GCV and BD and the increased spacing caused a tendency to reduce BIO and EP values in all evaluated periods. In the 5th year, even being influenced by the spacing, the BD did not present a systematic increase or decrease over the provided living space. The three components of the trees induced a significant effect on the BIO, GCV, EP, FCC, VMC and AC variables.The aim of this study was to determine the effect on the energy properties of different biomass components of Acacia mearnsii De Wild distributed in different plant spacings: 2.0x1.0 m, 2.0x1.5 m, 3.0x1.0 m and 3.0x1.5 m, in the 1st, 3rd and 5th years after planting. The experiment was performed in a complete randomized block design in three replicates. The following traits were determined: biomass (BIO), gross calorific value (GCV), basic density (BD), energy productivity (EP), energy density (ED), fixed carbon content (FCC), volatile material content (VMC) and ash content (AC) of different biomass components: wood, bark, branch and leaf. The effect of age significantly influenced all variables, providing an increasing distribution of BIO, EP, BD and ED. The four plant spacings provided different yields of BIO, EP, GCV and BD and the increased spacing caused a tendency to reduce BIO and EP values in all evaluated periods. In the 5th year, even being influenced by the spacing, the BD did not present a systematic increase or decrease over the provided living space. The three components of the trees induced a significant effect on the BIO, GCV, EP, FCC, VMC and AC variables

Anatomia do lenho de Condalia buxifolia Reissek (Rhamnaceae)

São descritos e ilustrados os caracteres microscópicos da madeira de Condalia buxifolia Reissek, arbusto nativo no Estado do Rio Grande do Sul. Foram encontrados poros de diâmetro muito reduzido, em arranjo dendrítico, parênquima paratraqueal escasso e raios heterogêneos. Ressalta-se a presença de fibras de paredes muito espessas que, somado a outras características do lenho, indicam a espécie como uma das madeiras mais pesadas do Rio Grande do Sul. 

INFLUENCE OF ANATOMY ON THE MECHANICAL RESISTANCE OF WOODS IN AN AGROFORESTRY SYSTEM

This study aimed to evaluate the influence of anatomy on the mechanical resistance of Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis × Eucalyptus urophylla, and Schizolobium parahyba (Vell.) Blake from an agroforestry system. For this purpose, twelve 9-year-old trees were felled. To evaluate the anatomical properties, the specimens were taken from the diameter region at breast height (DBH at 1.30 m from the ground). To determine the mechanical characteristics, central planks from the DBH of the tree logs were removed to produce test specimens with dimensions of 2.5 × 2.5 × 41.0 cm. The modulus of elasticity, modulus of rupture, tension of the proportional limit, and maximum force were then evaluated. Conversely, test specimens with dimensions of 5 × 5 × 15 cm for were used for the transversal and longitudinal Janka hardness and perpendicular compression tests. The higher the cell wall fraction, vessel frequency, and ray frequency values, the better the mechanical properties. Conversely, with the increase in the fiber diameter, lumen diameter, vessel diameter, height, and width of rays, the values of the mechanical properties of wood are lower

AGENTES CAUSADORES DE ACIDENTES DE TRABALHO NAS SERRARIAS DA REGIÃO SUL DO BRASIL

A ocorrência de acidentes em serrarias no Brasil ainda apresenta números expressivos mesmo com os avanços tecnológicos e as atualizações das normas regulamentadoras. O objetivo desse artigo foi avaliar os acidentes de trabalho nas serrarias da região Sul do Brasil, quantificando as ocorrências e identificando o principal agente causador. Esse estudo foi realizado a partir de dados extraídos do Observatório de Segurança do Trabalho do ano de 2017, analisando os acidentes ocorridos em serrarias com atividades de desdobro de toras. A pesquisa mostrou que os principais agentes causadores dos acidentes em serrarias foram “agente biológico” e “máquinas e equipamentos”. O Paraná se destacou como o estado com mais registros de acidentes no ano de 2017, bem como número de óbitos, seguido de Santa Catarina e Rio Grande do Sul. Diante dos resultados obtidos, mais discussões são necessárias acerca dessa temática, a fim de mitigar os riscos que os trabalhadores são submetidos diariamente

Particleboard experimental production with bamboo, pine and mate for one product of new applications

Particleboard can be produced from a mixture of different lignocellulosic materials, which can be chosen depending on the density required for the panel and its applications. The aim of this study was to evaluate the mechanical properties of particleboard with bamboo, pine and mate for a new product of high density for the special applications currently served by HDF. Particles of bamboo (Phyllostachys aurea) finely chopped sticks of mate (Ilex paraguariensis) and commercial particles of southern pine (Pinus taeda) wood were used. These particles used 100 % by weight in the panel or in mixtures of 50 % each (three mixtures) or in a triple mixture of one third each, were glued in a drum-type rotary mixer with melamine-urea-formaldehyde (MUF) resin, and pressed in hydraulic press at 120 °C and 5,88 MPa for 10 minutes, up to 6 mm thickness. The panels were produced with 0,90 g∙cm-3 nominal density and, after pressing, were conditioned at 20 ºC and 65 % relative humidity. Statistical was performed by means the variance analysis and simplex centroid experimental design, with three replicates. It was found the use of pine particles contributed mainly to increase the panel's strength and stiffness, while the use of mate particles facilitated internal bond strength. The results compared with the ANSI A208.1 indicate that the panels with potential for use as floors and other applications requiring medium to high mechanical strength. The mixtures modeling showed that the water absorption, the strength and stiffness in bending and the internal bond strength are explained by the cubic model, while the thickness swelling and hardness are explained by the quadratic model. The best physical and mechanical properties results were found for the pine, bamboo and mate same ratio mixture

SPECTROSCOPY AND ROCKWELL HARDNESS TO CHARACTERIZE THE DETERIORATION OF WOOD TREATED WITH NATURAL PRODUCT

The objective of study was to characterize wood deterioration in samples with conventional and natural treatments using Rockwell hardness and spectroscopy. Five acacia trees were used to make 70 samples, of which 20 were treated with tannin and 10 with a Copper Chrome Borate mixture (CCB), while 10 samples exposed to fungus received no treatment and 30 were used as unexposed controls. The specimens for preservative treatments were saturated with the solutions, using full cell pressure in autoclave. Shortly after the treatment, the samples were exposed to Pycnoporus sanguineus for 16 weeks, using the accelerated rot test. Then, deterioration was evaluated by spectroscopy and Rockwell hardness. CCB was the most suitable to preserve wood hardness, followed by treatments with 10 and 5% of tannin, and all treatments presented similar values indicating they produced similar effects. Medium infrared spectroscopy analysis indicated that the material treated with 5 and 10% tannin showed the greatest similarity to the spectra from control samples

QUALITY OF Hovenia dulcis Thunb. ROUND FENCE POSTS SUBMITTED TO PRESERVATIVE TREATMENT

 This study aimed to test the hypothesis regarding the quality of Hovenia dulcis fence posts, which states that it varies according to the treatment period when subjected to the sap displacement method.. The experiment began with 15 round fence posts distributed vertically in tank containing copper sulfate, sodium dichromate and boric acid (CCB) solution at 2.5% concentration. In order to verify the influence of time on the efficiency of the method, the posts stayed in the preservative solution for periods of 3, 6, 9, 12 and 15 days, which  were assessed. Penetration and retention in three positions were analyzed, which corresponded to the regions of base, middle and top parts. With regards to treated wood, samples of each piece were prepared for testing in field test. Then, weight loss and bending properties were assessed. According to the results of penetration and retention, wood treated on the period of 15 days is the only one that can be used directly with the soil. After assessment of the weight loss, the periods of 12 and 15 days of treatment increased the classification of wood from moderately to strong resistant. The bending test showed significant reduction in rigidity and strength of the material, even in the treated ones, which demonstrates that the forest environment in which samples were exposed promoted the process of wood decomposition

ANATOMY AND DRYING OF WOOD OF FOUR SPECIES FROM AN AGROFORESTRY SYSTEM

Drying is an important process in the generation of wood products, as it increases the quality of the final products; however, it is influenced by various anatomical characteristics. The aim of this study was to evaluate the influence of anatomy on the drying of wood of Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis W. Hill × Eucalyptus urophylla S.T. Blake (hybrid), and Schizolobium parahyba (Vell.) Blake trees from an agroforestry system. Three trees aged 9 years were sampled for each species. The trees were removed from the study region when their diameter at breast height (DBH) was 1.30 m from the ground. Blocks were made with dimensions of 5.0 × 5.0 × 15.0 cm for the evaluation of oven drying and 1.5 × 1.5 × 2.0 cm for anatomical features. S. parahyba has the highest value of fiber diameter (35.1 µm) and lumen diameter (27.6 µm), whereas P. dubium had the highest value of cell wall thickness (6.8 µm). The average equilibrium moisture content was 10.98% after 40 days of drying. The anatomy of the wood influenced the drying of the four species intensity, which was related to humidity during all periods. The anatomical parameters that most influenced drying were fiber diameter (Pearson correlation coefficient: 0.77), lumen diameter (0.76), and fiber cell wall thickness (0.73); the higher the values, the greater was the drying intensity

Flexão estática e massa específica aparente da madeira de Inga marginata em diferentes condições de umidade

O presente estudo teve como objetivo determinar a flexão estática e a massa específica aparente da madeira de Inga marginata em diferentes condições de umidade. Foram abatidos três indivíduos com, aproximadamente, seis anos de idade. Para a determinação das propriedades estudadas foram seguidas as recomendações da norma ASTM D143-94. Observou-se redução superior a 1,2 vezes do módulo de elasticidade, módulo de ruptura, tensão no limite proporcional e força máxima na flexão estática em função da saturação das fibras. De maneira geral, as amostras apresentaram valores de massa específica aparente menores e maior resistência mecânica conforme a dessorção até a umidade de equilíbrio de 12%, sendo a madeira, nessa condição, classificada como moderadamente pesada